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Biomedical subjects

R L Vogel

Publications and source records attributed to R L Vogel.

At least 37 records · Page 2Linked to original sources
PubMed1996

Primary ablation of atrial flutter and atrial fibrillation.

Direct treatment of atrial flutter and atrial fibrillation--that is, attempting to prevent arrhythmia recurrences by ablating atrial tissue--has been a challenge because of uncertainty about the location of optimal target tissues as well as the amount of atrial tissue requiring destruction to effect cure. Advances have yielded success rates for ablation of the common form of atrial flutter comparable to those for other types of supraventricular tachycardia and provide reason for optimism about the use of catheter techniques, to treat atrial fibrillation definitively. This article discusses some of these advances as well as the current status of catheter ablation for atrial flutter and atrial fibrillation and, finally, what the future may bring.

Animals↗
PubMed1996

P2 flash visual evoked response delay may be a marker of cognitive dysfunction in healthy elderly volunteers.

In an earlier study, 31 healthy elderly volunteers had normal cognitive function as measured by the Mini-Mental State Examination. Twenty-seven returned for further memory testing using the Wechsler Memory Scale-Revised (WMS-R). The P2 latency of the flash visual evoked response was positively correlated with age (p = .0008), but was not significantly related to gender. Nine of these 27 putatively healthy subjects had a delayed P2, suggestive of dementia. Although unaware of any memory deficits, 5 of the 27 had WMS-R Visual Memory Span percentile scores 1 or more standard deviations less than age-matched controls. Four of the five also had a significantly delayed P2 component. This positive correlation, adjusted for age, between poor Visual Memory Span performance and a delayed P2 was statistically significant (p < .025). These findings suggest that a delayed P2 in putatively healthy subjects is indicative of a visuospatial deficit which might be a precursor of dementia later.

Aged↗
PubMed1996

What providers need to know bout the False Claims Act.

In the 1990s, the Federal government's antifraud efforts increasingly have focused on the healthcare industry, and the False Claims Act, a powerful law designed to curb fraud against the Federal Treasury, has been one of the government's most potent weapons. One reason for the act's potency is its qui tam provision, which encourages whistleblowers to expose fraud in return for a substantial percentage of money the government recovers. The False Claims Act has been used against healthcare providers in the following areas: billing for services or supplies not actually provided, billing for nonreimbursable services, using false diagnoses to justify claims, and cheating in government performance evaluations.

Duty to Warn↗
PubMed1995

Oral terbutaline in the outpatient management of preterm labor.

OBJECTIVE: Our purpose was to prove our hypothesis that once preterm uterine contractions and/or labor is controlled with intravenous tocolysis, oral terbutaline, as a maintenance drug, does not prolong pregnancy. STUDY DESIGN: Before discharge, 184 patients between 24 and 35 completed weeks' gestation were prospectively randomized to continued bed rest either with or without oral terbutaline. Assignment was made with stratification into four groups: group 1, those patients with a Bishop score > or = 5 with oral terbutaline (n = 50); group 2, those with a Bishop score > or = 5 without oral terbutaline (n = 53); group 3, those with a Bishop score < 5 with oral terbutaline (n = 41); group 4, those with a Bishop score < 5 without oral terbutaline (n = 40). Oral terbutaline was discontinued at 37 completed weeks. RESULTS: No statistically significant differences were found in the number of readmissions, the number of unscheduled hospital visits, and the neonatal outcomes among the four groups. The gestational age at delivery and percent of deliveries at > or = 37 weeks were not significantly different when group 1 was compared with group 2 and group 3 was compared with group 4. CONCLUSION: Oral terbutaline maintenance does not improve pregnancy outcome in patients who have had initial successful intravenous tocolysis.

Administration, Oral↗
PubMed1995

Surgery in nonagenarians: morbidity, mortality, and functional outcome.

BACKGROUND: There are few studies that document the outcomes experienced by very old patients who undergo major surgery. METHODS: This is a case series and 7-year follow-up of 116 consecutive patients who were aged 90 years or older and underwent major surgery at a large university-affiliated community hospital. We describe the functional status, short- and long-term mortality, and predictors of mortality in this group of frail elders. RESULTS: The 116 nonagenarians in this study underwent 134 major operations. Sixty-three patients were admitted to the hospital from a nursing home. The most common surgical procedures were for hip fracture, lower extremity amputation, and abdominal problems. Nineteen patients died in the hospital following surgery, and 23 patients died within 30 days of operation. Follow-up at 7 years revealed that all but three patients had died. Survival was worse for patients admitted from nursing homes, those who were nonambulatory before surgery, and those with major or complete functional impairment. CONCLUSIONS: Major surgery in nonagenarians is associated with a 20% perioperative mortality. Functional status and ambulatory ability are maintained in most patients. Whether to operate on these frail elders is a complex decision.

Aged↗
PubMed1994

Parametric survival analysis of adjuvant therapy for stage II breast cancer.

