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Biomedical subjects

E R Townsend

Publications and source records attributed to E R Townsend.

At least 37 records · Page 2Linked to original sources
PubMed1992

Early and late outcome after diagnostic thoracoscopy and talc pleurodesis.

Although thoracoscopy is now recognized to be of both diagnostic and therapeutic value, the risks of this procedure have not been fully addressed. We retrospectively reviewed our experience with 100 patients who underwent 110 thoracoscopies during the period January 1989 to February 1991. Sixty-five men and 35 women (ratio of 1.9:1) underwent thoracoscopy using general anesthesia and intubation with a double-lumen endotracheal tube. The mean age was 64.2 +/- 11.6 years (range, 13 to 85 years). The diagnosis was established in 48 (85.7%) of the 56 patients with undiagnosed pleural effusions. Forty-four patients were referred for therapeutic thoracoscopic talc pleurodesis. Pleurodesis was successful in 42 patients (95.5%). Four patients (4%) had five postoperative complications (two bronchopleural fistulas, two chest infections, and one arrhythmia). Five patients (5%) died after thoracoscopy; mean age was 67.8 +/- 8.1 years (range, 55 to 77 years). The causes of death were cardiac arrest in 2, respiratory failure in 1, and malignant cachexia in 2. The findings of this study confirm that thoracoscopy can achieve high rates of diagnostic and therapeutic success but is not without attendant mortality in a high-risk patient population.

Aged↗
PubMed1992

Use of endotracheal silicone stents for relief of tracheobronchial obstruction.

In this article we describe our initial experience with bifurcated and longitudinal silicone stents that can be inserted entirely endoscopically. A total of 10 patients were stented; half had upper airways obstruction resulting from malignant disease and half had anastomotic obstruction after single-lung (3 patients), double-lung (1 patient), or heart-lung transplantation (1 patient). All patients derived immediate relief of life-threatening stridor. Stents were in place for between 5 days and 2 1/2 years (mean, 232.9 days). In the patients with malignant disease, the stents have provided effective relief from stridor for the remainder of their lives. In the transplant recipients, the medium-term results are encouraging, with the stents providing effective relief from stridor, although the longitudinal stents have been associated with distal migration, requiring that the stents be replaced on up to five occasions. The stents have not been associated with infection in the nonimmunosuppressed patients, and during the relatively short follow-up period there has been no tissue reaction to the material.

Adult↗
PubMed1992

Elective pneumonectomy: factors associated with morbidity and operative mortality.

We have retrospectively reviewed hospital records of 197 consecutive patients undergoing pneumonectomy for neoplastic disease between 1985 and 1990 to identify predictors of outcome. Seventeen of the 197 patients died during their hospital stay (8.6%; 95% confidence intervals, 6.7% to 11.2%). The most significant predictors of in-hospital mortality were presence of coexisting medical conditions (p less than 0.001), respiratory function tests showing an obstructive picture with a forced expiratory volume in 1 second/forced vital capacity ratio of less than 0.55 (p less than 0.001), 24-hour fluid replacement of more than 3 L (p less than 0.05), postoperative pulmonary edema (p less than 0.001), respiratory tract infection with positive sputum culture (p less than 0.01), postoperative renal failure (p less than 0.001), and cardiac arrhythmias (p less than 0.001). There were 232 postoperative management, problems occurring in 197 patients. The most significant predictors of postoperative morbidity were continued cigarette smoking up to the time of operation (p less than 0.05), perioperative blood loss or more than 2 L (p less than 0.05), and infusion of more than 3 L of fluid in the first 24 hours (p less than 0.05). Although retrospective analyses must be interpreted with caution, this study has identified preoperative and perioperative factors associated with in-hospital morbidity and mortality after pneumonectomy.

Adult↗
PubMed1992

Surgery for bullous disease of the lung.

