Resuscitation and trauma.
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Blast Injuries↗
Biomedical subjects
T D Miller
Publications and source records attributed to T D Miller.
A comparative study of atropine sulfate and isoproterenol hydrochloride in chronic bronchitis.
Fifteen subjects with chronic bronchitis were treated with inhaled atropine sulfate, isoproterenol hydrochloride, or placebo in a double blind crossover trial. Each drug was inhaled 4 times per day for 3 weeks. Baseline forced expiratory flows, specific airway conductance, airway resistnace, and functional residual capacity were measured weekly. These measurements were repeated 15 min and 60 min after laboratory inhalation of each agent, using a separate double blind protocol. No significant differences were observed among the mean baseline function studies during the 3 treatment periods. There were no significant differences in sputum production, sputum thickness, dyspnea, or mouth dryness among the 3 treatment periods. Side effects were mild; isoproterenol treatment was associated with an increased frequency of palpitations, and atropine treatment was associated with difficulty in voiding. Significant increases in lung function were apparent in the measurements made 15 min and 60 min after inhalation of atropine or isoproterenol. Mean values of flow and specific airway conductance increased, and mean values of airway resistance and functional residual capacity decreased after inhalation of either drug. There was no significant difference between the effects of atropine and isoproterenol on lung function, although both differed significantly from the effects of placebo (P less than 0.001). Inhaled atropine sulfate was as effective a bronchodilator as inhaled isoproterenol hydrochloride, and was well tolerated during the 3-week trial of daily therapy.
Adult↗
An estimate of the prevalence of reversible left ventricular dysfunction in patients referred for coronary artery bypass surgery.
BACKGROUND: The prevalence of reversible left ventricular function through revascularization has been difficult to assess because of the referral bias inherent in patients undergoing viability-targeted preoperative testing. METHODS AND RESULTS: Rest and exercise gated equilibrium radionuclide angiography was performed in 86 patients within 6 months before and any time after coronary artery bypass. Clinical characteristics were recorded for each patient before each of the two radionuclide ventriculograms. Global left ventricular ejection fraction (LVEF) was calculated for each patient at rest. A definite change in LVEF was defined as 0.08 or more points and a probable change as 0.04 or more points. Only patients with a resting LVEF of 0.50 or less were eligible for the study. There was no significant group change in LVEF (0.39 +/- 0.08 before surgery vs 0.38 +/- 0.11 after surgery; difference not significant). However, a definite improvement in LVEF was seen in 18 patients (21%) and a probable change in an additional 10 (12%). Consequently, one third of the patients had at least a probable improvement in resting left ventricular function. These prevalences were not related to any change in medical therapy. CONCLUSION: According to a test not specifically designed to evaluate myocardial viability, the prevalence of reversible left ventricular dysfunction is not uncommon, occurring in up to one third of patients referred for coronary revascularization.
Confounding Factors, Epidemiologic↗
Prognosis in patients with spontaneous chest pain, a nondiagnostic electrocardiogram, normal cardiac enzymes, and no evidence of severe resting ischemia by quantitative technetium 99m sestamibi tomographic imaging.
BACKGROUND: There are limited data addressing the outcome of patients with normal or near normal myocardial perfusion during chest pain at rest. The purpose of this study was to determine the prognosis of patients with spontaneous chest pain, a normal or nondiagnostic electrocardiogram, no enzymatic evidence of myocardial infarction, and no evidence of severe resting ischemia by quantitative technetium 99m (99mTc) sestamibi imaging. METHODS: In the study, 111 patients who fulfilled the above criteria were injected with 99mTc sestamibi during resting chest pain and were followed for a median 2.7 years. Of the patients in the study group, 58% had coronary artery disease that was documented by clinical history or coronary angiography. Tomographic 99mTc perfusion images were interpreted with a quantitative threshold technique initially developed to detect severely hypoperfused myocardium. The images were also interpreted qualitatively to detect patients with milder degrees of hypoperfused myocardium. RESULTS: During follow-up 3 patients had cardiac deaths, 5 had nonfatal myocardial infarctions, and 21 underwent revascularization procedures (13 within 3 months and 8 more than 3 months after the sestamibi study). At 3 years, survival free of cardiac death was 97%, survival free of cardiac death or myocardial infarction was 91%, and survival of cardiac death, myocardial infarction, or late revascularization was 82%. Quantitative analysis of the scans revealed that 100% of patients without fixed defects had 3-year survival free of cardiac death versus 76% of patients who had fixed defects (p < 0.001). Mild to moderate resting ischemia by qualitative interpretation of the scans was present in 20% of patients, but this did not predict outcome. CONCLUSIONS: Patients with spontaneous chest pain and nonischemic quantitative 99mTc sestamibi images were at reasonably low risk for hard cardiac events although some patients (18%) required revascularization.
