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

Cost-effectiveness of gasless laparoscopy as a means to increase provision of minimally invasive surgery for abdominal conditions in rural North-East India

Laparoscopic surgery, a minimally invasive technique to treat abdominal conditions, has been shown to produce equivalent safety and efficacy with quicker return to normal function compared to open surgery. As such, it is widely accepted as a cost-effective alternative to open surgery for many abdominal conditions. However, access to laparoscopic surgery in rural North-East India is limited, in part due to limited equipment, unreliable supplies of CO₂ gas, lack of surgical expertise and a shortage of anaesthetists. We evaluate the cost-effectiveness of gasless laparoscopy as a means to increase provision of minimally invasive surgery (MIS) for abdominal conditions in rural North-East India. A decision tree model was developed to compare costs, evaluated from a patient perspective, and health outcomes, disability adjusted life years (DALYs), associated with gasless laparoscopy, conventional laparoscopy or open abdominal surgery in rural North-East India. Results indicate that MIS (performed by conventional or gasless laparoscopy) is less costly and produces better outcomes, fewer DALYs, than open surgery. These results were consistent even when gasless laparoscopy was analysed using least favourable data from the literature. Scaling up provision of MIS through increased access to gasless laparoscopy would reduce the cost burden to patients and increase DALYs averted. Based on a sample of 12 facilities in the North-East region, if scale up was achieved so that all essential surgeries amenable to laparoscopic surgery were performed as such (using conventional or gasless laparoscopy), 64% of DALYS related to these surgeries could be averted, equating to an additional 454.8 DALYs averted in these facilities alone. The results indicate that gasless laparoscopy is likely to be a cost-effective alternative to open surgery for abdominal conditions in rural North-East India and provides a possible bridge to the adoption of full laparoscopic services.

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.

Clinical effectiveness of gasless laparoscopic surgery for abdominal conditions: systematic review and meta-analysis

BACKGROUND

In high-income countries, laparoscopic surgery is the preferred approach for many abdominal conditions. Conventional laparoscopy is a complex intervention that is challenging to adopt and implement in low resource settings. This systematic review and meta-analysis evaluate the clinical effectiveness of gasless laparoscopy compared to conventional laparoscopy with CO₂ pneumoperitoneum and open surgery for general surgery and gynaecological procedures.

METHODS

A search of the MEDLINE, EMBASE, Global Health, AJOL databases and Cochrane Library was performed from inception to January 2021. All randomised (RCTs) and comparative cohort (non-RCTs) studies comparing gasless laparoscopy with open surgery or conventional laparoscopy were included. The primary outcomes were mortality, conversion rates and intraoperative complications.

SECONDARY OUTCOMES

operative times and length of stay. The inverse variance random-effects model was used to synthesise data.

RESULTS

63 studies were included: 41 RCTs and 22 non-RCTs (3,620 patients). No procedure-related deaths were reported in the studies. For gasless vs conventional laparoscopy there was no difference in intraoperative complications for general RR 1.04 [CI 0.45-2.40] or gynaecological surgery RR 0.66 [0.14-3.13]. In the gasless laparoscopy group, the conversion rates for gynaecological surgery were high RR 11.72 [CI 2.26-60.87] when compared to conventional laparoscopy. For gasless vs open surgery, the operative times were longer for gasless surgery in general surgery RCT group MD (mean difference) 10 [CI 0.64, 19.36], but significantly shorter in the gynaecology RCT group MD - 18.74 [CI - 29.23, - 8.26]. For gasless laparoscopy vs open surgery non-RCT, the length of stay was shorter for gasless laparoscopy in general surgery MD - 3.94 [CI - 5.93, - 1.95] and gynaecology MD - 1.75 [CI - 2.64, - 0.86]. Overall GRADE assessment for RCTs and Non-RCTs was very low.

CONCLUSION

Gasless laparoscopy has advantages for selective general and gynaecological procedures and may have a vital role to play in low resource settings.

Does Helium Pneumoperitoneum Reduce the Hyperinflammatory Response in Septic Animals during Laparoscopy?

