Procedural sedation analgesia

Ian Muir

Aims

❖ Introduction to PSA

❖ PSA in the high acuity setting

❖ Patient and staff safety - credentialing and supervisionverification of competency

❖ Patient selection

❖ Methods and selection of drugs

❖ Aftercare

Procedural sedation analgesia

❖ Intergral part of training - fundamental skill

❖ During performance of painful diagnostic and therapeutic procedures (esp. children)

❖ Improves patient care and satisfaction - anxiolysis and analgesia - facilitates timely intervention

❖ Significant risk for Cardiorespiratory, CNS depression

❖ Guidelines and advent of short acting drugs, improved non-invasive monitoring making this safe,common and practical

Challenges❖ Non elective!

❖ Limited or no prior history

❖ Time pressures

❖ Priorities – work balance

❖ Alternatives – is regional or local techniques appropriate

❖ Staffing - required personnel and their roles

❖ Patient selection and individualisation paramount

Levels of sedation❖ Minimal sedation – anxiolysis,normal CVS/Resp fx

❖ Moderate -still awake “conscious sedation” - Midazolam/Fentanyl - LP, I&D

❖ Deep sedation - purposeful response with repeated (painful) stimulation - where we want to be!

❖ General anaesthesia - unresponsive to pain/loss ofability to protect airway -Apnoea/hypoventilation

❖ Dissociative : Trance-like cataleptic state, amnesia analgesiaProtected airway reflexes

Preparation❖ Procedural sedation checklist

❖ Positioning - OSA/Obstruction airway risks -Adjunctive airways

❖ Assessment - ASA - ?too high for ED -ASA I-II preferred(mild systemic disease/healthy) - Difficult airway - Mallampati (OSA) -Risk benefit ratio analysis

❖ Monitoring - ETCO2 waveform capnography - > time to react/?no difference in outcome - Pulse oxymetry only changes very late

❖ Equipment and drugs check

Evaluation

❖ Presedation evaluation- Directed Hx/PE - Risk Ax -Discuss risks,benefits, limitation Parent/Gaurdian - document -Severity/Type underlying Dx -Pre procedural ASA level -Current medications/Allergies egg lecithin, soyabean oil

❖ Sedation during the procedure

❖ Post procedural recovery

Clinical evaluation❖ A- Obesity,Short neck,receding mandible,Large tongue

Trismus,Mallampati,Thyromental distance

❖ B- Auscultate - acute/chronic lung disease(URTI or COAD) - airway reactivity

❖ C- Rhythm disturbances, perfusion, reserve - induction related hypotension/vasodilatation

❖ GI- Fasting status (contentious) - No evidence in litera- that >fasting time reduces aspiration. 2-3h clear fluids 4-8 hours non-clear fluids and solids. Use of concomitant anti emetics unproven.Fasting may increase gastric pH and motility Dependent on aquity,urgency, depth of sedation required, co-morbid Data extrapolated from GA –emetogenic inhilational anaesthetics

❖ Hepato-renal disease : Elderly and very young : delayed metab

Personnel/Monitoring❖ Protocolised sedation policy highly advised

❖ Division of roles : Airway and proceduralist

❖ Close continuous observation by individual capable or recognition of complications and management thereof

❖ Visualization of mouth,chestwall motion - detect respcompromise. Airway obstruction, emesis, secretions

❖ Proficiency at drug delivery and pharmacology, rever-sal agents and advanced airway management

❖ Emperic documentation and accurate assessment of the depth of sedation

Monitoring❖ Comprehensive non-invasive monitoring: Sats, HR, BP,RR, ECG

❖ Capnography is more sensitive than SpO2 to detect hypotension, apnoea (however no change in mortality)Reduction of episodes of desaturation <95% by 15%

❖ BIS - processed EEG signal quantifying depth of sedation (60-70) from the frontal lobe – still requires more data for routine usepoor reproducibility

❖ Careful documentation prior,during and after sedation when drugs given - q5mins for deep sedation

