Efficacy of intravenous acetaminophen and lidocaine on propofol injection pain.

BACKGROUND: Different methods and propofol formulations have been used to decrease propofol injection pain, but it remains an unresolved problem. We aimed to investigate the effect of i.v. acetaminophen pretreatment on the propofol injection pain. METHODS: One hundred and fifty ASA I-II patients undergoing general anaesthesia were randomly allocated into three groups. A 20-gauge catheter was inserted into a superficial radial vein of the left hand, and after the occlusion of venous drainage, Groups I, II, and III were pretreated with 40 mg of lidocaine in saline, 50 mg of i.v. acetaminophen, and 5 ml of saline, respectively. The occlusion was released after 2 min and one-fourth of the total propofol dose was injected into the vein over a period of 5 s. During the injection of both pretreatment solution and propofol, patients' pain was assessed and recorded as 0-3, corresponding to no, mild, moderate or severe pain, respectively. Chi2 and Kruskal-Wallis tests were used for the statistical analysis. For all analyses, differences were considered to be significant at P<0.05. RESULTS: Patient characteristics were similar among the groups. Incidence of pain on injection of propofol in control, i.v. acetaminophen, and lidocaine groups was 64%, 22% and 8%, respectively (P<0.05). CONCLUSIONS: Pretreatment with i.v. acetaminophen seems to be effective in attenuating pain during i.v. injection of propofol.

Comparison of dexmedetomidine-propofol vs. fentanyl-propofol for laryngeal mask insertion.

BACKGROUND AND OBJECTIVES: There have been many studies to find the optimum anaesthetics to provide excellent conditions for laryngeal mask insertion. We compared the effects of dexmedetomidine administered before propofol, on laryngeal mask insertion with fentanyl combined with propofol. METHODS: In all, 52 patients, ASA I-II, scheduled to have minor urological procedures were randomized into two groups. Group F received 1 microg kg(-1) fentanyl (in 10 mL normal saline) and Group D received 1 microg kg(-1) dexmedetomidine (in 10 mL normal saline). We used 1.5 mg kg(-1) propofol for induction and 50% N2O and 1.5% sevoflurane in oxygen for maintenance. We observed jaw mobility (1: fully relaxed; 2: mild resistance; 3: tight but opens; 4: closed), coughing or movement (1: none; 2: one or two coughs; 3: three or more coughs; 4: bucking/movement) and other events such as spontaneous ventilation, breath holding, expiratory stridor and lacrimation. In each category, scores <2 were acceptable for laryngeal mask insertion. RESULTS: More patients developed apnoea and their apnoea times were longer in Group F than Group D (P < 0.001). Respiratory rates increased in Group D (P < 0.001). Adverse events during laryngeal mask insertion were similar. The reductions in systolic and mean blood pressures were greater in Group F (systolic: P < 0.05, mean: P < 0.01). Emergence times were shorter in Group F than in Group D (P < 0.001). CONCLUSION: Dexmedetomidine, when used before propofol induction provides successful laryngeal mask insertion comparable to fentanyl, while preserving respiratory functions more than fentanyl.

Renal safety and extrahepatic defluorination of sevoflurane in hepatic transplantations.

BACKGROUND: The main metabolic pathway for defluorination of sevoflurane in the liver produces inorganic fluoride (Fl). The metabolism and effect of sevoflurane on the kidney is not clear during anhepatic phase in liver transplantation. The goal of the present study was to investigate the metabolism and renal effect of sevoflurane by measuring plasma and urine inorganic fluoride, urinary N-acetyl-glucosaminidase (NAG), and plasma creatinine levels in patients undergoing liver transplantations. METHODS: After institutional approval and informed consent, we studied nine cases of orthotopic liver transplantation after anesthesia was induced with 5 mg . kg(-1) thiopental, 1 mug . kg(-1) fentanyl intravenously, the trachea was intubated after vecuronium bromide 0.1 mg . kg(-1). Anesthesia was maintained with sevoflurane (2%), O(2), and N(2)O at a total gas flow of 6 L . min(-1) using a semiclosed circle system with a sodalime canister. Blood and urine samples were obtained to measure plasma and urine fluoride concentrations and urinary NAG excretions before induction (P0), hourly during resection (P1, P2, P3), every 15 minutes during anhepatic phase (A1, A2, A3), hourly after reperfusion (neohepatic phase) (N1, N2, N3), and postoperative first hour (Po1). Preoperative (T0) and postoperative day 1 (T1), 3 (T3), 7 (T7) plasma blood urea nitrogen (BUN) and creatinine (Cr) levels were also recorded. RESULTS: Mean duration of surgery was 9:06 +/- 0:09 hours. Mean inorganic fluoride concentrations in plasma were in the range of 0.71 +/- 0.30 to 28.73 +/- 3.31 mumole . L(-1). In P3, N1, N2, N3, increases in plasma inorganic fluoride concentrations were significant (P < .05) and reached a peak value at Po1. The mean urine inorganic fluoride concentrations were 12.49 +/- 2.04 to 256.7 +/- 49.62 mumole . L(-1). In A2, A3, N1, N2, and N3, mean urine inorganic fluoride concentrations were significantly increased (P < .05) and the peak value was observed at Po1. Mean NAG concentrations in urine varied (5.6 +/- 1.6 IU . L(-1) to 12.5 +/- 1.14 IU . L(-1)) and peak level was observed at 30 minutes of the anhepatic phase (A2), which did not exceed the normal values for urine NAG levels (1.5 to 6.1 U . L(-1)). No impairment was observed in serum BUN and creatinine levels at any time. While there was only a slight increase in NAG during anhepatic phase, there was no change in plasma F1. CONCLUSIONS: Sevoflurane seemed to have minimal effect on kidney functions of BUN and Cr levels during liver transplantation. Although urine F1 and NAG levels increased during the anhepatic phase plasma F1, BUN, and Cr levels did not, suggesting that renal F1 production may occur in the absence of hepatic function. The renal effect of sevoflurane in chronic liver disease is controversial and must be investigated in further studies.

