Original Article Anesthesia for awake craniotomy: A retrospective study Prabhat Kumar Sinha, Thomas Koshy, P. Gayatri, V. Smitha, Mathew Abraham*, Ramesh Chandra Rathod Departments of Anesthesiology and *Neurosurgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India Context: Awake craniotomy is increasingly performed the of the tumor located in the eloquent areas of the brain world over. We share our experience of performing craniotomy or for localization and resection of seizure focus. The awake with our anesthetic protocol. Aims: To evaluate and challenge before the anesthesiologist is to provide analyze the anesthesia records of the patients who underwent adequate analgesia and sedation, hemodynamic and awake craniotomy at our institution. Settings and Design: respiratory stability and a safe airway, with awake, University teaching hospital, Retrospective study. Materials cooperative patients for neurological testing. and Methods: We reviewed records of the 42 consecutive In our institution, we have been performing awake patients who underwent awake craniotomy under conscious craniotomy for the last five years. The aim of the study sedation using Fentanyl and Propofol infusion until December is to analyze our data of anesthetic management of the 2005. The drugs were titrated (Bispectral monitoring was patients in whom awake craniotomy was performed at used in 16 patients) to facilitate intermittent intraoperative our institute until December 2005. neurological testing. All patients received scalp blocks with a mixture of bupivacaine and lignocaine with adrenaline. Materials and Methods Haloperidol and ondansetron were administered in all patients at induction of anesthesia. Results: All patients completed the We retrospectively reviewed the anesthetic management procedure. One patient each needed endotracheal intubation and incidence of complications of all patients who and LMA for airway control during closure, while another had undergone awake craniotomy (excluding patients required CPAP perioperatively because of desaturation to undergoing awake stereotactic procedures or open brain <80%. There was signiÞ cantly decreased use of anesthetics biopsies). The study was approved by our institute (P<0.001) and a trend towards reduction in complications for a confidential review of the patient notes, which (e.g. respiratory depression and deep sedation) (P>0.05) with were to be taken from medical record department. The the use of BIS as compared to without BIS. (www.medknow.com).Intraoperative anesthetic records, operation notes and the postoperative complications were hypertension (19%), tight brain (14.2%), notes were examined and the incidence of complications focal seizure (9.5%) respiratory depression (7.1%), deep [deep sedation (defined as drug-induced depression sedation (7.1%), tachycardia (7.1%) and bradycardia. of consciousness during which patients cannot be Two patientsThis desaturated PDFa site tois <95%.hosted available 23.8% bypatients forMedknow freeeasily downloadaroused Publications but respond from purposefully following developed transient neurological deÞ cits. The most frequent repeated or painful stimulation), hypertension (systolic postoperative complications were PONV (19%) and seizures blood pressure >30% of base value), tachycardia and (16.6%). Conclusions: With the use of advanced monitoring bradycardia (heart rate > 140 and < 50 bpm respectively), and newer anesthetics, awake craniotomy is a relatively safe respiratory depression (RR <8 breath/min), desaturation procedure with an accepted rate of complications. (SpO2 <95%) and nausea and vomiting (PONV)] was recorded. Any patient developing neurological deficits Key words: Anesthesia, awake craniotomy, bispectral index, (transient or permanent) was also noted. Transient complication, fentanyl, haloperidol, monitoring, propofol, neurological deficits (consist mainly of sensory or motor regional anesthesia, scalp block deficit) are defined as the neurological deficit, which is Presentation at a meeting: There is an increasing trend towards performing 51st Annual Conference of the Indian Society of Anesthesiologists, Bhubaneshwar, Orissa, India, December 2003 craniotomy awake. This is done either for resection Prabhat Kumar Sinha Department of Anesthesia and Perioperative Medicine, London Health Sciences Centre-University Hospital, The University of Western Ontario, London, Ontario, Canada, N6A 5A5. E-mail: [email protected] 376 Neurology India | October-December 2007 | Vol 55 | Issue 4 Sinha, et al.: A modiÞ ed anesthetic protocol for awake craniotomy either improved or recovered fully during the first six limit. Patients were induced with intravenous fentanyl weeks of follow-up. All other neurological deficits