We thank Rubin et al.1 for their thoughtful discourse on the intubateCOVID study reporting emergency airway management in COVID-19 patients.2,3 We welcome the discussion our article has invited. We agree that patients with COVID-19 requiring tracheal intubation are often physiologically compromised, having failed noninvasive means for respiratory support, and that first-pass success is an imperfect outcome measure for assessing risks to patients during tracheal intubation. Their account of the physiologic derangements that can occur with induction of anesthesia and transition to positive pressure ventilation mirrors our own experiences in managing this cohort of patients.4
Our study has limitations with the incomplete patient-level data that may help us truly interpret the physiologic impact of tracheal intubation in this setting. We can, however, infer from these data that physiologic and anatomical difficulty are not mutually exclusive. First-pass success is a surrogate for overall ease of performing the tracheal intubation procedure, and a high or low rate of success in this measure informs the likelihood of encountering delays in securing the airway and prolonged apnea times that would then result in physiologic deterioration. In the event of this deterioration, cessation of tracheal intubation attempts may be prompted in exchange for bag-mask ventilation or cardiovascular stabilization with vasopressor administration. Thus, first-pass success may indeed be a meaningful indicator for physiologically difficult airways. Delving into our data, this may be the underlying reason for rapid sequence induction being associated with an improved first-pass success rate, as abandoning tracheal intubation attempts in exchange for optimizing physiology is less likely. This may dovetail into the discussion of early versus late tracheal intubation attempts, with early intubation potentially associated with greater physiologic stability than late tracheal intubation.4
Ultimately, however, we acknowledge that further studies incorporating patient-level physiologic variables and other outcome measures may be required to investigate particular patient factors to inform airway managers in their approaches to mitigate risk. Although all studies have limitations, we began the pandemic with little or no information, and multicenter collaborative studies such as intubateCOVID have needed to move quickly to provide evidence to inform clinicians and improve the quality of patient care.
Financial support was received from the Difficult Airway Society (London, United Kingdom), the American Society of Anesthesiologists (Schaumburg, Illinois), the International Anesthesia Research Society (San Francisco, California), and the Anesthesia Patient Safety Foundation (Rochester, Minnesota).
The authors declare no competing interests.