The effect of zirconia surface architecturing technique on the zirconia/veneer interfacial bond strength

PURPOSE: The purpose of this study was to evaluate the effect of the zirconia surface architecturing technique (ZSAT) on the bond strength between veneering porcelain and zirconia ceramic. MATERIALS AND METHODS: 20 sintered zirconia ceramic specimens were used to determine the optimal surface treatment time, and were randomly divided into 4 groups based on treatment times of 0, 1, 2, and 3 hours. After etching with a special solution, the surface was observed under scanning electron microscope, and then the porcelain was veneered for scratch testing. Sixty 3 mol% yttria-stabilized tetragonal zirconia polycrystal ceramic blocks were used for tensile strength testing; 30 of these blocks were surface treated and the rest were not. Statistical analysis was performed using ANOVA, the Tukey post-hoc test, and independent t-test, and the level of significance was set at α=.05. RESULTS: The surface treatment of the zirconia using ZSAT increased the surface roughness, and tensile strength test results showed that the ZSAT group significantly increased the bond strength between zirconia and veneering porcelain compared to the untreated group (36 MPa vs. 30 MPa). Optimal etching time was determined to be 2 hours based on the scratch test results. CONCLUSION: ZSAT increases the surface roughness of zirconia, and this might contribute to the increased interfacial bond strength between zirconia and veneering porcelain.

Comparison of several dosing schedules of intravenous dexmedetomidine in elderly patients under spinal anesthesia

BACKGROUND: Many clinicians have probably used subjective, unscientific methods for dose reduction to avoid overdose in elderly patients. The aim of this study was to compare several dosing schedules of intravenous dexmedetomidine (DEX) to identify the appropriate dosing schedule within the therapeutic dose range for adequate sedation of elderly patients under spinal anesthesia. METHODS: After administration of spinal anesthesia, a loading dose of DEX was injected over 10 min in three groups with the following dosages: group A, 1.0 μg/kg of actual body weight; group B, 1.0 μg/kg of ideal body weight (IBW); and group C, 0.8 μg/kg of IBW. Then, a maintenance infusion (0.5 μg/kg of each BW/h) was administered. The bispectral index score (BIS), the time required to reach BIS 80, airway obstruction score, and the occurrence of bradycardia were recorded. RESULTS: The changes in the BIS among the groups over time were found to have statistically significant differences (P < 0.001). The times required to reach BIS 80 were 6.1 ± 5.3 min, 5.0 ± 3.6 min, and 11.0 ± 8.6 min in groups A, B, and C, respectively (P < 0.001). The airway obstruction score and the frequency of bradycardia did not have statistically significant differences among the groups. CONCLUSIONS: An initial loading dose of DEX that is 0.8 μg/kg of IBW over 10 min, followed by an infusion rate of less than 0.5 μg/kg of IBW/h may be adequate for sedation in elderly patients receiving spinal anesthesia.

Comparison of several dosing schedules of intravenous dexmedetomidine in elderly patients under spinal anesthesia

BACKGROUND: Many clinicians have probably used subjective, unscientific methods for dose reduction to avoid overdose in elderly patients. The aim of this study was to compare several dosing schedules of intravenous dexmedetomidine (DEX) to identify the appropriate dosing schedule within the therapeutic dose range for adequate sedation of elderly patients under spinal anesthesia. METHODS: After administration of spinal anesthesia, a loading dose of DEX was injected over 10 min in three groups with the following dosages: group A, 1.0 μg/kg of actual body weight; group B, 1.0 μg/kg of ideal body weight (IBW); and group C, 0.8 μg/kg of IBW. Then, a maintenance infusion (0.5 μg/kg of each BW/h) was administered. The bispectral index score (BIS), the time required to reach BIS 80, airway obstruction score, and the occurrence of bradycardia were recorded. RESULTS: The changes in the BIS among the groups over time were found to have statistically significant differences (P < 0.001). The times required to reach BIS 80 were 6.1 ± 5.3 min, 5.0 ± 3.6 min, and 11.0 ± 8.6 min in groups A, B, and C, respectively (P < 0.001). The airway obstruction score and the frequency of bradycardia did not have statistically significant differences among the groups. CONCLUSIONS: An initial loading dose of DEX that is 0.8 μg/kg of IBW over 10 min, followed by an infusion rate of less than 0.5 μg/kg of IBW/h may be adequate for sedation in elderly patients receiving spinal anesthesia.

