Impact of ICP instability and hypotension on outcome in patients with severe head trauma

Abstract

✓ This study describes the relationship between raised intracranial pressure (ICP), hypotension, and outcome from severe head injury. The study is based on information derived from the Traumatic Coma Data Bank where ICP records from a relatively large number of patients were available to help delineate the major factors influencing outcome. From the total data base of 1030 patients, 428 met minimum monitoring duration criteria for inclusion in the present analysis. Outcome was classified according to the Glasgow Outcome Scale score determined at 6 months postinjury. Arrays of comparably defined summary measures describing the patient's course were considered for ICP, blood pressure (BP), central perfusion pressure, and therapy intensity level. For instance, the array of ICP summary descriptors included the proportion of ICP readings greater than x, for x = 0 to 80 mm Hg by increments of 5 mm Hg. A total of 187 candidate summary descriptors were considered. A stepwise ordinal logistic regression was used to select the subset of candidate summary descriptors that best explained the 6-month outcome. As established previously, age, admission motor score, and abnormal pupils were each highly significant in explaining outcome. Beyond these factors, the proportion of hourly ICP readings greater than 20 mm Hg was next selected and was also highly significant in explaining outcome (p < 0.0001). In addition to the ICP factor, the cutoff point of 20 mm Hg was selected by the procedure as most indicative of outcome. With these four factors modeled, the next selected factor was the proportion of hourly BP readings less than 80 mm Hg. Again, the BP factor was highly significant in explaining outcome (p < 0.0001). As with the ICP factor, the BP cutoff point of 80 mm Hg was objectively selected as most indicative of outcome. In summary, the incidence of mortality and morbidity resulting from severe head trauma is strongly related to raised ICP and hypotension measured during the course of ICP management. Moreover, these ICP and BP factors provide a better indication of outcome than the similarly defined factors of central perfusion pressure or therapy intensity level.

Specialist neurocritical care and outcome from head injury

“…Prominent amongst these changes are the regular monitoring and control of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) [2]. While these have not been subjected to randomised controlled trials, they are based on physiological principles [3,4,5,6], and the association of poor outcomes with physiological derangements after head injury [3,4,5,6]. Despite these findings and the fact that ICP monitoring is recommended by well disseminated guidelines [7,8], recent surveys report that less than 50% of patients with severe head injury have ICP monitoring in European centres, and hence do not receive ICP/CPP directed therapy [9,10].…”

Cerebral perfusion pressure and intracranial pressure in relation to neuropsychological outcome

“…The prognostic value of secondary insults due to reduced MAR increased ICR and reduced CPP has been thoroughly examined and several outcome studies have demonstrated the adverse effect of raised ICP on mortality [4][5][6][7]. Reduced CPP was also found to be strongly correlated with mortality [8].…”

A Portable CT Scanner in the Pediatric Intensive Care Unit Decreases Transfer-Associated Adverse Events and Staff Disruption

“…Over 70% of intrahospital transfers are reported as being associated with unexpected events, either equipment-or patient-related [6,7], and our findings (75%) are certainly agreeable with this. Children requiring neurocritical care are at particular higher risks with transfer, as urgent head scans are performed during periods of severe physiological instability, to diagnose or rule out a severe complication such as expanding intracranial hematoma or acute hydrocephalus [8,9]. Traditionally, scans necessitate the transfer of these children with possibly impending cerebral herniation outside the PICU environment, with multiple monitoring, infusions, and ventilation, all requiring transfer to suboptimal transport modes.…”