Apnea After Low-Dose Ketamine Sedation During Attempted Delayed Sequence Intubation

Some patients are agitated and unable to tolerate conventional preoxygenation methods, including face mask oxygen or noninvasive positive-pressure ventilation. Sedation with ketamine for preoxygenation, also known as delayed sequence intubation, is a technique that can be used to achieve preoxygenation in this patient population. No complications of delayed sequence intubation have previously been reported. A 60-year-old woman presented with acute hypoxic respiratory failure. Despite application of high-flow oxygen (60 L/min) with a nonrebreather face mask, her oxygen saturation remained at 93%. She would not accept a noninvasive positive-pressure ventilation mask, although she remained alert, with vigorous respiratory effort. She received 25 mg of intravenous ketamine (0.31 mg/kg) to allow application of noninvasive positive-pressure ventilation. One minute after receiving ketamine, she developed apnea; bag-valve-mask ventilation was initiated, and she received succinylcholine and etomidate and was intubated on the first attempt, without complication. She had no respiratory effort between the onset of apnea and pharmacologic paralysis. Apnea can occur in critically ill patients who receive ketamine to facilitate preoxygenation. Sedation remains a valuable technique to enable optimal preoxygenation in agitated patients; however, clinicians should not perform this technique lightly and should be prepared to secure the patient's airway immediately.