Between July 1986 and December 1990, 22 patients underwent 23 operative procedures for bullous disease at Harefield Hospital. Their ages ranged from 21 to 71 years (mean 49.8 years). There were 18 males and 4 females. All patients were operated upon for symptoms of exertional dyspnoea. Four patients belonged to functional class IV, 11 to class III and 3 to class II. In 80% of patients, computed tomography was performed as part of the preoperative assessment. The bullae were dealt with in 13 patients on the right side, in 7 on the left and in 2 bilaterally. Six patients were treated by a modified Monaldi procedure and 17 by bullectomy. There was no operative mortality. Mean hospital stay was 14.8 days. Two patients required a second operative procedure during their hospital stay for persistent air leak and pneumothorax. One of these had a Monaldi procedure in the first instance but underwent bullectomy later. All patients improved symptomatically, 10 patients moving up two grades and 12, one grade. Mean FEV1, FVC and MVV were significantly improved postoperatively, but there were no significant changes in RV or TLC. A graduated exercise test was performed in 4 patients. Improvements were seen in ventilation and oxygen consumption at anaerobic threshold and maximum exercise. Surgery for bullous disease improves symptoms by reducing airway obstruction and increasing ventilatory capacity on exercise.

Adult↗
PubMed1992

Folded lung: a masquerader of malignancy.

Four cases of folded lung were observed over an 8-year period up to 1990. Because of suspected malignancy, three patients underwent exploratory thoracotomy, without subsequent morbidity or mortality, but the fourth patient declined surgery. Although folded lung may have characteristic computed tomographic features, these may be mimicked by carcinoma. If the patient is fit enough, exploratory thoracotomy is advisable in order to establish the diagnosis and permit resection of the lesion, if indicated, while avoiding the risks entailed by false negative CT scan and needle biopsy.

Aged↗
PubMed1990

Method of endoscopic esophageal intubation using a rigid esophagoscope.

Endoscopic intubation of malignant esophageal strictures carries a substantial risk of esophageal perforation. We have developed a method of endoscopic intubation that reduces to a minimum the elements of the procedure that have to be performed "blind." The use of this method has been associated with a reduction in perforation rates when compared with other series.

Equipment Design↗
PubMed1990

Oesophageal resection after instrumental perforation.

Between 1981 and 1987, 11 patients underwent oesophageal resection following endoscopic perforation of the oesophagus. They had a median age of 67 years with a range of 36 to 88 years. They all were managed either by one- or two-stage oesophageal resections. Six patients were perforated at other hospitals, 5 on site. Seven had carcinoma of the middle or lower third of the oesophagus, 2 of these were perforated at attempted palliative intubation. Four had benign peptic strictures perforated during dilatation. Seven were resected within the first 24 hours and 4 between 2 and 10 days after perforation. All 4 patients with benign disease survived but 4 of the 7 patients with cancer died giving an operative mortality of 36.3%. Respiratory complications were the most common postoperative problem: all deaths were attributed to respiratory failure. Perforation of the thoracic oesophagus carries a high mortality. Resection after perforation in benign strictures may be life saving in a potentially lethal condition but resection after perforation, even in operable cancer, still carries a high mortality.

Adult↗
PubMed1990

Palliative intubation of malignant oesophageal strictures.

A 6-year experience (1981-1987) of palliative intubation of irresectable malignant oesophageal strictures is reported in 110 patients with a mean age of 70.3 (range 41-90) years. Pulsion intubation was performed on 71 patients, 11 (15.5%) of whom died, and traction intubation on 39 with 6 (15.4%) deaths. Seven deaths resulted from instrumental perforation, but six other patients survived perforation and left the hospital in satisfactory condition. Mean in-patient stay was 8 (range 1-26) days. Non-fatal tube-related complications were more common in pulsion intubation, but was found to be highly effective in relieving dysphagia, with shortened hospital stay (mean 6 days) and acceptable morbidity and mortality rates. These results indicate the trend towards, and the increased safety of, pulsion intubation.

Aged↗
PubMed1989

Mediastinoscopy in the investigation of primary mediastinal lymphadenopathy.

