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Biomedical subjects

C S Sung

Publications and source records attributed to C S Sung.

15 recordsLinked to original sources

Abdominal vascular injury during lumbar disc surgery.

Major vascular injury is an unusual but well-recognized complication of vertebral disc surgery. Isolated arterial laceration is the most common type of this vessel injury in lumbar spine surgery, with early manifestation due to retroperitoneal hemorrhage. Two cases are described that illustrate the full spectrum of acute manifestation of such injuries. Two cases of acute hemorrhage due to arterial trauma were seen; one mortality case was recognized during the operation and one salvaged in the recovery room. In both cases unstable perioperative hemodynamics and postoperative distended abdomen were observed. It is the purpose of this paper to report two cases and to discuss the morbid anatomy, diagnosis of such vascular injuries and anesthetic handling of retroperitoneal hemorrhage. For anesthesiologists who are also drill workers while doing lumbar spinal or epidural anesthesia, these rare catastrophes remind us to pay special attention to the vertebral vascular (not only skeletal) anatomy.

Abdomen↗

Effect of oral clonidine premedication on perioperative hemodynamic response and postoperative analgesic requirement for patients undergoing laparoscopic cholecystectomy.

BACKGROUND: To investigate the clinical efficacy of oral clonidine premedication in anesthesia and analgesia in patients undergoing laparoscopic cholecystectomy (LC). METHODS: One hundred and ten patients, scheduled for elective laparoscopic cholecystectomy, were recruited for the prospective, randomized, single-blind, comparative study. They were randomly allotted to either of the placebo or clonidine group. Patients of the placebo group (n = 65) were premedicated with oral antacid (alugel hydroxide 300 mg), while those in the clonidine group (n = 45) were premedicated with oral clonidine 150 micrograms prior to anesthesia. The premedication was given 60 to 90 min before the anticipated time of induction of anesthesia. Normocapnia was maintained throughout the perioperative period. Mass spectrometer was used to assess the inspired and expiratory concentrations of isoflurane, the anesthetic used for maintenance of anesthesia. Postoperative pain intensity, sedation scores, adverse events, time to the first dose of postoperative analgesic and cumulative analgesic requirement in 24 hours were recorded. Data were expressed as mean +/- SD. RESULTS: Patients in the clonidine group displayed greater hemodynamic stability perioperatively and the isoflurane requirement was also reduced (30% less). The postoperative analgesic requirement was less (1.5 +/- 1.3 vs. 2.2 +/- 1.3 dose, P < 0.05) and the time for the first dose of analgesic was prolonged (411 +/- 565 vs. 264 +/- 441 min) in comparison with the placebo group but no statistic difference was found. CONCLUSIONS: Oral clonidine premedication helped to provide perioperative hemodynamic stability, spared the use of isoflurane and reduced the requirement of postoperative analgesia so as to smoother the way to recovery in patients undergoing LC.

Administration, Oral↗

Fatal pulmonary embolism in a child undergoing extra-ventricular drainage surgery--a case report.

Thromboembolism is rather common in neurological patients and patients with brain tumor, who are bed-ridden or with partial immobile limb. In serious instances morbidity and mortality are inevitable. We present a case report on a fatal pulmonary embolism in a 2-year-old girl who underwent extra-ventricular drainage procedure under general anesthesia for occipital subdural effusion, a sequela of the former surgery undertaken to remove the choroid plexus papilloma 13 days ago. Sudden cardiac arrest occurred during induction of anesthesia and she finally succumbed in spite of vigorous cardiopulmonary resuscitation. Transthoracic and transesophageal echocardiography performed in the course of resuscitation disclosed thrombi of various sizes scattering in right atrium, the right ventricle, main pulmonary trunk, and the left pulmonary artery. The cause of death was thought to be severe obstruction of right ventricular outflow tract by large thrombi. The etiological factors which possibly led to the thrombosis were discussed, and the methods of diagnosis and treatment were also explored.

Brain Neoplasms↗

Anesthetic management of a parturient with Eisenmenger's syndrome and preeclampsia during cesarean section--a case report.

It has been recommended that women with Eisenmenger's syndrome (ES) are better not to become pregnant and pregnancy may justifiably be terminated by artificial abortion to avoid high maternal mortality and coherent fetal mortality. We present a case report about a parturient with ventricular septal defect (VSD) and ES who received general anesthesia for Cesarean section (C/S) because of preeclampsia, as a result of which she finally succumbed to an episode of intraoperative hypotension in spite of vigorous cardiopulmonary resuscitation. The death was thought to be precipitated by continuous deterioration of maternal health during the 3rd trimester of gestation. The anesthetic management of pregnant ES patients in confinement was reviewed and discussed, and the possible etiological factors relevant to the tragic outcome were also explored.

Adult↗

Anesthetic management in a parturient with progressive systemic sclerosis during cesarean section--a case report.

This case report concerns a successful Cesarean section (C/S) delivery in an expectant woman affected with progressive systemic sclerosis (PSS) with clinical manifestations of severe pulmonary hypertension (PH), cor pulmonale, severely restrictive ventilatory impairment, pregnancy-induced hypertension (PIH), and esophageal dysfunction under general anesthesia (GA). This is an extremely rare condition in obstetrics and the victim is usually in a great peril of conception, delivery, surgery and anesthesia because of poor pulmonary and cardiac reserves. We herewith reported our experience in two GAs given uniquely to the same patient who was affected with the disorder and discuss the problem.

Adult↗

Incidence and risk factors of guidewire-induced arrhythmia during internal jugular venous catheterization: comparison of marked and plain J-wires.

