Warming and humidification of insufflation carbon dioxide in laparoscopic colonic surgery: a double-blinded randomized controlled trial. Heated and humidified insufflation during laparoscopic gastric bypass surgery: effect on temperature, postoperative pain, and recovery outcomes. Prospective randomized trial of heated humidified versus cold dry carbon dioxide insufflation during laparoscopic gastric bypass. A randomized controlled trial assessing the benefit of humidified insufflation gas during laparoscopic surgery. The clinical impact of warmed insufflation carbon dioxide gas for laparoscopic cholecystectomy. Double-blind, prospective, randomized study of warmed, humidified carbon dioxide insufflation vs standard carbon dioxide for patients undergoing laparoscopic cholecystectomy. Effect of heated and humidified carbon dioxide gas on core temperature and postoperative pain: a randomized trial. Beneficial effects of humidified, warmed carbon dioxide insufflation during laparoscopic bariatric surgery: a randomized clinical trial. The effect of heated humidified carbon dioxide on postoperative pain, core temperature, and recovery times in patients having laparoscopic surgery: a randomized controlled trial.
We aimed to test the hypothesis that warming and humidification of insufflation CO2 would lead to reduced postoperative pain and improved recovery by reducing peritoneal inflammation in laparoscopic colonic surgery.
                Warming and humidification of insufflation gas is thought be beneficial in laparoscopic surgery, but evidence in prolonged laparoscopic procedures is lacking.
                We used a multicenter, double-blinded, randomized controlled design. The Study Group received warmed (37 degrees C), humidified (98% RH) insufflation carbon dioxide, and the Control Group received standard gas (19 degrees C, 0% RH). Anesthesia and analgesia were standardized. Intraoperative oesophageal temperature was measured at 15 minutes intervals. At the conclusion of surgery, the primary surgeon was asked to rate camera fogging on a Likert scale. Postoperative opiate usage was determined using Morphine Equivalent Daily Dose (MEDD), and pain was measured using visual analogue scores. Peritoneal and plasma cytokine concentrations were measured at 20 hours postoperatively. Postoperative recovery was measured using defined discharge and complication criteria, and the Surgical Recovery Score.
                Eighty-two patients were randomized, with 41 in each arm. Groups were well matched at baseline. Intraoperative core temperature was similar in both groups. Median camera fogging score was significantly worse in the Study group (4 vs. 2, P = 0.040). There were marginal differences in pain scores, but no significant differences were detected in MEDD usage, cytokine concentrations, or any recovery parameters measured.
                Warming and humidification of insufflation CO2 does not attenuate the early inflammatory cytokine response, and confers no clinically significant benefit in laparoscopic colonic surgery. Controversy exists regarding the efficacy of heated and humidified intraperitoneal gases in maintaining core body temperature. We performed a sham-controlled study to test the hypothesis that active warming and humidification of the insufflation gas reduces intraoperative heat loss and improves recovery outcomes.
                Fifty morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass procedures using a standardized anesthetic technique were randomly assigned to either a control (sham) group receiving room temperature insufflation gases with an inactive Insuflow (Lexion Medical, St. Paul, MN) device, or an active (Insuflow) group receiving warmed and humidified intraperitoneal gases. Esophageal and/or tympanic membrane temperature was measured perioperatively. Postoperative pain was assessed at 15 minute intervals using an 11-point verbal rating scale, with 0 = none to 10 = maximal. In addition, postoperative opioid requirements, incidence of nausea and vomiting, as well as the quality of recovery, were recorded.
                Use of the active Insuflow device was associated with significantly higher mean +/- standard deviation (SD) intraoperative core body temperatures (35.5 +/- 0.5 vs. 35.0 +/- 0.4 degrees C). Postoperative shivering (0 vs. 19%) and the requirement for morphine in the postanesthesia care unit (5 +/- 4 vs. 10 +/- 5 mg) were both significantly lower in the Insuflow vs. control groups. Patients in the Insuflow group also reported a higher quality of recovery 48 hours after surgery (15 vs. 13, P < 0.05).
                The Insuflow device modestly reduced shivering and heat loss, as well as the need for opioid analgesics in the early postoperative period. However, it failed to improve laparoscopic visualization due to fogging, and provided improvement in the quality of recovery only on postoperative day 2. The replacement of cold dry carbon dioxide with heated humidified gas for insufflation during complex laparoscopic procedures has been reported to decrease hypothermia and peritoneal cell desiccation, with a resultant decrease in postoperative pain and narcotic use and a shortened recovery, but may prevent the paralysis of the peritoneal polymorphonuclear cell cytokine cascade and add to the cost of the procedure. We report our outcomes comparing carbon dioxide insufflation with different characteristics during laparoscopic gastric bypass.
