Comparison of the Effects of Low Intra-Abdominal Pressure and Pentoxifylline on Oxidative Stress during CO2 Pneumoperitoneum in Rabbits (original) (raw)
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Surgical Endoscopy, 2008
Background: Disturbed liver function tests are associated with the pneumoperitoneum applied for biliary and non-biliary laparoscopic surgical procedures. The extent, duration and reversibility of such an injury are unknown. An isolated organ model was used to assess reversibility of liver injury in a CO 2 -pneumoperitoneum-like environment. Methods: Rat livers (n = 63) were isolated and perfused within a chamber pressurized at 0, 3, 5, 8, 12, 15 or 18 mmHg for 60 minutes. Pressure was annulled during the ensuing 61-90 minutes in one-half of the groups and markers of liver function were measured and recorded. Results: Inflow pressure level, flow rate, effluent partial O 2 and CO 2 pressures, O 2 extraction rate, lactate dehydrogenase level, lactic to pyruvic acid ratio, and total xanthine oxidase and dehydrogenase levels became abnormal, starting at 15 minutes after a pressure >5 mmHg was applied in the chamber. Signs of injury slowly reversed towards baseline values in all groups except for the 15 mmHg and 18 mmHg-pressurized ones, even after pressure had been annulled for 30 minutes. Conclusions: CO 2 -pneumoperitoneum-like conditions directly injured rat liver tissue to a degree which correlated with the amount of applied pressure. Damage caused by pressure ‡15 mmHg was no longer reversible if it had been applied over a 60-minute period.
Pathogenesis CO 2 Pneumoperitoneum-Induced Metabolic Hypoxemia in a Rabbit Model
Journal of The American Association of Gynecologic Laparoscopists, 2002
To investigate the effects of carbon dioxide (CO2) pneumoperitoneum-induced changes in blood gases, acid-base balance, and oxygen homeostasis in rabbits.Prospective, randomized, controlled study (Canadian Task Force classification I).University training and teaching center.Twenty-six adult female New Zealand white rabbits.Anesthesia and pneumoperitoneum.In anesthetized rabbits arterial blood gases, acid-base balance, oxygenation values, and lactate concentrations were assayed during 2 hours. Spontaneous breathing, superficial and optimal ventilation without pneumoperitoneum, and with pneumoperitoneum at low (6 mm Hg) and higher (10 mm Hg) insufflation pressures were compared. The CO2 pneumoperitoneum profoundly affected blood gases, acid-base balance, and oxygen homeostasis. Carboxemia with increasing end-tidal CO2 and partial pressure of CO2 (p< 0.001), acidosis with decreasing pH (p< 0.001), and base deficiency with decreasing actual base excess (p< 0.001), standard base excess and standard bicarbonate and acid excess with increasing hydrogen bicarbonate (p<0.05 and <0.01) were found. Desaturation (p <0.01) with decreasing oxyhemoglobin p <0.05) and hemoglobin oxygen affinity (p <0.01) were also found. Carboxemia with acidosis was more pronounced with higher (p <0.01) than with lower (p >0.05) intraperitoneal pressures, and also with spontaneous breathing (p <0.05) and superficial ventilation (p< 0.001) than with optimal ventilation, resulting in metabolic hypoxemia.In superficially ventilated and spontaneously breathing rabbits, CO2 pneumoperitoneum profoundly affected blood gases, acid-base balance, and oxygen homeostasis, resulting in metabolic hypoxemia. With optimal ventilation and low intraperitoneal pressure carboxemia, respiratory acidosis, and changes in oxygen metabolism were minimal.
