A predictive model for the clearance of soluble phospholipase A2 during septic shock.

Circulating phospholipase A2 (PLA2) has been recognized as a mediator of cardiovascular collapse in septic shock. Proximal mediators of endotoxemia, including tumor necrosis factor and interleukin 1, induce PLA2 synthesis and release, but the factors regulating PLA2 elimination are unknown. Similarly, the kinetics of PLA2 clearance during recovery from septic shock have not been examined. An autoregressive mathematical model was developed to describe the rate of PLA2 clearance during the recovery phase of septic shock. This model (which estimates that the current day's PLA2 level is 77% of the previous day's level), accounted for 89% of the variability seen in the data. The estimated circulating half-life of soluble PLA2 in septic shock in man was 32 hours. Since elevation in serum PLA2 activity is closely associated with bacteremia or endotoxemia, a significant deviation from predicted PLA2 values may denote impending relapse.