Biomedical subjects
Publications and source records attributed to J L Chong.
An expansile temporal bone lesion above the temporomandibular joint (TMJ) in a 55-year-old woman was initially diagnosed as pigmented villonodular tenosynovitis. Preoperative embolization of the tumor had resulted in excessive tumoral hemorrhagic pigment. The surgical and CT findings suggested that the TMJ was not involved, and a final diagnosis of giant cell tumor was made.
The potential of pentoxifylline (PTX) to modify systemic inflammatory responses and lung injury following cardiopulmonary bypass (CPB) was studied in 20 patients undergoing elective coronary artery surgery. Ten control patients were compared with ten patients who received a PTX infusion of 1 mg kg-1 h-1 during surgery. Intra-vascular pulmonary leukocyte sequestration was observed in neither group following discontinuation of CPB. Plasma elastase-alpha-1-antiprotease complex rose three-fold from baseline in both groups to peak at sternal closure. No significant plasma interleukin-1 (IL-1) response was detected. Plasma interleukin-6 (IL-6) rose in both groups from baseline to peak 4 h postoperatively. There was no correlation between plasma levels of elastase complex, IL-1 or IL-6 and impairment of postoperative oxygenation. CPB was associated with significant postoperative hypoxaemia and systemic release of neutrophil elastase and IL-6 but PTX, at the given dose, did not abrogate these responses.
Supraventricular tachyarrhythmias following coronary artery bypass grafting are a common cause of postoperative morbidity, with a reported incidence of 10-40%. Two techniques of myocardial protection were assessed to determine their influence on the occurrence of postoperative supraventricular tachyarrhythmias. Group I (n = 82) received cold potassium cardioplegia combined with topical hypothermia and systemic cooling to 28 degrees C. Group II (n = 88) were protected by intermittent aortic cross-clamping with a systemic temperature of 32 degrees C. The overall incidence of atrial fibrillation/flutter was 22.3%. No significant difference was detected in the incidence of clinically important atrial fibrillation/flutter between the two groups [21/82 (25.6%) in group I versus 17/88 (19.3%) in group II, P > 0.25]. There was a positive association with age: in patients over 60 years the incidence of arrhythmias (31.8%) was significantly greater than in those less than 60 years (12.9%), P < 0.01. Sex, cardiopulmonary bypass times, aortic cross-clamp times, number of coronary grafts, end-operative creatine kinase myocardial band isoenzyme, right coronary endarterectomy and perioperative myocardial infarction had no association with the occurrence of postoperative atrial tachyarrhythmias.
The anesthetic and postoperative management of cardiac surgical patients was modified to achieve an early return to spontaneous ventilation. A total of 278 patients were studied to determine the effect of this change. Patients in group I (n = 198) were managed in a cardiac surgical recovery area according to the new policy. Group II (n = 80) was a comparable group of patients operated upon before this change. The median duration of postoperative ventilation was reduced from 5 hours in group II to 1 hour in group I, and the time to extubation was reduced from 7 hours to 2 hours, respectively. There were no major postoperative complications resulting from this change. The factors that influence the duration of postoperative ventilation are discussed.
Sedation using combined intravenous midazolam and fentanyl is a popular technique for minor gynaecological procedures. However, it is fraught with inconsistency in efficacy and has a greater tendency to perioperative oxygen desaturation. Fifty female ASA I patients scheduled for minor gynaecological procedures were given intravenous midazolam and fentanyl before surgery started. Intraoperative excessive movement that interfered with surgery and failure to maintain a patient airway were noted. Perioperative oxygen saturation was monitored with the pulse oximeter. In another group of 50 female ASA I patients, intravenous thiopentone was given and anaesthesia maintained with 67% nitrous oxide in 33% oxygen and 0.5% of isoflurane via a face mask. Results showed that 10% of the sedated patients had excessive movements that interfered with surgery, of which 6% needed a general anaesthetic. Twenty-two percent of the sedated patients needed maintenance of airway perioperatively. Perioperative oxygen desaturation was profound in incidence and degree in the sedated patients whereas no patient who received general anaesthesia desaturated. The perioperative incidence of desaturation in the sedated patients was 46%. Intraoperatively, 28% (p < 0.001) of the sedated patients had oxygen saturation in the range of 85 to 90% and 18% of them (p < 0.01) had oxygen saturation of less than 85%. Postoperatively 8% of the sedated patients had oxygen saturation of 85 to 90%. We conclude that general anaesthesia is more efficacious and safer than sedation in patients scheduled for minor gynaecological procedures. The same minimum standard of monitoring applied to general anaesthesia should be used for sedated patients.
