Experimental study of delivery of humidified-warm carbon dioxide during open abdominal surgery

The role of warmed-humidified carbon dioxide insufflation in colorectal surgery: A systematic review and meta-analysis

BACKGROUND

Maintenance of normothermia is a crucial part of enhanced recovery after colorectal surgery. Dry-cold carbon dioxide (CO2 ) traditionally used for insufflation in laparoscopic surgery and negative pressure operating theatres has been associated with intraoperative hypothermia. Studies suggest that use of warmed-humidified CO2 may promote normothermia. However, due to a scarcity of high-quality studies demonstrating a proven benefit on intraoperative core body temperature, its use in colorectal surgery remains limited. Therefore, the aim of this review was to evaluate the effects of warmed-humidified CO2 compared to traditional dry-cold CO2 , or ambient air in operating theatres, during colorectal surgery.

METHODS

A search of Medline, EMBASE, and CENTRAL was performed. Randomised controlled trials (RCTs) that compared patients receiving warmed-humidified CO2 with either dry-cold CO2 insufflation in laparoscopic procedures or no insufflation during open surgery were included. The primary outcome was change in intraoperative core body temperature. Secondary outcomes included length of stay, operating time, return of gastrointestinal function, wound infection, and postoperative pain. A pairwise meta-analysis was performed using inverse variance random effects.

RESULTS

Among the six RCTs included, 208 patients received warmed-humidified CO2 (42.3% female, mean age: 65.8 years) and 210 patients received either dry-cold CO2 in laparoscopic procedures or no gas insufflation during open procedures (46.2% female, mean age: 66.1 years). No significant difference was found for change in intraoperative core body temperature (MD = 0.01, 95% CI: -0.1, 0.11, p = 0.90, very low certainty). Patients in the warmed-humidified CO2 group had significantly higher pain scores on postoperative day 1 (MD = 1.61, 95% CI: 0.91, 2.31, p < 0.05, very low certainty). No significant differences were found in any of the other secondary outcomes studied.

CONCLUSION

Patients undergoing colorectal surgery receiving warmed-humidified CO2 do not experience any clinically meaningful difference in core body temperature change compared to their counterparts receiving dry-cold CO2 insufflation or no insufflation. However, patients may report greater pain scores on postoperative day 1 with warmed-humidified CO2 . There is likely no clinically important difference between warmed-humidified CO2 and dry-cold CO2 for patients undergoing colorectal surgery. Patient, clinician, and institution factors should be considered when deciding between these two insufflation modalities.

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.

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-HuggerTM 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.

Warm humidified CO2 insufflation improves pericardial integrity for cardiac surgery: a randomized control study

BACKGROUND

Flooding the surgical field with dry cold CO<inf>2</inf> during open-chamber cardiac surgery has been used to mitigate air entrainment into the systemic circulation. However, exposing epithelial surfaces to cold, dry gas causes tissue desiccation. This randomized controlled study was designed to investigate whether the use of humidified warm CO<inf>2</inf> insufflation into the cardiac cavity could reduce pericardial tissue damage and the incidence of micro-emboli when compared to dry cold CO<inf>2</inf> insufflation.

METHODS

Forty adult patients requiring elective open-chamber cardiac surgery were randomized to have either dry cold CO<inf>2</inf> insufflation via a standard catheter or humidified warm CO<inf>2</inf> insufflation via the HumiGard device (Fisher & Paykel Healthcare, Panmure, Auckland, New Zealand). The primary endpoint was biopsied pericardial tissue damage, assessed using electron microscopy. We assessed the percentage of microvilli and mesothelial damage, using a damage severity score (DSS) system. We compared the proportion of patients who had less damage, defined as DSS<2. Secondary endpoints included the severity of micro-emboli, by visual assessment of bubble load on transesophageal echocardiogram; lowest near infrared spectroscopy; total de-airing time; highest cardio-pulmonary bypass sweep speed; hospital length of stay and complications.

RESULTS

A higher proportion of patients in the humidified warm CO<inf>2</inf> group displayed conserved microvilli (47% vs. 11%, P=0.03) and preserved mesothelium (42% vs. 5%, P=0.02) compared to the control group. There were no differences in the secondary outcomes.

CONCLUSIONS

Humidified warm CO<inf>2</inf> insufflation significantly reduced pericardial epithelial damage when compared to dry cold CO<inf>2</inf> insufflation in open-chamber cardiac surgery. Further studies are warranted to investigate its potential clinical benefits.

