The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts


Stacey N. Bennett1, N. T. Bennett1, Michael L. James1, Carmelo Graffagnino1

Background: Patients with acute brain injury are often at risk for the development of ARDS. Treating ARDS has been a common problem for healthcare providers managing patients in neurocritical care units. Initial data in other adult subgroups shows favorable outcomes with the use of high frequency oscillatory ventilation (HFOV) on ARDS. However, little is known about how HFOV affects intracranial pressures (ICP) in those with acute brain injury. Here we report five cases of HFOV used in patients with acute brain injury and its effect on ICP, CPP, PaO2, and PaCO2.

Methods: Patients who received HFOV were identified through the Duke University Medical Center Respiratory Database. A total of seven patients received HFOV in the Neurocritical Care Unit (NCCU) over eighteen months. Five of these patients had acute brain injury as their primary diagnosis and ARDS as a secondary diagnosis. Each chart was retrospectively reviewed to evaluate changes in ICP, cerebral perfusion pressure (CPP), blood pressure (BP), carbon dioxide (PaCO2) and oxygenation (PaO2). Values for ICP, CPP, BP, PaCO2, and PaO2 were measured while the patients received conventional ventilation and HFOV. When available values for PbTO2 were also recorded to determine cerebral oxygenation. The values obtained while on conventional mechanical ventilation (CMV) were compared with values recorded on HFOV. Sedation and ICP management were the same for all patients. Mannitol and 23% saline were used per the NCCU protocol to maintain ICP ? 20mmHg. Sedation was begun with Propofol and Fentanyl infusions. Versed and Cisatricurium infusions were instituted in addition to Fentanyl during CMV as needed for further ventilator synchrony and prior to any transition to HFOV.

Results: All five patients survived their acute brain injury and were able to be transitioned from CMV to HFOV and then back to CMV. None of the patients exhibited clinically significant changes in ICP, CPP, or BP while receiving HVOF as compared to conventional ventilation. Some patients did experience an increase in PaCO2 levels but these changes were transient and did not cause unmanageable increases in ICP. All patients experienced an improvement in PaO2.

Conclusion: In our small series, HFOV possessed no more risk of increasing ICP than CMV. Therefore, HFOV may be considered by clinicians for the management of patients with acute brain injury and concomitant ARDS.