Humidification in Laparoscopic Colonic Surgery 6/2/2018 11:46 AM Humidification in Laparoscopic Colonic Surgery Tarik Sammour Arman Kahokehr Mike Hulme-Moir Julian Hayes Andrew G Hill © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Normal peritoneal mesothelium Close-up 30min of pneumoperitoneum 24h later 12h later Caused by desiccation from cold, dry gas. Normal: Intact mesothelial surface and indistinct cell borders. 2h: Mesothelial cells bulged and retracted Closeup: Underlying basal lamina visible 12 h: Cells are largely denuded 24h: Macrophages and lymphocytes

Warming and Humidification Proposed Solution: Warming and Humidification of laparoscopic gas Water chamber 4-in-1 probe Heated Tube Humidifier

Meta-analysis (Sammour et al, Br J Surg 2008) 7 RCT’s: Upper GI / Gynae Reduction in post-op pain Reduction in post-op opiate use Limitations Poor quality studies Unblinded studies Did not standardise Bair Hugger use No studies in prolonged laparoscopy

Hypothesis In laparoscopic colectomy, warming and humidification of insufflation gas will reduce post-op pain by decreasing peritoneal desiccation.

Methods - Patients All patients > 15 yrs undergoing laparoscopic colon resection in three Auckland hospitals Exclusions: Rectal lesions (below 15cm on colonoscopy) Patient requiring stoma Hand-assisted resections ASA > 4 Steroid dependent

Methods - Groups Intervention Control Standardized protocol Humidified and warmed CO2 Control Standard CO2 Standardized protocol Room temp 19 °C Bair hugger in all cases Standardised analgesia Randomization Computer generated random numbers Stratified by site Opaque envelopes opened in OT Premed: Paracetamol 1g Dexamethasone 8mg Intraop: Morph / Fentanyl (wt based) Postop: Morph / Fentanyl PCA

Methods - Blinding Patient, surgical team, investigators blind Humidifier always attached Covered with specially designed PVC cover Single unblinded research assistant Data analysis also blinded

Methods - Power Morphine Equivalent Daily Dose (MEDD) Mean from 3 published RCTs = 137 + 41 mg Conservative estimate = 150 + 50mg 20% reduction clinically significant Powered for: α 0.05 and β 0.80 Sample size required = 74 patients

Outcomes Morphine Equivalent Daily Dose (MEDD) Pain Visual Analogue Score (VAS) Intra-op core temperature Camera fogging Plasma & peritoneal cytokine response Post-op recovery PACU Day 1 Day 2 Day 3 TOTAL 2h 4h 8h 12h Day 1 Day 2 Day 3 Day 7 Day 14 Day 30 Day 60 Pain was measured using visual analogue scores at rest, moving, and coughing. Intraop temperature was measured at 15 minutes intervals using a nasopharyngeal probe. At the conclusion of surgery, the primary surgeon was asked to rate camera fogging on a Likert scale (1 perfect image, 10 very poor quality image). Peritoneal and plasma cytokine concentrations were measured at 20 hours postoperatively. Postop recovery was measured using defined discharge and complication criteria, and the Surgical Recovery Score.

Patients assessed for eligibility Did not meet incl criteria April 2008 – June 2009 Patients assessed for eligibility n = 111 Did not meet incl criteria n = 29 Randomised n = 82 Intervention n = 41 Control n = 41 Analysed n = 35 Excluded n = 6 Rectal Ca intraop n = 2 No colon resected n = 2 Un-blinding n = 1 Stoma n = 1 Analysed n = 39 Excluded n = 2 No colon resected n = 1 Anaphylaxis n = 1

No Difference Baseline Humidified (n = 35) Control (n = 39) P Value Age (median, IQR) 71 (29) 69 (22) 0.959 Sex Male Female 15 (42.9%) 20 (57.1%) 16 (41.0%) 23 (59.0%) 1.000 BMI (mean, SD) 26.5 (4.8) 25.5 (5.4) 0.401 ASA score I II III 6 (17.1%) 21 (60.0%) 8 (22.9%) 3 (7.7%) 13 (33.3%) 0.355 CR-POSSUM (median, IQR) 17 (5) 19 (5) 0.178 Previous surgery 0.475 Operation Ileocolic resection R hemicolectomy Extended R hemicolectomy Transverse colectomy L hemicolectomy Sigmoid colectomy High anterior resection 5 (14.3%) 14 (40.0%) 1 (2.9%) 2 (5.7%) 7 (20.0%) 0 (0%) 11 (28.2%) 1 (2.6%) 6 (15.4%) 2 (5.1%) 0.073 No Difference Baseline

Intra-operative Humidified (n = 35) Control (n = 39) P Value Operating Time (mean, SD) Total operating time Pneumoperitoneum time 176.3 (48.8) 105.1 (39.0) 184.7 (57.5) 116.9 (55.0) 0.504 0.295 Volume CO2 used (mean, SD) 113.9 (110.1) 178.4 (170.4) 0.057 Conversion to laparotomy Converted Not converted 2 (5.7%) 33 (94.3%) 6 (15.4%) 33 (84.6%) 0.267 Total wound size (median, IQR) 10.0 (5.0) 11.3 (6.0) 0.451 Camera fogging score (median, IQR) 4 (5) 2 (3) 0.040 Intra-operative

P = 0.324

No Difference Opiate Use Humidified (n = 35) Control (n = 39) P Value MEDD use (median, IQR) Intra-op PACU Day 0 Day 1 Day 2 Day 3 Total 35.0 (17.5) 10.0 (16.0) 12.0 (22.0) 22.0 (28.5) 16.0 (21.5) 7.5 (21.0) 77.0 (95.0) 35.0 (26.0) 8.0 (18.0) 9.0 (17.0) 36.0 (41.0) 20.0 (32.0) 10.0 (21.0) 94.4 (107.0) 0.728 0.783 0.516 0.344 0.156 0.364 0.414 No Difference Opiate Use

P = 0.010 Rest P = 0.018 Pain by VAS Moving P = 0.006 Coughing

No Difference Recovery Humidified (n = 35) Control (n = 39) P Value Discharge (median, IQR) Met discharge criteria Actual discharge day Total day stay 3 (3) 5 (5) 7 (7) 3 (2) 5 (6) 5 (7) 0.755 0.750 0.873 Complication Grade I II III IV 1 (5.3%) 15 (78.9%) 3 (15.8%) 0 (0%) 13 (68.4%) 2 (10.5%) 0.543 Surgical Recovery Score Baseline Day 1 Day 3 Day 7 Day 30 Day 60 72.9 (13.7) 52.2 (21.0) 54.3 (14.3) 58.8 (14.5) 67.4 (15.6) 74.7 (13.5) 72.9 (14.4) 52.3 (16.1) 50.6 (18.5) 52.2 (15.1) 69.5 (14.6) 72.4 (16.4) 0.977 0.986 0.381 0.077 0.598 0.580 No Difference Recovery Readmission: 23% vs 8%, P = 0.102 3 leaks in control group, 2 in study group

Cytokines P = 0.50 P = 0.70 Peritoneal Plasma

Conclusion Warming and humidification of insufflation CO2 does not reduce pain or peritoneal inflammation after laparoscopic colonic surgery.