Secretion Management in the Mechanically Ventilated · PDF fileSecretion Management in the...

Secretion Management in the Mechanically Ventilated Patient

Richard D Branson MSc RRT FAARC

IntroductionSecretion Retention in the Ventilated PatientSecretion Clearance TechniquesRoutine Secretion Management in the Ventilated Patient

MobilizationHumidification

Maintaining the Endotracheal Tube LumenSuctioning

Novel Methods for Secretion Removal From the Endotracheal TubeThe Mucus SlurperThe Mucus Shaver

Special Endotracheal TubesIntermittent Techniques to Enhance Secretion Removal

Techniques to Simulate a CoughExternal Application of Force to Loosen SecretionsManual Rib-Cage CompressionIntrapulmonary Percussive Ventilation

Summary

Secretion management in the mechanically ventilated patient includes routine methods for main-taining mucociliary function, as well as techniques for secretion removal. Humidification, mobili-zation of the patient, and airway suctioning are all routine procedures for managing secretions inthe ventilated patient. Early ambulation of the post-surgical patient and routine turning of theventilated patient are common secretion-management techniques that have little supporting evi-dence of efficacy. Humidification is a standard of care and a requisite for secretion management.Both active and passive humidification can be used. The humidifier selected and the level ofhumidification required depend on the patient’s condition and the expected duration of intubation.In patients with thick, copious secretions, heated humidification is superior to a heat and moistureexchanger. Airway suctioning is the most important secretion removal technique. Open-circuit andclosed-circuit suctioning have similar efficacy. Instilling saline prior to suctioning, to thin thesecretions or stimulate a cough, is not supported by the literature. Adequate humidification andas-needed suctioning are the foundation of secretion management in the mechanically ventilated

Richard D Branson RRT FAARC is affiliated with the Department ofSurgery, Division of Trauma/Critical Care, University of Cincinnati, Cin-cinnati, Ohio.

Mr Branson presented a version of this paper at the 39th RESPIRATORY CARE

Journal Conference, “Airway Clearance: Physiology, Pharmacology, Tech-niques, and Practice,” held April 21–23, 2007, in Cancun, Mexico.

The author reports no conflicts of interest related to the content of thispaper.

Correspondence: Richard D Branson RRT FAARC, Department of Sur-gery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati OH45267-0558. E mail: [email protected].

1328 RESPIRATORY CARE • OCTOBER 2007 VOL 52 NO 10

patient. Intermittent therapy for secretion removal includes techniques either to simulate a cough,to mechanically loosen secretions, or both. Patient positioning for secretion drainage is also widelyused. Percussion and postural drainage have been widely employed for mechanically ventilatedpatients but have not been shown to reduce ventilator-associated pneumonia or atelectasis. Manualhyperinflation and insufflation-exsufflation, which attempt to improve secretion removal by sim-ulating a cough, have been described in mechanically ventilated patients, but neither has beenstudied sufficiently to support routine use. Continuous lateral rotation with a specialized bedreduces atelectasis in some patients, but has not been shown to improve secretion removal. In-trapulmonary percussive ventilation combines percussion with hyperinflation and a simulatedcough, but the evidence for intrapulmonary percussive ventilation in mechanically ventilated pa-tients is insufficient to support routine use. Secretion management in the mechanically ventilatedpatient consists of appropriate humidification and as-needed airway suctioning. Intermittent tech-niques may play a role when secretion retention persists despite adequate humidification andsuctioning. The technique selected should remedy the suspected etiology of the secretion retention(eg, insufflation-exsufflation for impaired cough). Further research into secretion management inthe mechanically ventilated patient is needed. Key words: secretion management, heated humidifica-tion, heat and moisture exchanger, percussion, postural drainage, insufflation, exsufflation, airway suc-tioning, closed-circuit suctioning, saline instillation, manual hyperinflation, silver coated endotrachealtube, Mucus Shaver, Mucus Slurper, intrapulmonary percussive ventilation. [Respir Care 2007;52(10):1328–1342. © 2007 Daedalus Enterprises]

Introduction

Secretion management in the mechanically ventilatedpatient consists primarily of adequate humidification andairway suctioning. The role of mechanical aids to improvecough and mobilize secretions is poorly defined and lackssupporting evidence in the intensive care unit (ICU). Evencommonly performed procedures such as percussion andpostural drainage have little support from the literature.This paper will review the evidence for secretion-manage-ment techniques in the mechanically ventilated patient andintroduce some new techniques that are early in develop-ment.

Secretion Retention in the Ventilated Patient

Mechanically ventilated patients are at risk for retainedsecretions from a myriad of causes. Endotracheal intuba-tion disrupts the mucociliary escalator and predisposes thepatient to infection,1,2 which increases the volume andtenacity of mucus.3 Relative immobility of the mechani-cally ventilated patient confined to bed can lead to atelec-tasis, impaired cough, and retained secretions.4 Upper-ab-dominal and thoracic surgery frequently lead topostoperative atelectasis, weak cough, and secretion reten-tion.5 Muscle weakness associated with prolonged ICUstay may also contribute to secretion retention.6 Finally,fluid status, particularly fluid restriction in the mechani-cally ventilated patient, may contribute to thickened se-cretions. When any or all of these coexist, the problem iscompounded.

Secretion Clearance Techniques

Management of secretions in the mechanically venti-lated patient includes routine standard of care therapiessuch as humidification, suctioning, and mobilization. Whenthese routine methods fail, intermittent therapy is employed,with a variety of techniques, to simulate a cough, loosensecretions, drain secretions via positioning, or a combina-tion of the three. Common respiratory therapy techniquesfor mechanical loosening of secretions include manual per-cussion and high-frequency chest wall compression, withor without postural drainage. These techniques can be com-bined with hyperinflation, as is the case with intrapulmo-nary percussive ventilation. A simulated cough maneuver,with either manual hyperinflation or insufflation-exsuffla-tion, may aid in expelling secretions in the patient withsecretion retention and neuromuscular weakness. Thesewill be addressed separately.

Routine Secretion Managementin the Ventilated Patient

Mobilization

“Up and out of bed” is a common postoperative orderaimed at preventing atelectasis, stimulating cough, andimproving circulation.7 This common sense approach iswidely practiced and uniformly supported, but has littlescientific evidence.8 Recently, Browning and colleaguesfound that in the first 96 postoperative hours the durationand quality of “up time” was poor, averaging only 3 min

SECRETION MANAGEMENT IN THE MECHANICALLY VENTILATED PATIENT

RESPIRATORY CARE • OCTOBER 2007 VOL 52 NO 10 1329

on postoperative day 1. They also showed no difference inpulmonary complications based on the duration of up time.9

Interestingly, greater duration of up time was associatedwith shorter stay. It remains to be proven if this is a cause-and-effect phenomenon or a “true, true, and unrelated”phenomena. It may simply be that patients who are im-proving tolerate more up time than their sicker counter-parts. Another study suggested that early mobilization isequivalent to postoperative coughing and deep breathing,10

which raises the question of whether these treatments areequally effective or equally ineffective.11 Clearly, investi-gation of early postoperative ambulation is warranted.

Humidification

Heating and humidifying the inspired gas is an estab-lished standard of care during mechanical ventilation,12,13

but the minimum requirements and optimum devices andsettings for humidification are less clear. The ability of anydevice, regardless of operation, to prevent drying of se-cretions depends on delivered gas temperature and relativehumidity.14,15 Absolute humidity is the amount of watervapor present in a gas. Relative humidity is the ratio of theabsolute humidity to the maximum absolute humidity. Rel-ative humidity is perhaps most important, as any deficitmust be provided by the tracheobronchial tree.

