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

Moderate Intra-Abdominal Pressure Levels in Robot-Assisted Radical Prostatectomy Seem to Have No Negative Impact on Clinical Outcomes

Introduction: Radical prostatectomy is increasingly performed laparoscopically with robot assistance (RALRP). RALRP, as with all laparoscopic procedures, requires a pneumoperitoneum, which might result in peritoneal inflammatory response reactions and postoperative pain. The aim of this retrospective single-centre study was to analyse the effects of a pneumoperitoneum during RARLP on clinical outcomes. Methods: All patients who underwent robot-guided prostatectomy in our clinic were included, with the exception of patients who were converted to open prostatectomy. C-reactive protein was used as a marker for the primary outcome, namely the postoperative inflammatory response. Intra-abdominal pressure (IAP) was evaluated as a potential factor influencing inflammation. In addition, the waist-hip ratio was used to estimate the amount of visceral adipose tissue, and the administration of dexamethasone was considered as a factor influencing inflammation. The Visual Analogue Scale (VAS) was used to determine postoperative pain. Patients were consecutively recruited between 1 September 2020 and 31 March 2022. Results: A total of 135 consecutive patients were included. The median waist-hip ratio was 0.55. The median duration of the pneumoperitoneum was 143 min. The median values of the average and maximum IAP values were 10 mmHg and 15 mmHg, respectively. The mean CRP of the first postoperative day was 6.2 mg/dL. The median VAS pain level decreased from 2 to 1 from the first to the third postoperative day. On the first postoperative day, 16 patients complained of shoulder pain. In addition, 134 patients were given some form of opioid pain treatment following surgery. Conclusion: We could not identify any relevant associations between the duration and IAP of the pneumoperitoneum and the indirect markers of inflammation or indicators of pain, or between the latter and the amount of visceral adipose tissue. In addition, we found no significant effect of the administration of dexamethasone on postoperative inflammation. The results point to a noninferior tolerability of moderate pressure during the procedure compared to the commonly utilised higher pressure, yet this must be confirmed in randomised controlled trials.

Premedication with acetazolamide: Is its use for postoperative pain and stress control after laparoscopic ovariectomy in dogs ruled out?

BACKGROUND

Studies in human medicine have concluded that acetazolamide reduces pain associated with carbon dioxide insufflation during laparoscopic surgery. However, there are no published reports regarding the use of acetazolamide for this purpose in companion animals, despite the increasing popularity of laparoscopic techniques in veterinary medicine due to their advantages over open surgeries.

OBJECTIVES

Thirty mixed-breed female dogs were included in the study and randomly assigned to one of three groups: OVE (median celiotomy ovariectomy; n = 10), OVEL (laparoscopic ovariectomy, n = 10) and OVELA (laparoscopic ovariectomy with acetazolamide preoperative administration; n = 10). Experienced surgeons performed all procedures, and the anaesthetic and analgesic protocols were identical for all animals. Acetazolamide was administered orally (at a dose of 25 mg/kg) 2 h prior to induction in the OVELA group. Postoperative pain was evaluated using serum cortisol, salivary cortisol, and the University of Melbourne Pain Scale (UMPS) Score.

RESULTS

Any statistical differences were observed in the UMPS scores when the OVELA group was compared to the OVEL group at 1 h after surgery (p = 0.515), 12 h (p = 0.375) and 24 h (p = 0.242). Animals undergoing open surgery (OVE group) had significantly higher pain scores at all times after surgery when compared with OVEL and OVELA groups. A high positive correlation (r = 0.792; p = 0.01) was found between serum and saliva cortisol concentrations. Mean saliva cortisol concentration was not significantly lower for the OVELA group compared to the other groups.

CONCLUSIONS

This study found evidence that preoperative administration of acetazolamide may be beneficial in managing postoperative pain in dogs after laparoscopic surgeries. However, further research with a larger sample size is needed to confirm this and to determine if acetazolamide should be included in a multimodal postoperative analgesia protocol for laparoscopic ovariectomy in dogs.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery

BACKGROUND

This is the second update of a Cochrane Review first published in 2013 and last updated in 2017. Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum.

OBJECTIVES

To assess the safety, benefits, and harms of different gases (e.g. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic abdominal or gynaecological pelvic surgery.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, four other databases, and three trials registers on 15 October 2021 together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 10 RCTs, randomising 583 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (four trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. All the RCTs were single-centre studies. Four RCTs were conducted in the USA; two in Australia; one in China; one in Finland; one in Iran; and one in the Netherlands. The mean age of the participants ranged from 27.6 years to 49.0 years. Four trials randomised participants to nitrous oxide pneumoperitoneum (132 participants) or carbon dioxide pneumoperitoneum (128 participants). None of the trials was at low risk of bias. The evidence is very uncertain about the effects of nitrous oxide pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto odds ratio (OR) 2.62, 95% CI 0.78 to 8.85; 3 studies, 204 participants; very low-certainty evidence), or surgical morbidity (Peto OR 1.01, 95% CI 0.14 to 7.31; 3 studies, 207 participants; very low-certainty evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (4 studies, 260 participants; very low-certainty evidence). Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. The evidence is very uncertain about the effects of helium pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto OR 1.66, 95% CI 0.28 to 9.72; 3 studies, 128 participants; very low-certainty evidence), or surgical morbidity (5 studies, 177 participants; very low-certainty evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (3 studies, 128 participants; very low-certainty evidence). One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at high risk of bias. There were no cardiopulmonary complications, serious adverse events, or deaths observed related to either room air or carbon dioxide pneumoperitoneum.    AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of nitrous oxide, helium, and room air pneumoperitoneum compared to carbon dioxide pneumoperitoneum on any of the primary outcomes, including cardiopulmonary complications, surgical morbidity, and serious adverse events. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established, especially in people with high anaesthetic risk.

The "Dark Side" of Pneumoperitoneum and Laparoscopy

Laparoscopic surgery has been one of the most common procedures for abdominal surgery at pediatric age during the last few decades as it has several advantages compared to laparotomy, such as shorter hospital stays, less pain, and better cosmetic results. However, it is associated with both local and systemic modifications. Recent evidence demonstrated that carbon dioxide pneumoperitoneum might be modulated in terms of pressure, duration, temperature, and humidity to mitigate and modulate these changes. The aim of this study is to review the current knowledge about animal and human models investigating pneumoperitoneum-related biological and histological impairment. In particular, pneumoperitoneum is associated with local and systemic inflammation, acidosis, oxidative stress, mesothelium lining abnormalities, and adhesion development. Animal studies reported that an increase in pressure and time and a decrease in humidity and temperature might enhance the rate of comorbidities. However, to date, few studies were conducted on humans; therefore, this research field should be further investigated to confirm in experimental models and humans how to improve laparoscopic procedures in the spirit of minimally invasive surgeries.

Pneumoperitoneum Modifies Serum and Tissue CCL2-CCL5 Expression in Mice

Background and Objectives:

Laparoscopy is the preferred method when operating in the abdomen. In this study, we evaluated systemic and morphological peritoneal cytokine modifications (RANTES/CCL5 and MCP-1/CCL2) due to CO₂ pneumoperitoneum in rats.

Methods:

Twenty-five prepubertal Sprague-Dawley rats were randomized into three groups. Pneumoperitoneum lasting 30 minutes, was induced with a flow of 0.5 L/min, in two groups (S1 and S2, n = 20), at a P/CO₂ of 6 and 10 mm Hg, respectively. In the control group (C, n = 5), only anesthesia was carried out. All animals were sacrificed after 24 hours. The serum of the rats was collected for ELISA, and the levels of the cytokines RANTES and MCP-1 were investigated. An immunohistochemical analysis of RANTES and MCP-1 was performed on samples of the peritoneum, and the morphological evaluation was conducted with a blinded evaluation by two independent, experienced pathologists by using a grading system (0, 1+, 2+, 3+: no, faint, moderate, and strong reactivity, respectively).

Results:

RANTES mean levels were significantly different in the S1, S2, and C groups (70.3 ± 2.26, 58.23 ± 4.32, 29.66 ± 4.03, respectively, P = .0001). The levels of MCP-1 were 32.1 ± 1.63 in the S1 group, 27.0 ± 9.26 in the S2 group, and 16.4 ± 9.55 in the C group (P = .159). Normal control peritoneum showed little reactivity, whereas a moderate to strong cytoplasmic reaction to anti-CCL5/CCL2 antibodies was observed in mesothelial and inflammatory cells in the S1 and S2 groups.

Conclusion:

CO₂ pneumoperitoneum evokes an inflammatory response by modifying plasma RANTES levels and peritoneal CCL5/CCL2 expression.

