What question did this study set out to answer?

To determine the physiological mechanism responsible for morphine-induced shifts of blood volume between an extracorporeal reservoir and systemic circulation during constant blood flow and vena caval pressure.

April 1, 1978Circulation ResearchOpen Access

Mechanism of morphine-induced shifts in blood volume between extracorporeal reservoir and the systemic circulation of the dog under conditions of constant blood flow and vena caval pressures.

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To determine the physiological mechanism responsible for morphine-induced shifts of blood volume between an extracorporeal reservoir and systemic circulation during constant blood flow and vena caval pressure.
Evaluated 10 anesthetized dogs placed on right heart bypass with pump flow maintained at 80 ml/min/kg.
Administered 4 mg/kg of morphine and monitored arterial pressure, reservoir volume, hematocrit, radiolabeled plasma tracer volume, liver volume changes via scintillation probe, and ascites accumulation.
Arterial pressure fell from 99 ± 5 to 59 ± 6 mm Hg (P < 0.001) by 5 minutes, reservoir volume decreased by 578 ± 86 ml in 15 minutes, and central hematocrit increased from 0.41 ± 0.02 to 0.47 ± 0.01 (P < 0.01).
Plasma volume decreased by 317 ± 32 ml in 15 minutes (accounting for 58% of reservoir loss), accompanied by an immediate 30% increase in hepatic scintillation counts.
Ascites volume increased from 78 ± 24 ml to 276 ± 44 ml by 60 minutes (P < 0.001), reflecting filtration of pure plasma through liver sinusoids.

Structured PICO

Population

10 anesthetized dogs with right heart bypass

Intervention

Morphine 4 mg/kg

Outcome

Changes in arterial pressure, reservoir volume, central hematocrit, plasma volume, and ascites volumesurrogate

Morphine-induced decreases in extracorporeal reservoir volume in dogs are largely accounted for by blood trapped in the liver and plasma filtered at the liver sinusoids producing ascites.

Discussion

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Implication

Morphine may promote hepatic fluid shifts and ascites in dogs; leaves open relevance to human hemodynamics or practice.

Cite This Study

Green et al. (1978) studied this question.

synapsesocial.com/papers/6a95c4cd6cc0cb4cef420d4b https://doi.org/10.1161/01.res.42.4.479

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Mechanism of morphine-induced shifts in blood volume between extracorporeal reservoir and the systemic circulation of the dog under conditions of constant blood flow and vena caval pressures.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Mechanism of morphine-induced shifts in blood volume between extracorporeal reservoir and the systemic circulation of the dog under conditions of constant blood flow and vena caval pressures.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

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