Meta-analysis of the effect of warm humidified insufflation on pain after laparoscopy

Effectiveness of Dry Heat Versus Moist Heat Modalities on Pain Intensity and Wound Healing of Episiotomies Among Postnatal Women: A Systematic Review and Meta-Analysis

OBJECTIVES

Comparison of the effects of dry heat versus moist heat therapy modalities on the intensity of pain and wound healing of episiotomies among postnatal women.

DESIGN

A Systematic review and meta-analysis of controlled trials.

DATA SOURCES

Six databases searched for original articles using relevant keywords until September 10, 2023, without time or language restrictions.

REVIEW/ANALYSIS METHODS

All analyses employed Comprehensive Meta-Analysis (CMA) V.2. The measure of heterogeneity was computed using Cochran's Q-value. The I2 index was employed to quantitatively demonstrate heterogeneity. Statistical significance was reported for P-values <0.05 and I2>50%.

RESULTS

Four quasi-experimental and three randomized controlled trials (RCTs) studies with moderate-to-good quality evidence met inclusion criteria. On the third to fifth day after the intervention in the dry heat group, the amount of pain was significantly lower than in the group that used moist heat [MD (95% CI) =-1.395 (-2.374, -0.416), P=0.005]. The use of a hair dryer significantly reduced pain (P=0.029), but an infrared lamp did not significantly reduce pain compared to moist heat (P=0.064). As compared to the moist heat group, the women using dry heat experienced better wound healing to the extent of 2.002 units of the REEDA (Redness, Edema, Ecchymosis, Discharge, Approximation) scale, which was statistically significant [MD (95% CI) = -2.002 (-2.785, -1.219), P<0.001].

CONCLUSION

Compared to sitz baths, dry heat reduced pain and improved episiotomy site healing in postnatal women. Therefore, dry heat, especially hair dryers, is suggested as a non-pharmacological strategy inside maternity hospitals, but additional targeted, high-quality trials are needed.

Effect of Surgical Humidification on Inflammation and Peritoneal Trauma in Colorectal Cancer Surgery: A Randomized Controlled Trial

BACKGROUND

Pre-clinical studies indicate that dry-cold-carbon-dioxide (DC-CO2) insufflation leads to more peritoneal damage, inflammation and hypothermia compared with humidified-warm-CO₂ (HW-CO2). Peritoneum and core temperature in patients undergoing colorectal cancer (CRC) surgery were compared.

METHODS

Sixty-six patients were randomized into laparoscopic groups; those insufflated with DC-CO2 or HW-CO2. A separate group of nineteen patients undergoing laparotomy were randomised to conventional surgery or with the insertion of a device delivering HW-CO2. Temperatures were monitored and peritoneal biopsies and bloods were taken at the start of surgery, at 1 and 3 h. Further bloods were taken depending upon hospital length-of-stay (LOS). Peritoneal samples were subjected to scanning electron microscopy to evaluate mesothelial damage.

RESULTS

Laparoscopic cases experienced a temperature drop despite Bair-Hugger^TM use. HW-CO2 restored normothermia (≥ 36.5 °C) by 3 h, DC-CO2 did not. LOS was shorter for colon compared with rectal cancer cases and if insufflated with HW-CO2 compared with DC-CO2; 5.0 vs 7.2 days, colon and 11.6 vs 15.4 days rectum, respectively. Unexpectedly, one third of patients had pre-existing damage. Damage increased at 1 and 3 h to a greater extent in the DC-CO2 compared with the HW-CO2 laparoscopic cohort. C-reactive protein levels were higher in open than laparoscopic cases and lower in both matched HW-CO2 groups.

CONCLUSIONS

This prospective RCT is in accord with animal studies while highlighting pre-existing damage in some patients. Peritoneal mesothelium protection, reduced inflammation and restoration of core-body temperature data suggest benefit with the use of HW-CO2 in patients undergoing CRC surgery.

Perioperative hypothermia in open and laparoscopic colorectal surgery

BACKGROUND

The consequences of even mild inadvertent perioperative hypothermia (IPH) are significant. There is a perception laparoscopic abdominal surgery is less prone to cause hypothermia than open surgery. However, during laparoscopic surgery, the peritoneal cavity is insufflated with carbon dioxide, which has a greater evaporative capacity than ambient air. This study compared the intra-operative temperature profile of patients undergoing open and laparoscopic colorectal surgery to define the incidence and severity of hypothermia.

METHODS

All adult patients undergoing colorectal surgery between May 2005 and August 2013 were identified from an electronic database. Cases were categorized into laparoscopic and open cases. Hypothermic episodes were defined as a temperature less than 36°C lasting for more than two consecutive minutes. The incidence of hypothermic episodes, the total time under 36°C and the area under the curve (degree-minutes) were calculated.

RESULTS

A total of 1547 cases were analysed. The overall incidence of hypothermia was 67.0%. The incidence of cases with a hypothermic episode was greater in the laparoscopic group compared to the open group (71.23% versus 63.16%; chi-squared P-value 0.001). However, when other factors were considered, there was no significant difference in the relative risk of a hypothermic episode between types of surgery. There were significant differences in the severity of hypothermia.

CONCLUSION

Despite current measures to reduce the incidence, IPH remains a significant problem in colorectal surgery irrespective of the surgical approach. Further research is required to better characterize techniques that can reduce its incidence.

Warm and humidified insufflation gas during gynecologic laparoscopic surgery reduces postoperative pain in predisposed patients-a randomized, controlled multi-arm trial

BACKGROUND

Postoperative pain remains a common problem in gynecologic laparoscopy, especially in head zone-related regions, triggered by intra-abdominal pressure during capnoperitoneum. Humidified and prewarmed insufflation gas may ameliorate pain and be beneficial.

METHODS

This prospective randomized controlled parallel group multi-arm single-center study investigated the effects of temperature and humidity of insufflation gas on postoperative pain during gynecologic laparoscopy with a duration ≥ 60 min. Female participants (18-70 years) were blinded and randomly assigned-computer generated-to either insufflation with dry cold CO₂ with forced air warming blanket ("AIR"), humidified warm gas without forced air warming blanket ("HUMI"), or humidified warm gas with forced air warming blanket ("HUMI +"). We hypothesized that using humidified warm gas resulted in lower pain scores and less analgesic consumption. The primary endpoint postoperative pain was assessed for different pain localizations every 12 h during 7 days after surgery. Secondary endpoints were demand for painkillers and epidural anesthetics, length of stay in recovery room, and hospital stay. (Registration: ClinicalTrials.gov NCT02781194-completed).

RESULTS

150 participants were randomized. Compared to group "AIR" (n = 48), there was significantly less pain in group "HUMI +" (n = 48) in the recovery room (- 1.068; 95% CI - 2.08 to - 0.061), as well as significantly less ibuprofen use at day two (- 0.5871 g ± 0.258; p-value = 0.0471). Other variables did not change significantly. Stratification for presence of endometriosis or non-previous abdominal surgery in patient history revealed significantly less pain in both groups "HUMI" (n = 50) and "HUMI +" versus group "AIR." Related side effects were not noted.