Assessing the adequacy of humidification is difficult. Anumber of potential surrogates for comparing humidifica-tion techniques have been suggested, including secretionvolume and consistency, incidence of endotracheal tube(ETT) occlusion, changes in ETT effective diameter and/orresistance, suctioning frequency, and requirement for nor-mal saline instillation.14,16–18 Measurements of secretionvolume are inherently flawed. Secretion volume maychange with the number of suctioning attempts, patientposition, use of aerosolized medications, and saline instil-lation. Excessive humidification may cause an increase insecretion volume, and insufficient humidification may re-sult in a decrease in secretion volume because mucus be-comes encrusted in the airways.16 In my experience, se-cretion volume measurements are poorly reproducible andoften reflect the individual practice of the clinician ratherthan the condition of the patient, so secretion volume is notreliable for comparing secretion-management techniques.

Heated Humidification Versus Heat and Moisture Ex-changer for Humidification and Secretion Management.A comparison of the ability of heated humidifiers versusheat and moisture exchangers (HMEs) to optimize secre-tion management requires measurable and reproduciblevariables. Those most frequently described are ETT oc-clusion and changes in effective inner diameter of the ETTresulting from encrusted secretions. Narrowing of the ETT

and ETT occlusion have been described with both heatedhumidifiers19–21 and HMEs.22–25

During use of a heated humidifier and heated-wire cir-cuit, ETT occlusion is associated with an increase in gastemperature from the humidifier chamber to the patient.As gas temperature rises, relative humidity falls. Gas en-tering the ETT at a humidity deficit absorbs moisture fromsecretions in the ETT and large airways.19 This problemcan be avoided by maintaining a constant temperature fromthe chamber to the airway, and by using a connecting tubebetween the heated-wire circuit and the airway, whichallows for cooling and a relative humidity of 100%. Theproblem of caregivers creating a large temperature differ-ence between the chamber and the airway to reduce con-densate in the heated-wire circuit, which increased the riskof ETT occlusion, undoubtedly led to introduction of heatedhumidifiers with no such clinician-set control.26

Occlusion of the ETT during HME use occurs second-ary to poor HME performance, changes in ambient con-ditions, leaks, and patient conditions (eg, body tempera-ture, minute ventilation, and fluid status).22–25,27,28 HMEperformance plays a large role, and hygroscopic HMEsclearly outperform hydrophobic HMEs.29–31 Even the mostefficient HME allows a net loss of heat and moisture fromthe respiratory tract, so prolonged use is associated with agreater incidence of ETT occlusion. There is also evidencethat HMEs are less effective in patients with chronic lungdisease, although this is not well understood.32

Hess evaluated studies of HMEs and heated humidifierswith and without a heated-wire circuit, using a meta-anal-ysis to determine the risk of ETT occlusion33 Figure 1depicts the results of that analysis. The studies in thatmeta-analysis represent a cumulative total of over 1,000patients and the analysis indicates that the risk of ETTocclusion is nearly 4 times greater with HME than withheated humidification. That finding argues against the use

Fig. 1. Meta-analysis of risk of endotracheal tube occlusion with aheat and moisture exchanger (HME) versus with a heated humid-ifier (HH). RR � relative risk. (Adapted from Reference 33.)



of HMEs in patients with retained secretions, and for lim-iting HME use to � 5 days.

Another issue with HME use in patients with increasedsecretions is the possibility of occlusion of the HME. Thishas not been specifically studied, but frequent soiling ofthe HME has been reported as a trigger for switching toheated humidification.34 In our experience, HMEs are mostfrequently occluded by blood or pulmonary edema fluid.However, in the presence of copious sputum production anHME can become completely or nearly completely oc-cluded (Fig. 2).

A series of studies have compared the effects of humid-ification devices on in vivo and in vitro ETT resistance,inner diameter, and surface area.35–38 In an early study,Villafane et al measured the effective inner diameter bymeasuring flow and pressure at the proximal ETT andthreading a hollow catheter to the distal tip of the ETT.This allowed measurement of the pressure drop across thetube. They made these measurements in patients on a dailybasis. Three groups of patients were studied: group 1 useda heated humidifier, group 2 used a hygroscopic HME,and group 3 used a hydrophobic HME. ETT resistanceincreased with duration of use in all 3 study groups, but thehydrophobic HME group had the highest resistance. Fig-ure 3 shows these changes in 4 patients in that study.

Several authors have used acoustic reflectometry to eval-uate changes in ETT inner diameter.36–38 Boque et al mea-sured loss of effective inner diameter and found that within48 hours � 60% of ETTs lost � 10%. All patients used anHME.36

Shah and Kollef found similar losses of intraluminal sur-face area when they compared unused to used ETTs.37 Themost convincing evidence comes from Jaber et al, who usedacoustic reflectometry to compare ETT volume and resis-tance over 10 days. Half the patients used heated humidifiersand half used HMEs. At day 5 there was no difference in thechanges in ETT resistance. However, at day 10 the HMEgroup had a 19 � 18% increase in resistance, compared to an8 � 12% increase in the heated humidification group (Fig. 4).The authors concluded that ETT resistance increases withduration of use and that HMEs increase ETT resistance morethan do heated humidifiers.38

These findings are clinically important because severalauthors have described ETT resistance as a cause of wean-ing failure.39–41 The findings also reinforce the conceptthat the selection of a humidification device should bebased on the expected duration of use and the presence ofthickened secretions.34 In the mechanically ventilated pa-tient with secretion-management issues (thick and/or co-pious sputum), heated humidification is preferred. Whenmechanical ventilation is expected to last more than 96hours, a heated humidifier should be used from the outset.

Maintaining the Endotracheal Tube Lumen

Humidification maintains mucociliary function and as-sures that secretions remain hydrated so they can be ex-

Fig. 2. Heat and moisture exchanger nearly completely occludedby mucoid secretions.

Fig. 3. Example of repeated pressure and flow measurements ob-tained from representative mechanically ventilated patients whoreceived humidification via heated humidifier (HH) or one of 2 brandsof heat and moisture exchanger (HME) (Dar Hygrobac 35254111,and Pall BB2215). (Data from Reference 35.)

Fig. 4. Percent change in resistance of the endotracheal tube (ETT)at the middle and end of a 10-day course of mechanical ventilation(MV) with either a heated humidifier (HH) or a heat and moistureexchanger (HME). (Data from Reference 38.)



pectorated. In the mechanically ventilated patient, the ETTcuff abruptly stops the mucociliary escalator. At this pointthe second most important secretion-management tech-nique, suctioning, becomes required. The suctioning pro-cedure may include pre-oxygenation and/or hyperinflation,depending on the technique. Suctioning methods includeopen-circuit suction, closed-circuit suction, and minimallyinvasive (or shallow) suctioning. One contentious issue insuctioning is instillation of normal saline either to loosensecretions or to stimulate a cough as an aid to secretionmobilization. Studies are also now being done on when tosuction. These issues are reviewed below.

Suctioning

Removal of tracheobronchial and upper-airway secre-tions to maintain airway patency and reduce the risk ofsilent aspiration is a standard of care.42,43 Suction cathetersdiffer greatly in design but have the same general charac-teristics. Most adult catheters are 48–56 cm in length, toallow the catheter to reach the mainstem bronchi. Thedistal tip of the catheter has several openings for secretionremoval, and the proximal portion contains a thumb portthat the practitioner occludes to activate the suction. Thedistal tip is blunt, to avoid trauma to the mucosa or per-foration of the tracheobronchial tree. The side holes in thedistal tip of the catheter also serve to minimize the risk oflocal tissue damage. If the catheter had only one openingat the distal end, the mucosa could be drawn into thecatheter tip and torn during withdrawal of the catheter.Suction catheters should be transparent to allow visualinspection of secretions, rigid enough to pass through theETT, yet pliable enough to traverse the airways withoutdamaging the mucosa.

Few comparative evaluations of suction catheter designshave been accomplished.44,45 Shah et al compared six14 French suction catheters in a bench study that evaluatedthe characteristics (side-hole placement) that facilitated theremoval of simulated mucus.45 The viscosity of the sim-ulated mucus was altered to represent thin and thick se-cretions. Shah et al found that the major factors that affectsecretion removal are the position and size of the catheterside holes. Offset side holes were associated with bettermucus clearance. The catheters they tested are depicted inFigure 5. These findings are important for future catheterdesigns.