Pain after laparoscopic surgery: Focus on shoulder-tip pain after gynecological laparoscopic surgery

Laparoscopy, one of minimally invasive procedures, is a commonly used procedure in diagnosis and management of various kinds of clinical problems, including gynecologic organ-related diseases. Compared with conventional exploratory laparotomy, the benefits of laparoscopic surgery include reduction of surgical wound, decreasing in postoperative pain, shortening hospital stay, rapid recovery, and a better cosmetic result. However, there are still up to 80% of patients after laparoscopic surgery complaining of high levels of pain and needing pain relief. Postlaparoscopic pain can be separated into distinct causes, such as surgical trauma- or incision wound-associated inflammatory change, and pneumoperitoneum (carbon dioxide [CO2])-related morphological and biochemical changes of peritoneum and diaphragm. The latter is secondary to irritation, stretching, and foreign body stimulation, leading to phrenic neuropraxia and subsequent shoulder-tip pain (STP). STP is the most typical unpleasant experience of patients after laparoscopic surgery. There are at least 11 strategies available to attempt to decrease postlaparoscopic STP, including (1) the use of an alternative insufflating gas in place of CO2, (2) the use of low-pressure pneumoperitoneum in place of standard-pressure pneumoperitoneum, (3) the use of warmed or warmed and humidified CO2, (4) gasless laparoscopy, (5) subdiaphragmatic intraperitoneal anesthesia, (6) local intraperitoneal anesthesia, (7) actively expelling out of gas, (8) intraperitoneal drainage, (9) fluid instillation, (10) pulmonary recruitment maneuvers, and (11) others and combination. The present article is limited in discussing postlaparoscopic STP. We extensively review published articles to provide a better strategy to reduce postlaparoscopic STP.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery

BACKGROUND

This is an update of the review published in 2013.Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. People with high anaesthetic risk are more likely to experience cardiopulmonary complications and adverse events, for example hypercapnia and acidosis, which has to be avoided by hyperventilation. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum.

OBJECTIVES

To assess the safety, benefits, and harms of different gases (i.e. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic general abdominal or gynaecological pelvic surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 9), Ovid MEDLINE (1950 to September 2016), Ovid Embase (1974 to September 2016), Science Citation Index Expanded (1970 to September 2016), Chinese Biomedical Literature Database (CBM) (1978 to September 2016), ClinicalTrials.gov (September 2016), and World Health Organization International Clinical Trials Registry Platform (September 2016).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated risk ratio (RR) for dichotomous outcomes (or Peto odds ratio for very rare outcomes), and mean difference (MD) or standardised mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI). We used GRADE to rate the quality of evidence, MAIN RESULTS: We included nine RCTs, randomising 519 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (three trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. Three trials randomised participants to nitrous oxide pneumoperitoneum (100 participants) or carbon dioxide pneumoperitoneum (96 participants). None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of nitrous oxide and carbon dioxide on cardiopulmonary complications (RR 2.00, 95% CI 0.38 to 10.43; two studies; 140 participants; very low quality of evidence), or surgical morbidity (RR 1.01, 95% CI 0.18 to 5.71; two studies; 143 participants; very low quality of evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (three studies; 196 participants; very low quality of evidence). We could not combine data from two trials (140 participants) which individually showed lower pain scores (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain) with nitrous oxide pneumoperitoneum at various time points on the first postoperative day, and this was rated asvery low quality .Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of helium or carbon dioxide on cardiopulmonary complications (RR 1.46, 95% CI 0.35 to 6.12; three studies; 128 participants; very low quality of evidence) or pain scores (visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain; MD 0.49 cm, 95% CI -0.28 to 1.26; two studies; 108 participants; very low quality of evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (three studies; 128 participants; very low quality of evidence).One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at unclear risk of bias. There were no cardiopulmonary complications or serious adverse events observed related to either room air or carbon dioxide pneumoperitoneum (both outcomes very low quality of evidence). The evidence of lower hospital costs and reduced pain during the first postoperative day with room air pneumoperitoneum compared with carbon dioxide pneumoperitoneum (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain, was rated as very low quality of evidence.

AUTHORS' CONCLUSIONS

The quality of the current evidence is very low. The effects of nitrous oxide and helium pneumoperitoneum compared with carbon dioxide pneumoperitoneum are uncertain. Evidence from one trial of small sample size suggests that room air pneumoperitoneum may decrease hospital costs in people undergoing laparoscopic abdominal surgery. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established.Further trials on this topic are needed, and should compare various gases (i.e. nitrous oxide, helium, argon, nitrogen, and room air) with carbon dioxide under standard pressure pneumoperitoneum with cold gas insufflation for people with high anaesthetic risk. Future trials should include outcomes such as complications, serious adverse events, quality of life, and pain.

Effects of low and standard intra-abdominal pressure on systemic inflammation and immune response in laparoscopic adrenalectomy: A prospective randomised study

BACKGROUND:

The advantages of laparoscopic adrenalectomy (LA) over open adrenalectomy are undeniable. Nevertheless, carbon dioxide (CO₂) pneumoperitoneum may have an unfavourable effect on the local immune response. The aim of this study was to compare changes in the systemic inflammation and immune response in the early post-operative (p.o.) period after LA performed with standard and low-pressure CO₂ pneumoperitoneum.

MATERIALS AND METHODS:

We studied, in a prospective randomised study, 51 patients consecutively with documented adrenal lesion who had undergone a LA: 26 using standard-pressure (12-14 mmHg) and 25 using low-pressure (6-8 mmHg) pneumoperitoneum. White blood cells (WBC), peripheral lymphocyte subpopulation, human leucocyte antigen-DR (HLA-DR), neutrophil elastase, interleukin (IL)-6 and IL-1, and C-reactive protein (CRP) were investigated.

RESULTS:

Significantly higher concentrations of neutrophil elastase, IL-6 and IL-1 and CRP were detected p.o. in the standard-pressure group of patients in comparison with the low-pressure group (P < 0.05). A statistically significant change in HLA-DR expression was recorded p.o. at 24 h, as a reduction of this antigen expressed on the monocyte surface in patients from the standard group; no changes were noted in low-pressure group patients (P < 0.05).

CONCLUSIONS:

This study demonstrated that reducing the pressure of the pneumoperitoneum to 6-8 mmHg during LA reduced p.o. inflammatory response and averted p.o. immunosuppression.

Low pressure versus standard pressure pneumoperitoneum in laparoscopic cholecystectomy

BACKGROUND

A pneumoperitoneum of 12 to 16 mm Hg is used for laparoscopic cholecystectomy. Lower pressures are claimed to be safe and effective in decreasing cardiopulmonary complications and pain.

OBJECTIVES

To assess the benefits and harms of low pressure pneumoperitoneum compared with standard pressure pneumoperitoneum in people undergoing laparoscopic cholecystectomy.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013 to identify randomised trials,using search strategies.

SELECTION CRITERIA

We considered only randomised clinical trials, irrespective of language, blinding, or publication status for inclusion in the review.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials and independently extracted data. We calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) using both fixed-effect and random-effects models with RevMan 5 based on available case analysis.

MAIN RESULTS

A total of 1092 participants randomly assigned to the low pressure group (509 participants) and the standard pressure group (583 participants) in 21 trials provided information for this review on one or more outcomes. Three additional trials comparing low pressure pneumoperitoneum with standard pressure pneumoperitoneum (including 179 participants) provided no information for this review. Most of the trials included low anaesthetic risk participants undergoing elective laparoscopic cholecystectomy. One trial including 140 participants was at low risk of bias. The remaining 20 trials were at high risk of bias. The overall quality of evidence was low or very low. No mortality was reported in either the low pressure group (0/199; 0%) or the standard pressure group (0/235; 0%) in eight trials that reported mortality. One participant experienced the outcome of serious adverse events (low pressure group 1/179, 0.6%; standard pressure group 0/215, 0%; seven trials; 394 participants; RR 3.00; 95% CI 0.14 to 65.90; very low quality evidence). Quality of life, return to normal activity, and return to work were not reported in any of the trials. The difference between groups in the conversion to open cholecystectomy was imprecise (low pressure group 2/269, adjusted proportion 0.8%; standard pressure group 2/287, 0.7%; 10 trials; 556 participants; RR 1.18; 95% CI 0.29 to 4.72; very low quality evidence) and was compatible with an increase, a decrease, or no difference in the proportion of conversion to open cholecystectomy due to low pressure pneumoperitoneum. No difference in the length of hospital stay was reported between the groups (five trials; 415 participants; MD -0.30 days; 95% CI -0.63 to 0.02; low quality evidence). Operating time was about two minutes longer in the low pressure group than in the standard pressure group (19 trials; 990 participants; MD 1.51 minutes; 95% CI 0.07 to 2.94; very low quality evidence).

AUTHORS' CONCLUSIONS

Laparoscopic cholecystectomy can be completed successfully using low pressure in approximately 90% of people undergoing laparoscopic cholecystectomy. However, no evidence is currently available to support the use of low pressure pneumoperitoneum in low anaesthetic risk patients undergoing elective laparoscopic cholecystectomy. The safety of low pressure pneumoperitoneum has to be established. Further well-designed trials are necessary, particularly in people with cardiopulmonary disorders who undergo laparoscopic cholecystectomy.