CONCLUSION

In the overall population, the use of warm, humidified insufflation gas did not yield clinically relevant effects; however, in predisposed patients with endometriosis and who could otherwise expect high pain levels, warm and humidified gas may be beneficial.

Warm distension fluid reduces pain severity in office hysteroscopy: a randomized controlled trial

BACKGROUND

Abnormal uterine bleeding (AUB) affects approximately 14% to 25% of women of reproductive age. The most common use of office hysteroscopy is to evaluate pathologies related to AUB and reproductive health, but office hysteroscopy can also be used for the diagnosis and treatment of other intrauterine pathologies.

OBJECTIVE

Investigate the effects of the temperature of the distension fluid on pain severity in patients undergoing diagnostic office hysteroscopy due to AUB.

DESIGN

Randomized controlled clinical trial.

SETTING

Tertiary care center in Turkey.

PATIENTS AND METHODS

One hundred perimenopausal patients with AUB were randomly allocated according to the temperature of the distension fluid used in office hysteroscopy (37°C or 25°C). Pain intensity was assessed using a visual analog scale (VAS). Six VAS measurements were compared over the course of the hysteroscopy: pre-treatment (VAS-1), at vaginal entry (VAS-2), at the cervical ostium transition (VAS-3), while in the cavity (VAS-4), at the end of the procedure (VAS-5), and 30 minutes after the end of the procedure (VAS-6).

MAIN OUTCOME MEASURE

VAS SAMPLE SIZE: Fifty in each group enrolled, one drop out.

RESULTS

The VAS-3, VAS-4, and VAS-5 scores were significantly lower for patients in the warm fluid group than in the room temperature group (P<.05), whereas the VAS-1, VAS-2, and VAS-6 scores were similar in both groups.

CONCLUSION

The application of warm distension fluid in office hysteroscopy reduces pain severity compared with the application of an unheated fluid.

LIMITATIONS

The main limitations of the study were that a subgroup analysis could not be performed due to an insufficient number of cases, and we were unable to evaluate vasovagal symptoms.

CONFLICT OF INTEREST

None.

Modes of carbon dioxide delivery during laparoscopy generate distinct differences in peritoneal damage and hypoxia in a porcine model

BACKGROUND

Insufflation with CO₂ can employ continuous flow, recirculated gas and/or additional warming and humidification. The ability to compare these modes of delivery depends upon the assays employed and opportunities to minimize subject variation. The use of pigs to train colorectal surgeons provided an opportunity to compare three modes of CO₂ delivery under controlled circumstances.

METHODS

Sixteen pigs were subjected to rectal resection, insufflated with dry-cold CO₂ (DC-CO₂) (n = 5), recirculated CO₂ by an AirSeal device (n = 5) and humidification and warming (HW-CO2) by a HumiGard device (n = 6). Peritoneal biopsies were harvested from the same region of the peritoneum for fixation for immunohistochemistry for hypoxia-inducible factor 1 alpha (HIF-1α) and scanning electron microscopy (SEM) to evaluate hypoxia induction or tissue/cellular damage, respectively.

RESULTS

DC-CO₂ insufflation by both modes leads to significant damage to mesothelial cells as measured by cellular bulging and retraction as well as microvillus shortening compared with HW-CO₂ at 1 to 1.5 h. DC-CO₂ also leads to a rapid and significant induction of HIF-1α compared with HW-CO₂.

CONCLUSIONS

DC-CO₂ insufflation induces substantive cellular damage and hypoxia responses within the first hour of application. The use of HW-CO₂ insufflation ameliorates these processes for the first one to one and half hours in a large mammal used to replicate surgery in humans.

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.

Effect of pneumoperitoneum with warmed humidified or standard-temperature carbon dioxide during laparoscopy on core body temperature, cardiorespiratory and thromboelastography variables, systemic inflammation, peritoneal response, and signs of postoperative pain in healthy mature dogs

OBJECTIVE To evaluate effects of pneumoperitoneum created with warmed humidified CO₂ (WHCO₂) during laparoscopy on core body temperature, cardiorespiratory and thromboelastography variables, systemic inflammation, peritoneal response, and signs of postoperative pain in healthy mature dogs. ANIMALS 6 mature purpose-bred dogs. PROCEDURES In a randomized crossover study, each dog was anesthetized twice, and pneumoperitoneum was created with standard-temperature CO₂ (STCO₂; 22°C and 0% relative humidity) and WHCO₂ (37°C and 98% relative humidity). Data were collected during each procedure, including core body temperature, cardiorespiratory and thromboelastography variables, and inflammatory biomarkers. Peritoneal biopsy specimens were collected and evaluated with scanning electron microscopy. Dogs were assessed for signs of postoperative pain. RESULTS Mean core body temperature was significantly lower (35.2°C; 95% confidence interval, 34.5° to 35.8°C) with WHCO₂ than with STCO₂ (35.9°C; 95% confidence interval, 35.3° to 36.6°C) across all time points. Cardiac index increased during the procedure for both treatments but was not significantly different between treatments. Thromboelastography variables did not differ significantly between treatments as indicated by the coagulation index. Subjective evaluation of peritoneal biopsy specimens revealed mesothelial cell loss with STCO₂. There was no significant difference in circulating C-reactive protein or interleukin-6 concentrations. There was a significant increase in the number of postoperative pain scores > 0 for the WHCO₂ treatment versus the STCO₂ treatment. CONCLUSIONS AND CLINICAL RELEVANCE Analysis of these data suggested that effects on evaluated variables attributable to the use of WHCO₂ for creating pneumoperitoneum in healthy mature dogs undergoing laparoscopy did not differ from effects for the use of STCO₂.

Increased visceral tissue perfusion with heated, humidified carbon dioxide insufflation during open abdominal surgery in a rodent model

Tissue perfusion during surgery is important in reducing surgical site infections and promoting healing. This study aimed to determine if insufflation of the open abdomen with heated, humidified (HH) carbon dioxide (CO2) increased visceral tissue perfusion and core body temperature during open abdominal surgery in a rodent model. Using two different rodent models of open abdominal surgery, visceral perfusion and core temperature were measured. Visceral perfusion was investigated using a repeated measures crossover experiment with rodents receiving the same sequence of two alternating treatments: exposure to ambient air (no insufflation) and insufflation with HH CO2. Core body temperature was measured using an independent experimental design with three treatment groups: ambient air, HH CO2 and cold, dry (CD) CO2. Visceral perfusion was measured by laser speckle contrast analysis (LASCA) and core body temperature was measured with a rectal thermometer. Insufflation with HH CO2 into a rodent open abdominal cavity significantly increased visceral tissue perfusion (2.4 perfusion units (PU)/min (95% CI 1.23-3.58); p<0.0001) compared with ambient air, which significantly reduced visceral blood flow (-5.20 PU/min (95% CI -6.83- -3.58); p<0.0001). Insufflation of HH CO2 into the open abdominal cavity significantly increased core body temperature (+1.15 ± 0.14°C) compared with open cavities exposed to ambient air (-0.65 ± 0.52°C; p = 0.037), or cavities insufflated with CD CO2 (-0.73 ± 0.33°C; p = 0.006). Abdominal visceral temperatures also increased with HH CO2 insufflation compared with ambient air or CD CO2, as shown by infrared thermography. This study reports for the first time the use of LASCA to measure visceral perfusion in open abdominal surgery and shows that insufflation of open abdominal cavities with HH CO2 significantly increases visceral tissue perfusion and core body temperature.

