Anesthetic management for interventional neuroradiology

With the field of neuroradiological procedures consistently expanding, breaking the border between the medical and surgical treatment, anesthetic involvement in those procedures is also increasing, which underscores the importance of related anesthesia management. The objective of this study is to review the closing or open endovascular procedures for intracranial aneurysm, arteriovenous malformation, acute ischemic stroke, and carotid stenosis and related anesthetic implications.

Combination of Electroconvulsive Therapy and Clozapine in Treatment-Resistant Schizophrenia

OBJECTIVE: This study aimed to investigate the effectiveness and tolerability of the combination of electroconvulsive therapy (ECT) in patients with clozapine-treated schizophrenia. METHODS: Patients with clozapine-treated schizophrenia during five years of pre-determined period were recruited from Electronic Medical Record. Clinical effects of acute ECT on psychotic symptoms were investigated. We also tried to identify predictive variables requiring maintenance treatment of ECT. RESULTS: Fourteen patients received ECT and clozapine and sixteen were treated with clozapine alone. In the ECT group, which could be refined as clozapine-resistance, PANSS total score was significantly reduced by 19.0±9.9 points, corresponding to a reduction rate of 18.5±8.3%. The clinical remission defined as 20% PANSS reduction criteria was achieved at 42.9%. The subscale factors were significantly reduced, among which the negative symptom was the least. There was no difference in demographic and clinical information between patients receiving and not receiving maintenance ECT, and not all patients seemed to need maintenance ECT if clozapine is continued. CONCLUSION: Combination of ECT and clozapine in patients with clozapine-resistant schizophrenia resulted in a rapid and substantial reduction of psychotic symptoms. Further studies are needed to improve the effectiveness and tolerability of ECT.

Practical Considerations in Anesthesia for Electroconvulsive Therapy

Electroconvulsive therapy (ECT) has been recognized effective as primary or secondary treatments for major psychiatric disorders including depression and schizophrenia, as well as psychiatric emergency such as suicide, food refusal and catatonia, and so on. Medicines used in anesthetic induction for ECT, cause various reactions in autonomous, hemodynamic, and neuromuscular systems. The anesthetics also affect the duration, threshold, and intensity of seizures evoked with electric stimuli, and thus modify the seizure quality in ECT. Individual characteristics of age, sex, weight, comorbid physical disorders, and medications should also be considered for optimal clinical response after ECT. When preparing for anesthesia, adequate anesthetic agents and muscle relaxants, and rapid recovery should be carefully considered. We conducted a case-series study to address practical issues that are frequently encountered during ECT anesthesia with reviews of updated journals in order to provide practical helps to clinicians who are preparing ECT for their patients.

Delirium in the intensive care unit / 대한마취과학회지

Delirium is a serious complication that commonly occurs in critically ill patients in the intensive care unit (ICU). Delirium is frequently unrecognized or missed despite its high incidence and prevalence, and leads to poor clinical outcomes and an increased cost by increasing morbidity, mortality, and hospital and ICU length of stay. Although its pathophysiology is poorly understood, numerous risk factors for delirium have been suggested. To improve clinical outcomes, it is crucial to perform preventive measures against delirium, to detect delirium early using valid and reliable screening tools, and to treat the underlying causes or hazard symptoms of delirium in a timely manner.

Hyperventilation delays clinical induction of desflurane

BACKGROUND: Ventilation is a major determinant of the alveolar concentration of inhaled anesthetics. Hyperventilation accelerates the equilibration of anesthetic in the lungs, but decelerates it in the brain. We evaluated this phenomenon for desflurane. METHODS: Twenty healthy subjects were enrolled after IRB approval. End-tidal concentrations of desflurane (P.DESF) were recorded during 10 minutes of mask induction with 8% desflurane. P.DESF was modeled with time and end-tidal concentrations of CO2 (P.ETCO2) using a two-exponential pharmacokinetic equation. Bispectral index (BIS) values were also measured to find out the component reflecting the cerebral concentration of desflurane. RESULTS: During induction, the rise of P.DESF could be separated into two components: early and late rises. Individual BIS values showed a higher correlation with the late component of P.DESF (P = 0.000). P.ETCO2 had two different effects on the rise of P.DESF. CONCLUSIONS: Hyperventilation hastened the early rise and delayed the late rise of P.DESF (P = 0.00, P = 0.00). Hyperventilation should be avoided to obtain rapid anesthesia induction with desflurane.

