Management of brain tumors presenting in pregnancy: a case series and systematic review.

Patients who present with brain tumors during pregnancy require unique imaging and neurosurgical, obstetrical, and anesthetic considerations. Here, we review the literature and discuss the management of patients who present with brain tumors during pregnancy. Between 2009 and 2019, 9 patients were diagnosed at our institution with brain tumors during pregnancy. Clinical information was extracted from the electronic medical records. The median age at presentation was 29 years (range, 25-38 years). The most common symptoms at presentation included headache (n=5), visual changes (n=4), hemiparesis (n=3), and seizures (n=3). The median gestational age at presentation was 20.5 weeks (range, 11-37 weeks). Of note, 8 patients (89%) delivered healthy newborns, and 1 patient terminated her pregnancy. In addition, 5 patients (56%) required neurosurgical procedures during pregnancy (gestational ages, 14-37 weeks) because of disease progression (n=2) or neurologic instability (n=3). There was 1 episode of postneurosurgery morbidity (pulmonary embolism [PE]) and no surgical maternal mortality. The median length of follow-up was 15 months (range, 6-45 months). In cases demonstrating unstable or progressive neurosurgical status past the point of fetal viability, neurosurgical intervention should be considered. The physiological and pharmacodynamic changes of pregnancy substantially affect anesthetic management. Pregnancy termination should be discussed and offered to the patient when aggressive disease necessitates immediate treatment and the fetal gestational age remains previable, although neurologically stable patients may be able to continue the pregnancy to term. Ultimately, pregnant patients with brain tumors require an individualized approach to their care under the guidance of a multidisciplinary team.

Intraoperative Transcranial Motor-evoked Potential Stimulation Does Not Seem to Cause Seizures.

BACKGROUND: Intraoperative neurophysiological monitoring is of critical importance in evaluating the functional integrity of the central nervous system during surgery of the central or peripheral nervous system. In a large recent study, transcranial motor-evoked potentials (TcMEPs) were found to be associated with a 0.7% risk of inducing a seizure as diagnosed by clinical observation and electromyography in patients having general anesthesia with intravenous anesthetics. The gold standard for seizure diagnosis, however, is electroencephalography (EEG). The aim of this single-institution retrospective study is to ascertain the risk of intraoperative seizures detected using EEG during surgeries in adult patients undergoing intraoperative monitoring with TcMEPs. METHODS: The authors retrospectively reviewed the intraoperative EEG records of 1175 patients anesthetized with a variety of anesthetic agents, including volatile and intravenous anesthetics, to ascertain the rate of EEG-diagnosed seizures attributable to TcMEPs. RESULT: Our analysis did not reveal a single seizure event attributable to TcMEPs in 1175 patients. CONCLUSION: The intraoperative use of TcMEPs does not seem to cause seizures.

Plasma nitrite as an indicator of cerebral ischemia during extracranial/intracranial bypass surgery in moyamoya patients.

BACKGROUND AND PURPOSE: Nitric oxide (NO) plays a key role in ischemia and shows potential as a biomarker for ischemia. We measured mixed venous nitrite (NO2-) as a proxy for NO, during controlled cerebral ischemia in patients with moyamoya disease (MMD) during direct extracranial/intracranial (EC/IC) bypass surgery with temporary occlusion of the M4 branch of the middle cerebral artery (MCA) to permit anastomosis with the superficial temporal artery (STA). This small, focal ischemic event is not reliably detected using cerebral oximetry, somatosensory evoked potentials (SSEPs) or electroencephalography (EEG). METHODS: We enrolled nine adult MMD patients (n=8 female, n=1 male) undergoing direct EC/IC bypass surgery. Nitrite was measured at least one hour prior to MCA occlusion, and before, during and after anastomosis. Cortical function was monitored using either multi-lead EEG and SSEPs, or frontal EEG activity. RESULTS: Mixed venous NO2- was significantly elevated (p<0.05) within 12 min following arterial occlusion vs. baseline. An M4 branch of the MCA was cross clamped for a median duration of 18 (IQR = 5) minutes during anastomosis. One patient with elevated NO2- showed a transient neurologic deficit that resolved 3 days post-operatively. CONCLUSIONS: Mixed venous NO2- was significantly elevated shortly following cerebral artery occlusion vs. baseline in a majority of the study subjects, suggesting that NO2- is a potential biomarker for ischemia. Since all patients received identical burst suppression anesthesia and vasopressors, the fact that NO2- was not elevated during cross-clamp in all patients supports the conclusion that the NO2- elevation is likely due to ischemia.

