Should Standards/Guidelines/Practice Parameters Be Developed for Neuroanesthesiology or Other Subspecialties?

A standard is defined as a “level of quality or excellence,” while a guideline is defined as “official advice.”¹ A parameter is defined as “a fact or circumstance that restricts how something is done or what can be done.”¹ Guidelines have to date been developed by ASA for many aspects of anesthesia, including nothing-by-mouth status, conscious sedation, obstetric anesthesia and airway management. Although they are not labeled as standards, many of these guidelines incorporate aspects of anesthesia that have come to be accepted as standards of practice (i.e., CO₂ monitoring, pulse oximetry).

Neuroanesthesia has been recognized as a subspecialty by ASA since 1976.² The Society of Neurosurgical Anesthesia and Critical Care (SNACC) was founded in 1973 (it was originally named the Neurosurgical Anesthesia Society) and began publishing the Journal of Neurosurgical Anesthesia in 1989.² More than 30 academic institutions currently offer fellowships in neuroanesthesia, and most academic institutions, if not all, have a distinct division of neuroanesthesiology. Most likely every resident currently completing the third year of anesthesiology training has completed at least one rotation in neuroanesthesia and has probably been supervised by an anesthesiology attending with neuroanesthesia subspecialty training. Yet no official guidelines currently exist for the practice of neuroanesthesiology.

Should guidelines for care of the neurosurgical patient be developed? While most of these patients in academic centers are receiving care from subspecialty-trained anesthesiologists in the operating room as well as the intensive care unit, this may not be the case in smaller private practices and rural settings. Cases considered routine in large centers, such as aneurysm surgery and posterior fossa craniotomy, may occur much less frequently in smaller centers. The existence of guidelines might aid the anesthesiologist in such a setting where certain neurosurgical procedures are less frequent. For anesthesiologists who do not routinely practice neuroanesthesia, these guidelines could provide a template to follow when presented with a complicated neurosurgical patient.

By creating guidelines through SNACC, a consensus of practice from neuroanesthesiologists around the world could be produced. These guidelines could be adapted and updated as practice patterns, outcome data and clinical research evolve. A recent survey was conducted among the members of SNACC to assess current clinical practice for a variety of neurosurgical procedures.³ The survey reviewed 145 respondent neuroanesthesiologists — encompassing more than 55,000 surgical cases in both the United States and abroad — who answered more than 400 questions regarding their practice patterns. The data demonstrated relative uniformity in practice patterns. Among many clinical issues, for example, there was fair consensus of opinions regarding the medical management of cerebral vasospasm, utility of hyperosmolar solutions, the use of crystalloid, blood products and artificial colloid toward targeted hemodynamic goals and the selection of anesthetic agents. Such practice patterns endorsed and compiled by SNACC could be used to generate a set of guidelines. In addition publication of such educational material would serve to increase awareness of the society’s existence as well as interest in the subspecialty at a time when fewer graduating residents are choosing fellowship training and academic careers. More importantly if the number of fellowship-trained anesthesiologists continues to diminish, the number of neurosurgical patients receiving care from nonspecialty-trained physicians may increase, further increasing the usefulness of guidelines in the care of these patients.

In the area of neuroscience critical care, data have accumulated in support of subspecialty-trained intensivists when managing critically ill neurosurgical patients.⁴ Intuitively one could expect similar results in the operating theater regarding neuroanesthetic expertise. A paucity of clinical evidence-based medicine exists on neurological outcomes comparing different practice patterns or between general and subspecialty anesthesiologists. Guidelines could be created, though, based on neuroanesthesia principles as well as routine practice among neuroanesthesia-trained personnel to assist in management of the neurosurgical patient. These guidelines can be adjusted or adapted as evidence-based medicine evolves. By creating guidelines that focus on practice based on neurological physiology as well as emphasizing existing data and controversies, SNACC could provide direction as well as education to our anesthesiology colleagues.

Guidelines may, however, harbor several disadvantages. Many clinical care issues within the neuroanesthesiology discipline remain unresolved and are at the forefront of current research, such as the ability to provide anesthetic neuroprotection, identifying optimal hemodynamic/perfusion goals and the role of intraoperative hypothermia. Determining the impact of intraoperative monitoring on outcome is another example of ongoing investigation. Such monitoring is not uniformly available at all hospitals and illustrates the difficulty of proposing a guideline that may not be widely instituted. Further, creation of guidelines may, in fact, impede future research into these areas. Investigation would be stifled as practitioners are steered toward a practice pattern by well-intentioned but scientifically unsubstantiated management recommendations. Ramifications of practice standards may reach into the legal arena, further dissuading deviation from a guideline, and soon transform the “guide” into clinical dogma. Thus it may be premature to create guidelines until there are better data.

Certainly the debate continues as to whether guidelines should be created for our subspecialty of neuroanesthesia. Our society has currently reconciled to the fact that our patients may benefit from subspecialty anesthetic care. Such benefit, however, may be derived not from strict adherence to discreet procedures or goals but rather from the attention to neurophysiological detail and incorporation of that data into the comprehensive management plan that our expertise brings to the patient.

References:

1. Encarta® World English Dictionary [North American Edition] 2003.

2. Albin, MS. Celebrating Silver: The Genesis of a Neuroanesthesiology Society. J Neurosurg Anesthesiol. 1997; vol.9, no. 4: 296-307.

3. Moore L, Berkow L, et al. A Survey of SNACC Members’ Clinical Practice of Neuroanesthesia.J Neurosurg Anesthesiol.. 2002; Vol. 14, No 4: 350.

4. Mirski MA, Chang C, Cowan R, Positive Impact of a Neuroscience Intensive Care Unit on Neurosurgical Patient Outcomes and Cost of Care: Evidence-Based Support for Intensivist Directed Specialty ICU Model of Care, J Neurosurg Anesthesiol. 2001; 13:83-92.

Lauren C. Berkow, M.D., is Assistant Professor, Division of Neuroanesthesia, Johns Hopkins Medical Institutions, Baltimore, Maryland.

Marek A. Mirski, M.D., Ph.D., is Director, Neuroscience Critical care Unit, Chief, Division of Neuroanesthesiology and Associate Professor of Anesthesiology and Critical Care Medicine, Neurology and Neurosurgery, Johns Hopkins Medical Institutions, Baltimore, Maryland.