OBJECTIVE: To evaluate outcome in patients managed outside an intensive care unit after open heart surgery. BACKGROUND: The high cost of cardiac surgery is mainly due to the needs of traditional postoperative care. The requirements for intensive care and treatment has decreased with improvements in techniques of cardiac surgery and anaesthesia. In this setting the need to continue to depend on intensive care units for the recovery of cardiac surgical patients is questionable on clinical and economic grounds. DESIGN: Postoperative outcome in 245 patients over a four month period was studied prospectively. PATIENTS: Mean age of the patients was 63.2 years. They underwent a wide variety of operative procedures. Ninety percent of them recovered in a dedicated three bed cardiac surgical recovery area where the management protocol led to rapid extubation and step down in dependency care. RESULTS: Median time for ventilatory support was 90 minutes after transfer to the area. Only five patients were subsequently admitted to the general intensive care unit for prolonged respiratory and cardiac support. Ten patients were electively admitted to the general intensive care unit. Two deaths occurred in hospital in this group (0.8%). Four patients were ventilated for 24 hours in the recovery area itself and made an uncomplicated recovery. CONCLUSION: This study confirms that over 90% of patients undergoing cardiac surgery would recover safely and be treated effectively in a more economical area than intensive care.
Difficult intubation has been much discussed in the anaesthetic literature. The incidence of difficult intubation (11:560) was higher in obstetric patients (6:277) as compared to gynaecological patients (5:283) in our hospital. We tested the Mallampati's classification as a predictor of difficult intubation in 277 obstetric and 283 gynaecological patients. We recommend that Mallampati's classification can be used reliably (p less than 0.05) to predict difficult intubation in obstetric but not in gynaecological patients.
Forty-five pregnant females were studied with respect to the effectiveness of denitrogenation by the 3, 5, 7 and 9 rapid vital capacity breaths, and 3 to 5 minutes of normal breathing. It was found that 3 to 9 vital capacity breaths cannot effectively denitrogenate a pregnant patient when a circle breathing system with a gas flow of 8 litres/min is used. At least 3 minutes of normal tidal volume breathing should be given for proper denitrogenation or preoxygenation if the circle system is used for such a purpose.
A study of 80 patients with strabismus undergoing correctional surgery under general anaesthesia was done. A comparison was made with regards to the incidence of oculocardiac reflex between patients premedicated with intramuscular atropine 0.015 mg/kg and non-premedicated patients. We found that premedication with atropine reduces the incidence and the morbidity of the oculocardiac reflex.
We compared the difference in denitrogenation (by intermittent measurement of arterial tension, PaO2) in 45 parturients at term when preoxygenated with 4, 6 or 8 rapid vital capacity breaths and 5 minutes of tidal volume breathing. Oxygen, at 8 litres min-1, was delivered through a facemask via a circle absorber with a 2 litre reservoir bag. Higher PaO2 was produced with 5 minutes of tidal volume breathing. This differed significantly from the PaO2 produced by 4, 6 or 8 rapid vital capacity breaths (p less than 0.01).
A quantitative measurement of the prophase Giemsa banding patterns in chromosome 20 of the peripheral blood samples obtained from seven patients with medullary carcinoma of the thyroid (MCT), three nonsymptomatic family members of MCT patients, and three normal controls has revealed no differences in the short arms of the two homologs. More specifically, measurements of band from 20p 12.1 to 20p 12.3 and statistical analysis of the mean ratio between these bands have given no indication of intersitial deletion in chromosome 20p of MCT patients.