[Energy metabolism and energy consumption of intensive care patients on respirators]

There are two main reasons for assessing energy turnover individually and as accurately as possible; firstly, the marked variation in available data on the degree to which energy turnover increases after severe trauma, and secondly accumulating evidence of the potential dangers of an inappropriately high so-called "hypercaloric" substrate dosage, which exceeds energy requirements. The energy turnover of 50 polytraumatized intensive care patients was therefore measured by indirect calorimetry and compared with norm values. Comparison of the median values revealed an approximately 50% higher energy turnover in the polytraumatized cases than calculated basal levels. The median values of our patients all lay within a similar range, but for each individual case we found marked differences between the energy turnover as measured by indirect calorimetry, and that estimated from norm tables. The oxygen consumption and CO2 production rates of 10 polytraumatized ventilated patients, measured at short time intervals, showed only minimal variations during the course of 24 h. The separate measurements carried out at hourly intervals varied by less than 10% when compared to an 1-h period of observation between 11 and 12 a.m. The oxygen consumption of a group of 40 polytraumatized, ventilated intensive care patients receiving various different i.v. infusions and parenteral nutrition regimens was, with an average of 382 +/- 47 ml/min, much higher than physiologically normal values. The energy turnover rate of these patients was correspondingly much higher than that of a fit person at rest, despite the fact that the rates measured were relatively low when compared to values found in the older literature.(ABSTRACT TRUNCATED AT 250 WORDS)