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Biomedical subjects

H S Miller

Publications and source records attributed to H S Miller.

At least 19 recordsLinked to original sources
PubMed2000

A multicenter controlled trial of fetal pulse oximetry in the intrapartum management of nonreassuring fetal heart rate patterns.

OBJECTIVE: Recent developments permit the use of pulse oximetry to evaluate fetal oxygenation in labor. We tested the hypothesis that the addition of fetal pulse oximetry in the evaluation of abnormal fetal heart rate patterns in labor improves the accuracy of fetal assessment and allows safe reduction of cesarean deliveries performed because of nonreassuring fetal status. STUDY DESIGN: A randomized, controlled trial was conducted concurrently in 9 centers. The patients had term pregnancies and were in active labor when abnormal fetal heart rate patterns developed. The patients were randomized to electronic fetal heart rate monitoring alone (control group) or to the combination of electronic fetal monitoring and continuous fetal pulse oximetry (study group). The primary outcome was a reduction in cesarean deliveries for nonreassuring fetal status as a measure of improved accuracy of assessment of fetal oxygenation. RESULTS: A total of 1010 patients were randomized, 502 to the control group and 508 to the study group. There was a reduction of >50% in the number of cesarean deliveries performed because of nonreassuring fetal status in the study group (study, 4. 5%; vs. control, 10.2%; P =.007). However, there was no net difference in overall cesarean delivery rates (study, n = 147 [29%]; vs. control, 130 [26%]; P = .49) because of an increase in cesarean deliveries performed because of dystocia in the study group. In a blinded partogram analysis 89% of the study patients and 91% of the control patients who had a cesarean delivery because of dystocia met defined criteria for actual dystocia. There was no difference between the 2 groups in adverse maternal or neonatal outcomes. In terms of the operative intervention for nonreassuring fetal status, there was an improvement in both the sensitivity and the specificity for the study group compared with the control group for the end points of metabolic acidosis and need for resuscitation. CONCLUSION: The study confirmed its primary hypothesis of a safe reduction in cesarean deliveries performed because of nonreassuring fetal status. However, the addition of fetal pulse oximetry did not result in an overall reduction in cesarean deliveries. The increase in cesarean deliveries because of dystocia in the study group did appear to result from a well-documented arrest of labor. Fetal pulse oximetry improved the obstetrician's ability to more appropriately intervene by cesarean or operative vaginal delivery for fetuses who were actually depressed and acidotic. The unexpected increase in operative delivery for dystocia in the study group is of concern and remains to be explained.

Adult↗
PubMed1998

Vernix caseosa peritonitis: report of two cases with antenatal onset.

Maternal peritonitis secondary to fetal vernix caseosa is considered an infrequent complication of cesarean section in which commonly spilled amniotic fluid is incompletely lavaged. Nine of the 10 reported cases have been diagnosed in the postpartum period after an uneventful cesarean section. Characteristically, vernix elicits granulomatous inflammation, occasionally with a mass lesion simulating bowel perforation and leading to colectomy. One case of antenatal leakage of amniotic fluid has been reported, also with granulomatous inflammation. We report two additional cases of antenatal leakage, both with acute inflammation lacking granulomatous features or mass lesions. The interval between amniotic fluid contamination and histopathologic evaluation is the basis for variations in the inflammatory pattern.

Adult↗
PubMed1997

Effects of cardioselective beta blockers on ventilation and gas exchange in patients with heart disease during ramp treadmill testing.

The effects of cardioselective beta blockade on ventilation and gas exchange were investigated in 12 male subjects with coronary artery disease during ramp treadmill testing. Patients were able to maintain much of their functional capacity as measured by oxygen consumption in the beta-blocked condition, and also maintained minute ventilation by increasing respiratory rate despite a decrease in tidal volume.

Adrenergic beta-Antagonists↗
PubMed1997

Identification of the anaerobic threshold using double product in patients with coronary artery disease.

This study compared the ventilatory threshold with the double-product break point in 104 patients with cardiovascular disease during ramp treadmill testing. The high correlation (r = 0.81) between the double-product break point and the ventilatory threshold, even in patients taking beta blockers, suggests the former method is a viable noninvasive alternative for identifying the anaerobic threshold in patients with cardiovascular disease, particularly when expired gas analysis is not appropriate or available.

Adrenergic beta-Antagonists↗
PubMed1996

Comparison of standard- and extended-length participation in cardiac rehabilitation on body composition, functional capacity, and blood lipids.