Managing Postoperative Pain After Minimally Invasive Gynecologic Surgery in the Era of the Opioid Epidemic

In this review, we examine the evidence behind nonopioid medication alternatives, peripheral nerve blocks, surgical techniques, and postoperative recovery protocols that can help minimize and effectively treat postoperative pain after minimally invasive gynecologic surgery (MIGS). Because of the depth and heterogeneity of the data, a narrative review was performed of reported interventions. A comprehensive review was performed of PubMed, Embase, and the Cochrane Database with a focus on randomized controlled trials. In the absence of literature specific to benign gynecology, similar specialty or procedural data were reviewed. A variety of nonopioid medications, surgical techniques, and postoperative recovery protocols have shown significant improvements in postoperative pain after gynecologic surgery. Nonopioid medication options that are beneficial include acetaminophen, nonsteroidal anti-inflammatories, and antiepileptics. Incision infiltration with local anesthesia also significantly reduces pain. Surgically, minimally invasive approaches, reducing the laparoscopic trocar size to <10 mm, and evacuating the pneumoperitoneum at the end of the case all have significant benefits. Lastly, enhanced recovery pathways show promise in reducing pain after MIGS. By using a multimodal approach, minimally invasive gynecologic surgeons can help to minimize and manage postoperative pain with less reliance on opioid pain medications.

Prevention of hypothermia in patients undergoing orthotopic liver transplantation using the humigard® open surgery humidification system: a prospective randomized pilot and feasibility clinical trial

Background

Perioperative thermal disturbances during orthotopic liver transplantation (OLT) are common. We hypothesized that in patients undergoing OLT the use of a humidified high flow CO₂ warming system maintains higher intraoperative temperatures when compared to standardized multimodal strategies to maintain thermoregulatory homeostasis.

Methods

We performed a randomized pilot study in adult patients undergoing primary OLT. Participants were randomized to receive either open wound humidification with a high flow CO₂ warming system in addition to standard care (Humidification group) or to standard care alone (Control group). The primary end point was nasopharyngeal core temperature measured 5 min immediately prior to reperfusion of the donor liver (Stage 3 − 5 min). Secondary endpoints included intraoperative PaCO₂, minute ventilation and the use of vasoconstrictors.

Results

Eleven patients were randomized to each group. Both groups were similar for age, body mass index, MELD, SOFA and APACHE II scores, baseline temperature, and duration of surgery. Immediately prior to reperfusion (Stage 3 − 5 min) the mean (SD) core temperature was higher in the Humidification Group compared to the Control Group: 36.0 °C (0.13) vs. 35.4 °C (0.22), p = 0.028. Repeated measured ANOVA showed that core temperatures over time during the stages of the transplant were higher in the Humidification Group compared to the Control Group (p < 0.0001). There were no significant differences in the ETCO₂, PaCO₂, minute ventilation, or inotropic support.

Conclusion

The humidified high flow CO₂ warming system was superior to standardized multimodal strategies in maintaining normothermia in patients undergoing OLT. Use of the device was feasible and did not interfere with any aspects of surgery. A larger study is needed to investigate if the improved thermoregulation observed is associated with improved patient outcomes.

Trial registration

ACTRN12616001631493. Retrospectively registered 25 November 2016.

Management of Postoperative Pain: A Clinical Practice Guideline From the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists' Committee on Regional Anesthesia, Executive Committee, and Administrative Council

Most patients who undergo surgical procedures experience acute postoperative pain, but evidence suggests that less than half report adequate postoperative pain relief. Many preoperative, intraoperative, and postoperative interventions and management strategies are available for reducing and managing postoperative pain. The American Pain Society, with input from the American Society of Anesthesiologists, commissioned an interdisciplinary expert panel to develop a clinical practice guideline to promote evidence-based, effective, and safer postoperative pain management in children and adults. The guideline was subsequently approved by the American Society for Regional Anesthesia. As part of the guideline development process, a systematic review was commissioned on various aspects related to various interventions and management strategies for postoperative pain. After a review of the evidence, the expert panel formulated recommendations that addressed various aspects of postoperative pain management, including preoperative education, perioperative pain management planning, use of different pharmacological and nonpharmacological modalities, organizational policies, and transition to outpatient care. The recommendations are based on the underlying premise that optimal management begins in the preoperative period with an assessment of the patient and development of a plan of care tailored to the individual and the surgical procedure involved. The panel found that evidence supports the use of multimodal regimens in many situations, although the exact components of effective multimodal care will vary depending on the patient, setting, and surgical procedure. Although these guidelines are based on a systematic review of the evidence on management of postoperative pain, the panel identified numerous research gaps. Of 32 recommendations, 4 were assessed as being supported by high-quality evidence, and 11 (in the areas of patient education and perioperative planning, patient assessment, organizational structures and policies, and transitioning to outpatient care) were made on the basis of low-quality evidence.

PERSPECTIVE

This guideline, on the basis of a systematic review of the evidence on postoperative pain management, provides recommendations developed by a multidisciplinary expert panel. Safe and effective postoperative pain management should be on the basis of a plan of care tailored to the individual and the surgical procedure involved, and multimodal regimens are recommended in many situations.

Five year follow-up of a randomized controlled trial on warming and humidification of insufflation gas in laparoscopic colonic surgery--impact on small bowel obstruction and oncologic outcomes

Warming and humidification of insufflation gas has been shown to reduce adhesion formation and tumor implantation in the laboratory setting, but clinical evidence is lacking. We aimed to test the hypothesis that warming and humidification of insufflation CO2 would lead to reduced adhesion formation, and improve oncologic outcomes in laparoscopic colonic surgery. This was a 5-year follow-up of a multicenter, double-blinded, randomized, controlled trial investigating warming and humidification of insufflation gas. The study group received warmed (37°C), humidified (98%) insufflation carbon dioxide, and the control group received standard gas (19°C, 0%). All other aspects of patient care were standardized. Admissions for small bowel obstruction were recorded, as well as whether management was operative or nonoperative. Local and systemic cancer recurrence, 5-year overall survival, and cancer specific survival rates were also recorded. Eighty two patients were randomized, with 41 in each arm. Groups were well matched at baseline. There was no difference between the study and control groups in the rate of clinical small bowel obstruction (5.7% versus 0%, P 0.226); local recurrence (6.5% versus 6.1%, P 1.000); overall survival (85.7% versus 82.1%, P 0.759); or cancer-specific survival (90.3% versus 87.9%, P 1.000). Warming and humidification of insufflation CO2 in laparoscopic colonic surgery does not appear to confer a clinically significant long term benefit in terms of adhesion reduction or oncological outcomes, although a much larger randomized controlled trial (RCT) would be required to confirm this. ClinicalTrials.gov Trial identifier: NCT00642005; US National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, USA.

