Lidocaine serum concentration after epidural administration in combination with morphine and fentanyl in rabbit--a preliminary study.

Morphine and fentanyl are often used as adjuvants in epidural anesthesia to prolong analgesia. The aim of this study was to evaluate the impact of addition of morphine or fentanyl to lidocaine on serum lidocaine concentrations in rabbits after epidural administration. During general anesthesia, rabbits of the group L received epidurally 2% lidocaine, rabbits of the group LM 2% lidocaine and morphine, and rabbits of the group LF 2% lidocaine and fentanyl. Blood for determination of serum lidocaine concentration was taken before anesthesia and in first 90 min after epidural administration. After 5, 10, and 25 min in the group L the lidocaine serum concentrations were the lowest, while in the group LM the lidocaine serum concentrations were the highest. Morphine and fentanyl did not cause significant changes of serum lidocaine concentration in rabbits and may be used as adjuvant in epidural anesthesia without significant increase in lidocaine absorption from epidural space.

Ischemic preconditioning decreases laparoscopy induced oxidative stress in the liver.

Experimental studies indicate that oxidative stress during and after laparoscopic surgery may cause liver ischemia-reperfusion injury. The aim of the study was to assess the effect of ischemic preconditioning against liver damage during pneumoperitoneum on oxidative stress. Twenty one New Zealand rabbits were divided into three groups of seven animals. Control group (C) rabbits received anesthesia for 60 min alone; 15 mm Hg intra-abdominal pressure with CO2 for 60 min was used in the pneumoperitoneum group animals (PNP); and 15-min insufflation and 10-min desuflation followed by 60-min pneumoperitoneum were used in the ischemic preconditioning group animals (IP). Venous blood samples were obtained at different time points to measure lipid hydroperoxide, glutathione reductase and total antioxidant status as indicators of increased oxidative stress. Aspartate transaminase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were evaluated as indicators of hepatocellular injury. The Kruskal-Wallis and Mann-Whitney U tests were used on statistical analysis. Elevated intra-abdominal pressure was found to produce significant increase in lipid hydroperoxide at the end of pneumoperitoneum and 30 min after desuflation in comparison with pre-insufflation period, and with both C and IP groups at the same time points. Total antioxidant status level decreased significantly in the PNP group at 24 h of desuflation. At 24h of desuflation, the AST, ALT and LDH levels were significantly increased in the PNP group in comparison with the levels measured before induction of anesthesia, and with the C and IP groups. Study results demonstrated that ischemic preconditioning prevented hepatocyte injury and oxidative stress during CO2 pneumoperitoneum.

Comparison of the effects of low intra-abdominal pressure and pentoxifylline on oxidative stress during CO2 pneumoperitoneum in rabbits.

BACKGROUND: The aim of this study was to investigate the effect of low-pressure pneumoperitoneum and pentoxifylline, a methylxanthine derivative, in the prevention of injury caused by free oxygen radicals generated during CO(2 )pneumoperitoneum. METHODS: Twenty-eight rabbits were allocated randomly to 4 groups. Control group rabbits (group 1) were subjected to anesthesia for 60 min; group 2 and 3 animals were subjected to a CO(2) pneumoperitoneum (15 or 7 mm Hg); and group 4 rabbits received 50 mg/kg pentoxifylline, followed by a 15-mm-Hg pneumoperitoneum. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), lipid hydroperoxide, glutathione reductase and total antioxidant status were measured. RESULTS: Compared with group 1, a significant increase in lipid hydroperoxide levels at the end of the pneumoperitoneum and 30 min after deflation and a significant decrease in total antioxidant status 24 h after deflation were recorded in group 2. In addition, a significant increase was observed in ALT, AST and LDH levels. These changes were attenuated by low-pressure pneumoperitoneum, whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. CONCLUSION: Low-pressure pneumoperitoneum could attenuate ischemia/reperfusion injury induced by CO(2 )pneumoperitoneum in a rabbit model whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. Pentoxifylline did not prevent the development of oxidative stress.

Comparison of dexamethasone, metoclopramide, and their combination in the prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy.

BACKGROUND: Postoperative nausea and vomiting (PONV) are one of the most common complaints following anesthesia and surgery. This study was designed to evaluate the efficacy of dexamethasone, metoclopramide, and their combination to prevent PONV in patients undergoing laparoscopic cholecystectomy. METHODS: A total of 160 ASA physical status I and II patients were included in this randomized, double blind, placebo-controlled study. Patients were randomly assigned to 4 groups (n = 40 each): group 1 consisting of control patients administered 0.9% NaCl; group 2 patients received metoclopramide 10 mg just before the end of anesthesia; group 3 patients received dexamethasone 8 mg after the induction of anesthesia; and group 4 patients received dexamethasone 8 mg after the induction of anesthesia and metoclopramide 10 mg before the end of anesthesia. The incidence of PONV, mean visual analog pain scores at rest and on movement, time to the first request for analgesia, side effects, and well-being score were recorded during the first 24 h postoperatively. RESULTS: Data were analyzed using one-way analysis of variance (ANOVA) and the chi2 test, with p < 0.05 considered statistically significant. The total incidence of PONV was 60% with placebo, 45% with metoclopramide, 23% with dexamethasone, and 13% with the combination of dexamethasone plus metoclopramide. None of the dexamethasone plus metoclopramide group patients (p < 0.05 versus groups 1 and 2) and one dexamethasone group patient (p < 0.05 versus group 1) required antiemetic rescue, as compared with four patients in the metoclopramide group and six patients in the placebo group. Pain scores, the time to the first request for analgesia, and side effects were similar across the study groups. CONCLUSIONS: Dexamethasone and the combination of dexamethasone plus metoclopramide were more effective in preventing PONV than metoclopramide and placebo.

Aminotransferases after experimental pneumoperitoneum in dogs.

BACKGROUND: Laparoscopic surgery has rapidly become a popular and widely used technique. Elevated intra abdominal pressure due to gas insufflation for laparoscopic surgery may result in a number of local and systemic effects on the organism. The effects of pneumoperitoneum on the cardiovascular and respiratory system are well known today, but very few studies have been carried out on the consequences of pneumoperitoneum on hepatic integrity. The aim of the present study was to assess changes in aminotransferases, bilirubin and prothrombin time after pneumoperitoneum in dogs. METHODS: The effects of different levels and duration of intra abdominal pressure and different gases on liver function test were investigated in dogs. The levels of aspartate aminotransferase, alanine aminotransferase, total and direct bilirubin, and prothrombin time, according to the duration and the level of pneumoperitoneum and gas, were measured at 6, 12, 24 and 48 h of desufflation. RESULTS: The levels of total bilirubin, direct bilirubin and prothrombin time showed no significant alteration. A statistically significant (P < 0.01) elevation of aspartate aminotransferase and alanine aminotransferase was recorded in the group of animals with higher intra abdominal pressure and longer duration of pneumoperitoneum. They returned to normal values within 48 h. CONCLUSION: Transient elevation of hepatic transaminases occurred after laparoscopic surgery, but they returned to normal values within 48 h. These increases were more prominent with higher and longer intra abdominal pressures irrespective of the type of insufflated gas. Alteration in aminotransferases was not associated with any clinical signs of hepatic dysfunction in experimental animals.