Respiratory

Current Trendsin the Neonatal ICU

SE Courtney, MD MS CL SD NMP ML DATMQBIGTSPMTAMLOT

Schneider Children’s Hospital

North Shore Long Island Jewish Health System

CPAP and Related Stuff

Plus ça change, plus c’est la même chose.

Pediatrics 1973;52:131

CPAP fell out of favor in some centers after the development of infant ventilators.

Concerns about ventilator-induced lung injury and the continued high incidence of chronic lung disease, coupled with the high profile given to CPAP by Columbia (in NY, not South America) have led to a CPAP comeback.

You’ve Seen This Before

If insufficient CPAP is used, the lung is not “open” and is subject to mechanical stress and inflammatory response just like with mechanical ventilation.

CPAP on high FiO2 (indicating atelectasis) may be worse than intubation, surfactant administration and lung protective ventilation

Methods of Delivering CPAP Devices

•Underwater Bubble

–Short Nasal Prongs

–Long Nasal Prongs

•Conventional Ventilator

–Endotracheal Tube

–Nasal Prongs

•Variable Flow (Fluidic)

–Nasal Prongs

–Nasal Mask

Theoretical Benefits

•Underwater Bubble

–Inexpensive

–?Oscillation causes ventilation

•Conventional Ventilator

–Inexpensive

–Easy and available

•Variable Flow

–More stable CPAP Pressures

–Lowest Work of Breathing

Bubble, Bubble, Boil and Trouble

What do we know about Bubble NCPAP?

• Columbia in NYC likes it.

• It’s cheap.

Bubble data:

The world’s literature on bubble CPAP consists of

3 small studies

Bubble Trouble

• Lee et al, A comparison of underwater bubble CPAP with ventilator-derived CPAP in premature neonates ready for extubation. Biol Neonate, 1998

- 10 infants, crossover design

- CPAP given with ETT

-bubble group showed decrease in minute volume and reduction in respiratory rate

Bubble Trouble

Pillow and Travadi, Bubble CPAP: Is the noise important? Pediatric Research 2005

• Bench study; decreasing compliance of lung model increased magnitude and frequency content of pressure oscillations

• Bubbling may enhance lung volume recruitment

Bubble TroubleLiptsen et al, Bubble CPAP vs Infant Flow, J Perinatology 2005

• 18 infants, each infant was his own control, order of devices randomized

• Resistive WOB, resp rate, phase angle all greater with bubble compared to IF.

Current study underway: bubble vs conventional NCPAP.

Conclusions…

• Bubble NCPAP appears similar to other forms of continuous-flow NCPAP. It is unclear whether the “bubbling” does anything

• More labored and asynchronous breathing is seen with bubble NCPAP compared to variable-flow NCPAP

• But…. More data are needed

What is Variable-Flow NCPAP?

A child with a very disturbed family life.

The Variable Flow NCPAP Family CourtThe Variable Flow NCPAP Family Court

•EME marries Hamilton; child Aladdin

•EME divorces Hamilton; gives child to SM

•SensorMedics renames child Infant Flow

•Hamilton has own child named Aladdin II

•Everybody sues everybody over children

•Hamilton renames its child, per court, Arabella

•EME divorces SensorMedics, takes its child

•SensorMedics has own child, “SMINGANP”

Stay tuned for the sequel…………..

Who is this kid, anyway?• Pressure supplies a jet flow, direction in response to pressures generated by the patient.

• On inspiration, the jet flows towards the nasal cavity, assisting in inspiration

• On exhalation, pressure in the nasal cavity the jet flows down the expiratory branch.

• Switching of high pressure control flow from inhalation to exhalation (“fluidic flip”) allows the device to follow the baby’s breathing from inhalation to exhalation, decreasing the work of breathing.

Moa G, Nilsson K, Zetterstrom H, Jonsson L. Critical Care Medicine 1988;16:1238

Who is this kid, anyway?

Childs, Neonatal Intensive Care, 2000

Is All NCPAP Created Equal?Controlled clinical trials: Physiologic data

• Courtney, Habib et al: Lung recruitment and breathing pattern during variable vs continuous flow NCPAP in premature infants: An evaluation of three devices. Pediatrics 2001

• Pandit, Courtney, Habib et al: Work of breathing during constant and variable flow NCPAP in preterm neonates. Pediatrics 2001

• Courtney, Habib et al: Changes in lung volume and work of breathing: A comparison of two variable flow NCPAP devices in VLBW infants. Pediatric Pulmonology 2003

Bottom Line: WOB less, lung recruitment better with variable-flow.

