Systemic vascular responses to increased intracranial pressure. 1. Effects of progressive epidural ballon expansion on intracranial pressure: and systemic circulation.

This paper details the results of experimental studies, on 16 dogs with artificially-induced intracranial space-occupying lesions, of the systemic vascular responses and the intracranial pressure changes (both in the supratentorial and infratentorial compartments) induced by increasing intracranial pressure. The changes produced were divided into two phases such that phase 1 detailed the alterations observed from the start of the balloon inflation up to the initiation of the systemic pressor response. Phase 2 recorded those alterations which occurred during, and immediately after, the period of systemic hypertension (see Fitch et al., 1977). The changes observed during phase 1, and presented in this communication, were those of increasing intracranial pressures and decreasing mean arterial pressure and heart rate. These alterations were associated with decreases in supratentorial perfusion pressure and increases in transtentorial pressure gradient and arrhythmia index.