Search PubMed⌕ Search

Biomedical subjects

J G Weg

Publications and source records attributed to J G Weg.

At least 19 recordsLinked to original sources
PubMed1998

The relation of pneumothorax and other air leaks to mortality in the acute respiratory distress syndrome.

BACKGROUND: In patients with the acute respiratory distress syndrome, pneumothorax and other air leaks - any extrusion of air outside the tracheobronchial tree - have been attributed to high ventilatory pressures or volumes and linked to increased mortality. METHODS: We analyzed data from a prospective trial of aerosolized synthetic surfactant in 725 patients with the acute respiratory distress syndrome induced by sepsis. We compared the ventilatory pressures and volumes in the patients without any air leaks (the highest values during the five-day study) with the pressures and volumes in those with pneumothorax or with any air leaks (the highest values during the 16- and 24-hour periods before the complication developed). RESULTS: Fifty patients (6.9 percent) had pneumothorax and 77 (10.6 percent) had pneumothorax or other air leaks. There were no significant differences between patients with air leaks and those without air leaks in any pressure or volume examined. Overall mortality at 30 days was 40.0 percent (95 percent confidence interval, 36.4 to 43.6); among the patients with pneumothorax, it was 46.0 percent (95 percent confidence interval, 32.2 to 59.8), and among those without pneumothorax, it was 39.3 percent (95 percent confidence interval, 35.6 to 43.0; P=0.35). The mortality rate was 45.5 percent (95 percent confidence interval, 34.4 to 56.6) in the group with any air leaks and 39.0 percent (95 percent confidence interval, 35.3 to 42.8) in the group without air leaks (P=0.28). CONCLUSIONS: In patients with sepsis-induced acute respiratory distress syndrome who were receiving mechanical ventilation with conventional pressures and volumes, there were no significant correlations between high ventilatory pressures or volumes and the development of pneumothorax or other air leaks. Pneumothorax or other air leaks were not associated with a significantly increased mortality rate.

Adult↗
PubMed1998

Long-term oxygen therapy for COPD. Improving longevity and quality of life in hypoxemic patients.

Long-term oxygen therapy can increase life expectancy in hypoxemic patients with COPD. Accurate identification of hypoxemia requires arterial blood gas measurements. Pulse oximetry can be used to measure trends in oxygenation, oxygen needs, and oxygen requirements during exercise and sleep. A detailed oxygen prescription indicates: (1) the oxygen dose (L/min), (2) the number of hours per day that oxygen therapy is required, (3) the dose required during exercise, (4) the oxygen supply system: concentrator, compressed gas cylinder, or liquid oxygen reservoir, and (5) the delivery device: nasal cannula, demand-flow device, reservoir cannula, or transtracheal oxygen catheter.

Humans↗
PubMed1997

Diagnosis of pulmonary embolism with magnetic resonance angiography.

BACKGROUND: Diagnosing pulmonary embolism may be difficult, because there is no reliable noninvasive imaging method. We compared a new noninvasive method, gadolinium-enhanced pulmonary magnetic resonance angiography, with standard pulmonary angiography for diagnosing pulmonary embolism. METHODS: A total of 30 consecutive patients with suspected pulmonary embolism underwent both standard pulmonary angiography and magnetic resonance angiography during the pulmonary arterial phase at the time of an intravenous bolus of gadolinium. All magnetic resonance images were reviewed for the presence or absence of pulmonary emboli by three independent reviewers who were unaware of the findings on standard angiograms. RESULTS: Pulmonary embolism was detected by standard pulmonary angiography in 8 of the 30 patients in whom pulmonary embolism was suspected. All 5 lobar emboli and 16 of 17 segmental emboli identified on standard angiograms were also identified on magnetic resonance images. Two of the three reviewers reported one false positive magnetic resonance angiogram each. As compared with standard pulmonary angiography, the three sets of readings had sensitivities of 100, 87, and 75 percent and specificities of 95, 100, and 95 percent, respectively. The interobserver correlation was good (k=0.57 to 0.83 for all vessels, 0.49 to 1.0 for main and lobar vessels, and 0.40 to 0.81 for segmental vessels). CONCLUSIONS: In this preliminary study, gadolinium-enhanced magnetic resonance angiography of the pulmonary arteries, as compared with conventional pulmonary angiography, had high sensitivity and specificity for the diagnosis of pulmonary embolism. This new technique shows promise as a noninvasive method of diagnosing pulmonary embolism without the need for ionizing radiation or iodinated contrast material.

Adult↗
PubMed1997

Lung volume reduction surgery alters management of pulmonary nodules in patients with severe COPD.