Risk factors for inadvertent intraoperative hypothermia in patients undergoing laparoscopic surgery: A prospective cohort study

Background

Inadvertent intraoperative hypothermia is frequent during open surgeries; however, few studies on hypothermia during laparoscopic abdominal surgery have been reported. We aimed to investigate the incidence and risk factors for hypothermia in patients undergoing laparoscopic abdominal surgery.

Methods

This single-center prospective cohort observational study involved patients undergoing laparoscopic surgery between October 2018 and June 2019. Data on core body temperature and potential variables were collected. A multivariate logistic regression analysis was performed to identify the risk factors associated with hypothermia. A Cox regression analysis was used to verify the sensitivity of the results.

Results

In total, 690 patients were included in the analysis, of whom 200 (29.0%, 95% CI: 26%−32%) had a core temperature < 36°C. The core temperature decreased over time, and the incident hypothermia increased gradually. In the multivariate logistic regression analysis, age (OR = 1.017, 95% CI: 1.000–1.034, P = 0.050), BMI (OR = 0.938, 95% CI: 0.880–1.000; P = 0.049), baseline body temperature (OR = 0.025, 95% CI: 0.010–0.060; P < 0.001), volume of irrigation fluids (OR = 1.001, 95% CI: 1.000–1.001, P = 0.001), volume of urine (OR = 1.001, 95% CI: 1.000–1.003, P = 0.070), and duration of surgery (OR = 1.010, 95% CI: 1.006–1.015, P < 0.001) were significantly associated with hypothermia. In the Cox analysis, variables in the final model were age, BMI, baseline body temperature, volume of irrigation fluids, blood loss, and duration of surgery.

Conclusions

Inadvertent intraoperative hypothermia is evident in patients undergoing laparoscopic surgeries. Age, BMI, baseline body temperature, volume of irrigation fluids, and duration of surgery are significantly associated with intraoperative hypothermia.

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.

Post-surgical adhesions are triggered by calcium-dependent membrane bridges between mesothelial surfaces

Surgical adhesions are bands of scar tissues that abnormally conjoin organ surfaces. Adhesions are a major cause of post-operative and dialysis-related complications, yet their patho-mechanism remains elusive, and prevention agents in clinical trials have thus far failed to achieve efficacy. Here, we uncover the adhesion initiation mechanism by coating beads with human mesothelial cells that normally line organ surfaces, and viewing them under adhesion stimuli. We document expansive membrane protrusions from mesothelia that tether beads with massive accompanying adherence forces. Membrane protrusions precede matrix deposition, and can transmit adhesion stimuli to healthy surfaces. We identify cytoskeletal effectors and calcium signaling as molecular triggers that initiate surgical adhesions. A single, localized dose targeting these early germinal events completely prevented adhesions in a preclinical mouse model, and in human assays. Our findings classifies the adhesion pathology as originating from mesothelial membrane bridges and offer a radically new therapeutic approach to treat adhesions.

Surgical adhesions are organ-joining bands of scar tissue that remain clinically untreatable. Here, the authors show that adhesions are formed through expansive mesothelial membrane bridges, and that blocking these with small molecules prevents formation of adhesions in mice.

Randomized clinical trial of the effect of intraoperative humidified carbon dioxide insufflation in open laparotomy for colorectal resection

BACKGROUND

Animal studies have shown that peritoneal injury can be minimized by insufflating the abdominal cavity with warm humidified carbon dioxide gas.

METHODS

A single-blind RCT was performed at a tertiary colorectal unit. Inclusion criteria were patient aged 18 years and over undergoing open elective surgery. The intervention group received warmed (37°C), humidified (98 per cent relative humidity) carbon dioxide (WHCO2  group). Multiple markers of peritoneal inflammation and oxidative damage were used to compare groups, including cytokines and chemokines, apoptosis, the 3-chlorotyrosine/native tyrosine ratio, and light microscopy on peritoneal biopsies at the start (T0 ) and end (Tend ) of the operation. Postoperative clinical outcomes were compared between the groups.

RESULTS

Of 40 patients enrolled, 20 in the WHCO2 group and 19 in the control group were available for analysis. A significant log(Tend /T0 ) difference between control and WHCO2 groups was documented for interleukin (IL) 2 (5·3 versus 2·8 respectively; P = 0·028) and IL-4 (3·5 versus 2·0; P = 0·041), whereas apoptosis assays documented no significant change in caspase activity, and similar apoptosis rates were documented along the peritoneal edge in both groups. The 3-chlorotyrosine/tyrosine ratio had increased at Tend by 1·1-fold in the WHCO2 group and by 3·1-fold in the control group. Under light microscopy, peritoneum was visible in 11 of 19 samples from the control group and in 19 of 20 samples from the WHCO2 group (P = 0·006). The only difference in clinical outcomes between intervention and control groups was the number of days to passage of flatus (2·5 versus 5·0 days respectively; P = 0·008).