Open Versus Closed Suctioning. Two decades ago thestandard of care for suctioning was a single-use, dispos-able, open-circuit suction catheter. The patient was dis-connected from the ventilator, hyperventilated, and hyper-oxygenated with a self-inflating manual resuscitator. Thepatient was then disconnected from the manual resuscita-tor and the suction catheter was passed into the ETT toremove secretions. The manual resuscitator was also usedto simulate a cough, by stacking breaths or giving largevolumes. This procedure was also known to result in bothhemodynamic instability and hypoxemia.

In the last decade, closed-circuit suction catheters havebecome popular for a number of reasons, including pre-vention of problems associated with disconnecting the pa-tient from the ventilator, reduced cost, and reduced expo-sure of caregivers to infectious materials. Comparisons ofclosed-circuit and open-circuit suctioning techniques sug-gest that there is no difference in their ability to evacuatesecretions.46,47 Because the patient does not need to bedisconnected from the ventilator during closed-circuit suc-tioning, the positive end-expiratory pressure (PEEP) is

Fig. 5. Comparison of catheters studied by Shah et al, showing the positions of the side holes and other design characteristics. (FromReference 45, with permission.)



maintained and hypoxemia and ventilator malfunction maybe reduced. There is also evidence that the closed-circuitsystem reduces caregiver and environmental contamina-tion, although the evidence regarding this is weak. Studiesof prolonged use of closed-circuit suction catheters sug-gests that, compared to open-circuit suctioning, the inci-dence of ventilator-associated pneumonia is either loweror unchanged.48–64 Interestingly, many clinicians have sug-gested that, by preventing disconnection of the circuit fromthe ETT, closed-circuit suctioning reduces the risk of ven-tilator-associated pneumonia. Although this is an attractivehypothesis, it has not been studied. When closed-circuitsuctioning was introduced, it was my (RDB) opinion thatclosed-circuit suctioning removed less secretions thanopen-circuit suctioning, and that eliminating the manualresuscitator not only prevented the clinician from “feel-ing” the compliance, but removed the ability to create acough to propel mucus cephalad. I (RDB) was often toldthat the sound of closed-circuit suctioning is different be-cause the airway is closed. The satisfying sound of secre-tions being removed with open-circuit suctioning was alsolost. However, if PEEP is preserved during closed-circuitsuctioning, it means that while we are trying to suctionsecretions out, the ventilator is blowing them back into thepatient. So closed-circuit suctioning, despite its advantages,may be an inferior secretion-removal device.

This hypothesis was recently tested by Lasocki and col-leagues, who compared the effects of open and closedsuctioning in patients with respiratory failure.65 They foundthat closed suctioning prevented suction-related hypox-emia, but that secretion removal was reduced. They sug-gested that during open suctioning the disconnection fromthe ventilator and loss of PEEP simulates a cough andpropels mucus upward. They also postulated that the dis-connection from the ventilator during open-circuit suction-ing increases the pressure differential, which enhances suc-tioning, whereas during closed-circuit suctioning theventilator gas delivery that maintains the PEEP forces se-cretions away from the suction catheter. In that study,secretion volume was reduced with closed-circuit suction-ing unless the suction pressure was increased to�400 mm Hg, which restored secretion removal volume(Fig. 6). However, this greater negative pressure was notassociated with hypoxemia. They suggested the use of apost-suctioning recruitment maneuver to restore alveolarrecruitment.65 Despite these findings, closed-circuit suc-tioning appears to have more advantages than disadvan-tages. In patients with retained secretions, increasing thevacuum pressure may be required to improve secretionremoval, but gas exchange and ventilator performanceshould be monitored closely.

Bronchial Suctioning. During routine endotracheal suc-tioning, the suction catheter most likely enters the right

main bronchus if the catheter is advanced far enough,because the angle from the trachea into the left main bron-chus is more acute than that into the right main bronchus.As such, the left lung is less likely to be suctioned. At-tempts at suctioning the left mainstem have been describedand have ranged from simple maneuvers to the use ofspecial catheters.66–68 One simple way of suctioning theleft main bronchus is by turning the head to the right toincrease the likelihood of the catheter entering the leftmainstem. The same effect may be gained by placing thepatient in the left lateral position and attempting to usegravity to guide the catheter to the left lung.

Specialized catheters that have a curved tip enter the leftmain bronchus in up to 90% of cases. The success ofbronchial suctioning can be affected by tube position, pa-tient body and head position, and type of tube (ETT vstracheostomy tube). We have not found selective endo-bronchial suctioning to be a necessary routine technique.Frequent changes in patient body position facilitate move-ment of secretions to the carina, where they can be suc-tioned. In patients with infectious processes confined tothe left lung, selective endobronchial suctioning may proveuseful.

Deep Versus Shallow Suctioning. Prior to suctioning aneonate, the length of the suction catheter is often mea-sured to prevent traversing the tip of the ETT and thus toprevent trauma to the neonatal tracheobronchial mucosa.Shallow (or minimally invasive) suctioning means passingthe suction catheter tip to the end of the ETT, but nofarther. Suctioning past the ETT tip is therefore calleddeep suctioning. In adults this issue is less frequently dis-cussed. A recent meta-analysis of this topic found that thesupporting literature is poor and that no definitive conclu-sions could be made.69 Ahn and Hwang examined secre-tions from neonates following deep and shallow suction-ing and found evidence of detached ciliated airway cellswith deep suctioning, but no more secretions were re-moved than with shallow suctioning.70 They suggested

Fig. 6. Tracheal aspirate mass at 2 different vacuum pressureswith closed-circuit suctioning in patients with acute respiratorydistress syndrome. (Data from Reference 65.)



that deep suctioning has no advantage, causes unnecessarytrauma, and should be avoided.

In adults, van de Leur et al found that minimally inva-sive suctioning resulted in fewer recollections of suction-ing by ventilated patients. However, this was not associ-ated with less discomfort with the suctioning procedure.71

In a large study of adult patients, they also found thatminimally invasive suctioning resulted in fewer hemody-namic and gas-exchange adverse effects but had no effecton duration of ventilation and other outcomes.72 In thelatter study the traditional suction catheter was 49 cm long,compared to 29 cm for the minimally invasive catheter.

This issue essentially pits deep suctioning (to removethe most secretions) against shallow suctioning (just keep-ing the ETT clear of secretions). The limited evidenceseems to suggest that minimally invasive suctioning is aseffective at secretion removal, but has fewer adverse ef-fects, so the “first, do no harm” principle suggests thatminimally invasive suctioning should be preferred, butfurther study is necessary.

Saline Instillation. During the suctioning procedure it iscommon for some practitioners to instill 5–10 mL of nor-mal saline in an attempt to thin the tracheobronchial se-cretions. This practice remains a point of contention, andstudies have failed to show any advantage from salineinstillation. Our studies of humidification techniques re-vealed that the only correlation between saline instillationand patient care is practitioner preference.34 That is, ourresearch failed to show that saline instillation is used uni-formly or has any benefit in terms of liquefying secretions.Saline instillation frequently does cause the patient to coughviolently, which may aid in the secretion-removal process.From a conceptual standpoint, instilling saline to stimulatea cough makes sense, but the current literature does notsupport the routine use of saline instillation. From a mucusrheology perspective, the properties of mucus are unlikelyto change with the addition of water unless some physicalmeans of mixing the two is accomplished. As well, severecoughing episodes and bronchospasm occasionally mayresult from saline instillation.

There is also some concern that the use of saline maydislodge bacteria-laden biofilm from the ETT and into thesmall airways. A host of recent studies found that salineinstillation failed to produce any of the intended effects,while potentially causing more pulmonary infections.73–89

Based on this evidence, saline instillation to thin secretionsis, at best, unsupported and, at worst, dangerous.

