Alaina Martini, a flight nurse at Allegheny Life Flight, shares her expertise in transporting patients with external ventricular drains (EVDs). She explains the indications for EVD insertion, such as aneurysmal subarachnoid hemorrhage and obstructive hydrocephalus. Alaina discusses the importance of assessing the color and texture of the cerebrospinal fluid (CSF) to detect changes and potential rebleeding. She also explains the process of inserting the EVD and how it is guided by CT scans to avoid damaging important brain tissue. Alaina emphasizes the need to know if the aneurysm is secure before adjusting the EVD drain level, as opening it too low can increase the risk of rebleeding. She also discusses the use of hypertonic saline and osmotic therapy to manage increased intracranial pressure. Tyler and Alaina discuss various aspects of managing patients with external ventricular drains (EVDs) during transport in this conversation. They cover topics such as the clamping of EVDs, positioning the patient's head, troubleshooting common issues, and securing the EVD during transport. Alaina provides insights and recommendations based on her experience as a neurocritical care nurse.
EVD Transport Checklist
When was the EVD placed, and why?
Aneurysmal SAH
Arteriovenous malformation (AVM)
ICH with ventricular extension
Low-pressure hydrocephalus
Meningitis or other infectious process)
What was the opening pressure?
Predictor of clinical outcome
Current EVD orders?
Is it to be kept clamped and utilized for ICP measurement only? (Most commonly seen with low-pressure hydrocephalus)
Is it open to drain?
If so, what is the ordered level? (ie. 5cmH20, 10cmH20)
REMEMBER - be cautious opening below 10cmH20 if placed for aneurysmal SAH or AVM AND aneurysm/AVM has not yet been secured (clipped or coiled) due to high risk of rebleeding.
Is the ICP waveform appropriate?
Should have three separate peaks (P1, P2, P3) all descending in height
Should correlate with HR and arterial line waveforms
What is the patient's average ICP?
Expect a range
Clamp EVD for a least 30 seconds before determining an ICP reading
Does the patient tolerate clamping?
If so, how long was the clamp trial? (ie. clamped for patient position change only or clamped for an extended period for a CT or MRI)
What is the average drainage of CSF per hour?
Expect a range
What color is the drainage?
Color is generally a cherry red to serosanguineous following EVD placement
The longer the EVD is in, drainage will change over to a pale yellow color
If drainage suddenly changes to frank red blood, the patient is likely rebleeding. (Trust me, you'll recognize the color change when you see it).
Takeaways
External ventricular drains (EVDs) are inserted for conditions such as aneurysmal subarachnoid hemorrhage and obstructive hydrocephalus.
Assessing the color and texture of the cerebrospinal fluid (CSF) is important to detect changes and potential rebleeding.
EVD insertion is guided by CT scans to avoid damaging important brain tissue.
The level at which the EVD drain is set depends on whether the aneurysm is secure.
Hypertonic saline and osmotic therapy may be used to manage increased intracranial pressure. Clamping an EVD during transport is generally well-tolerated by most patients, but some patients may not tolerate it well.
The patient's head should be kept in a neutral position or elevated at 30 degrees during transport to promote venous return and divert cerebrospinal fluid away from the cerebral part.
Securing the EVD during transport is important to prevent it from becoming a projectile in case of turbulence or a hard landing.
Troubleshooting common issues with EVDs during transport includes checking for obstructions or occlusions in the drainage tubing and addressing them accordingly.
Monitoring the patient's level of consciousness and the waveform of the ICP (intracranial pressure) can help identify potential issues with the EVD.
In-flight noise and stimulation should be minimized as much as possible to prevent increases in ICP.
Creative solutions may be needed to secure the EVD in helicopters or ground ambulances without dedicated IV poles.
Flushing the EVD should be done cautiously, and sterile water is preferred over normal saline to avoid potential irritation to the brain tissue.
Clamping Procedure
Hypertonic Therapy?
What is the goal? Drain CSF or absorb edema?
References
Chaikittisilpa, N., Lele, A. V., Lyons, V. H., Nair, B. G., Newman, S. F., Blissitt, P. A., & Vavilala, M. S. (2017). Risks of Routinely Clamping External Ventricular Drains for Intrahospital Transport in Neurocritically Ill Cerebrovascular Patients. Neurocritical care, 26(2), 196–204. https://doi.org/10.1007/s12028-016-0308-0
Muralidharan R. (2015). External ventricular drains: Management and complications. Surgical neurology international, 6(Suppl 6), S271–S274. https://doi.org/10.4103/2152-7806.157620
Thamjamrassri, T., Yuwapattanawong, K., Chanthima, P., Vavilala, M. S., Lele, A. V., & EVDPoP Study Collaborators (2022). A Narrative Review of the Published Literature, Hospital Practices, and Policies Related to External Ventricular Drains in the United States: The External Ventricular Drain Publications, Practices, and Policies (EVDPoP) Study. Journal of neurosurgical anesthesiology, 34(1), 21–28. https://doi.org/10.1097/ANA.0000000000000694
