Seunghyun Chung

Profound bradycardia with lidocaine during anesthesia induction in a silent sick sinus syndrome patient

Sick sinus syndrome is caused by sinus node dysfunction that renders it unable to function as a pacemaker. Patients with sick sinus syndrome are often asymptomatic or have symptoms that are mild and nonspecific. Lidocaine (0.5 mg/kg) injection is used for reduction of pain associated with intravenous injection of propofol. Episodes of marked bradycardia with sinus arrest after prophylactic lidocaine injection are reported in a 69-y-old man with no apparent preoperative cardiac disease or electrocardiographic abnormality. Surgery was postponed, and he was later diagnosed with sick sinus syndrome.

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

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.

Optimal effect-site concentration of remifentanil for preventing development of hypertension during tracheal intubation with inhaled desflurane induction

Background The aim of the present study was to determine the effect-site concentration of remifentanil needed to prevent haemodynamic instability during tracheal intubation with inhaled desflurane induction. Methods One hundred American Society of Anesthesiologists I and II female patients were randomized to receive an effect-site concentration of remifentanil of 0, 1, 2, 3, or 4 ng/ml. Induction of anaesthesia was started with intravenous injection of propofol 2 mg/kg. Ninety seconds after the completion of propofol injection, rocuronium (0.8 mg/kg) and remifentanil were administered simultaneously with 3% desflurane inhalation. Tracheal intubation was attempted 150 sec after the commencement of remifentanil administration. Results A probit model of remifentanil concentration was predictive of successful intubation without development of hypertension (P for goodness-of-fit = 0.419). The effect-site concentration of remifentanil needed to achieve successful intubation without development of hypertension in 95% of the patients was 3.3 ng/ml (95% confidence interval, 2.6-4.8 ng/ml). Conclusions The effect-site concentration of remifentanil of 3.3 ng/ml is effective in blunting the haemodynamic response in 95% of the patients when 2.0 mg/kg of propofol induction was followed by 3% desflurane inhalation.

Emergence cerebral oxygen desaturation without hemodynamic compromise in pediatric patients

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 (FE), and the bispectral index (BIS) were recorded over a 10-minute period. The correlations between rSO2 and candidate predictors, such as FE, 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 FE (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.

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 PETCO2, PETDESF 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 PETDESF. 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.

Characteristics of the similarity index in a Korean medical journal

Background Journal editors have exercised their control over submitted papers having a high similarity index. Despite widespread suspicion of possible plagiarism on a high similarity index, our study focused on the real effect of the similarity index on the value of a scientific paper. Methods This research examined the percent values of the similarity index from 978 submitted (420 published) papers in the Korean Journal of Anesthesiology since 2012. Thus, this study aimed to identify the correlation between the similarity index and the value of a paper. The value of a paper was evaluated in two distinct phases (during a peer-review process vs. after publication), and the value of a published paper was evaluated in two aspects (academic citation vs. social media appearance). Results Yearly mean values of the similarity index ranged from 16% to 19%. There were 254 papers cited at least once and 179 papers appearing at least once in social media. The similarity index affected the acceptance/rejection of a paper in various ways; although the influence was not linear and the cutoff measures were distinctive among the types of papers, both extremes were related to a high rate of rejection. After publication, the similarity index had no effect on academic citation or social media appearance according to the paper. Conclusions The finding suggested that the similarity index no longer had an influence on academic citation or social media appearance according to the paper after publication, while the similarity index affected the acceptance/rejection of a submitted paper. Proofreading and intervention for finalizing the draft by the editors might play a role in achieving uniform quality of the publication.

Optiscope® may have less stimulation on hemodynamic changes.

Ko et al. [1] described that the Optiscope® for tracheal intubation did not reduce the hemodynamic changes, but showed similar hemodynamic changes compared to the laryngoscope. They have named several reasons to back the similar hemodynamic changes with Optiscope® or laryngoscope. One of them is that the irritation by the tube passing through the vocal cords has a larger effect on blood pressure and heart rate than that caused by the Optiscope® or the laryngoscope. Although passing the tube through the vocal cords is a significant stimulation, it may not be as strong as difference on the hemodynamic changes due to intubation methods or devices. If so, previous studies may not have shown the hemodynamic differences with various ways to intubate. We suggest a different approach to explain the hemodynamic changes. The total intensity of the stimulation during laryngoscope is expressed with intensity of its average force and manipulation time [2,3]. Ko et al. described that the median intubation time (interquartile range) was significantly longer in the Optiscope® group, at 20.5 (16.75-28.5) sec, compared to that of the laryngoscope group, at 16.0 (14.75-20.0) sec (P < 0.01). Both groups had similar hemodynamic changes, despite of the longer stimulation time in the Optiscope® group. Therefore, we can say that the intensity of its average force in the Optiscope® group may be lower than in the laryngoscope group, and shortening of manipulation time in the Optiscope® group can reduce the degree of hemodynamic changes. It may be connected to the experience of a performer as Ko et al. have discussed.

Severe back pain following surgery was successfully treated by a lumbar medial branch block − A case report −

Lower back pain commonly develops following spinal anesthesia. This pain is likely caused by strain on the ligaments associated with paraspinous muscle relaxation and positioning during the operation. We describe a case involving a healthy 61-year-old woman with a varicose vein that was scheduled for phlebotomy under spinal anesthesia. Two days after spinal anesthesia, the patient experienced severe lower back pain that was markedly aggravated by twisting and extension of the spine, but subsided with rest. Immediately after a lumbar medial branch block was performed at the area of tenderness the pain subsided. Thease results suggest that immediate treatment of acute lower back pain is important for preventing progression to chronic low back pain.

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

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.