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Biomedical subjects

G W Soo Hoo

Publications and source records attributed to G W Soo Hoo.

7 recordsLinked to original sources
PubMed1996

Fluorodeoxyglucose-positron emission tomography in the detection and staging of lung cancer.

Glycolysis is increased in tumor tissues. [18F]fluoro-2-deoxy-D-glucose (FDG) is a glucose analogue radiopharmaceutical used in positron emission tomography (PET) to trace glucose metabolism. We investigated the sensitivity and specificity of FDG-PET imaging in the diagnosis and staging of lung cancer. One hundred and seven patients who had abnormal chest roentgenograms underwent whole-body PET imaging using FDG. PET scan results were classified as positive or negative based on the presence or absence of increased FDG uptake in the lung and/or in the mediastinum. All 82 patients with lung cancer had increased FDG uptake in the lungs, whereas only 12 of 25 patients with nonmalignant diseases had increased FDG uptake. Sixteen lung cancer patients with mediastinal metastases had increased FDG uptake in the mediastinum, of whom three had no lymphadenopathy on computed tomography of the chest. Sixteen lung cancer patients without mediastinal nodal involvement had no FDG uptake in the mediastinum. Seven of these patients had lymphadenopathy on computed tomography. FDG-PET imaging is 100% accurate in predicting mediastinal involvement in patients with lung cancer. It is 100% sensitive and 52% specific in predicting the malignant nature of a chest radiographic abnormality.

Adenocarcinoma↗
PubMed1994

Nasal mechanical ventilation for hypercapnic respiratory failure in chronic obstructive pulmonary disease: determinants of success and failure.

OBJECTIVES: To evaluate the efficacy of nasal mechanical ventilation in patients with chronic obstructive pulmonary disease and hypercapnic respiratory failure and to identify predictors of success or failure of nasal mechanical ventilation. DESIGN: Prospective case series. SETTING: Medical intensive care unit in Veterans Administration Medical Center. PATIENTS: Twelve chronic obstructive pulmonary disease patients treated during 14 episodes of hypercapnic respiratory failure. INTERVENTIONS: Nasal mechanical ventilation in addition to conventional therapy to treat hypercapnic respiratory failure. Patients underwent nasal mechanical ventilation for at least 30 mins, or longer if the therapy was tolerated. Responses to therapy and arterial blood gases were monitored. MEASUREMENTS AND MAIN RESULTS: Half of the episodes were successfully treated with nasal mechanical ventilation. There were no differences in age, prior pulmonary function, baseline arterial blood gases, admission arterial blood gases, or respiratory rate between those patients successfully treated and those patients who failed nasal mechanical ventilation. Unsuccessfully treated patients appeared to have a greater severity of illness than successfully treated patients, as indicated by a higher Acute Physiology and Chronic Health Evaluation II score (mean 21 +/- 4 [SD] vs. 15 +/- 4; p = .02). Unsuccessfully treated patients were edentulous, had pneumonia or excess secretions, and had pursed-lip breathing, factors that prevented adequate mouth seal and contributed to greater mouth leaks than in successfully treated patients (the mean volume of the mouth leak was 314 +/- 107 vs. 100 +/- 70 mL; p < .01). Successfully treated patients were able to adapt more rapidly to the nasal mask and ventilator, with greater and more rapid reduction in PaCO2, correction of pH, and reduction in respiratory rate. CONCLUSIONS: Patients who failed nasal mechanical ventilation appeared to have a greater severity of illness; they were unable to minimize the amount of mouth leak (because of lack of teeth, secretions, or breathing pattern) and were unable to coordinate with the ventilator. These features may allow identification of poor candidates for nasal mechanical ventilation, avoiding unnecessary delays in endotracheal intubation and mechanical ventilation.

Acute Disease↗
PubMed1990

Inhaled or intravenous pentamidine therapy for Pneumocystis carinii pneumonia in AIDS. A randomized trial.

