Effects of oral clonidine premedication on haemodynamic response to laryngoscopy and tracheal intubation: a clinical trial.

The objective of this study was to evaluate the efficacy of pre-anesthetic orally administration of clonidine on pulse rate and blood stress response to laryngoscopy and tracheal intubation. In a double-blinded, randomized study, 274 ASA I and II subjects with age of 18 to 45 years scheduled for elective surgery under general anesthesia were enrolled. They were randomly allocated to receive oral clonidine (0.2 mg) or placebo as premedication 90-120 min before surgery. All the patients received Succinylcholine (1.5 mg kg(-1)) after induction of anesthesia with Fentanyl (50 microg) and Thiopentone (5 mg kg(-1)). The anesthesia was maintained with halothane (1.5 Mac) in 50% mixture of N2O/O2. Heart rate and systolic blood pressure were recorded before, immediately after and then every 5 min after intubation until 20 min. The Clonidine group showed a significant superiority over placebo in the prevention of increase in systolic blood pressure as well as heart rate over the intubation. A significant difference was observed in both heart rate and systolic blood pressures were significantly higher in Control group at three subsequent measurements following intubation. The results of this study suggest that orally administered clonidine in preanesthetic period, provides more haemodynamic stability and attenuates the stress response to laryngoscopy and intubation.

Effects of combination of intrathecal lidocaine and two doses of intrathecal midazolam on post-operative pain in patients undergoing herniorrhaphy: a randomized controlled trial.

Assessment of the effect of combination of intrathecal midazolam and lidocaine on postoperative pain was the aim of this study. This randomized controlled trial was performed during 2007 in a teaching hospital of Arak University of Medical Sciences. Forty five male patients who were candidates for elective inguinal herniorrhaphy entered the study and randomly divided into three groups of control (lidocaine 5% plus normal saline), M 0.5 (lidocaine 5% and midazolam 0.5 mg) and M 1.0 (lidocaine 5% and midazolam 1 mg) according intrathecal solution injected for spinal anesthesia. Mean arterial blood pressure, heart rate, post-operative pain, narcotic requirements and complications (nausea, vomiting, pruritic, headache, hypotension and bradycardia) were recorded. The severity of post-operative pain was lowest in M 1.0 group in all postoperative measurements except at 2 h after operation. With regard of complications, only there was significant difference in vomiting between three groups which had the highest frequency in M 0.5 group. No severe hypotension was seen; though, bradycardia occurred in one patient in M 0.5 group which needed treatment. Present findings suggest that administration of intrathecal midazolam (especially 1 mg) together with lidocaine is effective in reducing post-operative pain in patients undergoing open inguinal herniorrhaphy and is not associated with adverse effect.

Effect of adding ketamine to pethidine on postoperative pain in patients undergoing major abdominal operations: a double blind randomized controlled trial.

To determine the effect of adding ketamine to pethidine in reducing post-operative pain in patients undergoing major abdominal operations, in a double blind randomized controlled trial, 100 patients aged 15-60 years who were candidate for elective major abdominal surgery allocated into two groups of pethidine + ketamine group (5 mg pethidine and 0.25 mg kg(-1) ketamine) or pethidine and placebo group (10 mg pethidine and NS) according to the regimen prescribed in postanesthesia care unit. Severity of pain (using visual analogue scale), prescribed dose of pethidine and side effects were recorded until 24 h after operation. Regarding post-operative pain, pethidine + ketamine group showed significant lower scores in all the times except 0 min, 2, 6 and 16 h. Nausea was significantly less frequent amongst pethidine + placebo group at times of 0, 15, 30 and 45 min (p < 0.05). Comparison of two groups did not show significant differences in prescribed pethedine dose in 0, 9, 12, 16, 20 and 24 h (p > 0.05). Yet, the mean dose of administered pethidine as rescue analgesic was significant lower in pethidine + ketamine group compared to pethidine + placebo group (112 +/- 31.5 mg vs. 133.5 +/- 24.5 mg, p < 0.001). In conclusion, our results showed that co-administration of ketamine and pethidine in postanesthesia care unit will improve postoperative pain and reduce narcotic consumption. It may, however, increase rate of postoperative nausea in the first hour after operation.

Entonox for labor pain: a randomized placebo controlled trial.

This study aims to investigate the effectiveness of nitrous oxide on pain of labor contractions and on maternal SaO2. The patients were randomized to receive either a pre-prepared mixture of 50% nitrous oxide and oxygen or 50% oxygen by a coin. Study drugs started as early as the onset of pain with each contraction. The patient herself administered gases via a facemask connected to the uni-directional valve which enables the patients to breathe fresh gas in each inspiration. The gas administration was continued to the end of contraction pain at which the patient breathed the room air. Variables such as SaO2, blood pressure, pain and side effects were recorded. 534 ASA I and II parturients, aged from 16 to 35 years, scheduled for elective labor from September 2004 to 2006 were evaluated. Four patients were lost from the study. The mean age of patients was 25.5+/-4.3 years. During the first three measurements, the SaO2 was significantly higher in control group. In addition, the mean arterial pressure was comparable between groups except two first measurements in which the control group was higher. All the Visual Analogue Scale (VAS) values were significantly lower in nitrous oxide group. There were no significant differences in 1st and 5th min apgar scores between groups. All of the side effects were significantly higher among patients in nitrous oxide. In conclusion, our data indicate that using nitrous oxide 50% provides significant pain relief. Nonetheless, it is associated with few side effects, nitrous oxide can be quickly implemented during advanced painful labor.

Comparison of simultaneous administration of lithium with L-NAME or L-arginine on morphine withdrawal syndrome in mice.

Due to the claim that chronic administration of lithium or L-N(G)-nitroarginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor reduces morphine withdrawal syndrome, the effects of chronic administration of lithium, L-NAME, or L-arginine (L-Arg), a precursor of NO, alone or co-administration of lithium with L-Arg or L-NAME, on naloxone-precipitated withdrawal syndrome and physical dependence development to morphine in mice chronically treated with morphine, were evaluated. Morphine dependency was induced by the intraperitoneal injection (i.p.) of morphine (10 mg/kg), once daily for 7 days. Physical dependence to morphine was observed by precipitating an abstinence syndrome with naloxone (2 mg/kg, i.p.). Chronic administration of L-NAME (10 mg/kg, i.p., once daily, for 7 days after 10 days of receiving only tap water and food prior to naloxone), decreased all withdrawal signs significantly, while L-Arg (200 mg/kg, as above) increased only some withdrawal signs significantly in morphine-dependent mice. Chronic administration of lithium (600 mg/kg, in drinking water) alone or co-administration of lithium (as above) with L-NAME (10 mg/kg) or L-Arg (200 mg/kg, i.p., once daily) for 7 days after 10 days of receiving only lithium (as above) and food, decreased all withdrawal signs and physical dependence significantly in morphine-dependent mice. The results obtained indicate that co-administration of L-NAME with lithium increases the effect of lithium or L-NAME alone, on withdrawal signs, but this increase is not significantly different as compared to chronic lithium or L-NAME administration alone; while co-administration of L-Arg with lithium decreases the effects of lithium on withdrawal signs and this decrease is not significant as compared to chronic lithium administration alone. These findings indicate that nitric oxide may be involved in modulation of naloxone-induced withdrawal syndrome, and treatment with lithium could have some effect on this system. Copyright 2000 John Wiley & Sons, Ltd.