Emergency War Surgery NATO Handbook: Part III: General Considerations of Wound Management: Chapter XV: Anesthesia and Analgesia
United States Department of Defense
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Succinylcholine is the most commonly used relaxant for rapid sequence intubation, although appropriate doses of non-depolarizing agents will also provide good intubating conditions reasonably quickly. Intravenous injection is followed by fasciculations and muscle cramps and after one minute a flaccid paralysis that requires ventilatory support and has a duration of 5-15 minutes. This drug may cause hyperkalemia in patients with burn or crush injuries but is usually safe in the acute injury situation and for the first several days post-injury. Hyperkalemia, cardiac arrythmia and arrest can occur in these patients after 48 hours and in patients with renal failure, spinal cord injuries, and severe sepsis. One must be aware that this drug can produce a rise in intraocular pressure, and (rarely) vomiting and aspiration secondary to abdominal muscle contraction, bradycardia, salivation, postoperative muscle pain, malignant hyperthermia, and prolonged apnea.
Pancuronium produces an atropine-like tachycardia that is normally not a problem in the young and healthy trauma patient, but may confuse the differential diagnosis of a rapid heart rate intraoperatively. This drug has an onset of paralysis in three minutes and a duration of forty minutes or longer. The initial dose for adults is 0.04-0.1 mg/kg intravenously.
D-Tubocurarine can cause significant histamine release and a resultant hypotension, which limits its usefulness in the hypovolemic patient. D-Tubocurarine and Pancuronium usually need to be reversed by neostigmine or edrophonium in combination with an anticholinergic drug intravenously.
Atracurium and Vecuronium are newer, short-acting, non-depolarizing muscle relaxants which have an onset time of 2-3 minutes and a duration of 20-40 minutes. These drugs can be used by single injection for short procedures or as a continuous infusion. These agents are not vagolytic and do not support the tachycardia or hypertension seen with pancuronium. They can be used to replace succinylcholine for rapid-sequence intubation. These drugs are metabolized by routes other than the kidney and therefore are useful in renal failure patients. Atracurium can cause a small amount of histamine release, but this is usually not hemodynamically significant. Vecuronium is relatively free of cardiovascular side effects. The usual dose of vecuronium is 0.1 mg/kg; and for atracurium 0.3-0.4 mg/kg intravenously.
Use of a nerve stimulator to monitor the degree of neuromuscular blockade will facilitate the management of muscle relaxants and should be considered standard procedure.
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