Airway management in critically ill patients involves the identification and management of the potentially difficult airway in order to avoid untoward complications. This focus on difficult airway management has traditionally referred to identifying anatomic characteristics of the patient that make either visualizing the glottic opening or placement of the tracheal tube through the vocal cords difficult. This paper will describe the physiologically difficult airway, in which physiologic derangements of the patient increase the risk of cardiovascular collapse from airway management. The four physiologically difficult airways described include hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure. The emergency physician should account for these physiologic derangements with airway management in critically ill patients regardless of the predicted anatomic difficulty of the intubation.

Introduction: Airway management in the critically ill is associated with a high prevalence of failed first attempts and adverse events which negatively impacts patient care. The purpose of this investigation is to describe an airway continuous quality improvement (CQI) program and its effect on the safety of rapid sequence intubation (RSI) in the emergency department (ED) over a 10-year period.

Methods: An airway CQI program with an ongoing airway registry was initiated in our ED on July 1, 2007 (Academic Year 1) and continued through June 30, 2017 (Academic Year 10). Data were prospectively collected on all patients intubated in the ED during this period using a structured airway data collection form. Key data points included method of intubation, drugs and devices used for intubation, operator specialty and level of training, number of intubation attempts, and adverse events. Adult patients who underwent RSI in the ED with an initial intubation attempt by emergency medicine (EM) resident were included in the analysis. The primary outcome was first pass success which was defined as successful tracheal intubation with a single laryngoscope insertion. The secondary outcome was the prevalence of adverse events associated with intubation. Educational and clinical interventions were introduced throughout the study period with the goal of optimizing these outcomes. Data were analyzed by academic year and are reported descriptively with 95% confidence intervals (CI) of the difference of means.

Results: EM residents performed RSI on 342 adult patients during Academic Year 1 and on 445 adult patients during Academic Year 10. Over the 10-year study period, first pass success increased from 73.1% to 92.4% (difference = 19.3%, 95% CI 14.0% to 24.6%). The percentage of patients who experienced an adverse event associated with intubation decreased from 22.5% to 14.4% (difference = -7.9%, 95% CI -13.4% to -2.4%). The percentage of patients with first pass success without an adverse event increased from 64.0% to 80.9% (difference = 16.9%, 95% CI 10.6% to 23.1%).

Conclusion: The use of an airway CQI program with an ongoing airway registry resulted in a substantial improvement in the overall safety of RSI in the ED as evidenced by an increase in first pass success and a decrease in adverse events.

Introduction: The goal of emergency airway management is first pass success without adverse events (FPS-AE). Anatomically difficult airways are well appreciated to be an obstacle to this goal. However, little is known about the effect of the physiologically difficult airway with regard to FPS-AE. This study evaluates the effects of both anatomically and physiologically difficult airways on FPS-AE in patients undergoing rapid sequence intubation (RSI) in the emergency department (ED).

Methods: We analyzed prospectively recorded intubations in a continuous quality improvement database between July 1, 2014–June 30, 2018. Emergency medicine (EM) or emergency medicine/pediatric (EM-PEDS) residents recorded patient, operator, and procedural characteristics on all consecutive adult RSIs performed using a direct or video laryngoscope. The presence of specific anatomically and physiologically difficult airway characteristics were also documented by the operator. Patients were analyzed in four cohorts: 1) no anatomically or physiologically difficult airway  characteristics; 2) one or more anatomically difficult airway characteristics; 3) one or more physiologically difficult airway characteristics; and 4) both anatomically and physiologically difficult airway characteristics. The primary outcome was FPS-AE. We performed a multivariable logistic regression analysis to determine the association between anatomically difficult airways or physiologically difficult airways and FPS-AE.

Results: A total of 1513 intubations met inclusion criteria and were analyzed. FPS-AE for patients without any difficult airway characteristics was 92.4%, but reduced to 82.1% (difference = - 10.3%, 95% confidence interval (CI), - 14.8% to - 5.6%) with the presence of one or more anatomically difficult airway characteristics, and 81.7% (difference = - 10.7%, 95% CI, - 17.3% to - 4.0%) with the presence of one or more physiologically difficult airway characteristics. FPS-AE was further reduced to 70.9% (difference = - 21.4%, 95% CI, - 27.0% to - 16.0%) with the presence of both anatomically and physiologically difficult airway characteristics. The adjusted odds ratio (aOR) of FPS-AE was 0.37 [95% CI, 0.21 - 0.66] in patients with anatomically difficult airway characteristics and 0.36 [95% CI, 0.19 - 0.67] for patients with physiologically difficult airway characteristics, compared to patients with no difficult airway characteristics. Patients who had both anatomically and physiologically difficult airway characteristics had a further decreased aOR of FPS-AE of 0.19 [95% CI, 0.11 - 0.33].

Conclusion: FPS-AE is reduced to a similar degree in patients with anatomically and physiologically difficult airways. Operators should assess and plan for potential physiologic difficulty as is routinely done for anatomically difficulty airways. Optimization strategies to improve FPS-AE for patients with physiologically difficult airways should be studied in randomized controlled trials.