Gareth A Charlton1, David R Ladd2, Richard M Friesen3, Robert H Friesen4. 1. Shackleton Department of Anaesthesia, University Hospitals Southampton NHS Trust, Southampton, UK. 2. Department of Anesthesiology, Children's Hospital Colorado, Aurora, CO. 3. Division of Cardiology, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO. 4. Department of Anesthesiology, Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, CO. Electronic address: robert.friesen@childrenscolorado.org.
Abstract
OBJECTIVE: Paradoxical hypertension after repair of coarctation of the aorta in children is associated with the release of catecholamines and activation of the renin-angiotensin system. The objective of the present study was to describe the effects of labetalol infusion on blood pressure, plasma catecholamine levels, and plasma renin activity in a series of children undergoing repair of coarctation of the aorta. DESIGN: Prospective, observational cohort study. SETTING: Tertiary children's hospital with university affiliation. PARTICIPANTS: The study was comprised of 15 consecutive children older than 1 year undergoing repair of coarctation of the aorta. INTERVENTIONS: Intravenous infusion of labetalol, up to 20 µg/kg/min, was administered when patients became hypertensive after release of the aortic cross-clamp. Supplementation with nitroprusside was allowed as needed. MEASUREMENTS AND MAIN RESULTS: Blood pressure was maintained below baseline values throughout the labetalol infusion. Plasma norepinephrine increased from 160 ± 81 pg/mL (preoperative) to 657 ± 268 pg/mL (6 h after release of aortic cross-clamp). Plasma renin activity decreased from 16.6 ± 9.7 ng/kg/h (at cross-clamp release) to 2.2 ± 2.2 ng/kg/h (6 h after cross-clamp release). Nitroprusside was added for 12 patients, at a highest mean dose of 2.4 ± 2.5 μg/kg/min. CONCLUSIONS: Labetalol inhibited activation of the renin-angiotensin system and helped control paradoxical hypertension after coarctation repair in children.
OBJECTIVE: Paradoxical hypertension after repair of coarctation of the aorta in children is associated with the release of catecholamines and activation of the renin-angiotensin system. The objective of the present study was to describe the effects of labetalol infusion on blood pressure, plasma catecholamine levels, and plasma renin activity in a series of children undergoing repair of coarctation of the aorta. DESIGN: Prospective, observational cohort study. SETTING: Tertiary children's hospital with university affiliation. PARTICIPANTS: The study was comprised of 15 consecutive children older than 1 year undergoing repair of coarctation of the aorta. INTERVENTIONS: Intravenous infusion of labetalol, up to 20 µg/kg/min, was administered when patients became hypertensive after release of the aortic cross-clamp. Supplementation with nitroprusside was allowed as needed. MEASUREMENTS AND MAIN RESULTS: Blood pressure was maintained below baseline values throughout the labetalol infusion. Plasma norepinephrine increased from 160 ± 81 pg/mL (preoperative) to 657 ± 268 pg/mL (6 h after release of aortic cross-clamp). Plasma renin activity decreased from 16.6 ± 9.7 ng/kg/h (at cross-clamp release) to 2.2 ± 2.2 ng/kg/h (6 h after cross-clamp release). Nitroprusside was added for 12 patients, at a highest mean dose of 2.4 ± 2.5 μg/kg/min. CONCLUSIONS:Labetalol inhibited activation of the renin-angiotensin system and helped control paradoxical hypertension after coarctation repair in children.