Background/Aim. An exacerbated reaction to peritoneal infection and attendant surgical procedures is characterized by an intense hyperinflammatory state, the magnitude of which is proportional to the severity of tissue injury. Laparoscopy generates lower levels of tissue damage compared with open surgery and should induce less pronounced immune responses. The aim of this study was to determine whether laparoscopy assisted by helium rather than carbon dioxide pneumoperitoneum would induce an attenuated inflammatory state in septic animals. Materials and Methods. Thirty-two Wistar rats were divided randomly into four equal groups, two of which were submitted to carbon dioxide or helium pneumoperitoneum-assisted laparoscopic cecal ligation and puncture (CLP) induced sepsis and subsequent abdominal lavage. Two control groups were submitted to identical laparoscopic procedures with carbon dioxide or helium as insufflator gas but without CLP. After 24 hours, serum levels of tumor necrosis factor alpha (TNF-α), interleukins 1 and 6 (IL-1 and IL-6, respectively), and cortisol were determined.

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.

Partial amniotic carbon dioxide insufflation for fetal surgery

Partial amniotic carbon dioxide insufflation (PACI) involves insufflating the amniotic sac with carbon dioxide (CO₂ ) and, in some cases, draining some of the amniotic fluid. The creation of a gaseous intra-amniotic compartment improves visualization, even in the presence of limited bleeding, and creates the work space required for complex fetoscopic procedures. Clinically, PACI is mostly used to perform fetoscopic myelomeningocele (MMC) repair, enabling a minimally invasive alternative to open fetal surgery. However, evidence of the fetal safety of PACI is limited. Previous animal experiments in sheep demonstrate that PACI induces fetal hypercapnia and acidosis with largely unknown short and longer term implications. In this review, we examine the literature for the physiological effects of intrauterine insufflation pressure, duration, humidity, and the role of maternal hyperventilation on fetal physiology and well-being.

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.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery

BACKGROUND

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). Many other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum.

OBJECTIVES

To assess the safety, benefits, and harms of different gases for establishing pneumoperitoneum in patients undergoing laparoscopic abdominal surgery.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and Chinese Biomedical Literature Database (CBM) until September 2012.

SELECTION CRITERIA

We only included randomized controlled trials comparing different gases for establishing pneumoperitoneum in patients undergoing laparoscopic abdominal 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 the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) or standardized mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Carbon dioxide pneumoperitoneum versus nitrous oxide pneumoperitoneum Three trials randomized 196 participants (the majority with low anaesthetic risk) to carbon dioxide pneumoperitoneum (n =96) or nitrous oxide pneumoperitoneum (n =100). All of the trials were of high risk of bias. Two trials (n=143) showed lower pain scores in nitrous oxide pneumoperitoneum at various time points on the first post-operative day. One trial (n=53) showed no difference in the pain scores between the groups. There were no significant differences in cardiopulmonary complications, surgical morbidity, or cardiopulmonary changes between the groups. There were no serious adverse events related to either carbon dioxide or nitrous oxide pneumoperitoneum. Carbon dioxide pneumoperitoneum versus helium pneumoperitoneum Four trials randomized 144 participants (the majority with low anaesthetic risk) to carbon dioxide pneumoperitoneum (n =75) or helium pneumoperitoneum (n =69). All of the trials were of high risk of bias. Fewer cardiopulmonary changes were observed with helium pneumoperitoneum than carbon dioxide pneumoperitoneum. There were no significant differences in cardiopulmonary complications, surgical morbidity, or pain scores. There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum. Carbon dioxide pneumoperitoneum versus any other gas pneumoperitoneum There were no randomized controlled trials comparing carbon dioxide pneumoperitoneum to any other gas pneumoperitoneum.

