An Approach to Determining Intracranial Pressure Variability Capable of Predicting Decreased Intracranial Adaptive Capacity in Patients With Traumatic Brain Injury

Nurses caring for traumatic brain injury (TBI) patients with intracranial hypertension (ICH) recognize that patients whose intracranial adaptive capacity is reduced are susceptible to periods of disproportionate increase in intracranial pressure (DIICP) in response to a variety of stimuli. It is possible that DIICP signals potential secondary brain damage due to sustained or intermittent ICH. However, there are few clinically accessible intracranial pressure (ICP) measurement parameters that allow nurses and other critical care clinicians to identify patients at risk of DIICP. The purpose of this study was to investigate whether there are specific minute-to-minute trends in ICP variability during the first 48 hr of monitoring that might accurately predict DIICP in patients with severe TBI. A total of 38 patients with severe TBI were sampled from the data set of a randomized controlled trial testing bedside monitoring displays and cerebral perfusion pressure management in individuals with TBI or sub-arachnoid hemorrhage. The investigators retrospectively examined the rates of change (slope) in mean, standard deviation, and variance of ICP on a 1-min basis for 30 consecutive min prior to a specified DIICP event. There was a significantly increasing linear and quadratic slope in mean ICP prior to the development of DIICP, compared with the comparison data set (p < .05). It is feasible to display moving averages in modern bedside monitoring. Such an arrangement may be useful to provide visual displays that provide immediate clinically relevant information regarding the patients with decreased adaptive capacity and therefore increased risk of DIICP.