OBJECTIVE: To examine the role of lung volume reduction surgery (LVRS) in expanding the treatment options for patients with single pulmonary nodules and emphysema. METHODS: Retrospective review of all patients undergoing LVRS at the University of Michigan between January 1995 and June 1996. Those undergoing simultaneous LVRS and resection of a suspected pulmonary malignancy formed the study group and underwent history and physical examination, pulmonary function tests, chest radiography, and high-resolution CT of the chest. If heterogeneous emphysema was found, cardiac imaging and single-photon emission CT perfusion lung scanning were performed. All study patients participated in pulmonary rehabilitation preoperatively. Age- and sex-matched patients who had undergone standard lobectomy for removal of pulmonary malignancy during the same period formed the control group. RESULTS: Of 75 patients who underwent LVRS, 11 had simultaneous resection of a pulmonary nodule. In 10 patients, the nodules were radiographically apparent with 1 demonstrating central calcification. Histologic evaluation revealed six granulomas, two hamartomas, and three neoplastic lesions (one adenocarcinoma, one squamous cell, and one large cell carcinoma). Preoperative FEV1 was 26.18+/-2.49% predicted in the LVRS group and 81.36+/-6.07% predicted (p=0.000001) in the control group, and the FVC was 65.27+/-5.17% predicted vs 92.18+/-5.53% predicted (p=0.002). Two LVRS patients had a PaCO2 >45 mm Hg while 11 exhibited oxygen desaturation during a 6-min walk test. Postoperative complications occurred in two LVRS patients and three control patients. The mean length of stay in the LVRS group (7.55+/-1.10 days) was not different than in the control group (8.81+/-1.56 days). Three months after LVRS and simultaneous nodule resection, FEV1 rose by 47%, FVC by 25%, and all study patients noted less dyspnea as measured by transitional dyspnea index. CONCLUSIONS: Simultaneous LVRS and resection of a suspected bronchogenic carcinoma is feasible and associated with minimal morbidity and significantly improved pulmonary function and dyspnea.

Aged↗
PubMed1996

Aerosolized surfactant in adults with sepsis-induced acute respiratory distress syndrome. Exosurf Acute Respiratory Distress Syndrome Sepsis Study Group.

BACKGROUND: Patients with acute respiratory distress syndrome (ARDS) have a deficiency of surfactant. Surfactant replacement improves physiologic function in such patients, and preliminary data suggest that it may improve survival. METHODS: We conducted a prospective, multicenter, double-blind, randomized, placebo-controlled trial involving 725 patients with sepsis-induced ARDS. Patients were stratified according to the risk of death at base line (indicated by their score on the Acute Physiological and Chronic Health Evaluation [APACHE III] index) and randomly assigned to receive either continuously administered synthetic surfactant (13.5 mg of dipalmitoylphosphatidylcholine per milliliter, 364 patients) or placebo (o.45 percent saline; 361 patients) in aerosolized form for up to five days. RESULTS: The demographic and physiologic characteristics of the two treatment groups were similar at base line. The mean (+/- SD) age was 50 +/- 17 years in the surfactant group and 53 +/- 18 years in the placebo group, and the mean APACHE III scores at randomization were 70.4 +/- 25 and 70.5 +/- 25, respectively. Hemodynamic measures, measures of oxygenation, duration of mechanical ventilation, and length of stay in intensive care unit did not differ significantly in the two groups. Survival at 30 days was 60 percent for both groups. Survival was similar in the groups when analyzed according to APACHE III score, cause of death, time of onset and severity of ARDS, presence or absence of documented sepsis, underlying disease, whether or not there was a do-not-resuscitate order, and medical center. Increased secretions were significantly more frequent in the surfactant group; the rates of other complications were similar in the two groups. CONCLUSIONS: The continuous administration of aerosolized synthetic surfactant to patients with sepsis-induced ARDS had no significant effect on 30-day survival, length of stay in the intensive care unit, duration of mechanical ventilation, or physiologic function.

Administration, Inhalation↗
PubMed1996

Neuroendocrine responses to laboratory panic: cognitive intervention in the doxapram model.

Doxapram is a respiratory stimulant that appears to be a potent and specific panicogenic agent. It also elicits an abnormal ventilatory response in patients with panic. A replication study confirmed these findings and demonstrated that behavioral and ventilatory responses to doxapram were significantly modified by a psychological intervention designed to cognitively block panic. The replication study provided an opportunity to simultaneously investigate the neuroendocrine effects of the illness, the drug, the drug-induced panic attacks, and the cognitive intervention. Epinephrine (EPI), norepinephrine (NE), growth hormone (GH), adrenocorticotropin (ACTH), and cortisol were studied in patients with panic and control subjects given placebo and doxapram injections after receiving either standard instructions or a brief cognitive intervention. Patients with panic had elevated levels of EPI, ACTH, and cortisol throughout the study. Doxapram had little or no detectable effects on plasma NE, GH, ACTH, and cortisol. Doxapram-induced panic attacks were not associated with elevations in NE, GH, ACTH, or cortisol. Doxapram led to a rapid and very brief rise in plasma EPI, which was small in subjects who did not panic and pronounced in patients who did panic. The cognitive intervention attenuated the EPI response to doxapram, perhaps through its effect on panic, and modified the temporal pattern of ACTH and cortisol secretion. These results suggest that: (1) further study of catecholamine responses within the first few minutes after panic induction is needed; (2) intense panic can occur without significant activation of the hypothalamic-pituitary-adrenal axis; and (3) cognitive factors can modulate neuroendocrine activity in laboratory studies of patients with panic.

