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.

Effectiveness of Electroconvulsive Therapy Augmentation on Clozapine-Resistant Schizophrenia

OBJECTIVE: This retrospective case series study of the effectiveness of electroconvulsive therapy (ECT) augmentation on clozapine-resistant schizophrenia was conducted by EMR review. METHODS: Clozapine-resistance was defined as persistent psychotic symptoms despite at least 12 weeks of clozapine administration with blood levels over 350 ng/mL in order to rule out pseudo-resistance. Seven in-patients who were taking clozapine and treated with ECT were selected. We analyzed the psychopathology and subscales changed by ECT. RESULTS: The average number of ECT sessions was 13.4 (±4.6). Total Positive and Negative Syndrome Scale (PANSS) score was significantly reduced by 17.9 (±12.8) points (p=0.0384) on average, which represented a reduction of 25.5% (±14.3). 71.4% (5/7) of patients were identified as clinical remission, with at least a 20% reduction in PANSS score. PANSS reduction was associated with number of ECT sessions, stimulus level in the final session, and blood clozapine levels before ECT. However, the negative subscale on the PANSS were not reduced by ECT in any patient. We did not observe any persistent adverse cognitive effects. CONCLUSION: This study supports that ECT augmentation on clozapine-resistant schizophrenia reveals clinically effective and safe. Further research should be done involving a larger number of patients to investigate the effectiveness of clozapine/ECT combination therapy.

Influence of acute normovolemic hemodilution on the potency and time course of action of rocuronium in rabbits

BACKGROUND: We performed this study to evaluate the potency and time course of rocuronium-induced neuromuscular block following moderate or severe acute normovolemic hemodilution (ANH) in rabbits. METHODS: Forty five rabbits were randomly assigned to the control (C) group, the moderate ANH (M) group, or the severe ANH (S) group. After stabilization of sevoflurane anesthesia, ANH was achieved by drainage of arterial blood and an intravenous infusion of 6% hydroxyethyl starch, during which hematocrit (Hct) decreased to 26.2 ± 2.5% in the M group and 17.6 ± 2.2% in the S group. We determined dose-response relationships of rocuronium in the three groups and created a time course of the action of 0.6 mg/kg rocuronium. RESULTS: The 50% effective dose (ED50) for rocuronium was 45% and 50% lower in the M and S groups, respectively, than in the C group (50.9 ± 6.3 µg/kg) (P < 0.001). The onset time after 0.6 mg/kg rocuronium was faster in the ANH groups compared with the C group (P < 0.001). The duration of neuromuscular block was prolonged by 38% and 43% in the M and S groups, respectively, compared with the C group (49.1 ± 6.9 min) (P < 0.001). CONCLUSIONS: ANH resulted in high potency, rapid onset, and prolonged duration of rocuronium. However, the severity of ANH did not alter the potency and duration of action of rocuronium.

Pharmacological and non-pharmacological intervention for rocuronium-induced withdrawal movement in the Korean population: a meta-analysis of 41 studies including 4,742 subjects / 대한마취과학회지

BACKGROUND: We purposed to systemically review studies investigating the prophylactic effect of both pharmacological and non-pharmacological modalities against rocuronium induced withdrawal movement (RIWM) in the Korean population. METHODS: Literature search was performed using MEDLINE, EMBASE, CENTRAL, Koreamed, KMBASE, KISS and RISS up to March 2014. Randomized controlled trials (RCTs) comparing pharmacological and non-pharmacological interventions with placebo aimed for the Korean population were included. Outcome measures were the incidence and severity of RIWM. We conducted subgroup analyses according to each intervention method. RESULTS: Data were analyzed from 41 RCTs totaling 4,742 subjects. The overall incidence of RIWM was about 80% (range 56-100%). Incidence and severity of RIWM were significantly reduced with lidocaine (risk ratio [RR] 0.60, 95% CI 0.49-0.74; standardized mean difference [SMD] -0.74, 95% CI -1.05 to -0.44), opioids (RR 0.28, 95% CI 0.18-0.44; SMD -1.71, 95% CI -2.09 to -1.34) and hypnotics (RR 0.36, 95% CI 0.25-0.52; SMD -2.20, 95% CI -2.62 to -1.79). Regardless of tourniquet use, lidocaine showed a prophylactic effect against incidence and severity of RIWM: tourniquet (RR 0.36, 95% CI 0.21-0.62; SMD -1.51, 95% CI -2.15 to -0.86); non-tourniquet (RR 0.58, 95% CI 0.47-0.71; SMD -0.74, 95% CI -1.05 to -0.44). Dilution and slow injection of rocuronium decreased incidence and severity of RIWM: dilution (RR 0.47, 95% CI 0.39-0.56; SMD -1.64, 95% CI -2.47 to -0.81); slow injection (RR 0.34, 95% CI 0.17-0.70; SMD -2.13, 95% CI -2.74 to -1.51). CONCLUSIONS: The greater part of pharmacological and non-pharmacological interventions showed prophylactic effect against the incidence and severity of RIWM in the Korean population.

