British journal of anaesthesia
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Tetanic stimulation influences subsequent neuromuscular responses. In addition, the tetanus-induced changes in neuromuscular responses differ according to the level of neuromuscular block at which tetanic stimulation is delivered. We studied the tetanus-induced effect on subsequent train-of-four (TOF) responses at various levels of vecuronium-induced neuromuscular block in 45 anaesthetized patients. ⋯ Maximum post-tetanic percentage increases in TOF responses in groups 1, 2 and 3 were 257 (SD 119)%, 107 (75)% and 68 (54)% for T1/T0 (P < 0.001 for group 1 vs 2; P < 0.001 for group 1 vs 3) and 535 (259)%, 421 (213)% and 292 (171)% for T4/T1 (P < 0.01 for group 1 vs 3), respectively. Durations of post-tetanic increases in TOF responses in groups 1, 2, and 3 were 52 (19) s, 37 (14) s and 32 (13) s for T1/T0 (P < 0.05 for group 1 vs 2; P < 0.01 for group 1 vs 3) and 53 (17) s, 46 (15) s and 35 (12) s for T4/T1 (P < 0.05 for group 1 vs 3), respectively. These data suggest that the tetanus-induced effect on subsequent TOF is more apparent and lasts longer at greater degrees than at lesser degrees of neuromuscular block.
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We have measured haemodynamic responses to induction of anaesthesia, laryngoscopy and intubation in 103 mild-moderate hypertensive patients (83 patients (diastolic pressures < or = 110 mm Hg) currently receiving one of four monotherapies (ACE inhibitors, group A; beta adrenoceptor blocking drugs, group B; calcium channel antagonists, group C; diuretics, group D) and 24 were untreated hypertensive patients). Anaesthesia was induced with fentanyl 1.5-2.0 micrograms kg-1 and thiopentone 3-5 mg kg-1. Tracheal intubation was facilitated by vecuronium 0.1 mg kg-1 and anaesthesia maintained with enflurane and nitrous oxide in oxygen. ⋯ CO was unaltered. Similar changes occurred in the untreated hypertensive patients, although nine of 24 patients exhibited HR > or = 100 beat min-1 after laryngoscopy and intubation. Comparison of the changes in SAP, DAP, CO and SVR with time showed no differences in the five treatment groups; changes in HR were significantly less in group B compared with the other groups (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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We have evaluated in 10 anaesthetized patients the time course of action, infusion requirements, reversibility and pharmacokinetics of Org 9487. Org 9487 was administered as a bolus dose of 1.5 mg kg-1, followed by an infusion to maintain a block of 75-85% for 60 min. After recovery from the bolus dose, a mean dose of Org 9487 3.4 (SD 1.0) mg kg-1 h-1 was administered to maintain a mean neuromuscular block of 83 (3)%. ⋯ The concentration of the 3-OH metabolite remained relatively low. Urinary excretion of Org 9487 and its metabolites was 22% in 24 h. In conclusion, a 1-h infusion of the short-acting drug Org 9487 changed its time course characteristics gradually from that of a short-acting neuromuscular blocking agent to that of a neuromuscular blocker with an intermediate duration of action.