When to Suction. Routine suctioning should be avoided.Instead, patient assessment, including auscultation and vi-sual inspection, should be used to determine the need forsuctioning. In recent years, ventilator graphics have beenused to detect the need for endotracheal suctioning. Jubran

and Tobin,90 Guglielminotti et al,91 and Zamanian andMarini92 all described alterations in the pressure and flowcurves that might suggest the need for suctioning. Figure 7depicts changes in the expiratory flow signal that suggestairway secretions. The most common finding is a sawtoothpattern in the expiratory flow signal, caused by secretionsin the large airways. This finding is also seen with con-densate in the expiratory limb of the ventilator circuit, sovisual inspection of the circuit should be included in theevaluation.

Visaria and Westenskow demonstrated the ability to de-tect ETT occlusion using an automated evaluation of pres-sure and flow signals.93 They were able to distinguishairway obstruction from bronchospasm and changes in chestwall compliance. Similar systems might be developed todetermine when suctioning is required.

Endotracheal suctioning is associated with many com-plications, and should be undertaken only when necessary,keeping the potential complications in mind. Minimizingthese complications by minimally invasive suctioning andsuctioning only when necessary, based on reliable detec-tion methods, may both be routine in the future.

Novel Methods for Secretion RemovalFrom the Endotracheal Tube

The Mucus Slurper

Intermittent closed-circuit suctioning is the current stan-dard of care in mechanically ventilated patients. Kolobowand colleagues recently described a system (the “MucusSlurper”) that provides automated, intermittent suctioningof the ETT lumen (Fig. 8).95 The Mucus Slurper is a

Fig. 7. Characteristic sawtooth pattern of the expiratory flow sig-nal, which suggests the need for suctioning.



modified continuous subglottic suctioning ETT. The endof the ETT is modified by cutting off the portion beyondthe cuff, and attaching a plastic ring with eight 1.3-mmholes. The suction lumen is extended to apply suction tothese 8 holes.

In Figure 8, the pressure and flow waveforms show theeffects of activating suction to the 8 holes at the end ofinspiration. The system draws 135 mL over 0.3 seconds. Inthis preliminary evaluation in an animal model, the systemdid not affect ventilator performance. There was someconcern about auto-triggering, but most ventilators have a“lockout” period following completion of the inspiratorytime, which is near the 0.3-second time frame. Figure 9shows the system for control of suction pressure and tim-ing.

This very preliminary evidence indicates that in an an-imal model without pulmonary disease, the ETT lumenremains clean. Presumably, as the secretions approach theETT, they are removed through the 8 narrow lumens. Re-cently, the Mucus Slurper system was tested for 72 hoursin an animal model that compared every-2-min activationwith the mucus slurper to every-6-hour suctioning.95 There

were no differences in airway colonization between thegroups. However, inspection of the ETT showed less se-cretion accumulation in the Mucus Slurper group. Kolobowand colleagues measured protein content in the expiratorycondensate as a marker of secretion movement up theETT. The protein concentrations were lower in the MucusSlurper group. How this system will perform in a patientwith copious, tenacious secretions remains to be seen.

The Mucus Shaver

Kolobow and colleagues also described the MucusShaver system for removing secretions from the inner wallof the ETT.96 The Mucus Shaver is a manually operatedsystem that scrapes the inside of the ETT to remove se-cretions (Fig. 10). The Mucus Shaver is placed inside theETT, much like a stylet. The balloon is inflated and theshaving heads are forced against the inner wall; the deviceis then withdrawn over 3–5 seconds to remove secretions.The intention is to return the ETT resistance characteris-tics to their pre-use values. In an animal model with nor-mal lungs, the Mucus Shaver maintained a clean internal

Fig. 8. The Mucus Slurper endotracheal tube, a modification of a CASS (continuous aspiration of subglottic secretions) endotracheal tube.The CASS suction line runs to the hollow, concentric, vinyl suction ring in the tip of the tube (magnified at lower right). Mucus is intermittentlysuctioned via the eight 1.3-mm holes in the perimeter of the tube’s tip. The graph at lower left shows the expiratory airway pressure (Paw)and flow waveforms during one suctioning event by the Mucus Slurper (dashed line) and without aspiration (solid line). The Mucus Slurperactivates within a few milliseconds of the start of exhalation (A), and aspirates 135 mL from the expiratory flow, with no decrease in thepositive end-expiratory pressure. The aspiration lasts 0.3 s (B). (From Reference 94, with permission.)



lumen and reduced biofilm accumulation. The clinical rolefor this device remains uncertain.

Special Endotracheal Tubes

ETTs are designed for a number of special situations.There are wire-reinforced ETTs, ETTs for laser surgery,specially shaped ETTs to improve the operative field, andETTs for high-frequency ventilation. Silver-coated and sil-ver-impregnated ETTs are designed to reduce bacterialcolonization and maintain a patent lumen.

Silver has long been appreciated for its bacteriostaticproperties.97–99 Older clinicians will remember the timewhen all tracheostomy tubes were silver or silver-platedstainless steel. Silver-coated and silver-impregnated uri-nary catheters and central venous catheters have been usedfor over a decade.100 Silver has other medically useful

properties, including prevention of biofilm formation, re-duction in bacterial burden, and reduction in inflamma-tion. To test the potential bacterial burden reduction in therespiratory tract with silver-coated ETTs, Olson et al per-formed an experimental study in 11 ventilated dogs. Thesilver-coated ETTs reduced biofilm formation and therewas a significant lumen-narrowing difference between theETTs. Five of the 6 noncoated ETTs (83%) and none ofthe 5 coated tubes had a narrowing of � 50%. The coatedtubes not only reduced the bacterial burden, with a statis-tically minor risk of colonization, but also delayed theformation of luminal side colonization from 1.8 � 0.4 d to3.2 � 0.8 d.101

A recent prospective randomized phase II pilot studytested silver-coated ETTs in ICU patients. The main ob-jective was to determine whether a silver-coated ETT re-duced the incidence and/or delayed the onset of coloniza-

Fig. 9. Aspirated mucus is collected in a 25-mL mucus trap connected to the external suction line of the Mucus Slurper. A water trapprevents accumulation of water in the solenoid valve. The controller is connected via a pressure transducer to the respiratory circuit, andsynchronizes the opening of the solenoid valve during the early expiratory phase. When the valve opens, the circuit is connected to avacuum source (suction level is adjustable with a vacuum controller). The frequency of activation and the duration of suction are adjustablevia an electronic controller. An alarm activates when no synchronized aspiration is detected. (From Reference 94. with permission.)



tion, compared to a noncoated ETT, in mechanicallyventilated patients. There was a significant reduction inmicrobiologic burden with the silver-coated ETT.102 Thehigh bacterial concentration on the inner surface of a stan-dard ETT can play a role in the development of late-onsetventilator-associated pneumonia when biofilm fragmenta-tion occurs. This fragmentation can be facilitated by air-way suctioning or installation of saline. The future role ofsilver-coated or silver-impregnated ETTs remains to bedetermined.

Intermittent Techniquesto Enhance Secretion Removal

The term respiratory therapy often refers to “treatments”provided by the respiratory therapist to aid in lung expan-sion, prevent atelectasis, and mobilize retained secretions.Within the realm of respiratory therapy for secretion mo-

bilization are techniques that simulate a cough, that loosenmucus through external forces (chest clapping, vibration),and positioning. In many cases these methods combinetwo or three of these techniques. Each will be considered.

Techniques to Simulate a Cough

Manual Hyperinflation. Manual hyperinflation duringsuctioning was at one time a common procedure. By stack-ing small breaths or providing a large breath and holdingit, the respiratory therapist could simulate and/or stimulatea cough. This is separate from the technique of manualhyperinflation aimed at lung recruitment.

