Advertisement

Pro: The Best Induction for the Physiologically Difficult Airway is Ketamine-Propofol Admixture (“Ketofol”)

Published:January 06, 2023DOI:https://doi.org/10.1053/j.jvca.2022.12.036
      THE INDUCTION AND INTUBATION of critically ill patients are high-risk interventions, with nearly half of patients experiencing a major adverse event, such as cardiovascular instability, severe hypoxia, or cardiac arrest.
      • Russotto V
      • Myatra SN
      • Laffey JG
      • et al.
      Intubation practices and adverse peri-intubation events in critically ill patients from 29 countries.
      Preexisting physiologic derangements are a major contributor to decompensation, and the term “physiologically difficult airway” is used to describe patients with significant physiologic alterations prior to airway management.
      • Myatra SN
      • Divatia JV
      • Brewster DJ.
      The physiologically difficult airway: An emerging concept.
      Although many factors may contribute to a patient with a physiologically difficult airway, the derangements of most concern are hypotension, hypoxia, severe metabolic acidosis, and right ventricular dysfunction.
      • Myatra SN
      • Divatia JV
      • Brewster DJ.
      The physiologically difficult airway: An emerging concept.
      Inducing a patient who is already hypotensive can be dangerous, as both the induction agents, as well as positive-pressure ventilation, can worsen hypotension. Risk factors for periintubation hypotension have been explored recently, and one study derived and validated a scoring system for periintubation hypotension in critically ill patients (C-statistic 0.75 [95% CI 0.72-0.78]).
      • Smischney NJ
      • Kashyap R
      • Khanna AK
      • et al.
      Risk factors for and prediction of post-intubation hypotension in critically ill adults: A multicenter prospective cohort study.
      Given the literature surrounding the negative downstream effects of hypotension on the critically ill, one could argue that preventing further decreases in blood pressure is the most important consideration when faced with intubation in a patient with preexisting hypotension. For example, a multicenter cohort study demonstrated that mean arterial pressures ≤65 mmHg in critically ill patients were associated with an increased risk of 30-day major adverse cardiac or cerebrovascular events and increased 30-day mortality. This held true even for hypotension of limited duration.
      • Smischney NJ
      • Shaw AD
      • Stapelfeldt WH
      • et al.
      Postoperative hypotension in patients discharged to the intensive care unit after non-cardiac surgery is associated with adverse clinical outcomes.
      Preexisting hypoxia is also a significant risk factor for decompensation because any apnea time is tolerated poorly by patients with limited arterial oxygen content reserve. Additionally, induction agents typically worsen the ventilation-perfusion mismatch that is already present to some degree in hypoxic patients. Hypoxia, in general, also places patients at greater risk for hemodynamic instability, arrhythmia, and cardiopulmonary arrest.
      • Smischney NJ
      • Kashyap R
      • Khanna AK
      • et al.
      Risk factors for and prediction of post-intubation hypotension in critically ill adults: A multicenter prospective cohort study.
      Severe metabolic acidosis contributes to a physiologically difficult airway, as any apnea time will result in an increased PaCO2 and a worsening acidosis. Preexisting right ventricular dysfunction presents many challenges to intubation, as the rise in PaCO2 with induction will result in increases in pulmonary arterial pressures and right ventricular strain. Additionally, positive-pressure ventilation tends to overall reduce preload and may precipitate cardiovascular collapse due to insufficient preload to a poorly functioning right ventricle. Patients with a physiologically difficult airway may possess one or a combination of these physiologic derangements. Once a physiologically difficult airway is identified, the next challenge for the clinician is to design an induction regimen that would be best tolerated by a patient with preexisting physiologic challenges.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Journal of Cardiothoracic and Vascular Anesthesia
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Russotto V
        • Myatra SN
        • Laffey JG
        • et al.
        Intubation practices and adverse peri-intubation events in critically ill patients from 29 countries.
        JAMA. 2021; 325: 1164-1172
        • Myatra SN
        • Divatia JV
        • Brewster DJ.
        The physiologically difficult airway: An emerging concept.
        Curr Opin Anaesthesiol. 2022; 35: 115-121
        • Smischney NJ
        • Kashyap R
        • Khanna AK
        • et al.
        Risk factors for and prediction of post-intubation hypotension in critically ill adults: A multicenter prospective cohort study.
        PLoS One. 2020; 15e0233852
        • Smischney NJ
        • Shaw AD
        • Stapelfeldt WH
        • et al.
        Postoperative hypotension in patients discharged to the intensive care unit after non-cardiac surgery is associated with adverse clinical outcomes.
        Crit Care. 2020; 24: 682
        • Miller RD
        Miller's Anesthesia.
        7th ed. Churchill Livingstone, Philadelphia, PA2010: 720-721
        • Tarwade P
        • Smischney NJ.
        Endotracheal intubation sedation in the intensive care unit.
        World J Crit Care Med. 2022; 11: 33-39
        • Smischney NJ
        • Nicholson WT
        • Brown DR
        • et al.
        Ketamine/propofol admixture vs etomidate for intubation in the critically ill: KEEP PACE Randomized clinical trial.
        J Trauma Acute Care Surg. 2019; 87: 883-891
        • Hui TW
        • Short TG
        • Hong W
        • et al.
        Additive interactions between propofol and ketamine when used for anesthesia induction in female patients.
        Anesthesiology. 1995; 82: 641-648
        • Sinner B
        • Ketamine Graf BM.
        Handb Exp Pharmacol. 2008; 182: 313-333
      1. Fentanyl [package insert]. Lake Forest, IL: Akorn, Inc; 2012.

        • Chan CM
        • Mitchell AL
        • Shorr AF.
        Etomidate is associated with mortality and adrenal insufficiency in sepsis: A meta-analysis.
        Crit Care Med. 2012; 40: 2945-2953
        • Komatsu R
        • You J
        • Mascha EJ
        • et al.
        Anesthetic induction with etomidate, rather than propofol, is associated with increased 30-day mortality and cardiovascular morbidity after noncardiac surgery.
        Anesth Analg. 2013; 117: 1329-1337
        • Jabre P
        • Combes X
        • Lapostolle F
        • et al.
        Etomidate versus ketamine for rapid sequence intubation in acutely ill patients: A multicentre randomised controlled trial.
        Lancet. 2009; 374: 293-300
        • Bruder EA
        • Ball IM
        • Ridi S
        • et al.
        Single induction dose of etomidate versus other induction agents for endotracheal intubation in critically ill patients.
        Cochrane Database Syst Rev. 2015; 1CD010225
        • Gelissen HP
        • Epema AH
        • Henning RH
        • et al.
        Inotropic effects of propofol, thiopental, midazolam, etomidate, and ketamine on isolated human atrial muscle.
        Anesthesiology. 1996; 84: 397-403
        • Mazzeffi M
        • Johnson K
        • Paciullo C.
        Ketamine in adult cardiac surgery and the cardiac surgery intensive care unit: An evidence-based clinical review.
        Ann Card Anaesth. 2015; 18: 202-209