Effect of tension and timing of contraction on the blood flow of the diaphragm
- 1 June 1983
- journal article
- research article
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 54 (6), 1597-1606
- https://doi.org/10.1152/jappl.1983.54.6.1597
Abstract
An open-chest animal model was developed to study the diaphragmatic blood flow (.ovrhdot.Qdi) during bilateral electrophrenic stimulation. Two patterns of stimulation were used, continuous and intermittent, and both patterns were held at various transdiaphragmatic pressures (Pdi). The contractions were nearly isometric and held at an initial length of supine functional residual capacity (FRC). .ovrhdot.Qdi was measured in 6 dogs by catheterizing a branch of the diaphragmatic vein and by counting the blood drops with an infrared cell. During continuous contractions .ovrhdot.Qdi increased as a function of Pdi up to 70 .+-. 12 ml .cntdot. 100 g-1 .cntdot. min-1 at 20% Pdimax. At higher levels .ovrhdot.Qdi decreased progressively and approached zero at 75% of Pdimax. A postcontraction hyperemia occurred at Pdi values greater than 20% Pdimax and increased as a function of Pdi. During intermittent contractions .ovrhdot.Qdi was a unique function of the diaphragmatic tension-time index (TTdi), a product of Pdi times the duty cycle (contraction time/total cycle time). .ovrhdot.Qdi increased progressively up to a TTdi of 25% Pdimax and decreased above that point toward zero at TTdi of 80% Pdimax. The postcontraction hyperemia appeared at a TTdi of .apprx. 15% of Pdimax and increased as a function of TTdi. .ovrhdot.Qdi is limited beyond a TTdi of .apprx. 20% Pdimax, as indicated by the increase in postcontraction hyperemia, and that .ovrhdot.Qdi is a function of both Pdi and the timing of contraction.This publication has 14 references indexed in Scilit:
- Diaphragmatic blood flow and energy expenditure in the dog. Effects of inspiratory airflow resistance and hypercapnia.JCI Insight, 1976
- The influence of varying oxygen tensions in inspired gas on133Xenon muscle clearance and fatigue levels during sustained and dynamic conctractionsEuropean Journal of Applied Physiology, 1975
- The ability to sustain great breathing effortsRespiration Physiology, 1968
- Local and central circulatory responses to sustained contractions and the effect of free or restricted arterial inflow on post‐exercise hyperaemiaThe Journal of Physiology, 1967
- The blood flow through active and inactive muscles of the forearm during sustained hand‐grip contractionsThe Journal of Physiology, 1963
- Relation Between Blood Flow and Contraction Force in Active Skeletal MuscleCirculation Research, 1962
- THE RELATIONSHIP OF OXYGEN COST OF BREATHING TO RESPIRATORY MECHANICAL WORK AND RESPIRATORY FORCEJCI Insight, 1961
- Voluntary strength and fatigueThe Journal of Physiology, 1954
- The blood flow through the human calf during rhythmic exerciseThe Journal of Physiology, 1949
- The blood flow through muscle during sustained contractionThe Journal of Physiology, 1939