Transbronchial needle aspiration of mediastinal lymph node.

In Malaysia, transbronchial needle aspiration (TBNA) is a relatively new procedure performed only in a handful of respiratory centres. We reviewed TBNA of mediastinal lymph node performed in Hospital Tengku Ampuan Afzan (HTAA) to determine the yield and its complications. Data was retrieved from endoscopy databases and patients' records, CT thorax images and all cytological and histological slides were reviewed. Twenty-five patients had TBNA performed. TBNA was positive in 15 patients (60%). Overall, 80% had confirmed malignancy after bronchoscopy. Only four patients had documented bleeding after TBNA and in two of them, bleeding stopped spontaneously and another two patients required diluted adrenaline to stop the bleed. No mortality was reported from this procedure. Hence, TBNA is a safe procedure.

Giant cell tumour of bone with late presentation: review of treatment and outcome.

PURPOSE: To review cases of giant cell tumour of bone or osteoclastoma managed at the University Malaya Medical Center, University of Malaya, Kuala Lumpur, from January 1990 to December 1999. METHODS: Medical records of all patients with musculoskeletal tumours were reviewed. Demographic data, clinical presentation, surgical management, and clinical outcomes were reviewed retrospectively. RESULTS: Most of the 31 patients who were treated for giant cell tumour of bone presented late on the basis of the duration of their symptoms and radiological features. Five of the patients had been referred for local recurrences. 26 patients were treated for primary tumours: 18 needed wide excision, 7 curettage, and one amputation. The joint could not be preserved and arthrodesis was performed for 11 patients. Three (12%) of the 26 patients had local recurrence during a mean follow-up of 60 months, including one (6%) who had recurrence after wide excision and 2 (29%) after curettage. Pulmonary metastasis was noted in 4 cases, 2 of which were confirmed histologically. CONCLUSION: Even in an advanced stage of disease, good clinical outcomes can be achieved with adequate excision and appropriate reconstruction. For lesions around the knee, autologous rotational grafting is a good alternative method of reconstruction.

Components of excess ventilation in patients initiated on mechanical ventilation.

OBJECTIVE: To determine the causes of excess minute ventilation in patients initiated on mechanical ventilation. DESIGN: Prospective study of recently intubated, mechanically ventilated patients. SETTING: The medical ICU in a county hospital. PATIENTS: Fifty-two mechanically ventilated medical ICU patients were studied within 36 hrs of intubation. Patients were all supported with volume-cycled ventilation in the assist-control mode. INTERVENTIONS: Timed expired gas collection and an arterial blood gas. MEASUREMENTS AND MAIN RESULTS: Measurements of minute ventilation and CO2 production (VCO2) were made from a timed expired gas collection. PaCO2 was sampled during the gas collection and deadspace was determined. Minute ventilation, VCO2, deadspace, and PaCO2 values in the patients were compared with predicted normal values, and excess minute ventilation due specifically to each component was calculated. Patients were separated clinically into groups: adult respiratory distress syndrome (ARDS), sepsis, obstructive lung disease, pneumonia, and drug overdose. Comparisons were then made between groups. Excess minute ventilation for the entire study population was secondary to increased deadspace (39%), low PaCO2 (36%), increased VCO2 (15%), and the interactive effect of deadspace and VCO2 (10%). VCO2 contributed little to excess minute ventilation early in respiratory failure, even in the ARDS and sepsis groups. Deadspace contributed significantly to excess minute ventilation in all groups, especially in the ARDS group, where it accounted for 53% of the excess ventilation. Low PaCO2 set-point was the predominant cause of excess minute ventilation in the sepsis group, where it contributed to 57% of their total excess minute ventilation. CONCLUSIONS: Although all groups initiated on mechanical ventilation had an excess ventilatory requirement, the contribution of individual components varied considerably between clinical groups.

Acute dissection of the internal mammary artery: a fatal complication of coronary artery bypass grafting.