A prospective randomized study of systemic inflammation and immune response after laparoscopic nissen fundoplication performed with standard and low-pressure pneumoperitoneum

BACKGROUND

The aim of this study was to compare changes in the systemic inflammation and immune response in the early postoperative (p.o.) period after laparoscopic Nissen fundoplication (LNF) was performed with standard-pressure and low-pressure carbon dioxide pneumoperitoneum.

MATERIALS AND METHODS

We studied 68 patients with documented gastroesophageal reflux disease and who underwent a LNF: 35 using standard-pressure (12 to 14 mmHg) and 33 low-pressure (6 to 8 mmHg) pneumoperitoneum. White blood cells, peripheral lymphocytes subpopulation, human leukocyte antigen-DR, neutrophil elastase, interleukin (IL)-6 and IL-1, and C-reactive protein were investigated.

RESULTS

A significantly higher concentration of neutrophil elastase, IL-6 and IL-1, and C-reactive protein was detected postoperatively in the standard-pressure group of patients in comparison with the low-pressure group (P<0.05). A statistically significant change in human leukocyte antigen-DR expression was recorded p.o. at 24 hours, as a reduction of this antigen expressed on monocyte surface in patients from standard group; no changes were noted in low-pressure group patients (P<0.05).

CONCLUSIONS

This study demonstrated that reducing the pressure of the pneumoperitoneum to 6 to 8 mm Hg during LNF is reduced p.o. inflammatory response and avoided p.o. immunosuppression.

Abdominal lift for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy (key-hole removal of the gallbladder) is now the most often used method for treatment of symptomatic gallstones. Several cardiopulmonary changes (decreased cardiac output, pulmonary compliance, and increased peak airway pressure) occur during pneumoperitoneum, which is now introduced to allow laparoscopic cholecystectomy. These cardiopulmonary changes may not be tolerated in individuals with poor cardiopulmonary reserve.

OBJECTIVES

To assess the benefits and harms of abdominal wall lift compared to pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013.

SELECTION CRITERIA

We included all randomised clinical trials comparing abdominal wall lift (with or without pneumoperitoneum) versus pneumoperitoneum.

DATA COLLECTION AND ANALYSIS

We calculated the risk ratio (RR), rate ratio (RaR), or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis with both the fixed-effect and the random-effects models using the Review Manager (RevMan) software.

MAIN RESULTS

For abdominal wall lift with pneumoperitoneum versus pneumoperitoneum, a total of 130 participants (all with low anaesthetic risk) scheduled for elective laparoscopic cholecystectomy were randomised in five trials to abdominal wall lift with pneumoperitoneum (n = 53) versus pneumoperitoneum only (n = 52). One trial which included 25 people did not state the number of participants in each group. All five trials had a high risk of bias. There was no mortality or conversion to open cholecystectomy in any of the participants in the trials that reported these outcomes. There was no significant difference in the rate of serious adverse events between the two groups (two trials; 2/29 events (0.069 events per person) versus 2/29 events (0.069 events per person); rate ratio 1.00; 95% CI 0.17 to 5.77). None of the trials reported quality of life, the proportion of people discharged as day-patient laparoscopic cholecystectomies, or pain between four and eight hours after the operation. There was no significant difference in the operating time between the two groups (four trials; 53 participants versus 54 participants; 13.39 minutes longer (95% CI 2.73 less to 29.51 minutes longer) in the abdominal wall lift with pneumoperitoneum group and 100 minutes in the pneumoperitoneum group).For abdominal wall lift versus pneumoperitoneum, a total of 774 participants (the majority with low anaesthetic risk) scheduled for elective laparoscopic cholecystectomy were randomised in 18 trials to abdominal wall lift without pneumoperitoneum (n = 332) versus pneumoperitoneum (n = 358). One trial which included 84 people did not state the number in each group. All the trials had a high risk of bias. There was no mortality in any of the trials that reported this outcome. There was no significant difference in the proportion of participants with serious adverse events (six trials; 5/172 (weighted proportion 2.4%) versus 2/171 (1.2%); RR 2.01; 95% CI 0.52 to 7.80). There was no significant difference in the rate of serious adverse events between the two groups (three trials; 5/99 events (weighted number of events per person = 0.346 events) versus 2/99 events (0.020 events per person); rate ratio 1.73; 95% CI 0.35 to 8.61). None of the trials reported quality of life or pain between four and eight hours after the operation. There was no significant difference in the proportion of people who underwent conversion to open cholecystectomy (11 trials; 5/225 (weighted proportion 2.3%) versus 7/235 (3.0%); RR 0.76; 95% CI 0.26 to 2.21). The operating time was significantly longer in the abdominal wall lift group than in the pneumoperitoneum group (16 trials; 6.87 minutes longer (95% CI 4.74 minutes to 9.00 minutes longer) in the abdominal wall lift group versus 75 minutes in the pneumoperitoneum group). There was no significant difference in the proportion of people discharged as laparoscopic cholecystectomy day-patients (two trials; 15/31 (weighted proportion 48.5%) versus 9/31 (29%); RR 1.67; 95% CI 0.85 to 3.26).

AUTHORS' CONCLUSIONS

Abdominal wall lift with or without pneumoperitoneum does not seem to offer an advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in people with low anaesthetic risk. Hence it cannot be recommended routinely. The safety of abdominal wall lift is yet to be established. More research on the topic is needed because of the risk of bias in the included trials and because of the risk of type I and type II random errors due to the few participants included in the trials. Future trials should include people at higher anaesthetic risk. Furthermore, such trials should include blinded assessment of outcomes.

Abdominal lift for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy (key-hole removal of the gallbladder) is now the most often used method for treatment of symptomatic gallstones. Several cardiopulmonary changes (decreased cardiac output, pulmonary compliance, and increased peak airway pressure) occur during pneumoperitoneum, which is now introduced to allow laparoscopic cholecystectomy. These cardiopulmonary changes may not be tolerated in individuals with poor cardiopulmonary reserve.

OBJECTIVES

To assess the benefits and harms of abdominal wall lift compared with pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2012.

SELECTION CRITERIA

We included all randomised clinical trials comparing abdominal wall lift (with or without pneumoperitoneum) versus pneumoperitoneum.

DATA COLLECTION AND ANALYSIS

We calculated the risk ratio (RR), rate ratio (RaR), or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis with both the fixed-effect and the random-effects models using RevMan software.

MAIN RESULTS

For abdominal wall lift with pneumoperitoneum versus pneumoperitoneum, a total of 156 participants (all with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in six trials to abdominal wall lift with pneumoperitoneum (n = 65) versus pneumoperitoneum only (n = 66). One trial which included 25 patients did not state the number of patients in each group. All six trials had a high risk of bias. There was no mortality or conversion to open cholecystectomy in any of the patients in the trials that reported these outcomes. There was no significant difference in the rate of serious adverse events between the two groups (2 trials; 2/29 events (0.069 events per patient) versus 2/29 events (0.069 events per patient); rate ratio 1.00; 95% CI 0.17 to 5.77). None of the trials reported quality of life, the proportion of patients discharged as day-patient laparoscopic cholecystectomies, or pain between four and eight hours after the operation. There was no significant difference in the operating time between the two groups (4 trials; 53 patients versus 54 patients; 13.39 minutes longer (2.73 less to 29.51 longer) in the abdominal wall lift with pneumoperitoneum group and 100 minutes in the pneumoperitoneum group).For abdominal wall lift versus pneumoperitoneum, a total of 774 participants (the majority with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in 18 trials to abdominal wall lift without pneumoperitoneum (n = 332) versus pneumoperitoneum (n = 358). One trial which included 84 patients did not state the number of patients in each group. All the trials had a high risk of bias. There was no mortality in any of the trials that reported this outcome. There was no significant difference in the rate of serious adverse events between the two groups (6 trials; 5/172 events (weighted number of events per patient = 0.020 events) versus 2/171 events (0.012 events per patient); rate ratio 1.73; 95% CI 0.35 to 8.61). None of the trials reported quality of life or pain between four and eight hours after the operation. There was no significant difference in the proportion of patients who underwent conversion to open cholecystectomy (11 trials; 5/225 (weighted proportion 2.3%) versus 7/235 (3.0%); RR 0.76; 95% CI 0.26 to 2.21). The operating time was significantly longer in the abdominal wall lift group than the pneumoperitoneum group (16 trials; 6.87 minutes longer (4.74 to 9.00 longer) in the abdominal wall lift group; 75 minutes in the pneumoperitoneum group). There was no significant difference in the proportion of patients who were discharged as day-patient laparoscopic cholecystectomy patients (2 trials; 15/31 (weighted proportion 48.5%) versus 9/31 (29%); RR 1.67; 95% CI 0.85 to 3.26).

