Response to ASNM intraoperative SSEP position statement.

This correspondence is in response to Dr. David Allison's comments to the Editor, regarding the American Society of Neurophysiological Monitoring's (ASNM) updated intraoperative somatosensory evoked potential (SEP) monitoring position statement.

Intraoperative somatosensory evoked potential (SEP) monitoring: an updated position statement by the American Society of Neurophysiological Monitoring.

Somatosensory evoked potentials (SEPs) are used to assess the functional status of somatosensory pathways during surgical procedures and can help protect patients' neurological integrity intraoperatively. This is a position statement on intraoperative SEP monitoring from the American Society of Neurophysiological Monitoring (ASNM) and updates prior ASNM position statements on SEPs from the years 2005 and 2010. This position statement is endorsed by ASNM and serves as an educational service to the neurophysiological community on the recommended use of SEPs as a neurophysiological monitoring tool.

Multimodal Analgesia and Intraoperative Neuromonitoring.

Intraoperative neuromonitoring has been a valuable tool for ensuring the functional integrity of vital neural structures by providing real-time feedback to the operative team during procedures where neurological structures are at risk. Commonly used intravenous and inhaled anesthetic drugs are known to affect waveform parameters measured with various intraoperative neuromonitoring modalities. While the concept of opioid-sparing multimodal analgesia has gained popularity in recent years, the impact of such a strategy on intraoperative neuromonitoring remains poorly characterized, in contrast to the more well-established concepts and literature regarding the effects of other hypnotic agents on neuromonitoring quality.

Cautionary findings for motor evoked potential monitoring in intracranial aneurysm surgery after a single administration of rocuronium to facilitate tracheal intubation.

Administration of rocuronium to facilitate intubation has traditionally been regarded as acceptable for intraoperative motor evoked potential (MEP) monitoring because of sufficiently rapid spontaneous neuromuscular blockade recovery. We hypothesized that residual neuromuscular blockade, in an amount that could hinder optimal neuromonitoring in patients undergoing intracranial aneurysm clipping, was still present at dural opening. We sought to identify how often this was occurring and to identify factors which may contribute to prolonged blockade.

Practice guidelines for the supervising professional: intraoperative neurophysiological monitoring.

The American Society of Neurophysiological Monitoring (ASNM) was founded in 1989 as the American Society of Evoked Potential Monitoring. From the beginning, the Society has been made up of physicians, doctoral degree holders, Technologists, and all those interested in furthering the profession. The Society changed its name to the ASNM and held its first Annual Meeting in 1990.

A Case Report of Onyx Pulmonary Arterial Embolism Contributing to Hypoxemia During Awake Craniotomy for Arteriovenous Malformation Resection.

A healthy 26-year-old man with cerebral arteriovenous malformation underwent staged endovascular embolization with Onyx followed by awake craniotomy for resection. The perioperative course was complicated by tachycardia and severe intraoperative hypoxemia requiring significant oxygen supplementation. Postoperative chest computed tomography (CT) revealed hyperattenuating Onyx embolization material within the pulmonary vasculature, and an electrocardiogram indicated possible right heart strain, supporting clinically significant embolism.

Nicardipine is superior to esmolol for the management of postcraniotomy emergence hypertension: a randomized open-label study.

Background: Emergence hypertension after craniotomy is a well-documented phenomenon for which natural history is poorly understood. Most clinicians attribute this phenomenon to an acute and transient increase in catecholamine release, but other mechanisms such as neurogenic hypertension or activation of the renin-angiotensin-aldosterone system have also been proposed. In this open-label study, we compared the monotherapeutic antihypertensive efficacy of the 2 most titratable drugs used to treat postcraniotomy emergence hypertension: nicardipine and esmolol.

West Nile virus infection and postoperative neurological symptoms: a case report and review of the literature.

The incidence of West Nile virus, which may cause a range of clinical presentations including subclinical infections, mild febrile illness, meningitis, or encephalitis, has increased over recent years. Rare complications, including optic neuritis, also have been reported. A patient who presented with preoperative asymptomatic West Nile virus developed fever, altered mental status and temporary vision loss after elective multilevel spine fusion surgery.

The implementation and efficacy of the Northwestern High Risk Spine Protocol.

