Neurosurgical Anesthesiology

Perioperative Management of Direct Oral Anticoagulants in Intracranial Surgery The use of direct oral anticoagulants is increasing rapidly, because of perceived benefits over older agents, such as predictable pharmacokinetics and a reduced risk of bleeding. Elderly patients, who are more likely to be prescribed these drugs, are also presenting for neurosurgical procedures more often. The combination of these factors will result in neurosurgeons and neuroanesthesiologists encountering patients prescribed direct oral anticoagulants on an increasingly frequent basis. This review provides a summary of the current evidence pertaining to the perioperative management of these drugs, in the context of elective and emergency intracranial surgery. It highlights emerging therapies, including specific antidotes, as well as areas where the evidence base is likely to improve in the future. The authors have no funding or conflicts of interest to disclose. Address correspondence to: John Porter, MD, FRCA, FFICM, E-mail: johnporter@nhs.net. Received March 30, 2019 Accepted June 12, 2019 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Propofol But Not Desflurane Maintains Rat Cerebral Arteriolar Responses to Acetylcholine During Acute Hyperglycemia Background: Acute hyperglycemia causes vascular endothelial dysfunction in various organs including the cerebral vessels. It is associated with increased mortality and morbidity in the perioperative period. The impact of anesthetic agents on cerebral vasodilatory responses during hyperglycemia remains unclear. We investigated endothelial function in rat cerebral arterioles during acute hyperglycemia, under propofol or desflurane anesthesia. Materials and Methods: A closed cranial window preparation was used to measure changes in pial arteriole diameter induced by topical application of acetylcholine (ACh), an endothelium-dependent vasodilator, in rats anesthetized with propofol or desflurane. Pial arteriole responses to ACh were measured during normoglycemia and hyperglycemia. We then investigated whether the response of cerebral arterioles to acute hyperglycemia under propofol anesthesia were related to propofol or its vehicle, intralipid. Results: ACh resulted in a dose-dependent dilation of cerebral arterioles during propofol and desflurane anesthesia under normoglycemic conditions. The vasodilatory effects of ACh were also maintained under hyperglycemic conditions during propofol anesthesia, but the vasodilator response to ACh was significantly impaired during hyperglycemia compared with normoglycemia with desflurane anesthesia. The vasodilatory effects of ACh were maintained during normoglycemia and hyperglycemia in rats receiving propofol or intralipid. Conclusions: Rat pial arteriole responses to ACh are maintained during conditions of acute hyperglycemia with propofol anesthesia but suppressed compared with normoglycemia with desflurane anesthesia. Supported in part by a Grant-in-Aid for Scientific Research from Ministry of Education, Science and Culture of Japan (grant nos. 15K10509 and 17K11046). Part of this report was previously presented at the Annual Meeting of American Society of Anesthesiologists held in Boston on October 21, 2017. The authors have no conflicts of interest to disclose. Address correspondence to: Hiroki Iida, MD, PhD. E-mail: iida@gifu-u.ac.jp. Received March 19, 2019 Accepted June 19, 2019 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Noninvasive Intracranial Pressure Estimation With Transcranial Doppler: A Prospective Observational Study Background: Transcranial Doppler (TCD) ultrasonography has been described for the noninvasive assessment of intracranial pressure (ICP). This study investigates the relationship between standard, invasive intracranial pressure monitoring (ICPi) and noninvasive ICP assessment using a simple formula based on TCD-derived flow velocity (FV) and mean arterial blood pressure values (ICPTCD). Material and Methods: We performed a prospective observational study on 100 consecutive traumatic brain injury patients requiring invasive ICP monitoring, admitted to the Neurosciences and Trauma Critical Care Unit of Addenbrooke’s Hospital, Cambridge, UK. ICPi was compared with ICPTCD using a method based on the “diastolic velocity-derived estimator” (FVd), which was initially described for the noninvasive estimation of cerebral perfusion pressure but subsequently utilized for ICP assessment. Results: Median ICPi was 13 mm Hg (interquartile range: 10, 17.25 mm Hg). There was no correlation between ICPi and ICPTCD (R=−0.17; 95% confidence interval [CI]: −0.35, 0.03; P=0.097). Bland-Altman analysis demonstrated wide 95% limits of agreement between ICPi and ICPTCD (−27.58, 30.10; SD, 14.42). ICPTCD was not able to detect intracranial hypertension (ICPi >20 mm Hg); the area under the receiver operating characteristic curve for prediction was 34.5% (95% CI, 23.1%-45.9%) with 0% sensitivity and 74.4% specificity for ICPTCD to detect ICPi>20 mm Hg. Conclusions: Using a formula based on diastolic FV, TCD is an insufficiently accurate method for the noninvasive assessment of ICP. Further studies are warranted to confirm these results in a broader patient cohort. D.C. and C.R. have contributed equally. D.C. and M.C. are partially supported by NIHR Brain Injury Healthcare Technology Co-operative, Cambridge, UK. P.R. and E.B. are partially supported by the grant SIR RBSI14LOVD of the Italian Ministry of Education, University and Research. G.C. is a member of the speakers’ bureau of Integra-Codman, and he received funding for educational activities. The remaining authors have no conflicts of interest to disclose. Address correspondence to: Chiara Robba, MD, PhD, E-mail: kiarobba@gmail.com. Received February 15, 2019 Accepted May 28, 2019 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Abdominal Cerebrospinal Fluid Pseudocyst Due to Ventriculoperitoneal Shunt Mimicking Unilateral Pleural Effusion: A Rare Finding No abstract available