Participation in a standard-length outpatient cardiac rehabilitation program (CRP) for 3 months is known to result in positive changes in body composition, functional capacity, and blood lipids in patients with coronary artery disease. However, there has been little attempt to compare patients who remain active in a formal CRP for an extended length of >1 year with patients who exit after a standard length of 3 months. Consequently, 50 patients underwent a series of tests including a maximal graded exercise treadmill test, assessment of body composition, and fasting blood lipid analysis, at entry to CRP and after a follow-up period that ranged from 1 to 5 years. All patients participated in a standard multidisciplinary cardiac rehabilitation program for 3 months. Twenty-five patients discontinued participation after 3 months and received no other contact from the program staff until follow-up, whereas 25 patients remained active in the program until follow-up. After statistically adjusting for baseline differences between the groups, significant differences were observed between the extended- and standard-length groups at follow-up for body weight (177 vs 183 lbs), percent fat (22% vs 24%), METS (10.5 vs 8.4), high-density lipoprotein level cholesterol (44 vs 39 mg/dl), total cholesterol/high-density lipoprotein ratio (5.2 vs 6.1), and triglycerides (134 vs 204 mg/dl), respectively. No significant differences in the adjusted means were observed between the groups at follow-up for total cholesterol (209 vs 219 mg/dl) and low-density lipoprotein cholesterol (136 vs 138 mg/dl). Data from this study demonstrate the efficacy of extended participation in CRP on body composition, functional capacity, and blood lipids. Greater efforts need to be directed at retaining patients in low-cost, center-based maintenance programs and at extending monitoring of patients exiting standard length CRPs.

Adult↗
PubMed1996

Adolescence and very low birth weight infants: a disproportionate association.

OBJECTIVE: To examine the incidence of very low birth weight (VLBW) neonates, defined as those weighing less than 1500 g, delivered by adolescents compared with the general obstetric population. METHODS: A retrospective observational study of 16,857 women delivering live-born infants from January 1, 1989, to June 30, 1993, was conducted at the University of Arizona Health Sciences Center. Adolescents were defined as those having a maternal age of 18 years or less at the time of delivery. The rate of VLBW infants delivered to adolescent mothers was compared with the general obstetric population (women at least 19 years old) using chi 2 analysis, multiple analysis of variance, and multiple linear regression. RESULTS: During the study period, 204 VLBW infants were delivered, yielding an overall VLBW delivery rate of 1.2%. Adolescents had a VLBW delivery rate that was considerably higher than the general obstetrical population: 35 of 1758 (2.0%) versus 169 of 15,099 (1.1%) (P = .002). Whereas adolescents accounted for 10.6% of the total deliveries during the study period, they delivered 17% of the VLBW neonates. The relative risk of an adolescent delivering a VLBW infant was 1.7 (95% confidence interval 1.2-2.2). CONCLUSION: Preterm birth is one of the major unresolved problems in modern obstetrics. Although the association between adolescence and preterm birth has been reported previously, specific attention has not been focused on the VLBW neonate. We conclude that adolescents deliver a disproportionate number of VLBW infants.

Adolescent↗
PubMed1996

Effect of intrapartum use of oxytocin on estimated blood loss and hematocrit change at vaginal delivery.

We hypothesized that exogenous oxytocin given for labor induction or augmentation results in a greater blood loss at vaginal delivery compared with spontaneous labor. Second, we theorized that duration of exposure, and maximum or final dosage of oxytocin, would be positively correlated with blood loss. We retrospectively studied records of 111 women undergoing labor induction or augmentation by oxytocin infusion along with those of 76 women who had spontaneous labor. The outcomes evaluated included clinically estimated blood loss (EBL), and a change of hematocrit from admission to postpartum. These were further compared to duration and dosage of oxytocin infused. A combination of chi-square and analysis of variance were used to compare the study group with the controls. Regression analysis was used to evaluate possible relationships within the study group. The demographics of the study group who received oxytocin were similar to those of the control group, with the exception of the percent who received an epidural (77% versus 29%, p < 0.0001) and length of labor (381 versus 277 min, p < 0.001). There was no demonstrated relationship between oxytocin use and EBL or hematocrit change. Within the study group of 111 patients, there was a statistically significant increase in EBL (p < 0.01) and hematocrit change (p < 0.0003) with increasing maximum dose of oxytocin. In addition, hematocrit change was greater with an increase in both duration (p < 0.001) and final dose of oxytocin (p < 0.0003). No relationship was demonstrated between exogenous oxytocin administration and increased blood loss, in a group of patients matched for variables other than spontaneous or oxytocin exposed labors. However, among those patients who received oxytocin, there was a correlation between amount of oxytocin exposure and blood loss. The initial hypothesis compared means between the two groups; however, the latter hypothesis sought to correlate increased exposure to oxytocin with increasing blood loss as measured by duration, maximum, and final dose.

Adult↗
PubMed1996

Estimation of VO2 in older individuals with osteoarthritis of the knee and cardiovascular disease.

