Endotracheal intubation using semi-rigid optical stylet in simulated difficult airways of high grade modified Cormack and Lehane laryngeal views

BACKGROUND: Endotracheal intubation in patients with compromised cervical vertebrae and limited mouth opening is challenging, however, there are still limited options available. Among devices used for managing difficult airways, the Clarus Video System (CVS) might have considerable promise due to its semi-rigid tip. We evaluated the performance of CVS in patients with simulated difficult airways. METHODS: Philadelphia cervical collars were applied to 74 patients undergoing general anesthesia. The degree of simulated difficult airway was assessed by observing laryngeal view using McCoy laryngoscope; modified Cormack and Lehane grade (MCL) ≥ 3a (high-grade group, n = 38) or ≤ 2b (low-grade group, n = 36). Subsequently, patients were intubated using CVS by a blinded practitioner. We evaluated total time to intubation, intubation success rate, and conditions of intubation. RESULTS: Intubation took significantly longer time for the high-grade group than that for the low-grade group (38.2 ± 25.9 seconds vs. 27.9 ± 6.2 seconds, time difference 10.3 seconds, 95% confidence interval: 1.4–19.2 seconds, P < 0.001). However, CVS provided similar high intubation success rates for both groups (97.4% for the high-grade and 100% for the low-grade group). During intubation, visualization of vocal cords and advancement into the glottis for the high-grade group were significantly more difficult than those for the low-grade group. CONCLUSIONS: Although intubation took longer for patients with higher MCL laryngeal view grade, CVS provided high intubation success rate for patients with severely restricted neck motion and mouth opening regardless of its MCL laryngeal view grade.

Recurrent ST segment elevations in a patient with asymptomatic early repolarization during head and neck surgery: implications of vasospastic angina

A 57-year-old woman scheduled for cochlear implant removal exhibited preoperative electrocardiographic findings of early repolarization (ER). Four episodes of transient ST segment elevations during surgery raised suspicion for vasospastic angina (VA). In the post-anesthetic care unit, the patient complained of chest discomfort and received sublingual nitroglycerin with uncertain effect. The patient refused to proceed with postoperative invasive coronary angiography, resulting in inconclusive diagnosis. Intraoperative circumstances limit the diagnosis of VA, which emphasizes the need for further testing to confirm the diagnosis. When VA is suspected in patients with underlying ER, it is reasonable to consider invasive examination to establish the diagnosis and prevent recurrence of VA. If ST changes are observed during surgery in patients with preoperative ER, careful monitoring is recommended. Due to general anesthesia, the absence of patient symptoms limits the definitive diagnosis of those with suspected VA. Therefore, additional postoperative surveillance is recommended.

Pulmonary aspiration during intubation in a high-risk patient: A video clip and clinical implications

We report a case of pulmonary aspiration during induction of general anesthesia in a patient who was status post esophagectomy. Sudden, unexpected aspiration occurred even though the patient had fasted adequately (over 13 hours) and received rapid sequence anesthesia induction. Since during esophagectomy, the lower esophageal sphincter is excised, stomach vagal innervation is lost, and the stomach is flaccid, draining only by gravity, the patient becomes vulnerable to aspiration. As the incidence of perioperative pulmonary aspiration is relatively low, precautions to prevent aspiration tend to be overlooked. We present a video clip showing pulmonary aspiration and discuss the literature concerning the risk of aspiration and its preventive strategies.

Cardiac arrest following reversal of muscle relaxation by pyridostigmine: A case report

The anticholinesterase pyridostigmine is usually used as a reversal agent of non-depolarizing muscle relaxants in general anesthesia. Most adverse muscarinic effects of anticholinesterases are controlled by anticholinergics; however, there is still a potential for fatal cardiac complications. We report a case of cardiac arrest associated with coronary vasospasm that developed during emergence from general anesthesia in a 61-year-old male patient undergoing uvulopalatopharyngoplasty with preoperatively undiagnosed coronary vasospastic angina. Anticholinesterases should be administered with caution for neuromuscular blockade reversal, especially in patients with coronary vasospastic angina.

