{"paper_id":"3774ffcc-b520-4986-82bd-22f03bd84e6e","body_text":"Awake craniotomy is a neurosurgical technique that allows real time assessment of neurological function during tumor resection, particularly when lesions are located in eloquent cortical areas [ 1 ]. The main objective is to maximize the extent of resection while preserving functions such as speech, motor control, and sensory processing. Successful performance of this surgical intervention requires meticulous anesthetic planning and patient cooperation [ 1 – 3 ].\nAnesthetic management plays a central role in ensuring patient comfort, key objectives include maintaining spontaneous ventilation, enabling adequate cooperation during cortical mapping, avoiding adverse events such as respiratory depression, nausea, vomiting, or seizures [ 1 – 3 ]. Monitored anesthesia care (MAC) combined with regional scalp block is commonly used; therefore, the selection of anesthetic agents with favorable profiles is essential [ 4 ]. Dexmedetomidine provides sedative, anxiolytic, and analgesic effects while preserving respiratory drive, making it. particularly suitable for awake craniotomy. When combined with remifentanil, it allows precise titration of sedation and analgesia through synergistic effects [ 5 – 7 ].\nBrain tumors located near or within eloquent regions represent clinical challenge, as surgical resection must balance oncological control with functional preservation. Awake craniotomy has therefore become the gold standard, enabling accurate intraoperative cortical mapping and direct patient participation [ 4 ,  7 ].\nDespite increasing global experience, there is limited research from low-middle-income countries (LMICS) [ 8 – 10 ]. The present study aims to describe our clinical experience with awake craniotomy following a multimodal strategy in a high-complexity Latin American Hospital, intending to contribute regional evidence and highlight the feasibility of implementing similar strategies in LMICs.\n\nWe conducted a retrospective observational descriptive study of adult patients (> 18 years), diagnosed with supratentorial tumors who underwent awake craniotomy for tumor resection at Clinica Imbanaco in Cali, Colombia between January and December 2024.\nThe Institutional Review Board of Pontificia Universidad Javeriana Cali and Clinica Imbanaco respectively approved the protocol of this study (Act No. 11 of 2024 under the code CEI-975). Given the retrospective nature of this research, informed consent was not required as it was classified as risk-free according to national resolution (No. 008430 of 1993, article 11, numeral A) of the Ministry of Health and Social Protection of Colombia.\n\nGeneral interventions include preoperative evaluation and patient preparation, including neuropsychological assessment of cognitive components, intraoperative anesthetic management and postoperative care carried out as follows:\nAll patients underwent pre-anesthetic consultation including physical, and neuropsychological evaluations. The assessments focused on airway examination and neurocognitive functions (language, memory, attention, motor and executive domains). Patients were counseled regarding the procedure, particularly the phases during which they would remain awake.\nStandard monitoring included electrocardiography (ECG), pulse oximetry, capnography, and non-invasive or invasive arterial blood pressure measurement. Intraoperative neuromonitoring was performed using cortical mapping with somatosensory and motor evoked potentials. Real-time neurological assessments during surgery focused on language and motor tasks coordinated with neurosurgical team to detect signs of deterioration.\nOxygen supplementation was provided via nasal cannula with exhaled CO2 monitoring (2–3 L/minute, titrated to patient needs). All patients received bilateral scalp block with 2–3 mL of local anesthetic (levobupivacaine 0.35%), prophylaxis against postoperative nausea and vomiting included dexamethasone (8-16 mg) and ondansetron (8 mg), with haloperidol selectively. Multimodal analgesia included a single dose of 1 gr of paracetamol and NSAID, unless contraindicated.\nOnce full monitoring is established, dexmedetomidine infusion was initiated at rates not exceeding 0.7 mcg/kg/h. Simultaneously, remifentanil was administered via target controlled infusion (TCI), using Minto pharmacokinetic model, titrated to effect-site concentrations of 0.5–2.5 ng/ml. Infusions were adjusted throughout the surgery according to the patients level of consciousness to ensure comfort, cooperation, spontaneous ventilation, and adequate conditions during each surgical stage (incision, craniotomy, cortical mapping, resection, and closure).\nBased on pharmacokinetic properties, dexmedetomidine was discontinued approximately 20 min before the end of surgery, and remifentanil 5–7 min before.\nFollowing surgery, patients were transferred to Neurosurgical Intensive Care Unit (NICU) for continuous neurological monitoring and postoperative neuroimaging to detect potential complications. Subsequently the patient is usually derived to the hospitalization unit hospital discharge.