❖ Verbalization of rescue plan for apnoea, cardio-respiratory collapse

❖ Period of risk when painful stimuli decreased post adequate IV sedation or reduction of fracture( loss adrenergic drive)

Resuscitation equipment

❖ Resuscitation bay- full advanced airway equipment for intubation and ventilation and Mx of arrest

❖ Bilateral large bore IV access and 1L crystalloid with pump infusion capacity, Apnoeic oxygenation (>DAWD)

❖ O2 -mask ventilation with high flow may mask apnoea if hyperoxic in absence of waveform capnography, but increases reserve, if ETCO2 not available ? suppl O2In general give O2 to reduce hypoxic episodes

❖ Suction,NPA,Guedel,BMV, Reversal agents

❖ Defib

Dissociation-slightly longer procedures

❖ Ketamine -spontaneous breathing, excellent analgesia - haemodynamically stable (mostly!) -1-2mg/kg slow IV push - within 45sec -initial brief period of apnoea (20sec) -emergence phenomena - “happy place” -pretreatment not really required unless history of emergence (midazolam) -Beware sympathomimetic response - HTN -Beware in the insane patient -Exceptionally low rate of complications -Growing body evidence that ketamine is protective in head injury due to NMDA blockade and does not increase ICP

Dissociative analgesia❖ Dissociation : “disconnection” of thalamoneocortical from limbic

system : non- competitive antagonism at NMDA receptors. Prevention of cortical centres receiving any sensory stimuli

❖ Subdissociative : <1mg/kg – potent analgesia agonism mu,kappa,delta opioid rec.

❖ Relative contra-indication in seizure disorders or raised IOP

❖ Frequently used in “austere poorly monitored setting in 3rd world” with very good safety profile

❖ Avoid in schizophrenics –may exacebate this condition

❖ Poor choice in excessive oropharyngeal stimulation, anatomic abN upper airway

Brief painful procedure❖ Fentanyl and Propofol(Phenol derivative – highly

lypophylic rapidly crosses BBB – effect in 40sec duration 6mins)

❖ 1-1.5mcg/kg Fentanyl prior to procedure(1-2min prior)

❖ 0.5-1.5mg/kg Propofol - 10-20mg bolusses(60sec)

❖ Rapid recovery(approx 1min), adequate pre-oxygenation(NRM)

❖ Duration matches length of the stimuli

❖ Beware frail elderly patient- CVS effects/prolonged sedation, dose reduction appropriate

Paediatric sedation❖ Ketamine : IV preferred 1-1.5mg/kg

IM 4-5mg/kg – useful if difficult IV access -longer sedation time, + vomiting -sedation less easily titrated Higher doses in children – High Vd

❖ Consider Atropine 0.02mcg/kg – hypersalivation Evidence : confers no benefit, not routine consider in for oral procedures tongue lac.

❖ Poor choice for CT/MRI – potential motion artifact

❖ CI : child <3months – resp complications, animal studies show apoptosis/neurodegeneration in developing brains due to NMDA antagonism

Paediatric sedation

❖ IV access : Combine IN Fentanyl and Nitrous gas

❖ Nitrous oxide : immediate analgesia,sedation, anxiolysis scavenging system NB

❖ Multimodal pain management approach : - Pharmacological - Cognitive - Behavioural - Physical

❖ Family involvement and tailor to specific child –sedation plan,prepare child – show room, practice on soft toy

Other sedatives (Paeds)

❖ Propofol : usually only if no ketamine available or CI for ketamine use or in combination with ketamine -Dose related apnoea, hypotension -More SE when compared to ketamine

❖ Fentanyl : 75-125x as potent as morphine peak effect 2mins and duration of action for 20minutes IN > emetogenic

❖ Midazolam : Paradoxical agitation (1-15%) children No analgesic properties

❖ Remifentanil, Sufentanil, alfentanil –no current evidence demonstrating superiority above fentanyl

Special populations

❖ Major co-morbidities/Elderly :Go low, go slow

❖ Obese patient – dose adjustment, positioning (ramping)