Hypocapnia Attenuates, and Nitrous Oxide Disturbs the Cerebral Oximetric Response to the Rapid Introduction of Desflurane

The aim of this study was to develop a nonlinear mixed-effects model for the increase in cerebral oximetry (rSO2) during the rapid introduction of desflurane, and to determine the effect of hypocapnia and N2O on the model. Twelve American Society of Anesthesiologist physical status class 1 and 2 subjects were allocated randomly into an Air and N2O group. After inducing anesthesia, desflurane was then increased abruptly from 4.0 to 12.0%. The PET(CO2), PET(DESF) and rSO2 were recorded at 12 predetermined periods for the following 10 min. The maximum increase in rSO2 reached +24-25% during normocapnia. The increase in rSO2 could be fitted to a four parameter logistic equation as a function of the logarithm of PET(DESF). Hypocapnia reduced the maximum response of rSO2, shifted the EC50 to the right, and increased the slope in the Air group. N2O shifted the EC50 to the right, and reduced the slope leaving the maximum rSO2 unchanged. The N2O-effects disappeared during hypocapnia. The cerebrovascular reactivity of rSO2 to CO2 is still preserved during the rapid introduction of desflurane. N2O slows the response of rSO2. Hypocapnia overwhelms all the effects of N2O.

Analysis of factors related to patient refusal of spinal anesthesia / 대한마취과학회지

BACKGROUND: Spinal anesthesia is a anesthetic technique that can be easily used and practically applied according to patient's preference and physiologic status, surgical procedures and so forth. The purpose of the present study is to analyze factors related to patient refusal of spinal anesthesia, arising from the previous spinal anesthesia experience associated with side effects or unsatisfactory senses after spinal anesthesia. METHODS: One hundred ninety four patients undergoing various surgical procedures under spinal anesthesia were enrolled. We made a questionnaire that consisted of examination items and question items, and checked it during spinal anesthesia and about 24 hours after spinal anesthesia. Factors related to patient refusal of spinal anesthesia were analyzed with multiple logistic regression. RESULTS: Thirty one out of 194 patients (16%) rejected to receive spinal anesthesia if they would have chance to have it again. Significant factors associated with refusal of spinal anesthesia were low back pain (P = 0.005), needle type (Quincke) (P = 0.025) and tingling sensation in the lower extremities immediately after spinal anesthesia induction (P = 0.003). Low back pain was significantly associated with the number of attempts of spinal block (P = 0.023). CONCLUSIONS: Factors related to patient refusal of spinal anesthesia are low back pain, needle type and tingling sensation. Low back pain is related to the number of attempts of spinal block. Practitioners should give patients appropriate information about spinal anesthesia preoperatively and consider using Whitacre needle and avoid multiple attempts of spinal block so as to increase patient's compliance with spinal anesthesia.

Pulmonary edema during hysteroscopic surgery: Three cases report / 대한마취과학회지

Hysteroscopic surgery has become a routine gynecologic procedure. The advantages are associated with more accurate removal of lesion, its short operating time, rapid post-operative recovery and low morbidity. However, there are potentially serious complications which can be occured during and following hysteroscopic surgery. The complications are uterine perforation, fluid overload and electrolyte disturbance due to intravasation and absorption of uterine distention media, hemorrhage and, rarely, gas or air embolism. We experienced pulmonary edema during hysteroscopic surgery in three consecutive patients. Therefore, we report these cases of fluid overload with uterine distention media resulting acute pulmonary edema during hysteroscopic surgery.

