A single small dose of ketamine prevents lung injury following hepatic ischemia-reperfusion in rabbits.

BACKGROUND: Previous studies demonstrated that large-dose ketamine alleviated lipopolysaccharide-induced lung injury. We investigated whether a single small dose of ketamine could attenuate lung injury induced by hepatic ischemia-reperfusion (HIR) and, if so its underlying mechanisms. METHODS: Thirty male New Zealand rabbits were randomized into three groups (n = 10 each): sham group (Group S), control group (Group C), and ketamine group (Group K). In Group S, hepatic portal vein (HPV) and inferior vena cava (IVC) were left unclamped and 0.9% saline 1 mL/kg was given intravenously. In Group K, ketamine 0.5 mg/kg (0.5 mg/mL) was given intravenously 10 minutes before cross-clamping of the HPV and the IVC. In Group C, 0.9% saline was given 10 minutes before the cross-clamping. The HPV and the IVC were cross-clamped with bulldog clamps and unclamped 60 minutes later in the Group K and the Group C. Blood pressure and pulse rate were recorded throughout the procedure. Rabbits were sacrificed 6 hours postoperatively. Lung W/D ratio was calculated and expression of tumor necrosis factor-α mRNA, intracellular adhesion molecule-1 mRNA, and nuclear factor kappa B (NF-κB)/p65 were quantitatively analyzed. Accumulation of neutrophils in lung tissues was also observed. RESULTS: Small dose of ketamine alleviated the pulmonary edema, but not the systemic hypotension, induced by cross-clamping of the IVC and the HPV. Pretreatment with ketamine significantly reduced the increments of tumor necrosis factor-α mRNA, intracellular adhesion molecule-1 mRNA, and NF-κB/p65; and inhibited the aggregation of neutrophils in lung tissues following HIR. CONCLUSION: 0.5 mg/kg ketamine pretreatment showed significant protective effect on acute lung injury induced by HIR, which might be mediated by the NF-κB pathway.

Neuromuscular block with vecuronium reduces the rapidly extracted auditory evoked potentials index during steady state anesthesia.

PURPOSE: During clinical monitoring, vecuronium appeared to reduce the rapidly extracted auditory evoked potentials index (A-line ARX index or AAI) to some extent. A prospective and randomized study was designed to analyze this phenomenon. METHODS: Forty adult patients undergoing elective surgery were studied. After tracheal intubation, anesthesia was maintained with an end-tidal isoflurane concentration (F(ET)ISO) of 1.0% for 20 min, then a 10-mL dose of either vecuronium 0.05 mg*kg(-1), 0.1 mg*kg(-1), 0.2 mg*kg(-1) or saline was administered in a randomized, double-blind design. The AAI and bispectral index (BI(hx)) were monitored throughout the study and analyzed off-line. RESULTS: BI(hx) was unaltered after the administration of saline or vecuronium. The mean of the averaged (per patient) AAI values recorded from two minutes to ten minutes after the administration of saline or vecuronium 0.05 mg*kg(-1) did not differ significantly from the corresponding mean recorded from 15 min to 20 min after F(ET)ISO maintained 1.0% (P = 0.678, 0.169), however after the administration of vecuronium 0.1 mg*kg(-1) or 0.2 mg*kg(-1), AAI was reduced from 18.3, 18.0 to 14.8, 13.4 (P = 0.016, 0.017). CONCLUSIONS: Neuromuscular block with vecuronium reduces AAI in patients during steady state anesthesia without surgical stimuli, while BI(hx) is unaltered. The cut-off values of AAI for events should be determined according to the level of neuromuscular blockade when monitoring the depth of anesthesia/sedation.

Selection of neuromuscular blocking agents in patients undergoing renal transplantation under general anesthesia.

OBJECTIVE: To study the pharmacodynamics of vecuronium,atracurium, mivacurium and rocuronium in patients with end-stage renal failure. METHODS: Forty-six patients with end-stage renal failure scheduled for renal transplantation and 53 patients with normal renal function were given either vecuronium, atracurium, mivacurium or rocuronium. The neuromuscular effects were monitored by the evoked response of the adductor pollicis to train-of-four stimulation of the ulnar nerve. RESULTS: Onset of vecuronium, atracurium and mivacurium occurred faster or tended to be faster in patients with end-stage renal failure, but there was no significant difference in onset by rocuronium between the control patients and renal failure patients. Furthermore, the no-response period, duration of action and recovery of atracurium did not differ between the two groups. There was no significant difference in duration of action or recovery of mivacurium between the two groups, whereas its no-response period was significantly prolonged in the patients with end-stage renal failure. There was no difference in no-response period or duration of action after the initial dose of vecuronium or rocuronium between the two groups. However, no-response period and duration of effect by vecuronium and rocuronium were prolonged with increasing incremental doses in patients with end-stage renal failure. CONCLUSIONS: All four muscle relaxants could be safely used in patients with end-stage renal failure. Onset of the relaxants were, in some cases, accelerated and no-response period of mivacurium was prolonged in patients with end-stage renal failure undergoing dialysis therapy. End-stage renal failure prolonged the no-response period and duration of action of vecuronium and rocuronium after repeated incremental doses, but did not alter those attributed to atracurium.