Paradoxical Critical Hyperkalemia After Acetazolamide for Cerebrovascular Reactivity Study: A Case Report.

We present the case of a 42-year-old man with moyamoya disease presenting for cerebral revascularization surgery who developed critical hyperkalemia following a single intravenous (iv) dose of 1000 mg of acetazolamide 1 day preoperatively for a cerebrovascular reactivity study. His potassium increased from 5.1 to 6.7 mmol/L. Prompt treatment of this abnormality allowed this patient to undergo surgery the next day uneventfully. A paradoxical, critical increase in potassium can result from a single 1000-mg iv dose of acetazolamide.

Effect of Head Rotation on Jugular Vein Patency Under General Anesthesia.

Head rotation causes compression and occlusion of the ipsilateral internal jugular (IJ) vein. This can result in raised intracranial pressure and increased bleeding if the patient is having or has recently had surgery. The amount of head rotation in adults resulting in occlusion of the ipsilateral IJ vein is unknown however. We measured the amount of head turn that produced occlusion of the ipsilateral IJ vein in 25 patients having surgery under general anesthesia. On average, 80% of IJ veins occlude at a mean of 55.6° on the left and 53.3° on the right.

Acetaminophen Does Not Reduce Postoperative Opiate Consumption in Patients Undergoing Craniotomy for Cerebral Revascularization: A Randomized Control Trial.

Background Postoperative management in patients undergoing craniotomy is unique and challenging. We utilized a population of patients who underwent bilateral extracranial-to-intracranial (EC-IC bypass) revascularization procedures for moyamoya disease and hypothesized that 1 gram (gm) of intravenous (IV) acetaminophen given immediately after intubation and again 45 minutes prior to the end of craniotomy may be more effective than saline in minimizing opiate consumption and decreasing pain scores. Methods In a double-blind, randomized, placebo-controlled crossover pilot study, 40 craniotomies in 20 patients were studied. A random number generator assigned patients to receive either 1 gram of IV acetaminophen or an equal volume of normal saline immediately after intubation and again 45 minutes prior to the end of their first operation. For the second surgery, patients received the study drug (IV acetaminophen or normal saline) that they did not receive during their first surgery. Results In the IV acetaminophen group, the average 24-hour postoperative fentanyl equivalent consumption was decreased but the difference was not statistically significant: 228 micrograms compared to 312 micrograms in the placebo group (Figure 1; p = 0.09). Pain scores did not significantly differ between the IV acetaminophen group and the placebo group in postoperative hours 0-12 (Figure 2; p = 0.44) or 24 (Figure 3; p = 0.77). Conclusion Our study demonstrates that in patients receiving bilateral craniotomies for moyamoya disease, IV acetaminophen when given immediately after intubation and again 45 minutes prior to closure does not significantly decrease 12- or 24-hour postoperative opiate consumption.

Frameless Robot-Assisted Deep Brain Stimulation Surgery: An Initial Experience.