Aged↗
Prediction of severe coronary artery disease and long-term outcome in patients undergoing vasodilator SPECT.
BACKGROUND: Vasodilator perfusion imaging has not been extensively evaluated for predicting severe coronary artery disease (CAD) or long-term prognosis. METHODS AND RESULTS: The goals of this study were to develop a model to predict left main/3-vessel CAD in patients undergoing vasodilator thallium 201 imaging and coronary angiography (angiographic population) and to test the long-term prognostic value of this model in a separate cohort of patients who were not referred for angiography (prognostic population). In the angiographic population (n = 653) the chi2 value of the clinical model (containing the variables age, sex, and prior myocardial infarction) in the prediction of severe CAD was 32. The addition of 3 vasodilator Tl-201 variables (magnitude of ST-segment depression, summed reversibility score, and increased lung uptake) increased the model chi2 value to 114 (P <.001). Only 9% of predicted low-risk patients versus 57% of predicted high-risk patients had severe CAD. In the prognostic population (n = 521) survival rates free of cardiac death or myocardial infarction at 7 years were 91%, 73%, and 51%, respectively, for patient groups predicted to be at low, intermediate, and high risk of severe CAD (P <.001). CONCLUSIONS: Clinical and vasodilator Tl-201 variables can accurately predict the risk of severe CAD. Stress Tl-201 variables add incremental information to clinical variables. The same model also predicts patient outcome.
Adenosine↗
Infarct size measured by single photon emission computed tomographic imaging with (99m)Tc-sestamibi: A measure of the efficacy of therapy in acute myocardial infarction.
BACKGROUND: Use of mortality as an end point in randomized trials of reperfusion therapy requires increasingly large sample sizes to test advances compared with existing therapy, which is already highly effective. There has been a growing interest in infarct size measurements by (99m)Tc-sestamibi SPECT (single photon emission computed tomographic) imaging as a surrogate end point. METHODS AND RESULTS: We reviewed the reports published in English regarding infarct size measurements by (99m)Tc-sestamibi. Four separate lines of published evidence support the validity of SPECT imaging with (99m)Tc-sestamibi for determination of infarct size. This end point has been used in a total of 7 randomized trials-1 single center and 6 multicenter. The end point compares favorably with left ventricular function and infarct size measurements with the use of other radiopharmaceuticals. The most important limitation of this approach is the absence thus far of a randomized trial that has shown a corresponding decrease in mortality in association with a therapy that reduces infarct size. CONCLUSIONS: SPECT imaging with (99m)Tc-sestamibi is the best available measurement tool for infarct size. It has already served as an end point in early pilot studies to evaluate potential efficacy and in dose-ranging studies. It has the potential to serve as a surrogate end point to uncover advantages of new therapies that may be equivalent to existing therapies with respect to early mortality.
Heart↗
Prognostic value of treadmill exercise testing: a population-based study in Olmsted County, Minnesota.
BACKGROUND: The prognostic value of treadmill exercise testing (TMET) has been studied in selected populations. The generalizability of these data to different populations and to women is uncertain. METHODS AND RESULTS: A retrospective, population-based cohort study of all persons (1452 men and 741 women) who underwent TMET in years 1987 to 1989 in Olmsted County, Minnesota, was undertaken. Individuals were followed up for all-cause mortality and cardiac events (cardiac deaths, nonfatal myocardial infarction, or congestive heart failure). Sex-specific analyses were performed to determine whether the predictors of outcome and the magnitude of the associations were similar in both sexes. In men, 77 deaths and 106 cardiac events occurred during 8956 person-years of observation; in women, 46 deaths and 54 cardiac events occurred during 4801 person-years of follow-up. Exercise-induced angina, ECG changes, and workload achieved on the TMET were strongly associated with all-cause mortality and cardiac events in both sexes, and the strength of the association was similar. After adjustment, workload was the only TMET variable associated with outcome. A higher workload was associated with a reduction in the risk of cardiac events and of all-cause mortality; the protective effect of exercise capacity was strong and was similar in both sexes. CONCLUSIONS: In this population-based cohort, exercise capacity was the TMET variable that exhibited the strongest association with all-cause mortality and cardiac events. This protective effect of exercise capacity was observed in both sexes.
Aged↗
Isolation of Pacheco's disease herpesvirus in Texas.
Pacheco's disease herpesvirus was determined to be the agent responsible for the death of about 200 psittacine birds comprising five species. Clinical signs, necropsy lesions, and virus isolation and identification methods are described.
Animals↗