title: Acute changes in bladder volume produce minimal cardio-respiratory responses in lightly anesthetised humans.
abstract: OBJECTIVE
  To examine whether changes in bladder volume elicit reflex cardiovascular and respiratory responses in humans under general anesthesia with sevoflurane and nitrous oxide.
  
  
  METHODS
  Fourteen patients free of autonomic disorders were anesthetized with sevoflurane 0.5% and nitrous oxide 60% in oxygen that were approximately equivalent to 0.9 MAC. Warmed saline (6 ml x kg(-1), 37 degrees C) was instilled into the pre-emptied urinary bladder, and then the bladder was kept distended for five minutes. Following the distension, the instilled saline was drained to the pre-instilled volume of the bladder Arterial blood pressure, respiratory flow, and intra-vesicle pressure were continuously measured, and mean arterial pressure, pulse rate, respiratory rate, tidal volume, and minute ventilation were estimated offline from these signals.
  
  
  RESULTS
  Bladder emptying produced small decreases in mean blood pressure (from 83.4+/-4.3 to 80.0+/-4.4 mm Hg, mean +/- SE, P = 0.017) and pulse rate (from 72.2+/-2.9 to 69.4+/-2.7 bpm, mean +/- SEM, P = 0.004). Only minimal respiratory reflexes were invoked by the bladder volume changes.
  
  
  CONCLUSIONS
  In lightly anesthetized humans, the acute changes in bladder volume produce only mild cardiovascular and respiratory responses.
authors.affiliation: Department of Anesthesiology, Chiba University School of Medicine, Japan. iteru@anesth01.m.chiba-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: J
authors.initials: J
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Nishino
mesh_terms: D000328:Adult; D000368:Aged; D000758:Anesthesia; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012018:Reflex; D012119:Respiration; D001743:Urinary Bladder / Q000502:physiology*