The effects of airway pressure on cardiac function in intact dogs and man.

Rankin, J S; Olsen, Craig O.; Arentzen, C. E.; Tyson, G. S.; Maier, G. W.; Smith, Peter K.; Hammon, John W.; Davis, Jean; Modesti, Pietro Amedeo; Anderson, R. W.; Sabiston, David C.

doi:10.1161/01.cir.66.1.108

Cited by 142 publications

(48 citation statements)

References 23 publications

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“…9 Despite some conflicting results,13 the majority of authors on this subject' 2, 9, 14 believe that lung inflation increases the left and reduces the right ventricular stroke output. But, as inflation progresses, left ventricular stroke output decreases secondarily as a result of reduced right ventricular stroke output, which is followed by left ventricular stroke output after a phase lag of 1 In accord with previous studies9 1, 14 the inspiratory reduction in pulmonary arterial flow observed in this study was followed after a phase lag of 2 beats by a reduction in systemic arterial flow, which began at the end of inhalation and was consequently pronounced during exhalation. Thus, reversed pulsus paradoxus FIGURE 7.…”

Section: Resultssupporting

confidence: 92%

Cyclic changes in arterial pulse during respiratory support.

Jardin¹,

Farcot²,

Guéret³

et al. 1983

Circulation

224

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In 13 patients on respiratory support we combined two-dimensional echocardiography with hemodynamic monitoring to determine the mechanism of cyclic changes in arterial pulse, defined as an inspiratory rise in radial artery pulse pressure. Beat-to-beat evaluation of cardiac performance was obtained during the following three distinct consecutive phases of the controlled respiratory cycle: exhalation (phase I), preinspiratory pause (phase LI), and lung inflation (phase III). Airway pressure, left ventricular filling pressure (i.e., pulmonary capillary wedge minus esophageal pressure), and pulmonary artery and radial artery pressures were simultaneously recorded during mechanical ventila-'tion along with beat-to-beat two-dimensional echocardiographic left ventricular end-systolic and enddiastolic dimensions. From a reference value for pulmonary artery and radial artery pulse contour obtained during a brief period of imposed apnea, beat-to-beat measurements of left and right ventricular stroke output were also performed during the controlled respiratory cycle with the pulse contour method. Cyclic changes in arterial pulse appeared to result directly from a transitory increase in left ventricular stroke output during lung inflation (41.4 + 14.6 ml/m2), whereas right ventricular stroke output exhibited a steep fall (31.7 ± 12.4 ml/m2) at this time. An opposite variation was also observed during exhalation, during which a fall in left ventricular stroke output (31.9 ± 11.2 mI/i2) was accompanied by a rise in right ventricular stroke output (38.6 11.9 ml/m2). Both stroke outputs reached an identical level during preinspiratory pause (37.4 + 14. 1 ml/m2 for left ventricle and 39.1 ±-13.8 ml/m2 for right ventricle

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Section: Resultssupporting

confidence: 92%

Cyclic changes in arterial pulse during respiratory support.

Jardin¹,

Farcot²,

Guéret³

et al. 1983

Circulation

224

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“…Rankin et al (7) examined the mechanical and d@ensional changes that occur in the dog heart during change in Paw and found that increases in Paw decrease preload in the left ventricle which reduces stroke volume. They hypothesized that the reduction in left ventricular preload was due to a decrease in blood flow through the lungs caused by an increase in PVR.…”

Section: Resultsmentioning

confidence: 99%

Impairment of Hemodynamics with Increasing Mean Airway Pressure during High-Frequency Oscillatory Ventilation