Is All NCPAP Created Equal?

Controlled clinical trials: Clinical data

Stefanescu B, Murphy P, Hansell B, Fuloria M, Morgan, T, Aschner J: Pediatrics 2003;112:1031

162 infants <1000gm randomized at extubation

Extubation Failure

38.1 38.5

0

20

40

60

80

100

Conventional Infant Flow

Fa

ilu

re (

%)

Stefanescu et al, Pediatrics 2003;112:1031

Kaplan – Meier curve depicting the time course of extubation failure within the first 7 days (168 hours)

Stefanescu et al, Pediatrics 2003;112:1031

Bottom Line:No difference.

Why?

• ?? Documented improved recruitment and decreased WOB with variable-flow not clinically important ??

• ?? Single-center bias ??

• ?? Some other reason ??

Reasons for Extubation Failure

58%

16%

15%

3%

8%

Apnea / bradycardia

FiO2>0.5, CPAP>8 cm

PaCO2>65, pH<7.25

Surgery

Other

Stefanescu et al, Pediatrics 2003;112:1031

Cochrane Review, 2002Devices and pressure sources for

administration of NCPAP in preterm infants

Conclusions:

“Short binasal prong devices are more effective than single prongs in reducing the rate of re-intubation. Although the Infant Flow Driver appears more effective than the Medicorp prongs the most effective short binasal prong device remains to be determined. The improvement in respiratory parameters with short binasal prongs suggests they are more effective than nasopharyngeal CPAP in the treatment of early RDS. Further studies incorporating longer-term outcomes are required. Studies are also needed to determine the optimal pressure source for the delivery of NCPAP.”

Questions…

• Are there any advantages of bubble NCPAP when compared to conventional continuous-flow NCPAP?

• Over the long term, is any one form of NCPAP more advantageous than any other?

• Is non-invasive ventilation combined with NCPAP advantageous? Is it safe?

• Are “new and improved” ways to provide NCPAP such as SiPAP any “better”?

….VF Family Court: THE SEQUEL

The Godfather, Viasys, intervenes. EME and SM get back together (sob!!) and merge (oh my!)

And a little sister is born,

SiPAP!!

SiPAP

• Provides bi-level CPAP

• “Sighs” 2-3cmH2O above the set CPAP level, time of the sighs and rate of sighs can be varied.

• MAY stimulate respiratory center, recruit unstable alveoli, decrease work of breathing.

SiPAPOff-loading Respiratory Work

• A shift up in lung volume by 4-6 ml/kg followed by a decrease in lung volume by 4-6 ml/kg will off-load respiratory work

0 . 0 0 0

1 . 0 0 0

2 . 0 0 0

3 . 0 0 0

4 . 0 0 0

5 . 0 0 0

6 . 0 0 0

S e c o n d s

cm

H2

O

World Literature on SiPAP

Long JA, Courtney SE: Bilevel Continuous Positive Airway Pressure (SiPAP) in Extremely Low Birth Weight Infants: An Observational Study of a New Device. Pediatr Res 2005: 3410A

9 infants

5 extubated successfully to SiPAP

3 reintubated for severe apnea

1 developed a pneumothorax while on SiPAP*****

SiPAP: Hot off the press

Migliori et al, Pediatric Pulmonology Sept 2005: Nasal bilevel vs. continuous positive airway pressure in preterm infants

20 babies, mean study weight 1kg, received 2 cycles of CPAP alternated with 2 cycles of bilevel CPAP, each phase lasted one hour.

Oxygen saturation and tcO2 increased, and tcCO2 and respiratory rate decreased during the bilevel CPAP periods.

“In my experience……”

“….a phrase that usually introduces a statement of rank prejudice or bias. The information that follows it cannot be checked, nor has it been subjected to any analysis other than some vague tally in the speaker’s memory.”

-Dr. Michael Crichton

SiPAP Observations/Recommendations

More data are needed

Seems to work in some very little babies

For extubation, seems to work better if you start at a higher sigh rate and work down rather than a low sigh rate and work up

SiPAP is NOT nasal IMV. Use the term “sigh” not “breath”

Keep sigh time at one second.

Make sure you’re not overdistending on xray

We are starting a work of breathing study soon. Did I say that more data are needed?