Manual hyperinflation with a self-inflating bag for se-cretion removal is a popular practice in the United King-dom and some former United Kingdom colonies inAsia.103–110 Recent studies indicate that the mechanicalventilator can also be used to achieve hyperinflation,with similar results.111,112

As a separate technique, manual hyperinflation is notcommonly used for secretion removal in the mechanicallyventilated patient in the United States. Manual hyperinfla-tion delivers a large-tidal-volume breath over a prolongedinspiratory time, followed by an inspiratory hold and rapidrelease of pressure. The goal is to simulate a cough andpropel mucus cephalad. Most studies have suggested thatas peak expiratory flow is increased, secretion removal isenhanced. The evidence for the efficacy of manual hyper-inflation is scant. Several studies have shown improvedcompliance and oxygenation after manual hyperinflation,but the findings about changes in secretion volume havebeen inconsistent.111–114

Manual hyperinflation is not without risk. High airwaypressure and large lung volumes produce adverse hemo-dynamic effects and can injure the lung via barotraumaand/or volutrauma.115,116

Insufflation-Exsufflation. Mechanical insufflation-ex-sufflation (in-exsufflation) is done with the CoughAssistIn-Exsufflator (Respironics, Murrysville, Pennsylvania),which is a stand-alone device that insufflates a fairly largevolume of gas into the lungs, and then rapidly reverses toa negative pressure that exsufflates the gas from the lungs,which simulates a cough and propels secretions cephal-ad.117,118 The active expiratory portion of the CoughAssistIn-Exsufflator’s operation separates it from manual hyper-inflation.

To date, the CoughAssist In-Exsufflator has primarilybeen used in patients with neuromuscular weakness whoare on noninvasive ventilation.119–121 There are no clinicaltrials of the CoughAssist In-Exsufflator in mechanicallyventilated patients in the ICU. In our experience, we haveused the CoughAssist In-Exsufflator in the neurosurgicalICU, in patients with head and spinal cord injuries and

Fig. 10. A: Mucus Shaver. B: Mucus Shaver inflated. C: MucusShaver inflated inside an endotracheal tube. Shaded areas � sil-icone rubber. (From Reference 96, with permission.)



who retained secretions. These have primarily been tra-cheostomized patients who cannot cough because of mus-cle weakness or altered mental status. The intermittent useof the CoughAssist In-Exsufflator appears to assist in se-cretion removal. Studies of in-exsufflation in these pa-tients are warranted.

External Application of Force to Loosen Secretions

These techniques include percussion and postural drain-age, high-frequency chest wall vibration, rib-cage com-pression, and chest physiotherapy. Each of these therapiesuses patient positioning and postural drainage to facilitatesecretion removal, so these will be considered together.

Percussion and Postural Drainage. Though percussionand postural drainage are widely used in patients withcystic fibrosis in the out-patient setting, use of percussionand postural drainage in mechanically ventilated patientsis sporadic. Conceptually, the mechanisms are similar. Inthe mechanically ventilated patient with retained secre-tions, chest clapping is supposed to mechanically loosensecretions. It is interesting to note that percussion andpostural drainage are often used to treat or prevent atelec-tasis in the absence of secretion retention. There is noknown mechanism by which percussion and postural drain-age can improve atelectasis, unless it is by removal ofmucus plugs.

The literature on percussion and postural drainage inmechanically ventilated patients is poor. In fact, more pa-pers have described complications from percussion andpostural drainage (pain, anxiety, atelectasis, elevated ox-ygen consumption) than have found any positive ef-fects.122–128 At present, in mechanically ventilated pa-tients the use of percussion and postural drainage, orchest physiotherapy, or other external vibration meth-ods is unfounded.

High-Frequency Chest Wall Compression. This topicwas covered by Chatburn in his contribution to this con-ference.129 Suffice it to say that at present there is noevidence for the use of chest wall compression in themechanically ventilated patient. One case report describedremoval of bronchial casts with high-frequency chest wallcompression130 but it has not been systematically tested inmechanically ventilated patients.

Manual Rib-Cage Compression

Manual rib-cage compression (also known as “squeez-ing”) refers to manually applying external force to the ribcage to increase expiratory flow and thus facilitate secre-tion removal. The literature is confined to a couple ofreports from Japan, which found no increase in secretion

removal with squeezing.131,132 As with various other tech-niques, anecdotal reports of success predominate.

Kinetic Therapy. The literature is replete with descrip-tions of the use of rotating beds designed to prevent ven-tilator-associated pneumonia and treat atelectasis.133–139

However, study of these beds’ effect on secretion clear-ance has been limited.140 Davis et al compared secretionclearance, lung mechanics, and gas exchange in paralyzedpatients with acute respiratory distress syndrome random-ized to receive manual turning, manual turning with per-cussion and postural drainage, continuous lateral rotation,or continuous lateral rotation with percussion and posturaldrainage performed by the pneumatic cushions of the bed.Each of 20 patients received each treatment, in a random-ized order, for 6 hours. The combination of continuouslateral rotation and percussion and postural drainage pro-duced more secretions in this small group of paralyzedpatients, but no other benefits were identified. As withmost of the intermittent techniques discussed here, contin-uous lateral rotation seems to make common sense forsecretion management, but there is no evidence to supportits efficacy.

Intrapulmonary Percussive Ventilation

Chatburn’s contribution to this conference129 also dis-cussed intrapulmonary percussive ventilation, which com-bines the secretion-loosening effects of mechanical per-cussion with hyperinflation to facilitate cough and propelmucus cephalad. Study of intrapulmonary percussive ven-tilation in mechanically ventilated patients has been lim-ited to a few case reports.141–143

Summary

Management of secretions in the mechanically venti-lated patient requires adequate humidification and appro-priate suctioning. The level of humidification required hasbeen not well defined, but it is clear that in a patient withthick and copious secretions a heated humidifier is pre-ferred to an HME. A heated humidifier should also be usedfor prolonged ventilation (� 5 d). Suctioning should bedone when clinical signs (auscultation, visible secretionsin the tube, graphic displays) suggest secretions in thelarge airways. Closed-circuit suctioning has some advan-tages over open-circuit suctioning with regard to prevent-ing de-recruitment, but neither technique is superior forremoving secretions. Some interesting new suctioningmethods have been described, and future studies shoulddetermine if these have merit.

The use of intermittent secretion-removal techniques,including percussion and postural drainage, manual hyper-inflation, insufflation-exsufflation, and intrapulmonary per-



cussive ventilation, have a dearth of supporting evidenceand should be used cautiously. Routine use of these tech-niques is not supported by the literature.

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Discussion

MacIntyre: That was terrific, asalways. I have a bunch of questions,let me just start. There’s been dis-cussion about the ventilator as a mu-cus clearance tool, specifically theuse of high-frequency ventilation,and Kolobow has been very keen ontracheal-gas-insufflation-type tech-niques.1 What’s your take on usingHFO [high-frequency oscillation] ortracheal gas insufflation as a mucusclearance?

1. Trawoger R, Kolobow T, Cereda M, Gia-comini M, Usuki J, Horiba K, Ferrans VJ.Clearance of mucus from endotrachealtubes during intratracheal pulmonary ven-

tilation. Anesthesiology 1997;86(6):1367–1374.

Branson: Well, I think they’re sep-arate. If you remember, when Miro-slav Klain first came out using high-frequency jet ventilation,1 one of theclaims was you could ventilate the pa-tient with the ETT cuff not inflatedand it would prevent aspiration; andalong with that there was the idea thatif there was mucus in the airway youwould propel it forward. I think eitherof those techniques, high-frequency orTGI [tracheal gas insufflation] to re-move secretions, are really dependenton how well you humidify that gas.Because if you blow a high flow of

gas in tracheal gas insufflation intothe ETT with the thought of propel-ling mucus forward, like with the re-verse thrust catheter that Kolobow de-veloped, and it’s not adequatelyhumidified, you will make secretionproblems worse.

