title: Randomized clinical trial to evaluate the effects of perioperative supplemental oxygen administration on the colorectal anastomosis.
abstract: BACKGROUND
  Perioperative supplemental oxygen therapy may have beneficial effects on wound healing following colorectal surgery. The aim of this study was to evaluate the effects of such therapy on colorectal anastomotic pH and partial pressure of carbon dioxide (PCO(2)) gap.
  
  
  METHODS
  Forty-five patients undergoing anterior resection for rectal or sigmoid cancer were randomized to receive 30 or 80 per cent perioperative oxygen. Administration was commenced after induction of anaesthesia and maintained for 6 h after surgery. Intragastric and anastomotic tonometric catheters were placed in each patient and intramucosal pH (pHi) was measured immediately after operation, and 6 and 24 h later. Gastric and anastomotic pHi and PCO(2) gap in each group were compared.
  
  
  RESULTS
  There was a significantly lower anastomotic pHi and wider PCO(2) gap for gastric readings in the 30 per cent O(2) group, both 30 min (pHi, P = 0.006; PCO(2) gap, P = 0.006) and 6 h (pHi, P = 0.024; PCO(2) gap, P = 0.036) after surgery. There were no differences 24 h after surgery while breathing room air (pHi, P = 0.131; PCO(2) gap P = 0.139). No difference was found between gastric and anastomotic readings at any time point in the 80 per cent O(2) group.
  
  
  CONCLUSIONS
  Perioperative administration of 80 per cent O(2) both during surgery and for 6 hours afterwards is associated with an improvement in relative anastomotic hypoperfusion as assessed by the measurement of pHi and PCO(2) gap.
authors.affiliation: Colorectal Unit, Department of General and Digestive Surgery, Hospital Clínico, University of Valencia, Avenida Blasco Ibañez 17, 46010 Valencia, Spain. stephaniegarcia@wanadoo.es
authors.forename: S A
authors.initials: SA
authors.lastname: García-Botello
authors.forename: E
authors.initials: E
authors.lastname: García-Granero
authors.forename: R
authors.initials: R
authors.lastname: Lillo
authors.forename: F
authors.initials: F
authors.lastname: López-Mozos
authors.forename: M
authors.initials: M
authors.lastname: Millán
authors.forename: S
authors.initials: S
authors.lastname: Lledó
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000714:Anastomosis, Surgical / Q000379:methods; D001785:Blood Gas Monitoring, Transcutaneous; D015179:Colorectal Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D019990:Perioperative Care / Q000379:methods; D011446:Prospective Studies; D016896:Treatment Outcome; D014945:Wound Healing / Q000187:drug effects