Heated insufflation with or without humidification for laparoscopic abdominal surgery

BACKGROUND

Intraoperative hypothermia during both open and laparoscopic abdominal surgery may be associated with adverse events. For laparoscopic abdominal surgery, the use of heated insufflation systems for establishing pneumoperitoneum has been described to prevent hypothermia. Humidification of the insufflated gas is also possible. Past studies on heated insufflation have shown inconclusive results with regards to maintenance of core temperature and reduction of postoperative pain and recovery times.

OBJECTIVES

To determine the effect of heated gas insufflation compared to cold gas insufflation on maintaining intraoperative normothermia as well as patient outcomes following laparoscopic abdominal surgery.

SEARCH METHODS

We searched Cochrane Colorectal Cancer Specialised Register (September 2016), the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2016, Issue 8), Ovid MEDLINE (1950 to September 2016), Ovid Embase (1974 to September 2016), International Pharmaceutical Abstracts (IPA) (September 2016), Web of Science (1985 to September 2016), Scopus, www.clinicaltrials.gov and the National Research Register (1956 to September 2016). We also searched grey literature and cross references. Searches were limited to human studies without language restriction.

SELECTION CRITERIA

Only randomised controlled trials comparing heated (with or without humidification) with cold gas insufflation in adult and paediatric populations undergoing laparoscopic abdominal procedures were included. We assessed study quality in regards to relevance, design, sequence generation, allocation concealment, blinding, possibility of incomplete data and selective reporting. Two review authors independently selected studies for the review, with any disagreement resolved in consensus with a third co-author.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed screening of eligible studies, data extraction and methodological quality assessment of the trials. We classified a study as low-risk of bias if all of the first six main criteria indicated in the 'Risk of Bias Assessment' table were assessed as low risk. We used data sheets to collect data from eligible studies. We presented results using mean differences for continuous outcomes and relative risks for dichotomous outcomes, with 95% confidence intervals. We used Review Manager (RevMan) 5.3 software to calculate the estimated effects. We took publication bias into consideration and compiled funnel plots.

MAIN RESULTS

We included 22 studies in this updated analysis, including six new trials with 584 additional participants, resulting in a total of 1428 participants. The risk of bias was low in 11 studies, high in one study and unclear in the remaining studies, due primarily to failure to report methodology for randomisation, and allocation concealment or blinding, or both. Fourteen studies examined intraoperative core temperatures among heated and humidified insufflation cohorts and core temperatures were higher compared to cold gas insufflation (MD 0.31 °C, 95% CI, 0.09 to 0.53, I2 = 88%, P = 0.005) (low-quality evidence). If the analysis was limited to the eight studies at low risk of bias, this result became non-significant but remained heterogeneous (MD 0.18 °C, 95% CI, -0.04 to 0.39, I2= 81%, P = 0.10) (moderate-quality evidence).In comparison to the cold CO2 group, the meta-analysis of the heated, non-humidified group also showed no statistically significant difference between groups. Core temperature was statistically, significantly higher in the heated, humidified CO2 with external warming groups (MD 0.29 °C, 95% CI, 0.05 to 0.52, I2 = 84%, P = 0.02) (moderate-quality evidence). Despite the small difference in temperature of 0.31 °C with heated CO2, this is unlikely to be of clinical significance.For postoperative pain scores, there were no statistically significant differences between heated and cold CO2, either overall, or for any of the subgroups assessed. Interestingly, morphine-equivalent use was homogeneous and higher in heated, non-humidified insufflation compared to cold insufflation for postoperative day one (MD 11.93 mg, 95% CI 0.92 to 22.94, I2 = 0%, P = 0.03) (low-quality evidence) and day two (MD 9.79 mg, 95% CI 1.58 to 18.00, I2 = 0%, P = 0.02) (low-quality evidence). However, morphine use was not significantly different six hours postoperatively or in any humidified insufflation groups.There was no apparent effect on length of hospitalisation, lens fogging or length of operation with heated compared to cold gas insufflation, with or without humidification. Recovery room time was shorter in the heated cohort (MD -26.79 minutes, 95% CI -51.34 to -2.25, I2 = 95%, P = 0.03) (low-quality evidence). When the one and only unclear-risk study was removed from the analysis, the difference in recovery-room time became non-significant and the studies were statistically homogeneous (MD -1.22 minutes, 95% CI, -6.62 to 4.17, I2 = 12%, P = 0.66) (moderate-quality evidence).There were also no differences in the frequency of major adverse events that occurred in the cold or heated cohorts.These results should be interpreted with caution due to some limitations. Heterogeneity of core temperature remained significant despite subgroup analysis, likely due to variations in the study design of the individual trials, as the trials had variations in insufflation gas temperatures (35 ºC to 37 ºC), humidity ranges (88% to 100%), gas volumes and location of the temperature probes. Additionally, some of the trials lacked specific study design information making evaluation difficult.

AUTHORS' CONCLUSIONS

While heated, humidified gas leads to mildly smaller decreases in core body temperatures, clinically this does not account for improved patient outcomes, therefore, there is no clear evidence for the use of heated gas insufflation, with or without humidification, compared to cold gas insufflation in laparoscopic abdominal surgery.

Warmed and humidified carbon dioxide for abdominal laparoscopic surgery: meta-analysis of the current literature

BACKGROUND

The creation of a pneumoperitoneum for laparoscopic surgery is performed by the insufflation of carbon dioxide (CO₂). The insufflated CO₂ is generally at room temperature (20-25 °C) and dry (0-5 % relative humidity). However, these physical characteristics could lead to alterations of the peritoneal cavity, leading to operative and postoperative complications. Warming and humidifying the insufflated gas has been proposed to reduce the iatrogenic effects of laparoscopic surgery, such as pain, hypothermia and peritoneal alterations. Two medical devices are currently available for laparoscopic surgery with warm and humidified CO₂.

METHODS

Clinical studies were identified by searching PubMed with keywords relating to humidified and warmed CO₂ for laparoscopic procedures. Analysis of the literature focused on postoperative pain, analgesic consumption, duration of hospital stay and convalescence, surgical techniques and hypothermia.

RESULTS

Bibliographic analyses reported 114 publications from 1977 to 2015, with only 17 publications of clinical interest. The main disciplines focused on were gynaecological and digestive surgery ). Analysis of the studies selected reported only a small beneficial effect of warmed and humidified laparoscopy compared to standard laparoscopy on immediate postoperative pain and per procedure hypothermia. No difference was observed for later postoperative shoulder pain, morphine equivalent daily doses, postoperative body core temperature, recovery room and hospital length of stay, lens fogging and procedure duration.

CONCLUSIONS

Only few beneficial effects on immediate postoperative pain and core temperature have been identified in this meta-analysis. Although more studies are probably needed to close the debate on the real impact of warmed and humidified CO₂ for laparoscopic procedures.

