Key Points
- To examine how reduced regional blood flow alters the competitive balance between sympathetic vasoconstrictor control and local metabolic vasodilation across resistance and capacitance vessels in skeletal muscle.
- Evaluated vascular resistance and capacitance responses to sympathetic vasoconstrictor nerve stimulation and close intraarterial l-noradrenaline infusion across varying severities of reduced skeletal muscle blood flow.
- Tracked changes in precapillary and postcapillary resistance alongside alterations in mean capillary hydrostatic pressure and net transcapillary fluid movement.
- Blood flow reduction progressively impaired and ultimately abolished resistance and capacitance responses, with resistance responses declining more rapidly and completely; higher stimulation frequencies and noradrenaline doses conferred temporary protection, particularly to capacitance responses.
- Precapillary resistance deteriorated earlier and to a greater extent than postcapillary resistance, eliminating the normal nerve-mediated drop in capillary hydrostatic pressure and shifting fluid movement from inward absorption to outward transcapillary filtration.
Structured PICO
PPopulationSkeletal muscle model
IInterventionSympathetic vasoconstrictor nerve fibre activation and close intraarterial infusion of l-noradrenaline during regional blood flow reduction
OOutcomeResponses of resistance and capacitance vessels and capillary filtrationsurrogate
Precapillary resistance vessels are more influenced by local dilating metabolic factors, whereas postcapillary vessels are more dominated by extrinsic nervous factors, which may explain circulatory derangements in shock.