Effects of Head-of-Bed on Intracranial Pressure

Response of Intracranial Pressure Based on Head-of-Bed Positioning in Aneurysmal Subarachnoid Hemorrhage

The purpose of this study is to evaluate how pressure inside the skull responds to position changes in patients with brain bleeds.

The optimal positioning of the head-of-bed (HOB) has remained controversial in the neurosurgical field. Very limited data exists outlining the effects of HOB positioning in subarachnoid hemorrhage (SAH) patients. One study by Schulz-Stubner and Thiex assess the effects of HOB positioning in SAH and traumatic brain injury (TBI) patients. While this study offers some valuable insight into the changes in cerebral hemodynamics seen when the HOB changes, it congregates data from two very different pathologies. This could potentially misrepresent the true effects patients experience. A study by Kung et al. assesses cerebral blood flow dynamics and HOB changes in the setting of SAH but does not evaluate the effects on intracranial pressure (ICP) (Kung, et al., 2013). There appear to be no studies which evaluate the effect of HOB positioning on ICP in patients with SAH. No current data exists to determine if dependent leg positioning would help to further lower ICP. Theoretically, placing a patient's legs in a dependent position would lead to increased venous pooling of blood in the legs which might translate to lower ICP.

Inclusion Criteria:

• Patients with subarachnoid hemorrhage confirmed by CT scan, MRI, or cerebral angiogram
• Age ≥ 18 years old
• Patients with intracranial pressure monitoring device
• Patients with continuous arterial blood pressure monitoring
• The subject or legally authorized representative must be available and able to consent

Exclusion Criteria:

• Intubated patients who are prone
• Patients with left ventricular ejection fraction <20% as evidenced by echocardiogram previously documented at any time in the electronic medical record
• Patients with a diagnosis of pulmonary hypertension
• Patients with a diagnosis of cirrhosis and/or evidence of liver failure. Evidence of liver failure will be assessed by the presence of ascites, edema, abnormal lab values including low albumin, elevated PTT, elevated PT, elevated INR, or elevated bilirubin without another etiology, or MELD score >8.
• Patients who are clinically unstable defined as those who are unable to lie flat for 30 minutes for any reason, patients on more than one continuous IV medications to increase blood pressure, or patients who are actively undergoing resuscitation.