Cerebral Perfusion Pressure (CPP) Management Information Feedback and Nursing

Overview

The aim of the initial proposal was to evaluate, in the context of optimal medical management, the impact of a bedside system of cerebral perfusion pressure (CPP) information feedback on nursing moment-to-moment management of CPP, and the relationship of that management to patient functional outcome at discharge, 3 and 6 months. The primary hypothesis being tested is that Glasgow Outcome Score (GOS) 6 months post acute care discharge will be significantly better in those monitored with the continuous CPP display. In the second phase of the study the adult study will be extended to children to determine if there is a critical threshold for CPP in children following brain injury based on their outcome at 3, 6, and 12 months. The primary outcome measure is the GOS at 12 months post-injury. The GOS, Behavior Rating Inventory of Executive Function, and PedsQOL will also be assessed at 3, 6, \& 12 months, and the Adaptive Behavior Assessment System at 3 and 6 months post-injury. In addition, the researchers will examine variability and complexity of physiologic measures, such as blood pressure, recorded during the intensive care unit stay of adults and children enrolled in the study. The researchers will study the association of these measures with risk for secondary brain injury and ability to predict differences in outcome. The researchers will also assess the value individuals place on varying outcomes following brain injury.

Prevention or reduction of secondary brain injury is a key component in the critical care management of patients with a variety of brain insults. Current clinical management emphasizes maintaining cerebral perfusion pressure (CPP) at or above 70 mm Hg to minimize such secondary brain injury. However, due to poor ergonomics in clinical monitoring displays it is likely that short episodes of decreased CPP are missed by attending nurses in the course of necessary patient repositioning, suctioning, and other routine therapeutic activities. Given the crucial role of neuronal perfusion in preventing secondary injury beyond that of the original brain insult, refining the nurse's ability to visualize and manage CPP on a moment-to-moment basis may allow measurable improvement in short and long-term patient functional outcome. Computer interfaces that provide highly visible information about CPP will be randomly allocated to intensive care unit beds of patients with closed head injury (CHI) or subarachnoid hemorrhage (SAH) in whom intracranial pressure monitors and arterial lines have been placed for medical management, stratified by primary diagnosis (CHI or SAH) and severity. Continuous data will be collected from 150 patients with and 150 patients without the interface monitor for the duration of CPP monitoring. The primary hypothesis being tested is that the Glasgow Outcome Score (GOS) 6 months after acute care discharge will be significantly better in those monitored with the continuous CPP display. Secondary endpoints are GOS at discharge and 3 months after discharge, Functional Independence Measure (FIM) score at discharge, and the Functional Status examination at 3 and 6 months. The percentage of CPP below set levels during hospital monitoring will be determined. No CPP thresholds have been established that adequately predict how well children who survive a brain injury will do. Thus we will describe the association between various CPP thresholds and children's outcome up to one year after their brain injury. The target number of children to be enrolled is 65. Studies suggest that the regularity or variability of physiologic measures, for example, heart rate, may give information about how well the system can respond to challenges. Changes in variability may be associated with disease. Describing physiologic variability may therefore be useful to identify critically ill individuals with brain injury who are less able to adapt to challenges and may be a greater risk for further brain injury and poorer outcome. Measures of the value that individuals place on the various health states are used to calculate quality adjusted life years and assess the cost-effectiveness of treatments. While measures have been developed to assess how individuals value different outcomes, information regarding the value placed on outcomes following brain injury is lacking. We will use these measures to carry out interviews of both brain injury survivors and those who have not had a brain injury to add to the knowledge in this area.