Chest
Clinical InvestigationsDependence of Oxygen Consumption on Oxygen Delivery in Patients with Chronic Congestive Heart Failure
Section snippets
METHODS
We studied eight patients with chronic stable CHF (NYHA functional class 3 or 4 for more than one year) despite conventional therapy (digitalis and diuretics). None of the patients had peripheral edema. Patients were admitted to the coronary intensive care unit for hemodynamic monitoring and further management of their heart failure. A 7.5-F Swan-Ganz balloon floatation catheter (Edwards Laboratories) was placed under fluoroscopic and/or pressure guidance in the pulmonary artery of each
RESULTS
Salient patient characteristics are shown in Table 1. Table 2 demonstrates mean physiologic data obtained at baseline and at peak oxygen delivery. All patients had normal arterial oxygenation. Body temperature was constant and normal at the times of gas exchange and hemodynamic measurements. There was a significant increase in , and after treatment with nitroglycerin, while all other parameters were unchanged. Figure 1 demonstrates the significant linear relationship
DISCUSSION
In most states of health and disease, any reduction in is compensated by local mechanisms that maintain constant and thereby fulfill the normal metabolic requirements of the tissues. The principal mechanism is increased oxygen extraction, which may be mediated by shifts in the oxyhemoglobin dissociation curve,9 or by changes in peripheral vasoregulation whereby blood flow is shifted to areas of high oxygen extraction.10 These mechanisms reduce and consequently
ACKNOWLEDGMENT
The authors would like to thank Dr. Andrew Wachtel and Ms. Elaine Mickle for their support in carrying out this project, and Ms. Debra Craig for secretarial assistance.
References (0)
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Manuscript received December 12; revision accepted March 2.