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

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