Hepatosplanchnic and peripheral tissue oxygenation during treatment of hemorrhagic shock: The effects of pentoxifylline administration

Objective To evaluate the effects of pentoxifylline (PF) administration on liver, gut , and peripheral oxygenation during crystalloid resuscitation of hemorrhagi c shock. Summary Background Data Hypoperfusion of the hepatosplanchnic vascular bed and hypoxia of vital org ans may be prolonged despite adequate therapy of hemorrhagic shock. Vasocon striction, leukostasis, platelet aggregation, and red blood cell plugging c ould be the underlying causes. PF has been shown to counteract these effect s, but its effects in a large animal shock model have been less studied, Methods Thirteen anesthetized piglets (mean weight 19.6 kg) were bled steadily to a mean arterial pressure (MAP) of 40 to 50 mmHg and a 70% reduction in cardi ac output during 1 hour. These levels were maintained for an additional hou r. The animals were resuscitated with acetated Ringer's solution according to MAP and cardiac output values and followed for 80 minutes (total 3 hours and 20 minutes). Seven piglets were given PF boluses (12.5 mg/kg) and infu sion (0.2 mg/kg.min), and the rest (n = 6) served as controls. Hemodynamic and systemic oxygen transport variables were recorded. Liver parenchymal an d peripheral tissue (subcutaneous, transcutaneous, conjunctival) oxygen ten sions (P-O2) were measured continuously with polarographic electrodes. Jeju nal intramucosal pH (pHi) was calculated every hour by the luminal P-CO2, o btained with a balloon tonometer, and arterial bicarbonate concentration. Results Cardiac output decreased by a mean of 76% during shock and was restored dur ing resuscitation in both groups. MAP decreased from 110 to 40 mmHg but rem ained at 70 to 80 mmHg during resuscitation in both groups despite remarkab le volume load (2.6 ml/min per kg). Liver parenchymal P-O2 decreased from 2 9 +/- 1 to 15 +/- 1 mmHg during shock and inc;eased to 36 +/- 2 mmHg in the PF group, whereas in control group it remained at 26 mmHg. The difference between groups was significant, but at the end of follow-up the liver P-O2 decreased to 21 mmHg in both groups. Gut pHi, peripheral tissue oxygen tens ions, and the plasma adrenaline and noradrenaline concentrations did not di ffer between the groups. Conclusions Pentoxifylline improved specifically, although only transiently, liver tiss ue oxygenation. Perhaps;the microvascular abnormalities after resuscitation of hemorrhagic shock are more prominent in the hepatic vascular bed, rende ring PF specifically effective in that area. The lack of any effect of PF o n gut and peripheral tissue oxygenation may have resulted from the persiste nt vasoconstriction and inadequate restoration of blood volume with crystal loid solution.