I don’t know that high-frequencyoscillation is any different than IPV[intrapulmonary percussive ventila-tion] or anything else that we do interms of secretion clearance via “shak-ing”—the question is, does that shak-ing actually eliminate or loosen secre-tions? I have to tell you, when you dopercussion postural drainage with theHill-Rom bed, it can create a lot ofpressure, and we actually had a pa-



tient in a study2 who had a pulmonaryartery catheter who could not toleratethe percussion, because whenever hegot the percussion the catheter wouldwhip against his heart and would causehim to go into runs of ventricular fi-brillation. So it does actually createquite a bit of percussion into the air-way. I don’t know if that answers yourfirst question or not.

1. Klain M, Keszler H, Stool S. Transtrachealhigh frequency jet ventilation prevents as-piration. Crit Care Med 1983;11(3):170–172.

2. Davis K, Johannigman JA, Campbell RS,Marraccini A, Luchette FA, Frame SB,Branson RD. The acute effects of body po-sition strategies and respiratory therapy inparalyzed patients with acute lung injury.Crit Care 2001;5(2):81–87.

MacIntyre: I have just been in-trigued with Ted Kolobow’s ideas overthe years, and he’s come up with a lotof them. He has these ETTs with gillson them that don’t really seal; and, asyou say, he argues that you can ven-tilate people without cuffs, which hebelieves facilitates movement of themucus out of the airway. It is an in-teresting area of research, but proba-bly not ready for prime time yet.

1. Trawoger R, Kolobow T, Cereda M, Spar-acino ME. Tracheal mucus velocity remainsnormal in healthy sheep intubated with anew endotracheal tube with a novel laryn-geal seal. Anesthesiology 1997;86(5):1140–1144.

Chatburn: Rich, can you say any-thing about the relationship betweenthe loss of effective ETT diameter andany kind of observable clinical effecton patients’ work of breathing?

Branson: There are a couple of pa-pers1,2 that look at the changes in thework of breathing associated withthese changes in ETT diameter. Wehad our lesson in physics yesterday,so anything that decreases the diame-ter is going to increase the work onthe patient. There are a couple of pa-pers, most of them from Orlando Kir-ton3–5 that suggest that there are pa-

tients who fail spontaneous breathingtrials because their ETTs have becomenarrowed by retained secretions, andthat there is an iatrogenic reason forweaning failure.

1. Shah C, Kollef MH. Endotracheal tube in-traluminal volume loss among mechani-cally ventilated patients. Crit Care Med2004;32(1):120–125.

2. Jaber S, Pigeot J, Fodil R, Maggiore S,Harf A, Isabey D, et al. Long-term effectsof different humidification systems on en-dotracheal tube patency: evaluation by theacoustic reflection method. Anesthesiology2004;100(4):782–788.

3. Rumbak MJ, Walsh FW, Anderson WM,Rolfe MW, Solomon DA. Significant tra-cheal obstruction causing failure to weanin patients requiring prolonged mechanicalventilation: a forgotten complication oflong-term mechanical ventilation. Chest1999;115(4):1092–1095.

4. Kirton OC, Banner MJ, Axelrad A, DrugasG. Detection of unsuspected imposed workof breathing: case reports. Crit Care Med1993;21(5):790–795.

5. Kirton OC, DeHaven CB, Morgan JP,Windsor J, Civetta JM. Elevated imposedwork of breathing masquerading as venti-lator weaning intolerance. Chest 1995;108(4):1021–1025.

Rubin: Rich, that was a brilliantsummary. I would like to continue ona rant that you started, vilifying theaddition of saline, not only in terms ofthe extra time. What interests me, andwhat I think should require severe cor-poral punishment is: if saline really iseffective in loosening up secretions sothey can be suctioned, I can’t under-stand why so many people put downthe saline and then bag the secretionsand the saline way down deep in thelungs, well beyond the reach of anysuction catheter. I’ve never been ableto understand why people would fol-low saline instillation with bagging. Isthis done at other people’s institutions?

Branson: All the time. I think thenormal way that is done is that some-body puts saline down, the patientstarts to cough, they bag them realgood, and then try to give them a bigbreath so that they kind of simulate acough and then suction it out. I’ve ac-tually talked to Dean [Hess] about this

before. I know that we don’t want tolose PEEP in recruitment in the me-chanically ventilated patient, but Ithink when we went to closed-circuitsuctioning, we lost the old way wherewe bagged the patients and did a sim-ulated cough that, I thought, seemedto help clear secretions. I realize thereare other reasons, ventilator-inducedlung injury, not to give big volumes,but I always thought that—in somepatients even now I will take them offthe ventilator and try to give them asimulated cough. But I agree with you;we probably ought to change the pol-icy to be, put the saline in and as soonas the patient starts to cough, suction,and then if you want to do some othertechnique for hyperventilation or man-ual inflation, you should do it.

Schechter: Studies of neonates andchildren on mechanical ventilationfailed to provide support for the rou-tine use of airway-clearance therapiesfor the prevention of atelectasis.1,2

However, there is some suggestion thatit helps to promote resolution of atel-ectasis when it develops in these chil-dren.3 Is there any adult literature onthat?

1. Flenady VJ, Gray PH. Chest physiotherapyfor preventing morbidity in babies beingextubated from mechanical ventilation. Co-chrane Database Syst Rev 2002(2):CD000283.

2. Argent AC, Morrow BM. What does chestphysiotherapy do to sick infants and chil-dren? Intensive Care Med 2004;30(6):1014–1016.

3. Deakins K, Chatburn RL. A comparison ofintrapulmonary percussive ventilation andconventional chest physiotherapy for thetreatment of atelectasis in the pediatric pa-tient. Respir Care 2002;47(10):1162–1167.

Branson: There are some review ar-ticles—one is in Critical Care Medi-cine1—that are written by physiother-apists that say that chest PT [physicaltherapy] is by far the most effectivetreatment for a lobar atelectasis. But Ican find absolutely no evidence thatthat is true. It has never made anysense to me that somehow you canpercuss the lung that has collapsed and



make it open. And I don’t know, andnot to put Dave [Pierson] on the spot,but Dave actually has a case reportthat’s about 20-something years oldnow, where they did chest PT to re-move a foreign body.2 So there arethings like that. I will ask the pulmo-nologists—I thought I would for sureget into the literature and find that atherapeutic bronchoscopy was a reallygood evidence-based technique for re-moving secretions; and it’s not!There’s not a single study that sug-gests that a clean-out procedure withbronchoscopy helps, and we do thisall the time! Go in to do a bronchos-copy for a bronchoalveolar lavage forculture, and while we’re in there wesee that the lung is a mess, and sowhoever the ICU person is spends thenext 20 minutes cleaning and suction-ing mucus; and we all feel better aboutthat when we’re done. But there is noevidence that I can find that that doesanything.

1. Krause MF, Hoehn T. Chest physiotherapyin mechanically ventilated children: a re-view. Crit Care Med 2000;28(5):1648–1651.

2. Raghu G, Pierson DJ. Successful removalof an aspirated tooth by chest physiother-apy. Respir Care 1986;31(11):1099–1101.

Pierson:* At Harborview we did astudy in the late 1970s, when JohnMarini was a fellow,1 in which weprospectively randomized patientswith acute lobar atelectasis detectedon a chest x-ray to receive vigorouschest PT, which included posturaldrainage, bronchodilator inhalation,and clapping—with and without im-mediate bronchoscopy to try to suckout the “mucus plug” and relieve theatelectasis. First of all we found thatto do the study we had to take a chestx-ray after randomization and imme-diately before we did anything, be-cause so often the atelectasis just went

away on its on, which obviously wouldhave skewed the results. But in thatrelatively small and probably under-powered study, we were unable to de-tect any difference in the rate of res-olution of the atelectasis whenbronchoscopy was added to chest PT.

