Helium vs carbon dioxide gas Insufflation with or without saline lavage during laparoscopy

BACKGROUND: Helium is an inert gas that, if used for insufflation during laparoscopy, may be followed by less postoperative pain than carbon dioxide (CO2) insufflation, due to a more limited effect on intraabdominal pH and metabolism. Saline lavage has also recently been shown to reduce postoperative pain following laparoscopic surgery. To evaluate these possibilities and to better define the clinical safety of helium insufflation, we undertook a prospective randomized trial comparing CO2 and helium insufflation with or without saline lavage in patients undergoing elective laparoscopic upper abdominal surgery. METHODS: From January to November 2000, 173 patients undergoing elective laparoscopic cholecystectomy or fundoplication were randomized to undergo laparoscopy with either CO2 or helium insufflation. Within each group, patients were further randomized to undergo peritoneal lavage with 2 L of 0.9% saline at the end of the surgical procedure. This yielded the following four patient groups; CO2 (group 1, n = 47), CO2 + saline lavage (group 2, n = 43), helium (group 3, n = 43) and helium + saline lavage (group 4, n = 40). Patients were blinded to their randomization, and post-operative assessment was also performed by a blinded investigator, who applied a standardized scoring system to assess postoperative pain. RESULTS: The study groups were well matched for age, sex, weight, American Society of Anesthesiologists (ASA) status, duration of surgery, and volume of gas utilized, and 81% of patients were discharged within 48 h. There were no differences in the incidence of postoperative complications among the study groups, and postoperative pain scores were not significantly different when all four groups were compared. When helium (groups 3 and 4) was compared with CO2 (groups 1 and 2), no differences in pain score were seen. When no lavage (groups 1 and 3) was compared with lavage (groups 2 and 4), less pain was found in the group undergoing saline peritoneal lavage (mean 4-h pain score, 5.9 vs 5.2; 24-h pain score, 4.8 vs 4.1; p > 0.05). CONCLUSIONS: The use of helium insufflation for laparoscopic surgery, while not associated with any significant adverse sequelae, was not associated with less postoperative pain in this trial. The use of saline peritoneal lavage was associated with less pain in the early postoperative period.     

The influence of CO2 versus helium insufflation or the abdominal wall lifting technique on the systemic immune response

BACKGROUND: Both laparoscopic and conventional surgery result in activation of the systemic immune response; however, the influence of the laparoscopic approach, using CO2 insufflation, is significantly less. Little is known about the influence of alternative methods for performing laparoscopy, such as helium insufflation and the abdominal wall lifting technique (AWLT), and the systemic immune response. METHODS: Thirty-three patients scheduled for elective cholecystectomy were randomly assigned to undergo laparoscopy using either CO2 or helium for abdominal insufflation or laparoscopy using only the AWLT. The postoperative inflammatory response was assessed by measuring the white blood cell count, C-reactive protein (CRP) and interleukin-6 (IL-6). The postoperative immune response was assessed by measuring monocyte HLA-DR expression. RESULTS: CRP levels were significantly higher 1 day after helium insufflation when compared with CO2 insufflation; however, no differences were observed 2 days after surgery. The AWLT resulted in significantly higher levels of CRP both 1 and 2 days after surgery when compared with either CO2 or helium insufflation. A small increase in postoperative IL-6 levels was observed in all groups, but no significant differences were seen between the groups. After both helium insufflation and AWLT a significant decrease in HLA-DR expression was observed, in contrast to the CO2 group. CONCLUSION: Carbon dioxide used for abdominal insufflation seems to limit the postoperative inflammatory response and to preserve parameters reflecting the immune status. These findings may be of importance in determining the preferred method of laparoscopy in oncologic surgery.     