Nasal IMV

Available literature predominantly done with synchronized IMV on the old Infant Star.

Cochrane reviews of these data suggest decreased apnea and need for reintubation; work of breathing appears to be decreased.

BUT – most NIMV today is not synchronized, because few people have the old Stars anymore.

AND – there is little data on non-synchronized NIMV.

Nasal IMV is popular despite limited data.

PS – SiPAP is NOT nasal IMV!!!!

Vapotherm

More popular than McDonald’s

Data, data, where are the data?

World’s Literature on Vapotherm: 4 abstracts at SPR 2005

Chang GY, Cox CC, Shaffer TH: Nasal cannula, CPAP, and Vapotherm: Effect of flow on temperature, humidity, pressure and resistance

Bench study

Temperature/humidity were very close with Vapotherm and IF NCPAP.

Pressure/resistance at cannula with Vapotherm VERY high.

Vapotherm World Lit (cont)Saslow et al: Work of breathing during Vapotherm vs NCPAP for the treatment of RDS

Conventional NCPAP at 4 cmH2O vs Vapotherm at 3-5 lpm. No differences

Ramanathan A et al: High flow nasal cannula use in preterm and term newborns admitted to NICU: A prospective, observational study

Vapotherm used in 64 infants, max 6 lpm, babies did well.

Nair G, Karma P: Comparison of the effects of vapotherm and NCPAP in respiratory distress in preterm infants.

28 infants, ?CPAP level, ?Vapo flows. No differences

Thoughts on Vapotherm

More data urgently needed

PROBABLY ok up to about 6 lpm, likely providing about 5cmH2O NCPAP at that level

Should not be used at higher flows until more data on WOB and NCPAP provided are available.

Great unknown of the universe:

Why do neonatologists continue to do stuff without data even though they know better?

Trends in Mechanical Ventilation

Conventional Ventilation

• Tidal volume, tidal volume, tidal volume

• Support the patient’s own breaths

HFOV

• Sicker patients – not the same thing as “rescue”!!

• Open-lung strategy

• Extubate from HFOV

Transcutaneous Monitoring -Back to the Future

The Fall from Grace of Tc Monitoring

• Cumbersome equipment

• Skin burns

• Onset of pulse oximetry

Why We Need to Resurrect Tc Monitoring – Especially for CO2

• No good way to continuously monitor CO2 in infants – new end-tidal machines may be another way

• New Tc monitors easy to use

• No need to heat the sensor for TcCO2, so no skin burns

• New technology can cause rapid, dangerous swings in PaCO2

Why We Need to Resurrect Tc Monitoring – Especially for CO2

• Strong evidence that overventilation is damaging to the lungs and other organs

• Concerning evidence that very low PaCO2 may cause brain damage in the preterm infant.

Why We Need to Resurrect Tc Monitoring – Especially for CO2

New data raises concerns about brain damage from HYPERCARBIA

“Permissive hypercarbia” has never defined, and has never been shown to be safe in the newborn.

Important Points to Remember

• Transcutaneous CO2 monitors measure the CO2

tension at the surface of the skin. This is not the same thing as the PCO2 in the arterial blood, but the TcCO2 and the PaCO2 correlate.

• This means that when the PaCO2 goes up, the TcCO2 goes up, and when the PaCO2 goes down, the TcCO2 goes down.

Important Points to Remember

• Thus, though the PaCO2 and the TcCO2 numbers may not be the same, the trend is seldom wrong.

• Edema, poor perfusion, and increased skin thickness will increase the TcCO2 but the trend with the PaCO2 will still be there.

Important NICU Applications

• Initiation of HFOV

• Post-surfactant use

• Critical infants with fluctuations in ABGs

• Diagnosis of pneumothorax

Recommendation for TcCO2 Use

• Apply on trunk; abdomen or lower back best

• Calibrate at 40 degrees C.

• Change site every 6 hours

• Set limits!

• Not much can go wrong with the monitor – learn to troubleshoot.

Tc Monitor Test

The Tc alarm goes off. You should:

A. Increase the alarm limits

B. Turn alarms off

C. Ignore

D. Remove machine from patient, it obviously isn’t working

E. Check the patient and get a gas if necessary

Fun New StuffYou May Be Hearing About

Use of iNO in Preterm Infants

Additional Surfactant toPrevent/Lessen BPD

Jet Ventilation to Lessen BPD Severity

When in doubt, let the kid make his own damn vent changes!!