The comparison of the relaxant effects of propofol, thiopental, ketamine, and etomidate on isolated rat uterine smooth muscle / 대한마취과학회지

BACKGROUND: Intravenous hypnotics are used in pregnancy, labor and delivery. The aim of the present study was to investigate and compare the relaxant effects of propofol, thiopental, ketamine, and etomidate on isolated rat uterine smooth muscles. METHODS: Uterine smooth muscle preparations were obtained from non-pregnant female rats. The uterus of the rat was dissected and cut into 10 mm strips. The muscle strips were bathed in Krebs solution. After spontaneous uterine contractile activity had been accomplished, propofol, ketamine, thiopental, and etomidate in various concentrations were added cumulatively to the baths and resting tension, active tension, and frequency of contration were recorded at each concentration of agents. EC(5), EC(25), EC(50), EC(75), and EC(95) of each drug on active tension and frequency of contraction were calculated using a probit model. RESULTS: Propofol, thiopental, and etomidate reduced uterine contractions in a concentration-dependent manner. Ketamine concentrations of 10(-7) to 10(-5) M augmented uterine contractions but ketamine concentrations of 10(-4) to 10(-3) M attenuated uterine contractions. The EC(50)'s of propofol, thiopental, ketamine, and etomidate on active tension were 1.56 x 10(-5) M, 4.97 x 10(-5) M, 3.52 x 10(-4) M, and 2.73 x 10(-5) M, respectively. CONCLUSIONS: All four intravenous hypnotics relaxed the uterine smooth muscle of rats except for ketamine in low concentrations (10(-7) to 10(-5) M). Propofol had the greatest relaxant effects on isolated rat uterine smooth muscle among these hypnotics. It seems that ketamine is a suitable obstetric hypnotic agent for hypovolemic parturients and propofol is a useful hypnotic agent for uterine relaxation during pregnancy.

The Comparison of the Effects of Ondansetron, Lidocaine, and Tramadol for the Prevention of Pain on Injection of Rocuronium / 대한마취과학회지

BACKGROUND: Intravenous injection of rocuronium produces intense discomfort at the site of injection in conscious patients. The aim of this study was to compare the effects of intravenous ondansetron, lidocaine, and tramadol for minimizing pain caused by the injection of rocuronium. METHODS: One hundred twenty patients were randomly assigned four groups. Before general anesthesia was induced with thiopental sodium (5 mg/kg), manual occlusion (70 mmHg) with tourniquet of venous inflow was performed. The patients were given saline 4 ml (Group 1, n = 30), ondansetron 8 mg (Group 2, n = 30), lidocaine 60 mg (Group 3, n = 30), or tramadol 50 mg (Group 4, n = 30) diluted into a 4 ml solution. The occlusion was released after 20 seconds and rocuronium was injected over 10 15 seconds. The patients were asked immediately if they had pain in the arm, and the response was assessed. The pain response to rocuronium injection was graded with using Memis' 4-point scale. The side effects were recorded for 24 hours after administration of rocuronium. RESULTS: There were no difference among groups in respect of age, weight, and gender (P < 0.05). Lidocaine reduced the incidence of rocuronium injection pain but ondansetron and tramadol did not (P < 0.05). Ondansetron, lidocaine, and tramadol reduced the severity of rocuronium injection pain (P < 0.05). CONCLUSIONS: I conclude that lidocaine is the most effective among these drugs in the prevention of rocuronium injection pain.