A venous air embolism (VAE) is a potentially life-threatening event caused by air in the vascular system. The entrainment of air from an operative site into the venous vasculature produces a wide array of systemic effects. This chapter presents a case study of a 37-year-old female with a right-sided acoustic neuroma presenting for a suboccipital approach to tumor resection. VAE was historically most often associated with craniotomies performed in the sitting position. Clinical presentation depends on the severity of the air embolus. There are several monitors that are capable of detecting venous air emboli. The most sensitive is transesophageal echocardiography (TEE). The presence of TEE also enables direct visualization of air aspiration through a central catheter if a VAE should occur. Monitors for high-risk cases should be chosen depending on the expertise of the anesthesiologist, the surgery being performed, and the position of the patient.

Intracranial pressure (ICP) is of paramount importance because the cranial vault is nondistensible and within it is contained three noncompressible substances: brain, blood, and cerebrospinal fluid (CSF). This chapter presents a case study of a 75-year-old male who presented for emergent subdural hematoma evacuation. The immediate anesthetic goal was to minimize the rise in ICP while at the same time maintaining adequate cerebral perfusion pressure until the neurosurgeons could provide definitive treatment. Definitive correction of intracranial hypertension was achieved with hematoma evacuation. Intracranial hematomas, blood-filled space-occupying lesions, are classified by their location relative to the meningeal layers. Numerous therapeutic maneuvers exist for lowering ICP, each with the common mechanism of decreasing the volume of one or more intracranial components. increased ICP can be a life-threatening condition, the definitive treatment of which is often in the hands of the neurosurgeon.