Mediastinoscopy was introduced by Carlens (1) in 1959 to obtain lymph node biopsies from the superior mediastinum in patients with bronchogenic carcinoma. The technique has been widely accepted for clinical staging as a guide to operability and prognosis. We report on a consecutive retrospective series of 110 patients undergoing mediastinoscopy between 1982-1986 for primary mediastinal lymphadenopathy in order to assess the diagnostic value and safety of the procedure. Mediastinoscopy gave a positive histological diagnosis in 74.5% of cases with no false negative results. There were no deaths and one complication only (pneumothorax). This study shows mediastinoscopy to be a safe, accurate and cost effective procedure minimising hospital stay and allowing appropriate treatment to be immediately commenced upon diagnosis. Mediastinoscopy obviates the need for expensive computed tomography or nuclear magnetic resonance scans and we conclude that it is the investigation of choice for primary mediastinal lymphadenopathy after confirmation by plain chest radiography.

Adult↗
PubMed1988

Hidden foreign body as a cause of recurrent hemoptysis in a teenage girl.

Hemoptysis in a teenage girl caused by a foreign body located in the posterior segment of the left lower lobe is described. The patient was seen four years after the initial inhalation. The importance of taking a meticulous history and the use of computed tomography in the localization of the lesion are emphasized, and the use of the fiberoptic bronchoscope in peripheral lesions and in the investigation of hemoptysis is discussed.

Adolescent↗
PubMed1988

Splenic herniation. Case report.

A case of splenic herniation complicated by spurious hypertension is described. A misleading provisional diagnosis was made despite computerised tomography (CT Scan). Diaphragmatic herniation is discussed and the use of computerised tomography in the diagnosis of masses arising from the posterior aspect of the diaphragm is emphasized.

Adult↗
PubMed1983

Thromboxane synthesis by sources other than platelets in association with complement-induced pulmonary leukostasis and pulmonary hypertension in sheep.

Infusion into sheep of plasma containing zymosan-activated complement produces leukopenia, pulmonary leukostasis, and pulmonary artery hypertension. We previously demonstrated a close relationship between the pulmonary vascular response and elevations of plasma thromboxane. We have investigated the source of thromboxane synthesis in this model. Plasma containing zymosan-activated complement added to whole blood did not stimulate thromboxane synthesis. This observation suggested that leukocytes do not synthesize thromboxane directly in response to complement added to whole blood did not stimulate thromboxane synthesis. This observation suggested that leukocytes do not synthesize thromboxane directly in response to complement. Sheep rendered severely thrombocytopenic by the administration of antiplatelet serum responded to complement infusion in the usual way. Pretreatment with aspirin (10 mg/kg) protected sheep against the pulmonary vascular response and completely blocked thromboxane synthesis. Transfusion of functional platelets did not restore these responses. Twenty-four hours after aspirin treatment, in vivo thromboxane synthesis was significantly greater than platelet thromboxane synthesis in vitro. Thromboxane is synthesized by a tissue which recovers cyclooxygenase enzyme activity at a rate that is more rapid than platelet turnover. Sheep lung synthesizes thromboxane actively in vitro. It is postulated that leukocytes exposed to activated complement components damage pulmonary vascular endothelial cells and stimulate synthesis of thromboxane A2 which causes pulmonary vasoconstriction.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Effect of carotid body denervation on arousal response to hypoxia in sleeping dogs.

We studied the arousal and ventilatory responses to hypoxia during sleep in three trained dogs, before and 1-4 wk after carotid body denervation (CBD). During the studies the dogs breathed through a cuffed endotracheal tube inserted via a chronic tracheostomy. Eucapnic progressive hypoxia was induced by a rebreathing technique, and arterial O2 saturation (Sao2) was measured with an ear oximeter. Sleep stage was determined by electroencephalographic and behavioral criteria. Following CBD, all dogs exhibited hypoventilation under resting conditions; hypoxic ventilatory responses during wakefulness, slow-wave sleep (SWS), and rapid-eye-movement (REM) sleep were less than 10% of control. Prior to CBD, hypoxic arousal occurred at Sao2 of 83.2 +/- 4.6% (mean +/- Se) during SWS and 70.6 +/-2.2% in REM sleep. Following CBD, arousal failed to occur during progressive desaturation to 60% in SWS and 50% in REM sleep, at which levels hypoxia was arbitrarily terminated. In a few studies following CBD where rebreathing was allowed to continue, the dogs occasionally failed to arouse at all and require active resuscitation. The results indicate a critical role for the carotid chemoreceptors in mediating the arousal response to hypoxia.

