| Popis: |
We addressed the impact on intracranial pressure (ICP) of posthemorrhage fluid resuscitation with a protocol in which additional fluid was infused to maintain a stable cardiac output after an initial bolus of fluid was infused. Anesthetized, mechanically ventilated mongrel dogs (n = 27) underwent a 30-minute interval of hemorrhagic shock (mean arterial pressure = 55 mm Hg) during which inflation of a subdural balloon maintained ICP at 15 mm Hg. After shock, animals were resuscitated with one of four randomly assigned fluids: (1) slightly hypotonic crystalloid (Na+, 125 mEq.L-1; designated Na-125); (2) hypertonic crystalloid (Na+, 250 mEq.L-1; designated Na-250); (3) slightly hypotonic crystalloid plus 10% pentastarch (Na-125P); or (4) hypertonic crystalloid plus 10% pentastarch (Na-250P). Supplemental fluid was administered as needed to maintain cardiac output comparable to baseline values. ICP increased progressively in all fluid groups during resuscitation. Cerebral blood flow, measured by the cerebral venous outflow method, increased immediately after resuscitation and then declined steadily over time in all groups. Fluids containing pentastarch maintained hemodynamic stability with minimal supplementation throughout most of the postresuscitation period, compared with crystalloid alone, which required substantial additional volume. If decreased intracranial compliance and hemorrhage are combined, ongoing resuscitation is associated with significantly increased ICP and significantly decreased cerebral blood flow, independent of the tonicity and oncotic pressure of the infused fluid. |