The effect of inhalational anaesthetics on QTc interval.

BACKGROUND AND OBJECTIVE: The aim of this study was to assess time dependent cumulative effects of three different inhalation anaesthetics on QTc interval during the maintenance of anaesthesia. METHOD: Seventy-five ASA I-II male patients undergoing inguinal herniorrhaphy were randomly allocated into three groups. No premedication was given. Anaesthesia was induced with thiopental and tracheal intubation was facilitated by vecuronium in all groups. Anaesthesia was maintained with 0.8% halothane (Group I) (n = 25), 1% isoflurane (Group II) (n = 25), or 2% sevoflurane (Group III) (n = 25) and 66% nitrous oxide in oxygen. Three lead electrocardiogram recordings were taken before induction, 2, 5, 10, 15, 30 and 45 min after induction and after extubation. Heart rate, systolic, diastolic, mean arterial pressure and SpO2 were recorded at the same time. Heart rate and corrected QT interval were evaluated by using Bazett's formula. Multivariate analysis of variance for repeated measures was used to determine intergroup and intragroup differences. RESULTS: There was no statistically significant difference in the baseline QTc values of the groups. There was no difference between QTc values with halothane and sevoflurane. There was a difference between QTc values with isoflurane and those with the other two inhalation anaesthetics (P < 0.05). Although QTc values in the isoflurane group were higher at all times, the critical value of 440 ms was not exceeded. CONCLUSION: We conclude that halothane 0.8%, isoflurane 1% and sevoflurane 2% do not prolong QTc interval.

Anesthesia in Beckwith-Wiedemann syndrome.

Anesthetic management of a 3-month-old boy with Beckwith-Wiedemann syndrome for bronchoscopy is reported. Management may be complicated by a difficult airway, congenital heart disease, and hypoglycemia. We did not have difficulty in airway management either with tracheal intubation or rigid bronchoscopy, but we could not extubate the baby because of tracheomalacia.

Perioperative effects of melatonin and midazolam premedication on sedation, orientation, anxiety scores and psychomotor performance.

BACKGROUND AND OBJECTIVE: To compare the perioperative effects of melatonin and midazolam given in premedication, on sedation, orientation, anxiety scores and psychomotor performance. METHODS: Exogenous administration of melatonin not only facilitates the onset of sleep but also improves its quality. A prospective, randomized, double-blind, placebo-controlled study was performed in 66 patients undergoing laparoscopic cholecystectomy. Patients were given melatonin 5 mg, midazolam 15 mg or placebo, 90 min before anaesthesia, sublingually. Sedation, orientation and anxiety were quantified before; 10, 30, 60 and 90 min after premedication; and 15, 30, 60 and 90 min after admission to the recovery room. Neurocognitive performance was evaluated at these times, using the Trail Making A and B and Word Fluency tests. The differences between the groups were analysed by ANOVA. Two-way comparisons were performed by Scheffé analysis. Sedation and amnesia were analysed by the chi2 test. RESULTS: Patients who received premedication with either melatonin or midazolam had a significant increase in sedation and decrease in anxiety before operation compared with controls. After operation, there was no difference in sedation scores of all groups. Whereas, 30, 60 and 90 min after premedication the melatonin and midazolam groups exhibited a significantly poorer performance in Trail Making A and B tests compared with placebo, there were no significant differences among the groups in terms of neuropsychological performance after the operation. Amnesia was notable only in the midazolam group for one preoperative event. CONCLUSION: Melatonin premedication was associated with preoperative anxiolysis and sedation without postoperative impairment of psychomotor performance.