Effect of Sedation on Oxygen Consumption of Children Undergoing Cardiac Catheterization

A study of oxygen consumption following sedation was performed in cardiovascular patients between 1 month and 5½ years of age. Oxygen consumption fell in all 17 subjects during cardiac catheterization (average fall 34%). Four of these children underwent a second study with similar sedation but without catheterization, and all demonstrated a fall in oxygen consumption (average fall 25.9%). This drop was particularly marked in the younger children. The change in oxygen consumption following sedation followed a roughly consistent pattern, reaching a minimum in ½ to 2 hours (generally shortly after the cardiac catheter was introduced into a blood vessel) and returning to control levels as blood was sampled and the procedure was completed. Thus, when using cardiac catheterization and the Fick principle to calculate cardiac output, simultaneous measurement of oxygen consumption and blood sampling is essential to obtain accurate results in the sedated child.