AUTHORS' CONCLUSIONS

1. Nitrous oxide pneumoperitoneum during laparoscopic abdominal surgery appears to decrease post-operative pain in patients with low anaesthetic risk.2. Helium pneumoperitoneum decreases the cardiopulmonary changes associated with laparoscopic abdominal surgery. However, this did not translate into any clinical benefit over carbon dioxide pneumoperitoneum in patients with low anaesthetic risk.3. The safety of nitrous oxide and helium pneumoperitoneum has yet to be established. More randomized controlled trials on this topic are needed. Future trials should include more patients with high anaesthetic risk. Furthermore, such trials need to use adequate methods to reduce the risk of bias.

Systemic inflammatory response after single-incision laparoscopic surgery versus standard laparoscopic approach

PURPOSE

The extent of surgical trauma is reflected by systemic inflammatory response (SIR). The aim of this study was to assess SIR after single-incision laparoscopic surgery (SILS) versus the standard laparoscopic approach.

MATERIALS AND METHODS

Twenty pigs were assigned into 4 groups: SILS (group SILS), laparoscopy using 4 trocars (group LAPSC), pneumoperitoneum (group PNE), or a sham-operation (group Sham) group. Blood samples were taken at 0, 1, 3, 6, 24, and 48 hours and 1 week postoperation to measure tumor necrosis factor-α, interleukin (IL)-6, IL-18, and C-reactive protein serum levels.

RESULTS

No significant changes were noted among groups for each time point studied regarding tumor necrosis factor-α, IL-6, and IL-18. C-reactive protein levels were significantly lower (P<0.05) in group PNE compared with the other groups at 24 hours, 48 hours, and 1 week.

CONCLUSIONS

There is no difference in SIR after SILS versus the standard laparoscopic approach.

Tumor necrosis factor expression is ameliorated after exposure to an acidic environment

BACKGROUND

It has been well established that laparoscopic surgery presents several clinical benefits, including reduced pain and a shorter hospital stay. These effects have been associated with a decrease in the inflammatory response. Previous studies have demonstrated that reduced inflammation after laparoscopic surgery is the product of carbon dioxide insufflation, which decreases peritoneal pH. The objective of this study was to investigate the cellular and molecular mechanisms responsible for the reduced response after exposure to acidic environments.

MATERIALS AND METHODS

A murine macrophage line (J744) was incubated in culture medium at pH 6.0 or pH 7.4 for 3 h at 37°C. Then, cells were stimulated with lipopolysaccharide (LPS) at pH 7.4, the expression of TNF-α (qRT-PCR or enzyme-linked immunosorbent assay (ELISA) and intracellular pH were measured. In addition, CD14 and Toll-like receptor 4 expression and NF-κB nuclear translocation were analyzed.

RESULTS

A significant decrease in LPS-induced TNF-α expression levels was observed in cells pre-incubated at pH 6.0 in comparison with cells at neutral pH conditions. This decrease in TNF-α levels was not associated with a reduction in cell surface expression of CD14 and Toll-like receptor 4. Exposure to an extracellular acidic environment resulted in a reduction of IκB phosphorylation and NF-κB nuclear translocation, secondary to a significant drop in cytosolic pH.

CONCLUSIONS

These observations provide a potential mechanism for the reduced expression of TNF-α after exposure to low extracellular pH, which may be related to acidification after CO(2) insufflation during laparoscopic surgery. In addition, extracellular acidic pH environments could emerge as an important regulator of macrophage function.

Carbondioxide pneumoperitoneum prevents postoperative adhesion formation in a rat cecal abrasion model

PURPOSE

We aimed to investigate the role of the carbon-dioxide (CO(2)) pneumoperitoneum on the prevention of postoperative adhesion formation.

METHODS

Thirty adult male Sprague-Dawley rats (250-350 g) were used for this study. The rats were randomly divided into three groups; in the sham group (n = 10) only, laparotomy was made, in group 2 (n = 10), a pneumoperitoneum was applied for a half-hour duration, followed by laparatomy, and in group 3 (n = 10), pneumoperitoenum time was 2 hours and after a pneumoperitoneum laparotomy was made. A cecal abrasion model was studied for making an adhesion formation. On day 14, all rats were sacrificed and adhesions were scored. Tissue samples from adhesions and peritonea and the cecum wall were examined, both pathologically and biochemically, for tissue hydroxyproline content.