Analysis of the hemodynamic and ventilatory effects of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy uses carbon dioxide, a highly diffusable gas, for insufflation. With extended periods of insufflation, patient arterial carbon dioxide levels may be adversely altered. Patients were selected for laparoscopic cholecystectomy using the same criteria as for open cholecystectomy. Twenty patients (group 1) had normal preoperative cardiopulmonary status (American Society of Anesthesiologists class I), while 10 patients (group 2) had previously diagnosed cardiac or pulmonary disease (class II or III). Demographic, hemodynamic, arterial blood gas, and ventilatory data were collected before peritoneal insufflation and at intervals during surgery. Patients with preoperative cardiopulmonary disease demonstrated significant increases in arterial carbon dioxide levels and decreases in pH during carbon dioxide insufflation compared with patients without underlying disease. Results of concurrent noninvasive methods of assessing changes in partial arterial pressures of carbon dioxide (end-tidal carbon dioxide measured with mass spectrographic techniques) may be misleading and misinterpreted because changes in partial arterial pressures of carbon dioxide are typically much smaller than changes in arterial blood levels and, unlike arterial gas measurements, do not indicate the true level of arterial hypercarbia. During laparoscopic cholecystectomy, patients with chronic cardiopulmonary disease may require careful intraoperative arterial blood gas monitoring of absorbed carbon dioxide.     

Impact of carbon dioxide and helium insufflation on cardiorespiratory function during prolonged pneumoperitoneum in an experimental rat model

BACKGROUND: Experimental studies on laparoscopic surgery are often performed in rats. However, the hemodynamic and respiratory responses related to the pneumoperitoneum have not been studied extensively in rats. Therefore, the aim of this study was to investigate in spontaneously breathing rats the effects of CO2 and helium, insufflation pressure, and duration of pneumoperitoneum on blood pressure, arterial pH, pCO2, pO2, HCO3-, base excess, and respiratory rate. METHODS: Five groups of 9 Brown Norway rats were anesthetized and underwent CO2 insufflation (6 or 12 mmHg), helium insufflation (6 or 12 mmHg), or abdominal wall lifting (gasless control) for 120 min. Blood pressure was monitored by an indwelling carotid artery catheter. Baseline measurements of mean arterial pressure (MAP), respiratory rate, arterial blood pH, pCO2, pO2, HCO3-, and base excess were recorded. Blood gases were analyzed at 5, 30, 60, 90, and 120 min during pneumoperitoneum, and MAP and respiratory rate were recorded at 5 and 15 min and at 15-min intervals thereafter for 2 h. RESULTS: CO2 insufflation (at both 6 and 12 mmHg) caused a significant decrease in blood pH and increase in arterial pCO2. Respiratory compensation was evident since pCO2 returned to preinsufflation levels during CO2 insufflation at 12 mmHg. There was no significant change in blood pH and pCO2 in rats undergoing either helium insufflation or gasless procedures. Neither insufflation pressure nor the type of insufflation gas had a significant effect on MAP over time. CONCLUSION: The cardiorespiratory changes during prolonged pneumoperitoneum in spontaneously breathing rats are similar to those seen in clinical practice. Therefore, studies conducted in this animal model can provide valuable physiological data relevant to the study of laparoscopic surgery.     

Hemodynamic and pulmonary changes during open, carbon dioxide pneumoperitoneum, and abdominal wall-lifting cholecystectomy

Background: Carbon dioxide (CO2) pneumoperitoneum effects are still controversial. The aim of this study was to investigate cardiopulmonary changes in patients subjected to different surgical procedures for cholecystectomy. Methods: In this study, 15 patients were assigned randomly to three groups according to the surgical procedure to be used: open cholecystectomy (OC), CO2 pneumoperitoneum cholecystectomy (PP), and laparoscopic gasless cholecystectomy (abdominal wall lifting [AWL]), respectively. A pulmonary artery catheter was used for hemodynamic monitoring in all patients. A subcutaneous multiplanar device (Laparo Tenser) was used for abdominal wall lifting. To avoid misinterpretation of results, conventional anesthesia was performed with all parameters, and the position of the patients held fixed thoroughout surgery. The following parameters were analyzed: mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), cardiac index (CI), stroke volume index (SVI), central venous pressure (CVP), systemic vascular resistances index (SVRI), mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP), pulmonary vascular resistances index (PVRI), peak inspiratory pressure (PIP), end-tidal CO2 pressure (ETCO)2, CO2 arterial pressure (PaCO2), and arterial pH. Results: All the operations were completed successfully. The Laparo Tenser allowed good exposition of the surgical field. A slight impairment of the cardiopulmonary functions, with reduction of SVRI, MAP, and CI and elevation of pulmonary pressures and vascular resistance, followed induction of anesthesia. However, these effects tended to normalize in the OC and AWL groups over time. In contrast, CO2 insufflation produced a complex hemodynamic and pulmonary syndrome resulting in increased right- and left side filling pressures, significant cardiac index reduction, derangement of the respiratory mechanics, and respiratory acidosis. All of these effects normalized after desufflation. Conclusions: Cardiopulmonary adverse effects of general anesthesia were significant but transitory and normalized during surgery. Carbon dioxide pneumoperitoneum caused a significant impairment in cardiopulmonary functions. In high-risk patients, gasless laparoscopy may be preferred for reliability and absence of cardiopulmonary alterations. apd: 21 December 2000     

