Acid-base balance during laparoscopy. The effects of intraperitoneal insufflation of carbon dioxide and nitrous oxide on acid-base balance during controlled ventilation.

Laparoscopy may have significant effects on homeostasis, particularly on the cardiovascular and pulmonary systems. The surgeon needs to appreciate the complex interactions of increased intra-abdominal pressure, changes in patient position, and gas absorption in order to appropriately select patients for laparoscopic procedures. Practical guidelines for the avoidance and management of complications due to pathophysiologic derangement during laparoscopy are included.

Background: Endoscopic surgical procedure has recently been applied to not only intraabdominal or intrathoracic surgery but also saphenous vein harvesting, because it is less invasive and more cosmetically advantageous. Carbon dioxide insufflation during an endoscopic saphenous vein harvesting may cause an adverse effects on arterial blood gas and hemodynamic variables. This study was conducted to evaluate the safety of carbon dioxide insufflation during endoscopic saphenous vein harvesting. Methods: Patients in ASA physical status III or IV, scheduled for an endoscopic saphenous vein harvesting (n=30) were gathered for the evaluation. Until the end of the procedure, controlled mechanical ventilation (tidal volume: 10 ml/kg, respiratory rate: 10 rates/min) and ventilator mode was fixed in this tidal volume and respiratory rate. Arterial blood gas analysis, end-tidal carbon dioxide, blood pressure and heart rate were measured before and at 10, 20, 30, 40 minutes after carbon dioxide insufflation. Results: Preinsufflation values of PaCO2 (partial pressure of arterial carbon dioxide) and PETCO2 (partial pressure of end-tidal carbon dioxide) were 33.4 ± 3.6 mmHg and 24.1 ± 4.1 mmHg, respectively. PaCO2 was significantly increased at 30 and 40 minutes after carbon dioxide insufflation (40.1 ± 7.4 mmHg and 41.4 ± 8.6 mmHg). PETCO2 was significantly increased at 20, 30 and 40 minutes after carbon dioxide insufflation(27.6 ± 5.5 mmHg, 28.9 ± 7.0 mmHg and 29.6 ± 7.8 mmHg). But, the magnitude of difference between PaCO2 and PETCO2 was not significantly different. Conclusions: During endoscopic saphenous vein harvesting, PaCO2 was significantly increased compared with preinsufflation values. Careful monitoring of PaCO2 is mandatory during the procedure.

Hemodynamic measurements were performed in 10 healthy women undergoing elective laparoscopy for the investigation of infertility. A standardized anesthetic technique which included the application of positive end-expiratory pressure (PEEP), 0.49 kPa (3.7 mmHg) was utilized. The following variables were studied: cardiac output, stroke volume and left ventricular ejection time (determined non-invasively with impedance cardiography), heart rate, blood pressure, total peripheral vascular resistance and end-tidal carbon dioxide (ET-CO2). The combination of 25 degrees head-down tilt and PEEP ventilation during laparoscopy was associated with a pressure response that restored arterial pressures to essentially pre-anesthetic levels. Net cardiac effects were small. With this regime low pressure 0.7-1.1 kPa (5-8 mmHg) intra-abdominal insufflation with CO2 was associated with only minor cardiovascular changes. There were no indications that 0.49 kPa PEEP during laparoscopy produced adverse cardiovascular effects. The application of PEEP reduced (P less than 0.001) ET-CO2. There was no net increase in ET-CO2 after CO2-insufflation compared to the measurement after induction of anesthesia. This is in contrast to earlier studies without PEEP where a significant net increase in ET-CO2 was reported after CO2-insufflation.

Background: Previous studies have shown that the ProSeal laryngeal mask airway (PLMA) forms a more effective seal than the classic laryngeal mask airway (LMA) during a static oropharyngeal leak test and isolates the respiratory tract from the gastrointestinal tract when correctly positioned, but there is no evidence that it is a better ventilatory device. In the present study, we tested the hypothesis that the PLMA is a more effective ventilatory device than either the LMA or the endotracheal tube (ETT) in healthy anesthetized females undergoing gynecologic laparoscopic surgery at 120 ml/kg minute ventilation volume with the cuff fully inflated. Methods: We studied 34 female patients (ASA physical status I, 22－46 yr) undergoing gynecologic laparoscopic surgery. Patients were randomized into three groups according to ventilatory devices;Group 1 (ETT, n = 11), Group 2 (LMA, n = 12) and Group 3 (PLMA, n = 11). After induction of anesthesia, patients were ventilated in the same mode in each group. We measured peak inspiratory pressure (PIP), , , and arterial end-tidal Pdifference () at 10 min after induction of anesthesia (stage 1), 10 min after insufflation (stage 2), 10 min after Trendelenburg (T) position (stage 3) and 30 min after T position (stage 4). Results: There were no significant differences among the three groups in , , and PIP. , and PIP increased significantly at stages 2 through 4 compared to stage 1 (P ＜ 0.05). decreased significantly at stage 4 compared to stage 1 (P ＜ 0.05). was maintained within normal range from stage 1 to stage 4. Conclusions: This study demonstrates that pulmonary gas exchange is not affected by the choice of ventilatory devices during gynecologic laparoscopic surgery in young female patients under a Trendelenburg position and pneumoperitoneum.

