Awake Craniotomy

Prospective Randomized Controlled Trial Comparing Anesthetic Management With Remimazolam Besylate and Flumazenil Versus Propofol During Awake Craniotomy Following an Asleep-awake-asleep Method

BACKGROUND

Awake craniotomy is performed to resect brain tumors in eloquent brain areas to maximize tumor reduction and minimize neurological damage. Evidence suggests that intraoperative anesthetic management of awake craniotomy with remimazolam is safe. We compared the time to arousal and efficacy of anesthetic management with remimazolam and propofol during awake craniotomy.

METHODS

In a single-institution randomized, prospective study, patients who underwent elective awake craniotomy were randomized to receive remimazolam and reversal with flumazenil (group R) or propofol (group P). The primary end point was time to awaken. Secondary end points were time to loss of consciousness during induction of anesthesia, the frequency of intraoperative complications (pain, hypertension, seizures, nausea, vomiting, and delayed arousal), and postoperative nausea and vomiting. Intraoperative task performance was assessed using a numerical rating scale (NRS) score.

RESULTS

Fifty-eight patients were recruited, of which 52 (26 in each group) were available for the efficacy analysis. Patients in group R had faster mean (±SD) arousal times than those in the P group (890.8±239.8 vs. 1075.4±317.5 s; P=0.013)and higher and more reliable intraoperative task performance (NRS score 8.81±1.50 vs. 7.69±2.36; P=0.043). There were no significant intraoperative complications.

CONCLUSIONS

Compared with propofol, remimazolam was associated with more rapid loss of consciousness and, after administration of flumazenil, with faster arousal times and improved intraoperative task performance.

Serum Concentration of Ropivacaine After Repeated Administration to Several Parts of the Head During Awake Craniotomy: A Prospective Cohort Study

Introduction

During awake craniotomy, effective use of local anesthetics, such as ropivacaine, is critical. Blood concentrations of ropivacaine after repeated administration over a short period during awake craniotomy have not been studied.

Materials and Methods

In this prospective cohort study, we evaluated serum concentrations of ropivacaine 15 min after each administration during awake craniotomy at Nagoya University Hospital between April 5, 2018 and August 31, 2019 to determine the safe dose. A total of 30 patients scheduled to undergo elective awake craniotomy were included. Patients were injected with 0.375% ropivacaine before the awake phase at the following points: scalp block (T1), headpin area (T2), skin incision area (T3), temporal muscle (T4), and dura mater (T5). Arterial blood samples were collected 15 min after ropivacaine administration. In addition to the blood concentrations of ropivacaine, complications during the awake phase were evaluated as secondary endpoints.

Results

The mean total dose of ropivacaine was 5.01 ± 0.68 mg/kg (maximum total dose: 6.30 mg/kg). The mean interval from T1 to T5 was 128.0 ± 17.7 min. The maximum serum concentration did not exceed the toxicity threshold of 4.3 μg/mL in any patient (mean serum concentration: T1, 1.23 ± 0.36 μg/mL; T5, 0.82 ± 0.26 μg/mL). No addiction symptoms were observed during awakening in any case.

Conclusion

Our results show that, in cases of awake craniotomy with repeated anesthetic administration, a total dose of up to 5.0 mg/kg is safe, without addiction symptoms. Relatively large amounts of ropivacaine can be safely injected during awake craniotomy.

An Update of Neuroanesthesia for Intraoperative Brain Mapping Craniotomy

The perioperative multidisciplinary team approach has probably been best exemplified by the care of awake craniotomy patients. Advancement in anesthesia and meticulous perioperative care has supported the safety and complexity of the surgical and mapping efforts in glioma resection. The discussions in this review will emphasize on anesthetic and perioperative management strategies to prevent complications and minimize their effects if they occur, including current practice guidelines in anesthesia, updates on the applications of anesthetic medications, and emerging devices. Planning the anesthetic and perioperative management is based on understanding the pharmacology of the medications, the goals of different stages of the surgery and mapping, and anticipating potential problems.

Comparing two airway management strategies for moderately sedated patients undergoing awake craniotomy: A single-blinded randomized controlled trial

BACKGROUND

In the monitored anesthesia care (MAC) setting for awake craniotomy (AC), maintaining airway patency in sedated patients remains challenging. This randomized controlled trial aimed to compare the validity of the below-epiglottis transnasal tube insertion (the tip of the tube placed between the epiglottis and vocal cords) and the nasopharyngeal airway (simulated by the above-epiglottis transnasal tube with the tip of the tube placed between the epiglottis and the free edge of the soft palate) with respect to maintaining upper airway patency for moderately sedated patients undergoing AC.