Difficult endotracheal intubation due to an undiagnosed epiglottic cyst :A case report / 대한마취과학회지

An epiglottic cyst is a common form of laryngeal cysts which are rare causes of upper airway obstruction. A congenital laryngeal cyst always causes neonatal respiratory distress, but an acquired cyst shows very wide spectrum of symptoms such as no specific complaints, dysphagia, respiratory difficulty, or even death according to its size, location, or age. From anesthesiologists' point of view, an asymptomatic undiagnosed laryngeal cyst is a major concern. Unexpectedly, it can cause difficult airway such as 'cannnot intubate' or 'cannot intubate and cannot ventilate' situation during anesthesia. Recently we discovered an undiagnosed epiglottic cyst obscuring laryngeal inlet, leading to difficult intubation during general anesthesia for decompression and fusion of lumbar vertebrae. Fortunately, mask ventilation was possible, and after failed attempts of direct laryngoscopy, we could perform oral fiberoptic bronchoscope-aided intubation. He was discharged 10 days later with no harmful events.

Effect-site concentration of remifentanil for smooth tracheal intubation without muscle relaxants provokes hypotension under desflurane anesthesia / 대한마취과학회지

BACKGROUND: Many reports with hypnotics and opiates have been published for nonrelaxant tracheal intubation.In addition to its immediate onset and short duration time, remifentanil can well prevent responses against short and strong stimulation like tracheal intubation.However, the high concentration of remifentanil for nonrelaxant tracheal intubation can cause hemodynamic instability, thus we tried to estimate the predicted effect-site concentration of remifentanil for smooth intubation and provoking hypotension. METHODS: Forty three ASA I and II patients were randomly selected to receive an effect-site-controlled infusion of remifentanil 0, 2, 4, 6 ng/ml and propofol 2 mg/kg.Trachea was intubated after 3 minutes of manual breathing support with desflurane 6 vol%. The vital signs, end-tidal concentration of desflurane and responses of patients were recorded before intubation for 3 minutes and until 2 minutes after intubation every minute.The effective effect-site concentration (ECe) was calculated at 95% successful rate of smooth intubation and at 50% of provoking hypotension (equal to or under 55 mmHg). RESULTS: The estimation results of the logistic regression stated that 95% ECe of remifentanil for smooth intubation was 8.0 (5.0-14.3) ng/ml and 50% ECe for provoking hypotension equal to or under 55 mmHg before intubation was 5.0 (2.6-9.7) ng/ml. CONCLUSIONS: Remifentanil at 8.0 ng/ml provided good conditions for smooth intubation without muscle relaxants but could provoked hypotension.Consequently, we recommend the careful observation of the blood pressure with the use of remifentanil and the evaluation of the suitable measures to maintain the blood pressure for nonrelaxant tracheal intubation.

The effect of carbon dioxide pneumoperitoneum on baroreflex sensitivity / 대한마취과학회지

BACKGROUND: To determine if positive pressure pneumoperitoneum has adverse effects on autonomic nervous system function, we examined baroreflex sensitivity (BRS) during carbon dioxide pneumoperitoneum in patients undergoing laparoscopic surgery. METHODS: Twenty adult patients scheduled for laparoscopic gynecologic surgery were selected for the study. After general anesthesia was induced with sevoflurane, continuous electrocardiography and blood pressure were monitored. Spontaneous BRS was achieved using sequence method immediately before, and 5 minutes after, pneumoperitoneum. Heart rate variability (HRV) was also determined. RESULTS: After pneumoperitoneum, BRS decreased from 12.9 +/- 1.8 ms/mmHg to 8.1 +/- 1.1 ms/mmHg (P < 0.05), and the power of the high frequency band decreased from 237.8 ms2/Hz to 49.6 ms2/Hz (P < 0.05). CONCLUSIONS: Compared to recordings obtained before pneumoperitoneum, BRS was decreased during pneumoperitoneum. This may predispose patients undergoing laparoscopic surgery to hemodynamic instability in addition to pneumoperitoneum itself.