Biliary diseases known since ages constitute major portion of digestive tract disorders world over. Among these cholelithiasis being the fore runner causing general ill health, thereby requiring surgical intervention for total cure. The study was undertaken in an attempt to compare the hemodynamic changes in patient undergoing laparoscopic cholecystectomy using different intra-abdominal pressures created due to carbon dioxide insufflation. The patients were randomly allocated to one of the three groups in which different levels of intra-abdominal pressures (8-10mmHg,11-13mmHg and 14mmHg and above) were maintained. The base line parameters monitored were heart rate, non invasive blood pressur(systolic and mean)and end tidal carbon dioxide. All the parameters were monitored at various intervals i.e. Immediately during insufflation, 5min, 10min, 20min, 30min after CO2 insufflation and after every 10min if surgery exceeds 30min, at exsufflation,10min after CO2 exsufflation. Patients were ventilated with Pedius Drager Ventilator keeping tidal volume 8-10ml/kg and respiratory rate 12-14 breaths/min. During surgery patients were placed in reverse Trendlenburg position (head up) at 15°. The results obtained were evaluated statistically and analyzed. Baseline characteristics were found to be comparable. Hemodynamic variables were reported as mean and standard deviation. Statistical significance among groups was evaluated using Analysis of Variance and unpaired student t test (two tailed). Inter-group comparisons were made using Bonferroni test. A p-value of <0.05 was considered as statistically significant. In all the three groups the mean heart rate (baseline 84.08 ± 12.50, 87.96 ± 15.73 and 86.92 ± 17.00 respectively) increased during CO2 insufflation and the rise in heart rate continued till exsufflation after which it decreased and at 10min after exsufflation the heart rates were comparable with the baseline. The inter-group comparison of mean heart rate between I & III was statistically significant at 10, 20, 30min after CO2 insufflation which continued at exsufflation and 10min after CO2 exsufflation [p < 0.05]. The inter-group comparison between I & III showed statistically significant difference in systolic blood pressure at 10, 20, 30min after CO2 insufflation, at exsufflation and 10min after exsufflation [p = 0.0001] and mean arterial pressure at 5, 10, 20, 30min after CO2 insufflation, at exsufflation and 10min after exsufflation [p = 0.0001]. Comparison between Group I and Group III & between Group II and Group III showed highly significant statistical difference in EtCO2 immediately after insufflation and the same trend was seen till the completion of surgery and even 10min after exsufflation [p = 0.001]. The conclusion drawn from the study was that laparoscopic cholecystectomy induces significant hemodynamic changes intraoperatively, the majority of pathophysiological changes are related to cardiovascular system and are caused by CO2 insufflation .A high intra-abdominal pressure due to CO2 insufflation is associated with more fluctuations in hemodynamic parameters and increased peritoneal absorption of CO2 as compared to low intraabdominal pressure so low pressure pneumoperitoneum is feasible for laparoscopic cholecystectomy and minimizes the adverse hemodynamic effects of CO2 insufflation.

Carbon dioxide (CO2) insufflation is expected to be safe and effective in endoscopic submucosal dissection (ESD) as well as in other endoscopic procedures. The present study aimed to clarify the usefulness and safety of CO2 insufflation in gastric ESD. A total of 102 consecutive patients were randomly assigned to CO2 insufflation (CO2 group, n = 54) or air insufflation (Air group, n = 48). Abdominal pain and distension were chronologically recorded on a 100-mm visual analog scale (VAS). The volume of residual gas in the digestive tract was measured by computed tomography performed immediately after ESD. Abdominal pain on a 100-mm VAS in the CO2 vs. Air group was 4 vs. 3 immediately after ESD, 4 vs. 4 one hour after the procedure, 3 vs. 3 three hours after the procedure, and 1 vs. 4 the next morning, showing no difference between the groups. In addition, there was no difference in abdominal distension on the 100-mm VAS over the time course of the study. The volume of residual gas in the digestive tract in the CO2 group was significantly smaller than that in the Air group (643 mL vs. 1037 mL, P < 0.001). The dose of sedative drugs did not differ between the groups. Neither the incidences of complications nor clinical courses differed between the groups. Compared with air insufflation, CO2 insufflation during gastric ESD significantly reduced the volume of residual gas in the digestive tract but not the VAS score of abdominal pain and distension.

