Filling and arterial pressures as determinants of RV stroke volume in the sheep fetus.

Kent Thornburg, M. J. Morton

    Research output: Contribution to journalArticle

    81 Citations (Scopus)

    Abstract

    Right ventricular (RV) function was investigated in nine fetal lambs (125-130 days gestation) that were instrumented with pulmonary artery electromagnetic flow sensors and vascular catheters. Control arterial CO2 and O2 tension, pH, and hematocrit values were 46.1 +/- 1.6 (SD) Torr, 20.6 +/- 1.8 Torr, 7.39 +/- 0.02, and 31 +/- 5.3%, respectively. Control values for right ventricular output (247 +/- 75 ml X min-1 X kg-1), stroke volume (SV, 1.5 +/- 0.4 ml X kg-1), right atrial pressure (3.7 +/- 1.2 mmHg), heart rate (166 +/- 18 beats X min-1), and arterial pressure (AP, 43 +/- 4 mmHg) were unchanged by administration of atropine and propranolol. Withdrawal and infusion of fetal blood with or without concomitant infusion of nitroprusside or phenylephrine produced RV function curves at low, normal, and high arterial pressures. All function curves had a steep ascending limb and a plateau. The breakpoint joining the limbs of the control curve was right atrial pressure 3.4 +/- 1.2 mmHg and SV 1.5 +/- 0.4 ml X kg-1. Increased AP shifted the breakpoint downward. Linear regression of SV on AP from 15 to 95 mmHg at right atrial pressure greater than breakpoint was SV = -0.016 ml X kg-1 mmHg-1 X AP + 2.25 ml X kg-1.

    Original languageEnglish (US)
    JournalThe American journal of physiology
    Volume244
    Issue number5
    StatePublished - May 1983

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    Atrial Pressure
    Stroke Volume
    Right Ventricular Function
    Sheep
    Arterial Pressure
    Fetus
    Extremities
    Vascular Access Devices
    Electromagnetic Phenomena
    Transcription Factor AP-1
    Nitroprusside
    Phenylephrine
    Fetal Blood
    Atropine
    Hematocrit
    Propranolol
    Pulmonary Artery
    Linear Models
    Heart Rate
    Pregnancy

    ASJC Scopus subject areas

    • Medicine(all)

    Cite this

    Filling and arterial pressures as determinants of RV stroke volume in the sheep fetus. / Thornburg, Kent; Morton, M. J.

    In: The American journal of physiology, Vol. 244, No. 5, 05.1983.

    Research output: Contribution to journalArticle

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