Ketamine-only Breathing Intubation

The use of ketamine monotherapy – without a paralytic – to facilitate endotracheal intubation (ETI) is an emerging technique that offers pivotal benefits over RSI in specific circumstances (1). Ketamine-only breathing intubation (KOBI) is the use of dissociative-dose ketamine to facilitate intubation in the spontaneously breathing patient. Dissociative-dose ketamine reliably renders the patient impervious to and amnestic of ETI while airway reflexes, respiration, and BP are typically maintained (1).

There is a lack of published experience with KOBI; recommendations for its use are based on expert opinion. However, given growing interest in KOBI, the Emergency Physician should be familiar with this technique. KOBI may be particularly useful in certain patient groups:

• When airways are anatomically difficult. These patients are often managed in elective anesthesia settings via fiberoptic bronchoscopy. KOBI may provide a similar degree of safety to traditional awake flexible endoscopic intubation, does not require additional time or a cooperative patient, and uses laryngoscopy techniques familiar to Emergency Physicians.
  
  
• KOBI may be of benefit for patients who cannot tolerate even a brief period of apnea and thus are at high-risk for peri-intubation decompensation. Such patients include those with a severe oxygenation deficit who saturate < 90% on 100% non-invasive ventilation and profoundly acidemic patients (e.g., DKA, salicylate or toxic alcohol ingestion) who require a very high minute ventilation to compensate for the severe metabolic acidosis.
  
  
• The likelihood of a hypotensive patient to deteriorate during or after intubation is mitigated by an induction that has minimal impact on hemodynamics. Apnea and the transition from negative- to positive-pressure ventilation reduces venous return and, in physiologically marginal patients, may precipitate circulatory collapse. Using a breathing technique during intubation followed by gentle and gradually augmented pressure support afterward may improve outcomes in such critically ill patients.

Dissociated patients may have muscle rigidity, including a clenched jaw, which can typically be mitigated using small doses of a conventional sedative (e.g. midazolam, propofol); however, these adjuncts may also cause hypoventilation or apnea. A fast-acting paralytic (rocuronium or succinylcholine) must be readily available in a syringe when performing KOBI should muscle rigidity occur.

Reference: Merelman AH, et al. West J Emerg Med. 2019 May;20(3):466-471.