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

A multi-center study to predict the risk of intraoperative hypothermia in gynecological surgery patients using preoperative variables

OBJECTIVES

Hypothermia is highly common in patients undergoing gynecological surgeries under general anesthesia, so the length of hospitalization and even the risk of mortality are substantially increased. Our aim was to develop a simple and practical model to preoperatively identify gynecological surgery patients at risk of intraoperative hypothermia.

METHODS

In this retrospective study, we collected data from 802 patients who underwent gynecological surgery at three medical centers from June 2022 to August 2023. We further allocated the patients to a training group, an internal validation group, or an external validation group. The preliminary predictive factors for intraoperative hypothermia in gynecological patients were determined using the least absolute shrinkage and selection operator (LASSO) method. The final predictive factors were subsequently identified through multivariate logistic regression analysis, and a nomogram for predicting the occurrence of hypothermia was established.

RESULTS

A total of 802 patients were included, with 314 patients in the training cohort (mean age 48.5 ± 12.6 years), 130 patients in the internal validation cohort (mean age 49.9 ± 12.5 years), and 358 patients in the external validation cohort (mean age 47.6 ± 14.0 years). LASSO regression and multivariate logistic regression analyses indicated that body mass index, minimally invasive surgery, baseline heart rate, baseline body temperature, history of previous surgery, and aspartate aminotransferase level were associated with intraoperative hypothermia in gynecological surgery patients. This nomogram was constructed based on these six variables, with a C-index of 0.712 for the training cohort.

CONCLUSIONS

We established a practical predictive model that can be used to preoperatively predict the occurrence of hypothermia in gynecological surgery patients.

CLINICAL TRIAL REGISTRATION

chictr.org.cn, identifier ChiCTR2300071859.

Impact of warm saline irrigation, hyperthermic intraperitoneal chemotherapy on postoperative pain in primary ovarian cancer from the KOV-HIPEC-01 randomized trial

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) has emerged as a treatment option at the time of cytoreductive surgery after neoadjuvant chemotherapy. The effect of active warming of HIPEC on postoperative pain needs to be investigated. This study aimed to investigate whether HIPEC reduces postoperative pain.

METHODS

From the KOV-HIPEC-01 trial, a randomized controlled trial of HIPEC for advanced primary ovarian cancer, 184 patients with a residual tumor size <1 cm were randomly assigned to the HIPEC and control groups at a 1:1 ratio. The consumption of analgesics and pain scales were analyzed. Hyperthermic intraperitoneal chemotherapy was administered after cytoreductive surgery. The primary objective was to compare the consumption of opioids measured in morphine milligram equivalents and non-opioids measured as the maximum daily dose between the HIPEC and control groups. The secondary objective was to compare the minimum and maximum pain intensities on numeric rating scales between the two groups using a linear mixed model.

RESULTS

Lesser consumption of non-opioids, with a lower mean maximum daily dose on postoperative days 1 and 2, was observed. The HIPEC group also experienced lower maximum pain intensities on postoperative day 1. No overall differences in the minimum or maximum pain intensities were observed on postoperative day 7.

CONCLUSION

The addition of HIPEC to cytoreductive surgery did not lead to increased postoperative pain, as demonstrated by a reduction in the use of analgesics and lower scores on postoperative pain scales during the early postoperative period.

The effect of warm and humidified gas insufflation in gynecological laparoscopy on maintenance of body temperature: a prospective randomized controlled multi-arm trial

Background

Hypothermia is defined as a decrease in body core temperature to below 36 °C. If intraoperative heat-preserving measures are omitted, a patient’s temperature will fall by 1 – 2 °C. Even mild forms of intraoperative hypothermia can lead to a marked increase in morbidity and mortality. Using warm and humidified gas insufflation in laparoscopy may help in the maintenance of intraoperative body temperature.

