THE EFFECT OF MAJOR OPERATIONS ON HEART-RATE, RESPIRATORY RATE, PHYSICAL-ACTIVITY, TEMPERATURE AND RESPIRATORY GAS-EXCHANGE IN INFANTS

Perioperative changes in heart rate (HR), respiratory rate (RR), physi cal activity, body temperature, oxygen consumption (VO2), carbon dioxi de production (VO2)) and resting energy expenditure (REE) were studied in fourteen infants (weight 3.1 +/- 0.2 kg) who had a major operation . VO2 and VCO2 were measured by indirect calorimetry preoperatively, a nd postoperatively for the first 12 hours continuously and at 24 hours , 48 hours and 5 days. HR, RR and physical activity were recorded on a minute to minute basis, and rectal temperature was recorded hourly. R EE was calculated. HR, RR, VO2, VCO( )and REE increased postoperativel y, peaking at 2-4 hours, and returned to baseline levels by 12-24 hour s. In all of these variables, peak levels mere significantly higher th an Baseline levels (p < 0.001 for all variables). Physical activity an d rectal temperature did not vary significantly throughout the study. This study demonstrates that newborn infants exhibit a short-lived pos toperative increase in HR, RR, VO2, VCO2 and REE, which is not related to any alteration in physical activity or body temperature.