title: Transdermal oxygen does not improve sternal wound oxygenation in patients recovering from cardiac surgery.
abstract: BACKGROUND
  Sternal wound dehiscence and infection complicate 1% of cardiac surgeries. Tissue oxygen tension (PsqO(2)) is the primary determinant of surgical wound infection risk and is often critically low in surgical incisions. We tested the hypothesis that local transdermal delivery of oxygen improves oxygenation in sternotomy wounds after cardiac surgery. Our secondary hypothesis was that supplemental inspired oxygen improves sternal wound PsqO(2).
  
  
  METHODS
  After undergoing cardiopulmonary bypass, 30 patients randomly received (1) 2 EpiFlo oxygen generators (Ogenix, Inc., Beachwood, OH) that provided oxygen at 6 mL/h into an occlusive wound dressing or (2) identical-appearing inactive generators. PsqO(2) and temperature were measured in the wound approximately 5 mm below the skin surface. PsqO(2) and arterial oxygen (Pao(2)) were measured 1 h after intensive care unit admission (Fio(2) = 60%) and on the first and second postoperative mornings at Fio(2) of both 30% and 50% in random order.
  
  
  RESULTS
  Data from four patients were excluded for technical reasons. Patient characteristics were similar in each group, as were type of surgery and perioperative management. Increasing Fio(2) from 30% to 50% improved Pao(2) from 99 [84-116] to 149 [128-174] mm Hg (P < 0.001, mean [95% CI]) and sternal wound PsqO(2) from 23 [16-33] to 27 [19-38] mm Hg (P < 0.001). In contrast, local oxygen delivery did not improve tissue oxygenation: 24 [14-41] vs 25 [16-41] mm Hg (P = 0.88).
  
  
  CONCLUSIONS
  Additional inspired oxygen improved Pao(2) and sternal wound PsqO(2) after bypass and may, consequently, reduce infection risk. However, oxygen insufflated locally into an occlusive dressing did not improve wound PsqO(2) and, therefore, does not appear to be useful clinically in cardiac surgery patients to reduce sternal wound infections.
authors.affiliation: Department of Outcomes Research, Cleveland Clinic, Cleveland, OH 44195, USA.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Bakri
authors.forename: Hassan
authors.initials: H
authors.lastname: Nagem
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Sessler
authors.forename: Ramatia
authors.initials: R
authors.lastname: Mahboobi
authors.forename: Jarrod
authors.initials: J
authors.lastname: Dalton
authors.forename: Ozan
authors.initials: O
authors.lastname: Akça
authors.forename: Eric E
authors.initials: EE
authors.lastname: Roselli
authors.forename: Steven R
authors.initials: SR
authors.lastname: Insler
mesh_terms: D000279:Administration, Cutaneous; D000280:Administration, Inhalation; D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D007327:Insufflation; D008297:Male; D008875:Middle Aged; D009779:Occlusive Dressings; D010100:Oxygen / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism; D010865:Pilot Projects; D013249:Sternum / Q000601:surgery*; D013530:Surgical Wound Infection / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D016896:Treatment Outcome; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D010100:Oxygen