RESULTS

There was a statistically significant difference between the control and pneumoperitoneum groups, regarding adhesion numbers and grades (P < 0.001). Cecal tissue hydroxypyroline content level was lower in group 1, and statistically significant differences were observed between groups 1, 2, and 3 regarding hydroxyproline content (P < 0.001). There was a statistically significant difference between the control and pneumoperitoneum groups regarding inflammation (P = 0.002).

CONCLUSIONS

Pretreatment with the CO(2) pneumoperitoneum had a prophylactic effect on postoperative adhesion formation in this study.

Laparoscopic surgery and the parasympathetic nervous system

BACKGROUND

Laparoscopic surgery preserves the immune system and has anti-inflammatory properties. CO2 pneumoperitoneum attenuates lipopolysaccharide (LPS)-induced cytokine production and increases survival. We tested the hypothesis that CO2 pneumoperitoneum mediates its immunomodulatory properties via stimulation of the cholinergic pathway.

METHODS

In the first experiment, rats (n = 68) received atropine 1 mg/kg or saline injection 10 min prior to LPS injection and were randomization into four 30-min treatment subgroups: LPS only control, anesthesia control, CO2 pneumoperitoneum, and helium pneumoperitoneum. In a second experiment, rats (n = 40) received atropine 2 mg/kg or saline 10 min prior to randomization into the same four subgroups described previously. In a third experiment, rats (n = 96) received atropine 2 mg/kg or saline 10 min prior to randomization into eight 30-min treatment subgroups followed by LPS injection: LPS only control; anesthesia control; and CO2 or helium pneumoperitoneum at 4, 8, and 12 mmHg. In a fourth experiment, rats (n = 58) were subjected to bilateral subdiaphragmatic truncal vagotomy or sham operation. Two weeks postoperatively, animals were randomized into four 30-min treatment subgroups followed by LPS injection: LPS only control, anesthesia control, CO2 pneumoperitoneum, and helium pneumoperitoneum. Blood samples were collected from all animals 1.5 h after LPS injection, and cytokine levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Serum tumor necrosis factor-alpha (TNF-alpha) levels were consistently suppressed among the saline-CO2 pneumoperitoneum groups compared to saline-LPS only control groups (p < 0.05 for all four experiments). All chemically vagotomized animals had significantly reduced TNF-alpha levels compared to their saline-treated counterparts (p < 0.05 for all), except among the CO2 pneumoperitoneum-treated animals. Increasing insufflation pressure with helium eliminated differences (p < 0.05) in TNF-alpha production between saline- and atropine-treated groups but had no effect among CO2 pneumoperitoneum-treated animals. Finally, vagotomy (whether chemical or surgical) independently decreased LPS-stimulated TNF-alpha production in all four experiments.

CONCLUSION

CO2 pneumoperitoneum modulates the immune system independent of the vagus nerve and the cholinergic pathway.

[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.

CO2 abdominal insufflation pretreatment increases survival after a lipopolysaccharide-contaminated laparotomy

Carbon dioxide (CO(2))-pneumoperitoneum is known to favorably modify the systemic immune response during laparoscopic surgery. The presented studies were designed to determine whether treating animals with CO(2) abdominal insufflation before undergoing a lipopolysaccharide (LPS)-contaminated laparotomy would serve as "shock prophylaxis" and thus improve survival and attenuate cytokine production. Rats were randomized into five groups: CO(2)-pneumoperitoneum, helium-pneumoperitoneum, anesthesia control, laparotomy/LPS control, and LPS only control. Animals in the first four groups all received a laparotomy and a lethal dose of LPS. Immediately preceding their laparotomy, animals in the pneumoperitoneum groups received a 30-minute pretreatment of abdominal insufflation with either CO(2) or helium. The anesthesia control group received a 30-minute pretreatment of isoflurane. Animal mortality was then recorded during the ensuing 72 hours. Subsequently, a similar protocol was repeated for measurements of cytokines. CO(2)-pneumoperitoneum increased survival at 48 hours compared with LPS control (P <.05), and decreased interleukin-6 plasma levels at 2 hours (P <.05). Abdominal insufflation with CO(2) before the performance of a laparotomy contaminated with endotoxin increases survival and attenuates interleukin-6. The beneficial immune-modulating effects of CO(2)-pneumoperitoneum endure after abdominal insufflation. CO(2)-pneumoperitoneum pretreatment may improve outcomes among patients undergoing gastrointestinal surgery who are at high risk for abdominal fecal contamination.

