Secondary insults in subarachnoid hemorrhage: occurrence and impact on outcome and clinical deterioration.

OBJECTIVE: To study the occurrence of secondary insults during neurointensive care of patients with subarachnoid hemorrhage using a computerized multimodality monitoring system and to study the impact of secondary insults on clinical deterioration and functional outcome.
METHODS: Patients with subarachnoid hemorrhage who were admitted to the neurointensive care unit between January 1999 and December 2002 with at least 120 hours of multimodality monitoring data within the first 240 hours of neurointensive care were included. Data were continuously recorded for intracranial pressure (ICP), cerebral perfusion pressure (CPP), mean arterial blood pressure, systolic blood pressure, oxygen saturation, and temperature. Secondary insult levels were defined as ICP of 20 or greater or 25 or greater; CPP of 60 or lower, 55 or lower, greater than 100, or greater than 110; mean arterial blood pressure of 80 or lower, 70 or lower, 120 or greater, or 130 or greater; systolic blood pressure of 110 or lower, 100 or lower, 180 or greater, or 200 or greater; temperature of 38 degrees C or higher or 39 degrees C or higher; and oxygen saturation of less than 95 or less than 90. Secondary insults were quantified as the proportion of good monitoring time at the insult level. Uni- and multivariate logistic regression analyses were performed with admission and secondary insult variables as explanatory variables and clinical deterioration and independent outcome as the dependent variable, respectively.
RESULTS: Ninety-nine patients (67 women; mean age, 57.8 yr) met the inclusion criteria. In the univariate analysis, ICP of 20 or greater, ICP of 25 or greater, CPP of 60 or less, and CPP of 55 or less increased the risk of clinical deterioration, whereas CPP greater than 100 and systolic blood pressure greater than 180 decreased the risk of clinical deterioration. In the multivariate logistic regression, ICP of 25 or greater and CPP of greater than 100 had an independent effect on clinical deterioration. The occurrence of secondary insults had no significant effect on functional outcome.
CONCLUSION: Elevated ICP not responding to treatment is predictive of clinical deterioration, whereas high CPP decreases the risk of clinical deterioration. It may be beneficial to not lower spontaneous high CPP in patients with subarachnoid hemorrhage.