A case of acute traumatic dissection of the right internal mammary artery is presented in a patient who had both IMAs grafted for recurrent angina 10 years after initial vein coronary revascularisation. The event was mistaken for spasm, but because of severe circulatory collapse no time was available to treat the patient appropriately. The purpose of this report is to facilitate the early recognition and avoidance of this potentially fatal complication.

Comparative effects of transdermal clonidine and oral atenolol on acute exercise performance and response to aerobic conditioning in subjects with hypertension.

We compared the effects of transdermal clonidine and oral atenolol on acute exercise performance and on conditioning response to an 8-week program of regular aerobic exercise in young, otherwise healthy subjects with mild hypertension. The study was a double-blind, randomized, parallel-group study with placebo control. Twenty-seven subjects (11 receiving transdermal clonidine, 8 receiving oral atenolol, and 8 receiving placebo) completed the study. Atenolol controlled blood pressure in all 8 subjects, vs 6 of 11 in the transdermal clonidine group and 0 of 8 in the placebo group. Both active drugs lowered systolic blood pressure during exercise. With clonidine treatment, the antihypertensive effect during exercise was smaller and was observed only at low and moderate workloads. Acute exercise performance (subjects receiving drug but still unconditioned) was assessed by endurance time at a constant workload equal to the highest workload completed on a previous 2-minute incremental exercise test. Endurance time was reduced 35% by atenolol but not by transdermal clonidine or placebo. Neither active drug interfered with the progress of the conditioning program, as measured by gradual lengthening of exercise time. However, as assessed by change in oxygen uptake standardized to a heart rate of 170 beats per minute, the improvement in conditioning was twice as great in subjects receiving transdermal clonidine and placebo (+20%, +18%) as it was in those receiving atenolol (+8%). Subjects receiving placebo and transdermal clonidine lost weight; subjects receiving oral atenolol gained weight. The changes in weight were small.

Extreme dyspnea from unilateral pulmonary venous obstruction. Demonstration of a vagal mechanism and relief by right vagotomy.

A 43-yr-old woman developed severe exertional dyspnea after an unsuccessful attempt to correct a total right anomalous pulmonary venous connection. A clotted anastomosis resulted in unilateral pulmonary venous obstruction. Investigation excluded airway disease, left ventricular failure, and severe pulmonary hypertension as the cause of dyspnea. Exercise studies demonstrated a markedly abnormal ventilatory pattern consistent with excess vagal stimuli to the respiratory center. Temporary and then permanent vagal interruption markedly altered the respiratory pattern and improved her functional status from New York Heart Association Class III to Class I, confirming that vagal afferents were the cause of the dyspnea.

Effect of respiratory alkalosis during exercise on blood lactate.

A biofeedback model of hyperventilation during exercise was used to assess the independent effects of pH, arterial CO2 partial pressure (PaCO2), and minute ventilation on blood lactate during exercise. Eight normal subjects were studied with progressive upright bicycle exercise (2-min intervals, 25-W increments) under three experimental conditions in random order. Arterialized venous blood was drawn at each work load for measurement of blood lactate, pH, and PaCO2. Results were compared with those from reproducible control tests. Experimental conditions were 1) biofeedback hyperventilation (to increase pH by 0.08-0.10 at each work load); 2) hyperventilation following acetazolamide (which returned pH to control values despite ventilation and PaCO2 identical to condition 1); and 3) metabolic acidosis induced by acetazolamide (with spontaneous ventilation). The results showed an increase in blood lactate during hyperventilation. Blood lactate was similar to control with hyperventilation after acetazolamide, suggesting that the change was due to pH and not to PaCO2 or total ventilation. Exercise during metabolic acidosis (acetazolamide alone) was associated with blood lactate lower than control values. Respiratory alkalosis during exercise increases blood lactate. This is due to the increase in pH and not to the increase in ventilation or the decrease in PaCO2.

Plasma separation using a hollow fiber membrane device.

A disposable hollow fiber device was evaluated by collecting approximately 550 ml of normal donor plasma (n = 43) and by performing sham (n = 10) and therapeutic (n = 12) plasma exchanges. Blood was processed at 70 ml per min, and plasma flux averaged 23 (collection) and 25 (exchange) ml per min (mean separation efficiencies of 52 and 60%, respectively). The procedures were tolerated well by all donors and patients. The plasma hemoglobin concentration in separated plasma averaged 1 mg per dl, and cell contamination was negligible (mean of 1, 3, and 6 RBCs, platelets and WBCs/microliter, respectively). There was no evidence of in vivo classical or alternative pathway complement activation as assessed by total hemolytic complement generation (CH50), alternative pathway hemolytic activity (AP50), C3 conversion, or C5 activation, nor were unexpected changes seen in the results of laboratory tests performed after the procedure. Sieving coefficients during sham plasma exchange averaged as follows: albumin, 1.03; IgM, 1.0, IgG, 1.0; IgA, 0.98; factor V, 1.07; factor VII, 0.89; factor VIII, 1.05; and factor IX, 1.19. The device appears to be useful for separation of cell-free plasma from blood during therapeutic plasma exchange procedures.

Blood flow and oxygen consumption in steroid-treated dental pulps.

This study examined pulpal blood flow and oxygen consumption by the dental pulps of dogs. Blood flow was measured by the radioactive microsphere method and oxygen uptake was determined by the indirect Warburg approach. These variables were assessed 2 days after the canine teeth had been exposed and treated with either a cotton pellet impregnated with 1 per cent prednisolone or normal saline. The analysis indicated that the pulpal blood flow as well as the oxygen consumption did not differ between the steriod-treated tooth and the corresponding saline-treated tooth in the same jaw.

Quantitation of blood flow after anterior maxillary osteotomy: investigation of three surgical approaches.

The radioactive microsphere method was used to quantitate preoperative and postoperative blood flows in macaque monkeys when three different surgical approaches for anterior maxillary osteotomy were performed. Despite distinct variations in flap designs among the experimental groups, preoperative and postoperative determinations of blood flow were essentially unchanged. Results of the study suggest that a palatal, labial, or combined mucoperiosteal pedicle should be adequate to preserve the flow of blood to tissues in the osteotomized segment.

Quantification of pulpal blood flow in developing teeth of dogs.

Pulpal blood flow was determined in 32 dogs ranging in age from 6 weeks to 18 months by the isotope fractionation method incorporating diffusible and nondiffusible tracers. Dogs were placed into selected age groups by the developmental status of the canine teeth. For the teeth sampled, the maxillary first, second, and third incisors along with the canines and first molars, pulpal blood flow was determined to be not different in teeth at various developmental stages. For some dental pulps, alveolar mucosa, and bone, the tracers were not determining equivalent blood flows. Because of incomplete trapping of the 7- to 10 mu microspheres and the flow limitation of 86Rb, the 15 mu spheres would appear to be a reliable indicator of "total" blood flow to pulpal tissues. However, in alveolar mucosa and bone, and 15 mu microspheres may not be completely trapped and thus, may underestimate blood flow to these tissues. Within the age range of these dogs, tissue blood flow was not dependent upon the stages of oral development.

Blood flow changes after sagittal split of the mandibular ramus.

Blood flows to various cephalic tissues were determined by the microsphere method before and after unilateral sagittal split of the mandible in macaque monkeys. Significant blood flow decreases were found in certain bony regions of the osteotomized mandible while blood flow to the masseter and medial pterygoid muscles on theosteotomized side was significantly increased. Judicious stripping of the mucoperiosteum and pterygomassteric sling may be an important consideration when planning the sagittal split approach to correct certain mandibular anomalies.

Quantitation of blood flow after Le Fort I osteotomy.

Le Fort I maxillary osteotomies were performed on ten macaque monkeys. The particle distribution method (nondiffusible radioactive microspheres) was used to quantitate local blood flow before and after surgery. Significant reduction in blood flow to the osteotomized maxillary segment was noted in those animals (group S) where the descending palatine vessels were transected. Those animals in which the vascular pedicle was intact (group I) showed decreased blood flow to the attached gingiva and alveolar bone, but palatal tissue blood flow was unchanged or increased. The results reinforce the precept of the importance of maintaining an adequate nutrient pedicle when performing orthognathic surgical procedures.