We embarked on a subsequent studyin which we tried to do chest PT withand without the clapping, in exactlythat same setting, and unfortunatelythat wound up getting abandonedabout two thirds of the way throughfor poor recruitment of patients. Andthat’s, I think, where the literaturestands on this. You are certainly cor-rect that bronchoscopy is very oftenperformed in patients who have per-ceived secretions, perceived atelecta-sis, radiographic abnormalities thatmight be atelectasis, or fever or hyp-oxia that could be due to atelectasis,but that is not an evidence-based prac-tice.

1. Marini JJ, Pierson DJ, Hudson LD. Acutelobar atelectasis: a prospective comparisonof fiberoptic bronchoscopy and respiratorytherapy. Am Rev Respir Dis 1979;119(6):971–978.

Rogers: What is the mechanism ofaction whereby silver inhibits bacte-rial biofilm in bacterial formation inthe tubes?

Branson: I don’t know if I can an-swer that fully. There are some goodstudies in the engineering and bioma-terials literature1–3 that silver preventsbacterial growth and adhesion to sur-faces—to this day we use silver-coatedFoley catheters for patients who haveneed to be chronically catheterized.We used silver-coated central venouscatheters because the silver preventsinfection—it’s not bactericidal, it’sbacteriostatic. Again, from the histor-ical standpoint the interesting thingwas that in the early part of our coun-try’s history, prostate problems wereas common as they probably are to-day. Supposedly Ben Franklin had asilver straight catheter that he used onhimself to empty his bladder and pre-

vent infection. So the idea that silveris somehow bacteriostatic has beenaround for 200 or more years.

1. Balazs DJ, Triandafillu K, Wood P, Chevo-lot Y, van Delden C, Harms H, et al. Inhi-bition of bacterial adhesion on PVC endo-tracheal tubes by RF-oxygen glowdischarge, sodium hydroxide and silver ni-trate treatments. Biomaterials 2004;25(11):2139–2151.

2. Donelli G, Francolini I. Efficacy of antiad-hesive, antibiotic and antiseptic coatings inpreventing catheter-related infections.J Chemother 2001;13(6):595–606.

3. Jansen B, Kohnen W. Prevention of bio-film formation by polymer modification.J Ind Microbiol 1995;15(4):391–396.

Rogers: When you say bacteriosta-tic, what does that mean comparedwith bactericidal?

Branson: A bactericidal activelykills bacteria, whereas a bacteriostaticprevents further growth. Like I said,there are some interesting studies inthe literature about silver-coated tubesand preventing the adhesion to the sur-face of the ETT. Bruce, I don’t knowif you can understand that or explainthat better from an engineering per-spective?

Rubin: No, that was all absolutelycorrect. That is exactly it. Ionized sil-ver apparently prevents the growth ofbacteria in biofilms. It’s not very goodat killing them, but it doesn’t allownew growth and development in plank-tonic forms floating off and doing morebad stuff. But that’s exactly what itdoes. Just as you described.

Branson: All of you have beenaround as long or longer than I have,and when Dave was talking about thatpaper in the 1970s, I said, “Well Imissed that, because I was in the 8thgrade.” But when I first started in re-spiratory therapy, all the heated hu-midifiers for ventilators had copperwool in them. So it looked like a Brillopad, only it was all copper, and theidea was that the copper would pre-vent the growth of any bacteria insidethe humidifier. So these ideas that met-

* David J Pierson MD FAARC, Division ofPulmonary and Critical Care Medicine, Har-borview Medical Center, University of Wash-ington, Seattle, Washington.



als somehow can be, I guess, helpful,aren’t new. There are studies going onnow looking at this very issue: doesthe silver-coated tube prevent this ad-herence of secretions to the ETT?

Myers: Maybe not as often as thesaline debate comes up, but about ev-ery 3 times the saline debate comesup, comes up the debate about patientswho have thick, tenacious secretionsusing a diluted sodium bicarbonatedown there to break up those secre-tions. Is there anything in the litera-ture that supports that, or not?

Branson: No, there’s not. There aretreatments described where they ad-minister Mucomyst down a broncho-scope channel directly onto secretions,with the idea of breaking up the mu-cus. But I have to tell you, if you haveever seen Mucomyst applied directlyto the bronchial mucosa, when doneit’s all irritated and red and inflamedand looks terrible. There’s a group thatused to do what’s called BBS, “bicar-bonate, bag, and suction,” where theyput sodium bicarbonate down the ETT.It’s the same idea with hypertonic sa-line solution to try and somehowchange the secretion volume, butthere’s no evidence that I know of thatany of that works.

Fink: Just a comment Rich. I ap-preciate the mechanical concept thatwas shown by the Rouby study usingthe open or closed suction catheter,1

but as our discussions went yesterday,the quantity of secretions isn’t nearlyas important in this case as whether ornot the use of the different catheteraffected the frequency for the require-ment to suction. Obviously, if you havesecretions in the airway, you want toclear them, but if you clear them andyou have no greater time componentdifference or frequency difference,does size really matter?

1. Lasocki S, Lu Q, Sartorius A, Fouillat D,Remerand F, Rouby JJ. Open and closed-circuit endotracheal suctioning in acute lunginjury: efficiency and effects on gas ex-

change. Anesthesiology 2006;104(1):39–47.

Branson: I will be careful. I thinkwhat the study shows is that if youhave secretions that have moved them-selves to within reach of the suctioncatheter, you’d like to remove them.Whether or not that makes some long-term difference, I don’t have any idea,and I don’t know that we could evereven study that.

Fink: The other question I had wasthe depth of suctioning. There’s a dif-ference between being at the predictedend of the ETT, and the method ofextending the catheter till it stops,withdrawing about a centimeter, andthen applying suction. Have thosetechniques been differentiated?

Branson: No comparisons. Thereare 3 or 4 studies in the literature; theDutch study looked at adult patients,and compared the secretion volumethat was eliminated.1 And then theywent in and did outcomes, too. Howlong did the patient stay on the ven-tilator? How many days of care? Howmuch time in the ICU? All that otherstuff—incidence of ventilator-associ-ated pneumonia—no difference be-tween just placing the suction catheterto the end of the ETT or further downthan that; and potentially, obviouslythere is probably less damage, and Iguess you could make the argumentthat poking the carina with the suctioncatheter probably is not a good thingand might actually damage the carinaand lead to greater infection.

1. van de Leur JP, Zwaveling JH, Loef BG,van der Schans CP. Endotracheal suction-ing versus minimally invasive airway suc-tioning in intubated patients: a prospectiverandomised controlled trial. Intensive CareMed 2003;29(3):426–432.

Wojtczak:* Very nice presentation,Rich. I’m a pediatric pulmonologist,and one of the treatments that I’ve

started using, in conjunction with mypediatric surgery colleagues, is pro-phylactically placing selected chil-dren, postoperatively on HFCWC[high-frequency chest-wall compres-sion]. Specifically, children who haveundergone posterior spinal fusion. Ina medicine-based-evidence way, I planto take a closer look to see how thesechildren fare in the immediate post-operative period.

There is an abstract; it’s a smallstudy done by the group at OaklandChildren’s Hospital, that looked at us-ing the HFCWC via the Vest, postop-eratively in adolescents after posteriorspinal fusion.1 The authors reportedthat HFCWC with the Vest is a clin-ically safe and effective airway-clear-ance technique in ventilated or post-extubat ion pat ients who haveundergone spinal fusion, and sug-gested that further studies should beperformed. The other question I hadwas, Do you know of any studies thathave looked at the use of HFCWC fornonventilated children with tracheos-tomy tubes?

1. Gomez A, Acker R, Buehler C, NewmanV. Successful use of high frequency chestwall oscillation in pediatric post operativespinal fusion (abstract). Respir Care 2002;47(9):1035.

Branson: Not that I’m aware of. It’salmost always done in acutely ill pa-tients with ETTs, but I would assumethe same thing.

Wojtczak: So often we will have achild come in, acutely ill with a tra-cheostomy in and spend 10–14 dayson a ventilator in the pediatric ICU.But that’s not been studied as far asyou know?

