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Background: Postoperative nausea and vomiting (PONV) is a common problem in patients undergoing thyroidectomy. In this study we evaluated the effects of prophylactic dolasetron and/or induction with propofol on PONV. Methods: Two hundred three patients scheduled thyroidectomy under general anesthesia with sevoflurane were included and were randomly allocated to one of four groups. In control (group C) and dolasetron groups (group D), the patients received thiopental sodium 4−5 mg/kg intravenously for the induction of anesthesia, and the patients in group D received prophylactic intravenous dolasetron 210 μg/kg. In propofol (group P) and dolasetron ＋ propofol groups (group D ＋ P), the patients received propofol 2 mg/kg intravenously for the induction of anesthesia, and the patients in group D ＋ P received prophylactic intravenous dolasetron 210 μg/kg. The incidence and severity of PONV, the need for rescue antiemetics, adverse events were assessed during 0 to 1 hour and 1 to 24 hours postoperatively. Results: During the first 24 hours after anesthesia, the incidences of PONV and postoperative vomiting were significantly reduced in group D ＋ P compared with group C (P ＜ 0.05, respectively). There were no significant differences in postoperative nausea, need for rescue antiemetics, severity of PONV, and adverse events of antiemetics among the four groups. Conclusions: In patients with thyroidectomy, combination of prophylactic dolasetron administration and induction with propofol was found to reduce the incidence of PONV during the first 24 hours after anesthesia, compared with that of routine induction with thiopental sodium. (Korean J Anesthesiol 2009; 57: 320∼6)

Transurethral resection of the prostate is the gold standard in the operative management of benign prostatic hyperplasia. Bipolar transurethral resection of the prostate using saline solution is a safe technique and reduces the risk of transurethral resection syndrome. This report discusses a rare complication of bipolar transurethral resection of the prostate: the extravasation of 0.9% saline solution into intraperitoneal and retroperitoneal cavities due to bladder perforation, resulting in respiratory difficulties. (Korean J Anesthesiol 2013; 65: 163-166)

Malignant hyperthermia (MH) may lead to metabolic crisis of skeletal muscle in susceptible individuals following exposure to triggering agents such as volatile anesthetics or depolarizing muscle relaxants. MH is a rare and a potentially lethal disease, which can lead to cardiac arrest. We report a case of severe MH, in which the rapidly evolving signs of hypermetabolism eventually resulted in cardiac arrest. Despite conventional treatments following cardiopulmonary resuscitation, the patient's vital signs did not improve. Therefore, we applied extracorporeal membrane oxygenation for providing hemodynamic support.

Background This randomized single-blinded, cross-over study was done to evaluate the influence of the size of tracheal tubes on air leaks around the cuffs. Methods In a benchtop model, the number of longitudinal folds on the cuffs was evaluated for different sizes of tracheal tubes. In an anesthetized patient study, thirty patients scheduled for elective surgery under general anesthesia were included. After induction of anesthesia, the trachea was intubated with two sizes of tracheal tubes in a random sequence: in men, internal diameter of 7.5 mm and 8.0 mm; in women, internal diameter of 7.0 mm and 7.5 mm. After tracheal intubation with each tube, air leak pressures were evaluated at intracuff pressures of 20, 25 and 30 cmH(2)O by auscultation. To calculate the tracheal tube resistance (R), an inspiratory pause of 20% was applied and the resulting peak airway pressure (P(peak)), plateau pressure (P(pl)) and mean expiratory tidal volume (Flow) were inserted in the formula R = (P(peak) - P(pl))/Flow. Results More longitudinal folds of the tracheal tube cuffs occurred in larger sized tubes compared to the smaller ones in a benchtop model. Air leakage was significantly less for the smaller tracheal tubes than for the larger ones for each gender at intracuff pressures of 20, 25 and 30 cmH(2)O. Tracheal tube resistances were not significantly altered by the size of tracheal tube. Conclusions The use of a smaller tracheal tube within an acceptable size can reduce air leakage around the cuff without significantly changing the tracheal tube resistance.