Methods

In this prospective randomized controlled study, we investigated effects of temperature and humidity of the insufflation gas on intra- and postoperative temperature management. 150 patients undergoing gynecologic laparoscopic surgery were randomly assigned to either insufflation with non-warmed, non-humidified CO₂ with forced air warming blanket (AIR), humidified warm gas without forced air warming blanket (HUMI) or humidified warm gas combined with forced air warming blanket (HUMI+). We hypothesized that the use of warmed laparoscopic gas would have benefits in the maintenance of body temperature and reduce the occurrence of hypothermia.

Results

The use of warm and humidified gas insufflation alone led to more hypothermia episodes with longer duration and longer recovery times as well as significantly lower core body temperature compared to the other two groups. In the comparison of the AIR group and HUMI + group, HUMI + patients had a significantly higher body temperature at arrival at the PACU (Post Anaesthesia Care Unit), had the least occurrence of hypothermia and suffered from less shivering.

Conclusion

The use of warm and humidified gas insufflation alone does not sufficiently warm the patients. The optimal temperature management is achieved in the combination of external forced air warming and insufflation of warm and humidified laparoscopy gas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00404-022-06499-z.

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.

Time Characteristics of Shoulder Pain after Laparoscopic Surgery

Objective:

To explore the time characteristics of shoulder pain after laparoscopic gynecological operation.

Methods:

We conducted prospective clinical observations and literature review. We studied 442 cases of laparoscopic gynecological surgery. We used a visual analogue scale to evaluate the pain of patients at different time points after operation. We searched the English literature of shoulder pain after gynecological laparoscopic surgery. The observation time points of these studies included 12–24 hours or the first day after surgery, and at least one time point before this time point.

Results:

The total incidence of shoulder pain was 68%. More than 90% of patients begin to feel shoulder pain on the first day after surgery, not on the day of surgery. 26 articles observed the severity of postlaparoscopic shoulder pain (PLSP) at different time points, of which 17 articles found that the intensity of the shoulder pain peaked at 12–24 hours or the first day after operation.

Discussion:

The occurrence of PLSP presents obvious time characteristics. The incidence and severity of PLSP peaked on the first day or 12–24 hours after operation. To prevent and treat PLSP better, clinicians should make a more in-depth study according to the time characteristics of PLSP.

The risk of shoulder pain after laparoscopic surgery for infertility is higher in thin patients

Postlaparoscopic shoulder pain (PLSP) is a common clinical problem that needs to be addressed by medical professionals who are currently perform laparoscopic surgeries. The purpose of this study was to determine the perioperative clinical factors and demographic characteristics associated with PLSP. A prospective observational study was performed with 442 inpatients undergoing laparoscopic surgery for infertility. The pain visual analogue scale was used as the measuring instrument. To identify the predictors of PLSP, we performed multivariate conditional logistic regression. PLSP was correlated with body mass index (BMI, odds ratio = 0.815). The incidence of shoulder pain and more severe shoulder pain in patients with a lower BMI was significantly higher than it was in patients with a higher BMI, and BMI was significantly negatively correlated with PLSP. Most of the patients (95%) began to experience shoulder pain on the first postoperative day, and it rarely occurred on the day of surgery. Patients with lower BMI presented a higher risk of reporting shoulder pain on the first postoperative day. We should identify high-risk patients in advance and make specific treatment plans according to the characteristics of their symptoms.

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.

Prevention of Intraoperative Hypothermia in Laparoscopy by the Use of Body-Temperature and Humidified CO 2 : a Pilot Study

