Anaesthesia

Anaesthesia
     

• Shende D, Cooper GM, Bowden (AIIMS, New Delhi, India; Birmingham Women’s Hosp, England)
  The Influence of Intrathecal Fentanyl on the Characteristics of Subarachnoid Block for Caesarean
  Section.
  Anaesthesia 53: 706-710, 1998
    
  Objective : Whether the addition of an opioid to intrathecal solutions improves intraoperative comfort is unknown. The effect of
  adding 15µg fentanyl to hyperbaric 0.5% bupivacaine given intrathecally for elective cesarean section was investigated in a
  randomized, double-blind study.
    
  Methods: Either 15 µg fentanyl or 0.3cc preservative-free 0.9% saline was added to 2.5mL hyperbaric 0.5% bupivacaine for
  subarachnoid block and administered to 40 healthy laboring women undergoing elective cesarean section.
    
  Results : Onset times for the fentanyl group and the saline group were similar. Whereas ephedrine and morphine requirements
  were similar, the fentanyl group did not require morphine until significantly later than the saline group, and the duration of
  blockade was significantly longer in the fentanyl group than in the saline group. Seven of the saline group and none of the
  fentanyl group experienced discomfort. Neonatal outcomes and maternal side effects were similar for the 2 groups.
     
  Conclusions : Addition of fentanyl to intrathecally administered 0.5% bupivacaine improved the quality and duration of analgesia.
         

• Ngan Kee WD, Khaw KS, Ma ML, et al (Chinese Univ of Hong Kong)
  Postoperative Analgesic Requirement After Cesarean Section: A Comparison of Anesthetic Induction With Ketamine or Thiopental.
  Anesth Analg 85: 1294-1298, 1997
       
  Background: The standard general anesthetic for women undergoing cesarean section consists of induction with thiopental. Opioids are omitted until after delivery. However, thiopental has no analgesic properties. By contrast, ketamine is a potent analgesic. The effects of ketamine on pain after cesarean section has not been studied. The effects of anesthetic induction with ketamine or thiopental were compared in women having elective cesarean section.
     
  It was concluded that the use of ketamine to induce anaesthesia in women undergoing cesarean section is associated with reduced postoperative analgesic requirements compared with thiopental. Unlike thiopental, ketamine has analgesic properties that may decrease sensitization of pain pathways, extending into the postoperative period.
     
  Editorial comment by S.E. Abram, MD: The effect of preincisional ketamine on postoperative analgesia and opiate requirement was quite modest in this study. This is not surprising because, only a single small dose was administered. This study should be repeated, using higher doses and continued intraoperative administration, in patients undergoing surgery that typically produces substantial pain, e.g. lateral thoracotomy.