Background The aim of this retrospective study was to compare the clinical performance of the modified Marsh model for propofol between underweight and normal-weight patients with Crohn's disease. Methods The medical records of 50 patients who underwent elective surgery for Crohn's disease were reviewed retrospectively. Propofol and remifentanil were administered using target effect-site concentration (Ce)-controlled infusion with the modified Marsh and Minto models. Target Ce values of propofol were adjusted within a range of 2.5–3 µg/ml to maintain a bispectral index (BIS) value of less than 60 during anesthesia maintenance. Dosages of anesthetic agents administered during surgery were compared between underweight and normal-weight patients. The infusion profiles of patients were applied as inputs to calculate the Ce values in the Schnider model. Results The total midazolam and remifentanil dosages required for underweight patients were higher than those required for normal-weight patients to maintain BIS values at less than 60 within a target propofol Ce range of 2.5–3 µg/ml. Simulation results suggested that the Schnider model may be an appropriate pharmacokinetic model for target-controlled infusion in underweight patients, as the clearance was consistently higher in the Schnider model than the modified Marsh model, particularly in underweight patients. Conclusions The modified Marsh model might cause inadvertent propofol underdosing in underweight patients. Future studies are necessary to compare the predictive performance of the modified Marsh and Schnider pharmacokinetic models in underweight patients.

Intraoperative transesophageal echocardiography (TEE) has become an important monitoring device for patients undergoing cardiac or noncardiac surgery. Complications associated with TEE are unusual, but the potential for TEE probe compression of the posterior vascular structures has been reported in pediatric patients. We present here a case of occlusion of the right subclavian artery in an adult patient with a vascular ring after insertion of a TEE probe.