Introduction Hypothermia is defined as a decrease in body core temperature to below 36 °C. If intraoperative heat-preserving measures are omitted, a patient's temperature will fall by 1 - 2 °C. Even mild forms of intraoperative hypothermia can lead to a marked increase in morbidity and mortality. The temperature of the insufflation gas is usually disregarded in the treatment and prevention of hypothermia. This study was conducted to investigate the effect of body-temperature and humidified CO ₂ on the intraoperative temperature profile and avoidance of hypothermia in laparoscopic surgery. Material and Methods In this retrospective, non-randomised case control study, 110 patients whose planned operation lasted at least 60 minutes were identified from 376 patients by means of an algorithm. Dry (20% humidity) CO ₂ at room temperature was insufflated in 51 patients (control group). 59 patients were insufflated with humidified (98% humidity) CO ₂ at body temperature (37 °C) (study group). These conditions were achieved with the HumiGard MR860 Surgical Humidification System (Fisher & Paykel Healthcare Limited, Auckland, New Zealand). The intraoperative temperature profile was evaluated by measurements every 10 minutes. Statistical analysis was performed with IBM ^® SPSS ^® Statistics 23.0.0. Results The intraoperative temperature in the control group fell steadily, while a continuous rise in temperature was observed in the study group. Warming was demonstrated in the study group with a start-end temperature difference of 0.09 °C, which differed significantly from the control group, in which it was - 0.09 °C (p = 0.011). The middle-end difference of 0.11 °C showed even higher significance in favour of the warmed gas (p = 0.003). The rate of hypothermia at the start of the operation fell from 50 to 36% in the study group and increased from 36 to 42% in the control group. Conclusion These results show that the use of body-temperature and humidified insufflation gas for laparoscopy can help to prevent intraoperative hypothermia.

Morpheus and the Underworld-Interventions to Reduce the Risks of Opioid Use After Surgery: ORADEs, Dependence, Cancer Progression, and Anastomotic Leakage

BACKGROUND

Perioperative pain management is a key element of enhanced recovery after surgery (ERAS) programs. A multimodal approach to analgesia as part of a coordinated ERAS includes the reduction of opioid use. This review aims to discuss opioid-related adverse events, strategies to reduce opioid use after surgery, and the relevance to the present "opioid crisis" in North America.

METHODS

A literature review of the pharmacology of opioid drugs, perioperative opioid reduction strategies, and the potential public health benefit was performed. This included current ERAS guidelines on multimodal analgesia, randomized controlled trials on perioperative analgesia, and intervention studies to decrease opioid use, misuse, and diversion in North America.

RESULTS

Reduction of perioperative opioid usage has been endorsed by joint clinical practice guidelines on the management of postoperative pain from the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists. Interventions as part of an "opioid bundle" that can be incorporated into ERAS protocols include multimodal analgesia, regional anesthesia, opioid sparing drugs, carbon dioxide humidification during laparoscopy, changing opioid prescription practices, patient and physician education, and proper disposal of unused opioid medications.

CONCLUSION

There are substantial benefits in incorporating opioid reduction strategies into ERAS and clinical practice guidelines. These include faster return of function and mobility, and decreased opioid-related adverse drug events (ORADEs), postoperative morbidity and mortality, and length of hospital stay. Improved oncological outcomes after cancer surgery may be an additional benefit. Evidence-based interventions can also reduce opioid abuse and diversion in the community.

Pain management after laparoscopic hysterectomy: systematic review of literature and PROSPECT recommendations

Background and objectives

Laparoscopic hysterectomy is increasingly performed because it is associated with less postoperative pain and earlier recovery as compared with open abdominal hysterectomy. The aim of this systematic review was to evaluate the available literature regarding the management of pain after laparoscopic hysterectomy.

Strategy and selection criteria

Randomized controlled trials evaluating postoperative pain after laparoscopic hysterectomy published between January 1996 and May 2018 were retrieved, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, from the EMBASE and MEDLINE databases and the Cochrane Register of Controlled Trials. Efficacy and adverse effects of analgesic techniques were assessed.

Results

Of the 281 studies initially identified, 56 were included. Of these, 31 assessed analgesic or anesthetic interventions and 25 assessed surgical interventions. Acetaminophen, non-steroidal anti-inflammatory drugs, and dexamethasone reduced opioid consumption. Limited evidence hindered recommendations on alpha-2-agonists. Inconsistent evidence was found in the studies investigating pregabalin and transversus abdominis plane block, and no evidence was found for intraperitoneal local anesthetics, port site infiltration, or single-port laparoscopy. Measures to lower peritoneal insufflation pressure or humidify or heat insufflated gas seem to reduce the incidence of shoulder pain, but not abdominal pain.

