Hemodynamic effects of cardiac cycle-specific increases in intrathoracic pressure

M. R. Pinsky, G. M. Matuschak, L. Bernardi, M. Klain

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

Changes in intrathoracic pressure (ITP) can influence cardiac performance by affecting ventricular loading conditions. Because both systemic venous return and factors determining left ventricular (LV) ejection may vary over the cardiac cycle, phasic increases in ITP may differentially affect preload or afterload if delivered at specific points within the cardiac cycle. We studied the hemodynamic effects of cardiac cycle-specific increases in ITP (pulses) delivered by a high-frequency jet ventilator in an acute closed-chested canine model (n = 11), using electromagnetic flow probes to measure biventricular stroke volume. Measurements were taken during a control condition and after the induction of acute ventricular failure (AVF) by propranolol hydrochloride and volume infusion. ITP was independently varied without changing lung volume by the inflation of thoracoabdominal binders. Although synchronous pulses had minimal hemodynamic effects in unbound controls, binding pulses timed to occur in early diastole resulted in decreases in LV filling pressure and left ventricular stroke volume (SV(lv)) (P <0.05). In the AVF condition, pulses increased LV performance, evidenced by increases in SV(lv) (P <0.01), despite decreases in LV filling pressure (P <0.05). This effect is maximized by binding and by timing the pulses to occur in systole. We conclude that cardiac cycle-specific increases in ITP can significantly affect cardiac performance. These effects appear to be related to the ability of such timed pulses to selectively affect LV preload and afterload.

Original languageEnglish
Pages (from-to)604-612
Number of pages9
JournalJournal of Applied Physiology
Volume60
Issue number2
Publication statusPublished - 1985

Fingerprint

Hemodynamics
Pressure
Ventricular Pressure
Stroke Volume
Diastole
Systole
Electromagnetic Phenomena
Economic Inflation
Mechanical Ventilators
Propranolol
Canidae
Thorax
Blood Pressure
Lung

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Pinsky, M. R., Matuschak, G. M., Bernardi, L., & Klain, M. (1985). Hemodynamic effects of cardiac cycle-specific increases in intrathoracic pressure. Journal of Applied Physiology, 60(2), 604-612.

Hemodynamic effects of cardiac cycle-specific increases in intrathoracic pressure. / Pinsky, M. R.; Matuschak, G. M.; Bernardi, L.; Klain, M.

In: Journal of Applied Physiology, Vol. 60, No. 2, 1985, p. 604-612.

Research output: Contribution to journalArticle

Pinsky, MR, Matuschak, GM, Bernardi, L & Klain, M 1985, 'Hemodynamic effects of cardiac cycle-specific increases in intrathoracic pressure', Journal of Applied Physiology, vol. 60, no. 2, pp. 604-612.
Pinsky, M. R. ; Matuschak, G. M. ; Bernardi, L. ; Klain, M. / Hemodynamic effects of cardiac cycle-specific increases in intrathoracic pressure. In: Journal of Applied Physiology. 1985 ; Vol. 60, No. 2. pp. 604-612.
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