The diagnosis of brain death is a complex process. Strong knowledge of neurophysiology and an understanding of brain death etiology must be used to confidently determine brain death. The key findings in brain death are unresponsiveness, and absence of brainstem reflexes in the setting of a devastating neurological injury. These findings are coupled with a series of confirmatory tests, and the diagnosis of brain death is established based on consensus recommendations. The drive to breathe in the setting of an intense ventilatory stimulus (ie, respiratory acidosis) is a critical marker of brainstem function. As a consequence, apnea testing is an important component of brain death assessment. This procedure requires close monitoring of a patient as all ventilator support is temporarily removed and PaCO 2 levels are allowed to rise. A "positive" test is defined by a total absence of respiratory efforts under these conditions. While apnea testing is not new, it still lacks consensus standardization regarding the actual procedure, monitored parameters, and evidencebased safety measures that may be used to prevent complications. The purpose of this report is to provide an overview of apnea testing and discuss issues related to the administration and safety of the procedure.

Background Treatment of brain injury is often focused on minimizing intracranial pressure, which, when elevated, can lead to secondary brain injury. Chest percussion is a common practice used to treat and prevent pneumonia. Conflicting and limited anecdotal evidence indicates that physical stimulation increases intracranial pressure and should be avoided in patients at risk of intracranial hypertension.Objectives To explore the safety of performing chest percussion for patients at high risk for intracranial hypertension.Methods A total of 28 patients with at least 1 documented episode of intracranial hypertension who were having intracranial pressure monitored were studied in a prospective randomized control trial. Patients were randomly assigned to either the control group (no chest percussion) or the intervention group (10 minutes of chest percussion at noon). Intracranial pressure was recorded once a minute before, during, and after the intervention.Results Mean intracranial pressures for the control group before, during, and after the study period (14.4, 15.0, and 15.9 mm Hg, respectively) did not differ significantly from pressures in the intervention group (13.6, 13.7, and 14.2 mm Hg, respectively).Conclusions Mechanical chest percussion may be a safe intervention for nurses to use on neurologically injured patients who are at risk for intracranial hypertension.

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