The Neurosurgical Intensive Care Unit and the Unique Role of the Neurosurgeon

History of the Neuro-Icu and Harvey Cushing’s Contributions

One of Harvey Cushing’s seminal works, “Concerning a definite regulatory mechanism of the vaso-motor center which controls blood pressure during cerebral compression,” provided a foundational basis for many of the principles deployed in modern neurocritical care. The piece, written in 1901 as part of the Bulletin of the Johns Hopkins Hospital , investigated the relationship of saline-induced increases in intracranial pressure (ICP) with corresponding increases in arterial blood pressure, as well as partial cessation of respiration. The landmark study helped elucidate vagal and spinal reflexes associated with elevated ICPs, ultimately leading to the famous discovery of the “Cushing response.” Prevention of the Cushing response and elevated ICPs to help avoid secondary injury remains a paramount function of neurocritical care to this day. Another of Cushing’s many landmark contributions to the field of neurocritical care pertains to his observations during World War I. After recognizing that nearly 60% of deaths from penetrating head trauma were in fact due to cerebral infections, Cushing was able to lower head trauma mortality from 54% to 29% via rapid débridement by the war’s end. With this development, one of Cushing’s residents, Hugh Cairns, brought about mobile head injury units staffed by a neurosurgeon, neurologist, and anesthesiologist. Many consider these mobile units the first dedicated neuro-ICUs.

Evaluation of the Neuro-Icu Patient

Without question, one of the most challenging tasks for physicians in the neuro-ICU is obtaining proper serial assessments. From patients requiring trephination to modern neuro-ICU levels of care with invasive monitoring and imaging, care of the neuro-ICU patient begins with a proper assessment. The unfortunate reality is that many neuro-ICU patients have poor mental status, have sustained brain injuries, or are intubated, which poses an even greater challenge for clinicians in obtaining histories and eliciting significant neurological changes. The expertise and clinical evaluation of a neurosurgeon is particularly valuable in neurocritical care units led by physicians from different medical or surgical backgrounds taking care of neurosurgical patients. The neurosurgeon is needed to recognize when changes in patients’ neurological status would benefit from prompt interventions.

Neurosurgical evaluation must begin early, at the time of admission of a patient to the neuro-ICU. Even though most neuro-ICU patients have been initially assessed by emergency department, medical-surgical, or referring hospital staff prior to arriving in the neuro-ICU, the evaluation in the neuro-ICU should begin with the reassessment and reevaluation of each patient admitted. This starts with a careful systems-based practice for all patient transfers, with proper communication and interpersonal skills between all teams regarding the patient’s neurological and systemic disorders, as well as all initial interventions that have been performed outside the neuro-ICU. The tight coordination among care teams should start prior to transfer and continue throughout the patient’s neuro-ICU stay. This is particularly important for patients with multiple medical issues requiring various medical consulting and ancillary services, including respiratory therapy, nutrition, physical therapy, and nursing teams.

Similar to the primary survey, all assessments of injury should begin with airway, breathing, and circulation (ABCs). Ensuring a secure airway, adequate oxygenation and ventilation, and hemodynamic stability is the foundation to appropriate cerebral and spinal perfusion. Particularly in patients with TBI, hypoxia or hypotension must be quickly managed and prevented to help avoid secondary injury. In all critically ill patients, and especially neuro-ICU patients, a careful history taking is challenging in those with an extensive medical history or in those with diminished mental status who are unable to relay any reliable history or medical information. Information must carefully be gathered from family members, bystanders, and first responders. After a careful review of the patient’s history and physical examination, neurosurgeons should review all imaging and pertinent laboratory results. In organizing this information, neurosurgeons must be able to quickly localize pathology within the neuraxis where a patient’s neurological deficit may arise. For all patients in the neuro-ICU, a full review of imaging studies is needed to determine the extent of neurological injury as well as any systemic injuries on plain films; CT scans of the brain, spine, chest, abdomen, or pelvis; or MR images. Evaluation of patients in the neuro-ICU must also include a comprehensive assessment of pulmonary, cardiac, infectious, and hematologic illnesses or injuries and their complications. Establishing a systems-based approach will help to ensure that details and necessary contextual information are maintained when evaluating these complex patients. This approach is necessary to develop an understanding of how these systemic illnesses and complications may affect the neuro-ICU patient’s neurological disorder. Complete clinical evaluation is paramount in the treatment of neuro-ICU patients in all systems models of neuro-ICU care, and especially when such care is coordinated and comanaged by intensivists with backgrounds other than neurosurgery.