Conclusions

The baseline analgesic regimen for laparoscopic hysterectomy should include acetaminophen, a non-steroidal anti-inflammatory drug, dexamethasone, and opioids as rescue analgesics.

Interventions to reduce shoulder pain following gynaecological laparoscopic procedures

BACKGROUND

Laparoscopy is a common procedure used to diagnose and treat various gynaecological conditions. Shoulder-tip pain (STP) as a result of the laparoscopy occurs in up to 80% of women, with potential for significant morbidity, delayed discharge and readmission. Interventions at the time of gynaecological laparoscopy have been developed in an attempt to reduce the incidence and severity of STP.

OBJECTIVES

To determine the effectiveness and safety of methods for reducing the incidence and severity of shoulder-tip pain (STP) following gynaecological laparoscopy.

SEARCH METHODS

We searched the following databases: Cochrane Gynaecology and Fertility (CGF) Specialised Register, the Cochrane Central Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO and CINAHL from inception to 8 August 2018. We also searched the reference lists of relevant articles and registers of ongoing trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of interventions used during or immediately after gynaecological laparoscopy to reduce the incidence or severity of STP.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Primary outcomes: incidence or severity of STP and adverse events of the interventions; secondary outcomes: analgesia usage, delay in discharge, readmission rates, quality-of-life scores and healthcare costs.