Cardiovascular collapse due to right heart failure following ethanol sclerotherapy: a case report / 대한마취과학회지

Ethanol sclerotherapy for the treatment of low-flow vascular malformations can cause catastrophic cardiopulmonary complications, including pulmonary embolism and pulmonary hypertension, that can result in right heart failure and fatal arrhythmias, leading to death. We here report a case of abrupt cardiovascular collapse that developed immediately following ethanol sclerotherapy in 31-year-old female patient who had a large arteriovenous malformation in her leg. Anesthesiologists should be aware of the fatal cardiopulmonary complications that are associated with ethanol sclerotherapy and consider the use of invasive hemodynamic monitoring, such as pulmonary artery pressure monitoring, when large doses of ethanol are required.

Comparison of the effects of propofol and pentobarbital on hydrogen peroxide-stimulated hepatic SNU761 cells / 대한마취과학회지

BACKGROUND: Propofol and barbiturates are both known to protect cells of several organs against ischemia/reperfusion injury, but there are few reports on any possible protective effects on human hepatocytes. We investigated the activities of both agents on human hepatic SNU761 cells under hydrogen peroxide (H2O2)-induced oxidative stress. METHODS: To determine whether propofol and pentobarbital protect hepatocytes from H2O2-induced toxicity, we used SNU761 cells, a human hepatocellular carcinoma (HCC) cell line. Cells were pretreated with different dosages (1, 10, 50 micrometer) of propofol or pentobarbital (1, 10, 50, 100, 400 micrometer) 30 min before H2O2 application. Lactate dehydrogenase (LDH) was measured to assess and quantify cell death. To determine the nature of cell death, treated hepatocytes were doubly stained with fluorescein isothiocyanate (FITC)-labeled Annexin V and propidium iodide (PI), and analyzed by flow cytometry. RESULTS: Pretreatment with propofol, but not pentobarbital, suppressed H2O2-induced LDH release. In Annexin V-FITC/PI binding analysis, propofol decreased the number of necrotic and late apoptotic cells, but no significant decreases in such cell numbers were seen when pentobarbital was used. CONCLUSIONS: Unlike pentobarbital, propofol, at clinical concentrations, protected SNU-761 HCC cells against oxidative stress.

The effects of sevoflurane with propofol and remifentanil on tracheal intubation conditions without neuromuscular blocking agents / 대한마취과학회지

BACKGROUND: Propofol and remifentanil are used for tracheal intubation in the absence of neuromuscular blocking agents. We hypothesized that the addition of sevoflurane to propofol and remifentanil would improve intubation conditions and provide hemodynamic stability. METHODS: Seventy-six patients scheduled for elective surgery were randomly allocated to be ventilated with either 4% (group I) or 7% sevoflurane (group II) after propofol injection (2 mg/kg). All patients received remifentanil (1 microgram/kg) 30 seconds after administration of propofol. Ninety seconds after remifentanil was given, laryngoscopy and tracheal intubation were performed. Intubation conditions and hemodynamic changes were evaluated. RESULTS: The overall incidence of clinically acceptable intubation conditions was significantly higher in group II (92%) than group I (58%) (P = 0.001). Scores for vocal cord position, coughing, and limb movement were significantly better in group II (P < 0.05). Mean blood pressure remained significantly lower than the pre-induction level throughout the investigation in both groups (P < 0.001), but there was no incidence of bradycardia or hypotension requiring treatment. CONCLUSIONS: Tracheal intubation without neuromuscular blocking agents can be achieved safely and reliably by adding 7% sevoflurane to propofol (2 mg/kg) and remifentanil (1 microgram/kg).

Effects of propofol and etomidate on hydrogen peroxide-induced oxidative damage in hepatocyte / 대한마취과학회지

BACKGROUND: The present investigation was undertaken to evaluate the protective effect of propofol and etomidate against hydrogen peroxide (H2O2) induced oxidative damage in human hepatic SNU761 cells by measuring lactate dehydrogenase (LDH). METHODS: The cell line of human hepatocellular carcinoma was grown for 24 hours in dissociated cell culture. They were divided into eight groups: negative control (NC) group with no drug administration, positive control (PC) group with H2O2 250 micrometer and other groups pretreated with propofol (P; 1, 10, 50 micrometer) or etomidate (ET; 1, 10, 50 micrometer) followed H2O2 administration. After 7 hours, cell death was assessed by morphology under the light microscope and quantified by measuring the LDH in the culture media. RESULTS: In the light microscopic findings, the intact cells were increased in all three propofol groups compared to group PC. H2O2-induced LDH production was also significantly suppressed in all three propofol groups compared to group PC (P < 0.001). There were no significant differences in the microscopic findings and LDH production between the etomidate groups and group PC. CONCLUSIONS: These results suggest that the propofol has protective effect on the hepatocyte against H2O2-induced oxidative stress.

