PENTOXIPHYLLINE (PENT) AND HYPOTHERMIA (HT) REDUCE THE SUSCEPTIBILITY TO HYPOXIA IN ANESTHETIZED DOGS

Abstract

Hypothermia (HT) has been used to reduce O2 consumption (VO2) in critically ill children. HT, however, does not reduce the critical level of PaO2 required to maintain VO2, because cardiac output (CO) and O2 extraction (O2 ext) are also decreased. We hypothesized that PENT, by increasing RBC deformability and vasodilation, would increase CO and O2 ext during HT, reducing the critical levels of O2 delivery (DO2) and PaO2. 15 adult beagles were exposed to hypoxic hypoxia during normothermia (38°C), HT (30°C) and PENT plus HT. We measured Hb, %sat, pO2, CO, blood viscosity and VO2, and calculated DO2 (CO·CaO2), SVR, PVR, O2 ext and critical DO2 and PaO2. Because of its effects on CO and O2 ext, HT alone did not reduce critical PaO2. PENT reversed HT-induced changes in CO and O2 ext without changing VO2, allowing reductions in critical DO2 and PaO2. When combined, PENT and HT reduce the susceptibility to hypoxia in dogs by reducing VO2 while maintaining DO2 and O2 ext. PENT and HT may be useful in severe, intractable hypoxemia. Supported by HL 07633.