MAIN RESULTS

We included 32 studies (3284 women). Laparoscopic procedures in these studies varied from diagnostic procedures to complex operations. The quality of the evidence ranged from very low to moderate. The main limitations were risk of bias, imprecision and inconsistency.Specific technique versus "standard" technique for releasing the pneumoperitoneumUse of a specific technique of releasing the pneumoperitoneum (pulmonary recruitment manoeuvre, extended assisted ventilation or actively aspirating intra-abdominal gas) reduced the severity of STP at 24 hours (standardised mean difference (SMD) -0.66, 95% confidence interval (CI) -0.82 to -0.50; 5 RCTs; 670 participants; I² = 0%, low-quality evidence) and reduced analgesia usage (SMD -0.53, 95% CI -0.70 to -0.35; 4 RCTs; 570 participants; I² = 91%, low-quality evidence). There appeared to be little or no difference in the incidence of STP at 24 hours (odds ratio (OR) 0.87, 95% CI 0.41 to 1.82; 1 RCT; 118 participants; low-quality evidence).No adverse events occurred in the only study assessing this outcome.Fluid instillation versus no fluid instillationFluid instillation is probably associated with a reduction in STP incidence (OR 0.38, 95% CI 0.22 to 0.66; 2 RCTs; 220 participants; I² = 0%, moderate-quality evidence) and severity (mean difference (MD) (0 to 10 visual analogue scale (VAS) scale) -2.27, 95% CI -3.06 to -1.48; 2 RCTs; 220 participants; I² = 29%, moderate-quality evidence) at 24 hours, and may reduce analgesia usage (MD -12.02, 95% CI -23.97 to -0.06; 2 RCTs; 205 participants, low-quality evidence).No study measured adverse events.Intraperitoneal drain versus no intraperitoneal drainUsing an intraperitoneal drain may reduce the incidence of STP at 24 hours (OR 0.30, 95% CI 0.20 to 0.46; 3 RCTs; 417 participants; I² = 90%, low-quality evidence) and may reduce analgesia use within 48 hours post-operatively (SMD -1.84, 95% CI -2.14 to -1.54; 2 RCTs; 253 participants; I² = 90%). We are uncertain whether it reduces the severity of STP at 24 hours, as the evidence was very low quality (MD (0 to 10 VAS scale) -1.85, 95% CI -2.15 to -1.55; 3 RCTs; 320 participants; I² = 70%).No study measured adverse events.Subdiaphragmatic intraperitoneal local anaesthetic versus control (no fluid instillation, normal saline or Ringer's lactate)There is probably little or no difference between the groups in incidence of STP (OR 0.72, 95% CI 0.42 to 1.23; 4 RCTs; 336 participants; I² = 0%; moderate-quality evidence) and there may be no difference in STP severity (MD -1.13, 95% CI -2.52 to 0.26; 1 RCT; 50 participants; low-quality evidence), both measured at 24 hours. However, the intervention may reduce post-operative analgesia use (SMD-0.57, 95% CI -0.94 to -0.21; 2 RCTs; 129 participants; I² = 51%, low-quality evidence).No adverse events occurred in any study.Local anaesthetic into peritoneal cavity (not subdiaphragmatic) versus normal salineLocal anaesthetic into the peritoneal cavity may reduce the incidence of STP at 4 to 8 hours post-operatively (OR 0.23, 95% CI 0.06 to 0.93; 2 RCTs; 157 participants; I² = 56%; low-quality evidence). Our other outcomes of interest were not assessed.Warmed, or warmed and humidified CO₂ versus unwarmed and unhumidified CO₂There may be no difference between these interventions in incidence of STP at 24 to 48 hours (OR 0.81 95% CI 0.45 to 1.49; 2 RCTs; 194 participants; I² = 12%; low-quality evidence) or in analgesia usage within 48 hours (MD -4.97 mg morphine, 95% CI -11.25 to 1.31; 1 RCT; 95 participants; low-quality evidence); there is probably little or no difference in STP severity at 24 hours (MD (0 to 10 VAS scale) 0.11, 95% CI -0.75 to 0.97; 2 RCTs; 157 participants; I² = 50%; moderate-quality evidence).No study measured adverse events.Gasless laparoscopy versus CO₂ insufflationGasless laparoscopy may be associated with increased severity of STP within 72 hours post-operatively when compared with standard treatment (MD 3.8 (0 to 30 VAS scale), 95% CI 0.76 to 6.84; 1 RCT; 54 participants, low-quality evidence), and there may be no difference in the risk of adverse events (OR 2.56, 95% CI 0.25 to 26.28; 1 RCT; 54 participants; low-quality evidence).No study measured the incidence of STP.

AUTHORS' CONCLUSIONS

There is low to moderate-quality evidence that the following interventions are associated with a reduction in the incidence or severity, or both, of STP, or a reduction in analgesia requirements for women undergoing gynaecological laparoscopy: a specific technique for releasing the pneumoperitoneum; intraperitoneal fluid instillation; an intraperitoneal drain; and local anaesthetic applied to the peritoneal cavity (not subdiaphragmatic).There is low to moderate-quality evidence that subdiaphragmatic intraperitoneal local anaesthetic and warmed and humidified insufflating gas may not make a difference to the incidence or severity of STP.There is low-quality evidence that gasless laparoscopy may increase the severity of STP, compared with standard treatment.Few studies reported data on adverse events. Some potentially useful interventions have not been studied by RCTs of gynaecological laparoscopy.

Effects of Intraoperative Insufflation With Warmed, Humidified CO2 during Abdominal Surgery: A Review

PURPOSE

During a laparotomy, the peritoneum is exposed to the cold, dry ambient air of the operating room (20°C, 0%-5% relative humidity). The aim of this review is to determine whether the use of humidified and/or warmed CO2 in the intraperitoneal environment during open or laparoscopic operations influences postoperative outcomes.

METHODS

A review was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, OVID MEDLINE, Cochrane Central Register of Controlled Trials and Embase databases were searched for articles published between 1980 and 2016 (October). Comparative studies on humans or nonhuman animals that involved randomized controlled trials (RCTs) or prospective cohort studies were included. Both laparotomy and laparoscopic studies were included. The primary outcomes identified were peritoneal inflammation, core body temperature, and postoperative pain.