STUDY OBJECTIVES: To compare the incidence and risk factors of guidewire-induced arrhythmia (GIA) during internal jugular venous catheterization (IJV). DESIGN: Prospective study. SETTING: Operating rooms at a medical center. PATIENTS: 303 ASA physical status I, II, III, and IV patients undergoing elective surgery. INTERVENTIONS: All patients were cannulated with the central venous catheters placed via the right internal jugular vein after induction of anesthesia. They were randomly divided into two groups. In one group, we used a marked J-wire and inverted up to, but not beyond 20 cm (Group M, n = 127). In the other group, a plain unmarked J-wire was used and inserted at will (Group UM, n = 176). All IJV catheterizations were performed by residents, and the length of J-wire inserted was then measured. MEASUREMENTS AND MAIN RESULTS: Types of arrhythmia [eg, premature atrial contraction (PAC) or premature ventricular contraction (PVC)] were interpreted by attending anesthesiologists on lead II ECG. Patients in Group UM had a significantly greater incidence of GIA than those in Group M (28.4% vs. 3.9%; p < .005). However, in both groups, PAC occurred more frequently than PVC. Factors such as the inserted length of guidewire longer than 20 cm, body height less than 170 cm, and female gender were significantly associated with GIA (p < 0.005). CONCLUSIONS: Limiting the length of the guidewire insertion to less than or equal to 20 cm for right IJV catheterization by using a marked J-wire will reduce the incidence of GIA. We recommend the use of a marked J-wire for IJV catheterization.

Adolescent↗

Transesophageal indirect atrial pacing for open-heart surgery in children.

BACKGROUND: Transesophageal atrial pacing (TAP) has been successfully applied for clinical use for more than 30 years. Not only for cardiac pacing, or diagnosis and treatment of rhythmic disturbance but also for assessing the presence and severity of coronary artery disease and maintaining adequate heart rate can TAP provide satisfactory effect. In this study we applied TAP on children undergoing the cardiac surgery to evaluate its efficacy and side effects during such major surgery. METHODS: Twenty-four children (15 M and 9 F) undergoing open-heart surgery with informed consents were included in this study. After induction of anesthesia the bipolar pacing electrode (Tapcath, Arzco Medical Electronics) was inserted into esophagus through the nose until the ideal site for atrial pacing was found by monitoring the esophageal ECG lead (lead I), and then initiation of atrial pacing was performed by applying the transesophageal cardiac stimulator (Arzco Medical Electronics). Continuous ECG, arterial blood pressure and central venous pressure (CVP) were simultaneously monitored and recorded. Patient's height, inserted length of the pacing electrode, current and pulse duration for effective atrial pacing were also recorded. RESULTS: The effective rate for initiating sinus tachycardia (atrial capture) by applying TAP was 79.2% (19/24) in our study. For effective atrial pacing the average current was 11.6 +/- 2.4 mA, the average stimulus pulse duration was 4.8 +/- 1.0 ms, and the average inserted length of bipolar electrode was 19.1 +/- 2.2 cm. CONCLUSIONS: TAP method can be applied satisfactorily in children undergoing cardiac surgery. If urgent cardiac pacing must be applied in these patients TAP would be a choice.

Arrhythmias, Cardiac↗

Is postextrasystolic potentiation dependent on Starling's law? Biplane angiographic studies in normal subjects.

The cineangiograms of 26 normal subjects were analyzed to study the effect of Starling's mechanism on postextrasystolic potentiation. The end-diastolic volumes (single plane and biplane) of the left ventricle were similar in the regular sinus beat before an extrasystole and sequential sinus beats after an extrasystole. However, the ejection fraction, mean normalized systolic ejection rate, mean velocity of fiber shortening and long-axis shortening were consistently larger in the first sinus beat after an extrasystole. We conclude that postextrasystolic potentiation is independent of left ventricular end-diastolic volume in normal human hearts and the compensatory pause after an extrasystole does not result in increased end-diastolic volume.

Angiography↗

Application of Auger electron spectroscopy for surface chemical analysis of Avcothane.

The effect of the exposure to air or to the substrate during the solvent casting process on the surface chemical composition of Avcothane, a blood compatible biomaterial, was studied by employing Auger electron spectroscopy. The surface layer of 10-15A thickness was analyzed without sputtering, but for the studies probing a deeper layer, argon ion sputtering at a low enough voltage to prevent artifacts was utilized. It is found that the air facing surface which is the blood contact surface contains a greater amount of silicone polymer and a much lower amount of the urethane hard segment in the first 10-15A-deep layer than in the comparably thick layer of the substrate surface. However, the depth-composition profile obtained by sputtering indicate that, probably at a deeper depth, the chemical compositions in terms of silicone polymer and hard segment is comparable both in the air side and the substrate side.

Carbon↗

Surface chemical analysis of Avcothane and Biomer by Fourier transform IR internal reflection spectroscopy.

During the solvent casting process, one side of the polymer film is exposed to air while the other side is in contact with a substrate, used as a mold. We have studied the effect of this difference in exposure during casting on the chemical composition of two types of segmented polyurethane, Biomer and Avcothane, by using Fourier transform IR internal reflection spectroscopy. Also, a depth-composition profile was obtained by placing a thin barrier film between the reflection plate and the polymer film. In Avcothane, the air side, which is the blood-contact side, contains a greater amount of the soft segment than the substrate side, and this is more pronounced in the layer closer to the surface. The anisotropy in composition is more drastic when the silicone content is compared. In a layer about 1.5 mu thick, one can detect a greater amount of silicone in the substrate side than in the air side. However, when one averages the concentration in a layer of about 0.8 microns the trend in reversed; i.e., the greater amount of silicone is now present in the air side than in the substrate side. In Biomer films, the anisotropy in chemical composition is less pronounced. Only a modest increase in the relative content of the soft segment/hard segment is observed in the air side when a depth-composition profile is obtained.

Biocompatible Materials↗