Does preoperative anxiety felt by patients requested to participate in clinical trials related to general anesthesia before elective surgery depend on temperament? / 대한마취과학회지

BACKGROUND: Preoperative anxiety may differ according to patient temperament. It will be increased when patients are requested to participate in a study involving anesthesia. The purpose of this study was to show that the anxiety felt when patients are requested to participate may differ according to temperament in both patients who agree and disagree to participate. METHODS: Three hundred and twenty-one patients over age 18 with American Society of Anesthesiologists 1 and 2 completed a survey questionnaire. The degree of anxiety was measured according to patient temperament. It was compared on the basis of the State-Trait Anxiety Inventory (STAI) and visual analogue scale (VAS). RESULTS: In the agreed group, the degree of anxiety measured by “usual, present STAI” and VAS in the monitors (those who want to know as much as possible about anesthesia and surgery) was significantly higher than that in the blunters (those who want to know as little as possible) (P = 0.041 for the “usual STAI”, 0.017 for “present STAI”, and 0.001 for VAS, respectively). Among patients with a lower educational level, the numbers of blunters and monitors were 57 (79%) and 32 (59%), respectively, indicating that the ratio of blunters was significantly higher (P = 0.026). CONCLUSIONS: Both traits of patients in each group were influenced by psychological burdens. The anxiety of the monitors who agreed to participate was significantly higher than that of blunters. In addition to temperament, education level affects participation. Obtaining consent for participation by understanding temperament and considering factors that may reduce the participation rate will be required.

Development of bilateral tension pneumothorax under anesthesia in a Boerhaave's syndrome patient: a case report / 대한마취과학회지

A 33-year-old male visited the emergency room with abdominal pain which developed after a vomiting episode. Based on the pneumomediastinum findings from a chest radiograph and a contrast-enhanced chest and abdominal computed tomography scan, the patient was diagnosed with Boerhaave's syndrome. Preoperative radiologic findings showed no pneumothorax or pleural effusion. Once anesthesia was administered, the patient developed near complete cardiopulmonary collapse due to a bilateral tension pneumothorax, which was treated by bilateral thoracentesis, followed by chest tube insertion. Despite a left side rupture, the damaged right lung was unable to overcome single right ventilation, so the surgery was completed via right thoracotomy. The ruptured site was treated, and the patient was transferred to the intensive care unit. We discuss the anesthetic implications of this disease and how to prevent fatal complications.

Comparative Study of Unilateral Axillo-Breast Approach with Gas Insufflation Versus Gasless Transaxillary Approach for Endoscopic Thyroidectomy in a Single Institute / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: There have been various approaches introduced for endoscopic thyroidectomy. This study evaluates and compares the surgical outcomes of two such approaches: the unilateral axillo-breast approach (UABA) with gas and the gasless transaxillary approach (TA). SUBJECTS AND METHOD: We retrospectively analyzed 279 patients who underwent endoscopic thyroidectomy via UABA with gas or gasless TA from March 2008 to August 2012. Studied variables were clinicopathologic data, surgical outcomes, complications, and cosmetic satisfactions. RESULTS: Of the 279 patients, 195 (69.9%) underwent UABA with gas and 84 (30.1%) underwent gasless TA. All of the variables related to clinicopathologic characteristics showed no significant differences between the two groups. The mean operation time was significantly shorter in the UABA with gas group (131.76±44.37 min) than in the gasless TA group (191.01±55.90 min) (p<0.001). The mean postoperative pain Visual Analogue Scale scores in the UABA with gas group were 2.61±0.96 and 1.85±0.79, respectively, and those in the gasless TA group were 3.12±1.02 and 2.17±0.76, respectively, at 1 and 3 days after surgery. Incidences of postoperative complications were similar except for the higher rate of seroma in the gasless TA group. Cosmetic satisfaction scores of UABA with gas were higher than those of the gasless TA. CONCLUSION: UABA with gas may be a good option for endoscopic thyroidectomy because this approach is less invasive than the gasless TA is.