Hemodynamic and respiratory effects of pediatric urological retroperitoneal laparoscopic surgery: a prospective study

PURPOSE: Our understanding of the effects of retroperitoneal CO(2) insufflation on cardiopulmonary variables in children remains limited. This study was designed to investigate prospectively the effect of CO(2) insufflation in a pediatric population undergoing retroperitoneal laparoscopic surgery. MATERIALS AND METHODS: We prospectively evaluated a consecutive series of patients enrolled between July 2003 and August 2004. Anesthesia was administered following a standardized protocol. Data collection included respiratory rate, PAP, O(2) saturation, ETCO(2), HR, MAP, electrocardiogram and insufflation pressure. All variables were recorded before, during and after CO(2) insufflation at regular intervals of 1 to 2 minutes, with up to 23 measurements recorded for each period. RESULTS: A total of 18 participants were recruited. Mean +/- SD for age and weight were 79.4 +/- 53.2 months and 26.7 +/- 15.5 kg, respectively. Mean retroperitoneal CO(2) insufflation pressure was kept at 12 mm Hg. Significant differences (p <0.05) in average ETCO(2), PAP and MAP were noted after CO(2) insufflation compared to baseline (pre-pneumoretroperitoneum) values. HR and temperature did not change. At completion of the laparoscopic intervention physiological variables exhibited a trend to return to baseline values. CONCLUSIONS: This prospective study documents significant changes in systemic hemodynamic variables that seem to be directly associated with the insufflation of CO(2) during pediatric retroperitoneal laparoscopic surgery. This ongoing evaluation confirms the effect of laparoscopic urological surgery and CO(2) insufflation on cardiopulmonary function in children.     

Double-blind, prospective, randomized study of warmed, humidified carbon dioxide insufflation vs standard carbon dioxide for patients undergoing laparoscopic cholecystectomy

HYPOTHESIS: Patients undergoing warmed, humidified carbon dioxide (CO2) insufflation for laparoscopic cholecystectomy will (1) maintain a warmer intraoperative core temperature, (2) have their surgeon experience less fogging of the camera lens, and (3) have less postoperative pain than patients undergoing laparoscopic cholecystectomy with standard CO2 insufflation. DESIGN: A double-blind, prospective, randomized study comparing patients undergoing laparoscopic cholecystectomy with standard CO2 insufflation vs those receiving warmed, humidified CO2 (Insuflow Filter Heater Hydrator; Lexion Medical, St Paul, Minn) was performed. Main variables included patient core temperature, postoperative pain, analgesic requirements, and camera lens fogging. RESULTS: One hundred one blinded patients (69 women, 32 men) undergoing laparoscopic cholecystectomy were randomized into 2 groups-52 receiving standard CO2 insufflation (group A) and 49 receiving warmed, humidified CO2 (group B). Mean patient intraoperative core temperature change (group A decreased by 0.03 degrees C, group B increased by 0.29 degrees C, P =.01) and mean abdominal pain (Likert scale, 0-10) at 14 days postoperatively (group A, 1.0; group B, 0.3; P =.02) were different. Other variables (camera lens fogging, early postoperative pain, narcotic requirements, recovery room stay, and return to normal activities) between groups were similar. CONCLUSION: While patients undergoing laparoscopic cholecystectomy with warmed, humidified CO2 had several advantages that were statistically significant, no major clinically relevant differences between groups A and B were evident.     