                Fifty consecutive patients were randomized to undergo laparoscopic gastric bypass with either cold-dry or heated-humidified carbon dioxide insufflation. Statistical analysis of variance between groups was determined by Levine's t test with the Greenhouse-Geisser correction, at a significance level of P <.05.
                The two groups were similar for preoperative gender, age, weight, body mass index, and baseline C-reactive protein. The intraoperative room and patient core temperature, liters of insufflation used, lens cleanings, operating time, recovery room time, and narcotics used were not significantly different. The postoperative subjective analog shoulder pain score was significantly less (P = .025) for the heated-humidified group at 18 hours, but not at 6, 12, 24, or 48 hours. The abdominal pain scores and overall narcotic use, postoperative C-reactive protein, and length of stay were not significantly different between the two groups.
                Heated-humidified insufflation resulted in a transient reduction in subjective shoulder pain at 18 hours postoperatively, but no reduction in abdominal pain or narcotics used. We were unable to verify any clinically significant difference between the two groups comparing heated-humidified and cold-dry insufflation after laparoscopic gastric bypass. We conducted a randomized controlled trial during laparoscopic cholecystectomy to determine the extent of heat preservation and postoperative pain reduction using humidified carbon dioxide (CO2) gas insufflation instead of standard dry insufflation gas.
                Forty consecutive patients were randomized. Twenty patients received humidified CO2, and 20 control patients received standard CO2 insufflation. A sample of 16 patients from each group was evaluated for postoperative pain levels.
                No adverse effects from the humidification of insufflated gas were observed. There was no significant difference in core body temperature between the two groups for this brief operation. Pain, as assessed by the Analogue Pain Score (APS) was significantly less for the group with humidified gas insufflation than for the control group at 6 h postoperatively as well as on the 1st, 2nd, and 3rd postoperative day and at follow-up 10 days after the operation. In the humidified group, the mean time to return to normal activities was significantly less-5.9 days, as compared to 10.9 days in the control group.
                The use of humidified insufflation gas reduces postoperative pain following laparoscopic cholecystectomy, but except for these relatively brief procedures, the heat-preserving effect of humidified gas insufflation is not significant. Reports suggest that the insufflation of cold gas to produce a pneumoperitoneum for laparoscopic surgery can lead to an intraoperative decrease in core body temperature and increased postoperative pain.
                In a randomized controlled trial with 20 patients undergoing laparoscopic cholecystectomy, the effect of insufflation using carbon dioxide gas warmed to 37 degrees C (group W) was compared with insufflation using room-temperature cold (21 degrees C) gas (group C). Intraoperative body core and intra-abdominal temperatures were determined at the beginning and end of surgery. Postoperative pain intensity was evaluated using a visual analog scale and recording the consumption of analgesics.
                There were no significant group-specific differences during the operation, neither in body temperature (group W: 36.1 +/- 0.4 degrees C vs group C: 35.7 +/- 0.6 degrees C) nor in intra-abdominal temperature (group W: 35.9 +/- 0.3 degrees C vs group C: 35.6 +/- 0. 6 degrees C). Postoperatively, the two groups did not differ in pain susceptibility and need of analgesics.
                The use of carbon dioxide gas warmed to body temperature to produce a pneumoperitoneum during short-term laparoscopic surgery has no clinically important effect. Patients undergoing warmed, humidified carbon dioxide (CO2) insufflation for laparoscopic cholecystectomy will (1) maintain a warmer intraoperative core temperature, (2) have their surgeon experience less fogging of the camera lens, and (3) have less postoperative pain than patients undergoing laparoscopic cholecystectomy with standard CO2 insufflation.
                A double-blind, prospective, randomized study comparing patients undergoing laparoscopic cholecystectomy with standard CO2 insufflation vs those receiving warmed, humidified CO2 (Insuflow Filter Heater Hydrator; Lexion Medical, St Paul, Minn) was performed. Main variables included patient core temperature, postoperative pain, analgesic requirements, and camera lens fogging.
                One hundred one blinded patients (69 women, 32 men) undergoing laparoscopic cholecystectomy were randomized into 2 groups-52 receiving standard CO2 insufflation (group A) and 49 receiving warmed, humidified CO2 (group B). Mean patient intraoperative core temperature change (group A decreased by 0.03 degrees C, group B increased by 0.29 degrees C, P =.01) and mean abdominal pain (Likert scale, 0-10) at 14 days postoperatively (group A, 1.0; group B, 0.3; P =.02) were different. Other variables (camera lens fogging, early postoperative pain, narcotic requirements, recovery room stay, and return to normal activities) between groups were similar.