Diagnosis and Treatment of Dynamic External Nasal Valve Collapse: Application of Alar Batten Graft and Alar Flaring Suture / 대한이비인후과학회지

In contrast to Caucasians, dynamic collapse of external nasal valve is not a common cause of nasal obstruction in Asians. Nevertheless, Asians with thin skin and weak nasal cartilages can have such problems. To diagnose these patients, visual inspection of external nose during forced inspiration is most important, which physicians frequently neglect. If dynamic collapse is suspected, physicians should locate the maximal site of collapse through modified cottle maneuver. The mainstay of treatment is proper reinforcement of main site of collapse with cartilage graft or various suture techniques. This article presents diagnosis and successful surgical treatments of two cases of dynamic external valve collapse with alar batten graft and alar flaring suture technique.

A Case of Giant Fibrovascular Polyp of the Hypopharynx Removed by Transoral Approach / 대한이비인후과학회지

Giant fibrovascular polyps of the esophagus and hypopharynx are rare, benign, and tumor-like lesions of the upper digestive tract. Due to the initial lack of symptoms, these polyps are often clinically undiagnosed or misdiagnosed until they are significant in size. Most of them can be surgically removed by a cervical incision approach or endoscopic approach. However, we experienced a case of 37 years old male patient, who had a giant fibrovascular polyp of the hypopharynx removed by transoral approach because of the location and size of the stalk. We present this case of a giant fibrovascular polyp of the hypopharynx with a brief review of literature.

Clinical Features and Outcomes of Papillary Thyroid Carcinoma in Patients Aged under 20 / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Thyroid carcinoma rarely occurs in children and adolescents, whose clinical features are diverse, and treatment outcomes are still controversial. The aim of this study was to evaluate the clinical features and the treatment outcomes of papillary thyroid carcinoma (PTC) patients younger than 20 years old. SUBJECTS AND METHOD: This is a retrospective study for patients younger than 20 years old, who were diagnosed as PTC from January 1992 to February 2009. Clinical features, size, pathologic type, extrathyroidal extension, recurrence, multiplicity, extent of surgery, and lymph node metastasis were retrospectively evaluated. RESULTS: Forty patients, of 6 malse and 34 females, were enrolled, with their mean age being 16 years old. The initial operations were total thyroidectomy for 9 patients, unilateral lobectomy for 15 patients, and total thyroidectomy and lateral neck dissection for 16 patients. Cervical lymph node metastases were diagnosed in 25 patients. Extrathyroidal extensions were observed in 30 patients. Postoperative radioactive iodine therapy was performed in 35 patients. During the follow-up period, 8 patients had recurred. All patients were alive at the last follow-up. CONCLUSION: PTC in children and adolescents aged under 20 is a rare disease and tends to present as an advanced disease with low mortality compared to adult PTC. Recurrence had no effect on survival. Aggressive treatment with total thyroidectomy, central neck dissection, and radioiodine therapy may prevent recurrence.

Is there any quality improvement in the randomized controlled trial abstracts in the Korean Journal of Anesthesiology after the publication of the CONSORT abstract guidelines in 2008? / 대한마취과학회지

No abstract available.

The optimal concentration of remifentanil required for i-gel insertion in patients with simulated difficult airways