The American College of Sports Medicine (ACSM) equation for estimating oxygen consumption (VO2) is often inappropriately applied to non-steady-state treadmill exercise. Therefore, it was the purpose of this investigation to develop an equation to estimate VO2 that could be applied to non-steady-state treadmill exercise in a population of patients with osteoarthritis of the knee, and to assess the generalizability of this equation for estimating VO2peak in patients with cardiovascular disease. Subjects for the investigation were 414 participants in the Fitness and Arthritis in Seniors Trial (FAST), and 362 patients with cardiovascular disease. Results from the FAST subjects showed that the ACSM equation was inappropriate for estimating VO2 during non-steady-state incremental treadmill walking. We developed the following equation (FAST) using speed and the interaction between speed and grade as the predictor variables during treadmill walking: VO2(ml.kg-1.min-1) = 0.0698 x speed(m.min-1) + 0.8147 x grade(%) x speed(m.min-1) + 7.533 ml.kg-1.min-1 The generalizability of the FAST equation for estimating VO2peak was evaluated in the patients with cardiovascular disease. The measured VO2peak of these patients was 23.7 +/- 0.3 ml.kg-1.min-1, whereas the VO2peak values estimated from the FAST equation and the ACSM equation were 24.1 +/- 0.3 and 33.2 +/- 0.5 ml.kg-1.min-1, respectively. No significant differences were found between the measured VO2peak and that estimated from the FAST equation. The VO2peak estimated from the ACSM equation was significantly greater than the measured VO2peak. These results suggest it is more appropriate to use the FAST equation rather than the ACSM equation to estimate VO2 in older patients with either osteoarthritis of the knee or cardiovascular disease.

Age Factors↗
PubMed1995

Long-term (5-year) changes in HDL cholesterol in cardiac rehabilitation patients. Do sex differences exist?

BACKGROUND: It is unknown whether the benefits of a cardiac rehabilitation program on HDL cholesterol (HDL-C) are equally achieved in men and women. To study this, we compared changes in HDL-C and other lipids in a large group of men and women participating in a cardiac rehabilitation program for up to 5 years. METHODS AND RESULTS: We compared changes in HDL-C and other fasting lipids in 553 men and 166 women participating in a cardiac rehabilitation program at baseline and then annually for up to 5 years. Patients exercised 3 days a week at 70% to 85% of their maximum heart rate predetermined by a symptom-limited treadmill test. Aerobic capacity was estimated in metabolic equivalents (METs), and percent body fat was determined by skin-fold measurements. Baseline HDL-C, LDL cholesterol (LDL-C), and total cholesterol were significantly higher in women, whereas the ratio of total cholesterol to HDL-C was lower. Although both men and women showed an increase in HDL-C after 1 year (10% and 7%, respectively), only the women's level continued to increase over 5 years (20% versus 5% for men, P = .03). The sex difference in change in HDL-C remained after adjustment for age and smoking. A nonsignificant trend toward a greater change in HDL-C in women existed after adjustment for baseline percent body fat and estimated METs. The change in the ratio of total cholesterol to HDL-C was also more favorable in women, with a 38% decrease over 5 years compared with a 14% decrease in men (P = .01). Total cholesterol decreased by 20% in women and 8% in men (P = .001), whereas LDL-C dropped by 34% in women and 15% in men (P = .0001). There was no sex difference in change in triglycerides. CONCLUSIONS: Women with heart disease who participate in a cardiac rehabilitation program may achieve greater lipid benefits over longer periods of time than previously demonstrated in men.

Aged↗
PubMed1994

Effects of captopril on ischemic events after myocardial infarction. Results of the Survival and Ventricular Enlargement trial. SAVE Investigators.

BACKGROUND: In the Survival and Ventricular Enlargement (SAVE) trial, recurrent myocardial infarction (MI) was the most important predictor of a poor outcome and conferred a sevenfold increase in risk of death. The purpose of this study was to determine the predictors of recurrent MI in study participants and to examine the influence of the angiotensin-converting enzyme inhibitor captopril on this and other myocardial ischemic events. METHODS AND RESULTS: The 2231 patients had survived the acute phase of MI (3 to 16 days) and had a radionuclide ventricular ejection fraction < or = 40%. Patients were randomly assigned to receive double-blind treatment with either placebo or captopril and were followed for an average of 42 months. The influence of captopril on recurrent MI, cardiac revascularization procedures, and hospitalization with unstable angina was examined. The likelihood of recurrent MI was greater in patients with an MI or functional disability before the index infarction and higher systolic pressure (all P < .001) but was not influenced by baseline left ventricular ejection fraction. Therapy with captopril reduced the risk of development of recurrent MI by 25% (95% confidence intervals, 5% to 40%; P = .015) and the risk of death after recurrent MI by 32% (95% confidence intervals, 4% to 51%; P = .029). Captopril-assigned patients were also less likely to require cardiac revascularization procedures (P = .010), but hospitalization for unstable angina was unaltered. When all three of these major coronary ischemic events were considered together, captopril therapy reduced the risk (14% risk reduction; 95% confidence intervals, 0% to 26%; P = .047). CONCLUSIONS: In post-MI patients with asymptomatic left ventricular dysfunction, long-term administration of captopril reduced recurrence of MI and the need for cardiac revascularization but had no influence on the rate of hospitalization with a discharge diagnosis of unstable angina. The finding that the recurrence of MI was independent of left ventricular ejection fraction suggests that captopril could be useful in preventing recurrent MI in patients with more preserved left ventricular function. The need for cardiac revascularization was reduced in patients receiving long-term captopril therapy, suggesting either an anti-ischemic effect or the ability of the angiotensin-converting enzyme inhibitor to modify the atherosclerotic process in survivors of MI.