Effect of propofol and etomidate in respiratory epithelial cell infected with rhinovirus / 대한마취과학회지

BACKGROUND: There have been no previous studies on the effect of anesthetic agents on rhinovirus (RV) infection, which is the most common pathogen of the common cold in human airway epithelial cells. We investigated the effects of propofol and etomidate on the airway epithelial cells infected with RV. METHODS: RV-infected A549 cells were treated with propofol and etomidate for 24 hours. On the third day of infection, cells and supernatant were collected to measure the intercellular adhesion molecule-1 (ICAM-1) expression, viral titer and the amount of cytokine. The extents of the viral replication were expressed as viral titers by 50% tissue culture infection dose (TCID50). RESULTS: The ICAM-1 expression of the groups treated with propofol 1, 10, 100micrometer vs etomidate 1, 5, 25micrometer were 15.6 +/- 4.2, 16.4 +/- 3.7, 14.1 +/- 4.7% vs 16.8 +/- 5.7, 16.4 +/- 5.3, 17.2 +/- 4.5%, but there were not significantly different among subgroups. Productions of cytokines were increased after RV-infection, but there were not significantly different among the propofol and etomidate treated subgroups. The viral titers of the groups treated with propofol and etomidate were not significantly different among subgroups either. CONCLUSIONS: Propofol and etomidate had no effect on the replication of RV and the cytokine release after RV infection in human airway epithelial cells.

Bilateral Pneumothorax Induced by Tracheal Injury during Total Thyroidectomy with Modified Radical Neck Dissection: A case report / 대한마취과학회지

We experienced one case of bilateral pneumothorax developed after total thyroidectomy with modified radical neck dissection in a 44-year-old male patient with thyroid carcinoma. After the conclusion of the operation, the patient was extubated after confirming recovery of consciousness and spontaneous respiration. Soon after the extubation, sudden-onset dyspnea with desaturation was developed. Rapid re-intubation was performed. Bilateral pneumothorax with severe subcutaneous emphysema was recognized on chest radiograph and successfully treated by chest tube insertion. Secondary operation was performed and tracheal injury was proved to be the source of the pneumothorax. The patient was discharged uneventfully 14 days later.

The Effect of Halothane on Hearing Loss and Apoptosis in Noise Exposing Mouse / 대한마취과학회지

BACKGROUND: In large clinical series, noise induced hearing loss (NIHL) following middle ear surgery has been demonstrated in 1.2% to 4.5% of patients and it is associated with a lower incidence than expected. The aim of the present work was to analyze the effect of halothane anesthesia on NIHL and hair cell morphological change. METHODS: We used 40 BALB/c mice with normal Preyer's reflex to investigate the effect of halothane on the NIHL. Control (n = 20) and halothane group (n = 20, respectively) were exposed to 120 dB SPL (sound pressure level), broad band white noise 3 hours daily for 3 consecutive days. The halothane group was anesthetized with halothane while exposed to noise. Hearing thresholds were determined with the auditory brainstem response (ABR). On day 7 post-noise, mice were sacrificed and the cochlea were collected for the histological study. RESULTS: ABR thresholds in the halothane group were less elevated after noise exposure than in the control group and then gradually recovered. In control group, the damage to the outer hair cell and supporting cell was noticeable, but not in halothane group. The expression of Bcl-2 protein was detected in halothane group, the expression of Bax protein was seen in control group. As a result in TUNEL stain, the result is positive in the control group but negative in the halothane group. CONCLUSIONS: The occurrence of NIHL decreased and the tissue damage was suppressed while anesthetized by halothane. And the noise-induced cell death of hair cell was also suppressed during anesthesia.