BACKGROUND: Modern robotic-assist surgical systems have revolutionized stereotaxy for a variety of procedures by increasing operative efficiency while preserving and even improving accuracy and safety. However, experience with robotic systems in deep brain stimulation (DBS) surgery is scarce. OBJECTIVE: To present an initial series of DBS surgery performed utilizing a frameless robotic solution for image-guided stereotaxy, and report on operative efficiency, stereotactic accuracy, and complications. METHODS: This study included the initial 20 consecutive patients undergoing bilateral robot-assisted DBS. The prior 20 nonrobotic, frameless cohort of DBS cases was sampled as a baseline historic control. For both cohorts, patient demographic and clinical data were collected including postoperative complications. Intraoperative duration and number of Microelectrode recording (MER) and final lead passes were recorded. For the robot-assisted cohort, 2D radial errors were calculated. RESULTS: Mean case times (total operating room, anesthesia, and operative times) were all significantly decreased in the robot-assisted cohort (all P-values < .02) compared to frameless DBS. When looking at trends in case times, operative efficiency improved over time in the robot-assisted cohort across all time assessment points. Mean radial error in the robot-assisted cohort was 1.40 ± 0.11 mm, and mean depth error was 1.05 ± 0.18 mm. There was a significant decrease in the average number of MER passes in the robot-assisted cohort (1.05) compared to the nonrobotic cohort (1.45, P < .001). CONCLUSION: This is the first report of application of frameless robotic-assistance with the Mazor Renaissance platform (Mazor Robotics Ltd, Caesarea, Israel) for DBS surgery, and our findings reveal that an initial experience is safe and can have a positive impact on operative efficiency, accuracy, and safety.

Cerebral Oximetry Fails as a Monitor of Brain Perfusion in Cardiac Surgery: A Case Report.

Cerebral oximetry is commonly being advocated as a monitor for regional cerebral tissue oxygenation during cardiac surgery. We have increasing concern about the accuracy of this monitor, including the current systems entering the market, with new probes and algorithms. We present 2 cases where cerebral oximetry failed to accurately portray cerebral oxygenation. In the current form, cerebral oximetry may at best be an expensive tool without any benefit on outcomes. In addition, it may contribute to misleading and confusing clinical data.

The use of end-tidal argon to detect venous air embolism: foiled by "fake oxygen!"

Venous air-embolism (VAE) potentially catastrophic complication surgery. Based on previous data using changes in end-tidal nitrogen as an indicator of VAE, we surmised that changes in end-tidal argon (EtAr) may be an indicator of VAE. We sought to determine if a commercial mass-spectrometer (PCT Proline Analyzer 61700-8 Class 85, Ametek, Pittsburgh, PA 15238) could be used to detect changes in EtAr in an invitro model. A Drager Apollo™ (Drager, Lubeck, Germany) anesthesia machine was used to ventilate a dummy lung (2 L bag) with a minute ventilation of 6 L/min in 100% oxygen. The quadrupole mass-spectrometer (sampling at 0.0004 atm-cc/sec) was attached to the end-tidal inlet of the machine. Room air (1-60 mL) was injected into the dummy lung to simulate VAE. A strong baseline ion-current (1.2 × 10-12 amps) of argon was noted. Due to this contamination we were unable to detect "VAE" events of injected air. Argon represents approximately 0.93% of room air, or about 9300 parts per million (ppm). We detected about 2000 ppm argon in medical-grade oxygen (or 0.2%), limiting our ability to detect changes in EtAr. This is a USP-accepted contaminant, rendering this technology is insensitive for early, rapid detection of VAE. We assumed medical grade oxygen was pure and were surprised to learn otherwise. We want to share this likely largely unknown finding with the medical community.

Case Report of an Awake Craniotomy in a Patient With Eisenmenger Syndrome.

We present a detailed report of an awake craniotomy for recurrent third ventricular colloid cyst in a patient with severe pulmonary arterial hypertension in the setting of Eisenmenger syndrome, performed 6 weeks after we managed the same patient for a more conservative procedure. This patient has a high risk of perioperative mortality and may be particularly susceptible to perioperative hemodynamic changes or fluid shifts. The risks of general anesthesia induction and emergence must be balanced against the risks inherent in an awake craniotomy on a per case basis.