Corticosteroid injection is frequently used for the control of inflammation of the joint, tendon, and ligament. Compared to systemic corticosteroid injection, the incidence of complications after local corticosteroid injection is extremely low with an estimated risk of less than 1% [1]. A previously 46-year-old woman, who had a splint for approximately one month due to right wrist pain caused by a car accident in April 2012, visited an orthopaedic clinic due to continuing pain after one month. A corticosteroid was injected (triamcinolone acetonide 20 mg) into the transverse carpal ligament once. The patient had numbness for 2 days after injection, and had pain, hypopigmentation, muscle atrophy one month after the corticosteroid injection (Fig. 1A). The patient visited our pain clinic in September 2012. She had pain of visual analogue scale (VAS) 2 in the medial region of the right wrist in the resting state, and had increased pain of VAS 4-5 during contact on the right wrist or wrist motion. No sensory deficit or hyperalgesia was observed in the right wrist. Fig. 1 (A) Hypopigmentation and subcutaneous atrophy and muscle atrophy in the wrist after local corticosteroid injection. (B) Resolved symptoms in the wrist at one year after local corticosteroid injection. As she was suspected to have nerve injury due to corticosteroid injection, she underwent three phase bone scan, electromyography, and the nerve conduction test. The results showed normal findings. Her muscle atrophy was severe. Accordingly, the patient underwent electromyography and the nerve conduction test specifically on the atrophied muscle after discussion with the department of rehabilitation and the department of neurology. As a result, nerve injury was observed in the focal deep branch of the ulnar nerve that governs the opponens digiti minimi muscle. Gabapentin (Neurontin®, Pfizer Inc., New York, NY, USA) 100 mg, tramadol 37.5 mg/acetaminophen 325 mg 1 tablet, and clonazepam 0.5 mg 0.5 tablet were administered to the patient twice a day. After drug administration, pain was reduced, but discomfort persisted during contact. Thus, she was referred to the department of plastic surgery for autologous fat injection. Approximately one year after the onset of her symptom, she visited our clinic and showed spontaneous recovery of hypopigmentation and fat and muscle atrophy and decrease in pain to VAS 0-1 during contact (Fig. 1B). Thus, we decided to observe residual symptom without any procedure. Local corticosteroid injection has complications such as infection, sepsis, facial flushing, hypopigmentation, perilymphatic atrophy, bleeding, tendon rupture, steroid flare, soft tissue atrophy, and hypersensitivity reaction. In this case study, the patient had hypopigmentation, subcutaneous fat and muscle atrophy, and nerve injury. Skin hypopigmentation has been reported to occur in 1.3-4% of patients who underwent local corticosteroid injection [2]. Although the exact mechanism of hypopigmentation is unclear, steroids or biologically inactive components of steroids have been known to be involved in hypopigmentation [3]. In addition, dermal complications after corticosteroid injection are also explained by mechanical effects caused by edema, changes in ground substances, or vasoconstriction. Hypopigmentation occurs 1-4 months after corticosteroid injection, and then resolves 6-30 months after the injection. However, it can be prevented if intradermal and subcutaneous injections are avoided [4]. Subcutaneous fat atrophy and hypopigmentation may occur by injection of any type of steroid into the soft tissue. However, if steroids with suitable solubility and potency are used, the risk of subcutaneous fat atrophy and hypopigmentation can be reduced. Therefore, steroids with low solubility, such as triamcinolone acetonide, are preferably injected into the joint of deep structures such as the knee, elbow, and shoulder, whereas steroids with high solubility, such as betamethasone sodium and dexamethasone, are preferably injected into soft tissues such as the bursa, tendon sheath, metacarpophalangeal joint, proximal phalangeal joint, and carpal tunnel. Steroids cause fewer complications if their efficacy duration is shorter. In addition, for the prevention of subcutaneous fat atrophy, compressing the injection site with gauze is recommended after pulling out the needle to prevent steroid leakage along the needle track [1]. Subcutaneous fat atrophy has been known to last for 6-12 months after corticosteroid injection, and it is known to be reversible and resolved within one year. If subcutaneous fat atrophy lasts for more than one year, surgical treatments such as fat graft and fat injection can be considered [5]. Thus, in the present case study, the necessity of surgical treatment was explained to the patient, followed by treatment under collaboration with the department of plastic surgery. Few studies have been conducted to investigate the incidence of nerve injury after corticosteroid injection. Via microneuronal circulation studies and histological studies, steroids were reported to have neurotoxicity. Injection site is one of the important factors in the occurrence of nerve injury. In particular, intrafacicular injection causes nerve injury. Besides, the severity of nerve injury may vary depending on the drug used. Hydrocortisone and triancinolone acetonide cause more extensive axon and myelin degeneration compared to dexamethasone. Muscle atrophy mainly occurs during systemic corticosteroid injection. However, its frequency or prognosis is unclear. In this case, muscular atrophy after local steroid injection occurred and resolved. Studies about the mechanism and cause of muscular atrophy will be required in the future. In conclusion, although subcutaneous fat atrophy, depigmentation, nerve injury and muscular atrophy after local corticosteroid injection are rare, physicians should be aware of potential adverse side effects. It is reported in the majority of cases that these side effects are generally resolved in 6 to 30 months. In the case discussed here, when a complication occurs, the physician can explain to the patients that close observation is demanded up to one year after local corticosteroid injection. The surgical option (ex. fat injection) can be considered when the symptom persists over year after local corticocteroid injection.