Videoscopic surgery under local and regional anesthesia with helium abdominal insufflation

Background: High-risk patients may not be good candidates for laparoscopic surgery due to the metabolic consequences of transperitoneal absorption of insufflated CO₂ gas and the necessity of general anesthesia because CO₂ insufflation produces pain. Helium gas is metabolically inert and does not produce pain. Thus it permits an alternative approach to performing laparoscopic surgery in high-risk patients. Methods: Laparoscopic cholecystectomy, appendectomy, hernia repair, and peritoneal dialysis catheter procedures were performed under local or regional anesthesia in high-risk patients utilizing helium gas as the insufflation agent. Results: Twenty-one patients underwent laparoscopic procedures under local or regional anesthesia. None of the procedures initiated under local-regional anesthesia required abandonment of the laparoscopic approach or conversion to general anesthesia. There were no operative or perioperative mortalities. Two incidences of pneumothorax occurred with extraperitoneal hernia repair; one required a tube thoracostomy. Conclusions: Helium gas should be considered the agent of choice for intraperitoneal insufflation in high-risk patients not only because helium avoids the metabolic consequences of CO₂ insufflation but also because it permits selected procedures to be performed under local-regional anesthesia. Helium may be contraindicated for laparoscopic procedures involving extraperitoneal insufflation due to the increased risk for pneumothoraces. Received: 15 April 1998/Accepted: 25 August 1998     

Metabolic and immunologic consequences of laparoscopy with helium or carbon dioxide insufflation: a randomized clinical study

Background : Previous studies using animal models have demonstrated that carbon dioxide (CO₂) pneumoperitoneum during laparoscopy is associated with adverse physiological, metabolic, immunological and oncological effects, and many of these problems can be avoided by the use of helium insufflation. The present study was performed in patients to compare the effect of helium and CO₂ insufflation on intraperitoneal markers of immunological and metabolic function. Methods : Eighteen patients undergoing elective upper gastrointestinal laparoscopic surgery were randomized to have insufflation achieved by using either helium (n = 8) or CO₂ (n = 10) gas. Intraperitoneal pH was monitored continuously during surgery, and peritoneal macrophage function was determined by harvesting peritoneal macrophages at 5 min and 30 min after commencing laparoscopy, and then assessing their ability to produce tumour necrosis factor‐α (TNF‐α), and their phagocytic function. Results : Carbon dioxide laparoscopy was associated with a lower intraperitoneal pH at the commencement of laparoscopy, although this difference disappeared as surgery progressed. The production of TNF‐α was better preserved by CO₂ laparoscopy, but the insufflation gas used did not affect macrophage phagocytosis. Patients undergoing helium laparoscopy required less postoperative analgesia. Conclusion : The choice of insufflation gas can affect intraperitoneal macrophage function in the clinical setting, and possibly acid–base balance. The present study suggested no immunological advantages for the clinical use of helium as an insufflation gas. The outcomes of the present study, however, are different to those obtained from previous laboratory studies and further research is needed to confirm this outcome.     

Use of abdominal wall retractor Laparo Tenser in gasless laparoscopic cholecystectomy

High pressure CO2-peritoneum for laparoscopic surgery is not indicated in patients with impairment of cardiorespiratory and renal function and in high risk patients and in obesity. On the other site the uncontrolled abdominal insufflation and the blind insertion of the first trocar in patients with extended intraperitoneal adhesions, often cause bleeding and the intestinal loops dislocation, and can determine visceral lesions. In these patients gasless technique with an abdominal laparolifter can be employed. We report an experience of 36 patients undergoing laparoscopic cholecystectomy by a subcutaneous planar retractor. It was observed a good operative exposure in 83.3%; the surgery was safely performed in 88.8%. Two suprafascial hematoma related to the insertion of the needles of the Laparo Tenser occurred. A regular post-operative discharge was observed in 84.4%. These good results supports the extension of the laparoscopic approach for the cholecystectomy to complicated or to high risk patients.     

Besonderheiten bei laparoskopischen Operationen aus anästhesiologischer Sicht

The value of laparoscopic procedures has increased over the last decade. Many patients undergoing laparoscopic surgery also have coexisting diseases. The hemodynamic effects of intraperitoneal carbon dioxide insufflation depend on the extent of intraperitoneal pressure, severity of preexisting cardiopulmonary diseases, volume state of the patient and alterations of acid-base balance due to a capnoperitoneum. In addition to endocrinologic reactions, patient positioning also affects hemodynamic parameters. In high risk patients extended cardiopulmonary monitoring with an arterial line and repeated blood gas analysis is recommended intraoperatively, in addition to assessment of end-expiratory CO(2). In this patient group the intra-abdominal pressure should be maintained in the range of 5-7 mmHg.     