BACKGROUND: Because difficult airways are not commonly encountered, simulation of a difficult airway using a cervical collar has become a well-established technique of for modeling difficult laryngoscopic views and evaluating interventions for use in difficult airway scenarios. In this study, we have determined the optimal remifentanil concentrations (EC50 and EC95) required for i-gel insertion in anesthetized patients fitted with cervical collars at propofol effect-site concentrations of 4.0 and 6.0 microg/ml (group 4.0 and group 6.0). METHODS: The remifentanil dosage for each propofol effect-site concentration group was determined by the modified Dixon's up-and-down method using previous results. The experiment was started using a 4.0 ng/ml effect-site remifentanil concentration, and the dose was reduced by 0.5 ng/ml for the next attempt when tube insertion was successful; if tube insertion failed, the dose for the next attempt was increased by 0.5 ng/ml. RESULTS: EC50 and EC95 were respectively 2.11 ng/ml (95% CI, 1.78-2.26 ng/ml) and 2.44 ng/ml (95% CI, 2.28-3.67 ng/ml) for the 4.0 group, and 0.42 ng/ml (95% CI, -1.30 to 0.77 ng/ml) and 0.75 ng/ml (0.56-14.3 ng/ml) for the 6.0 group. CONCLUSIONS: In this study, a cervical collar was attached and head fixation was performed to induce a difficult airway. The optimal concentration of remifentanil at a propofol effect-site concentration of 4.0 microg/ml was greater than 2.44 ng/ml (95% CI, 2.28-3.67 ng/ml), and that at the propofol effect-site concentration of 6.0 microg/ml was greater than 0.75 ng/ml (0.56-14.3 ng/ml).

End-tidal concentration of sevoflurane for reducing rocuronium-induced withdrawal reactions in adult patients: a comparison between male and female patients / 대한마취과학회지

BACKGROUND: In this study, we assessed the 50% effective concentration (EC50) of sevoflurane for reducing a rocuronium-induced reaction, based on the Dixon's up-and-down method. We also assessed the 50 and 95% effective end-tidal concentration of sevoflurane (ETsev), based on the probit regression curve of the probability of nonwithdrawal reaction. METHODS: We conducted a prospective, double-blind study in 23 males and 24 females. After using 2.5% thiopental sodium (4 mg/kg), anesthesia was induced in the patients. The patients then inhaled sevoflurane with 5 vol% in 6 L/min of oxygen. When the target ETsev was achieved, a nurse injected the intubating dose of rocuronium (0.6 mg/kg) for 5-10 s under the free flow of intravenous fluid. After the nurse evaluated the response, the nurse recorded the maximum heart rate during 30 s and the mean arterial pressure after rocuronium injection. RESULTS: Based on Dixon's up-and-down method, the EC50 of sevoflurane was 2.5 alpha 0.5 vol% in males and 2.5 alpha 0.3 vol% in females. The probit regression curve of the probability of nonwithdrawal reaction showed that in males the 50% effective ETsev was 2.4 vol% (95% confidence interval [CI], 1.5-3.1 vol%) and the 95% effective ETsev was 3.5 vol% (95% CI, 2.9-11.0 vol%); in females, the 50% effective ETsev was 2.4 vol% (95% CI, 2.1-2.7 vol%) and the 95% effective ETsev was 3.0 vol% (95% CI, 2.7-4.5 vol%). CONCLUSIONS: The inhalation of sevoflurane during the induction period may provide a simple and reliable means of reducing rocuronium-induced reactions without adverse hemodynamic changes. There was no significant difference between males and females.

Massive pleural effusion in ovarian tumor patient during laparoscopic surgery / 대한마취과학회지

No abstract available.

Remifentanil used as adjuvant in general anesthesia for spinal fusion does not exhibit acute opioid tolerance / 대한마취과학회지

BACKGROUND: Although acute tolerance to opioids, especially to remifentanil, has been demonstrated consistently in animal studies, the results of clinical trials in humans are controversial. The aim of this study was to determine whether intraoperative infusions of remifentanil used as an adjuvant in general anesthesia result in acute tolerance, an event manifested by increased postoperative pain and a higher opioid requirement than usual. METHODS: Sixty patients who underwent surgery under general anesthesia for spinal fusion were randomly assigned to receive sevoflurane-nitrous oxide-oxygen (group SO, n = 20), sevoflurane-remifentanil-nitrous oxide-oxygen (group SR, n = 20), or propofol-remifentanil-oxygen (group PR, n = 20) in a double-blinded manner. All patients within 1 hour after induction received PCA (fentanyl 0.4 microg/kg/ml and ondansetron 16 mg) administered intravenously at a basal infusion rate of 1 ml/h, after being intravenously injected with a loading dose of fentanyl (1 microg/kg). Data for fentanyl requirement, verbal Numerical Rating Scale (NRS) pain score at rest, and presence of nausea or vomiting were collected at 1, 24, and 48 hours after surgery. RESULTS: We did not find any significant difference in postoperative PCA fentanyl requirements, NRS or side effects among the groups. CONCLUSIONS: Remifentanil as an adjuvant to sevoflurane or propofol in general anesthesia for adults having surgery for spinal fusion does not appear to cause acute opioid tolerance or hyperalgesia in patients. However, further studies are needed to elucidate whether sevoflurane and propofol exert a clinically significant effect on opioid-induced tolerance or hyperalgesia and whether this effect is related to the age of the patient, the dose and duration of remifentanil given and the intensity of pain experienced postoperatively.