OBJECTIVE: To compare inhaled pentamidine with intravenous pentamidine for the treatment of Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome (AIDS). DESIGN: A randomized trial. SETTING: Community teaching hospital and hospital-based outpatient treatment center. PATIENTS: Twenty-one homosexual men with pneumocystis pneumonia; 11 received inhaled pentamidine and 10 received intravenous pentamidine. INTERVENTION: Inhaled (8 mg/kg body weight) or intravenous (4 mg/kg body weight) pentamidine administered daily for 21 days. MEASUREMENTS AND MAIN RESULTS: All patients responded to intravenous pentamidine, whereas 6 of 11 (55%; 95% CI, 23% to 83%; P = 0.02, Fisher exact test) responded to inhaled pentamidine therapy. Two patients who failed inhaled pentamidine therapy eventually died despite appropriate intravenous therapy (mortality rate, 18%; CI, -6% to 42%). Nonresponders to inhaled pentamidine had a greater severity of illness compared with responders to this therapy, as shown by a lower mean (+/- SE) Pao2 (8.0 +/- 0.4 kPa compared with 10.8 +/- 0.6 kPa; P = 0.005) and higher alveolararterial Po2 difference (6.8 +/- 0.6 kPa compared with 2.8 +/- 0.8 kPa; P = 0.003). CONCLUSIONS: Inhaled pentamidine is probably as effective as intravenous pentamidine in patients with mild pneumocystis pneumonia. However, its use as sole therapy in patients with moderate to severe pneumocystis pneumonia is not supported by the results of our study and is not warranted.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Improvement in exercise performance after pulmonary arteriovenous malformation embolization.

Balloon or coil embolization has become established therapy for multiple PAVMs. We were able to evaluate a 32-year-old woman with multiple PAVMs characterized by significant orthodeoxia, intrapulmonary shunt, dyspnea and limited exercise tolerance before and after balloon and coil embolization. After embolization of three of her largest PAVMs, repeat evaluation revealed improvement in her symptoms, orthodeoxia and intrapulmonary shunt. She was able to exercise two additional work rates with a sustained improvement in oxygenation, a decrease in the P(A-a)O2 difference and higher maximum oxygen consumption. These studies provide objective evidence of persistent improvement in function and endurance at rest and during exercise after embolization.

Adult↗
PubMed1990

Efficacy of positive vs negative pressure ventilation in unloading the respiratory muscles.

We compared the efficacy of positive pressure ventilation (PPV) vs negative pressure ventilation (NPV) in providing ventilatory muscle rest for five normal subjects and six patients with chronic obstructive pulmonary disease (COPD). All participants underwent measurement of transdiaphragmatic pressure (Pdi), pressure time integral of the diaphragm (PTI), integrated diaphragmatic electromyogram (iEMG), minute ventilation (Ve), tidal volume (Vt), and end-tidal CO2 (etCO2) during 15 minutes of PPV and NPV. For each subject, ventilator adjustments were made to obtain Ve similar to levels measured during quiet breathing (QB). We found that the iEMG, Pdi, PTI, and average coefficient of variation of the tidal volume (CV-Vt) were consistently lower during PPV as compared with NPV (p = 0.01). The iEMG normalized for Ve and Vt was also significantly lower during PPV (p = 0.01). During PPV, subjects were mildly hyperventilated (lower etCO2 and higher Ve) compared with QB and NPV, but no significant correlation was noted between the change in etCO2 and the change in iEMG. The change in PTI was significantly correlated with the change in iEMG (p less than 0.01). We conclude that in the short term, PPV is more effective than NPV in reducing diaphragmatic activity. Positive pressure ventilation may be the preferred method of assisted ventilation in future studies of ventilatory muscle rest therapy.

Aged↗
PubMed1984

Reducing tuberculosis detection costs.

Use of sputum culture for diagnosis of tuberculosis is an inefficient detection technique in a disease of declining prevalence. We found such testing at our 400 bed acute care hospital resulted in less than 2 percent positive when done with prior patient screening. In an effort to minimize detection costs, restrictions requiring that a tuberculin skin test and chest roentgenogram be performed prior to processing the MTB culture were instituted. This resulted in 672 fewer cultures being processed in the trial year, a significant (44 percent) reduction compared to the prior year. At $50.00 per culture, this represents an annual savings of more than $30,000.

Cytological Techniques↗