et al. 1988

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ABSTRACT. We investigated the effects of changes in mean airway pressure (Paw), oscillatory frequency and lung compliance on cardiac output (CO) and pulmonary vascular resistance in seven adult cats (3.0 f 0.6 kg) during highfrequency oscillatory ventilation (HFOV). The cats were anesthetized with chloralose and urethane and ventilated with a high-frequency oscillator at Paw of 4,8,12, and 16 cm H,O and frequencies of 3,6, 12,16, and 20 Hz. Saline lavage was used to reduce lung compliance. CO was continuously recorded with an electromagnetic flow probe placed around the aorta and pulmonary vascular resistance was calculated from left atrial and pulmonary artery pressures. Lung lavage reduced static compliance of the respiratory system but did not change CO during pressurelimited ventilation. During HFOV, CO was higher in animals after lung lavage at each Haw. As Haw was raised from 4 to 16 cm H,O during HFOV, CO decreased from 133 f 36 to 87 f 31 ml/min kg in animals with normal lungs and decreased from 153 f 33 to 107 f 19 ml/min kg after lung lavage (both p < 0.001). Increasing Haw was also associated with an increase in pulmonary vascular resistance both before and after lung lavage (both p < 0.005). Changes in frequency did not significantly alter CO or pulmonary vascular resistance. We conclude that the interaction between t h e heart and lungs during HFOV is largely mediated by Paw and compliance of the respiratory system. Furthermore, regardless of the degree of lung compliance, cardiac function may be impaired during HFOV as Paw is elevated. (Pediatr Res 23:628-631,1988) Abbreviations CO, cardiac output HFOV, high-frequency oscillatory ventilation -Paw, mean airway pressure PVR, pulmonary vascular resistance Assisted ventilation has substantially reduced mortality in infants with respiratory failure. Unfortunately this reduced mortality has been accompanied by an increase in major complications such as air leaks and bronchopulmonary dysplasia. Inasmuch as these side effects are heavily influenced by certain Received November 30, 1987; accepted February 10, 1988 ventilatory parameters, especially airway pressures (1, 2), new ventilators that enhance gas exchange while minimizing pressure delivery have been developed.HFOV, delivers and withdraws small stroke volumes at very high frequencies. Because HFOV may enable adequate gas exchange to occur at reduced pressure swings, it may alleviate some of the complications of assisted ventilation, However, oxygenation during HFOV is largely dependent on Paw (3,4). Inasmuch as increasing Paw has been shown to depress CO (5-7), oxygen transport may be reduced despite an increase in arterial oxygenation.Because the effect of Faw on cardiovascular function is dependent on the transpulmonary pressure, decreased lung compliance is thought to be associated with less impairment of CO. However, CO is difficult to assess in small infants and often blood pressure and heart rate are the only available means of assessing cardiovascular function. As a result, it remains un...

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“…In both ventricles, systolic dimensional shortening correlated with measured stroke volume (figure 2) and regional stroke work correlated with global stroke work (figure 3) before and after ischemia. The mean slope and x intercept of equation 5 relating stroke volume to dimensional shortening and of equation 6 figure 6. Left ventricular developed pressure increased and systolic dimensional shortening decreased at a given end-diastolic length compared with control ( figure 6, A).…”

Section: Resultsmentioning

confidence: 99%

Quantification of the contractile response to injury: assessment of the work-length relationship in the intact heart.

Morris¹,

Pellom²,

Murphy³

et al. 1987

Circulation

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We used a sonomicrometric determination of ventricular dimension to examine the effect of ischemia and reperfusion on the work-length relationship in the intact heart to develop a useful and precise variable of ventricular contractile response to injury. Twenty anesthetized dogs were instrumented with epicardial ultrasonic dimension transducers to record right ventricular free wall chord length and left ventricular minor-axis length, micromanometers to record ventricular pressures, and an electromagnetic probe to record pulmonary arterial (n = 8) or aortic (n = 7) flow. Dogs were subjected to either 20 min (n = 7) or 30 min (n = 13) of global cardiac ischemia supported by cardiopulmonary bypass. Data were acquired over a range of end-diastolic volumes produced by transient (5 to 10 sec) vena caval occlusion before and after ischemia. In both ventricles, systolic epicardial dimensional shortening correlated with flow probe-measured stroke volume (mean r = .969) and regional stroke work calculated as the integral of instantaneous ventricular pressure and epicardial dimension correlated with measured global stroke work (mean r = .960), confirming the validity of dimensional measurements. Regression analysis demonstrated a highly linear relationship between calculated regional stroke work and end-diastolic length in the right ventricle (mean r = .973) and left ventricle (mean r = .967), quantifiable by a slope (Mw) and x intercept (Lw). Change in afterload produced by pulmonary arterial or aortic constriction resulted in no significant changes in Mw or Lw in either ventricle. Ischemia and reperfusion decreased Mw and shifted Lw to the right in both ventricles. The decrease in MW with 30 min ischemia exceeded the decrease with 20 min ischemia by 29% in the right ventricle and by 32% in the left (p < .04) with up to 1 hr of reperfusion. Changes in Lw were not related to severity of injury. After ischemia, infusion of calcium increased Mw by 177% in the right ventricle and by 67% in the left (p < .03) without significant changes in Lw. Independent of load conditions, the slope, Mw, of the linear stroke work vs end-diastolic length relationship is a valid and precise index of right and left ventricular contractile response to global ischemia in the intact circulation. This variable may be useful in evaluating therapies designed to limit myocardial injury and enhance ventricular functional performance. Circulation 76, No. 3, 717-727, 1987

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The effects of airway pressure on cardiac function in intact dogs and man.

Cited by 142 publications

References 23 publications

Cyclic changes in arterial pulse during respiratory support.

Cyclic changes in arterial pulse during respiratory support.

Impairment of Hemodynamics with Increasing Mean Airway Pressure during High-Frequency Oscillatory Ventilation

Quantification of the contractile response to injury: assessment of the work-length relationship in the intact heart.

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