title: Intravenous labetalol for the treatment of hypertension after carotid endarterectomy.
abstract: Hypertension after carotid endarterectomy has a variable incidence ranging up to 56%. Blood pressure (BP) control is essential due to possible increased risk of morbidity from neurologic deficits or cardiovascular complications. This study evaluated intravenous labetalol for control of hypertension after carotid endarterectomy. Sixty ASA II-IV patients were studied; 20 developed BP high enough for treatment with labetalol. The anesthetic technique was standardized. Labetalol was administered at the conclusion of surgery as a 20-mg bolus over two minutes followed by 40 mg every 10 minutes until the desired BP was achieved (BP less than or equal to 10% above average preoperative BP or less than 150 mmHg, systolic) or 300 mg had been given. The mean total dose of labetalol was 42.0 +/- 33.0 mg (mean +/- SD) and mean time to reach the desired BP was 16.2 +/- 21.4 minutes. Systolic, diastolic, mean arterial pressure and heart rate significantly decreased after labetalol treatment and remained so for the remainder of the 180-minute study period. There was no hypotension, bradycardia, evidence of myocardial ischemia or central nervous system dysfunction present with labetalol treatment. Blood samples were obtained for determination of plasma renin activity, epinephrine, and norepinephrine in 10 patients who developed hypertension and received labetalol, and 10 patients who did not develop hypertension. In the patients developing hypertension, there was a significant elevation in epinephrine just before treatment, that decreased by 30 minutes after treatment. Norepinephrine levels became significantly elevated five minutes after labetalol treatment in the group with hypertension and remained elevated for 120 minutes. Concomitantly, there was a significantly lower plasma renin activity seen in this group.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107.
authors.forename: M E
authors.initials: ME
authors.lastname: Goldberg
authors.forename: J L
authors.initials: JL
authors.lastname: Seltzer
authors.forename: S S
authors.initials: SS
authors.lastname: Azad
authors.forename: S N
authors.initials: SN
authors.lastname: Smullens
authors.forename: A T
authors.initials: AT
authors.lastname: Marr
authors.forename: G E
authors.initials: GE
authors.lastname: Larijani
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D003000:Clonidine / Q000627:therapeutic use; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D004809:Ephedrine / Q000627:therapeutic use; D004837:Epinephrine / Q000097:blood; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D007022:Hypotension / Q000517:prevention & control; D007275:Injections, Intravenous; D007741:Labetalol / Q000627:therapeutic use*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood; D013997:Time Factors
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D012083:Renin; D004809:Ephedrine; D003000:Clonidine; D007741:Labetalol; D009638:Norepinephrine; D004837:Epinephrine