AUTHORS' CONCLUSIONS

Abdominal wall lift does not seem to offer an advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in patients with low anaesthetic risk. It may increase costs by increasing the operating time. Hence it cannot be recommended routinely. The safety of abdominal wall lift is yet to be established. More research on the topic is needed because of the risk of bias in the included trials and because of the risk of type I and type II random errors because of the few patients included in the trials. Such trials ought to include patients at higher anaesthetic risk. Furthermore, such trials ought to include blinded assessment of outcome measures.

Application of stereology to study the effects of pneumoperitoneum on peritoneum

BACKGROUND

Scanning electron microscopy is unable to provide sufficient data to obtain definitive results for research into the morphologic effect of pneumoperitoneum on peritoneum. To overcome this difficulty, we adopted stereology to examine the effect of the type of gas insufflated, pressure, duration, and gas flow on morphologic alterations of peritoneum.

METHODS

Fifty SD rats were divided into ten groups. One group served as control. Pneumoperitoneum was established at 5 mmHg and 1.0 l/min gas flow for 1, 2 or 3 h with CO2 (in groups C1h, C2h, and C3h, respectively) or with He (in groups H1h, H2h, and H3h, respectively). CO2 pneumoperitoneum was further established at 8 mmHg and 1.0 l/min gas flow for 1 h (group C8p), at 5 mmHg and 2.0 l/min gas flow for 1 h (group C2f), and at 5 mmHg and 3.0 l/min gas flow for 1 h (group C3f). After the procedures, five specimens were sampled from anterior peritoneum and measured by stereological and electron-microscopic techniques.

RESULTS

Groups H1h and C1h, H2h and C2h, and H3h and C3h, respectively, were the same in terms of area fraction of basal lamina exposed and diameter of mesothelial cells (P>0.05). The magnitudes of peritoneal trauma in groups C2h, C3h, C8p, C2f, and C3f were significantly higher than that in group C1h (P<0.01), and the same result was observed in groups H2h and H3h against group H1h (P<0.01), and in group C3f against group C2f (P<0.01). Furthermore, the area fractions of basal lamina exposed in groups C3h and H3h were remarkably higher than those in groups C2h and H2h, respectively (P<0.01). The mechanism of basal lamina exposure comprises mesothelial cell desquamation and plasmatorrhexis.

CONCLUSIONS

Peritoneal morphologic trauma during pneumoperitoneum can be attributed to the pressure, duration, and gas flow instead of the type of gas insufflated.

Tumor implantation during laparoscopy using different insufflation gases – an experimental study using cultured cancer cells

Recent work using an experimental model in our laboratory has shown that the likelihood of tumor implantation at laparoscopy port-sites following laparoscopy might be influenced by the specific gas used for insufflation. In particular helium insufflation was associated with less port site metastases. The model entailed an inbred rat strain and a tumor cell suspension of mixed heterogeneity, native to the rat strain. To determine whether our previous findings could be reproduced using a different model, we investigated the effect of insufflation with either helium or carbon dioxide gas on the implantation of a purified cell suspension of cultured cancer cells. Thirty-eight Dark Agouti rats were randomized to undergo a 40 minute period of laparoscopic insufflation with either helium or carbon dioxide (19 animals in each group/three different experiments). Three laparoscopy ports were placed and 2 x 10<dformgrp> <dformula> 5 </dformula> </dformgrp> cultured mammary adenocarcinoma cells were introduced into the abdominal cavity at the beginning of the period of insufflation. The rats were killed nine days after surgery and the port sites and abdominal cavity were examined for presence of tumor. Rats undergoing helium insufflation were equally likely to develop port-site metastases compared to rats undergoing carbon dioxide insufflation. There was, however, a predilection for port site metastases to develop at the port site used for camera placement in both groups. Because this port site accommodated a 2 mm laparoscope, it was associated with a larger wound than the other two port sites. Peritoneal tumor deposits elsewhere in the peritoneal cavity were more common following helium insufflation, compared to carbon dioxide. The outcome of this study is different to the results from previous studies using a heterogeneous tumor cell suspension in the same model in our laboratory, or elsewhere, with no advantages demonstrated for insufflation with helium gas. Purified cell suspensions could behave differently to a heterogeneous cell suspension of identical cancer cells in a port-site implantation model, and other cells present within heterogeneous tumor suspension might influence the likelihood of metastasis. As reported previously, tumor implantation is more likely in larger port site wounds and this is independent of the insufflation gas.

Low pressure versus standard pressure pneumoperitoneum in laparoscopic cholecystectomy

BACKGROUND

A pneumoperitoneum of 12 to 16 mmHg is used for laparoscopic cholecystectomy. Lower pressures are claimed to be safe and effective in decreasing cardiopulmonary complications and pain.

OBJECTIVES

To assess the benefits and harms of low pressure pneumoperitoneum compared with standard pressure pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until November 2008 for identifying randomised trials using search strategies.

SELECTION CRITERIA

Only randomised clinical trials, irrespective of language, blinding, or publication status were considered for the review.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials and independently extracted data on mortality, morbidity, conversion to open cholecystectomy, pain, analgesic requirement, operating time, hospital stay, patient satisfaction, additional measures to increase vision, and cardiopulmonary parameters. We calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) using both the fixed-effect and the random-effects models with RevMan 5 based on available case-analysis.

MAIN RESULTS

Fifteen trials randomised 690 patients to low pressure (n = 336) and standard pressure (n = 354). All the trials were of high risk of bias. There was no difference in the mortality, morbidity, or conversion to open cholecystectomy between the groups. The intensity of pain was lower in the low pressure group at various time points. The incidence of shoulder pain was lower in the low pressure group (RR 0.53; 95% CI 0.31 to 0.90). The analgesic consumption was also lower. The operating time was similar between the groups (MD 2.30 minutes; 95% CI 0.42 to 4.18). Because of the high risk of bias due to incomplete outcome data in seven trials, it was not possible to conclude about the safety of low pressure pneumoperitoneum.

AUTHORS' CONCLUSIONS

Low pressure pneumoperitoneum appears effective in decreasing pain after laparoscopic cholecystectomy. The safety of low pressure pneumoperitoneum has to be established.

Esophageal and gastric smooth muscle activity after carbon dioxide pneumoperitoneum

BACKGROUND

The metabolic changes associated with carbon dioxide (CO(2)) pneumoperitoneum include metabolic acidosis and lowered intra-abdominal pH values. An experimental study was performed to evaluate the effect of CO(2) pneumoperitoneum on esophageal and gastric smooth muscle sensitivity in response to several agonists.

METHODS

Wistar albino rats, weighing 200-250 g, were allocated into three groups. After anesthetization with ketamine hydrochloride and xylazine, abdominal esophagus, gastroesophageal junction, and gastric fundus were removed via median laparotomy in the control group. In the oxygen (O(2)) group, a 16G catheter was inserted into the abdomen above the umbilicus and insufflated with 95% O(2) and 5% CO(2) with a pressure of 10 mm Hg. In the CO(2) group, CO(2) was insufflated at the same pressure within the same time and the tissues were removed at the end of a 60 min period of pneumoperitoneum. Abdominal esophageal segment (n:6), gastroesophageal junction (n:6) and gastric fundus (n:12) were suspended under 0.5 to 2 g resting tension in Tyrode solution in organ baths. Contraction responses were obtained by carbachol and serotonin and relaxation responses were evaluated by isoproterenol in each group. All the responses were compared by nonparametric Kruskal Wallis test.

RESULTS

Carbachol and serotonin induced contractile responses of abdominal segments, gastroesophageal junction, and gastric fundus showed no difference between the control, O(2), and CO(2) groups (P > 0.05). Isoproterenol relaxation responses of the three groups were also not statistically different from each other (P > 0.05).

CONCLUSION

CO(2) pneumoperitoneum of 60 min has no influence on esophageal and gastric smooth muscle responses to different agonists in rats.

Heated and humidified CO2 prevents hypothermia, peritoneal injury, and intra-abdominal adhesions during prolonged laparoscopic insufflations

BACKGROUND

Insufflation with standard cold-dry CO(2) during laparoscopic surgery has been shown to predispose patients to hypothermia and peritoneal injury. This study aimed to compare the effect of prolonged cold-dry CO(2) insufflation with heated-humidified CO(2) insufflation (3-5 h) on hypothermia, peritoneal damage, and intra-abdominal adhesion formation in a rat model.

MATERIALS AND METHODS

A total of 160 Wistar rats were randomized to undergo no insufflation or insufflation with cold-dry CO(2) (21 degrees C, <1% relative humidity) or heated-humidified CO(2) (37 degrees C, 95% relative humidity) for 3, 4, or 5 h. Core body temperature was measured via rectum before and during insufflations. Peritoneal samples were taken at 6, 24, 48, and 96 h after treatments and analyzed with light microscopy and scanning electron microscopy. Intra-abdominal adhesions were evaluated 2 weeks later.

RESULTS

Core body temperature significantly decreased in the cold-dry group, whereas it was maintained and increased in the heated-humidified group. Scanning electron microscopy and light microscopy studies showed intense peritoneal injury in the cold-dry CO(2) group but significantly less damages in the heated-humidified group. Increased intra-abdominal adhesion formation was observed in the cold-dry CO(2) group, while no adhesions were found in the rats insufflated with heated-humidified CO(2).

CONCLUSIONS

Heated-humidified CO(2) insufflation results in significantly less hypothermia, less peritoneal damage, and decreased adhesion formation as compared with cold-dry CO(2) insufflation. Heated-humidified CO(2) may be more suitable for insufflation application in prolonged laparoscopic surgery.

Abdominal lift for laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy is the main method of treatment of symptomatic gallstones. Several cardiopulmonary changes (decreased cardiac output, pulmonary compliance, and increased peak airway pressure) occur during pneumoperitoneum. These changes may not be tolerated in individuals with poor cardiopulmonary reserve.

OBJECTIVES

To assess the benefits and harms of abdominal wall lift compared to pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and Science Citation IndexExpanded until January 2007.

SELECTION CRITERIA

We included all randomised clinical trials comparing abdominal wall lift (with or without pneumoperitoneum) and pneumoperitoneum.

DATA COLLECTION AND ANALYSIS

We calculated the relative risk (RR), weighted mean difference (WMD) or standardised mean difference (SMD) with 95% confidence intervals (CI) based on intention-to-treat analysis with both the fixed-effect and the random-effects model using RevMan Analysis.

MAIN RESULTS

Abdominal wall lift with pneumoperitoneum versus pneumoperitoneum. A total of 156 participants (all with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in six trials to abdominal wall lift with pneumoperitoneum (n = 65) versus pneumoperitoneum only (n = 66). One trial which included 25 patients did not state the number of patients in each group. All six trials were of high risk of bias. The cardiopulmonary changes were less in abdominal wall lift than pneumoperitoneum. There was no difference in the morbidity and pain between the groups. Abdominal wall lift versus pneumoperitoneum. A total of 550 participants (the majority with low anaesthetic risk) who underwent elective laparoscopic cholecystectomy were randomised in fourteen trials to abdominal wall lift without pneumoperitoneum (n = 268) versus pneumoperitoneum (n = 282). Two of these fourteen trials were of low risk of bias. The cardiopulmonary changes were less in abdominal wall lift than with pneumoperitoneum. There was no difference in the morbidity and pain between the groups. The operating time was prolonged in abdominal wall lift compared with pneumoperitoneum (WMD 7.74, 95% CI 1.37 to 14.12).

AUTHORS' CONCLUSIONS

(1) Abdominal wall lift seems safe and decreases the cardiopulmonary changes associated with laparoscopic cholecystectomy.(2) Abdominal wall lift does not seem to offer advantage over pneumoperitoneum in any of the patient-oriented outcomes for laparoscopic cholecystectomy in patients with low anaesthetic risk and may increase costs by increasing the operating time. Hence it cannot be recommended routinely. More research on the topic is needed.

Changes in pH of peritoneal fluid associated with carbon dioxide insufflation during laparoscopic surgery in dogs

OBJECTIVE

To evaluate changes in pH of peritoneal fluid associated with CO2 insufflation during laparoscopy in dogs.

ANIMALS

13 client-owned dogs and 10 purpose-bred teaching dogs.

PROCEDURES

Laparotomy was performed on control dogs; peritoneal fluid pH was measured at time of incision of the abdominal cavity (time 0) and 30 minutes later. Laparoscopic insufflation with CO2 was performed and routine laparoscopic procedures conducted on the teaching dogs. Insufflation pressure was limited to 12 mm Hg. Intraperitoneal fluid pH was measured by use of pH indicator paper at 4 time points. Arterial blood gas analysis was performed at the same time points.

RESULTS

Peritoneal fluid pH did not change significantly between 0 and 30 minutes in the control dogs. For dogs with CO2 insufflation, measurements obtained were a mean of 8.5, 24.5, 44.5, and 72.0 minutes after insufflation. The pH of peritoneal fluid decreased significantly between the first (7.825 +/- 0.350) and second (7.672 +/- 0.366) time point. Blood pH decreased significantly between the first (7.343 +/- 0.078), third (7.235 +/- 0.042), and fourth (7.225 +/- 0.038) time points. The PaCO2 increased significantly between the first (39.9 +/- 9.8 mm Hg) and fourth (54.6 +/- 4.4 mm Hg) time points. Base excess decreased significantly between the first and all subsequent time points.

CONCLUSIONS AND CLINICAL RELEVANCE

Pneumoperitoneum attributable to CO2 insufflation caused a mild and transient decrease in peritoneal fluid pH in dogs. Changes in peritoneal fluid associated with CO2 insufflation in dogs were similar to those in other animals.

Improved abdominal wall wound healing by helium pneumoperitoneum

BACKGROUND

Despite widespread use of the endoscopic technique in the treatment of inguinal and incisional hernias, knowledge about its impact on abdominal wall wound healing is rare. Questions remain regarding the risk of port-site hernias and hernia recurrence. The current study investigated the gas-dependent effects of pneumoperitoneum on laparotomy wound healing.

METHODS

Laparotomy was performed in 54 male Sprague-Dawley rats. A carbon dioxide (n = 18) or helium (n = 18) pneumoperitoneum of 3 mmHg was maintained before and after laparotomy, with an overall duration of 30 min. The rats in the control group (n = 18) received no pneumoperitoneum. The animals were killed after 5 and 10 days, and the abdominal wall was explanted for subsequent histopathologic examinations of the laparotomy wound. The granuloma formation in hematoxylin and eosin-stained sections was analyzed. Infiltration of macrophages (CD68) and expression of matrix metalloproteinases (MMP-8 and MMP-13) were examined by immunohistochemistry. The collagen type 1 to type 3 ratio was investigated by cross-polarization microscopy after Sirius Red staining.

RESULTS

After 5 and 10 days, the percentages of CD68-positive cells, granuloma formation, and expression of MMP-8 did not differ between the groups. In contrast, after both 5 and 10 days, the expression of MMP-13 and the collagen 1 to 3 ratio were significantly higher after helium pneumoperitoneum than in the control animals.

CONCLUSION

The results suggest that helium pneumoperitoneum may ameliorate wound healing within the abdominal wall and could therefore represent a beneficial gas for endoscopic hernia repair.

Physiological responses to endoscopic surgery in children

The knowledge on the physiological impact of endoscopic surgery in infants and children is limited. Cardiovascular effects of pneumoperitoneum are mainly the result of an increase in intraabdominal pressure, absorption of carbon dioxide, and a stimulation of the neurohumoral vasoactive system. In infants, pneumoperitoneum alters the heart rate, mean arterial pressure, left ventricular endsystolic and end-diastolic volume, and meridional wall stress. Urine production is significantly reduced, and cerebral oxygenation and blood flow are altered. However, postoperative immune function is preserved or restored faster, and specific physiological responses to endoscopic surgery are well tolerated by otherwise healthy infants and children. The effects in children with specific conditions, such as sepsis, cancer, or organ dysfunction, remain to be investigated.

Peritoneal acidosis mediates immunoprotection in laparoscopic surgery

BACKGROUND

We have shown previously that abdominal insufflation with CO(2) increases serum levels of IL-10 and TNFalpha and increases survival among animals with lipopolysaccharide (LPS)-induced sepsis, even after a laparotomy. We demonstrated previously that the effect of CO(2) is not from changes in systemic pH, although the peritoneum is locally acidotic during abdominal insufflation with CO(2) even when systemic pH is corrected. We hypothesized that acidification of the peritoneum via means other than CO(2) insufflation would produce alterations in the inflammatory response similar to those associated with CO(2) pneumoperitoneum.

METHODS

In total, 42 rats were randomized into 7 groups (n = 6): 1) LPS only, 2) anesthesia control, 3) helium pneumoperitoneum, 4) CO(2) pneumoperitoneum, 5) buffered mild acid lavage, 6) buffered strong acid lavage, and 7) buffered strong acid lavage + helium pneumoperitoneum. Animals received anesthesia with vaporized isoflurane (except the LPS-only group) and their respective abdominal treatment (pneumoperitoneum and/or lavage) for 30 min followed immediately by stimulation with systemic LPS (1 mg/kg, IV). Blood was harvested via cardiac puncture 60 min after LPS injection, and serum levels of IL-10 and TNFalpha levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Mean peritoneal pH decreased (P < .05) after CO(2) pneumoperitoneum, buffered strong acid lavage, and buffered strong acid lavage + helium pneumoperitoneum, and it decreased (P = .1) after helium pneumoperitoneum alone and buffered mild acid lavage. IL-10 levels were increased (P < .01), and TNFalpha levels decreased (P < .001) among animals with acidic peritoneal cavities compared with animals with pH-normal peritoneal cavities. Decreasing peritoneal pH correlated with both increasing IL-10 levels (r = -.465, P < .01) and decreasing TNFalpha levels (r = 0.448, P < .01). Among animals with peritoneal acidosis, there were no differences in levels of IL-10 or TNFalpha regardless of insufflation status (P > .05 for both cytokines).