Continuous Near-Infrared Spectroscopy Monitoring in Adult Traumatic Brain Injury: A Systematic Review Near-infrared spectroscopy (NIRS) may provide a noninvasive way to monitor cerebral oxygenation in patients with traumatic brain injury, therein allowing for timely intervention aimed at reversing regional brain tissue hypoxia. We conducted a systematic review of NIRS-based oximetry measurements and their association with (A) patient functional outcome (B) other neurophysiological parameters. We searched MEDLINE, EMBASE, SCOPUS, BIOSIS, GlobalHealth and Cochrane Databases from inception to December 2018 and relevant conference proceedings published over the last 5 years. A total of 42 studies meeting our inclusion criteria were found (37 prospective observational, 5 retrospective designs). Seven studies reporting on the association between NIRS-based cerebral oxygenated hemoglobin measurements, mortality, modified Rankin Scale, Glasgow Outcome Scale, or Extended Glasgow Outcome Scale were identified. Forty-two studies exploring associations with neurophysiological parameters were included. Notwithstanding significant gaps in the currently available literature, our analysis suggests a link between NIRS-detected cerebral hypoxia during the acute phase of traumatic brain injury and poor functional outcome. NIRS measurements appear to reflect changes in intracranial pressure, invasively monitored brain tissue oxygen tension and various cerebrovascular reactivity indices although low quality contradicting data exist. More importantly, our review highlights the need for more prospective work before routine integration of NIRS-based techniques into multimodality monitoring regimen. F.M. has received salary support for dedicated research time from the Canada Cambridge Scholarship funded by the Cambridge Commonwealth Trust. F.A.Z. has received salary support for dedicated research time. Such salary support came from: the Cambridge Commonwealth Trust Scholarship and the University of Manitoba Clinician Investigator Program. F.A.Z.’s research program is supported through the University of Manitoba Thorlakson Chair in Surgical Research Establishment Fund. E.P.T. has received post-doctoral scholarships from the Swedish Society for Medical Research (Svenska Sällskapet för Medicinsk Forskning). The remaining authors have no funding or conflicts of interest to disclose. Address correspondence to: François Mathieu, MD, E-mail: fm494@cam.ac.uk. Received February 7, 2019 Accepted May 18, 2019 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Assessment of the ECG T-Wave in Patients With Subarachnoid Hemorrhage Background: Prolongation of the interval from the peak to the end of the T wave (Tp-Te) on a 12-lead electrocardiogram (ECG) is associated with ventricular arrhythmias. The aim of this study was to clarify associations between Tp-Te, Tp-Te/QT, and Tp-Te/rate-corrected QT (QTc) with clinical severity of subarachnoid hemorrhage (SAH) and clinical outcomes. Methods: This retrospective study included 222 patients with acute SAH (group S) and 306 patients with unruptured cerebral aneurysms (group U). Tp-Te, Tp-Te/QT, and Tp-Te/QTc were manually measured in standard 12-lead ECG recordings on admission and comparisons made between patients in groups S and U. The relationships of these ECG parameters with Hunt and Hess grade and Glasgow outcome scale were analyzed using multiple logistic regression analysis after adjustment for confounding factors. Results: Tp-Te, Tp-Te/QT, and Tp-Te/QTc were significantly greater in group S than in group U (group S: 109±30, 0.26±0.07, and 0.24±0.06 ms; group U: 84±12, 0.22±0.03, and 0.21±0.03 ms, respectively; P < 0.0001). In addition, in the multiple logistic regression analyses these variables were positively correlated with the Hunt and Hess grade (Tp-Te odds ratio [95% confidence interval], 2.414 [1.375-4.238], P=0.002; Tp-Te/QT, 1.886 [1.085-3.277], P = 0.024; Tp-Te/QTc, 1.873 [1.07-3.278], P=0.028, and negatively correlated with Glasgow outcome scale Tp-Te odds ratio [95% confidence interval], 4.168 [2.409-7.209], P<0.001; Tp-Te/QT, 2.434 [1.413-4.192], P=0.001; Tp-Te/QTc 2.953 [1.703-5.123], P<0.001). Conclusions: Tp-Te, Tp-Te/QT, and Tp-Te/QTc are associated with disease severity and clinical outcome in patients with SAH. The authors have no conflicts of interest to disclose. Address correspondence to: Toshifumi Takasusuki, MD, PhD. E-mail: takasusu@dokkyomed.ac.jp. Received October 3, 2018 Accepted May 30, 2019 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved

Postoperative Delirium and EEG Monitoring No abstract available

Response to Letter to the Editor From Lobo et al No abstract available

A Case of Malignant Cerebral Edema Following Removal of Infected Autologous Cranioplasty Flap No abstract available

A Prospective Randomized Trial Comparing Topical Intranasal Lidocaine and Levobupivacaine in Patients Undergoing Endoscopic Binostril Transnasal Transsphenoidal Resection of Pituitary Tumors Introduction: Local anesthetic intranasal packing is used in transnasal surgery to reduce hemodynamic fluctuations. We hypothesized that the long acting local anesthetic levobupivacaine would provide superior hemodynamic stability and postoperative analgesia compared with lidocaine in endoscopic transnasal transsphenoidal (TNTS) surgery. Materials and Methods: In this prospective, randomized, double-blind trial, 48 patients undergoing TNTS surgery were allocated to the 2 groups to receive preoperative intranasal packing with 15 mL of 1.5% lidocaine or 0.5% levobupivacaine each mixed with 60 mg ephedrine. Heart rate and mean arterial blood pressure were recorded immediately before induction of anesthesia, at various time points throughout surgery, and at tracheal extubation. Bleeding in the surgical field, time to extubation, and postoperative pain were also assessed. Results: There was no significant difference in heart rate between the lidocaine and levobupivacaine groups at any point. Mean arterial pressure was also similar between the 2 groups during surgery, whereas at extubation blood pressure was lower in the lidocaine compared with levobupivacaine group (85±10 vs. 96±16 mm Hg; P=0.0010). There were no differences between the 2 groups in the other outcome variables. Conclusions: Preoperative intranasal packing with 1.5% lidocaine or 0.5% levobupivacaine provide similar hemodynamic stability throughout TNTS. Lidocaine packing may be more advantageous for hemodynamic stability during extubation. The authors have no funding or conflicts of interest to disclose. Address correspondence to: Georgene Singh, MD, DM. E-mail: georgenesingh@gmail.com. Received January 10, 2018 Accepted May 9, 2019 Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved