Oxygen consumption in the early postinjury period: Use of continuous, on-line indirect calorimetry

Objective: To determine the patterns of oxygen consumption (V) over dot o(2 ) using indirect calorimetry (IC) for the first 24 hrs after serious blunt traumatic injury. Design: Prospective, observational study. Setting: Surgical intensive care unit of a Level 1 trauma center, Patients: Sixty-six mechanically ventilated patients with blunt traumatic i njury and Injury Severity Score >15. Interventions: IC for 24 hrs postinjury. Patients were resuscitated to stan dard parameters of perfusion. Measurements and Main Results: Mean patient age was 50.1 +/- 18.7 yrs with a mean Injury Severity Score 30.7 +/- 11,3). Mean (V) over dot o(2) for all patients for the 24-hr study period was 168.5 +/- 29.5 mL/min/m(2). The le vel of (V) over dot o(2), was not related to Injury Severity Score, the num ber or combination of organ systems injured, or to the use of vasoactive ag ents. Patients >65 yrs of age had significantly lower (V) over dot o(2) (p = .0038) compared with patients less than or equal to 50 yrs, (V) over dot o(2) did not change over time after resuscitation to normal parameters of p erfusion, Mean (V) over dot o(2) was 156.5 +/- 63.2 mL/min/m(2) in patients who developed multiple organ dysfunction, and 172.4 +/- 33.3 mL/min/m(2) i n those who did not develop multiple organ dysfunction (p = .16), Conclusions: Seriously injured patients are hypermetabolic in the early pos tinjury period, The level of ire, is unrelated to injury severity or number of organ systems involved. Elderly patients can be expected to have lower levels of (V) over dot o(2) does not change significantly in response to re suscitation to normal parameters of perfusion, (V) over dot o(2) measured b y IC did not predict the development of multiple organ dysfunction.