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. 1993 Dec;472:513–520. doi: 10.1113/jphysiol.1993.sp019959

Effect of positive and negative step changes in intrathoracic pressure on left ventricular function in conscious man.

S C De Cort 1, J A Innes 1, A Guz 1
PMCID: PMC1160499  PMID: 8145157

Abstract

1. Breathing affects left ventricular stroke volume (LVSV) in normal subjects. The observed relationship may result from interaction between the effects of changing lung volume and intrathoracic pressure (IP). 2. To investigate the effect of IP on LVSV with minimal changes in lung volume, beat-by-beat LVSV (pulsed Doppler ultrasound) and systemic blood pressure (Finapres) were measured during obstructed inspiratory and expiratory efforts causing step changes in IP of +/- 15 cmH2O for 10 s, in seven subjects. Changes in mouth pressure (MP) during airway occlusion were used to indicate changes in IP. Group-averaged data for each second were compared to that in the second before the change in MP using Dunnet's multiple range test. 3. Step reductions in MP resulted in immediate and significant falls in LVSV (P < 0.05) and systolic blood pressure (P < 0.01) and increased heart rate, although this was not significant. These responses were transient, lasting only 3 s despite 10 s of reduced MP. 4. Step increases in MP caused biphasic cardiovascular responses. LVSV increased immediately, then fell significantly below control after 8 s (P < 0.01). Heart rate increased significantly between 5 and 9 s after the onset of the increase in MP (P < 0.05), suggesting activation of the baroreflexes by the accompanying progressive fall in systolic blood pressure. 5. The asymmetry in time course and magnitude between the responses to positive and negative pressure may reflect asymmetrical effects of MP on systemic venous return, right ventricular output, pulmonary venous return and left ventricular (LV) after-load, with the baroreceptors limiting changes in arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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  1. Brinker J. A., Weiss J. L., Lappé D. L., Rabson J. L., Summer W. R., Permutt S., Weisfeldt M. L. Leftward septal displacement during right ventricular loading in man. Circulation. 1980 Mar;61(3):626–633. doi: 10.1161/01.cir.61.3.626. [DOI] [PubMed] [Google Scholar]
  2. Buda A. J., Pinsky M. R., Ingels N. B., Jr, Daughters G. T., 2nd, Stinson E. B., Alderman E. L. Effect of intrathoracic pressure on left ventricular performance. N Engl J Med. 1979 Aug 30;301(9):453–459. doi: 10.1056/NEJM197908303010901. [DOI] [PubMed] [Google Scholar]
  3. GREENFIELD J. C., Jr, PATEL D. J. Relation between pressure and diameter in the ascending aorta of man. Circ Res. 1962 May;10:778–781. doi: 10.1161/01.res.10.5.778. [DOI] [PubMed] [Google Scholar]
  4. Imholz B. P., van Montfrans G. A., Settels J. J., van der Hoeven G. M., Karemaker J. M., Wieling W. Continuous non-invasive blood pressure monitoring: reliability of Finapres device during the Valsalva manoeuvre. Cardiovasc Res. 1988 Jun;22(6):390–397. doi: 10.1093/cvr/22.6.390. [DOI] [PubMed] [Google Scholar]
  5. Innes J. A., De Cort S. C., Kox W., Guz A. Within-breath modulation of left ventricular function during normal breathing and positive-pressure ventilation in man. J Physiol. 1993 Jan;460:487–502. doi: 10.1113/jphysiol.1993.sp019483. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Innes J. A., Mills C. J., Noble M. I., Murphy K., Pugh S., Shore A. C., Guz A. Validation of beat by beat pulsed Doppler measurements of ascending aortic blood velocity in man. Cardiovasc Res. 1987 Jan;21(1):72–80. doi: 10.1093/cvr/21.1.72. [DOI] [PubMed] [Google Scholar]
  7. Jardin F., Farcot J. C., Gueret P., Prost J. F., Ozier Y., Bourdarias J. P. Cyclic changes in arterial pulse during respiratory support. Circulation. 1983 Aug;68(2):266–274. doi: 10.1161/01.cir.68.2.266. [DOI] [PubMed] [Google Scholar]
  8. Kurki T., Smith N. T., Head N., Dec-Silver H., Quinn A. Noninvasive continuous blood pressure measurement from the finger: optimal measurement conditions and factors affecting reliability. J Clin Monit. 1987 Jan;3(1):6–13. doi: 10.1007/BF00770876. [DOI] [PubMed] [Google Scholar]
  9. Molhoek G. P., Wesseling K. H., Settels J. J., van Vollenhoven E., Weeda H. W., de Wit B., Arntzenius A. C. Evaluation of the Penàz servo-plethysmo-manometer for the continuous, non-invasive measurement of finger blood pressure. Basic Res Cardiol. 1984 Sep-Oct;79(5):598–609. doi: 10.1007/BF01910489. [DOI] [PubMed] [Google Scholar]
  10. OPDYKE D. F., BRECHER G. A. Effect of normal and abnormal changes of intrathoracic pressure on effective right and left atrial pressures. Am J Physiol. 1950 Mar;160(3):556–566. doi: 10.1152/ajplegacy.1950.160.3.556. [DOI] [PubMed] [Google Scholar]
  11. Robotham J. L., Lixfeld W., Holland L., MacGregor D., Bryan A. C., Rabson J. Effects of respiration on cardiac performance. J Appl Physiol Respir Environ Exerc Physiol. 1978 May;44(5):703–709. doi: 10.1152/jappl.1978.44.5.703. [DOI] [PubMed] [Google Scholar]
  12. Santamore W. P., Lynch P. R., Meier G., Heckman J., Bove A. A. Myocardial interaction between the ventricles. J Appl Physiol. 1976 Sep;41(3):362–368. doi: 10.1152/jappl.1976.41.3.362. [DOI] [PubMed] [Google Scholar]
  13. Scharf S. M., Brown R., Saunders N., Green L. H. Effects of normal and loaded spontaneous inspiration on cardiovascular function. J Appl Physiol Respir Environ Exerc Physiol. 1979 Sep;47(3):582–590. doi: 10.1152/jappl.1979.47.3.582. [DOI] [PubMed] [Google Scholar]

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