The use of 3 sugammadex out of 5 reversal of during recovery of rocuronium-induced neuromuscular blockade in a patient with post-tonsillectomy hemorrhage: a case report / 대한마취과학회지

Post-tonsillectomy hemorrhage (PTH) is the most frequent complication of tonsillectomy, and occasionally results in a lethal outcome. A 21-year-old man (height 180 cm, weight 95 kg) was scheduled for a bilateral tonsillectomy and uvulopalatopharyngoplasty for treatment of obstructive sleep apnea. He required 5 rounds of general anesthesia due to recurrent PTH. The anesthesiologist used sugammadex a total of 3 times to achieve the successful reversal of the deep neuromuscular blockade (NMB) induced by rocuronium. After sugammadex 2 mg/kg was administered, the NMB was reversed in 2 minutes each time. Re-administration of rocuronium within a short time interval after sugammadex may result in unpredictable effects of neuromuscular blocking agents. Sugammadex made it possible to perform a rapid, complete reverse when the residual block was maintained by an incomplete reversal of anticholinesterase.

The effect of hand dominance on neuromuscular monitoring at the adductor pollicis muscle / 대한마취과학회지

BACKGROUND: Neuromuscular blockade of the adductor pollicis muscle may be influenced by hand dominance resulting in conflicting results of several studies. The current study examined whether hand dominance could influence the measurements of neuromuscular blockade with acceleromyography at the adductor pollicis. METHODS: The acceleromyographic responses from 0.6 mg/kg of rocuronium were monitored supramaximally in both hands in 31 patients after induction of anesthesia. Onset, maximum effect, and offset of rocuronium were measured and compared in both hands. The train-of-four (TOF) ratios to 0.9 were recorded in all patients. RESULTS: In total, 27 patients were right-handed and 4 patients were left-handed. The mean supramaximal threshold or initial TOF ratio was not different between dominant and nondominant hands. No statistically significant differences were found between 716 paired TOF ratios in both hands. A correlation was seen between the dominant and nondominant hand (Nondominant = 0.931.Dominant + 1.714, R = 0.929). The analysis by the Bland-Altman plot showed an excellent agreement with a bias of 1.6% and limits of agreement of -21.2 to 24.5%. CONCLUSIONS: Dominant and nondominant hands can be used interchangeably for neuromuscular monitoring at the adductor pollicis.

How should we monitor pediatric patients with Duchenne muscular dystrophy?: A case report / 대한마취과학회지

Duchenne muscular dystrophy is a hereditary disorder characterized by progressive muscle weakness and contracture, and special care during anesthesia is needed in these patients. Because inhalational anesthetics and succinylcholine can cause fatal results, intravenous anesthetics are commonly used. However, monitorings for the pediatric population are not otherwise specified. We report our experience of a 6 year-old boy that underwent muscle biopsy suspicious of muscle dystrophy under general anesthesia. The patient received midazolam, fentanyl, propofol and a small dose of rocuronium. He was monitored with bispectral index (BIS), acceleromyography (TOF). At the end of surgery, recovery of TOF ratio to 90% was evaluated, followed by injection of pyridostigmine and glycopyrrolate. When reversal of neuromuscular block was confirmed quantitatively and clinically, the patient was extubated and he experienced no complication.

Emergence cerebral oxygen desaturation without hemodynamic compromise in pediatric patients / 대한마취과학회지

BACKGROUND: The regional cerebral oxygen saturation (rSO2) decreases significantly during ordinary anesthetic recovery in pediatric patients anesthetized with sevoflurane or desflurane. The present study examined the relationship between rSO2 and the clinical parameters associated with the degree of anesthetic recovery. METHODS: Twelve pediatric patients with American Society of Anesthesiologists physical status 1 were assigned randomly to receive anesthesia with sevoflurane or desflurane. All children underwent general anesthesia for minor surgery. After surgery, the rSO2, the age-adjusted MAC fraction of anesthetic concentration (F(E)), and the bispectral index (BIS) were recorded over a 10-minute period. The correlations between rSO2 and candidate predictors, such as F(E), BIS, anesthetic, and duration of anesthesia, were analyzed. RESULTS: All children recovered uneventfully. The lowest observed rSO2 reached 63% and the maximum decrease in rSO2 was 24%. The mean blood pressure and heart rate were maintained within clinical ranges. The decrease in rSO2 correlated positively with the F(E) (r = 0.25, P = 0.00) and the duration of anesthesia (r = 0.24, P = 0.01), and inversely with the use of sevoflurane (r = -0.30, P = 0.00). CONCLUSIONS: Despite normal parameters, cerebral desaturation occurred during the emergence of ordinary general anesthesia even without hemodynamic compromise or arterial desaturation. Cerebral desaturation might be associated with the degree of anesthetic recovery and the use of sevoflurane.