\nAll data were retrospectively obtained from institutional electronic medical records and recorded in Microsoft Excel ® . We included sociodemographic, preoperative and intraoperative clinical information.\nIntraoperative complications were defined according to institutional protocol. Cardiovascular complications included hypotension (≥ 20% decrease in systolic blood pressure compared with baseline), hypertension (systolic blood pressure > 140 mmHg), tachycardia (heart rate > 100 bpm), and bradycardia (heart rate < 60 bpm). Respiratory complications included desaturation (SpO₂ <92%) and apnea (temporary absence of spontaneous breathing). Neurological complications included seizures (loss of consciousness, repetitive or rhythmic movements of the head or extremities, and/or rigidity) and lack of cooperation during neuropsychological testing.\nQualitative variables were summarized using absolute and relative frequencies. For numerical variables, measures of central tendency and dispersion were chosen according to the distribution of the data. Normally distributed variables (e.g., age) were reported as mean ± standard deviation (SD), whereas non-normally distributed variables (e.g., tumor size) were reported as median and interquartile range (25th–75th percentiles). Only descriptive statistics were applied given the small sample size. Analysis was performed using Stata 18, (Stata Corp 2023).\nFor the description of categorical variables, absolute and relative frequencies were used to represent the distribution of the categories in a clear and understandable manner. In the case of numerical variables, robust measures of central tendency and dispersion were used, specifically the median and the interquartile range (IQR), since these allow a better representation of the data when the assumption of normality is not met.\n\nWe included fifteen patients during the study time. The mean age was 47.9 years. Most patients were male (60%) and of Latin-American mestizo ethnicity (86.67%). Regarding comorbidities, (66.7%) had a history of epilepsy as the sole diagnosis, while the remaining individuals presented epilepsy in association with other conditions (e.g., hypothyroidism, hypertension, HIV, latent tuberculosis). Additional reported comorbidities included fibromyalgia, ovarian cancer, Diabetes Mellitus, and glaucoma. Only one patient reported no comorbidities at all (Table  1 ).\nTable 1 Demographic and clinical profile of patients Variable N  = 15 Gender  Male 9 (60%)  Female 6 (40%) Age (years) 47.93 (12) Ethnicity  Afro-descendant 1 (6.7%)  White 1 (6.7%)  Latin-American Mestizo 13 (86.7%) Comorbidities  Epilepsy 10 (66.7%)  Hypertension 3 (20%)  Hypothyroidism 2 (13.3%)  Lidocaine allergy 1 (6.7%)  Ovarian cancer 1 (6.7%)  Diabetes 1 (6.7%)  Endometriosis 1 (6.7%)  Fibromyalgia 1 (6.7%)  Glaucoma 1 (6.7%)  Latent tuberculosis 1 (6.7%)  HIV 1 (6.7%)  No 1 (6.7%) n  (%); Mean (SD)\nDemographic and clinical profile of patients\nThere was a varied distribution in the location of the brain tumors, with a predominance of the right frontal (33.3%) and left frontal (26.7%) regions. The median size of the tumors was 29 mm, with a range that varied between 18 and 68 mm. Regarding preoperative neurological status, most patients (86.7%) had an optimal level of consciousness (Glasgow 15), while the remaining 13.3% showed a slight decrease in the scale with a score of 14 (Table  2 ).\nTable 2 Brain tumor distribution and preoperative neurological condition Variable N  = 15 Tumor location  Right frontal lobe 5 (33.3%)  Left frontal lobe 4 (26.7%)  Left parietal lobe 1 (6.7%)  Right temporal lobe 2 (13.3%)  Left temporal lobe 3 (20%)  Tumor size (mm) 29 (P25–P75) Preoperative neurological condition  Glasgow 14 2 (13.3%)  Glasgow 15 13 (86.7%) n  (%); Median (P25-P75)\nBrain tumor distribution and preoperative neurological condition\nAll patients underwent awake craniotomy under monitored anesthesia care. Scalp block was performed in all cases. The anesthetic regimen in all patients included continuous infusions of dexmedetomidine and remifentanil with variable target doses. Dexmedetomidine was administered at an infusion range between 0.1 and 0.5 mcg/kg/h combined with remifentanil at site effect concentrations between 0.5 and 2.0 ng/ml using Minto pharmacokinetic model for Target-controlled infusion (TCI), with two patients requiring higher remifentanil targets up to 2.5 ng/ml.\nRegarding analgesic management, all patients received at least one non-opioid analgesic: 40% received a combination of paracetamol and ketorolac, 26.67% received paracetamol and parecoxib, and 20% received paracetamol alone.