Abdominal anatomy in the context of port placement and trocars

Although the anatomy of the human being has not changed, technical developments in operating materials and methods demand a simultaneous development in operative management. Developments in electronic and optical technologies permit many gynecological operations to be performed laparoscopically. One fundamental distinction between any other operating method and laparoscopy is the hurdle that the initial entry, whether with a needle, cannula, or trocar, is mostly performed blind. However, there is a risk that blind entry may result in vascular or organ damage. One of the difficulties associated with entry complications is that any damage may not be immediately recognized, leading to major abdominal reparative surgery, and at worst, a temporary colostomy. Therefore, the technical and operative quality of laparoscopic surgery begins with port placement and trocars. Visual access systems are available but are not yet widely used. The aim of this review was to introduce the different port placement and trocar systems as well as their correct and professional usage in correlation with the abdominal functional anatomy.

Humidification during laparoscopic surgery: overview of the clinical benefits of using humidified gas during laparoscopic surgery

PURPOSE

The peritoneum is the serous membrane that covers the abdominal cavity and most of the intra-abdominal organs. It is a very delicate layer highly susceptible to damage and it is not designed to cope with variable conditions such as the dry and cold carbon dioxide (CO2) during laparoscopic surgery. The aim of this review was to evaluate the effects caused by insufflating dry and cold gas into the abdominal cavity after laparoscopic surgery.

METHODS

A literature search using the Pubmed was carried out. Articles identified focused on the key issues of laparoscopy, peritoneum, morphology, pneumoperitoneum, humidity, body temperature, pain, recovery time, post-operative adhesions and lens fogging.

RESULTS

Insufflating dry and cold CO2 into the abdomen causes peritoneal damage, post-operative pain, hypothermia and post-operative adhesions. Using humidified and warm gas prevents pain after surgery. With regard to hypothermia due to desiccation, it can be fully prevented using humidified and warm gas. Results relating to the patient recovery are still controversial.

CONCLUSIONS

The use of humidified and warm insufflation gas offers a significant clinical benefit to the patient, creating a more physiologic peritoneal environment and reducing the post-operative pain and hypothermia. In animal models, although humidified and warm gas reduces post-operative adhesions, humidified gas at 32 °C reduced them even more. It is clear that humidified gas should be used during laparoscopic surgery; however, a question remains unanswered: to achieve even greater clinical benefit to the patient, at what temperature should the humidified gas be when insufflated into the abdomen? More clinical trials should be performed to resolve this query.

Insufflation with humidified and heated carbon dioxide in short-term laparoscopy: a double-blinded randomized controlled trial

Background. We tested the hypothesis that warm-humidified carbon dioxide (CO₂) insufflation would reduce postoperative pain and morphine requirement compared to cold-dry CO₂ insufflation. Methods. A double-blinded, randomized, controlled trial was conducted to compare warm, humidified CO₂ and cold-dry CO₂. Patients with benign uterine diseases were randomized to either treatment (n = 48) or control (n = 49) group during laparoscopically assisted vaginal hysterectomy. Primary endpoints of the study were rest pain, movement pain, shoulder-tip pain, and cough pain at 2, 4, 6, 24, and 48 hours postoperatively, measured by visual analogue scale. Secondary outcomes were morphine consumption, rejected boli, temperature change, recovery room stay, and length of hospital stay. Results. There were no significant differences in all baseline characteristics. Shoulder-tip pain at 6 h postoperatively was significantly reduced in the intervention group. Pain at rest, movement pain, and cough pain did not differ. Total morphine consumption and rejected boli at 24 h postoperatively were significantly higher in the control group. Temperature change, recovery room stay, and length of hospital were similar. Conclusions. Warm, humidified insufflation gas significantly reduces postoperative shoulder-tip pain as well as morphine demand. This trial is registered with Clinical Trial Registration Number   DRKS00003853 (German Clinical Trials Register (DRKS)).

Influence of pneumoperitoneum pressure on surgical field during robotic and laparoscopic surgery: a comparative study

PURPOSE

Studies on the influence of CO₂ pneumoperitoneum on the abdominal cavity during robotic procedures are lacking. This is the first study to evaluate surgical field modifications related to CO₂ pressure, during laparoscopic and robotic surgery.

METHODS

Consecutive patients scheduled for laparoscopic or robotic hysterectomy were enrolled in the study. To evaluate the level of operative field visualization, a dedicated form has been designed based on the evaluation of four different areas: Douglas space, vesico-uterine fold and, bilaterally, the broad ligament. During the initial inspection, an assistant randomly set the CO₂ pressure at 15, 10 and 5 mmHg, and the surgeon, not aware of the CO₂ values, was asked to give an evaluation of the four areas for each set pressure.

RESULTS

In laparoscopic group, CO₂ pressure significantly influenced the surgical field visualization in all four areas analyzed. The surgeon had a good visualization only at 15 mmHg CO₂ pressure; visualization decreased with a statistically significant difference from 15 to 5, 15-10 and 10-5 mmHg. In robotic group, influence of CO₂ pressure on surgical areas visualization was not straightforward; operative field visualization remained stable at any pressure value with no significant difference.

CONCLUSIONS

Pneumoperitoneum pressure significantly affects the visualization of the abdomino-pelvic cavity in laparoscopic procedures. Otherwise, CO₂ pressure does not affect the visualization of surgical field during robotic surgery. These findings are particularly significant especially at low CO₂ pressure with potential implications on peritoneal environment and the subsequent post-operative patient recovery.

Treating postlaparoscopic surgery shoulder pain with acupuncture

Objective. The purpose of this study was to examine the effect of acupuncture on postlaparoscopic shoulder pain (PLSP) which is a common side effect in patients undergoing abdominal laparoscopic surgery. Methods. Patients with moderate to severe PLSP in spite of analgesic treatment, which were referred by the medical staff to the Complementary-Integrative Surgery Service (CISS) at our institution, were provided with acupuncture treatment. The severity of PLSP and of general pain was assessed using a Visual Analogue Scale (VAS) from 0 to 10. Pain assessment was conducted prior to and two hours following acupuncture treatment. Acupuncture treatment was individualized based on traditional Chinese medicine diagnosis. Results. A total of 25 patients were evaluated during a 14-month period, from March 2011 to May 2012. A significant reduction in PLSP (mean reduction of 6.4 ± 2.3 P < 0.0001) and general pain (mean reduction 6.4 ± 2.1 P < 0.0001) were observed, and no significant side effects were reported. Conclusion. Individualized acupuncture treatments according to traditional Chinese medicine principles may improve postlaparoscopic shoulder pain and general pain when used in conjunction with conventional therapy. The primary findings of this study warrant verification in controlled studies.

Impact of intraoperative temperature and humidity on healing of intestinal anastomoses

PURPOSE

Clinical data indicate that laparoscopic surgery has a beneficial effect on intestinal wound healing and is associated with a lower incidence of anastomotic leakage. This observation is based on weak evidence, and little is known about the impact of intraoperative parameters during laparoscopic surgery, e.g., temperature and humidity.