CONCLUSIONS

Acidification of the peritoneal cavity whether by abdominal insufflation or by peritoneal acid lavage increases serum IL-10 and decreases serum TNFalpha levels in response to systemic LPS challenge. The degree of peritoneal acidification correlates with the degree of inflammatory response reduction. These results support the hypothesis that pneumoperitoneum-mediated attenuation of the inflammatory response after laparoscopic surgery occurs via a mechanism of peritoneal cell acidification.

Endoscopic free electron laser technique development for minimally invasive optic nerve sheath fenestration

PURPOSE

This study proposed to develop a technique for efficiently accessing the posterior orbital space using endoscopy and attempted application of free electron laser (FEL) energy, biopsy forceps, electrocautery, and CO(2) insufflation to posterior orbital tissues.

METHODS

Through an inferior transconjunctival incision, access to the posterior orbital space was attempted in 14 eyes of 7 non-survival pigs. FEL energy (6.1 microm, 30 Hz, delivered via 250 microm hollow-glass waveguide), biopsy forceps, and monopolar electrocautery application were endoscopically attempted in the posterior orbit. CO(2) gas insufflation effects were assessed by analyzing arterial blood gases at 30-minute intervals for 1.5 hours.

RESULTS

The posterior orbit was accessed in 13 of 14 eyes, the optic nerve was encountered, and FEL energy was applied in 8 of 14 eyes. Use of biopsy forceps and electrocautery were successful. Although ANOVA results for arterial blood gas changes were not statistically significant, visibility was adequate without CO(2) insufflation.

CONCLUSIONS

The posterior orbit was endoscopically accessed and the optic nerve was exposed and successfully treated with FEL energy. CO(2) insufflation did not alter blood gases, but did not further enhance visibility in this study.

Physiologic changes during helium insufflation in high-risk patients during laparoscopic renal procedures

OBJECTIVES

To assess the efficacy and safety of helium as an insufflant for transabdominal laparoscopic renal surgery.

METHODS

The charts of all patients undergoing laparoscopic renal surgery with helium insufflation by a single physician between May 2003 and April 2006 were reviewed. Ventilatory parameters and postoperative recovery were reviewed.

RESULTS

Ten patients underwent laparoscopic renal surgery with helium. These patients had a mean age of 64 years and suffered from a variety of comorbid conditions, including chronic obstructive pulmonary disease (5), congestive heart failure (1), chronic hypoxia from an intrapulmonary shunt (1), malignant hyperthermia (1), and chronic hypoxia from multiple pulmonary infarcts (1). All patients tolerated helium pneumoperitoneum, with mean O2 saturation of 98.6% +/- 0.6%, end-tidal CO2 31.4 +/- 1.7 mm Hg, respiratory rate 9.3 +/- 0.7 breaths per minute, tidal volumes 598.2 +/- 38.0 mL, and peak airway pressures 26.0 +/- 1.2 cm H2O. One patient developed an end-tidal CO2 of greater than 45 mm Hg. Mean operative time was 146.8 +/- 59 minutes, and estimated blood loss was 280.1 +/- 334 mL. Postoperatively 3 patients required continued maintenance of the endotracheal tube, although none required intubation longer than 22 hours. Five patients had critical care monitoring (1.7 +/- 2.9 days on average).

CONCLUSIONS

Helium can be used safely as an insufflant during laparoscopic renal surgery. Patients who may benefit are those with potential difficulty in clearing CO2 gas from their bloodstream or those who rely on sensitive monitoring of end-tidal CO2 to manage comorbid pathology.

Peritoneal and systemic pH during pneumoperitoneum with CO2 and helium in a pig model

BACKGROUND

Local peritoneal effects of laparoscopic gases might be important in peritoneal biology during and after laparoscopic surgery. The most commonly used gas, CO(2), is known to be well tolerated, but also causes changes in acid-base balance. Helium is an alternative gas for laparoscopy. Although safe, it is not widely used. In this study a method for monitoring peritoneal pH during laparoscopy was evaluated and peritoneal pH during CO(2) and helium pneumoperitoneum was studied as well as its systemic reflection in arterial pH.

METHODS

For these experiments 20 pigs were used, with ten exposed to pneumoperitoneum with CO(2), and ten to helium. Peritoneal and sub-peritoneal pH were continuously measured before and during gas insufflation, during a 30-minute period with a pneumoperitoneum and during a 30-minute recovery period. Arterial blood-gases were collected immediately before gas insufflation, at its completion, at 30 minutes of pneumoperitoneum and after the recovery period.

RESULTS

Peritoneal pH before gas insufflation was in all animals 7.4. An immediate local drop in pH (6.6) occurred in the peritoneum with CO(2) insufflation. During pneumoperitoneum pH declined further, stabilising at 6.4, but was restored after the recovery period (7.3). With helium, tissue pH increased slightly (7.5) during insufflation, followed by a continuous decrease during pneumoperitoneum and recovery, reaching 7.2. Systemic pH decreased significantly with CO(2) insufflation, and increased slightly during helium insufflation. Systemic pH showed co-variation with intra-peritoneal pH at the the end of insufflation and after 30 minutes of pneumoperitoneum.

CONCLUSIONS

Insufflation of CO(2) into the peritoneal cavity seemed to result in an immediate decrease in peritoneal pH, a response that might influence biological events. This peritoneal effect also seems to influence systemic acid-base balance, probably due to trans-peritoneal absorption.

Pleural macrophages are the dominant cell population in the thoracic cavity with an inflammatory cytokine profile similar to peritoneal macrophages

Numerous human macrophage (mphi) subpopulations with different behavior have been identified in adults. It is well known that peritoneal mphi are activated by abdominal surgery and subsequently contribute to a systemic inflammatory response that leads to immune suppression, increased morbidity and mortality. Information on the role of pleural mphi in adults is scarce and information on their role in children is lacking. We investigated the behavior of pleural versus peritoneal mphi in children and adolescents. As a first step, we compared the cellular composition of the pleural and peritoneal surface in children and adolescents. Pleural and peritoneal lavages were performed in 21 patients undergoing non-contaminated laparoscopic and thoracoscopic surgical procedures. We observed a significantly higher percentage of mphi in the pleural compared to the peritoneal cavity with less lymphocytes, a small amount of polymorphonuclear cells (PMNs) and other cells. To further study the mphi inflammatory response, we measured the spontaneous and LPS triggered cytokine release of isolated pleural versus peritoneal mphi (IL-1beta, IL-6, and IL-10). The pattern of cytokine release was similar in both, pleural and peritoneal mphi. Directly after lavage, they showed a strong activation, with no difference between stimulated and non-stimulated cells. After 24 h resting, mphi of both compartments reacted to LPS with a similar significant increase in the cytokine release. In conclusion, our results demonstrate that pleural mphi represent the dominant cell population in the pleural cavity of the young. They show a similar inflammatory response as peritoneal mphi and should be considered to play a major role in the local inflammatory response to thoracic surgery.

Local and systemic impact of pneumoperitoneum on prepuberal rats

Pneumoperitoneum (PN) and the gas used to insufflate the abdominal cavity during laparoscopy seem to be responsible for local and systemic modifications. The aim of this study was to verify the effects of intra-abdominal carbon dioxide (CO(2)) and air insufflation on the peritoneum, as well as the cortico-surrenal response in prepuberal rats. Sixty prepuberal rats were divided into three groups: in the first (S, n = 36), PN was induced with CO(2), whereas in the second (A, n = 14), it was induced with filtered room air; in both conditions, insufflation lasted 30 min at a pressure of 10-12 mmHg. The third group (C, n = 10), underwent general anesthesia only. Two hours after inducing anaesthesia, 12 rats in group S, 6 in group A and 6 in group C were killed and the remaining, after 24 h; specimens of the visceral and the parietal peritoneum were obtained for histological examination, blood sample was taken for cortisol and DHEA-S assays at the different study periods. At the histological examination performed 2 h later, the groups S and A presented inflammatory cell infiltrate in the parietal and visceral peritoneum; this finding was even more marked in group A, which presented also congestion, hemorrhage and disruption of the cell line. Twenty-four hours after the experiment, the peritoneum of the two insufflated groups presented chronic infiltrate and reactive mesothelial cells with congestion, which was more evident in group A, but totally absent in group C. Cortisol levels were significantly higher in groups S and A (2.15:1 ratio) killed 2 h later compared to those killed 24 h later and to the control group. DHEA-S levels were not significantly different between the groups. Our results demonstrate that the chemical, physical and molecular impact of CO(2) on the peritoneum causes inflammation and tissue damage, this was even more evident 24 h after our experiment and in the air insufflated group. PN induced a significant variation in blood cortisol levels at 2 h. The CO(2) insufflation should be limited in patients with pre-existing peritoneal damage.