BACKGROUND: CO 2 -pneumoperitoneum used in endoscopic surgery induces system effects by CO 2 absorption. This study investigated the effect of the addition of O 2 to CO 2 -pneumoperitoneum, upon CO 2 absorption. METHODS: The effect of a pneumoperitoneum using 100% CO 2 or 94% CO 2 ⍣ 6% O 2 upon arterial blood gases, acid base and O 2 homeostasis was evaluated. In series A suboptimal ventilation and a pneumoperitoneum pressure (PP) of 10 mmHg was used. In series B adequate ventilation and PP of 6 mmHg was used. RESULTS: CO 2pneumoperitoneum profoundly affected blood gases and acid base homeostasis i.e. increasing pCO 2 , HCO 3 (P < 0.001) and lactate concentrations (P < 0.05) and decreasing pH, actual base excess and standard bicarbonate (P < 0.001), resulting in metabolic hypoxaemia with desaturation, lower pO 2 (P < 0.001) and O 2 Hb (P < 0.05). These effects were more pronounced with higher PP and suboptimal ventilation. CONCLUSION: CO 2pneumoperitoneum profoundly affected blood gases and acid base homeostasis resulting in metabolic hypoxaemia. The addition of 6% of O 2 to the CO 2 -pneumoperitoneum prevented these effects to a large extent. If these preliminary data are confirmed in the human, the addition of a few percent of O 2 to CO 2 could become important for endoscopic surgery of long duration, especially in obese patients with limited cardiorespiratory adaptation and steep Trendelenburg.
Does Prolonged Pneumoperitoneum Affect Oxidative Stress Compared with Open Surgical Procedures?
Journal of Endourology, 2005
Background and Purpose: As laparoscopic surgery has evolved, it has become part of the urologic surgical armamentarium and is now used to perform more complex procedures. Carbon dioxide, used to create pneumoperitoneum, produces physiologic changes in various organs, including the kidneys. Such changes are associated with altered redox status because of the release of free radicals and changes in oxidative stress signals. It is unknown whether prolonged pneumoperitoneum is associated with an increase in oxidative stress compared with open surgery. The objective of this study was to compare oxidative stress in patients undergoing urologic laparoscopic and open operations. Patients and Methods: Urine samples were obtained immediately preoperatively, immediately postoperatively, and at 6 and 18 hours after surgery from 10 patients who underwent urologic laparoscopic surgery and 10 patients who underwent open surgery. Concentrations of the oxidative stress marker isoprostane (8iso-prostaglandin F 2a) were measured, and the results were analyzed with respect to clinical factors associated with the type of surgery. Results: Urinary isoprostane concentrations (mean ؎ SEM) in the laparoscopic and open groups showed an increase immediately after surgery to 189.0 ؎ 64.2% and 141.1 ؎ 45.8% of the preoperative values, respectively. A decrease in isoprostane was subsequently observed in both groups at 6 hours postoperatively, with preoperative values restored at 18 hours postoperatively (126.3 ؎ 19.7% and 89.5 ؎ 55.9% at 6 and 18 hours, respectively, in the laparoscopic group and 130.7 ؎ 41.6% and 88.7 ؎ 20.4% at 6 and 18 hours, respectively, in the open-surgery group). Although in both groups the peak PGF 2a concentration was observed immediately (0 hours) postoperatively, no significant differences were observed between the groups at 0, 6, and 18 hours. In the laparoscopic-surgery group, the mean increase tended to be higher and the decrease to be less prolonged than in the open-surgery group. Conclusion: Oxidative stress, as measured by urinary 8-iso-prostaglandin F2a, is produced by both laparoscopic and open urologic surgery. The findings of our nonrandomized study suggest a pattern of increased oxidative stress postoperatively with either type of surgery, with subsequent return almost to preoperative levels. Prolonged laparoscopic operative time did not affect oxidative stress levels.
The Effect of Dexmedetomidine on Oxidative Stress during Pneumoperitoneum
BioMed Research International, 2014
Purpose. This study was intended to investigate the effect of dexmedetomidine on oxidative stress response in pneumoperitoneum established in rats.Methods. Animals were randomized into three groups, group S: with no pneumoperitoneum, group P: with pneumoperitoneum established, and group D: given 100 mcg intraperitoneal dexmedetomidine 30 min before establishment of pneumoperitoneum. Plasma total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) activity were measured 30 min after conclusion of pneumoperitoneum.Results. The mean TOS level was significantly higher in group P than in the other two groups, and the TOS level was significantly higher in group D than in group S (P<0.05). Plasma TAS level was found to be lower in group P than in the other two groups, and the TAS level was lower in group D than in group S (P<0.05). Consequently, the OSI was significantly higher in group P than in groups D and S (P<0.05).Conclusions. Ischemia-repe...