METHODS

A small-bowel anastomosis was formed in rats inside an incubator, in an environment of stable humidity and temperature. Three groups of ten Wistar rats were operated: a control group (G1) in an open surgical environment and two groups (G2 and G3) in the incubator at a humidity of 60 % and a temperature of 30 and 37 °C (G2 and G3, respectively). After 4 days, bursting pressure and hydroxyproline concentration of the anastomosis were analyzed. The tissue was histologically examined. Serum levels of C-reactive-protein (CRP) were measured.

RESULTS

No significant changes were seen in the evaluation of anastomotic stability. Bursting pressure was very similar among the groups. Hydroxyproline concentration in G3 (36.3 μg/g) was lower by trend (p = 0.072) than in G1 (51.7 μg/g) and G2 (46.4 μg/g). The histological evaluation showed similar results regarding necrosis, inflammatory cells, edema, and epithelization for all groups. G3 (2.56) showed a distinctly worse score for submucosal bridging (p = 0.061) than G1 (1.68). A highly significant increase (p = 0.008) in CRP was detected in G3 (598.96 ng/ml) compared to G1 (439.49 ng/ml) and G2 (460 ng/ml).

CONCLUSION

A combination of high temperature and humidity during surgery induces an increased systemic inflammatory response and seems to be attenuating the early regeneration process in the anastomotic tissue.

Warm, humidified carbon dioxide gas insufflation for laparoscopic appendicectomy in children: a double-blinded randomized controlled trial

OBJECTIVE

To investigate clinical benefits of warm, humidified carbon dioxide (CO(2)) insufflation for acute laparoscopic appendicectomy on postoperative pain and recovery in children (age 8-14 years).

BACKGROUND

Conventional CO(2) insufflation leads to desiccation-related peritoneal inflammation and injury, which is preventable with warm, humidified CO2 gas. We hypothesized that reduced peritoneal desiccation would improve patient-centered outcomes in children after laparoscopic appendicectomy.

METHOD

A double-blinded, randomized controlled trial was conducted. Intervention group participants received warm (37°C), humidified (98% relative humidity) CO(2) gas insufflation, whereas control participants received standard room temperature (20°C) gas with 0% relative humidity. Perioperative analgesia and anesthesia were standardized. Postoperative opiate usage was converted to morphine equivalent daily dosages (MEDD) for comparison, and pain intensity at rest and on moving was rated by participants using visual analog scales. Postoperative recovery and return to normal activities was assessed using a questionnaire on day 10.

RESULTS

Between February 2010 and March 2011, a total of 190 participants were randomized. Both intervention and control groups were matched at baseline. Postoperative MEDD and pain scores were also similar. There were no differences in postoperative recovery parameters.

CONCLUSIONS

Warm, humidified CO(2) insufflation for acute laparoscopic appendicectomy has no short-term clinical benefits on postoperative outcomes in pediatric patients (ClinicalTrials.gov trial identifying code: NCT01027455).

Prevention of vessel desiccation and maintenance of normal morphology during endovascular harvesting using humidified warmed gas

Dry, cold CO₂ gas was found to cause tissue damage during endovascular harvest. The use of warmed, humidified CO₂ gas appeared to maintain vessel morphology and integrity during endovascular harvest by preventing tissue desiccation.

Background and Objectives:

Endoscopic vessel harvesting (EVH) traditionally uses carbon dioxide (CO₂) gas for insufflation. The CO₂ based on government regulations is bone dry and room temperature. All previous EVH studies use this type of unconditioned gas. It is hypothesized that by changing the quality of CO₂ gas differences may occur that are attributable to dry gas versus wet gas exposure.

Methods:

A comparison of the effect(s) of traditional dry CO₂ gas compared to humidified exposure was done using a porcine model and evaluated in a double-blind randomized controlled fashion.

Results:

Vessels exposed to traditional dry cold gas had morphologic and structural changes noted on histologic evaluation. This included desiccation changes of the tunica adventitia desiccation and tunica media collagen and elastin. Vessels exposed to dry gas showed 10% to 12% contraction and constriction with tortuous changes to the intima and endothelial lining that were progressive with increasing volumes of gas exposure. No desiccation or morphologic changes were seen with humidified warmed gas produced using the VesselGuardian.

Conclusions:

Traditional dry cold CO₂ caused vascular tissue damage extending from the adventitia to intima, changing the vessel in morphologic and structural configuration. With the VesselGuardian humidified warmed, gas maintained vessel morphology and integrity by preventing desiccation. Changing the quality of CO₂ from dry and cold to wet and warm may offer clinical utility for a better quality conduit for coronary artery bypass graft procedures.

Optimizing perioperative care in bariatric surgery patients

Enhanced recovery after surgery (ERAS) programs have been shown to minimise morbidity in other types of surgery, but comparatively less data exist investigating ERAS in bariatric surgery. This article reviews the existing literature to identify interventions which may be included in an ERAS program for bariatric surgery. A narrative literature review was conducted. Search terms included 'bariatric surgery', 'weight loss surgery', 'gastric bypass', 'ERAS', 'enhanced recovery', 'enhanced recovery after surgery', 'fast-track surgery', 'perioperative care', 'postoperative care', 'intraoperative care' and 'preoperative care'. Interventions recovered by the database search, as well as interventions garnered from clinical experience in ERAS, were used as individual search terms. A large volume of evidence exists detailing the role of multiple interventions in perioperative care. However, efficacy and safety for a proportion of these interventions for ERAS in bariatric surgery remain unclear. This review concludes that there is potential to implement ERAS programs in bariatric surgery.

Comparison of warm and cold contrast media for hysterosalpingography: a prospective, randomized study

OBJECTIVE

To compare the use of warm medium and cold medium for alleviating pain and side effects during hysterosalpingography (HSG).

DESIGN

Prospective randomized study.

SETTING

University hospital.

PATIENT(S)

Two hundred infertile women who needed HSG were recruited from January 2010 to June 2011. The exclusion criteria were acute low reproductive duct infection, known hypersensitivity to iodine, genital bleeding, or malignancy.

INTERVENTION(S)

Subjects were randomized to undergo HSG using a medium prewarmed to 37°C or a medium at room temperature.

MAIN OUTCOME MEASURE(S)

Incidence of vasovagal episodes and visual analog scale (VAS) pain scores during HSG.

RESULT(S)

Patients' VAS pain scores during HSG were significantly lower in the warm media group initially but showed no statistical difference at 30 minutes after injection. Medium temperature showed a linear association with VAS score. The total number of vasovagal episodes was higher in the cold medium group.

CONCLUSION(S)

Warm contrast medium alleviates the pain associated with HSG and decreases the incidence of vasovagal episodes during HSG.

CLINICAL TRIALS REGISTRATION NUMBER

NCT01339338.

Shakespeare's view of the laparoscopic pneumoperitoneum

Shakespeare's premonition regarding chilling effects and intentionally induced unhappy events perpetrated on the peritoneal cavity is not, nor cannot, come to good.

Background:

The laparoscopic pneumoperitoneum is created and maintained in a physiologically homeostatic potential space that is 37-degrees Centigrade (^oC) and covered by a wet film of peritoneal fluid. The currently used gas is carbon dioxide that is instilled at 21^oC and extremely dry. Altering this privileged space is a violation of surgical safety, principles, and reason. Maintaining normal healthy conditions in their original state by humidifying and warming the gas eliminates the rub of dry gas and takes arms against a sea of troubles.

