This was a lecture from the ASA national meeting.
Deciding how to approach an airway should be a straightforward question. The ASA Difficult Airway Algorithm (DAA) lays out a step-by-step approach for awake intubation, Box A, or airway control after induction of anesthesia, Box B. But how does the physician anesthesiologist decide where to begin?
“The Difficult Airway Algorithm is the benchmark for how airways are handled around the world,” said William Rosenblatt, M.D., Professor of Anesthesia at Yale University Medical School, New Haven, Connecticut. “But I have some difficulty with the algorithm. An algorithm should have one entry point, one root node – and the DAA has two root nodes, Box A and Box B. Your first airway management choice is awake intubation versus intubation after induction of anesthesia. How do you make that initial choice?”
Dr. Rosenblatt has created his own decision tree to help trainees and clinicians decide which approach to take for airway management. He explored the approach during the inaugural Society of Airway Management Ovassapian Lecture, “The Airway Approach Algorithm: What Would Andy Say?” on Sunday afternoon.
The lecture is named for Andranik Ovassapian, M.D., anesthesiologist, professor, inventor, teacher and founding member of the Society of Airway Management.
“The goal in anesthesia is always to avoid the emergency pathway that is part of the DAA,” Dr. Rosenblatt said. “We can do that by making the right initial choice between entering the algorithm through Box A or Box B. We need an algorithm to guide us in that choice.”
Dr. Rosenblatt created a list of five questions to direct physician anesthesiologists to the appropriate entry node on the DAA.
Must the Airway be controlled? If the answer is “no,” consider regional or infiltrative anesthesia. If the answer is “yes,” continue to the remaining questions.
Could your laryngoscopy be at all difficult? “This is an assessment of the potential risks of this airway in this patient for this procedure,” Dr. Rosenblatt said. If the answer is “yes,” proceed to Box A. If the answer is “no,” continue to the next question.
One sure way to assess airway risks is to conduct a preoperative endoscopic airway evaluation. Traditional assessments, such as the Mallampatti test, atlanto occipital joint extension and mandibular space, lack sufficient sensitivity, specificity and positive predictive value, he said.
Could your supraglottic ventilation be used if needed? If the answer is “yes,” proceed to the next question. If the answer is “no,” proceed to Box A.
There are more than two dozen supraglottic ventilation devices on the market, Dr. Rosenblatt noted, all of them highly dependent on operator skill. Patient factors such as facial hair, male gender, higher BMI and snoring also affect the likely outcome of ventilation.
Is the stomach empty, i.e., is there an aspiration risk? If the answer is “yes,” proceed to the next question. If the answer is “no,” proceed to Box A.
Will the patient tolerate an apneic period? If the answer is “yes,” proceed to Box A. If the answer is “no,” proceed to Box B.
“This asks the same questions that the ASA asked in creating its algorithm,” Dr. Rosenblatt said. “But it asks them in an algorithmic fashion that gives you a pathway to follow.”