METHODS

Sixty patients scheduled for elective AC were randomized to receive below-epiglottis (n = 30) or above-epiglottis (n = 30) transnasal tube insertion before surgery. Moderate sedation was maintained in the pre- and post-awake phases. The primary outcome was the upper airway obstruction (UAO) remission rate (relieved obstructions after tube insertion/the total number of obstructions before tube insertion).

RESULTS

The UAO remission rate was higher in the below-epiglottis group [100% (12/12) vs 45% (5/11); P = .005]. The tidal volume values monitored through the tube were greater in the below-epiglottis group during the pre-awake phase (P < .001). End-tidal carbon dioxide (EtCO₂ ) monitored through the tube was higher in the below-epiglottis group at bone flap removal (P < .001). During the awake phase, patients' ability to speak was not impeded. No patient had serious complications related to the tube.

CONCLUSION

The below-epiglottis tube insertion is a more effective method to maintain upper airway patency than the nasopharyngeal airway for moderately sedated patients undergoing AC.

High-flow nasal cannula improves clinical efficacy of airway management in patients undergoing awake craniotomy

Background

Awake craniotomy requires specific sedation procedure in an awake patient who should be able to cooperate during the intraoperative neurological assessment. Currently, limited number of literatures on the application of high-flow nasal cannula (HFNC) in the anesthetic management for awake craniotomy has been reported. Hence, we carried out a prospective study to assess the safety and efficacy of humidified high-flow nasal cannula (HFNC) airway management in the patients undergoing awake craniotomy.

Methods

Sixty-five patients who underwent awake craniotomy were randomly assigned to use HFNC with oxygen flow rate at 40 L/min or 60 L/min, or nasopharynx airway (NPA) device in the anesthetic management. Data regarding airway management, intraoperative blood gas analysis, intracranial pressure, gastric antral volume, and adverse events were collected and analyzed.

Results

Patients using HFNC with oxygen flow rate at 40 or 60 L/min presented less airway obstruction and injuries. Patients with HFNC 60 L/min maintained longer awake time than the patients with NPA. While the intraoperative PaO₂ and SPO₂ were not significantly different between the HFNC and NPA groups, HFNC patients achieved higher PaO₂/FiO₂ than patients with NPA. There were no differences in Brain Relaxation Score and gastric antral volume among the three groups as well as before and after operation in any of the three groups.

Conclusion

HFNC was safe and effective for the patients during awake craniotomy.

Trial registration

Chinese Clinical Trial Registry, CHiCTR1800016621. Date of Registration: 12 June 2018.

Intraoperative Awakening from Endotracheal General Anesthesia for Brain Mapping with Tracheal Tube In Situ

Awake craniotomy (AC) is indicated to excise a lesion close to an eloquent area of the brain. Success of this procedure depends upon the patient’s active participation during the awake phase of the surgery, especially for brain mapping. Occasionally, a patient may refuse to remain awake during the surgical procedure and demand general anesthesia (GA). A 27-year-old male with uncontrolled seizures from recurrent brain tumor near motor area refused to consent for AC citing his past unpleasant experience; so, the decision to administer GA was taken. To avoid straining/coughing on tracheal tube, his airway was anesthetized with transtracheal xylocaine, bilateral superior laryngeal nerve block, and inflation of tracheal tube cuff with xylocaine. GA was maintained with sevoflurane, infusion of fentanyl, and rocuronium. To awaken him, anesthetics were discontinued and rocuronium antagonized with sugammadex. Intravenous lignocaine and midazolam were administered to supress cough reflex and produce amnesia, respectively. He tolerated the entire duration of 30 minutes of brain mapping with electrocorticography and neurological testing comfortably. Upon completion of brain mapping, GA was reintroduced and the lesion excised. The surgical outcome was good with no neurological deficit. When interviewed postoperatively, the patient had no recall of the awake phase.

Anaesthesiologist's Approach to Awake Craniotomy

Awake craniotomy, which was initially used for the surgical treatment of epilepsy, is performed for the resection of tumours in the vicinity of some eloquent areas of the cerebral cortex which is essential for language and motor functions. It is also performed for stereotactic brain biopsy, ventriculostomy, and supratentorial tumour resections. In some institutions, avoiding risks of general anaesthesia, shortened hospitalization and reduced use of hospital resources may be the other indications for awake craniotomy. Anaesthesiologists aim to provide safe and effective surgical status, maintaining a comfortable and pain-free condition for the patient during surgical procedure and prolonged stationary position and maintaining patient cooperation during intradural interventions. Providing anaesthesia for awake craniotomy require scalp blockage, specific sedation protocols and airway management. Long-acting local anaesthetic agents like bupivacaine or levobupivacaine are preferred. More commonly, propofol, dexmedetomidine and remifentanyl are used as sedative agents. A successful anaesthesia for awake craniotomy depends on the personal experience and detailed planning of the anaesthetic procedure. The aim of this review was to present an anaesthetic technique for awake craniotomy under the light of the literature.