Training anesthesiology residents in providing anesthesia for awake craniotomy: learning curves and estimate of needed case load.

STUDY OBJECTIVE: To measure the learning curves of residents in anesthesiology in providing anesthesia for awake craniotomy, and to estimate the case load needed to achieve a "good-excellent" level of competence. DESIGN: Prospective study. SETTING: Operating room of a university hospital. SUBJECTS: 7 volunteer residents in anesthesiology. MEASUREMENTS: Residents underwent a dedicated training program of clinical characteristics of anesthesia for awake craniotomy. The program was divided into three tasks: local anesthesia, sedation-analgesia, and intraoperative hemodynamic management. The learning curve for each resident for each task was recorded over 10 procedures. Quantitative assessment of the individual's ability was based on the resident's self-assessment score and the attending anesthesiologist's judgment, and rated by modified 12 mm Likert scale, reported ability score visual analog scale (VAS). This ability VAS score ranged from 1 to 12 (ie, very poor, mild, moderate, sufficient, good, excellent). The number of requests for advice also was recorded (ie, resident requests for practical help and theoretical notions to accomplish the procedures). MAIN RESULTS: Each task had a specific learning rate; the number of procedures necessary to achieve "good-excellent" ability with confidence, as determined by the recorded results, were 10 procedures for local anesthesia, 15 to 25 procedures for sedation-analgesia, and 20 to 30 procedures for intraoperative hemodynamic management. CONCLUSIONS: Awake craniotomy is an approach used increasingly in neuroanesthesia. A dedicated training program based on learning specific tasks and building confidence with essential features provides "good-excellent" ability.

Paraneoplastic limbic encephalitis in a patient with adenocarcinoma of the colon: a case report.

Paraneoplastic limbic encephalitis is a rare clinical entity characterized by the development of neuropsychiatric symptoms associated with malignancies. A case of a woman who presented to the Emergency Department with abdominal pain, hyperglycemia, and altered mental status is presented. After initial stabilization and correction of hyperglycemia the patient underwent emergency surgery. Laparotomy showed marked dilatation and gangrenous changes of the colon and tumor in the sigmoid colon. She was mechanically ventilated and remained ventilator-dependent for 42 days. Most of the time she was febrile; fever persisted with peaks up to 40° C despite various antibiotic treatments. On neurological examination, the patient was somnolent with left-sided hemiparesis. Magnetic resonance imaging (MRI) showed hyperintensities in both hippocampal areas, and electroencephalography (EEG) showed sharp-wave activity in the temporal lobes. Cerebrospinal fluid (CSF) examination showed slightly elevated protein levels, and laboratory assessments showed an elevated titer of anti-Yo antibodies. Although we do not have pathological confirmation of limbic encephalitis, the diagnosis of paraneoplastic limbic encephalitis was presumed on the basis of MRI findings, EEG abnormality, elevated CSF protein, positive anti YO antibodies, and neurological findings.

Effect of PaCO2, PETCO2, P(a-ET)CO2 and Regional Cortical Blood Flow on the Prognosis of Craniotomy Patients / 대한마취과학회지

BACKGROUND: Carbon dioxide is a potent cerebral vasodilator. The change of carbon dioxide partial pressure may influence the intracranial pressure and the patients' neurological outcome. There are few reports about the influence of end-tidal CO2 (ETCO2), arterial CO2 (PaCO2) and its pressure difference P(a-ET)CO2 during a craniotomy on the Glasgow coma scale (GCS) score for evaluation of neurological status. In this study, authors tried to discover the influence of PaCO2, PETCO2, and P(a-ET)CO2 on neurological outcome. METHODS: The data of PaCO2 and PETCO2 and P(a-ET)CO2 during a craniotomy was saved. The correlations between each parameter, the GCS score and rCoBF were analyzed. To prevent a direct effect on carbon dioxide tension, blood pressure and body temperature were maintained within a normal range. At the same time, we inserted a probe of the thermal diffusion flowmetry monitor in the subdural space to monitor the regional cortical cerebral blood flow (rCoBF). All the data was saved simultaneously, at the moment of dura closure. RESULTS: There was a fair correlation between the PaCO2 and PETCO2. A low PaCO2 level correlated well with a good GCS score but, not with PETCO2. The mean P(a-ET)CO2 value was 4.4 +/- 3.1 mmHg. The high P(a-ET)CO2 level correlated well with a poor GCS score. High rCoBF correlated well with a good GCS score. However, the changes of PaCO2 and PETCO2 showed no correlations with the rCoBF. CONCLUSIONS: As a result, if we decrease the PaCO2 level by hyperventilation and increase the rCoBF level through proper management during anesthesia, we can improve the patients' neurological outcome.

The Hemodynamic Effect of Nerve Block by Cranial Pinning in Brain Surgery Patients / 대한마취과학회지

BACKGROUND: It is already known that the cranial pinning causes a sudden increment of blood pressure and heart rate which is harmful especially in brain surgery patient. These changes may be reduced by local infiltration at the sites of cranial pinning. This study was designed to investigate the hemodynamic effects of nerve block by cranial pinning and compare them with the effects of local infiltration at the pinning site. METHODS: Forty patients of brain surgery with cranial pinning were involved. After general anesthesia with isoflurane and 50% N2O, they were divided into 2 groups randomly: the control group (n = 20), had local infiltration at each pinning site with 1% lidocaine 2 ml, and the study group (n = 20), had nerve block of the supraorbital, and supratrochlear, and postauricular branches of the great auricular nerve with lidocaine 2 ml, the auriculotemporal nerve with lidocaine 2.5 ml, and the greater and lesser occipital nerves with lidocaine 2.5 ml. The hemodynamic variables(systolic, diastolic, mean blood pressure, and heart rate) were measured at the 3 different points just before cranial pinning, and 1 min and 5 min after cranial pinning. RESULTS: The values of hemodynamic variables at 1 min after cranial pinning increased in both groups when compared with just before cranial pinning, but there was no difference between the two groups. The increased values at 1 min were not high clinically, and returned to the levels recorded before cranial pinning by the 5 min recording time in both groups. CONCLUSION: From these results, we concluded that nerve block could also reduced the harmful hemodynamic effect of cranial pinning.

On the Usefulness of Intravenous Anesthesia for Patients Undergoing Postoperative Radiologic Examination / 대한마취과학회지

BACKGROUND: In most brain operations, the endotracheal tube is kept in postoperatively for airway maintenance during radiologic examinations. But the endotracheal tube causes tracheal irritation and hemodynamic changes. Inhalation anesthetics can not be administered during transport, and minimal concentration is exhaled for several hours after the end of inhalation. The present study was designed : (1) to determine the end tidal isoflurane concentration after the end of administration ; (2) to investigate the effects of intravenous anesthetics in patients with tracheal intubation during radiologic examination postoperatively. METHODS: We selected forty adult patients who were scheduled for elective neurosurgical operation with postoperative brain CT (computerized tomography). The study was performed in 2 steps; in the step 1 (n = 10), end tidal isoflurane concentration was checked after ending inhalation. In the step 2 (n = 30), patients were divided into one of three groups according to anesthesia method; group I (using isoflurane), group P (change from isoflurane to propofol about an hour before operation end), group M (using midazolam instead of propofol, compared to group P). In each group, the frequency of bucking and incidence of hypertension were checked during postoperative radiologic examinations. RESULTS: Minimal concentrations of isoflurane were detected in exhaled gas for about 2 hours after the end of isoflurane inhalation. The frequency of bucking was significantly lower in the group P and M than in group I (P = 0.002). In group P, the incidence of hypertension was significantly reduced compared to group M and I (P = 0.031). CONCLUSIONS: These results suggest that the change of anesthetic technique (from inhalation to intravenous) in the late period of operation, provides postoperative hemodynamic stability, a more comfortable state and minimal environmental pollution in comparison to inhalation anesthesia only.

On the Usefulness of Intravenous Anesthesia for Patients Undergoing Postoperative Radiologic Examination / 대한마취과학회지

BACKGROUND: In most brain operations, the endotracheal tube is kept in postoperatively for airway maintenance during radiologic examinations. But the endotracheal tube causes tracheal irritation and hemodynamic changes. Inhalation anesthetics can not be administered during transport, and minimal concentration is exhaled for several hours after the end of inhalation. The present study was designed : (1) to determine the end tidal isoflurane concentration after the end of administration ; (2) to investigate the effects of intravenous anesthetics in patients with tracheal intubation during radiologic examination postoperatively. METHODS: We selected forty adult patients who were scheduled for elective neurosurgical operation with postoperative brain CT (computerized tomography). The study was performed in 2 steps; in the step 1 (n = 10), end tidal isoflurane concentration was checked after ending inhalation. In the step 2 (n = 30), patients were divided into one of three groups according to anesthesia method; group I (using isoflurane), group P (change from isoflurane to propofol about an hour before operation end), group M (using midazolam instead of propofol, compared to group P). In each group, the frequency of bucking and incidence of hypertension were checked during postoperative radiologic examinations. RESULTS: Minimal concentrations of isoflurane were detected in exhaled gas for about 2 hours after the end of isoflurane inhalation. The frequency of bucking was significantly lower in the group P and M than in group I (P = 0.002). In group P, the incidence of hypertension was significantly reduced compared to group M and I (P = 0.031). CONCLUSIONS: These results suggest that the change of anesthetic technique (from inhalation to intravenous) in the late period of operation, provides postoperative hemodynamic stability, a more comfortable state and minimal environmental pollution in comparison to inhalation anesthesia only.

Anesthetic Management for Language Area Mapping with Laryngeal Mask Airway: A case report / 대한마취과학회지

Epilepsy surgery is performed in patients with epilepsy of focal origin and seizures which are refractory to medical treatment. Electrophysiologic mapping of the epileptic foci and other cortical areas (e.g., language, memory, sensorimotor) is frequently used to maximize the resection of the epileptogenic lesion while minimizing the neurologic deficits. For language area mapping, general endotracheal anesthesia can not be used because a patient can not vocalize. So awake craniotomy is frequently used. However, during awake craniotomy for language area mapping with local infiltration anesthesia and intravenous sedation and narcotics supplementation analgesia, respiratory arrest or depression and hypoxemia may occur. The airway securement is crucial to the patients. As an alternative to tracheal tubes, laryngeal mask airway can secure the airway and does not interference the vocalization. We could successfully performed the language area mapping in a 17-year-old male patient with laryngeal mask airway under deep intravenous anesthesia with local infiltration anesthesia of the scalp.

Anesthetic Management for Language Area Mapping with Laryngeal Mask Airway: A case report / 대한마취과학회지

Epilepsy surgery is performed in patients with epilepsy of focal origin and seizures which are refractory to medical treatment. Electrophysiologic mapping of the epileptic foci and other cortical areas (e.g., language, memory, sensorimotor) is frequently used to maximize the resection of the epileptogenic lesion while minimizing the neurologic deficits. For language area mapping, general endotracheal anesthesia can not be used because a patient can not vocalize. So awake craniotomy is frequently used. However, during awake craniotomy for language area mapping with local infiltration anesthesia and intravenous sedation and narcotics supplementation analgesia, respiratory arrest or depression and hypoxemia may occur. The airway securement is crucial to the patients. As an alternative to tracheal tubes, laryngeal mask airway can secure the airway and does not interference the vocalization. We could successfully performed the language area mapping in a 17-year-old male patient with laryngeal mask airway under deep intravenous anesthesia with local infiltration anesthesia of the scalp.

The Comparison of the Anesthetic Regimens for Functional Direct Cortical Stimulation Mapping during Craniotomy / 대한마취과학회지

BACKGROUND: Recently, functional direct cortical stimulation mapping is frequently used during craniotomy for the surgery of brain pathology (tumors, epileptic foci etc.) within or close to the central motor area. We reviewed and analyzed our experiences to evaluate the safety and efficacy of our hospital's anesthetic management regimens. METHODS: We used three anesthetic regimens (isoflurane fentanyl; propofol fentanyl; awake craniotomy, conscious sedation analgesia) in 44 patients. We evaluated the success ratio of mapping and the incidence of intraoperative problems (seizures, changes in vital signs etc) in each regimens. RESULTS: In awake craniotomy group, functional mapping is performed successfully in all patients but there were some intraoperative problems (hypertension; 3 in 11 patients, hypercapnia; 3 in 11 patients, change to general anesthesia required; 1 in 12 patients). In general anesthesia groups, there were no significant differences between isoflurane treated patients and propofol treated patients in the success ratio of mapping (17/20 vs 11/12) and the incidence of intraoperative problems (seizure; 3/20 vs 1/12, hypertension; 2/20 vs 1/12). CONCLUSION: This results suggest that the anesthetic management regimens used in our hospital provide suitable conditions for craniotomies when brain mapping is required.