Indirect calorimetry in cardiac patients

Nineteen patients following open heart surgery were studied for the influence of cardiac function on metabolism. Diminished cardiac index was associated with the following changes in metabolism: lowering of the energy expenditure, an increase in respiratory quotient and conversion from fat to carbohydrate metabolism. Protein metabolism remained unaltered. The changes are attributed to decreased oxygen transport to the cell ('stagnant hypoxia'). For the estimation of energy expenditure without calorimetry assessment of cardiac function is essential. A formula for predicting resting energy expenditure is given.