Acidification during carbon dioxide pneumoperitoneum is restricted to the gas-exposed peritoneal surface: effects of pressure, gas flow, and additional intraperitoneal fluids

BACKGROUND

There are varying data regarding the degree and extent of abdominal acidification during laparoscopy. The aim of this study was to determine the extent of peritoneal acidification during carbon dioxide insufflation and the effects of different pressures, insufflation rates, and free intraperitoneal fluids.

MATERIALS AND METHODS

Sixteen male Sprague-Dawley rats weighing 250-300 g were anesthetized and a two-point pH probe was inserted in the abdominal cavity. After closure of the abdominal wall, each group of 4 rats was subjected to one of four insufflation regimens: low pressure (2 mm Hg, no leakage); high pressure (10 mm Hg, no leakage); leakage (2 mm Hg, leakage 0.5 mL/min); and fluid (2 mm Hg, 10 mL intraperitoneal 0.9% NaCl). During insufflation peritoneal pH was continuously measured.

RESULTS

Carbon dioxide insufflation significantly decreased the peritoneal pH to <7.0 only in areas exposed to the insufflation gas. Neither changes in pressure nor insufflation rate had major effects on the peritoneal pH. The addition of 10 mL normal saline into the abdominal cavity significantly enhanced the pH change during insufflation. conclusion: Acidification associated with carbon dioxide pneumoperitoneum is limited to the area of inspection and manipulation. The increased acidification following injection of normal saline could offer a useful mechanism to alter the inflammatory response.

Gas-related impact of pneumoperitoneum on systemic wound healing

INTRODUCTION

The aim of the present study was to investigate the gas-dependent effects of pneumoperitoneum on wound healing distant from the abdomen.

MATERIALS AND METHODS

Dorsal skin incisions were performed in 54 male Sprague-Dawley rats. A CO(2) or a helium pneumoperitoneum of 3 mmHg was maintained before, with an overall duration of 30 min (each n = 18). Rats in the control group received laparotomy only (n = 18). Animals were killed after 5 and 10 days. The infiltration of macrophages (CD 68), expression of matrix metalloproteinase 13 (MMP-13) and collagen I/III ratios were analysed in the dorsal skin wounds.

RESULTS

Both after 5 and 10 days, infiltration of macrophages and expression of MMP-13 were greatest after helium pneumoperitoneum. After 5 days, collagen I/III ratio was significantly increased in the helium group. After 10 days, collagen I/III ratio was lowest in the CO(2) group.

CONCLUSION

Our results suggest beneficial effects on systemic wound healing for helium pneumoperitoneum as compared to CO(2).

Abdominal emergencies: diagnostic and therapeutic laparoscopy

BACKGROUND

Laparoscopy has been practiced in the management of emergencies resulting from inflammatory conditions, lumenal obstruction, perforation, vascular occlusion, and trauma. This article identifies and discusses controversial areas in the field, in particular surrounding the efficacy, cost effectiveness, and perceived advantages of laparoscopy in the evaluation and treatment of patients with acute abdominal conditions.

MATERIALS AND METHODS

Review and commentary on pertinent articles in the English language literature are presented.

RESULTS

Prospective randomized trials have been reported in the treatment of some disorders, but a lack of recommendations that are evidence-based has hindered more widespread usage of laparoscopy in an emergency setting. In addition, concerns have been raised that the creation of capnoperitoneum in the patient with established peritonitis may be detrimental with respect to potentiation of bacteremia and severe sepsis, and experimental studies have yielded conflicting data in this regard.

CONCLUSION

As such issues are resolved, utilization of laparoscopy is likely to increase substantially as expertise is acquired. A minimal-access approach carries less morbidity and may offer other practical advantages in terms of surgical technique and application. When surgical intervention is appropriate, laparoscopy is now preferred for acute biliary disease. Female patients of reproductive age with acute appendicitis may benefit, particularly if there is preoperative diagnostic uncertainty. Selected cases of intestinal obstruction and visceral perforation presenting soon after symptom onset and in whom shock is absent may also be amenable to laparoscopic repair. Its use in the treatment of most trauma patients and patients with generalized peritonitis or hemodynamic instability is not recommended at present.

Effect of acidosis on expression of mesothelial cell plasminogen activator inhibitor type-1

BACKGROUND

Abdominal mesothelial cells are exposed to carbon dioxide during laparoscopy. Previous data indicate that carbon dioxide increases release and expression of plasminogen activator inhibitor type-1 (PAI-1) and induces acidification.

METHODS

To assess the impact resulting from a range of pH, human mesothelial cells were exposed to culturing media balanced to pH levels of 6.0 to 8.0 for 90 min. Samples from cell media were withdrawn at several time points. Concentrations of PAI-1 and PAI-1 activity were measured using enzyme-linked immunoassay techniques. To focus on the effect of clinically relevant pH, cells were subjected to pH 6.4 and 7.4. Samples were withdrawn for PAI-1 assessments and for PAI-1 mRNA analyses.

RESULTS

During exposure to various levels of pH, PAI-1 secretion and activity were variable. However, 5 h after exposure, greater concentration and activity of PAI-1 were observed in acidified cultures. More PAI-1 mRNA was isolated after exposure of cells to a pH of 6.4, apparently indicating transcriptional regulation.

CONCLUSIONS

Mesothelial cells seem to respond to acidification by an increased release and production of PAI-1 in vitro.

Carbon dioxide differentially affects the cytokine release of macrophage subpopulations exclusively via alteration of extracellular pH

BACKGROUND

The improved outcome after endoscopic surgery has been attributed to less surgical trauma. However, the underlying mechanisms are not fully understood, and direct effects of CO2 used for pneumoperitoneum, cellular acidification, and/or the lack of air contamination have been postulated to additionally modulate immune functions during endoscopic surgery. We investigated the effects of CO2 incubation, extracellular acidification, and air contamination on the inflammatory response of two distinct macrophage populations.

METHODS

R2 and NR 8383 rat macrophage cell lines were used. Interleukin-6 (IL-6) and nitric oxide after lipopolysaccharide (LPS) stimulation were determined in these sets of experiments: incubation in 100% CO2, 5% CO2, and room air for 2h; incubation at pH 7.4, 6.5, and 5.5 for 2 h in 5% CO2; and incubation in 100% CO2, 5% CO2 and room air in fixed pH 6.3. The extracellular pH was monitored during incubation. We determined the alteration of intracellular pH in cells subjected to extracellular acidification by fluorescence microscopy.

RESULTS

Extracellular pH decreased to 6.3 during 100% CO2 incubation. IL-6 release was reduced after CO2 incubation in NR 8383 cells and increased in R2 cells (p < 0.05). It was not altered by air incubation. Decreasing the extracellular pH to 6.5 mimicked the effects of CO2 and a decrease to 5.5 suppressed IL-6 release in both cell lines. In fixed pH at 6.3, CO2 and air incubation had no effect. CO2 and pH had no impact on nitric oxide release and vitality. Intracellular pH decreased with extracellular acidification without significant difference between the two cell lines.

CONCLUSIONS

A decrease in extracellular pH during incubation in CO2 differentially affects IL-6 release in macrophage subpopulations. This may explain contradictory results in the literature. Moreover, we demonstrated that air contamination does not affect macrophage cytokine release. The decrease in extracellular pH is the primary underlying mechanism of the alteration of macrophage cytokine release after CO2 incubation, and it appears that the ability to maintain intracellular pH is not determined by the effects of CO2 or extracellular acidification.

[Immediate peritoneal response to contamination during laparoscopic surgery in an experimental mouse model]

INTRODUCTION

Several studies have shown that laparoscopic surgery (LS) minimizes surgical trauma and preserves immune response. Another advantage is the lower incidence of infectious complications. However, several in vitro studies have shown that an atmosphere with CO2 affects macrophage physiology, which would affect the response to peritoneal contamination. This observation is controversial, given the experimental evidence of a better conserved response to peritoneal contamination. The aim of the present study was to investigate the immediate response of the peritoneum to contamination in an atmosphere with CO2.

MATERIAL AND METHOD

A total of 192 CD-1 rats were distributed into three groups: group I, LP, n= 64, (laparotomy); group II, LC-CO2, n= 64, (laparoscopy-CO2), group III, LC-T, n= 64, (laparoscopy-traction). The rats were randomized to receive 1 ml of a suspension of Escherichia coli (1x10(4) CFU/ml) (contamination [C]) or saline serum (no contamination [NC]). Peritoneal fluid was obtained at 1.5, 3, 6, and 12 h after surgery. Monocyte chemotactic protein-1 (MCP-1), interleukin (IL)-6 and prostaglandin.E2 (PGE2) were determined.

