title: Case report: profound hypotension associated with labetalol therapy in a patient with cerebral aneurysms and subarachnoid hemorrhage.
abstract: OBJECTIVE
  Labetalol is an effective antihypertensive medication frequently used to treat systemic hypertension in acute care settings, including the management of hypertension associated with a subarachnoid hemorrhage. We present a case of profound hypotension, refractory to inotropic and vasopressor therapy following an iv infusion of labetalol.
  
  
  METHODS
  Initiation of an iv labetalol infusion resulted in good blood pressure control in a patient suffering from a Fisher grade 3 subarachnoid hemorrhage with an initial Glascow coma scale of 14/15 and mild hydrocephalus. Progressive deterioration of neurological symptoms and evidence of worsening hydrocephalus preceded the sudden development of profound hypotension (60/35 mmHg) and bradycardia with a minimum heart rate of 40 beats.min(-1). Initial resuscitative efforts included administration of intravascular fluid, hypertonic saline, atropine, adrenalin (more than 10 mg in divided doses) and noradrenalin. These measures restored the blood pressure to 80/45 with a HR of 98 beats.min(-1). Intraoperative placement of an intraventricular drain released cerebrospinal fluid under pressure with an initial intracranial pressure of 15 cm H(2)O. A combination of adrenalin, noradrenalin, dopamine and vasopressin infusions were required to restore the blood pressure to 130/65 mmHg after an additional two hours. All inotropic and vasopressor support was weaned off after the 14th hr (about two drug half-lives). The patient was awake and responsive the following day, with no obvious neurological consequences. No evidence of neurological injury, drug administration error or myocardial dysfunction was documented.
  
  
  CONCLUSIONS
  The episode of profound hypotension which occurred after initiating a labetolol infusion required maximal combined vasopressor therapy to restore the blood pressure suggesting that this patient demonstrated an extreme sensitivity to labetalol. Combination therapy with adrenergic and nonadrenergic agonists may be required for optimal treatment of profound hypotension associated with labetalol-induced vasoplegia.
authors.affiliation: Department of Anesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada.
authors.forename: Sana
authors.initials: S
authors.lastname: Jivraj
authors.forename: C David
authors.initials: CD
authors.lastname: Mazer
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Baker
authors.forename: Mabel
authors.initials: M
authors.lastname: Choi
authors.forename: Gregory M T
authors.initials: GM
authors.lastname: Hare
mesh_terms: D000959:Antihypertensive Agents / Q000009:adverse effects*; D001919:Bradycardia / Q000139:chemically induced / Q000188:drug therapy; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004298:Dopamine / Q000008:administration & dosage; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007022:Hypotension / Q000139:chemically induced* / Q000175:diagnosis* / Q000188:drug therapy; D002532:Intracranial Aneurysm / Q000150:complications*; D007741:Labetalol / Q000009:adverse effects*; D008875:Middle Aged; D009638:Norepinephrine / Q000008:administration & dosage; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000008:administration & dosage; D014667:Vasopressins / Q000008:administration & dosage
chemical_list: D000959:Antihypertensive Agents; D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents; D014667:Vasopressins; D007741:Labetalol; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine