From the Research
In an unsecured aneurysm with subarachnoid hemorrhage, the external ventricular drain (EVD) is typically set at 18 cm H2O, as this setting is commonly used in clinical practice, according to a survey of institutional practices 1. This setting is crucial to prevent rapid reduction in intracranial pressure that could trigger rebleeding from the unsecured aneurysm. After the aneurysm is secured through surgical clipping or endovascular coiling, the EVD setting can be gradually lowered to facilitate CSF drainage and help clear blood products from the ventricular system. The EVD should be positioned at the level of the foramen of Monro (approximately at the external auditory meatus) for accurate pressure readings. Regular monitoring of intracranial pressure, neurological status, and drainage volume is essential, with adjustments made based on the patient's clinical condition and response to treatment.
Some key considerations in EVD management include:
- The use of continuous versus intermittent drainage, with some evidence suggesting that intermittent drainage may be associated with fewer complications and shorter length of stay 2
- The importance of monitoring for signs of EVD-associated infection and taking steps to minimize this risk
- The need for individualized management approaches, taking into account the patient's specific clinical condition and response to treatment
It's worth noting that the optimal management of EVDs in patients with aneurysmal subarachnoid hemorrhage is not yet fully established, and more research is needed to determine the best practices in this area 1, 2. However, based on the available evidence, setting the EVD at 18 cm H2O in unsecured aneurysms appears to be a reasonable approach, with the goal of balancing the need to manage increased intracranial pressure with the risk of rebleeding. Further studies, such as multicenter prospective trials, are necessary to confirm the efficacy and safety of this approach 1, 2.