Extubation Assessment in the ICU

OVERVIEW

The criteria used to assess a patient to determine whether they are ready for extubation is complex and multi-factorial.

  • Ventilator weaning and extubating are two distinct processes
  • Identifying patients for extubation based solely on clinical gestalt is inaccurate
  • Predicting patient readiness is based upon many different physiologic variables
  • No single parameter can accurately predict which patients are ready to resume spontaneous breathing

OPTIMAL RATE OF FAILED EXTUBATION

  • About 15% of patients overall fail extubation in ICU
  • the optimal rate is unknown, but is probably 5-10%
  • higher rates are likely to lead to unnecessary prolongation of intubation at the population level

APPROACH

  • determine disease resolution and consider other factors
  • identify candidates for spontaneous breathing trial
  • perform spontaneous breathing trial
  • identify candidates for extubation
  • extubation and post-extubation care

1. DETERMINE DISEASE RESOLUTION

Begins with the resolution of respiratory failure and/or the disease that prompted initiation of mechanical ventilation

  • Criteria to define disease resolution are not defined nor prospectively validated

A systemic approach emphasising objective surrogate markers of recovery:

A+B

  • Adequate oxygenation and gas exchange
  • PaO2 >60mmHg on FiO2 <40%
  • PEEP 5–8cmH2O
  • CXR stable or improving

C

  • absent or only low dose vasopressors/inotropes
  • with SBP>90mmHg or MAP>60mmHg
  • Stable cardiac rhythm
  • No tacycardia
  • No evidence of myocardial ischemia

D

  • Adequate mentation
  • Rousable (this is controversial: some advise GCS>8 equivalent, some able to follow commands, some neither!)
  • No continuous sedative infusion or neuromuscular blockade
  • no significant weakness (e.g. can lift head off pillow, raise arms in air for 15 seconds, clap hands)
  • pain controlled

E

  • No significant acidosis
  • No electrolytes disturbance (e.g. normal K, PO4 >0.4)
  • adequate fluid status (not overloaded)

F G

  • abdominal pain/ distention controlled
  • tolerating feeds
  • Adequate hemoglobin
  • Afebrile/ sepsis controlled

H I Consider other factors:

  • difficulty of intubation
  • need for further procedures
  • skill level of junior staff in unit overnight
  • time of day

2. IDENTIFY CANDIDATES IN THE ICU FOR A SPONTANEOUS BREATHING TRIAL (SBT)

3. PERFORM SPONTANEOUS BREATHING TRIAL

4. IDENTIFY PATIENTS READY FOR TRIAL OF EXTUBATION

  • Indices to reliably predict extubation do not exist!

Key questions

  • Awake or easily rousable?
  • Able to follow commands?
  • Minimal volume of respiratory secretions?
  • Intact gag and cough reflex to prevent aspiration? (absent gag is normal in many people)

Consider a cuff leak test to check for laryngeal oedema:

  • Laryngeal edema reported in as many as 40% of prolonged intubations
  • 5% patients experience severe upper airway obstruction following extubation
  • can be detected by ‘cuff leak’ test
  • see Cuff Leak Test

Remember to consider other factors:

  • difficulty of intubation
  • need for further procedures
  • skill level of junior staff in unit overnight
  • time of day

5. EXTUBATION AND POST-EXTUBATION CARE

  • Monitor closely for Laryngospasm and Post-extubation stridor — reintubation is not always need
  • Consider high flow nasal prongs or non-invasive ventilation to treat or prevent post-extubation respiratory failure

References and Links

litfl.com

Journal articles and textbooks

  • El-Khatib MF, Bou-Khalil P. Clinical review: liberation from mechanical ventilation. Crit Care. 2008;12(4):221. doi: 10.1186/cc6959. Epub 2008 Aug 6. Review. PubMed PMID: 18710593; PubMed Central PMCID: PMC2575571.
  • King CS, Moores LK, Epstein SK. Should patients be able to follow commands prior to extubation? Respir Care. 2010 Jan;55(1):56-65. Review. PubMed PMID: 20040124.
  • Krinsley JS, Reddy PK, Iqbal A. What is the optimal rate of failed extubation? Crit Care. 2012 Feb 20;16(1):111. doi: 10.1186/cc11185. Review. PubMed PMID: 22356725; PubMed Central PMCID: PMC3396264.
  • Macintyre NR. Evidence-based assessments in the ventilator discontinuation process. Respir Care. 2012 Oct;57(10):1611-8. Review. PubMed PMID: 23013898. [Free Fulltext]
  • Siner JM, Manthous CA. Liberation from mechanical ventilation: what monitoring matters? Crit Care Clin. 2007 Jul;23(3):613-38. Review. PubMed PMID: 17900486.

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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