Protective Effect of Isoflurane on Noise-induced Hearing Loss in Mice / 대한마취과학회지

BACKGROUND: It is well known that the loud noise exposure can lead to noise-induced hearing loss (NIHL). Drilling during mastoid surgery may result in NIHL. The noise level produced by drilling of the mastoid bone can exceed 125 dB HL (hearing level); therefore, mastoid surgery itself is associated with a lower incidence of NIHL than expected. The aim of this study was to analyze the effects of isoflurane on NIHL and hair cell morphological changes. METHODS: BALB/c mice were divided into 2 groups; a control group (n = 20) and an isoflurane group (n = 20). The mice of both groups were exposed to 120 dB SPL (sound pressure level) broadband white noise for 3 hours per day, for 3 consecutive days. The mice in the isoflurane group were anesthetized with isoflurane while exposed to the noise. The auditory brainstem response (ABR) thresholds were determined 1 day before and after the noise-exposure and then again after 7 days. Both cochlea were removed and stained using fluorescent isothiocyanate (FITC) phalloidin. RESULTS: 1 day prior to noise-exposure, the ABR thresholds were those of a normal hearing level in both the control and isoflurane groups. In the control group, the mean hearing threshold was 78.0+/-2.6 dB HL after 1 day of noise-exposure and 81.5+/-3.4 dB HL after 1 week; in the isoflurane group, the mean hearing threshold was 49+/-11.7 dB HL after 1 day and 30.5+/-9.3 dB HL after 1 week. The hearing thresholds after noise exposure in the control were significantly higher than those in the isoflurane group (P<0.05). CONCLUSIONS: The occurrence of NIHL decreased and the hair cell damage suppressed in the mice exposed to intense noise while anesthetized by isoflurane.

Effect of Etomidate on N-methyl-D-aspartate Induced Neurotoxicity in Rat Cortical Neurons / 대한마취과학회지

BACKGROUND: The present investigation was undertaken to evaluate the neuroprotective effect of etomidate against N-methyl-D- aspartate (NMDA) induced neurotoxicity in rat cortical neurons by measuring lactate dehydrogenase (LDH). METHODS: The cerebral cortical neurons of fetal rat were grown for 12 days in dissociated cell culture. They were divided into four groups: first group acted as control with no drug administration and other groups treated with either NMDA 100microM or Etomidate (ET) 10microM + NMDA 100microM or ET 100microM + NMDA 100microM After 24 hrs, cell death was assessed by morphology under the light microscope and quantified by measuring the LDH in the culture media. RESULTS: In the light microscopic findings, the intact cortical neurons were increased in the ET groups. NMDA-induced LDH production also significantly suppressed in ET group (P<0.05). There were no significant difference between the ET 10microM and 100microM groups. CONCLUSIONS: These results suggest that the etomidate has protective effect on the cultured rat cortical neurons against NMDA-induced neurotoxicity.

Patient-controlled Sedation with Propofol and Alfentanil during Colonofiberscopy / 대한마취과학회지

BACKGROUND: The aim of this study was to examine the safety and efficacy of patient-controlled sedation (PCS) according to the lock-out time (LOT, 1 or 2 min) with a demand bolus of propofol and alfentanil fixed during a colonofiberscopy. METHODS: Fifty ASA physical status 1 or 2 patients who underwent a colonofiberscopy were enrolled in this study. They were provided with a PCS pump (Perfusor(R) fm, B Braun Germany, nominal infusion rate, NIR = 1,000 ml/h) containing propofol (9.1 mg/ml) and alfentanil (45.5microgram/ml) in order to self-administer a 2 ml bolus whenever they felt uncomfortable. The lock-out time (LOT) was set to 1 (n = 20, group 1) or 2 (n = 30, group 2) minutes. The Observer's Alertness/Sedation (OAA/S) score, D/A (delivery/attempt, %), blood pressure, heart rate, respiratory rate, SpO2, end tidal CO2 and bispectral index (BIS) were assessed and measured during and/or after the procedures. The verbal descriptive pain scores, as well as the patient's and endoscopist's satisfaction scale were assessed after the procedures. RESULTS: Intraoperative and postoperative pain scores, D/A, the patient's and endoscopist's satisfaction were similar in both groups. However, the lowest BIS values in group 1 was lower than in group 2 (70.3 +/- 12.2 and 77.6 +/- 6.8, respectively, P = 0.010). There were fewer patients whose lowest OAA/S score was <3 in group 2 (4/30) than in group 1 (11/20)(P = 0.002). CONCLUSIONS: With a demand bolus of propofol (18.2 mg) and alfentanil (91.0microgram) fixed, the incidence of over-sedation was higher at LOT 1 min than at LOT 2 min while the efficacy was similar in the PCS with a high NIR during the colonofiberscopy.