\nAll patients received antiemetic prophylaxis with dexamethasone and ondansetron. In selected patients, haloperidol was included as part of the regimen for the prevention of postoperative nausea and vomiting. Additional medications were administered according to the anticipated intraoperative and postoperative needs. levetiracetam and lacosamide were used in most cases as seizures prophylaxis according to previously taken antiepileptic drugs (AEDs). Tranexamic acid was administered in several cases as patient blood management (PBM) strategy to minimize intraoperative and postoperative bleeding and reduce the need for transfusions. These medications were combined in various protocols tailored to individual patient characteristics and surgical considerations (Table  3 ).\nTable 3 Intraoperative clinical characteristics Variable N  = 15 Scalp block  Yes 15 (100%) Anesthetic technique used  Monitored Anesthesia Care (MAC) 15 (100%) Anesthetic agents administered  Dexmedetomidine 15 (100%)  Remifentanil 15 (100%) Dexmedetomidine (mcg/kg/h)  0.1–0.3 1.0 (6.7%)  0.1–0.5 9 (60%)  0.1–0.7 1 (6.7%)  0.2–0.5 1 (6.7%)  0.3–0.5 3 (20%) Remifentanil (ng/ml)  0.5-2 1 (6.7%)  0.6-2 1 (6.7%)  1–2 8 (53.3%)  1-2.2 1 (6.7%)  1 3 (20%)  2-2.5 1 (6.7%) Analgesic agents administered  Ketorolac 6 (40%)  No 2 (13.3%)  Paracetamol 13 (86.7%)  Parecoxib 4 (26.7%) Other pharmacological agents used  Tranexamic acid 14 (93.3%)  Dexamethasone 15 (100%)  Haloperidol 2 (13.3%)  Lacosamide 4 (26.7%)  Levetiracetam 10 (66.7%)  Ondansetron 15 (100%)  Surgery duration (minutes) 247.27 (74.10)  Anesthesia duration (minutes) 341.13 (78.93) n  (%); Mean (SD)\nIntraoperative clinical characteristics\nIntraoperative complications were infrequent in this cohort. Transient bradycardia occurred in 8 of the 15 patients. The minimum recorded heart rates ranged from 42 to 57 beats per minute without hemodynamic impact and need of vasopressor support. No respiratory or neurological complications were reported intraoperatively, and no failures of the awake craniotomy protocol were recorded. All procedures were completed successfully as planned (Table  4 ).\nTable 4 Intraoperative complications Variable N  = 15 Intraoperative cardiovascular complications  No 6 (40%)  Yes 9 (60%) Intraoperative bradycardia  Minimum HR 42 bpm 1 (6.7%)  Minimum HR 47 bpm 1 (6.7%)  Minimum HR 50 bpm 1 (6.7%)  Minimum HR 53 bpm 1 (6.7%)  Minimum HR 55 bpm 2 (13.3%)  Minimum HR 56 bpm 1 (6.7%)  Minimum HR 57 bpm 1 (6.7%) Intraoperative respiratory complications  No 15 (100%) Intraoperative neurological complications  No 15 (100%) Failed awake craniotomy  No 15 (100%) n  (%)\nIntraoperative complications\n\nIn our experience, all procedures were successfully completed under regional anesthesia (scalp block) and monitored anesthesia care with a combination of dexmedetomidine infusion and remifentanil delivered using a TCI system, without conversion to general anesthesia. Bradycardia was the most frequent cardiovascular event, likely related to the synergistic effect of the agents used. These episodes were transient and did not result in hemodynamic instability and required neither vasopressor support nor modifications to the anesthetic strategy. No respiratory or neurological complications were observed. This emphasizes the importance of careful titration, continuous monitoring, and trained teams to maintain patient safety throughout the different stages of awake craniotomy.\nOur results are consistent with previous reports supporting the use of dexmedetomidine as part of anesthetic strategies for awake craniotomy. Goettel et al. conducted a randomized controlled trial comparing dexmedetomidine with propofol–remifentanil for monitored anesthesia care in patients undergoing supratentorial tumor resection. No differences were found regarding sedation effectiveness or mapping quality, although dexmedetomidine was associated with fewer respiratory adverse effects and lower heart rate, without differences in the need for [ 7 ].\nIn addition, the use of dexmedetomidine in neurosurgical patients might have neuroprotective advantages with minimum impact in neuronal function, hemodynamic stability, and respiratory drive, allowing for stable intraoperative conditions ensuring patient cooperation and enhancing safety [ 5 ,  7 ].\nAnesthetic management in awake craniotomy does not have a standardized protocol, techniques to provide adequate analgesia and sedation levels can vary greatly among centers. The choice of sedative agents is based on several factors such as safety, availability and predictability of their effects on consciousness and intraoperative cortical mapping electrocorticography. Jose et al. described the use of Propofol, Remifentanil and Dexmedetomidine alone or in combination due to their pharmacokinetic profiles allowing rapid recovery and smooth emergence [ 8 ].\nAccordingly, to the sedative agents used in our study, it has been reported that Remifentanil for awake craniotomy is commonly used at 0.05 to 0.1 mcg/kg/min or between 2 and 3 ng/ml via TCI and Dexmedetomidine initially administered with an initial bolus of 1 mcg/kg for 10 min followed by an infusion from 0.2 to 0.7 mcg/kg/h [ 9 ]. Furthermore, Izzi et al. in 2024 also described the safety of using the combination of dexmedetomidine infusion at low dosages 0.7 mcg/kg/h and Remifentanil via TCI to the site effect with the Minto model between 0.5 and 1 ng/ml for conscious sedation in awake craniotomy [ 6 ].