CONCLUSION

The use of warmed, humidified carbon dioxide appears to reduce some markers related to peritoneal oxidative damage during laparotomy. No difference was observed in clinical outcomes, but the study was underpowered for analysis of surgical results. Registration number: NCT02975947 ( www.ClinicalTrials.gov/).

Modeling open surgery in mice to explore peritoneal damage, carbon dioxide humidification and desmoidogenesis

Background

The exposure of the peritoneum to desiccation during surgery generates lasting damage to the mesothelial lining which impacts inflammation and tissue repair. We have previously explored open abdominal surgery in mice subjected to passive airflow however, operating theatres employ active airflow. Therefore, we sought an engineering solution to recapitulate the active airflow in mice. Similarly, to the passive airflow studies we investigated the influence of humidified-warm carbon dioxide (CO₂) on this damage in the context of active airflow. Additionally, we addressed the controversial role of surgery in exacerbating desmoidogenesis in a mouse model of familial adenomatous polyposis.

Methods

An active airflow mouse-operating module manufactured to produce the equivalent downdraft airflow to that of a modern operating theatre was employed. We quantified mesothelial cell integrity by scanning electron microscopy (SEM) sampled from the peritoneal wall that was subjected to mechanical damage or not, with and without the delivery of humidified-warm CO₂. To explore the role of open and laparoscopic surgery in the process of desmoidogenesis we crossed Apc^min/+ C57Bl/6 mice with p53^+/− mice to generate animals that developed desmoid tumors with 100% penetrance.

Results

One hour of active airflow generates substantial damage to peritoneal mesothelial cells and their microvilli as measured at 24 h post intervention, which is significantly greater than that generated by passive airflow. Use of humidified-warm CO₂ mostly protects the mesothelium that had not experienced additional mechanical (surgical) damage at 24 h. Maximal damage was evident in all treatment groups regardless of flow or use of gas. At day 10 mechanically-damaged peritoneum remains in mice but is essentially repaired in the gas-treated groups. Regarding desmoidogenesis, operating procedures did not increase the frequency of desmoid tumors but their frequency correlated with time following surgery but not age of mice.

Conclusions

Active airflow generates more peritoneal damage than passive airflow and is reduced significantly by the use of humidified-warm CO₂. Introduced peritoneal damage is largely repaired in mice by day 10 with gas. Desmoid tumor incidence is not increased substantially by surgery itself but rises over time following surgery compared to non-surgery mice.

Clinical effects of warmed humidified carbon dioxide insufflation in infants undergoing major laparoscopic surgery

PURPOSE

Some studies have reported that warmed humidified carbon dioxide (CO2) insufflation in adult laparoscopic surgery could reduce pain and improve the core body temperature (CBT). However, similar studies are lacking in infants. Thus, this study aimed to investigate the clinical effects of warmed, humidified CO2 insufflation in pediatric patients undergoing major laparoscopic surgeries.

METHODS

From January 2015 to December 2017, infants who underwent major laparoscopic surgeries in Ningbo Women and Children's Hospital were randomized to Group A (standard CO2 insufflation) or Group B (warmed humidified CO2 insufflation, 35°C, 95% relative humidity). Change in CBT at the end of surgery was the primary outcome. Secondary outcomes included surgery time, intraoperative blood loss, oxygen saturation (SO2), and Face, Legs, Activity, Cry and Consolability (FLACC) scale. These variables were compared between the 2 groups.

RESULTS

Sixty-three infants (38 females, 25 males) were included; 30 patients were in Group A and 33 in Group B. The diseases treated with the laparoscopic approach included congenital megacolon, congenital diaphragmatic hernia, and intestinal malrotation. No deaths were noted. CBT was significantly higher in Group B at the end of surgery (P = .021). The occurrence of postoperative shivering (P = .02), hypothermia (P = .032), bowel movement (P = .044), and hospital stay (P = .038) was significantly different between the 2 groups; Group B had less shivering and hypothermia occurrence after surgery. Moreover, Group B demonstrated a more rapid postoperative recovery of bowel movement and shortened hospital stay than Group A. There was no statistical difference in operative time (P = .162), intraoperative blood loss (P = .541), SO2 (P = .59), and FLACC scale (P = .65) between the 2 groups.

CONCLUSION

The use of warmed humidified CO2 insufflation in infants undergoing major laparoscopic surgery was helpful for maintaining normothermia and was associated with several positive postoperative outcomes, including less shivering and hypothermia, faster recovery of bowel movement, and shortened hospital stay.