title: Supplementary oxygen for emergency Caesarean section under regional anaesthesia.
abstract: BACKGROUND
  Controversy still exists if the administration of supplementary oxygen to patients having emergency Caesarean section (CS) under regional anaesthesia is beneficial or potentially harmful. Therefore, in a prospective double-blinded study, we randomized patients having emergency CS under regional anaesthesia to receive either air or 60% oxygen until delivery and compared the effects on fetal oxygenation and lipid-peroxidation in the mother and baby.
  
  
  METHODS
  We recruited 131 women having emergency CS under regional anaesthesia. Either 21% (air group) or 60% oxygen (oxygen group) was administered using a Venturi-type facemask until delivery. We compared the oxygen exposure duration, umbilical arterial (UA) and venous (UV) blood gases and oxygen content, and plasma concentration of 8-isoprostane. Subanalysis was performed according to whether or not fetal compromise was considered present.
  
  
  RESULTS
  Data from 125 patients were analysed. For the oxygen group vs the air group, there were greater values for UA PO(2) [mean 2.2 (SD 0.5) vs 1.9 (0.6) kPa, P=0.01], UA O(2) content [6.6 (2.5) vs 4.9 (2.8) ml dl(-1), P=0.006], UV PO(2) [3.8 (0.8) vs 3.2 (0.8) kPa, P<0.0001], and UV O(2) content [12.9 (3.5) vs 10.4 (3.8) ml dl(-1), P=0.001]. There was no difference between the groups in maternal, UA, or UV 8-isoprostane concentration. Apgar scores and UA pH were similar between the groups. Similar changes were observed regardless of whether fetal compromise was considered present (n=37) or not (n=88).
  
  
  CONCLUSIONS
  Breathing 60% oxygen during emergency CS under regional anaesthesia increased fetal oxygenation with no associated increase in lipid-peroxidation in the mother or fetus.
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China. kimkhaw@cuhk.edu.hk
authors.forename: K S
authors.initials: KS
authors.lastname: Khaw
authors.forename: C C
authors.initials: CC
authors.lastname: Wang
authors.forename: W D
authors.initials: WD
authors.lastname: Ngan Kee
authors.forename: W H
authors.initials: WH
authors.lastname: Tam
authors.forename: F F
authors.initials: FF
authors.lastname: Ng
authors.forename: L A H
authors.initials: LA
authors.lastname: Critchley
authors.forename: M S
authors.initials: MS
authors.lastname: Rogers
mesh_terms: D000293:Adolescent; D000328:Adult; D000765:Anesthesia, Conduction / Q000379:methods*; D000773:Anesthesia, Obstetrical / Q000379:methods*; D001034:Apgar Score; D002585:Cesarean Section; D004311:Double-Blind Method; D004630:Emergencies; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects; D010108:Oxyhemoglobins / Q000378:metabolism; D010313:Partial Pressure; D011247:Pregnancy; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D010108:Oxyhemoglobins; D010100:Oxygen