Impact of laparoscopic gases on peritoneal microenvironment and essential parameters of cell function

Several experimental studies confirm the hypotheses that laparoscopic gases influence the development of tumor metastases [12, 14, 23]. The mechanism for this alteration of malignant tumor growth is still unknown. One reason might be an influence of the in sufflation gas on essential cell function regulating parameters. To investigate the changes of the intra- and extracellular milieu, four parameters—extra- and intracellular pH, intracellular free calcium levels, and tissue oxygen partial pressure—were measured during insufflation with carbon dioxide (CO2), helium (He), or a nonhypoxic gas mixture consistent of 80% CO2 and 20% O2. Study design (In vitro experiments) Intracellular calcium and pH levels were measured in DHD/K12/TRb colon adenocarcinoma cells using fluorescence imaging microscopy. (In vivo experiments) Tissue oxygen partial pressure was measured using a flexible micro catheter (Licox CMP) implanted in the abdominal wall of rats. After establishing the pneumoperitoneum an optical system and an aspirator were inserted to control the position of the micro catheter and to aspirate wound exudates for pH measurements of the wound fluid. Results: Creating of pneumoperitoneum with both CO2 and helium caused a decrease in partial pressure of oxygen in the abdominal wall to about 5 mm Hg whereas insufflation with a nonhypoxic gas mixture (80% CO2 and 20% O2) induced no significant changes. The intra- and extra cellular pH values dramatically decreased during CO2 insufflation (7.4 to 6.2) in vitro. Helium caused a pH increase up to 7.6. Free intracellular calcium was enhanced during CO2 insufflation, whereas helium insufflation did not cause any changes in [Ca2+]i. Nevertheless, a significant decrease of [Ca2+]i was observed during reoxygenation following helium-induced hypoxia. Conclusion: Our study demonstrates that insufflation with either CO2 or He causes significant changes of intra- and extracellular parameters regulating essential cell functions such as oxidative phosphorylation to produce ATP, cell proliferation, or onset of apoptosis.     

"Low-pressure" laparoscopic cholecystectomy in high risk patients (ASA III and IV): our experience

The insufflation pressure used for laparoscopic cholecystectomy is usually 12-15 mm Hg, and a pneumoperitoneum with carbon dioxide has a significant effect on both cardiovascular and respiratory function. These effects are transient in young, healthy patients, but may be dangerous in ASA III and IV patients with a poor cardiac reserve. This study was designed to assess the feasibility of performing laparoscopic cholecystectomy at 6.5-8 mm Hg insufflation pressure in "high-risk" patients. Thirteen patients, 10 ASA III and 3 ASA IV, with cholelithiasis, were included in this study The insufflation pressure was 6.5-8 mm Hg, with a 10 degrees anti-Trendelenburg position. The cardiovascular and blood gas variables studied were: mean arterial blood pressure, heart rate, respiratory rate, and end-tidal CO2 pressure. The authors reported no conversions and no intra- or postoperative complications. During insufflation heart rate and mean arterial blood pressure increased minimally if compared with laparoscopic cholecystectomy at 12-15 mm Hg. Pa CO2 increased after insufflation (+5 mm Hg), and the end-tidal CO2 pressure gradient was moderate (3.5 mm Hg) and unchanged during surgery. A low-pressure pneumoperitoneum is feasible for laparoscopic cholecystectomy and minimizes the adverse haemodynamic effects of peritoneal insufflation.     

