Updates from the Physiologically Difficult Airway Task Force: Delphi Consensus Summary

In October of 2020, SOCCA formed a task force to champion the cause of physiologically difficult airway (PDA) management. As is familiar to critical care anesthesiologists, in the contemporary era of airway management the physiologic challenges posed by patients requiring tracheal intubation outside of the operating room with, for example, right ventricular failure, cardiovascular instability, or severe hypoxemia, often surpass the technical challenges associated with intubation itself. This clinical gestalt has been increasingly supported over time by large-scale observational studies, including INTUBE and INTUPROS. As an organization composed of experts in applied complex cardiopulmonary physiology, SOCCA and its membership were well-positioned to make substantive contributions.

A critical mass of literature has amassed over time such that we now have practical, evidenced-based strategies to help inform PDA management in certain aspects, such as optimizing pre-oxygenation. However, the literature remains lacking in many other critically important aspects. Along those lines, SOCCA’s PDA Task Force identified an opportunity to develop expert consensus informed by a robust Delphi methodology to fill in these gaps, better inform practice, and identify areas for future research.

The PDA Task Force first conducted a literature review to identify clinical domains relevant to PDA management: definition/risk factors, team preparation and human factors, patient preparation and optimization, performing the procedure, and post-intubation care. Within these domains, Task Force members identified topics and questions key to clinical management, for which many have absent or limited evidence to inform best practice. The Task Force chartered a steering committee for the consensus effort, recruited an international expert panel, developed a survey tool, and then over seven Delphi rounds in 2023 identified areas of expert consensus and dissensus regarding PDA management.

The results of this effort were recently published in Intensive Care Medicine. A key point that emerged was an expert consensus definition of a PDA: one in which the patient’s physiological and pathophysiological alterations increase the risk for complications during tracheal intubation and the transition to positive pressure ventilation. Hypoxemia, cardiovascular instability, right ventricular dysfunction, and increased intracranial pressure were felt to represent relevant pathophysiological alterations, whereas obesity and pregnancy were felt to represent relevant physiological alterations.

Key points for emphasis in different facets of clinical management are summarized below.

It is also important to emphasize that dissensus and/or disagreement among experts was also identified in several areas, including: the definition of an experienced airway operator, the role and management of cricoid pressure, the optimal video laryngoscope design (e.g., conventional versus hyperangulated), and the importance of routinely reversing neuromuscular blocking agents after tracheal intubation. Apart from these domains, the need to further appraise interventions to prevent cardiovascular collapse—the most common physiologic complication associated with tracheal intubation in critically ill adults—emerged as an important area for future research as current evidence is markedly lacking to adequately inform our clinical practice. Work will also be needed to further bridge the implementation gap between identified best practices and the bedside, including identifying barriers to the universal availability and application of video laryngoscopy in this patient population, developing optimal approaches to the application of point-of-care ultrasound, PDA curriculum development, and adaptation to resource limited environments.

On behalf of SOCCA’s PDA Task Force, we would like to extend a token of thanks to all SOCCA members who made this work possible, including Task Force members and those who participated as experts in the consensus effort.