Angina, Unstable↗
PubMed1993

Should patients with heart disease exercise in the morning or afternoon?

OBJECTIVE: To compare the cardiovascular risk of exercise in the morning and afternoon in patients with established heart disease. DESIGN: Retrospective cohort study. PATIENTS: Patients with established heart disease referred for participation in a comprehensive cardiac rehabilitation program. INTERVENTION: Supervised, submaximal exercise (1 hour three times per week) performed either in the morning (7:30 AM) or the afternoon (3 PM). MAIN OUTCOME: Documented cardiac events that occurred while patients were exercising in the rehabilitation programs. RESULTS: There were five cardiac events in 168,111 patient-hours of exercise in the morning, with an incidence of 3.0 +/- 1.3 events per 100,000 patient-hours. There were two events during the 84,491 patient-hours of exercise in the afternoon, for an incidence of 2.4 +/- 1.5 events per 100,000 patient-hours (not significant). The risk ratio of cardiac events during exercise in the morning compared with the afternoon was 1.27 (95% confidence interval, 0.25 to 6.55). CONCLUSION: In patients with coronary artery disease, the incidence of cardiac events is low during regular, submaximal exercise whether performed in the morning or the afternoon.

Adult↗
PubMed1992

Acute exercise: buffering psychosocial stress responses in women.

We evaluated the experimental hypothesis that an acute bout of aerobic exercise (AE) serves as a buffer to psychosocial stress responses in low to moderate physically fit women. Forty-eight (24 White, 24 Black) 25- to 40-year-old women participated in two counterbalanced experimental conditions: an attention control and a 40-min bout of AE at 70% heart rate (HR) reserve. The attention control and AE treatments were followed by (a) 30 min of quiet rest, (b) exposure to mental and interpersonal threat, and (c) 5 min of recovery. Blood pressure (BP) and HR were monitored at baseline, during the stressors, and throughout recovery. Self-reported distress was assessed before each stressor and upon completion of the recovery period. The results provided clear evidence that exercise dampens BP reactivity to psychosocial stress. Additionally, compared with the attention placebo control, AE reduced both the frequency and intensity of anxiety-related thoughts that occur in anticipation of interpersonal threat and challenge.

Adaptation, Psychological↗
PubMed1992

Rapid inactivation of infectious pathogens by chlorhexidine-coated gloves.

OBJECTIVE: Gloves containing chlorhexidine gluconate in an instant-release matrix on their inner surface (CHG gloves) were tested to determine their ability to rapidly inactivate infectious pathogens that may permeate or leak through the latex surface. DESIGN: CHG gloves were exposed for 1 to 10 minutes to blood or media containing infectious pathogens (e.g., bacteria, fungi, parasites, and viruses) as well as to lymphocytes and macrophages that are known to be the primary carriers of human immunodeficiency virus (HIV). Inactivation of pathogens was determined either by in vitro assay or in vivo infectivity. Stressed control and CHG glove fingers were submerged in a viral pool (retrovirus or bacteriophage) and after a set time, the glove interiors were checked for presence of permeated virions. RESULTS: CHG gloves rapidly inactivate all the pathogens tested including retrovirus and hepatitis B virus (90% to 100%). In the stressed glove fingers, live virus was detected in 26% of the control group but not in any of the CHG group. CONCLUSIONS: The use of CHG gloves may reduce the risk of exposure to infectious fluid-borne pathogens should the integrity of the latex barrier be compromised by overt failure or by permeation of viruses. Rapid destruction of lymphocytes and macrophages may facilitate inactivation of HIV associated with these cells. Tests have shown that CHG coating does not alter physical properties of the glove, and, furthermore, CHG gloves do not show potential for dermal irritation or sensitization.

Animals↗