Neurosurgical Anesthesia

As I finish my month on anesthesia for brain surgeries, I reflect on how neurosurgical anesthesia differs from what we do for other procedures. Here, I get detailed neurologic exams of the patient pre-operatively so I know what to expect post-operatively. This is in contrast to an acute abdomen or an ankle fracture; I don't necessarily check for rebound tenderness or palpate a joint as part of my pre-anesthetic workup. But anesthesia does not affect those organ systems as much as it affects cognition, information processing, and mental status. As a result, we have to know a patient's baseline neuro exam and select an anesthetic plan and pain medications to minimize interference after the surgery.

Although modulating blood pressure is an important aspect of all anesthetics, it is critical in neurosurgery. Too much pressure and the surgical site bleeds or aneurysms burst. Too little and the patient may stroke. Thus, modulating pressure, especially at the wake-up, requires attentive, careful, and deliberate titrations of highly vasoactive substances.

Similarly, anesthesiologists are able to control the pressure inside the brain. Because the skull is a fixed cavity, increased intracranial pressure - from swelling, too much cerebral spinal fluid, dilated blood vessels - can be lethal. With pharmacologic, respiratory, and mechanical interventions, we can prevent brainstem herniation and give surgeons better operative fields.

Despite these particularities about neurosurgery, the anesthesia is not so different from that for other cases. At the conclusion of this block, I will have rotated through pretty much all the various surgical services and seen most operations in a multispecialty hospital. Hopefully, this has prepared me well for my final year of residency.