RESULTS

MCP-1 levels were significantly higher and increased earlier in group II (LC-CO2-NC) than in group I (LP-NC) (p< .007). Simultaneously, the increase in the traction group was significantly higher (p< .002) than after laparotomy, without differences with respect to group II (LC-CO2-NC). When contamination was added, there was a significant increase in the three groups (p< .5). The modifications in MCP-1 in the LP-C group were statistically significantly greater and appeared earlier than those in the traction groups, LC-T-C (p< .002) and LC-CO2-C (p< .02). Interleukin 6: the three models showed a significant increase, which appeared later in the LP-NC group. Simultaneously, the increase in IL-6 appeared earlier and was significantly greater in the LC-T-NC group than in the LP group (p< .003), with no differences between the LC-CO2-NC and LC-T-NC groups. There was a significant difference between contaminated and uncontaminated groups in the LC-CO2 model. The traction model (LC-T-C group) showed a greater increase than the LP-C and LC-CO2-C groups (p< .001). PGE2: a significant increase was observed in the three models without contamination. However, when contamination was added, no differences were observed.

CONCLUSION

Pneumoperitoneum with CO2 provokes a peritoneal response that is qualitatively different from open surgery and modifies the response to contamination with a greater increase in MCP-1 and IL-6.

Immediate peritoneal response to bacterial contamination during laparoscopic surgery

BACKGROUND

Several studies have shown that laparoscopic surgery (LS) minimizes surgical trauma and the immune function is better preserved. Another major advantage of LS is the lower incidence of septic complications. However, several in vitro studies have shown that CO(2) severely impairs macrophage physiology. In theory, this would reduce the ability to respond to peritoneal contamination. However, there is some controversy in view of the evidence of a better preserved peritoneal response to sepsis. This study analyzed the early response of the peritoneum to contamination in a CO(2) ambience.

METHODS

A total of 192 CD-1 mice were distributed in three groups: group 1, laparotomy (LAP, n = 64); group 2, CO(2) laparoscopy (CO(2)-LC, n = 64); and group 3, wall lift laparoscopy (WL-LC, n = 64). Mice in each group were randomized to receive 1 ml of Escherichia coli suspension (1 x 10(4) colony-forming units/ml) or saline. Peritoneal fluid was obtained at 1.5, 3, 6, and 12 h after surgery. Monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), and prostaglandin E(2) (PGE(2)) were measured.

RESULTS

MCP-1 levels were significantly greater and higher earlier in group 2 (CO(2)-LC) than in group 1 (LAP) (p < 0.007). Simultaneously, the increment in the traction group (WL-LC, group 3) was significantly higher (p < 0.002) than after laparotomy, with no differences in group 2 (CO(2)-LC). When a contamination was added to the laparotomy subgroup, there was a significant increase compared to the group without contamination (p < 0.5). MCP-1 modifications after contamination in the LAP group were statistically significant and appeared later than in the WL-LC (p < 0.002) and CO(2)-LC groups (p < 0.02). For IL-6, the three models presented a significant increase in the noncontaminated groups. This occurred significantly later in the LAP group. Simultaneously, the increase in IL-6 occurred earlier and was significantly higher in the WL-LC group compared to the LAP group (p < 0.003), without differences between CO(2)-LC and wall lift groups. Significant differences between contaminated and noncontaminated subgroups were only observed in the LC-CO(2) groups. When contaminated, the traction model sustained a higher and earlier rise in IL-6 levels compared to the LAP and LC-CO(2) groups (p < 0.001). For PGE(2), The three models showed a significant increase in PGE(2) levels in the noncontaminated groups. However, there were no significant differences between them. In the contaminated groups, there was no statistical difference between the groups.

CONCLUSION

Despite a transient impairment of the immediate peritoneal response to a septic challenge, the degree of injury with LS is lower than that with open surgery, and abdominal infection can therefore be better controlled.

Urological laparoscopy: basic physiological considerations and immunological consequences

PURPOSE

The applications of laparoscopy to urological surgery continue to grow at a steady pace. A complete understanding of the physiological and immunological changes associated with pneumoperitoneum is required. We reviewed the physiology of laparoscopy with regard to the major organ systems and summarize the effects of pneumoperitoneum on immune function.

MATERIALS AND METHODS

Articles published in the scientific literature from 1990 to 2004 with relevance to laparoscopic physiology and the immune response to pneumoperitoneum were reviewed using PubMed.

RESULTS

Pneumoperitoneum induces predictable pulmonary and renal responses. The cardiovascular and hemodynamic responses are phasic and dynamic in nature, and only generalizations regarding cardiac function can be made. Renal parenchymal and venous compression during pneumoperitoneum are the etiology of oliguria during laparoscopy. The effects are reversible and cause no adverse effects on renal function. There is a general trend toward systemic immune preservation and peritoneal immune depression during insufflation based laparoscopy. Attenuated peritoneal immunity has been demonstrated most consistently by altered macrophage function.

CONCLUSIONS

Physiological changes incurred as a result of pneumoperitoneum have minimal adverse effects in healthy individuals undergoing laparoscopic surgery. Interest has grown in the impaired peritoneal immune response to CO2 pneumoperitoneum. Altered intraperitoneal immunity may represent a new avenue for the development of adjuvant therapies for minimally invasive treatments of urological malignancies and for the prevention of port site metastasis. Further elucidation and investigation into the immunological responses to pneumoperitoneum during urological laparoscopic procedures is called for.

Pneumoperitoneum and peritoneal surface changes: a review

BACKGROUND

Recent evidence suggests that the use of carbon dioxide to create a pneumoperitoneum during laparoscopy can lead to adverse structural, metabolic, and immune derangements within the peritoneal cavity, and that these can be dependent on the specific insufflation gas used. These changes include structural alterations in the mesothelial lining, pH disturbances, and alterations in peritoneal macrophage responsiveness. This contrasts with an apparent systemic benefit associated with laparoscopic, as compared with open, surgery.

METHODS

Recently published clinical and experimental studies related to the effect of pneumoperitoneum on the peritoneal surface are reviewed, and their relevance is discussed.

RESULTS

Structural changes in the peritoneal mesothelial surface layer such as widening of the intercellular junctions can be demonstrated with electron microscopy. Acidification of the peritoneum in response to carbon dioxide insufflation occurs not only at the peritoneal surface, but also in the underlying connective tissue, resulting in disturbances in the electrical surface charge and the release of various immune mediators such as endotoxin. Pneumoperitoneum also affects the local peritoneal immune environment resulting in alterations in cytokine production and phagocytic function, as well as diminished antitumor cell cytotoxicity.

CONCLUSIONS

Ultrastructural, metabolic, and immune alterations are observed at the peritoneal surface in response to a pneumoperitoneum. Experimental evidence suggests that these changes are carbon dioxide-specific effects. The consequences of these alterations to the local peritoneal environment are not well understood, but they may facilitate tumor implantation within the peritoneal cavity and adversely affect the ability to clear intraperitoneal infections. Further investigation into this area is warranted.

Efeitos do pneumoperitônio com ar e CO2 na gasometria de suínos

OBJETIVO: O pneumoperitônio produz várias alterações na fisiologia humana. Algumas destas alterações, como hipercapnia e acidose, dependem ou são agravadas com o uso de CO2, tendo maior repercussão em pacientes com problema cardio-respiratório. A necessidade de uma melhor alternativa para insuflação da cavidade; a observação de que as cirurgias abertas, assim como as laparoscópicas com suspensão mecânica, são realizadas na presença de Ar ambiente; e a escassez de trabalhos testando o Ar em substituição ao CO2 para insuflação da cavidade, foram motivos para a realização deste trabalho. MÉTODOS: Vinte (0) suínos anestesiados foram submetidos a pneumoperitônio com 1 hora de duração. Os animais foram distribuídos em 4 grupos de 5 animais: Grupo A1 - Pneumoperitônio de Ar a 10 mmHg; Grupo A - Pneumoperitônio de Ar a 16 mmHg; Grupo B1 - Pneumoperitônio de CO2 a 10 mmHg; Grupo B - Pneumoperitônio de CO2 a 16 mmHg. O pneumoperitônio foi realizado pela técnica aberta com trocater de Hasson. Através de um cateter venoso central colhe-se amostra de sangue para exame de gasometria em 3 momentos. RESULTADOS: A análise da gasometria venosa não revelou alterações significativas entre os grupos em relação a PaO2 e a saturação do O2. Nos Grupos A1, A e B1 não foram observadas alterações no equilíbrio ácido-básico. No Grupo B após uma hora de pneumoperitônio houve nítida tendência a hipercapnia e acidose. CONCLUSÃO: O ar, com a técnica aberta de pneumoperitônio foi uma opção segura para insuflação de cavidade em procedimentos laparoscópicos diagnósticos de suínos.

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.