title: The effect of baricity of intrathecal morphine in children receiving tetracaine spinal anaesthesia for cardiac surgery: a preliminary report.
abstract: BACKGROUND
  This prospective, randomized study examined the effect of baricity of intrathecal preservative-free morphine on the duration of postoperative analgesia and incidence of side-effects in infants and children receiving high spinal anaesthesia with hyperbaric tetracaine in combination with a light general anaesthetic.
  
  
  METHODS
  Fourteen infants and children, aged 7-91 months, undergoing repair of either uncomplicated atrial or ventricular septal defects, were randomized to receive either 10 microg x kg(-1) of intrathecal morphine in combination with 0.5% tetracaine D10 (hyperbaric morphine group) or intrathecal morphine mixed with saline and injected sequentially after the administration of 0.5% tetracaine D10 (hypobaric morphine group). After spinal injection, patients were positioned in 30 degrees of Trendelenburg for a minimum of 10 min. Postoperatively, patients were monitored for a minimum of 12 h. Pain scores and the incidence and severity of side-effects were recorded every 1 h.
  
  
  RESULTS
  All patients were extubated at the conclusion of surgery without any incidence of respiratory depression. There was a decreased incidence of vomiting in the hypobaric morphine group and no significant difference in the duration of analgesia.
  
  
  CONCLUSIONS
  When intrathecal morphine is administered in conjunction with a hyperbaric tetracaine spinal to paediatric cardiac patients in the head down position, sequential administration of the hypobaric solution may mitigate side-effects.
authors: Children's National Medical Center, Washington, DC, USA, Stanford University School of Medicine, Stanford, CA, USA. jfinkel@cnmc.org
authors: Julia C
authors: JC
authors: Finkel
authors: M Gail
authors: MG
authors: Boltz
authors: Aisling M
authors: AM
authors: Conran
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local; D002648:Child; D002675:Child, Preschool; D006343:Heart Septal Defects / Q000601:surgery*; D006801:Humans; D007223:Infant; D007278:Injections, Spinal; D009020:Morphine / Q000008:administration & dosage; D010149:Postoperative Pain / Q000517:prevention & control; D011187:Posture; D011312:Pressure; D011446:Prospective Studies; D013748:Tetracaine
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D013748:Tetracaine; D009020:Morphine