腹腔镜与后腹腔镜CO2气腹对患者血流动力学及血气的影响

【摘要】目的 探讨经腹腔和经腹膜后腔入路手术CO2气腹对患者血流动力学及血气的影响。 方法 选择经腹腔和经腹膜后腔入路手术患者各50例,监测气腹前、气腹后30min、60min和气腹结束后30min血流动力学和动脉血气的变化。 结果 两组患者组内气腹后30min、60min患者心率(HR)、平均动脉压（MAP）、中心静脉压（CVP）均较气腹前有显著性差异（P<0.05）。组间比较无差异（P>0.05）。两组患者组内气腹后30、60min患者动脉血二氧化碳分压（PaCO2）较气腹前明显增加,pH明显下降（P<0.05）。组间比较腹膜后腔组变化更明显（P<0.05）。结论 经腹膜后腔入路手术CO2气腹对患者血流动力学和动脉血气的影响更大,术中需加强呼吸管理和内环境监测。     

Mechanism of decreased in vitro murine macrophage cytokine release after exposure to carbon dioxide: relevance to laparoscopic surgery.

OBJECTIVE: The objective of this study was to determine the effect of carbon dioxide (CO2) on the function of peritoneal macrophages. SUMMARY BACKGROUND DATA: Laparoscopic surgery is associated with minimal pain, fever, and low levels of inflammatory cytokines. To understand the mechanisms involved, the authors investigated the effect of different gases on murine peritoneal macrophage intracellular pH and correlated these alterations with alterations in LPS-stimulated inflammatory cytokine release. METHODS: Peritoneal macrophages were incubated for 2 hours in air, helium, or CO2, and the effect of the test gas on immediate or next day lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF) and interleukin-1 release compared. Cytosolic pH of macrophages exposed to test gases was measured using single-cell fluorescent imaging. The in vivo effects of test gases were determined in anesthetized rats during abdominal insufflation. RESULTS: Macrophages incubated in CO2 produced significantly less TNF and interleukin-1 in response to LPS compared to incubation in air or helium. Cytokine production returned to normal 24 hours later. Exposure to CO2, but not air or helium, caused a marked cytosolic acidification. Pharmacologic induction of intracellular acidification to similar levels reproduced the inhibitory effect. In vitro studies showed that CO2 insufflation lowered tissue pH and peritoneal macrophage LPS-stimulated TNF production. CONCLUSIONS: The authors propose that cellular acidification induced by peritoneal CO2 insufflation contributes to blunting of the local inflammatory response during laparoscopic surgery.     

腹膜后腹腔镜手术对全麻患者呼吸及循环的影响

目的:了解腹膜后腹腔镜手术对全麻患者呼吸及循环的影响。方法:选择60例患者择期行腹膜后腹腔镜泌尿外科手术,ASAⅠ～Ⅱ级。观察气腹前、气腹后30、60、90min的MAP、HR、pH、PaCO2、PETCO2、Pa-PETCO2的变化。结果:气腹后患者MAP和HR无显著变化(P>0.05),气腹后较气腹前pH降低,PaCO2、PETCO2、Pa-PETCO2升高(P<0.05),气腹后各时间点以上指标无显著差异(P>0.05)。结论:气腹后PaCO2、PETCO2上升,pH下降,但不呈进行性的变化。     

Comparison between intraperitoneal CO2 insufflation and abdominal wall lift on QT dispersion and rate-corrected QT dispersion during laparoscopic cholecystectomy

This study compared the effect of intraperitoneal CO2 insufflation with abdominal wall lift on RR interval, QT interval, the rate-corrected QT (QTc) interval, QT dispersion (QTD), and the rate-corrected QTD (QTcD) using computerized measurement during laparoscopic cholecystectomy. Thirty patients scheduled for laparoscopic cholecystectomy were randomly assigned to 2 groups: intraperitoneal CO2 insufflation (CO2 group) or abdominal wall lift (lift group). A 12-lead electrocardiogram was monitored to measure parameters. The RR interval, QT interval, and QTc interval did not change significantly during the study in both groups. The QTD and QTcD in the CO2 group increased significantly during CO2 insufflation, and were significantly higher than those of the lift group. Statistically significant increases of QTD and QTcD, which are associated with an increased risk of arrhythmias and cardiac events, occur during CO2 insufflation, and QTD and QTcD in the CO2 group were significantly higher than those of the lift group.     