Comparison of the Proseal LMA and intersurgical I-gel during gynecological laparoscopy / 대한마취과학회지

BACKGROUND: The relatively recently developed I-gel (Intersurgical Ltd., Workingham, England) is a supraglottic airway device designed for single-use that, unlike conventional LMAs, does not require an inflatable cuff. In addition, the I-gel, much like the Proseal LMA (PLMA), has a gastric drainage tube associated with an upper tube for decompression of the stomach, thereby avoiding acid reflux and decreasing the risk of pulmonary absorption. The purpose of this study was to compare PLMA and I-gel devices in patients undergoing gynecological laparoscopy based on sealing pressure before and during pneumoperitoneum, insertion time, and gas exchange. METHODS: Following Institutional Review Board approval and written informed consent, 30 adult patients were randomly allocated to one of two groups (the PLMA or I-gel group). In each case, insertion time and number of attempts were recorded. After successful insertion, airway leak pressure was measured. RESULTS: Successful insertion and mechanical ventilation with both supraglottic airway devices was achieved on the first attempt in all 30 patients, and there were no significant differences with respect to insertion time. Likewise, leak pressure did not vary significantly either between or within groups after CO2 insufflation. In addition, differences between leak volume and leak fraction between groups were not significant. CONCLUSIONS: The results of our study indicate that the I-gel is a reasonable alternative to the PLMA for controlled ventilation during laparoscopic gynecologic surgery.

A comparison of the Glidescope(R) to the McGrath(R) videolaryngoscope in patients / 대한마취과학회지

BACKGROUND: The Glidescope(R) videolaryngoscope is a new device for tracheal intubation that provides an improved view of the larynx. This study was performed to compare the Glidescope with the McGrath videolaryngoscope in terms of time to intubation (TTI) and number of attempts. METHODS: Patients were randomly allocated to one of two groups, Glidescope or McGrath group, by using computer-generated numbers. Tracheal intubation was attempted by an anesthesiologist with extensive experience using these two devices. The operator recorded ease of visualization of glottic structures based on the classification described by Cormack and Lehane. Number of failures, number of attempts and their duration, total intubation time, and events during the whole procedure were recorded. The duration of one attempt was defined as the time elapsed between picking up the endotracheal tube and verification of tracheal intubation with visualization of three expiratory carbon dioxide waveforms. TTI was defined as the sum of the duration of all intubation attempts (as many as three), excluding preoxygenation procedures. RESULTS: TTI was significantly shorter for the Glidescope(R) compared to the McGrath(R) laryngoscope (40.5 vs. 53.3 s, respectively, P < 0.05). However, glottic views obtained at intubation were similar between the two groups. Number of intubation attempts was not significantly different between the two groups (1.03 +/- 0.19 vs 1.10 +/- 0.32, respectively) (mean +/- SD). CONCLUSIONS: Study results demonstrated that the Glidescope reduced total intubation time in comparison with the McGrath, in terms of TTI in patients with normal airways.