In 1970, Swan et al. [1] reported that a pulmonary capillary wedge pressure could be obtained by cardiac catheterization without the aid of fluoroscopy. Since then, the Swan-Ganz pulmonary artery catheter has been widely used to monitor hemodynamic changes and cardiac output in critically ill patients. A pulmonary artery catheter is placed through a large-bore introducer sheath and the right internal vein is preferred because of its straight course to the right atrium and right ventricle. Recently, we encountered a patient, in whom entrapment of the pulmonary artery catheter occurred as it entered the right ventricle, leading to catheter function failure. The patient required surgical removal of the catheter. A 66-year-old male was admitted for a transient ischemic attack. The patient had a history of hypertension and type II diabetes mellitus. The brain MRI/MRA revealed a total occlusion of the right proximal internal carotid artery, severe stenosis in the right proximal external carotid artery, and an atheromatous plaque with moderate narrowing of the left proximal internal carotid artery. To evaluate the cerebral vessels, a transfemoral cerebral angiography (TFCA) was performed. The patient had a mild stenotic artery with an ulcer in the left internal carotid artery. He was scheduled for a left carotid endarterectomy. To evaluate his heart function before surgery, a myocardial single-photon emission computed tomography was performed. A perfusion decrease in the basal anterior wall was found. A coronary angiography confirmed diffuse three vessel disease. After consultation between neurosurgery and cardiothoracic surgery, the patient was scheduled to undergo a simultaneous carotid endarterectomy and coronary artery bypass graft surgery. Before the induction of general anesthesia, the continuous arterial pressure was monitored by placing a 20-guaged catheter in the right radial artery. An induction was done using 5 mg of midazolam, 6 mg of etomidate, and 10 mg of vecuronium. After endotracheal intubation, an advanced venous access (AVA) catheter was placed in the right internal jugular vein under ultrasound guidance. Afterwards, the Swan-Ganz catheter (SGC) was inserted with the catheter tip facing the 9 o'clock direction. The catheter advanced smoothly up to 70 cm, but failed to reach the pulmonary artery and could not be advanced further. In the subsequent attempt, the catheter was inserted to 70 cm, but it was also unsuccessful. Resistance was felt when trying to withdraw the catheter for a third insertion attempt. The catheter withdrawal was immediately stopped, and a chest radiograph was performed and checked in the operating room. The chest radiograph showed an acute angulation of the SGC at the tip of the AVA catheter. Radiology consultation confirmed that the tip of the SGC was in the left azygous vein. There was no arrhythmia and the arterial pressure was stable throughout the insertion-withdrawal-reinsertion procedure. Following a successful carotid endarterectomy, the cardiac surgeon began coronary artery bypass graft surgery. After initiating a cardiopulmonary bypass, the SGC was retrieved. There was a small notch at the 40 cm mark of the catheter, but no evidence of knotting (Fig. 1). Fig. 1 Chest X-ray after pulmonary artery catheter placement and the retrieved pulmonary artery catheter. The chest X-ray shows an acute angle bending of the pulmonary catheter. The picture in the left lower corner shows the retrieved pulmonary artery catheter ... Several complications are associated with the insertion and presence of a SGC. A previous report showed that among 230 SGCs inserted, 9 (3.9%) were associated with major complications including a knotted catheter that had to be surgically removed [2]. Other reported complications include severe dysrhythmias (ventricular tachycardia or fibrillation) (0.3-62.7%), a small increase in tricuspid regurgitation (17%), a right bundle-branch block (0.1-4.3%), and complete heart block in patients with prior left bundle-branch block (0-8.5%). Complications related to the catheter itself include pulmonary artery rupture (0.03-1.5%), catheter related infections (1.4-34.8%), catheter-related sepsis (0.7-11.4%), thrombophlebitis (6.5%), venous thrombosis (0.5-66.7%), pulmonary infarction (0.1-5%), mural thrombus (28-61%), valvular or endocardial vegetations or endocarditis (2.2-100%), and even death (0.02-1.5%) [3]. In our case, the anteroposterior chest radiograph suggested that the SGC was knotted. The catheter, however, turned out to be just trapped. Benson and Patla [4] suggested that the distinction could be made by sliding the introducer sheath over the catheter and continuing to withdraw the sheath and catheter from the patient. If the catheter still is trapped, it is most likely caught somewhere in the heart or the great vessels. We suspect that the reason for the catheter's entrapment was due to the twisting force applied to the catheter for insertion into the pulmonary artery. The thermodilution section of the wire is stiffer than other parts of the SGC, and during withdrawal of the SGC, the area just above the thermodilutional wire was bent (Fig. 1). Surgical procedures are usually performed for the removal of large sized knots and loops, intracardiac fixing of the SGC, and suture entrapments of the SGC. Depending on the entrapped site, subclavian venotomy, jugular venotomy, femoral venotomy, or cardiotomy can be done. Even though this case was different from the above mentioned cirucumstances, a sternotomy and cardiopulmonary bypass was electively done for the coronary bypass graft operation and the cardiac surgeon performed an atriotomy and removed the catheter. Nonsurgical removals have resolved many knots and loop problems for more than 30 years by radiologists. Interventional radiologic techniques have been invented to untie knotted catheters and to retrieve embolized catheter fragments. With the internal jugular vein approach, the deflection wire can be used. The wire is locked in the first turn of the SGC and the catheter is then withdrawn and the folded part of the catheter slipping over the wire is released [5].