Animals↗
PubMed1981

Carotid chemoreceptors in ventilatory responses to changes in venous CO2 load.

We examined the role of the carotid chemoreceptors in the ventilatory response to changes in venous CO2 load in 12 awake sheep using a venovenous extracorporeal perfusion circuit and two carbon dioxide membrane lungs (CDML). Three of the sheep had undergone surgical denervation of the carotid bodies (CBD). In the nine intact sheep, as CO2 was removed from or added to the peripheral venous blood through the CDML under normoxic conditions, there was a linear relationship between the rate of pulmonary CO2 excretion (VCO2) and the resulting rate of ventilation over a VCO2 range of 0--800% of control, so that arterial PCO2 remained close to isocapnic. In contrast, in the three CBD sheep, the ventilatory response to changes in VCO2 was significantly decreased under normoxic conditions, resulting in marked hypercapnia. The results indicate that the carotid chemoreceptors exert a major influence on the ventilatory response to changes in venous CO2 load.

Animals↗
PubMed1981

Preservation of platelets during extracorporeal circulation in sheep. A comparison between aspirin and sulfinpyrazone.

We studied the effect of aspirin and sulfinpyrazone on changes in platelet count, thromboxane B2 production, and pulmonary vascular resistance following the onset of veno-venous membrane oxygenator perfusion in sheep. Perfusion under identical circumstances was performed in three groups of animals, with one group serving as controls, one group receiving pretreatment with 1.5 grams of sulfinpyrazone iv, and one group receiving pretreatment with aspirin 50 mg/kg, iv. Both aspirin and sulfinpyrazone eliminated the rise in thromboxane B2 and the increase in pulmonary vascular resistance seen in control animals. Platelet preservation was improved significantly with sulfinpyrazone pretreatment, but not affected by aspirin. We conclude that sulfinpyrazone and aspirin have different mechanisms of action as far as platelet preservation during extracorporeal perfusion is concerned. The major difference may be sulfinpyrazone's ability to reduce platelet adhesion to the membrane surface. Since both aspirin and sulfinpyrazone eliminated the pulmonary vascular-response, but only sulfinpyrazone preserved platelets, it is apparent that the pulmonary vascular response is more closely related to thromboxane synthesis than to platelet disappearance.

Animals↗
PubMed1981

Role of the carotid body and of afferent vagal stimuli in the arousal response to airway occlusion in sleeping dogs.

We studied the independent effects of bilateral carotid body denervation and bilateral cold blockade of the vagus nerves on the arousal response to airway occlusion during sleep. Dogs breathed through a cuffed endotracheal tube inserted via a chronic tracheostomy, and airway occlusion was imposed at end-expiration and maintained until the moment of arousal. Arterial O2 saturation (SaO2) was measured with an ear oximeter, and sleep stage was determined by electroencephalographic and behavioral criteria. Mean +/- SE SaO2 values at arousal were 88.7 +/- 2.7% during slow-wave sleep, and 84.9 +/- 3.5% during rapid-eye-movement sleep (0.05 less than p less than 0.1). After carotid body denervation (2 dogs), arousal SaO2 values were less than 60% during slow-wave sleep and less than 50% during rapid-eye-movement sleep, at which time airway occlusion was arbitrarily terminated. In a few studies after denervation, when airway occlusion was maintained beyond these values, the dogs occasionally failed to arouse at all, and resuscitation was required. Bilateral cold blockade of the vagus nerves (2 dogs) resulted in no significant change in SaO2 at arousal. We concluded that the arousal response to airway occlusion is mediated primarily by the carotid bodies.

Afferent Pathways↗