Database:

Literature search using PubMed and Cochrane databases identifying articles focusing on laparoscopy, pneumoperitoneum, hypothermia, evaporation, desiccation, peritoneum, and morphology.

Conclusions:

Shakespeare's premonitions regarding the chilling effects and intentionally induced unhappy events perpetrated on the peritoneal cavity is not nor cannot come to good. The absence of water in the gas going into a wetted cavity causes perilous circumstances, resulting in evaporative hypothermia, tissue desiccation, and damage that precede adhesion formation. Providing the most protective canopy for the intraabdominal cavity with humidity and warmth prevents calamitous clinical outcomes and mirrors nature's intent. The virtue is in doing no harm.

Intraperitoneal temperature and desiccation during endoscopic surgery. Intraoperative humidification and cooling of the peritoneal cavity can reduce adhesions

This study was conducted to document quantitatively the intraperitoneal temperature and desiccation during laparoscopic surgery. The temperature, relative humidity, and flow rate were measured in vitro and during laparoscopic surgery, at the entrance and at the exit of the abdomen. This permitted us to calculate desiccation for various flow rates using either dry CO(2) or CO(2) humidified with 100% relative humidity at any preset temperature between 25 and 37°C. The study showed that desiccation, both in vitro and in vivo, varies as expected with the flow rates and relative humidity while intraperitoneal temperature varies mainly with desiccation. Temperature regulation of bowels is specific and drops to the intraperitoneal temperature without affecting core body temperature. With a modified humidifier, desiccation could be eliminated while maintaining the intraperitoneal temperature between 31 to 32°C.

Postoperative analgesia for gynecological laparoscopy

Gynecological laparoscopy is a commonly performed procedure. Providing anesthesia for this can present a challenge, particularly in the day surgery population. Poor analgesia, nausea, and vomiting can cause distress to the patient and increased cost for the health system, because of overnight admission. In this review we discuss anesthetic and analgesic techniques for day-case gynecological laparoscopy. The principles include multimodal analgesia, the use of the oral route wherever possible, and the contribution of the surgeon.

Warming and humidification have no effect on oxidative stress during pneumoperitoneum in rats

Pneumoperitoneum is reported to induce oxidative stress due to the desiccative effect of cold, dry gas insufflation. The aim of this study is to compare the effect of warmed, humidified insufflation to standard gas, by measuring oxidative stress markers in a physiologically relevant animal model. Twenty male Wistar rats (330?650 g) were alternately assigned to the Warm Humidified group (WH, n = 10) and Control group (n = 10). All rats underwent pneumoperitoneum at 5 mmHg and a controlled flow rate for 110 min. The WH group received warmed (37?C) and humidified (98% Relative Humidity (RH)) gas and the control group received standard gas at room temperature (19?C) and 0% RH. At the end of pneumoperitoneum, samples of liver, kidney, pancreas, jejunum, and lung were excised. Levels of plasma and tissue malondialdehyde (MDA) and protein carbonyls (PC) were measured. Organ light microscopy was performed. There were no differences between groups for MDA or PC concentrations in plasma, liver, kidney, jejunum, or lung tissue. There were no differences in histological score between groups. Warming and humidification of pneumoperitoneum insufflation gas have no effect on measures of oxidative stress compared to non-warmed, non-humidified controls.

Heated CO(2) with or without humidification for minimally invasive abdominal surgery

BACKGROUND

Intraoperative hypothermia during both open and laparoscopic abdominal surgery may be associated with adverse events. For laparoscopic abdominal surgery, the use of heated insufflation systems for establishing pneumoperitoneum has been described to prevent hypothermia. Humidification of the insufflated gas is also possible. Past studies have shown inconclusive results with regards to maintenance of core temperature and reduction of postoperative pain and recovery times.

OBJECTIVES

To determine the effect of heated gas insufflation on patient outcomes following minimally invasive abdominal surgery.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (PubMed), EMBASE, International Pharmaceutical Abstracts (IPA), Web of Science, Scopus, www.clinicaltrials.gov and the National Research Register were searched (1956 to 14 June 2010). Grey literature and cross-references were also searched. Searches were limited to human studies without language restriction.

SELECTION CRITERIA

All included studies were randomized trials comparing heated (with or without humidification) gas insufflation with cold gas insufflation in adult and pediatric populations undergoing minimally invasive abdominal procedures. Study quality was assessed in regards to relevance, design, sequence generation, allocation concealment, blinding, possibility of incomplete data and selective reporting. The selection of studies for the review was done independently by two authors, with any disagreement resolved in consensus with a third co-author.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, data extraction and methodological quality assessment of the trials were performed by the authors. Data from eligible studies were collected using data sheets. Results were presented using mean differences for continuous outcomes and relative risks with 95% confidence intervals for dichotomous outcomes. The estimated effects were calculated using the latest version of RevMan software. Publication bias was taken into consideration and funnel plots were compiled.

MAIN RESULTS

Sixteen studies were included in the analysis. During laparoscopic abdominal surgery, no effect on postoperative pain nor changes in core temperature, morphine consumption, length of hospitalisation, lens fogging, length of operation or recovery room stay were associated with heated compared to cold gas insufflation with or without humidification.

AUTHORS' CONCLUSIONS

The study offers evidence that during laparoscopic abdominal surgery, heated gas insufflation, with or without humidification, has minimal benefit on patient outcomes.

Gut oxygenation and oxidative damage during and after laparoscopic and open left-sided colon resection: a prospective, randomized, controlled clinical trial

BACKGROUND

Pneumoperitoneum (PP), established for laparoscopic (LPS) operation, has been associated with potential detrimental effects, such as mesenteric ischemia-reperfusion injury. The objective of the trial was to measure intestinal tissue oxygen pressure (PtiO2) and oxidative damage during laparoscopic (LPS) and open colon surgery and during the postoperative course.

METHODS

Forty patients candidate to left-sided colectomy were randomized to undergo open or LPS resection (20 patients/group). During the operation, PtiO2 was measured at established changes of PP pressure (from 0-15 mmHg) and for 6 days postoperatively. PtiO2 was determined by a polarographic microprobe implanted in the colon wall. Ischemia-reperfusion injury was assessed by plasma malondialdehyde (MDA). ClinicalTrial.gov registration number: NCT01040013.

RESULTS

LPS was associated with a higher PtiO2 at the beginning of surgery (73.9±9.4 vs. 64.3±6.4 in open; P=0.04) and at the end of the operation (57.7±7.9 vs. 53.1±4.7 in open; P=0.03). PtiO2 decreased significantly during mesentery traction vs. beginning in both groups (respectively 58.7±13.2 vs. 73.9±9.4 in LPS and 55.3±6.4 vs. 64.3±6.4 in open group; minimum P=0.02). During LPS, there was a significant decrease of PtiO2 only when PP was increased to 15 mmHg (63.2±7.5 vs. 76.6±10.7 at 10 mmHg; P=0.03). PtiO2 also was significantly better in the LPS group during the first 3 days after operation (minimum P=0.04 vs. open). MDA significantly increased in both groups after mesentery traction and at the end of operation vs. baseline levels with no difference between techniques.