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.

Mini-laparotomy and full laparotomy, but not laparoscopy, alter hepatic macrophage populations in a rat model

BACKGROUND

Immune function is better preserved by laparoscopic versus conventional surgery. Numerous mediators of the systemic trauma response are synthesized and/or regulated by the liver. However, it has been stated that the advantages of laparoscopic surgery are no more obvious when conventional operations are performed via mini-laparotomy. We set out to compare the impact of laparoscopy and mini- and full laparotomy on the hepatic macrophage populations.

METHODS

Male Lewis rats were subjected to anesthesia alone (control), mini-laparotomy (1 cm), full laparotomy (7 cm), or laparoscopy for 60 min. Endpoints were the total protein in the peritoneal lavage fluid, hepatic ED-1 cells (recruited monocytes), hepatic ED-2 cells (Kupffer cells), the expression of OX-6 in the liver, and C-reactive protein (CRP) in plasma.

RESULTS

Protein in the peritoneal lavage fluid increased significantly after all interventions. Full laparotomy was accompanied by an enhancement in ED-1-positive monocytes in the liver parenchyma compared to all other groups (p < 0.001). Mini- and full laparotomy led to an increase in ED-2-positive Kupffer cells (p < 0.001). Laparoscopy did not affect the number of monocytes/macrophages. There was no significant alteration of OX-6 expression in either group. No change in the cellular composition in the periportal fields was observed. The CRP plasma levels did not significantly differ between groups.

CONCLUSIONS

Laparoscopy completely prevents hepatic macrophage populations from expansion and normal cell disposition is preserved. Laparotomy, irrespective of incision size, increases the number of Kupffer cells. Moreover, full laparotomy, but not mini-laparotomy or laparoscopy, causes an increase in hepatic monocyte recruitment. The regulating pathways after surgery differ from other immunologic challenges, such as sepsis, in which immunocompetent cells accumulate and are stimulated in the periportal fields.

Carbon dioxide pneumoperitoneum–mediated attenuation of the inflammatory response is independent of systemic acidosis

BACKGROUND

The purpose of this study was to determine if systemic acidosis induced by peritoneal absorption of carbon dioxide (CO2 ) during laparoscopy plays a role in CO2 pneumoperitoneum-mediated attenuation of the acute phase inflammatory response associated with perioperative sepsis. The influence of hepatic polymorphonuclear (PMN) leukocyte infiltration on this phenomenon was also investigated.

METHODS

Forty-five rats were randomized into 5 groups: anesthesia control, open cecal ligation and puncture (OCLP), laparoscopic cecal ligation and puncture using helium for insufflation (He LCLP), LCLP using CO2 with continued spontaneous ventilation (LCLP-SV), and LCLP using CO2 with intubation and positive pressure ventilation (LCLP-PPV).

RESULTS

After 30 minutes, arterial blood gas parameters remained normal in control, OCLP rats, and He LCLP rats, while CO2 LCLP-SV rats developed significant hypercarbic acidosis. This acidosis was corrected in CO2 LCLP-PPV rats ( P < .0001 vs CO2 LCLP-SV for both). Expression of the rat acute phase gene alpha 2 -macroglobulin was greater after OCLP and He LCLP than after either CO2 LCLP-SV or CO2 LCLP-PPV ( P < .0001 vs either CO2 OCLP-SV for both). However, levels of alpha 2 -macroglobulin were not significantly different between the acidotic (LCLP-SV) and normocarbic (LCLP-PPV) CO2 groups. Infiltration of the hepatic parenchyma by PMNs did not differ significantly between groups.