Ventriculoperitoneal Shunt Insertion Under Monitored Anesthesia Care in a Patient With Severe Pulmonary Hypertension.

A 32-year-old man with severe pulmonary arterial hypertension and Eisenmenger syndrome secondary to congenital ventricular septal defects presented for ventriculoperitoneal shunt insertion. Consultation between surgical and anesthesia teams acknowledged the extreme risk of performing this case, but given ongoing symptoms related to increased intracranial pressure from a large third ventricle colloid cyst, the case was deemed urgent. After a full discussion with the patient, including an explanation of anesthetic expectations and perioperative risks, the case was performed under monitored anesthesia care. Anesthetic management included high-flow nasal cannula oxygen with capnography and arterial blood pressure monitoring, dexmedetomidine infusion, boluses of midazolam and ketamine, and local anesthetic infiltration of the cranial and abdominal incisions as well as the catheter track. Hemodynamic support was provided with an epinephrine infusion, small vasopressin boluses, and inhaled nitric oxide. The patient recovered without any significant problems and was discharged home on postoperative day 3.

Extracorporeal membrane oxygenation for cardiac arrest during moyamoya cerebral revascularization surgery: case report.

The authors describe the case of a 51-year-old man with bilateral moyamoya disease and prior strokes who developed an asystolic cardiac arrest while undergoing revascularization surgery under mild hypothermia. The patient was successfully treated with venoarterial (VA) extracorporeal membrane oxygenation (ECMO) after manual cardiopulmonary resuscitation (CPR) was unsuccessful for 45 minutes. ECMO is a cardiopulmonary support system that is indicated for respiratory failure in pediatric and adult patients. It is increasingly being used as an extension to mechanical CPR for patients who have suffered cardiac arrest if the underlying cause of cardiac arrest is thought to be reversible. Identifying which patients should be placed on emergency ECMO after cardiac arrest is controversial given its high morbidity and mortality. ECMO in neurosurgical settings has associated risks of intracranial hemorrhage and neurological compromise, while resource utilization is paramount given the high costs of this treatment. This paper is significant because it describes the use of ECMO in an unindicated setting. Limited data are available for ECMO usage after cardiac arrest with baseline cerebral ischemia. Furthermore, this paper raises important considerations for extracorporeal CPR use in a patient who had recently undergone craniotomy. The patient in this report remained on ECMO for 48 hours, after which he was successfully weaned. He developed a pericardial effusion and compartment syndrome from the ECMO but made a complete neurological recovery. Use of ECMO emergently in an appropriately chosen neurosurgical patient is safe, even in the setting of baseline cerebral ischemia and recent craniotomy.

Multi-slice computed tomography assessment of bronchial compression with absent pulmonary valve.

BACKGROUND: Absent pulmonary valve is a rare cardiovascular anomaly that can result in profound tracheobronchial compression. OBJECTIVE: To demonstrate the advantage of multi-slice CT in diagnosing tracheobronchial compression, its severity as related to the adjacent dilated pulmonary arteries, and associated lung and cardiac lesions. MATERIALS AND METHODS: We included children with absent pulmonary valve who were reviewed by multi-slice CT during a 17-year period. The number and locations of stenoses and lung lesions were noted and the severity of stenosis was categorized. The diameter of the pulmonary artery was measured and associated cardiac defects were demonstrated. RESULTS: Thirty-one children (14 girls and 17 boys) were included. Of these, 29 had ventricular septal defect and 2 had an intact ventricular septum. Twenty-nine children (94%) had tracheobronchial compression, judged to be mild in nine children (31%), moderate in 10 (34%) and severe in 10 (34%). The different locations of the stenosis (carina, main bronchi, lobar and segmental bronchi) were observed. And the number and location of lung lesions demonstrated that the right middle and left upper and lower lobes were often affected. The diameter of the pulmonary artery in these children was well above normal published values, and Spearman rank correlation analysis showed a correlation between the size of the pulmonary artery and the severity of the tracheobronchial stenosis. Nineteen children (61%) underwent surgery and 4 of these children had a multi-slice CT post-operative follow-up study. CONCLUSION: Absent pulmonary valve can cause significant morbidity and mortality in children. Multi-slice CT can accurately depict areas of tracheobronchial compression, associated lung lesions and cardiac defects, helping to direct the surgeon.