Acoustic Stimulation↗
PubMed1994

Safety and potential efficacy of an aerosolized surfactant in human sepsis-induced adult respiratory distress syndrome.

OBJECTIVE: To evaluate the safety and potential efficacy of aerosolized surfactant in intubated patients with adult respiratory distress syndrome (ARDS). DESIGN: A prospective, double-blind, placebo-controlled, randomized, parallel, multicenter pilot clinical trial. PATIENTS: A total of 51 patients with sepsis-induced ARDS were entered into the study within 18 hours of developing sepsis or sepsis syndrome. INTERVENTION: Patients were randomized into four treatment groups in a 2:1:2:1 ratio, as follows: 12 hours of surfactant per day, 12 hours of 0.6% saline per day, 24 hours of surfactant per day, and 24 hours of 0.6% saline per day. Surfactant or saline was aerosolized continuously for up to 5 days using an in-line nebulizer that aerosolized only during inspiration. MAIN OUTCOME MEASURES: Ventilatory data, arterial blood gases, and hemodynamic parameters were measured at baseline, every 4 or 8 hours during the 5 days of treatment, 24 hours after treatment, and 30 days after treatment, at which time mortality was also assessed. Safety was evaluated throughout the 30 days of the study. RESULTS: Surfactant was administered safely in ventilated patients when given continuously throughout the 5 days using the nebulizer system. Although there were no differences in any physiological parameters between the treatment groups, there was a dose-dependent trend in reduction of mortality from 47% in the combined placebo group to 41% and 35% in the groups treated with 12 hours and 24 hours of surfactant per day, respectively. CONCLUSIONS: Aerosolized surfactant was well tolerated when administered on a continuous basis for up to 5 days; however, at the doses given, it did not result in significant improvements in patients with sepsis-induced ARDS.

APACHE↗
PubMed1994

Aortobronchial fistula 13 years following repair of aortic transection.

We describe a 56-year-old man with the new onset of hemoptysis, increasing in frequency and magnitude, initially diagnosed and treated as pulmonary embolism. Bronchoscopy, computed tomography, and thoracic aortography were performed twice before the diagnosis was made. Thirteen years previously, the patient underwent thoracic aortic interposition graft placement for aortic laceration as a result of a motor vehicle accident. The second aortogram demonstrated a small pseudoaneurysm at the expected proximal graft suture line. Aortobronchial fistula, a rare cause of hemoptysis, was diagnosed. The patient underwent successful resection of the graft and placement of a new dacron interposition graft. All cultures, including blood, sputum, and operative specimen cultures, were negative. The patient is alive and well 1 year following surgery.

Aneurysm, False↗
PubMed1993

Effects of dense, high-volume, artificial surfactant aerosol on a heated exhalation filter system.

OBJECTIVE: To evaluate a supplemental heated filter system during mechanical ventilation with continuous nebulization of an artificial surfactant by a new, high-volume nebulizer. DESIGN AND METHODS: A new nebulizer system, containing artificial surfactant, provided half of a 20-L minute ventilation and the remainder of this minute ventilation was provided by a commonly used mechanical ventilator. Ventilation sources were joined in the inspiratory limb of the breathing circuit, which was connected to a test lung system. A supplemental filter system was placed upstream of the ventilator's heated filter in the expiratory limb of the circuit. Circuit pressures at the inlet of the supplemental filter (P1), between the filters (P2), and after the ventilator expiratory filter (P3) were monitored and recorded. Nebulizer canisters containing artificial surfactant were replaced every 4 hrs. The performance of four supplemental filters in continuous use was examined. Another four filters were each used over 4 hrs, steam autoclaved, and reused. SETTINGS: The ventilator was set at a rate of 20 breaths/min, with a tidal volume of 0.5 L, a flow rate of 40 L/min, and positive end-expiratory pressure of 10 cm H2O. The nebulizer provided an equal volume and flow rate so that the delivered tidal volume was 1.0 L with a flow rate of 80 L/min. RESULTS: Ventilator failure and/or excessive airway pressure caused by increased filter resistance occurred at a mean of 7.3 +/- 1.3 (SD) hrs of continuous ventilation. Mean P1-peak increased from 67.5 +/- 8.2 to 94.0 +/- 10.7 cm H2O (p < .001) and P1-baseline increased from 9.3 +/- 1.0 to 53.5 +/- 17.1 cm H2O (p = .014). Filters that were autoclaved after 4 hrs of ventilation and reused lasted a total of 7.0 +/- 1.3 hrs. Mean P1-peak increased from 68.9 +/- 4.9 to 84.8 +/- 19.1 cm H2O and P1-baseline increased from 9.5 +/- 1.7 to 30.8 +/- 14.2 cm H2O (p < .05). CONCLUSIONS: The supplemental filter system was able to protect the ventilatory exhalation sensors for approximately 7 hrs at a minute ventilation of 20 L/min. Steam sterilization did not extend the supplemental filter life.

Aerosols↗