CONCLUSIONS

LPS seems to be associated with a better intra- and postoperative PtiO2. High-pressure PP may impair PtiO2.

A prospective case-control study of the local and systemic cytokine response after laparoscopic versus open colonic surgery

BACKGROUND

There is a sequential, high concentration cytokine response after major abdominal surgery. The magnitude of this response has been directly linked to postoperative metabolic derangement, ileus, adhesions, and oncological outcomes. We aimed to compare the local and systemic cytokine response in laparoscopic and open colonic surgery and relate this to postoperative recovery parameters.

METHODS

Using a prospectively collected patient database, we compared a Study Group (n = 50) of patients undergoing elective laparoscopic colonic resection with a Control Group (n = 25) of patients undergoing equivalent open colonic surgery within an ERAS program. Patients were matched for age, gender, BMI, ASA, Cr Possum, side of resection, diagnosis, and histologic stage. Plasma and peritoneal fluid concentrations of IL-6, IL-8, IL-10, and TNFα were measured at 20-24 h after surgery. The Surgical Recovery Score was determined pre-operatively and at 3, 7, 30, and 60 d postoperatively. All data were prospectively collected, and a priori definitions were used for discharge parameters, complications, and complication severity.

RESULTS

Peritoneal fluid IL-6 concentration was lower after laparoscopic surgery. There were no significant differences in the other cytokines measured, or in any postoperative recovery outcomes. Significant correlations were found between cytokine levels and discharge criteria achievement, day stay, postoperative complications, and the Surgical Recovery Score.

CONCLUSION

With the exception of a lower peritoneal IL-6 level, the systemic and peritoneal cytokine response at 20-24 h is similar after laparoscopic versus open colonic resection within an ERAS program, with corresponding equivalent rates of postoperative recovery.

The humoral response after laparoscopic versus open colorectal surgery: a meta-analysis

BACKGROUND

The local and systemic humoral response after colorectal surgery is thought to affect postoperative recovery. It is commonly claimed that laparoscopic surgery elicits a diminished inflammatory response than equivalent open surgery. Despite these claims, the evidence is conflicting. Therefore, we aimed to systematically review the results from randomized controlled clinical trials comparing the humoral response associated with laparoscopic versus open colorectal surgery.

MATERIALS AND METHODS

A high-sensitivity search was conducted independently by two of the authors with no language restriction. Studies were identified from the Cochrane Central Register of Controlled Trials (CENTRAL/CCTR), Cochrane Library, Medline (January 1966 to January 2009), PubMed (1950 to January 2009), and Embase (1947 to January 2009). Relevant meeting abstracts and reference lists were manually searched. Data analysis was performed using Review Manager ver. 5.0.

RESULTS

Thirteen randomized controlled trials were included. Meta-analysis demonstrated a significantly higher serum IL-6 on d 1 after open colorectal resection for neoplasia (n = 97) compared with laparoscopic resection (n = 76, P = 0.0008) without significant heterogeneity. Data for plasma IL-6 were heterogeneous, with no apparent difference between groups. No other significant differences were identified, and there were not enough data on local peritoneal humoral factors to allow meta-analysis.

CONCLUSION

Open colorectal resection for neoplasia is associated with higher postoperative serum levels of IL-6 on d 1 than equivalent laparoscopic surgery. The aetiology and clinical significance of this finding is uncertain, and further studies are required to elucidate any differences in the local humoral response which may be more clinically relevant in surgery for this indication.

Peritoneal damage: the inflammatory response and clinical implications of the neuro-immuno-humoral axis

BACKGROUND

The peritoneum is a bilayer serous membrane that lines the abdominal cavity. We present a review of peritoneal structure and physiology, with a focus on the peritoneal inflammatory response to surgical injury and its clinical implications.

METHODS

We conducted a nonsystematic clinical review. A search of the Ovid MEDLINE database from 1950 through January 2009 was performed using the following search terms: peritoneum, adhesions, cytokine, inflammation, and surgery.

RESULTS

The peritoneum is a metabolically active organ, responding to insult through a complex array of immunologic and inflammatory cascades. This response increases with the duration and extent of injury and is central to the concept of surgical stress, manifesting via a combination of systemic effects, and local neural pathways via the neuro-immuno-humoral axis. There may be a decreased systemic inflammatory response after minimally invasive surgery; however, it is unclear whether this is due to a reduced local peritoneal reaction.

CONCLUSIONS

Interventions that dampen the peritoneal response and/or block the neuro-immuno-humoral pathway should be further investigated as possible avenues of enhancing recovery after surgery, and reducing postoperative complications.

Systematic review of oxidative stress associated with pneumoperitoneum

Background

There have been several reports of ischaemic complications after routine laparoscopy. The aim of this review was to investigate the relationship between this oxidative stress and pneumoperitoneum.

Methods

Medline, Medline in-process, The Cochrane Library, PubMed and EMBASE were searched for papers on oxidative stress and pneumoperitoneum, from 1947 to March 2008 with no language restriction or restriction on trial design. Papers that did not investigate pneumoperitoneum as a causative factor, or did not report outcome measures related to oxidative stress, were excluded.

Results

A total of 73 relevant papers were identified: 36 animal studies, 21 human clinical trials, nine case reports, five review articles and two comments. Pneumoperitoneum causes a reduction in splanchnic blood flow, resulting in biochemical evidence of oxidative stress in a pressure- and time-dependent manner. There is evidence that the use of carbon dioxide for insufflation is contributory. Several measures proposed to minimize the oxidative stress have shown promise in animal studies, but few have been evaluated in the clinical setting.

Conclusion

There is an increasing body of evidence, mainly from animal studies, that pneumoperitoneum decreases splanchnic perfusion with resulting oxidative stress. It is now appropriate to investigate the clinical significance of pneumoperitoneum-associated oxidative stress.

High flow insufflation for the maintenance of the pneumoperitoneum during bariatric surgery

Minimally invasive bariatric procedures next to becoming more and more popular have established a new field of applications for carbon dioxide (CO2) insufflators. In laparoscopic bariatric procedures, gas is used to insufflate the peritoneal cavity and increase the intra-abdominal pressure up to 15 mm Hg for optimal exposure and a suitable operating field. The increased intra-abdominal pressure during pneumoperitoneum can reduce femoral venous flow, intra-operative urine output, portal venous flow, respiratory compliance,and cardiac output. However, clinical complications related to these effects are rare. Yet, surgeons should be constantly aware that the duration of an operation is an important factor in reducing the patient's exposure to CO2 pneumoperitoneum and its adverse effects. The optimized performance of the bariatric high flow insufflator allows reaching stable abdominal pressure conditions quicker and at a higher level than a common insufflator. Therefore, high flow insufflators offer great advantages in maintaining intra-abdominal pressure and temperature in comparison to conventional insufflators and thus enhance laparoscopic bariatric surgery by potentially reducing the operating time and the undesirable effects of CO2 pneumoperitoneum.