Mitchell has proposed a series of factors that may aid in the identification of individual patients with intracranial hypertension at risk for decreased intracranial adaptive capacity.4 The etiology of decreased intracranial adaptive capacity is failure of normal intracranial compensatory mechanisms. The defining characteristic of this nursing diagnosis is repeated disproportionate increase in intracranial pressure (ICP) that can occur in response to a variety of noxious and nonnoxious stimuli. The purpose of this study was to determine predictive validity of two risk factors (wide amplitude of ICP tracing and increased level of ICP at rest) for the phenomenon of decreased intracranial adaptive capacity. Data were derived from secondary analysis of 30 recordings from a sample of eight children who had ICP monitoring as part of their medical treatment. Results indicated that wide amplitude of ICP tracing or wide amplitude plus increased level of ICP at rest (specificity and positive predictive value were each 100%) with suctioning and turning was more likely to be associated with a disproportionate increase in ICP than when an increased level of ICP at rest alone was the only risk factor (specificity = 25% and positive predictive value = 67% with suctioning and specificity and positive predictive value each = 40% with turning). It was also concluded that despite high positive predictive values, the combination of risk factors was sufficient but not solely necessary for a disproportionate increase in ICP (false negative predictive value for wide amplitude was 65% with suctioning and false negative predictive value for increased level of ICP was 83% with suctioning and 43% with turning). Therefore, it is recommended that nurses continue to provide measures to reduce adaptive demand or increase adaptive capacity in patients with intracranial hypertension whether or not the risk factors, wide amplitude of ICP tracing and increased level of ICP at rest, are present.
Questions or comments about this article may be addressed to Mary E. Rauch at: Harborview Medical Center, 325 9th Avenue, Division of Neurology, ZA-95, Seattle, Washington 98104. She is a research nurse for the division of neurology and a clinical nurse specialist in the ambulatory neurology clinic.
Pamela H. Mitchell is a professor in the department of physiological nursing at the University of Washington, Seattle.
Martha L. Tyler is an assistant professor in the department of physiological nursing and an adjunct assistant professor in the division of pulmonary and critical care medicine at the University of Washington, Seattle.
© 1990 American Association of Neuroscience Nurses