Effects of propranolol on the cardiovascular and renin-angiotensin systems during hypotension produced by sodium nitroprusside in humans

W. K. Marshall, R. F. Bedford, W. P. Arnold, E. D. Miller, D. E. Longnecker, M. D. Sussman, M. W. Hakala

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The authors examined the effects of controlled hypotension induced with sodium nitroprusside (SNP) with and without propranolol on the cardiovascular, pulmonary, and renin-angiotensin systems in 10 consecutive anesthetized patients with kyphoscoliosis undergoing posterior spinal fusion. SNP infusion (4.1 μg.kg-1.min-1) alone decreased mean systemic arterial pressure (SAP) by 25 torr ± 3 SE (P<0.001), systemic vascular resistance index (SVRI) by 1113 dyne.sec.cm-5.m2 ± 125 SE (P<0.001), mean pulmonary artery pressure (PAP) by 6 torr ± 2 SE (P<0.02), pulmonary capillary wedge pressure (PCWP) by 4 torr ± 1 SE (P<0.01), pulmonary vascular resistance (PVR) by 50 dyne.sec.cm-5 ± 18 (P<0.05), and Pa(O2) by 16 torr ± 7 SE (P<0.05), whereas cardiac index increased by 1.08 l.min-1 m2 ± 0.24 SE (P<0.01) and heart rate increased 16 beats/min ± 5 SE (P<0.02). After 40 min of hypotension, 0.03 mg/kg propranolol was injected intravenously while the SNP infusion rate was held constant. Ten min later there was a significant decrease in the heart rate (10 beats/min ± 4 SE, P<0.02) and cardiac index (0.65 l.min-1.min-1.m-2 ± 0.21, P<0.02). Plasma renin activity (PRA) increased from 2.37 ng.ml-1.h-1 ± 0.7 SE before anesthesia to 6.50 ng.ml-1.h-1 ± 1.45 SE (P<0.05) after 40 min of nitroprusside infusion. Forty min after propranolol there was a significant reduction in PRA to 4.07 ng.ml-1.h-1 ± 0.73 SE (P<0.05). Thus propranolol, when given during SNP hypotension, exhibits an early cardiovascular response manifested as a decrease in cardiac output and heart rate and a delayed action on the kidney resulting in an inhibition of renin release.

Original languageEnglish (US)
Pages (from-to)277-280
Number of pages4
JournalUnknown Journal
Issue number3
StatePublished - 1981

All Science Journal Classification (ASJC) codes

  • Anesthesiology and Pain Medicine

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