Objective: The aims of this study were to determine the efficacy and feasibility of implementation of the intraoperative component of a high risk spine (HRS) protocol for improving perioperative patient safety in complex spine fusion surgery.

Methods: In this paired availability study, the total number of red blood cell units transfused was used as a surrogate marker for our management protocol efficacy, and the number of protocol violations was used as a surrogate marker for protocol compliance.

Results: The 548 patients (284 traditional vs.

Predicting major adverse cardiac events in spine fusion patients: is the revised cardiac risk index sufficient?

Study Design: Observational cohort study.

Objective: To determine the accuracy of the Revised Cardiac Risk Index (RCRI) in predicting major adverse cardiac events in patients undergoing spine fusion surgery of 3 levels or more.

Summary Of Background Data: Preoperative cardiac testing is extensively guided by the RCRI, which was developed and validated in thoracic, abdominal, and orthopedic surgical patients.

Development and validation of a generalizable model for predicting major transfusion during spine fusion surgery.

Background: Surgery for posterior spine instrumentation often requires major transfusion. The aim of this study was to develop and test the validity of a model for predicting intraoperative major transfusion (>4 U total red blood cells), based on preoperative patient and surgical variables, that was applicable to adult patients undergoing cervical, thoracic, and/or lumbar spine deformity surgery with and without osteotomies.

Materials And Methods: The perioperative data from 548 patients who underwent ≥ 3 levels of posterior spinal fusion with instrumentation between January 1, 2003 and May 30, 2009, were retrospectively collected to create a model for predicting major blood transfusion.

Adenosine-induced flow arrest to facilitate intracranial aneurysm clip ligation does not worsen neurologic outcome.

Background: When temporary arterial occlusion of the parent artery is difficult for anatomical reasons, or when inadvertent aneurysmal rupture occurs during surgical dissection, adenosine administration can be used to produce flow arrest and brief, profound systemic hypotension that can facilitate intracranial aneurysm clip ligation. There is a concern, however, that the flow arrest and profound hypotension produced by adenosine, although brief, may cause cerebral ischemia and therefore worsen neurologic outcome compared with other techniques to facilitate aneurysm clip ligation. Therefore, we performed a retrospective, case-control study to determine whether adenosine-induced flow arrest had negative effects on the neurologic outcome of our patients.

The effect of furosemide on intravascular volume status and electrolytes in patients receiving mannitol: an intraoperative safety analysis.

Background: Mannitol is often used during intracranial surgery to improve surgical exposure. Furosemide is often added to mannitol to augment this effect. The concern exists, however, that the augmented diuresis caused by the addition of furosemide to mannitol may cause hypovolemia and hypoperfusion, hypokalemia, and hyponatremia.

The incidence of unacceptable movement with motor evoked potentials during craniotomy for aneurysm clipping.

Objective: To review the experience at a single institution with motor evoked potential (MEP) monitoring during intracranial aneurysm surgery to determine the incidence of unacceptable movement.

Methods: Neurophysiology event logs and anesthetic records from 220 craniotomies for aneurysm clipping were reviewed for unacceptable patient movement or reason for cessation of MEPs. Muscle relaxants were not given after intubation.

Anesthesia implications of waterpipe use.

The waterpipe is an ancient Middle Eastern tobacco delivery system, which is also known as hookah, shisha, or narghile, and it is gaining widespread use. Waterpipes are often perceived as less dangerous than cigarettes. The amount of smoke inhaled in a waterpipe session may equal that produced by more than 100 cigarettes with high nicotine, carbon monoxide, and carcinogen intake.

Adenosine-induced flow arrest to facilitate intracranial aneurysm clip ligation: dose-response data and safety profile.

Background: Adenosine-induced transient flow arrest has been used to facilitate clip ligation of intracranial aneurysms. However, the starting dose that is most likely to produce an adequate duration of profound hypotension remains unclear. We reviewed our experience to determine the dose-response relationship and apparent perioperative safety profile of adenosine in intracranial aneurysm patients.

Trigeminocardiac reflex in the Postanesthesia care unit.

Bradycardia caused by the oculocardiac reflex is an anticipated occurrence during certain surgeries. The afferent pathway involves the trigeminal nerve's ophthalmic division. Reflex bradycardia from the trigeminocardiac reflex, via stimulation of maxillary or mandibular divisions of cranial nerve V, although less well known, has also been reported intraoperatively.