CONCLUSIONS

CO2 insufflation-induced systemic acidosis is not responsible for the reduction in the acute phase inflammatory response observed in laparoscopic animal models of sepsis. Hepatic PMN infiltration also does not appear to mediate this effect.

The effect of timing of pneumoperitoneum on the inflammatory response

BACKGROUND

We examined the effects of an identical period of pneumoperitoneum applied at three different time points after lipopolysaccharide (LPS) challenge. Two different insufflation gases were also compared.

METHODS

Male rats (n = 70) were injected intravenously with 1 mg/kg of LPS (time 0). The time relationship between a 1.5-h period of insufflation and initial LPS stimulation was the experimental variable. All rats were killed 6 h after injection. CO2 and helium insufflation were investigated. Ten control rats received LPS only. Serum interleukin-6 (IL-6) levels were determined by enzyme-linked immunosorbent assay (ELISA). Hepatic expression of alpha2-macroglobulin, beta-fibrinogen, and metallothionein were measured by Northern blot analysis. Statistical analysis was performed using one-way analysis of variance (ANOVA).

RESULTS

Expression of alpha2-macroglobulin mRNA was lower in CO2 groups compared to the control group (p < 0.05 at time 120 and 270). beta-Fibrinogen message was diminished in CO2 0 and 120 groups compared to control. Serum levels of IL-6 and expression of metallothionein mRNA did not show significant differences between groups.

CONCLUSIONS

These findings suggest that CO2 pneumoperitoneum downregulates the inflammatory response to LPS challenge. Start time of CO2 insufflation does not appear to alter hepatic expression of acute phase genes. The mechanism of alpha2-macroglobulin downregulation does not appear to be due to IL-6.

Surgical trauma: hyperinflammation versus immunosuppression?

BACKGROUND

Experimental and clinical studies have brought evidence that surgical trauma markedly affects the immune system, including both the specific and the non-specific immune response.

MATERIALS AND METHODS

This report reviews the present knowledge on the mechanisms of surgical trauma-induced immune dysfunction and outlines experimental and clinical approaches to find effective treatment strategies.

RESULTS

Major surgical trauma induces an early hyperinflammatory response, which is characterized by (1) pro-inflammatory tumour necrosis factor alpha (TNF), interleukin (IL)-1, and IL-6 cytokine release and (2) neutrophil activation and microvascular adherence, as well as (3) uncontrolled polymorphonuclear (PMN) and macrophage oxidative burst. The massive and continuous IL-6 release induces an acute phase response, but, more importantly, also accounts for the up-regulation of major anti-inflammatory mediators, such as prostaglandin (PG) E2, IL-10 and transforming growth factor (TGF)-ss. This results in surgical, trauma-induced, immunosuppression, as indicated by (1) monocyte deactivation, reflected by the lack of monocytic TNF- production upon lipopolysaccharide (LPS) stimulation, and (2) a shift of the Th1/Th2 ratio towards a Th2-dominated cytokine pattern. The imbalance between pro-inflammatory and anti-inflammatory cytokines and immuno-competent cells determines the phenotype of disease and should help the physician to compose the therapeutic strategy. In fact, recent clinical studies have shown that both the initial uncontrolled hyperinflammation and the continued cell-mediated immunosuppression represent primary targets to counteract post-surgery immune dysfunction. The balance between inflammatory and anti-inflammatory forces may be restored by interferon gamma (IFN-gamma) to counteract monocyte deactivation; the anti-inflammatory PGE2 may be inhibited by indomethacin to attenuate immunosuppression; or the initial hyperinflammation may be targeted by administration of anti-inflammatory substances, such as granulocyte colony-stimulating factor (G-CSF), hydoxyethyl starch, or pentoxifylline.

CONCLUSIONS

When drawing up the therapeutic regimen the physician should not consider hyperinflammation versus immunosuppression, but hyperinflammation and immunosuppression, aiming at restoring an appropriate mediator- and immune cell-associated balance.