The Effects of Dexmedetomidine on Hemodynamics and Plasma Catecholamine Concentrations during Coronary Artery Bypass Graft Surgery / 대한마취과학회지

BACKGROUND: Alpha-2 adrenergic agonists decrease the sympathetic tones of hemodynamic and endocrine responses to surgical stimuli. The goal of this study was to evaluate the hemodynamic and endocrinologic effects of intraoperatively administered dexmedetomidine, a highly selective alpha-2 adrenergic agonist, in patients undergoing coronary artery bypass graft surgery. METHODS: Fifty coronary artery bypass graft patients, in a double-blind, randomized manner, received a continuous infusion of normal saline placebo or dexmedetomidine, 10 ng/kg/min for 1 hr from 5 minutes after sternotomy. All patients received standardized anesthesia. Plasma catecholamine was measured at 5 minutes after sternotomy (T1), 30 minutes after drug infusion (T2), and 30 minutes after drug cessation (T3). Heart rate, blood pressure, pulmonary artery pressure and cardiac output were monitored. RESULTS: Compared with the placebo group, plasma norepinephrine concentrations decreased in the dexmedetomidine group Dexmedetomidine attenuated increased blood pressure on surgical stimuli and induced more hypotension. CONCLUSIONS: The intraoperative infusion of dexmedetomidine to patients undergoing coronary artery bypass graft surgery reduced sympathetic tone and attenuated hemodynamic responses to surgical stimuli.

Effect of Etomidate on the Expressions of c-JUN and Heat Shock Protein 70 Induced by Kainic Acid in Rats / 대한마취과학회지

BACKGROUND: The present investigation was undertaken to evaluate the neuroprotective effect of etomidate against kainic acid (KA) induced neurotoxicity in rats by Western immunoblotting for heat shock protein 70 (HSP-70), c-JUN, and by acid-fuchsin histochemistry. METHODS: Etomidate (20 mg/kg, i.p.) was administered in sequence, first being just one hour after KA (10 mg/kg, i.p.) injection, then three times one hour intervals. Neuronal damage in hippocampus was evaluated by using acid-fuchsin stain to detect cell death and HSP-70 and c-JUN induction as an index of cell injury at 3, 6, 24 and 48 h after the administration of KA. RESULTS: Acid fuchsin positive neurons were increased in the CA1 and CA3 regions of the hippocampus after KA injection, but were significantly decreased by etomidate injection (P <0.01). Etomidate administration also significantly suppressed the KA-induced induction of c-JUN and HSP-70 in both regions of the rat hippocampus. CONCLUSIONS: These results suggest that etomidate has a protective effect on hippocampal neurons against KA-induced neurotoxicity.

Changes of Blood Pressure and Heart Rate According to the Effect-Site Concentrations of Alfentanil during Endotracheal Intubation with the Effect-Site Concentration of Propofol Fixed at 4microgram/ml / 대한마취과학회지

BACKGROUND: Propofol and alfentanil are frequently combined for general anesthesia. The purpose of this study was to characterize the appropriate effect-site concentration of alfentanil combined with an effect-site concentration of propofol of 4 microgram /ml during endotracheal intubation. METHODS: One hundred and thirty patients, aged 40-70 years and scheduled for abdominal surgery were randomly allocated to four groups according to the target effect-site concentrations of alfentanil: 0 ng/ml in the placebo group, 50 ng/ml in the P50 group, 75 ng/ml in the P75 group, and 100 ng/ml in the P100 group. All patients received a computer controlled infusion of propofol with an effect-site concentration of 4microgram/ml. After equilibration between plasma and effect-site was achieved, and the trachea of the patient was intubated. The assessments of hemodynamic changes were usually confined to the measurement of changes in systolic/diastolic blood pressure (SBP/DBP), mean arterial pressure (MAP), and heart rate (HR). Also, we checked the dose requirements of ephedrine and atropine used to correct hypotension and bradycardia. RESULTS: The use of alfentanil (especially 50 or 75 ng/ml) was effective at blunting the SBP increase during the few minutes after intubation. However, the dose requirements of ephedrine and atropine in the P100 group were significantly higher than those in other groups. CONCLUSIONS: The appropriate effect-site concentration of alfentanil combined with an effect-site concentration of propofol of 4microgram/ml during endotracheal intubation lies between 50 and 75 ng/ml.

