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Biomedical subjects

J Loke

Publications and source records attributed to J Loke.

11 recordsLinked to original sources
PubMed1992

Lung function in fire fighters.

Lung function tests were performed on 49 fire fighters of the city of New Haven. Their mean age was 36.4 years, with a mean of 11.7 years as fire fighters. The lung function tests were compared to a control group with a mean age of 33.4 years. There was no significant difference between the mean normal pulmonary function tests of the fire fighters and the control group. The results showed that in this group of fire fighters long-term occupational exposure was not associated with pulmonary function abnormalities.

Adolescent↗
PubMed1989

The pulmonary function laboratory.

The pulmonary function laboratory is essential for evaluating patients with respiratory complaints and disorders. Lung function tests are widely used to detect evidence of disease, quantitate severity of dysfunction, elucidate pathophysiologic mechanisms, and assess response to therapy. For these reasons, standards for personnel, infection control and safety, equipment, and quality control are important considerations for the generation of physiologic data.

Humans↗
PubMed1988

Terbutaline and diaphragm function in chronic obstructive pulmonary disease: a double-blind randomized clinical trial.

We conducted a double-blind, randomized crossover trial to evaluate whether oral terbutaline (2.5 mg orally three times daily for a week) increased the force of diaphragmatic contraction in normocapnic patients with chronic obstructive pulmonary disease. Ten patients with moderate to severe airway obstruction completed the trail. Compared with placebo, terbutaline produced a mean increase of 5.8 cmH2O in peak inspiratory mouth pressure and a mean increase of 5.0 cmH2O in transdiaphragmatic pressure during a maximal inspiratory manoeuvre. These small changes with terbutaline failed to achieve statistical significance. Also, terbutaline failed to alter flow rates (FEV1, Vmax50) or patients' dyspnoea ratings using two separate clinical scales (Pneumoconiosis Research Unit Score and the Modified Dyspnoea Index). Because all observed changes in respiratory muscle strength were small and because the trial had power to detect small changes in inspiratory mouth pressures, we suggest that oral terbutaline at the dose administered in this study has little noteworthy effect on respiratory muscle strength in normocapnic patients with chronic obstructive pulmonary disease.

Aged↗
PubMed1988

Oral terbutaline augments cardiac performance in chronic obstructive pulmonary disease.

In previous research, we have demonstrated that parenterally administered terbutaline can augment resting cardiac function in patients with chronic obstructive pulmonary disease (COPD). Because the oral form of terbutaline is more widely utilized, a double-blind, randomized, crossover, placebo-controlled trial of the cardiopulmonary effects of oral terbutaline was conducted in ten patients with COPD. Right and left ventricular ejection fractions (RVEF and LVEF) were determined by first pass radionuclide angiography. There were no differences in spirometry and hemodynamic measurements between treatment and placebo days. Following 5 mg of oral terbutaline, there was a small but statistically significant increase in forced expiratory volume in 1 second and in heart rate, but no significant change in forced vital capacity or blood pressure. LVEF improved significantly with terbutaline both at rest (62% +/- 6% vs. 67% +/- 9%, mean +/- SD) and during submaximal steady state exercise (61% +/- 5% vs. 67% +/- 10%). RVEF improved significantly at rest (64% +/- 6% vs. 69% +/- 5%), but not during submaximal steady state exercise (65% +/- 6% vs. 68% +/- 7%). Thus, oral terbutaline produces significant improvement in biventricular systolic pump performance at rest, and increases left ventricular ejection fraction during submaximal exercise in patients with moderate to severe COPD.

Administration, Oral↗
PubMed1988

Bilateral diaphragmatic paralysis: clinical spectrum, prognosis, and diagnostic approach.

In a retrospective review of the clinical course of five patients with nontrauma-related bilateral diaphragmatic paralysis, we found that the diagnosis is generally delayed (median delay: two years) in the presence of moderate to severe respiratory insufficiencies. Orthopnea out of proportion to the underlying cardiopulmonary status and thoracoabdominal paradoxus in the supine position are the clues to the diagnosis. Pulmonary function tests showed a typical restrictive ventilatory defect, and arterial blood gas showed chronic respiratory acidosis. Failure to recognize the diaphragmatic impairment led to cardiopulmonary decompensations such as cor pulmonale and acute respiratory failure. However, with the institution of appropriate therapy, adverse effects resolved and all five patients are alive and continue to lead independent lives. We conclude that nontrauma-related bilateral diaphragmatic paralysis is an underrecognized and underdiagnosed condition. The results also indicate that early diagnosis and treatment can minimize morbidity and mortality, and that excellent long-term, good-quality survival can be expected.

