title: Hemodynamic stability after intraarterial injection of verapamil for cerebral vasospasm.
abstract: BACKGROUND
  Vasospasm after subarachnoid hemorrhage is a common and potentially life-threatening complication. Treatment of vasospasm may include intraarterial (IA) injections of verapamil into the cerebral vasculature. Clinical experience suggests that the average patient experiences an acute reduction in systemic blood pressure after IA verapamil. Our study objective was to (1) identify the effects of IA injection of verapamil on mean arterial blood pressure (MAP) and heart rate (HR) in patients with cerebral vasospasm and (2) determine the effect of verapamil dose on change in MAP and HR. We hypothesized that (1) selective IA injection of verapamil for treatment of cerebral vasospasm is associated with a reduction in MAP and an increase in HR and (2) the change in MAP and HR are linearly related to the dose of verapamil administered.
  
  
  METHODS
  We prospectively studied subjects with vasospasm scheduled for cerebral angiography with possible IA injection of verapamil. All subjects were given a general anesthetic. Invasive arterial blood pressure and HR were monitored continuously and recorded at 10-second intervals throughout the procedure. We identified the lowest MAP and highest HR before and after verapamil injection. The association between IA verapamil and change in MAP and HR was determined using repeated-measures multivariate regression analysis, adjusting for potential confounding factors (weight, preoperative vasopressor use, and preinjection MAP). Data are reported as adjusted coefficients and 95% confidence intervals (CI).
  
  
  RESULTS
  We included 20 subjects who underwent a total of 46 injections of IA verapamil. On the basis of our multivariate model, on average, each 5 mg of IA verapamil was associated with a 3.5 mm Hg reduction in MAP (95% CI -5.0 to -2.0, P < 0.001). HR was not significantly altered by IA verapamil on both unadjusted and adjusted analyses (nonsignificant increase of 0.4 beats per minute for each 5 mg of IA verapamil, 95% CI -1.6 to 2.4, P = 0.70).
  
  
  CONCLUSIONS
  Under general anesthesia, injection of IA verapamil into cerebral arteries reduces MAP but does not change HR in the average patient. Further research is required to determine the clinical significance of these results.
authors.affiliation: Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA. alana.flexman@vch.ca
authors.forename: Alana M
authors.initials: AM
authors.lastname: Flexman
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ryerson
authors.forename: Pekka O
authors.initials: PO
authors.lastname: Talke
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D001794:Blood Pressure / Q000187:drug effects; D001955:British Columbia; D002536:Cerebral Arteries / Q000187:drug effects* / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007269:Injections, Intra-Arterial; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D012044:Regression Analysis; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000008:administration & dosage*; D020301:Vasospasm, Intracranial / Q000188:drug therapy* / Q000503:physiopathology; D014700:Verapamil / Q000008:administration & dosage*
chemical_list: D014665:Vasodilator Agents; D014700:Verapamil