Ultrasound-guided greater occipital nerve block for patients with occipital headache and short term follow up / 대한마취과학회지

BACKGROUND: The greater occipital nerve (GON) block has been frequently used for different types of headache, but performed with rough estimates of anatomic landmarks. Our study presents the values of the anatomic parameters and estimates the effectiveness of the ultrasound-guided GON blockade. METHODS: The GON was detected using ultrasound technique and distance from external occipital protuberance (EOP) to GON, from GON to occipital artery and depth from skin to GON was measured in volunteers. Patients with occipital headache were divided into two groups (ultrasound-guided block: group S, conventional blind block: group B) and GON block was performed. The same parameters were measured on group S and VAS scores were assessed at pretreatment, 1 week and 4 weeks after treatment on both groups. RESULTS: The GON had distance of 23.1 +/- 3.4 mm (right) and 20.5 +/- 2.8 mm (left) from EOP to GON. Its depth below the skin was 6.8 +/- 1.5 mm (right) and 7.0 +/- 1.3 mm (left). The distance from GON to occipital artery was 1.5 +/- 0.6 mm (right) and 1.2 +/- 0.6 mm (left) in volunteers. Initial VAS score of group S and group B patients were 6.4 +/- 0.2 and 6.5 +/- 0.2. VAS score of 4 weeks after injection were 2.3 +/- 0.2 on group S and 3.8 +/- 0.3 on group B (P = 0.0003). CONCLUSIONS: The parameters measured in this study should be useful for GON block and ultrasound-guided blockade is likely to be a more effective technique than blind blockade in occipital headache treatment.

The general anesthesia experience of deletion 8p syndrome patient: A case report / 대한마취과학회지

A deletion 8p syndrome is a relatively uncommon congenital disease characterized by mental retardation associated with multiple malformation that make anesthetic management a challenge. Anesthetic management of a patient with deletion 8p syndrome may pose a serious problem mainly from difficult tracheal intubation, aspiration complication and cardiac malformation. We experienced a case of 10 year-old boy with a deletion 8p syndrome who underwent appendectomy under the general anesthesia. Intubation was performed by video glidescope after unsuccessful attempt with Macintosh laryngoscope. A high arched palate, short neck, poor patient cooperation due to mental retardation and occasional autistic behaviour made airway management difficult. This case should alert anesthesiologists to the greater difficulties of managing patients with deletion 8p syndrome.

The successful intubation using Shikani Optical Stylet(TM) on difficult intubation patients: A report of 2 cases

The Shikani Optical Stylet(TM) (SOS, Clarus Medical, USA) is another tool to facilitate tracheal intubation. It combines the benefits of a lightwand and a fiberoptic bronchoscope. We report the application of SOS in facilitating the tracheal intubation of two-person with history of difficult airway management. A 25-year-old woman with micrognathia was scheduled to undergo an exploratory laparotomy. Intubation attemps failed with a direct laryngoscope because of difficulty in her mouth opening. Although airway management was re-attempted by a laryngeal mask airway, it also failed for the same reason. Airway management was successfully performed using the SOS instead of a laryngeal mask airway. The second case was a 38-year-old woman with ankylosing spondylitis, scheduled for spinal fusion. She had difficulty in extending her neck. Intubation was successfully performed via the SOS. We believe that intubation by the SOS is a useful and readily available alternative technique for patients with difficult airways.

Ipsilateral Reexpansion Pulmonary Edema Developed after Decortication: A Case Report / 대한구급학회지

Reexpansion pulmonary edema (RPE) is a rare but sometimes fatal complication of the treatment of lung collapse secondary to pneumothorax, pleural effusion, or atelectasis. We experienced a case of RPE that developed following decortication. A 46 year-old female had a decortication for pyothorax under one-lung anesthesia. There was no event during the operation and results of arterial blood gas analysis were within normal limits. After the operation, tracheal extubation was performed and 100% oxygen saturation on a pulse oximeter (SpO2) was maintained with 100% O2, (8 L/min) via mask ventilation with self-respiration. The patient, with 50% Venturi mask, was transported to the intensive care unit (ICU). On arrival at the ICU, a SpO2 of 80% was detected and arterial blood gas analysis revealed hypoxemia with acute hypercapnic respiratory acidosis. Fortunately, reexpansion pulmonary edema was detected early and intensive treatment was performed using mechanical ventilation with positive end-expiratory pressure. Tracheal extubation was performed after 1 day of mechanical ventilation. The reexpansion pulmonary edema was successfully treated and the patient recovered without any complications.