RESULTS

The literature search identified 37 articles for analysis, including 30 RCTs, 7 prospective cohort studies, 23 human studies, and 14 animal studies. Four studies found that compared with warmed/humidified CO2, cold, dry CO2 resulted in significant peritoneal injury, with greater lymphocytic infiltration, higher proinflammatory cytokine levels and peritoneal adhesion formation. Seven of 15 human RCTs reported a significantly higher core body temperature in the warmed, humidified CO2 group than in the cold, dry CO2 group. Seven human RCTs found lower postoperative pain with the use of humidified, warmed CO2.

CONCLUSION

While evidence supporting the benefits of using humidified and warmed CO2 can be found in the literature, a large human RCT is required to validate these findings.

Reduction in surgical fog with a warm humidified gas management protocol significantly shortens procedure time in pediatric robot-assisted laparoscopic procedures

INTRODUCTION

The adoption of robot-assisted laparoscopic (RAL) procedures in the field of urology has occurred rapidly, but is, to date, without pediatric-specific instrumentation. Surgical fog is a significant barrier to safe and efficient laparoscopy. This appears to be a significant challenge when adapting three-dimensional 8.5-mm scopes to use in pediatric RAL surgery. The objective of the present study was to compare matched controls from a prospectively collected database to procedures that were performed utilizing special equipment and a protocol to minimize surgical fog in pediatric RAL procedures.

METHODS

A prospectively collected database of all patients who underwent RAL pediatric urology procedures was used to compare: procedure, age, sex, American Society of Anesthesiologists score, weight, console time, number of times the camera was removed to clean the lens during a procedure, length of hospital stay, and morphine equivalents required in the postoperative period. A uniquely developed protocol was used, it consisted of humidified (95% relative humidity) and warmed CO₂ gas (95 °F) insufflation via Insuflow® on a working trocar, with active smoke evacuation via PneuVIEW®XE on the opposite working trocar with a gas pass through of 3.5-5 l/min. The outcomes were compared with matched controls (Summary Fig).

RESULTS

The novel gas protocol was utilized in 13 procedures (five pyeloplasties, two revision pyeloplasties, three ureteroureterostomies (UU), three nephrectomies) and compared with 13 procedures (six pyeloplasties, one revision pyeloplasty, three UU, three nephrectomies) prior to the protocol development. There was no statistical difference in age (P = 0.78), sex (P = 0.11), ASA score (P = 1.00) or weight (P = 0.69). There were no open conversions, ≥Grade 2 Clavien complications, or readmissions within 30 days in either group.

CONCLUSIONS

This novel gas protocol yielded a statistically significant reduction in procedure time, by decreasing the number of times the camera was required to be pulled during the case by more than five occurrences, and saved approximately 35 min on average per case.

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.

Warm and Humidified Versus Cold and Dry CO2 Pneumoperitoneum in Minimally Invasive Colon Resection: A Randomized Controlled Trial

INTRODUCTION

Peritoneal insufflation with warm-humidified (WH) CO₂ gas during minimally invasive surgical procedures is purported to prevent hypothermia and peritoneal desiccation and is associated with decreased postoperative IL-6 levels. This randomized study's purpose was to determine the clinical impact of WH versus cold-dry (CD) CO₂ in minimally invasive colon resection (MICR), and to assess perioperative plasma levels of IL-6, TIMP-1, sVEGF-R1, and HSP-70 after MICR.

METHODS

Operative and short-term clinical data plus perioperative blood samples were collected on MICR patients randomized to receive either WH (36.7°C, 95% humidity) or CD (room temperature, 0% humidity) CO₂ perioperatively. Peritoneal biopsies were taken at the start and end of surgery. Outcomes tracked included core temperature, postoperative in-hospital pain levels, analgesia requirements, and standard recovery parameters. Preoperative and postoperative days (PODs) 1 and 3 plasma protein levels were determined via ELISA.

