Korean J Anesthesiol.  1998 Sep;35(3):404-412. 10.4097/kjae.1998.35.3.404.

Influence of Acute Pulmonary Hypertension on the Protamine-induced Systemic Hypotension in the Heparinized Dog

• Yoo KY
• Shim SJ
• Park JE
• Im WM

• KMID: 2240124
• DOI: http://doi.org/10.4097/kjae.1998.35.3.404

Abstract

INTRODUCTION
The present study was aimed to investigate the hemodynamic effects of protamine and to determine whether the increases of pulmonary arterial pressure (deltaPAP) after protamine is related to development of systemic hypotension in heparinized dogs.
METHODS
Nineteen mongrel dogs were acutely instrumented during 1.5% halothane anesthesia. All dogs then received protamine 3 mg.kg (-1) over a period of 30 s given through right atrium 5 minutes after heparin (300 IU.kg (-1), iv). Animals were retrospectively assigned into two groups, control (deltaPAP<6 mmHg, n=9) and pulmonary hypertensive (PHT, deltaPAP<6 mmHg, n=10) groups. Mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), left ventricular pressure, heart rate (HR), and cardiac output and left circumflex coronary flow (LCX flow) via Doppler flowmeter were continuously recorded throughout the experiments. Changes in MPAP were related to changes in MAP using standard regression analysis.
RESULTS
MPAP (66% in PHT vs 7% in control group) and pulmonary vascular resistance index (5.1- vs 3.0-fold) increased more markedly immediately after protamine administration in PHT group than in control group. However, protamine caused similar reductions of MAP (-40 vs -46%), cardiac index (-60 vs -59%), and left ventricular end- diastolic pressure (-47 vs -53%) in both groups. No correlation was found between deltaPAP and deltaMAP in either group. LCX flow increased significantly but similarly immediately after protamine in both groups (183 vs 238%), indicating rapid release of potent vasodilator.
CONCLUSIONS
These results suggest that, in heparinized dogs, protamine produces transient severe hypotension but does not consistently elevate pulmonary arterial pressure and, that acute pulmonary vasoconstriction does not play a major role in protamine-induced hypotension.

Keyword

Animal: dog; Blood, coagulation: heparin; protamine; Blood pressure: pulmonary hypertension; systemic hypotension

MeSH Terms

Anesthesia
Animals
Arterial Pressure
Blood Pressure
Cardiac Output
Control Groups
Dogs*
Flowmeters
Halothane
Heart Atria
Heart Rate
Hemodynamics
Heparin*
Hypertension, Pulmonary*
Hypotension*
Retrospective Studies
Vascular Resistance
Vasoconstriction
Ventricular Pressure
Halothane
Heparin