Arterial to end-tidal carbon dioxide tension difference during laparoscopic colorectal surgery

BACKGROUND: Determination of end-tidal carbon dioxide pressure (PET(CO2)) is effective to confirm adequate ventilation, because arterial to end-tidal carbon dioxide tension difference (deltaa-ET(CO2)) does not change normally during operation. But deltaa-ET(CO2) may change during laparoscopic surgery, because peritoneal insufflation of CO2 will increase CO2 production and reduce functional residual volume. Changes in deltaa-ET(CO2) were reported in laparoscopic cholecystectomy with cardiovascular complication, but there is controversy about how deltaaET(CO2) will change in more complicated and long laparoscopic surgery. In this prospective study, we examined changes in deltaa- ET(CO2) during laparoscopic colorectal surgery. METHODS: Fifty patients received combined general and epidural anesthesia. CO2 pneumoperitoneum was initiated after obtaining arterial blood for gas analysis. Mechanical ventilation was used to maintain PET(CO2) at a stable value between 30 and 40 mmHg during the procedure. Arterial blood gas analysis was performed 10, 60, 120 minutes after CO2 insufflation, and 10 minutes after the termination of insufflation. RESULTS: The mean +/- SD for deltaa-ET(CO2) was 5.8 +/- 4.1 before pneumoperitoneum, 7.1 +/- 4.8, 8.1 +/- 5.4, 6. 4 +/- 4.9 in 10, 60, 120 minutes after pneumoperitoneum, and 6.4 +/- 4.9 in 10 minutes after the termination of pneumoperitoneum. deltaa-ET(CO2) increased significantly during pneumoperitoneum, but did not increase further even if CO2 insufflation was longer than 60 minutes. CONCLUSIONS: In laparoscopic colorectal surgery, Pa(CO2) should be checked for at least the first 60 minutes to confirm adequate ventilation.     

Arterial to end-tidal carbon dioxide pressure difference during laparoscopic surgery in pregnancy

BACKGROUND: There is controversy about whether capnography is adequate to monitor pulmonary ventilation to reduce the risk of significant respiratory acidosis in pregnant patients undergoing laparoscopic surgery. In this prospective study, changes in arterial to end-tidal carbon dioxide pressure difference (PaCO2--PetCO2), induced by carbon dioxide pneumoperitoneum, were determined in pregnant patients undergoing laparoscopic cholecystectomy. METHODS: Eight pregnant women underwent general anesthesia at 17-30 weeks of gestation. Carbon dioxide pnueumoperitoneum was initiated after obtaining arterial blood for gas analysis. Pulmonary ventilation was adjusted to maintain PetCO2 around 32 mmHg during the procedure. Arterial blood gas analysis was performed during insufflation, after the termination of insufflation, after extubation, and in the postoperative period. RESULTS: The mean +/- SD for PaCO2--PetCO2 was 2.4 +/- 1.5 before carbon dioxide pneumoperitoneum, 2.6 +/- 1.2 during, and 1.9 +/- 1.4 mmHg after termination of pneumoperitoneum. PaCO2 and pH during pneumoperitoneum were 35 +/- 1.7 mmHg and 7.41 +/- 0.02, respectively. There were no significant differences in either mean PaCO2--PetCO2 or PaCO2 and pH during various phases of laparoscopy. CONCLUSIONS: Capnography is adequate to guide ventilation during laparoscopic surgery in pregnant patients. Respiratory acidosis did not occur when PetCO2 was maintained at 32 mmHg during carbon dioxide pneumoperitoneum.     

Anaesthesia,minimally invasive surgery and pregnancy

Minimally invasive surgery is being performed more frequently in pregnant patients. Numerous published reports have documented the safety and advantages of laparoscopic cholecystectomy and laparoscopic appendectomy during pregnancy. Pregnancy is associated with a variety of changes in the respiratory and cardiovascular systems, which make the parturient undergoing laparoscopic surgery particularly susceptible to hypoxia, hypercarbia and hypotension. This chapter provides a review of those physiological changes of pregnancy of particular concern for anaesthesiologists, and of the physiological responses to intra-abdominal carbon dioxide insufflation, not only in healthy patients, but also in the altered physiological state associated with pregnancy. We also describe our approach to anaesthetic management for minimally invasive surgery during pregnancy. With appropriate precautions, including vigilant monitoring and anticipation and treatment of the potential adverse effects of carbon dioxide pneumoperitoneum, anaesthesiologists may provide safe care for these patients, and pregnant women can benefit from the advantages of minimally invasive surgery.