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.

Effect-site concentration of remifentanil to blunt the hemodynamic changes during rapid sequence intubation

BACKGROUND: This study was undertaken to evaluate the effect-site concentration of remifentanil to blunt the hemodynamic changes during rapid sequence intubation. METHODS: Eighty patients were enrolled and divided into four groups being assigned with different effect-site concentrations (Ce)of remifentanil of 0, 2, 3, or 4 ng/ml. Patients arrived at the operating room without premedication and their baseline vital signs were recorded. With preoxygenation of 100% O2, remifentanil was infused by target controlled infusion according to patient group. After achievement of a stable level of Ce, propofol 2 mg/kg and rocuronium 1.2 mg/kg were injected and the trachea was intubated one minute later. Hemodynamic changes were recorded at 1, 2, and 3 min after remifentanil infusion, immediately before and after endotracheal intubation, and 1 and 2 min after endotracheal intubation. RESULTS: The 50% effective Ce of remifentanil was 1.4 ng/ml (95% confidence interval, CI: 0.9-1.8) to blunt the increase of mean blood pressure and was 2.4 ng/ml (95% CI: 1.6-3.1) to blunt the increase of heart rate. The 50% Ce for the decrease of mean blood pressure was 2.8 ng/ml (95% CI: 2.2-3.4). CONCLUSIONS: During the rapid sequence intubation, the 50% effective effect site concentration of remifentanil to prevent hemodynamic changes is between 2.4 and 2.8 ng/ml.

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.

Response of cerebral oximetry to increase in alveolar concentration of desflurane: effect of remifentanil and cerebrovascular CO2 reactivity / 대한마취과학회지

BACKGROUND: It is known that sympathetic stimulation and increase in cerebral blood flow velocity can be induced by desflurane. Cerebral oxygen balance could be disturbed during desflurane induction. Aim of this study was to elucidate that cerebral oxygen imbalance induced by desflurane mask induction can be reduced by combination of remifentanil and hypocapnia. METHODS: Twenty ASA 1-2 subjects were allocated randomly into 5 groups divided by concentration of remifentanil (0.0, 0.5, 1.0, 1.5, and 2.0 ng/ml). After confirmation of attaining proposed concentration of remifentanil, propofol and vecuronium were administered and mechanical ventilation was done with 8% desflurane with facial mask. Subsequently, changes in regional cerebral oxygen saturation (DeltarSO2), arterial blood pressure, heart rate, cardiac index, estimated alveolar concentration of desflurane (PDESF), and end-tidal concentration of carbon dioxide (PETCO2) were recorded for the following 10 minutes. According to concentration of desflurane and remifentanil, DeltarSO2 and hemodynamic factors were checked. RESULTS: During desflurane induction, changes in cerebral oximetry reached up to +10% (6 [first quartile], 13 [third quartile]). Arterial blood pressure, heart rate, and cardiac index were changed within clinical ranges. The DeltarSO2 showed S-shaped increasing pattern according to increasing PDESF. Hypocapnia and concentration of remifentanil reduced the maximum DeltarSO2 (P = 0.0046, P = 0.0060). Hypocapnia also shifted the curve to left (P = 0.0001). CONCLUSIONS: During 8% desflurane induction, regional cerebral oxygen saturation (rSO2) increases maximum +25%. Hypocapnia and use of remifentanil can reduce the increase in regional cerebral oxygen saturation.

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.

Factors affecting difficult lightwand intubation: a prospective double-blind trial / 대한마취과학회지