are (0.5-1.0 µg/kg), propofol (1-2 mg/kg) and midazolam (1- classified as permanent neurological deficits. Patients 2 mg) followed by infusion of fentanyl (0.5-2 µg/kg/hr) were selected for the surgery on the basis of their and propofol (1-5 mg/kg/hr). All patients also received requirement for awake craniotomy as well as patient’s intravenous haloperidol (2.5-5 mg) at induction. The affirmation to cooperate fully with the procedure. The drugs were so titrated to keep BIS value above 60 (if precise indications for surgery were (i) lesions near used) and to facilitate intraoperative neurological the eloquent cortex determined by MRI, (ii) patients testing without compromising patient’s airway and with overlap of functional areas with the lesion based respiration. Also, ondansetron (4 mg) was administered on fMRI, (iii) clinical evidence of functional overlap before start of surgery and at closure of the duramater. with lesions meant for resection, (iv) conditions where To treat tachycardia and/or hypertension, metoprolol an intentional but acceptable deficit is planned and was administered and anesthesia was deepened. (v) when an extra-operative stimulation (based on a Furthermore, intravenous diclofenac (50-75 mg)/ subdural grid) showed functional areas in or in close tramadol (50-100 mg) were administered as per patient’s proximity with epileptogenic zones. response to pain. Again local anesthetic was infiltrated Anesthesiologists involved with the procedure at skin incision site after closure of the dura. All patients visited these patients one day prior to surgery. The received antibiotic, corticosteroids, anti-epileptic main purpose of the preoperative visit included taking drugs and mannitol during the intraoperative period. patients into full confidence and a lengthy explanation Some patients required furosemide. Postoperative pain of the chronological sequence of the procedure and was controlled with intramuscular diclofenac and/or the points during which pain or discomfort might be intravenous tramadol. We used ‘conscious sedation’ experienced. Patients were kept fasted since midnight technique (in which use of drug(s) produce(s) a state of and were administered clonidine (4 µg/kg), ranitidine, depression of the CNS enabling treatment to be carried atenolol (25 mg) and double the dose of anticonvulsants out, but during which verbal contact with the patient orally in the morning, however, anticholinergics were is maintained throughout the period of sedation[1]) in avoided. Any cardiac medications were continued as all of our patients. usual. Data were analyzed (SPSS version 11.0) using student’s Preparation in the operating room involved making t-test and Fisher’s exact test wherever appropriate. A P the patient as comfortable as possible. Operating room value of < 0.05 was considered as significant. temperature was kept warm or alternatively, warming blanket/forced air warming device was used. O2 was Results started via nasal cannula (2-4 LPM), once patients arrived in the operating room, an intravenous cannula, Forty-two patients had undergone awake craniotomy. an arterial cannula in one of the radial(www.medknow.com). artery and a The pathological diagnosis, demographic and operative central venous catheter into the patient’s antecubital characteristics as well as complications are shown in vein were sited under local anesthesia. Patient was Tables 1, 2, 3 and 4. Of 42 patients, 11 were operated for further monitored with ECG, end tidal carbon dioxide refractory epilepsy while the rest for tumor resection. (EtCO2) pulseThis oximetry PDFa site (SpO is hosted2 ),available urine output by forMedknowand freeTwo patients download Publications required airway from intervention. One patient Bispectral index (BIS) (as per the availability). All needed continuous positive airway pressure (CPAP) patients were monitored with electrocorticography during surgery and up to 2h postoperatively. The most (ECoG), somatosensory evoked potential and direct frequent intraoperative complications observed were cortical stimulation, however, motor evoked potential hypertension and tight brain. was not used. Bispectral index was used in 16 patients. Use of Scalp nerve blocks were performed bilaterally in all propofol and fentanyl were significantly reduced where patients while awake by a mixture of 0.25% bupivacaine BIS was used as compared to no BIS group (P<0.001) and 1% lignocaine with 1: 200 000 adrenaline (2-5 ml [Table 5]. No patients in the BIS group had either at each infiltration site). The nerves infiltrated were respiratory depression or deep sedation. There was a supratrochlear and supraorbital, auriculotemporal, lack of statistical significance between the two groups greater and lesser occipital