                While patients undergoing laparoscopic cholecystectomy with warmed, humidified CO2 had several advantages that were statistically significant, no major clinically relevant differences between groups A and B were evident. Intraoperative hypothermia is a common event during laparoscopic operations. An external warming blanket has been shown to be effective in preventing hypothermia. It has now been proposed that using heated and humidified insufflation gas can prevent hypothermia and decrease postoperative pain. Therefore, we examined the extent of intraoperative hypothermia in patients undergoing laparoscopic Nissen fundoplication using an upper body warming blanket. We also attempted to determine whether using heated and humidified insufflation gas in addition to an external warming blanket would help to maintain intraoperative core temperature or decrease postoperative pain.
                Twenty patients were randomized to receive either standard carbon dioxide (CO2) gas (control, n = 10) or heated and humidified gas (heated and humidified, n = 10). After the induction of anesthesia, an external warming blanket was placed on all patients in both groups. Intraoperative core temperature and intraabdominal temperature were measured at 15-min intervals. Postoperative pain intensity was assessed using a visual analogue pain scale, and the amount of analgesic consumption was recorded. Volume of gas delivered, number of lens-fogging episodes, intraoperative urine output, and hemodynamic data were also recorded.
                There was no significant difference between the two groups in age, length of operation, or volume of CO2 gas delivered. Compared with baseline value, mean core temperature increased by 0.4 degrees C in the heated and humidified group and by 0.3 degrees C in the control group at 1.5 h after surgical incision. Intraabdominal temperature increased by 0.2 degrees C in the heated and humidified group but decreased by 0.5 degrees C in the control group at 1.5 h after abdominal insufflation. There was no significant difference between the two groups in visual analog pain scale (5.4 +/- 1.6 control vs 4.5 +/- 2.8 heated and humidified), morphine consumed (27 +/- 26 mg control vs 32 +/- 19 mg heated and humidified), urine output, lens-fogging episodes, or hemodynamic parameters.
                Heated and humidified gas, when used in addition to an external warming blanket, minimized the reduction of intraabdominal temperature but did not alter core temperature or reduce postoperative pain. Recent data has shown that the use of warmed, humidified carbon dioxide (CO2) insufflation during laparoscopic surgery may be associated with better outcomes.
                We performed a randomized, doubleblind, prospective controlled clinical trial of 30 patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGBP). Patients were randomized into 2 groups. The first group (group 1, n=15) received standard (dry, room temperature) CO2 for insufflation during the surgery, while the second group (group 2, n=15) received warmed (35 degrees C) and humidified (95%) CO2. Patients received postoperative analgesia from morphine delivered via a patient-controlled analgesia (PCA) pump. Pain scores (on a scale of 0 to 10, 0 being no pain and 10 being the worst pain) were measured postoperatively at 3 h, 6 h, 1 day and 2 days. The amount of morphine that was delivered through the PCA was also measured at the same time intervals. Operating-room (OR) time, core temperature, and total hospital length of stay were documented.
                Postoperative pain as documented by pain scores and narcotic usage were not statistically different in the 2 groups. We demonstrated a statistically significant difference (mean+/-SD) in OR time (76+/-16 min vs 101+/-34 min, P=0.02), total hospital length of stay (3.2+/-.4 days vs 4.0+/-.9 days, P=0.01) and end-of-case core temperature (36.2+/-.5 degrees C vs 35.7+/-.6 degrees C, P=0.02) in group 2 compared with group 1.
                The use of warmed, humidified CO2 insufflation in bariatric patients undergoing LRYGBP was not associated with any significant benefit with regards to postoperative pain. To determine whether use of heated humidified carbon dioxide as insufflation gas during gynecologic laparoscopy reduced postoperative pain and hypothermia.
                A randomized controlled trial (Canadian Task Force classification 1).
                A tertiary referral hospital.
                Sixty women scheduled for gynecologic laparoscopy between 30 and 90 minutes' duration.
                Operative laparoscopic management of endometriosis, adhesions, or adnexal pathology.
                Sixty patients were randomized into either receiving heated humidified carbon dioxide (study group) or standard cold dry gas (control group). Intraoperative and postoperative core temperature, total analgesic use, postoperative nausea, and recovery room time were recorded. Postoperative pain intensity was assessed using visual analog scale. Statistical analysis was performed using software. No significant difference was revealed between groups with regard to postoperative pain, analgesic requirements, recovery room time, or postoperative nausea. The control group had less postoperative hypothermia, suggesting that external warming blankets may be more effective than heated humidified gas at maintaining intraoperative normothermia.
                The use of heated humidified carbon dioxide insufflation for short-duration gynecologic laparoscopy up to 90 minutes' duration was not associated with any significant benefit with regard to postoperative pain, hypothermia, or time of recovery room stay.
The study offers evidence that during laparoscopic abdominal surgery, heated gas insufflation, with or without humidification, has minimal benefit on patient outcomes.