P 50 in burn injury

P50, 2,3-diphosphoglycerate (DPG), inorganic phosphorus (Pi), adenosine triphosphate (ATP), and blood gases were measured daily in 23 patients with burn injuries, until their death or discharge from the ICU. At the time of admission, P50 values were high. In nonsurvivors, P50 started to decline 1 week after the injury. Corrected P50 values to pH 7.4 were well correlated with DPG values. In survivors, P50 tended to correlated with Pi values, but in nonsurvivors at the septic or terminal stage, the values P50 did not correlate with Pi or ATP. Low P50 predicted the poor outcome of severely burned patients. At the convalescent stage of major burn injury, P50 and DPG were higher than normal and often remained elevated for weeks.