Intraoperative cardiac arrest: was it the ACE inhibitor?

Continuing renin-angiotensin-aldosterone system antagonist therapy on the day of surgery is controversial, and appears to contribute to intraoperative hypotension. A patient presenting for cerebral aneurysm clipping continued her angiotensin-converting enzyme inhibitor on the morning of surgery, and subsequently experienced significant postinduction hypotension that culminated in cardiac arrest. Following successful resuscitation, she returned 6 weeks later to have her aneurysm clipped using identical anesthetic management; her blood pressure medications were held on the day of surgery.

Occurrence of severe hypotension after indocyanine green injection during the intraoperative period.

Indocyanine green (ICG) is generally considered to be safe for IV administration and has a very low incidence of complications. We report 2 cases of severe hypotension immediately after low dose administration of IV ICG. The first case is a 69-year-old woman who developed severe hypotension after a second 5 mg IV bolus of ICG given shortly after the placement of an aneurysm clip during an otherwise uneventful surgery performed under general anesthesia. The second case is a 56-year-old woman with moyamoya disease who became hypotensive subsequent to a 2.5 mg ICG bolus at the conclusion of an external-carotid to internal-carotid bypass procedure under general anesthesia. Anesthesiologists and surgeons are increasingly likely to encounter or request the intraoperative administration of ICG, and they need to be aware of this potential for an adverse reaction, particularly with the repeated doses. Anesthesia and other intraoperative conditions may mask the typically mild adverse reactions usually associated with ICG.

Human subthalamic neuron spiking exhibits subtle responses to sedatives.

BACKGROUND: During deep brain stimulation implant surgery, microelectrode recordings are used to map the location of targeted neurons. The effects produced by propofol or remifentanil on discharge activity of subthalamic neurons were studied intraoperatively to determine whether they alter neuronal activity. METHODS: Microelectrode recordings from 11 neurons, each from individual patients, were discriminated and analyzed before and after administration of either propofol or remifentanil. Subthalamic neurons in rat brain slices were recorded in patch-clamp to investigate cellular level effects. RESULTS: Neurons discharged at 42 ± 9 spikes/s (mean ± SD) and showed a common pattern of inhibition that lasted 4.3 ms. Unique discharge profiles were evident for each neuron, seen using joint-interval analysis. Propofol (intravenous bolus 0.3 mg/kg) produced sedation, with minor effects on discharge activity (less than 2.0% change in frequency). A prolongation of recurrent inhibition was evident from joint-interval analysis, and propofol's effect peaked within 2 min, with recovery evident at 10 min. Subthalamic neurons recorded in rat brain slices exhibited inhibitory synaptic currents that were prolonged by propofol (155%) but appeared to lack tonic inhibitory currents. Propofol did not alter membrane potential, membrane resistance, current-evoked discharge, or holding current during voltage clamp. Remifentanil (0.05 mg/kg) had little effect on overall subthalamic neuron discharge activity and did not prolong recurrent inhibition. CONCLUSIONS: These results help to characterize the circuit properties and feedback inhibition of subthalamic neurons and demonstrate that both propofol and remifentanil produce only minor alterations of subthalamic neuron discharge activity that should not interfere with deep brain stimulation implant surgery.

CT assessment of tracheobronchial anomaly in left pulmonary artery sling.

