Chapter 8. Pharmacologic Adjuncts to Intubation

Oral endotracheal intubation without pharmacologic assistance should be reserved for the unresponsive and apneic patient. Unconscious patients capable of resisting laryngoscopy or those with spontaneous respiratory effort should be intubated with the assistance of pharmacologic adjuncts. A rapid sequence induction optimizes intubation conditions while minimizing the risk of aspiration for the patient. It can be performed with a high rate of success and minimal complications.1 Rapid sequence intubation requires the use of several pharmacologic adjuncts (Tables 8-1 & 8-2). This includes a potent anesthetic agent to induce unconsciousness and a neuromuscular blocking agent to produce paralysis.

The ideal induction agent has an extremely rapid onset of action, produces predictable deep anesthesia, has a short duration of action, and has no adverse effects.2 Unfortunately, such an agent does not yet exist. However, there are at least six drugs that can safely be used for induction of anesthesia and intubation. These include thiopental, methohexital, etomidate, ketamine, and propofol. Midazolam and fentanyl may also be used alone or in conjunction with the above agents.2 The decision as to which induction agent is the most suitable is largely dependent on the Emergency Physician's experience and his or her understanding of each drug's properties. In this section, each of these drugs is briefly detailed as to its pharmacokinetics, mechanism of action, pharmacodynamics, administration, and adverse effects.

For more than 50 years, barbiturates have been a mainstay in the induction of anesthesia. They rapidly produce sedation and hypnosis in a dose-dependent fashion. They are also less expensive than many of the newer induction agents.3 Because of their high potency, rapid onset, and short duration of action, the most commonly used barbiturates are thiopental (Pentothal™) and methohexital (Brevital™).

Pharmacokinetics

When injected intravenously, these ultra-short-acting barbiturates can produce effects in one arm-brain circulation time, or less than ...