The Comparison of the Concentration of Free Hemoglobin in Packed RBC, Intraoperative Salvaged Blood and CPB Residual Blood during Cardiac Surgery / 대한마취과학회지

BACKGROUND: Intraoperative autotransfusion or residual blood in a cardiopulmonary bypass (CPB) circuit has been used to reduce the need for an homologous blood transfusion during cardiac surgery. However, it may contain some free hemoglobin released from damaged cells. The load of blood containing free hemoglobin may cause renal dysfunction. We measured the amount of free hemoglobin in banked blood, cell saver blood and CPB blood to evaluate what is the least hemolytic blood transfused in cardiac surgery. METHODS: This study was performed in 20 patients undergoing cardiac surgery. In each patient, the banked blood, intraoperative salvaged blood with a cell saver and CPB residual blood were sampled at the end of the operation. The concentration of free hemoglobin, hemoglobin and platelet counts were measured in these blood samples and percent of hemolysis was calculated (%hemolysis = [free hemoglobin] / [free hemoglobin hemoglobin]) RESULTS: In salvaged blood with a cell saver, CPB residual blood and banked blood, hemoglobin concentrations were 20.1+/-2.7 g/dl, 8.0+/-1.1 g/dl, and 22.2+/-2.7 g/dl, respectively. Free hemoglobin concentrations were 336.6+/-239.5 mg/dl, 49.2+/-26.8 mg/dl, and 279.5+/-167.5 mg/dl respectively. Platelet counts were 26.1+/-22.2X10(3)/mm3, 116.8+/-56.5X10(3)/mm3, and 94.9+/-43.6X10(3)/mm3 respectively. % Hemolysis were 1.6+/-1.1%, 0.6+/-0.4%, and 1.2+/-0.7% respectively. In the comparison between the salvaged blood with a cell saver and CPB residual blood, free hemoglobin concentration, % hemolysis, and platelet counts had positive correlations (r = 0.8, 0.7, and 0.6). CONCLUSIONS: In twenty cardiac surgeries, CPB residual blood had a lower free hemoglobin level than the other two blood groups. The platelet counts in CPB residual blood were higher than those in cell saver blood but did not differ from those in banked blood. Therefore, CPB residual blood was the least hemolytic blood among the three blood groups when a transfusion was performed in cardiac surgery.

Effects of Etomidate and Propofol on the Calcium Current in the Rat Myocytes / 대한마취과학회지

BACKGROUND: Cardiovascular instability after induction of intravenous anesthetics may be explained partly by direct negative inotropic effects. We studied the effects of etomidate and propofol on the inward calcium currents (ICa) of rat ventricular myocytes using the whole-cell voltage-clamp technique. METHODS: ICa was elicited by progressively depolarizing cells from -40 to -50 mV. The peak amplitude of ICa was measured before, during and after the administration of equimolar concentrations of etomidate and propofol. RESULTS: Exposure to etomidate and propofol produced a concentration-dependent inhibition of ICa.; 1, 10, 100 and 300 micrometer of etomidate decreased the peak ICa (mean +/- SEM) by 14.5 +/- 6.3, 25.9 +/- 9.4, 31.9 +/- 12.1, 42.5 +/- 8.8% and 1, 10, 100 and 300 micrometer of propofol decreased the peak ICa by 15.7 +/-3.4, 21.3 +/-2.5, 59.2 +/-2.0, 69.9 +/-2.8%, respectively. COCLUSIONS: These results suggest that etomidate and propofol have a direct negative inotropic effect via inhibition of inward calcium currents in rat ventricular myocytes.