BACKGROUND: The left pulmonary artery sling (LPAS) is a rare vascular anomaly where the left pulmonary artery arises from the right pulmonary artery, passes over the right bronchus, and goes posteriorly between the trachea and esophagus. The LPAS is frequently associated with cardiac and non-cardiac defects including tracheobronchial abnormalities. OBJECTIVE: To evaluate the utility of multislice CT (MSCT) and helical CT (HCT) in diagnosing and defining the tracheobronchial anomaly and anatomic relationships between the trachea and aberrant left pulmonary artery. MATERIALS AND METHODS: MSCT or HCT was performed in 27 children to determine the tracheobronchial anatomy and identify tracheobronchial stenosis. Eighteen children underwent surgery. RESULTS: According to the Wells classification of LPAS, which includes two main types and two subtypes, there were eight cases of type 1A, five cases of type 1B, six cases of type 2A and eight cases of type 2B in this group. Twenty-four of the 27 children had substantial tracheobronchial stenosis. Four died before surgery; the 18 had reanastomosis of the left pulmonary artery. Five children also had tracheoplasty; three died after surgery. CONCLUSION: CT, especially MSCT, is an ideal modality for simultaneously identifying aberrant left pulmonary artery and any associated tracheobronchial anomaly. The Wells classification is useful for operative planning.

ECT in the treatment of a patient with catatonia: consent and complications.

Acute catatonia in an adolescent or young adult can present complex clinical challenges. Prominent issues include those involving diagnosis, timely and effective treatment, and diminished capacity to provide consent. The authors describe a 19-year-old woman presenting initially with manic excitement followed by a lengthy period of mutism, immobility, and food and fluid refusal. Elevated temperature, an elevated creatine phosphokinase level, and autonomic dysfunction led to consideration of a malignant catatonic syndrome. The patient manifested rigidity accompanied by posturing and waxy flexibility. Neurologic, medical, and laboratory evaluations failed to identify an organic cause for the likely catatonia. Treatment with amantadine, bromocriptine, and lorazepam was unsuccessful. ECT was deemed appropriate but required emergency guardianship because of the patient's inability to provide consent. At the initial ECT session, the elicited seizure was followed by an episode of torsade de pointes requiring immediate cardioversion. In reviewing the ECT complication, it appeared that muscle damage due to catatonic immobility led to acute hyperkalemia with the administration of succinylcholine. Discussions were held with the patient's guardian outlining the clinical issues and the risks of additional ECT. The patient responded to eight subsequent ECT sessions administered with rocuronium, a nondepolarizing muscle relaxant. The authors provide a brief review of the diagnosis and treatment of catatonia and address issues surrounding ECT, cardiac effects, use of muscle relaxants, and the consent process.

Does a delay in performing an activated clotting (ACT) test really matter? A study in nonheparinized blood and a single ACT machine.

Activating clotting time (ACT) is a point-of-care, blood clotting test used to monitor anticoagulation. Recently, institutional requirements have required that ACT testing be completed outside the operating room with trained, certified personnel other than anesthesia staff. For this reason, in this study, we looked at whether a delay in processing an ACT makes a significant difference to the ACT results. Twenty patients between 18 and 65 years of age consented to the study, each undergoing non-cardiac surgery, with no intraoperative administration of heparin. The study was approved by our Institutional Review Board. A blood sample was taken from the patient's arterial line in the operating room. Immediately afterward, 1 mL was placed into each of two ACT cartridges and the measurement was done in a Medtronic ACT2 machine. The first ACT value was 126.9 +/- 14.5 seconds. The ACT value at approximately 30 minutes was 108.3 +/- 20.3 seconds (p < .0001). The time between the first and last measurements was 29.4 +/- 3.0 minutes. The results suggest that the ACT values decrease over time between sampling all measurements. At approximately 30 minutes, the ACT values average 15% less than the control measurements. Therefore, it would seem prudent to determine ACT values immediately in the operating room without any delay, using point-of-care testing.