To develop a safe and standardized EVD (external ventricular drain) weaning initiation protocol for physicians working in an ICU.

The EVD weaning process has been used for decades, however there have not been unified criteria about when to initiate it. Historically, this decision has been deferred to neurosurgery. Over the past several years, we have developed a safe, reproducible, and standardized protocol for any physician working in an ICU. The greatest challenge was determining when this process should begin. Here, we present how to initiate this process in 5 simple steps.

The initiation process for gradual EVD weaning began when aneurysmal SAH and non-aneurysmal nontraumatic SAH patients met the following criteria: 1) the reason for EVD placement resolved or is resolving, 2) quantity of CSF output is <250mL over 24 hours, 3) quality of CSF must be nonbloody, 4) ICP must be within normal limits, and 5) the patient must be neurologically stable on physical exam. It was acceptable to wean when the patient had mild cerebral vasospasm, but not moderate to severe cerebral vasospasm. EVD weaning was performed by increasing drain height 5mmHg every 24 hours until reaching 20mmHg, at which point the EVD was clamped. If a head CT obtained 24 hours after clamping showed a stable ventricular system, the EVD was removed.

Aneurysmal SAH patients who underwent this EVD wean initiation criteria had lower rates of VPS/ETV placement (11%) compared to 21% nationally, as well as lower hospital length of stay (LOS) at 20.35 days compared to 21.5 days nationally.

Our criteria to initiate EVD weaning is a standardized approach that improves patient outcomes by reducing LOS and rates of costly and more invasive VPS/ETV procedures. By implementing similar criteria, other institutions can reach similar outcomes.