title: The effect of head-down tilt position on arterial blood pressure after spinal anesthesia for cesarean delivery.
abstract: OBJECTIVE
  The effect of the head-down tilt position after induction of spinal anesthesia for cesarean delivery on blood pressure and level of sensory block was examined.
  
  
  METHODS
  Patients were allocated randomly into two groups, the head-down tilt group (n = 17) and the horizontal group (n = 17). In the head-down tilt group, patients were positioned with a 10 degrees head-down tilt immediately after supine positioning, while those in the horizontal group were maintained in a horizontal position. All patients received 500 mL of lactated Ringer's solution intravenously over 10 minutes prior to spinal injection, a wedge was placed under the patient's right hip, and the operating table was rotated 5 degrees in a counterclockwise direction to provide left uterine displacement. Hypotension (defined as systolic blood pressure below 100 mm Hg) was treated with 5 mg ephedrine intravenously and an increase in the infusion rate of lactated Ringer's solution. The change in systolic blood pressure was expressed as percent change from the baseline value.
  
  
  RESULTS
  Systolic blood pressure decreased 20% at 3 minutes after spinal block in both groups but recovered to half of this decrease. The incidence of postspinal hypotension was not different between the two groups. The total amount of ephedrine and lactated Ringer's solution administered during the first 20 minutes of spinal block did not differ between the two groups nor did the extent of the cephalad spread of analgesia 20 minutes after spinal block (T4 +/- 2 vs T4 +/- 1 for the head-down and horizontal groups, respectively).
  
  
  CONCLUSIONS
  The head-down position is concluded to have no effect on the incidence of hypotension during spinal anesthesia for cesarean delivery.
authors.affiliation: Department of Anesthesiology, Institute of Clinical Medicine, University of Tsukuba, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Miyabe
authors.forename: S
authors.initials: S
authors.lastname: Sato
mesh_terms: D000328:Adult; D000773:Anesthesia, Obstetrical; D000775:Anesthesia, Spinal; D001794:Blood Pressure / Q000502:physiology*; D002585:Cesarean Section; D005260:Female; D018475:Head-Down Tilt; D006801:Humans; D010147:Pain Measurement; D011247:Pregnancy