RESULTS

A total of 101 patients were randomized to WH CO₂ (50) or CD CO₂ (51). The WH group contained more diabetics ( P = .03). There were no differences in indication, minimally invasive surgical method used, or core temperature. Pain scores were similar; however, the WH patients required less narcotics on PODs 1 to 3 ( P < .05), and less ketorolac on PODs 1 and 2 ( P < .03). No differences in length of stay, complication rates, or time to flatus/diet tolerance were noted. Plasma levels of the 4 proteins were similar postoperatively. Though insignificant, the WH group had less marked histologic changes on "end-of-case" peritoneal biopsies.

CONCLUSION

This study found significantly lower pain medication requirements for PODs 1 to 3 for the WH group; however, because there were no differences in the pains scores between the groups, firm conclusions regarding WH CO₂ cannot be made.

Warmed, humidified CO2 insufflation benefits intraoperative core temperature during laparoscopic surgery: A meta-analysis

BACKGROUND

Intraoperative hypothermia is linked to postoperative adverse events. The use of warmed, humidified CO₂ to establish pneumoperitoneum during laparoscopy has been associated with reduced incidence of intraoperative hypothermia. However, the small number and variable quality of published studies have caused uncertainty about the potential benefit of this therapy. This meta-analysis was conducted to specifically evaluate the effects of warmed, humidified CO₂ during laparoscopy.

METHODS

An electronic database search identified randomized controlled trials performed on adults who underwent laparoscopic abdominal surgery under general anesthesia with either warmed, humidified CO₂ or cold, dry CO₂ . The main outcome measure of interest was change in intraoperative core body temperature.

RESULTS

The database search identified 320 studies as potentially relevant, and of these, 13 met the inclusion criteria and were included in the analysis. During laparoscopic surgery, use of warmed, humidified CO₂ is associated with a significant increase in intraoperative core temperature (mean temperature change, 0.3°C), when compared with cold, dry CO₂ insufflation_. CONCLUSION: Warmed, humidified CO₂ insufflation during laparoscopic abdominal surgery has been demonstrated to improve intraoperative maintenance of normothermia when compared with cold, dry CO_2.

Changes in the coelomic microclimate during carbon dioxide laparoscopy: morphological and functional implications

In this article the adverse effects of laparoscopic CO2 pneumoperitoneum and coelomic climate change, and their potential prevention by warmed, humidified carbon dioxide insufflation are reviewed. The use of pressurized cold, dry carbon dioxide (C02) pneumoperitoneum causes a number of local effects on the peritoneal mesothelium, as well as systemic effects. These can be observed at a macroscopic, microscopic, cellular and metabolic level. Local effects include evaporative cooling, oxidative stress, desiccation of mesothelium, disruption of mesothelial cell junctions and glycocalyx, diminished scavenging of reactive oxygen species, decreased peritoneal blood flow, peritoneal acidosis, peritoneal hypoxia or necrosis, exposure of the basal lamina and extracellular matrix, lymphocyte infiltration, and generation of peritoneal cytokines such as IL-1, IL-6, IL-8 and TNFα. Such damage is increased by high CO2 insufflation pressures and gas velocities and prolonged laparoscopic procedures. The resulting disruption of the glycocalyx, mesothelial cell barrier and exposure of the extracellular matrix creates a cascade of immunological and pro-inflammatory events and favours tumour cell implantation. Systemic effects include cardiopulmonary and respiratory changes, hypothermia and acidosis. Such coelomic climate change can be prevented by the use of lower insufflation pressures and preconditioned warm humidified CO2. By achieving a more physiological temperature, pressure and humidity, the coelomic microenvironment can be better preserved during pneumoperitoneum. This has the potential clinical benefits of maintaining isothermia and perfusion, reducing postoperative pain, preventing adhesions and inhibiting cancer cell implantation in laparoscopic surgery.

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.