What question did this study set out to answer?

Determine how vasomotor tone and tissue pressure influence critical closing pressure and vascular resistance in isolated feline hind limb and kidney preparations.

December 31, 1958American Journal of Physiology-Legacy Content

Critical closing pressure and vasomotor tone in the hind leg and the kidney of the cat

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Determine how vasomotor tone and tissue pressure influence critical closing pressure and vascular resistance in isolated feline hind limb and kidney preparations.
Analyzed distal arterial pressure-time curves after arterial occlusion in isolated feline hind leg and kidney vascular beds.
Manipulated vascular resistance using electrical vasomotor nerve stimulation, intra-arterial noradrenaline, local blood cooling, tissue pressure changes, surgical denervation, and ganglionic blockade.
Arterial flow reached zero (< 0.0067 ml/min) after 2–3 minutes of occlusion at an arteriovenous pressure difference of 7.8 ± 4.5 mm Hg in the hind leg and 7.0 ± 3.6 mm Hg in the kidney.
Interventions that increased vascular resistance (nerve stimulation, noradrenaline, cooling, elevated tissue pressure) resulted in continuous pressure decay without reaching true critical closure during occlusion.
Interventions that reduced resistance (denervation, ganglionic blockade) permitted complete flow cessation at pressure levels lower than baseline control values.

Structured PICO

Population

Cats (isolated vascular beds of the hind leg and kidney)

Intervention

Alteration of resistance to flow via electrical stimulation of vasomotor nerves, intra-arterial injection of noradrenaline, lowering of temperature, increasing tissue pressure, denervation, and infusion of a ganglionic-blocking agent

Comparator

Normal conditions (control tests)

Outcome

Pressure-time curves and critical closing pressure (arterial pressure at zero arterial flow)surrogate

The study demonstrates that critical closing pressure is largely determined by vasomotor tone and tissue pressure, but its practical use as a measure of vasomotor tone is limited because zero arterial flow is only achieved under specific conditions.

Discussion

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Implication

Critical closing pressure should not guide vasomotor tone assessment in practice; leaves open its determinants in animal models.

Cite This Study

Yamada et al. (1958) studied this question.

synapsesocial.com/papers/6a8d1aac851ec846c20e5881 https://doi.org/10.1152/ajplegacy.1958.196.1.213

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Critical closing pressure and vasomotor tone in the hind leg and the kidney of the cat

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Critical closing pressure and vasomotor tone in the hind leg and the kidney of the cat

Key Points

Structured PICO

Discussion

Implication

Cite This Study

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