Aged↗
PubMed1986

Carbon dioxide sensitivity in panic anxiety. Ventilatory and anxiogenic response to carbon dioxide in healthy subjects and patients with panic anxiety before and after alprazolam treatment.

One hypothesis that could account for the anxiogenic response to breathing air supplemented with carbon dioxide seen in panic anxiety patients is that panic patients might have abnormally high central medullary chemoreceptor sensitivity. Chemoreceptor sensitivity was assessed by using a rebreathing technique to measure the ventilatory response to CO2 in 14 medication-free patients with agoraphobia and panic attacks and 23 healthy subjects. Ventilatory response to CO2 was similar in patients and controls (mean +/- SEM, 1.58 +/- 0.16 vs 1.58 +/- 0.14 L/min/mm Hg), suggesting that abnormal chemoreceptor sensitivity does not explain the behavioral sensitivity of panic patients to CO2. Anxiety ratings increased markedly during rebreathing both in patients and controls; anxiety increases were significantly greater in patients than in healthy subjects matched for age, sex, and rebreathing duration. Alprazolam treatment in eight patients markedly attenuated anxiety increases during rebreathing. Differences in anxiogenic sensitivity to CO2 between patients and controls may be due to differences in the regulation of noradrenergic or other neuronal systems.

Adult↗
PubMed1978

Assessment of cardiac performance with quantitative radionuclide angiocardiography: right ventricular ejection fraction with reference to findings in chronic obstructive pulmonary disease.

A reproducible noninvasive technique for measuring righ ventricular ejection fraction was developed using first pass quantitative radionuclide angiocardiography. Studies were obtained in the anterior position with a computerized multicrystal scintillation camera with high count rate capabilities. Right ventricular ejection fraction was calculated on a beat to beat basis from the high frequency components of the background-corrected right ventricular time-activity curve. In 50 normal adults, right ventricular ejection fraction averaged 55 percent (range of 45 to 65 percent). This radionuclide measure of right ventricular function was reproducible, with minimal inter- and intraobserver variability, and was sensitive to changes in inotropic state induced with isoproterenol. In 36 patients with chronic obstructive pulmonary disease, right ventricular ejection fraction ranged from 19 to 71 percent. All 10 patients with corpulmonale, as well as 9 additional patients, had an abnormal right ventricular ejection fraction. Arterial oxygen tension and forced expiratory volume were depressed significantly more in patients with abnormal right ventricular ejection fraction than in subjects with normal right ventricular function. There was no relation between abnormalities in right and left ventricular ejection fraction.

Adult↗
PubMed1977

Radiographic manifestations of acute smoke inhalation.

Acute smoke inhalation may lead to serious pulmonary injury and contribute significantly to mortality of fire victims. The chest radiographic findings in 21 patients with acute smoke inhalation are analyzed, and possible pathophysiologic mechanisms responsible for the radiographic abnormalities noted are discussed. Patients with surface injury burns were intentionally eliminated from this study. Our findings indicate that the standard chest radiograph is an insensitive means of determining pulmonary injury by smoke inhalation. The importance of blood carboxyhemoglobin levels and arterial blood gas determinations in the clinical evaluation of patients with acute smoke inhalation is stressed.

Acute Disease↗
PubMedDate not supplied

Systemic and discoid lupus erythematosus: analysis of pulmonary function.

To determine the prevalence of pulmonary dysfunction in lupus erythematosus, 24 patients with systemic lupus erythematosus (SLE) and 5 patients with discoid lupus erythematosus (DLE) were studied. Diffusing capacity for carbon monoxide was abnormal in 17 (71 percent) SLE patients. A restrictive ventilatory defect was present in 6 (25 percent) and arterial hypoxemia in 4 of 23 (17 percent). The mean ratio of forced expiratory volume in one second to forced vital capacity (FVC) was 83 percent. To test for the presence of small airways disease, maximum expiratory flow rate at 50 percent of FVC was measured on air and on an 80 percent helium-20 percent oxygen mixture. Ten patients (5 smokers and 5 nonsmokers) with SLE were nonresponders to helium suggesting small airways disease. Pulmonary dysfunction was present in 90 percent (9/10) of SLE patients with a previous history of pleuritis and/or pneumonitis, and in 71 percent (10/14) without respiratory symptoms or history of lung disease and with a normal chest radiograph. Pulmonary function tests were normal in DLE patients except for an abnormal response to helium and/or mild arterial hypoxemia in two patients, all of whom were smokers. These data indicate that there is a high prevalence of pulmonary function abnormalities in SLE including patients without clinically evident pleuropulmonary disease.

Female↗