\nThus, the optimal combination of anesthetic agents used in AC continues to be a subject of debate. Aghajanian et al. conducted a systematic review highlighting the great variability in anesthetic protocols used in MAC for AC. Future research is required to draw definitive conclusions [ 10 ].\nMaintaining airway patency and avoiding respiratory depression and hypercapnia are essential in this type of neurosurgical intervention. McAuliffe et al. conducted a retrospective study including 55 patients who received scalp block and sedation with Dexmedetomidine infusion. This approach offered comfort and some degree of anxiolysis to patients undergoing awake craniotomy, allowing successful intraoperative neurological monitoring. No adverse events were reported related to critical airway manipulation or the need for general anesthesia [ 11 ]. The aforementioned is consistent with our results, where there was no need to intervene with the airway, and each procedure was performed successfully.\nEven though none of the patients included in our cohort presented intraoperative seizures, in the context of awake craniotomy, this neurological complication remains a significant concern due to cortical stimulation and tumor manipulation. The use of AEDs (e.g. Levetiracetam) for seizure control and prophylaxis has demonstrated efficacy and better tolerability according to previous studies, increasingly favored over phenytoin due to its low incidence of side effects, and lack of hepatic enzyme induction and minimal pharmacologic interactions being ideal in patients with a high burden of comorbidities or polypharmacy [ 12 ].\nAlthough the implementation of awake craniotomy for removing cerebral tumors in Latin American and LMICs remains full of challenges, our study, carried out in a high complexity hospital in Colombia, allows us to compare its favorable results with other institutions from LMICs. Albuquerque et al. conducted a prospective observational study including 51 patients from 18 to 70 years in Brazil, emphasizing the importance of a dedicated multidisciplinary team planning and performing these procedures on a regular basis to obtain good functional outcomes [ 13 ].\nAlthough most available reports on awake craniotomy come from high-income countries, evidence from Latin America and other LMICs is steadily increasing.In Brazil, a prospective observational study emphasized the role of a dedicated multidisciplinary team and regular performance of these procedures to ensure good outcomes [ 13 ,  14 ]. Our results add to this regional experience and show that awake craniotomy can also be safely performed in Colombia. Beyond Latin America, additional reports from India, Egypt, and Pakistan further confirm the feasibility and safety of this approach in different LMIC contexts, underscoring the global relevance of adapting anesthetic protocols to resource-limited settings [ 15 ].\nThe main limitation of our study is the retrospective nature of the study and the small sample size, and single center setting, which limit generalizability. Besides, our study was conducted at Clinica Imbanaco, which is one of the few high complexity institutions in the country that performs awake craniotomy and provides health care to a significant area of the southern territory of Colombia, a region primarily inhabited mainly by indigenous, afro descendant and mestizo populations. The low number of cases reflects the limited frequency with which this procedure is performed, even in high complexity centers.\nBy sharing our experience, our findings provide valuable evidence on performing awake craniotomy in LMICs. Moreover, this experience may serve as reference for other institutions in Latin America aiming to adopt similar protocols highlighting the absence of serious intraoperative complications.\nFor anesthesiologists and neurosurgical teams, this experience highlights the critical role of perioperative planning tailored to patient needs, with a focus on the safety and efficacy of regional anesthesia techniques and monitored anesthesia care. Future research should include prospective, multicenter studies with larger and more diverse populations to strengthen the evidence base. It will also be relevant to explore correlations between intraoperative spectrographic data and clinical variables during surgery that may allow assessment of long term functional, cognitive and quality of life outcomes, ideally carried out in comparable hospital settings.\n\nThe present experience highlights the importance of trained teams, well-defined protocols and anesthetic strategies adapted to the local context. Awake craniotomy was successfully performed in all patients using the combination of dexmedetomidine and remifentanil, without conversion to general anesthesia, cardiovascular interventions or respiratory or neurological complications. These findings may contribute to building regional references and support the safe adoption of awake craniotomy strategies in similar clinical settings.","source_license":"CC-BY-4.0","license_restricted":false}