Literatur

Carbon dioxide is the most widely used gas to establish pneumoperitoneum during laparoscopic surgery. Gastrointestinal trauma may occur during the peritoneal insufflation or during the operative phase itself. Early diagnosis of these injuries is critical. To assess changes in end-tidal carbon dioxide (ETCO2) following gastric perforation during pneumoperitoneum in the rat. Wistar rats were anesthetized, tracheotomized and mechanically ventilated with fixed minute volume. Each animal underwent a 1 cm abdominal longitudinal incision. A 0.3 x 0.3 cm cross-incision of the stomach was performed in the perforation group but not in the controls (n = 10/group) and the abdomen was closed in both groups. After stabilization, CO2-induced pneumoperitoneum was established at 0, 5, 8 and 12 mmHg for 20 min periods consecutively, each followed by complete pressure relief for 5 min. Ventilatory pressure increased in both groups when pneumoperitoneal pressure 5 mmHg was applied, but more so in the perforated stomach group (P = 0.003). ETCO2 increased in both groups during the experiment, but less so in the perforated group (P = 0.04). It then returned to near baseline values during pressure annulation in all perforated animals but only following the 0 and 5 mmHg periods in the controls. When subjected to pneumoperitoneum, ETCO2 was lower in rats with a perforated stomach than in those with an intact stomach. An abrupt decrease in ETCO2 during laparoscopy may signal gastric perforation.

Laparoscopic cholecystectomy (LSC) is being performed increasingly often. The carbon dioxide cavity increases end-expiratory carbon dioxide (exCO2), which can be regulated by mechanical ventilation. Because about 20-40% carbon dioxide remains in the patient at the end of surgery, we were interested in its influence on spontaneous respiration. PATIENTS AND METHODS. Fifteen patients classed as ASA 1-2 and undergoing LSC were compared with 15 patients (also ASA 1-2) undergoing laparotomy for cholecystectomy (LAP). All patients had balanced anaesthesia with fentanyl, enflurane, nitrous oxide and vecuronium. After surgery they were extubated when spontaneous respiration and vigilance were adequate. In the next 3 h we continuously determined exCO2 in the expired air through an intranasal catheter, and oxygen saturation (SAT), respiratory rate (RR) and heart rate (HR) using Oscar (Datex) and Ohmeda (Braun) apparatus while the patients were breathing room air. The blood pressure (BP) was determined intermittently. Postoperative pain treatment was standardized. RESULTS. The groups were reduced comparable with respect of the anthropometric data, because the weight was significantly higher in the LAP group. Fentanyl consumption was also significantly higher in the LAP group, reflecting the more pronounced trauma than with LSC. Mean exCO2 was 46 mmHg after LSC and 36 mmHg after LAP (P less than or equal to 0.05), continuously decreasing in the LSC group and increasing in the LAP group to 40 mmHg after 3 h. Mean RR was 18-20.min-1 after LSC and 12-15.min-1 after LAP during this period (P less than or equal to 0.05). There were no differences in SAT (94-96%), HR (75.min-1) and BP (130/80 mmHg). DISCUSSION AND CONCLUSIONS. The remaining carbon dioxide after LSC has important implications for postoperative spontaneous respiration. Probably due to an activation of carbon dioxide receptors, RR is increased to eliminate residual carbon dioxide. This is confirmed by a significantly increased exCO2 compared with that in the LAP group. This effect lasts at least 3 h, exCO2 being comparable in both groups, but RR is still increased after LSC. This different respiratory pattern does not affect SAT, being normal without hypoxic episodes. Cardiovascular parameters were also normal without group differences. We conclude that the carbon dioxide peritoneal cavity has important consequences for postoperative ventilation. Using our anaesthetic technique and postoperative treatment exCO2 reaches normal values after about 3 h due to an increased RR. If other methods, e.g., stronger opioids, which decrease carbon dioxide response are used, this effect may even be prolonged and more pronounced. We are now performing an investigation to evaluate this effect.

不妊症患者11名について, 体外受精のための卵胞吸引術を硬膜外麻酔下で行い呼吸循環系の変動を調べた. Trendelenburg (T) 体位時間 (以下いずれも平均値) 36.4分, 腹腔内圧13mmHg, 傾斜角度27.6度であった. 気腹施行後呼吸数は22.4回と増加, PaCO2は30.8mmHgと低下した. T体位にした後は, 呼吸数が24.7回に増加, PaCO2も39.9mmHgと上昇したが, 患者自身の努力により代償が可能な範囲内であった. 心拍数は有意に低下したが平均血圧は一定に保たれた. 症例の70%が手術中の息苦しさや不安感を訴え, 54%が次回の手術には他の麻酔法を望んだ. 全身麻酔併用等の工夫が必要であるとともに, 卵子段階への薬剤の影響も今後検討されるべき課題である.