❖ Pregnancy- Maxalon/H2 blocker – increased risk reflux - Preprocedural hydration, LLP - Low reserve, rapid desaturation –suppl O2

General complications❖ Aspiration risk : rare but important complication, pH most NB factor, intubation

does not eliminate risk for aspiration

❖ Risk of laryngospasm : rare (0.4%) – PEEP, deepen sedation, full dose sux, IV lignocaine

❖ Hypotension/CVS instability - Fluids, rescue pressor, elevate legs

❖ Hypoventilation – 11% - stimulate! painful - Jaw thrust, nasal airway - BVM - 10bpm! - Consider NIV - Consider LMA - Last resort intubation – very rare

❖ PONV : 5% -Ketamine/opioids - little evidence for prophylactic antiemetics

❖ Emergence (Ketamine) : recovery agitation, dreams, hal-lucinations, depersonalisation – 10-20% adults (1-2% clinically significant), 7.6% children (1.4% significant)-BZD did not decrease incidence as prophylaxis, useful in treatment though-Pre-procedural “prep”- can eliminate emergence

Ketafol❖ Best of both worlds - HD balanced anaesthesia, more rapid

recovery times without increase in adverse effects

❖ Synergism – reduction of individual doses of drugs, safer than individual use – less apnoea, consistent sedation

❖ Ketamine: Analgesia and dissociation, increases HR and BP, stimulates respiratory drive

❖ Propofol: decreases HR and BP, amnesia,antiemetic

❖ 100mg Ketamine, 100mg Propofol in 20mls syringe

❖ 2-3mls aliquots to effect

❖ Laryngospasm and emergence phenomena mitigated by sub-dissociative doses of ketamine

Dexmedetomidine❖ Selective alpha 2 adrenoreceptor agonist

❖ “clonidine” like with sedative properties

❖ During extubation in the ICU - sedation but maintaining respiratory drive, very expensive

❖ “Ketamine” for hypertensive patients

❖ Infusion : 0.5-1mcg/kg for 10mins add fentanyl for analgesia

❖ SE : Bradycardia, hypotension, beware heart blocks Pressors at hand with Glycopyrrolate

❖ New developments : Fospropofol –propofol prodrug

Post procedural care❖ Adequate period of observation until alert, orientated and HD

stable, normal age appropriate vital signs

❖ Standarized recovery protocol advised

❖ Unlikely more than 30mins

❖ Reliable caretaker to observe for post procedural complications

❖ On discharge written and verbal instruction, time and date specific follow up (Parent information sheet)

❖ Oral challenge and independent mobilisation is debatable - talking and sitting up unaided usually sufficient

❖ Advise on risk of operating machinery and complex tasks (driving) and avoidance of alcohol

References❖ Green

SM, Krauss B. Procedural sedation terminology: moving beyond "conscious sedation". Ann Emerg Med 2002; 39:43

❖ Gan TJ. Pharmacokinetic and pharmacodynamic characteristics of medications used for moderate sedation. Clin Pharmacokinet 2006; 45:855.

❖ American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002; 96:1004.

❖ 4 Joint Commission on Accreditation of Healthcare Organizations. Comprehensive Accreditation Manual for Hospitals, The Official Handbood. JCAHO Publication, Chicago 2004.

❖ Krauss B, Green SM. Sedation and analgesia for procedures in children. N Engl J Med 2000; 342:938

❖

Brady M, Kinn S, Stuart P. Preoperative fasting for adults to prevent perioperative complications. Cochrane Database Syst Rev 2003; :CD004423.

❖ Cheung KW, Watson ML, Field S, Campbell SG. Aspiration pneumonitis requiring intubation after procedural sedation and analgesia: a case report. Ann Emerg Med 2007; 49:462.

❖ Sakai T, Planinsic RM, Quinlan JJ, et al. The incidence and outcome of perioperative pulmonary aspiration in a university hospital: a 4-year retrospective analysis. Anesth Analg 2006; 103:94

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Mace SE. Adverse events of emergency department procedural sedation. [abstract] Ann Emerg Med 2006; 48:S5