BACKGROUND: Unanticipated difficulties during tracheal intubation are related to perioperative morbidity and mortality, but the success of direct laryngoscopic intubation depends largely on clinician's experience and the upper airway anatomy. The lightwand was introduced as alternative intubation technique, but the indicators of difficult lightwand intubation (DLWI) have not been identified. Accordingly authors conducted this study to identify subject factors that affect DLWI, and to compare these with those of difficult laryngoscopic intubation. METHODS: Seventy-three healthy subjects requiring tracheal intubation for elective surgery were enrolled. Anatomic factors, such as, body mass index (BMI), Mallampati classification (MC), inter-incisor gap, thyromental distance, neck circumference, extent of head and neck motion, and Cormack-Lehane grade (CL) were determined and evaluated in terms of their abilities to predict DLWI, which was described using intubation time and number of intubation attempts. Multiple regression analyses were performed to identify predictors using a variable selection technique. RESULTS: Only MC and BMI were found to predict DLWI. The weighted sum of time and number of attempts (r2 = 0.854, P = 0.000) was found to be better predictor of DLWI than their product (r2 = 0.734, P = 0.000). Cormack-Lehane grade was not found to be significantly related to DLWI (P = 0.093). CONCLUSIONS: Of the anatomic factors examined, only Mallampati classification and body mass index were found to predict difficult lightwand intubation.

How much are patients willing to pay for prevention of postoperative nausea and vomiting? / 대한마취과학회지

BACKGROUND: Postoperative nausea and vomiting (PONV) remains a common complication of anesthesia. We tried to assess the amount patients were willing to pay for a hypothetical antiemetic that would completely prevent PONV. METHODS: Trained residents interviewed 86 patients, who were scheduled to undergo general anesthesia, and questionnaires were completed. RESULTS: Patients were willing to pay a median of 30,000 won for an antiemetic that would completely prevent PONV. The amounts patients were willing to pay correlated with age, previous history of PONV, and patient income. CONCLUSIONS: Patients assigned a value for avoidance of PONV. It is suggested that more efforts to prevent PONV would be helpful for the increase in patient satisfaction.

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.

Discrimination of hemoglobin-effects on arterial-to-jugular bulb oxygen content differences according to arterial carbon dioxide tension

BACKGROUND: Arterial jugular bulb oxygen content differences (AJVDO2) can be related to cerebral blood flow and oxygen consumption. Plasma Hb has been reported to have both-sided effect on AJVDO2. Increased Hb increases oxygen content in artery and jugular bulb, and the net effect is to reduce AJVDO2. Moreover, increasing Hb raises blood viscosity, and could increase AJVDO2. This study was designed to discriminate the Hb-effects on AJVDO2 mathematically. METHODS: Sixty adults were enrolled in this study. General anesthesia and mechanical ventilation were administered. A normocapnic and a subsequent hypocapnic state were achieved. Paired data including 1/AJVDO2, PaCO2, Hb, mean arterial pressure, temperature and anesthetic concentration were recorded during each state. Nonlinear mixed-effects model was applied to fit 1/AJVDO2 using PaCO2 and Hb as covariates. RESULTS: The 1/AJVDO2 was well modeled by PaCO2 and Hb using a three-parameter logistic function: predicted 1/AJv DO2 = 0.38713 / 1+e(31.20981-PaCO2)/25.94210-1.45162xHb The increase in PaCO2 raised the 1/AJVDO2 sigmoidally (P < 0.0001) and its slope was affected by Hb (P = 0.0022). The transition point of the Hb-effect was PaCO2 = 31.20981 (SEM 1.519201). Intraclass correlation coefficient was estimated at 0.9973. CONCLUSIONS: Our finding suggests that the Hb-effect on 1/AJVDO2 is both-sided; the viscosity-effect is dominant at low levels of PaCO2 and effect of oxygen content is dominant at high levels of PaCO2

What is an Optimal Effect Site Concentration of Remifentanil for Minimizing the Hemodynamic Change to Endotracheal Intubation using Light Wand? / 대한마취과학회지

BACKGROUND: In the previous studies, remifentanil reduces the hemodynamic change induced by endotracheal intubation. We studied the optimal effect site concentration of remifentanil for endotracheal intubation using light wand. METHODS: Sixty ASA 1 or 2 patients scheduled for elective surgery under general anesthesia were classified in three groups according to the TCI (target controlled infusion) dose of remifentanil. Each group was administered 4microgram/ml of propofol TCI, rocuronium, with 2 ng/ml (group 1), 4 ng/ml (group 2), 6 ng/ml (group 3) of remifentanil TCI. Blood pressure, heart rate and bispectral index score were measured before induction, 3 minutes after remifentanil and propofol TCI, after endotracheal intubation using light wand, and 3 minutes after endotracheal intubation. Statistical analysis was done for comparison of time and dose dependant change among the groups. RESULTS: After endotrachal intubation, blood pressure and heart rate were significantly increased in group 1, and decreased in group 2 and 3. 3 minute after endotracheal intubation, heart rate significantly decreased in group 3, but there were no changes in group 2. CONCLUSIONS: The spontaneous BRS was decreased during ketamine induction of general anesthesia. These results suggest that anesthesia induction with ketamine impairs baroreflex control of heart rate, which may provoke hemodynamic instability.