Central venous catheterization by Seldinger's technique uses a guidewire which may cause complications such as kinking, knotting and fracture. Fractured guidewire may lead to severe outcomes such as embolization, and removal of it may also cause problems such as vessel damage. We experienced a case of right internal jugular venous catheterization complicated by guidewire fracture entrapped in the central venous catheter, and its successful removal under fluoroscopic guidance using snare­loop. The patient recovered without any complications. When resistance is felt during insertion or withdrawal of the guidewire, force should not be applied to the guidewire and care should also be exercised when passing the tissue dilator over the guidewire. Clinicians should be aware of this rare complication and snare­loop technique could be considered as one of the methods for removal of the fractured guidewire. (Korean J Anesthesiol 2012; 63: 457­460)

BACKGROUND The plasma effect-site equilibrium rate constant (k(e0)) of propofol has been reported in various pharmacodynamic studies; however, it is not desirable to apply k(e0) for the link with pharmacokinetic models that were separately investigated. Thus, we titrated k(e0) for the pharmacokinetic model, which is known as the multiple covariates adjusted model of propofol. METHODS Ninety female patients scheduled for gynecologic surgery were randomly assigned to three groups targeting different plasma concentrations of 5.4, 8.1, and 10.8 microg/ml. Target-controlled infusions (TCI) were provided by a computer-assisted continuous infusion system. Time to loss of responsiveness (LOR) was measured by a blind investigator; effect-site concentrations (C(e)) for LOR were then calculated with simulation of TCI using different k(e0)s. We determined the k(e0) minimizing total discrepancy (TD) between the inputted and calculated k(e0) from the t(1/2)k(e0)s for a given probability of LOR of the C(e), and also obtained the k(e0) for the minimal TD between the median C(e), which were compared to the known k(e0). RESULTS K(e0)s from these two methods were 0.3692 and 0.3788/min. C(e)s for LOR with these k(e0)s were significantly different from those with Schnider's k(e0). CONCLUSIONS We proposed a method for titration of the k(e0) of propofol. The k(e0)s of propofol was lower than Schnider's k(e0). An adequate k(e0) for the specific pharmacokinetic model and a certain population would be useful for prediction of an accurate C(e), and could be used for calculation of accurate dosing during targeting of the effect site.

Background: To know whether the laryngeal mask airway (LMA) triggers a pharyngo-esophagogastric reflex during general anesthesia, we compared the esophageal motility of patients with an LMA or endotracheal tube (ETT) in place. Methods: Fifty patients (ASA I or II) scheduled for elective orthopedic surgery with general anesthesia were randomly allocated into LMA (n = 30) or ETT (n = 20) groups. The esophageal manometric inputs were recorded continuously using an ambulatory esophageal manometric recorder and divided into five perioperative phases (preanaesthesia, induction, operation, LMA or ETT rejection, and arousal phase). Results: The peristaltic percent and number of contractions per minute were significantly decreased during induction, operation, LMA or ETT rejection and arousal phases compared with preanesthetic phases in both the LMA and ETT groups. However, there were no significant group differences in any corresponding perioperative phases. Conclusions: We suggest that during general anesthesia the use of a LMA does not provoke significantly different esophageal peristalsis compared with an ETT. Thus, the LMA is unlikely to potentiate gastric regurgitation and reflux during general anesthesia by stimulating the pharyngo-esophago-gastric reflex.