This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lennon, R. L. Articles by Rudd, G. D. Search for Related Content PubMed PubMed Citation Articles by Lennon, R. L. Articles by Rudd, G. D.

Doxacurium Chloride for Neuromuscular Blockade before Tracheal Intubation and Surgery during Nitrous Oxide-Oxygen-Narcotic-Enflurane Anesthesia

Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota and the Department of Clinical Neurosciences, Burroughs Wellcome Co., Research Triangle Park, North Carolina.

Abstract

The neuromuscular effects of doxacurium (BW A938W were studied in 36 patients, divided into four groups of 9 patients each, given doxacurium either 50 fig/kg (2 x ED₉₅) 5 or 4 minutes or 80 µg/kg (3 x ED₉₅) 4 or 3 minutes before tracheal intubation. Adequate neuromuscular relaxation permitted successful intubation at 5 minutes for doxacurium 50 µg/kg and at 4 minutes for 80 µg/kg. Time to 90% blockade was 5.4 ± 1.5 minutes for doxacurium 50 µg/kg and 3.5 ± 1.2 minutes for 80 µg/kg. Time to 25% spontaneous recovery was 84.7 ± 54.3 minutes for doxacurium 50 µg/kg and 164.4 ± 85.2 minutes for 80 µg/ kg. Either neostigmine 45 tiglkg, neostigmine 60 µg/kg, or edrophonium 1000 µg/kg was given for reversal when T1 had spontaneously recovered to 25% of baseline level, T1 being the first response to repetitive train-of-four (TOF) stimuli (2 Hz for 2 seconds at 10-second intervals) expressed as percent of baseline level. The T4:T1 ratio is the amplitude of the fourth twitch relative to the first twitch in a TOF stimulus expressed as a ratio. Tl rapidly achieved 90% of baseline in 5–10 minutes after reversal of neuromuscular blockade. In contrast, the T4:T1 ratio lagged, recovering to a mean of 0.6 at 20 minutes when T1 was over 90% of baseline. Recovery patterns were not statistically significantly different (unpaired t-test) among the three reversal regimens. Therefore, the reversal data were pooled. No clinically significant hemodynamic effects occurred in any group. The authors conclude that doxacurium is a long-acting muscle relaxant that provides excellent intubating conditions within 5 minutes with 50 uglkg and within 4 minutes with 80 fig/kg. Neuromuscular blockade lasts approximately 85 and 164 minutes, respectively. The neuromuscular blockade is pharmacologically readily reversible.

Key Words: NEUROMUSCULAR RELAXANTS—doxacurium