Branson: No, it has not.

Wojtczak: Thank you.

McMahon:* It seems that, due tothe depressed respiratory system and

* Henry Wojtczak MD, Naval Medical Center,San Diego, California, representing Monaghan/Trudell Medical.

* Carolyn McMahon, Cardinal Health, River-side, California.



all of the complications that occur withmechanical ventilation, that adult pa-tients coming off the ventilator, eitherout of surgery or post-extubationwould be great candidates for airway-clearance techniques, devices, proba-bly a combination of positive airwaypressure, aerosol, and oscillation. Arethere any studies ongoing or promptedbased off of this discussion to look atairway-clearance devices for earlierextubation, keeping the patient stable,just to support the patient post-sur-gery to be able to get them out of theICU earlier, to extubate earlier—sim-ilar to getting them up out of the bed,studies based on how they fare over-all?

Branson: I think the answer is no.In critical care what we do is look topeople who fail extubation, and welook for ways to prevent them frombeing re-intubated. And that’s beingstudied, noninvasive ventilation, maskCPAP [continuous positive airwaypressure] to prevent those things fromhappening. But, clearly, once the pa-tient gets extubated in the ICU, therespiratory care group mobilizes, es-sentially—to make a pun about thisentire conference—to the bedside, andour therapists routinely will includeaerosol therapy, PEP [positive expira-tory pressure], and, if need be, naso-tracheal suctioning in patients who arerecently extubated, who have a secre-tion problem. My patient popula-tion—I have all of these surgery andtrauma patients, and except for oncein a while, like when we get a 76-year-old with a hundred pack years ofsmoking, in a car accident—I don’tsee very many people who come inwith secretion problems. When youare perfectly normal until you get shot,stabbed, or hit by a car, you don’thave a lot of respiratory mechanicsissues, unless you develop pneumo-nia. I think it’s different in the surgi-cal ICU, in the medical ICU, and inthe neurological ICU, where patientswith spinal cord injury and head inju-ry—that, to me, is an area that just

really needs investigation with all ofthese devices.

Pierson: Following on that, I agreethat the circumstance you’ve identi-fied is clearly one in which we des-perately need more knowledge, andworking in a surgery trauma unit likeyou do, Rich, one of the populationsof patients who I think most needs tobe studied and most needs help is thenonintubated elderly patient with acouple of rib fractures or other inju-ries who has either not been intubateddeliberately from the beginning to tryto avoid all of that, or has just beenextubated but now has to contend withthe effects of heavy sedation, recenttrauma, impaired clearance mecha-nisms because of their rib fractures,their pain, or other things, with or with-out a history of previous lung diseaseor smoking.

Branson: This is a different issue,but in my experience the elderlytrauma patients—“elderly” gets olderall the time, right?—but to me, some-body who’s more than 70, who’s beenin an automobile accident and requiresmechanical ventilation, I would preferthat we trach [tracheostomize] all ofthose people, because I think it helpsthem get off the ventilator faster. Ithink it helps them get out of the ICUfaster; that’s just my clinical impres-sion. It’s really hard to go to familiesand say, “Hey, we’re doing a studywhere there is a 50–50 chance we’regoing to trach Dad, and, no, we don’tknow that he needs it.” It’s just kindof hard to do, but I think there areretrospective reviews that suggestearly tracheostomy in the elderly pa-tient actually improves outcomes.1

And secretion clearance becomes in-finitely easier when you have a chan-nel to suction through.

1. Arabi Y, Haddad S, Shirawi N, AlShimemeri A. Early tracheostomy in inten-sive care trauma patients improves resourceutilization: a cohort study and literature re-view. Crit Care 2004;8(5):347–352.

Hess: Rich, you talked about clear-ing secretions from below the ETT,but what about clearing them fromabove the ETT?

Branson: I didn’t address the ideathat you have to suction above the ETTbecause you have this collection oforopharyngeal secretions, which webelieve are the reservoir for creatingventilator-associated pneumonia.Some of us have experience with theCASS [continuous aspiration of sub-glottic secretions] ETTs, the continu-ous subglottic suction where you havea little hole in the ETT just above thecuff, and it continuously suctions outthe material there. Early studies1 sug-gested that in patients who were re-cently intubated without infection, thatreduces the incidence of early pneu-monia, and the early pneumonias areprobably due to aspiration. But itdoesn’t reduce the incidence of latepneumonia, which are usually noso-comial infections—Pseudomonas,MRSA [methicillin-resistant Staphy-lococcus aureus], Acinetobacter, orwhatever, whichever one you have.And that’s because those are probablyspread through another mechanism,poor hand-washing by us, contamina-tion of the environment, and thingslike that.

1. Safdar N, Crnich CJ, Maki DG. The patho-genesis of ventilator-associated pneumonia:its relevance to developing effective strat-egies for prevention. Respir Care 2005;50(6):725–739.

Restrepo: I have a couple of com-ments. I don’t know if you’ve noticedthis, but once you read the Cochranereview published in 2004 on normalsaline instillation and the use of deependotracheal suction technique,1 it justends with a comment, that even thoughthere is no study that could actuallyjust be analyzed, or just summarized,they consider it to be unethical to usethe deep suction technique in light ofanecdotal data. Three years ago weconducted a survey, which of coursecarries the usual limitations of valid-



ity associated with questionnaires, atChildren’s Healthcare of Atlanta at Eg-leston. We did survey 102 clinicians,27 RTs [respiratory therapists] in thisgroup. Back then, suctioning and sa-line instillation were considered to bethe most common procedures per-formed in any ICU—and I believe theystill are. It might have changed a littlenow that we performed SBTs [spon-taneous breathing trials] on a daily ba-sis and we keep RTs busier than whatit was 3 years ago.

All we found—in the process of justwriting the manuscript—was that thereis a lot of variability on what thenurse’s perception is in terms of theindications from normal saline instil-lation on endotracheal suction, and thefrequency. What we could not believewas that, even among RTs, there wereseveral unknowns in terms of theamount of negative pressure that needsto be applied, the amount of normalsaline recommended according to agegroups, and for how long these suc-tion events should last. Some clini-cians were confused about differencesbetween deep and shallow suctioning.

Also, as a comment, it is amazing

that when you review literature, sev-eral publications that have evaluatedthe effects of normal saline instilla-tion go back to the 1970s. It has been30 years of documenting the adverseeffects of both normal saline instilla-tion and endotracheal suctioning, andwe still haven’t been that proactive interms of just trying to create guide-lines that are followed by everyone;as Richard said, there’s a lot of vari-ability. Some clinicians are going tobe using normal saline no matter what.What is funny about this survey is thatwhen you compare this response tothe ones we got 5 years before, thecurrent trend to respond, “No, we don’tuse normal saline,” is quite differentwith the routine use a few years back.Of course, as you turn around, someclinicians will do the complete oppo-site to what their answer was: deepsuction and normal saline instillation.Just a comment.

1. Spence K, Gillies D, Waterworth L. Deepversus shallow suction of endotrachealtubes in ventilated neonates and young in-fants. Cochrane Database Syst Rev 2003;(3):CD003309.

Branson: The people around the

room who do ICU and ventilator pa-tients, how many of your therapistsnormally put saline down the ETT?Are you guys sure about that? I thinkyou made some good points. Like Isaid; there are a couple of therapistswho work at my place who have beenthere 25, 30 years, and they are go-ing to put saline down every singletime, and there’s nothing you are go-ing to do to change that practice. It’sgoing to take more than explainingthat when you put saline down thetube in a patient with a head injuryand it increases their intracranialpressure when they cough. These iso-lated incidents showing that there isa difference. I think most people justhave the impression that it mighthelp, and it probably doesn’t hurt,and that’s why they continue to doit.

Restrepo: One final comment. Sofar—I’ve been very interested in thisfor years—the only real indication ofa routine normal saline instillation waswhen we conducted studies on partialliquid ventilation.

Branson: Totally different idea.



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