BACKGROUND: Standard, nonparametric statistical methods estimate only the impact of therapy on survival rate up to a selected follow-up interval. In contrast, parametric methods can estimate the impact of treatment on the two cardinal parameters of malignancy: likelihood of cure and recurrence free survival time among uncured patients. METHODS: The authors screened a total of six parametric survival models. Three of these, including the log normal model, were applied to survival data from five clinical trials of adjuvant therapy for Stage II breast cancer. For comparison, the log rank test, a standard nonparametric method, was also applied to the same data. RESULTS: Both parametric and nonparametric methods identified a significant therapeutic in three of the five trials. In only one of these three trials, however, did parametric analysis identify a significant difference in the likelihood of cure between treatment groups. In the remaining two trials, a significant difference was found in recurrence free survival time among uncured patients. The three parametric survival models gave similar results. CONCLUSION: These findings suggest that parametric analysis may warrant further study as a method for measuring the long term clinical impact of adjuvant therapy on Stage II breast cancer.

Breast Neoplasms↗
PubMed1994

Helicobacter pylori is associated with alterations in intestinal gas profile among patients with nonulcer dyspepsia.

The pathogenesis of nonulcer dyspepsia (NUD) is unknown. Gas and postprandial bloating are frequent symptoms. The role of Helicobacter pylori (HP) in the pathogenesis of NUD is controversial. We studied the intestinal gas profile of NUD patients (N = 34) at baseline and after lactulose administration. The prevalence of hydrogen and methane producers was similar among HP+ and HP- patients. Breath H2 concentrations in response to lactulose showed significantly greater rise among HP+ subjects (P < 0.0001). HP positivity was associated with higher total breath excretion for H2 and methane combined (2984 +/- 1038 vs 1776 +/- 521 ppm/hr) compared to HP- subjects (P < 0.05). There was no correlation between peak H2 and methane levels. The role of alterations in intestinal gas in producing symptoms in HP+ patients with NUD needs further investigation.

Adult↗
PubMed1994

Dobutamine two-dimensional transesophageal echocardiographic stress testing for detection of coronary artery disease.

Atrial pacing and dipyridamole transesophageal echocardiography have been shown to be sensitive and specific tests for the detection of coronary artery disease. However, the sensitivity and specificity of dobutamine transesophageal echocardiography have not been reported. The purpose of this study was to determine the feasibility, sensitivity, and specificity of dobutamine transesophageal echocardiography for the detection of coronary artery disease. Transesophageal echocardiographic assessment of left ventricular function was performed in 81 adult patients aged 62 +/- 12 years during stepwise infusion of dobutamine from 5.0 to 40 micrograms/kg/min. Ischemia was diagnosed by the development of severe hypokinesis, akinesis, or dyskinesis of a previously contractile left ventricular segment. Coronary artery disease was defined by angiography as a reduction in luminal diameter of > or = 70% of an epicardial or > or = 50% of the left main coronary artery. In patients who had undergone coronary artery bypass graft surgery, a stenotic bypass graft was defined as a reduction in luminal diameter of > or = 70%. In patients without previous CABG, significant coronary artery disease was present in 21 patients: 5 with single-vessel disease, 7 double-vessel disease, 8 triple-vessel disease, and 1 left main coronary disease. Dobutamine transesophageal echocardiography had a sensitivity of 90% (19 of 21) and specificity of 94% (49 of 52) for the detection of coronary artery disease. In patients with previous CABG (n = 8), the sensitivity and specificity for the detection of bypass graft stenosis were 100% (4 of 4) and 75% (3 of 4), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Lack of delay in hepatic insulin transit as indicated by concordance of insulin secretory and peripheral insulin pulses.

The liver is an important site of insulin metabolism and action. It has often been assumed that the liver may diminish the amplitude of the insulin secretory waveform without altering hepatic insulin transit time. However, the significant extraction and metabolism of hepatic insulin has the potential to delay hepatic insulin transit. To examine hepatic insulin transit, we studied the concordance of calculated insulin secretory peaks with peripheral insulin peaks in 12 healthy men of varying body weight and fat distribution. Adiposity was determined by percent body fat, and fat distribution by the waist to hip ratio. Arterialized peripheral venous samples for insulin and C-peptide assays were obtained every 2 minutes for 90 minutes. Pancreatic insulin secretion rates were estimated with individual C-peptide kinetics using a two-compartment model. Concordance between insulin secretory peaks and peripheral insulin peaks was assessed by the hypergeometric probability model. A significant concordance between secretory and peripheral insulin pulses was demonstrated in seven of 12 subjects (P < .00001). The mean pulse intervals for insulin secretion were similar to the mean pulse intervals for peripheral insulin. The degree of concordance between the insulin secretory peaks and peripheral insulin pulses was unrelated to adiposity or body fat distribution. Significant synchronicity exists between insulin secretory peaks and peripheral insulin peaks in healthy men. We conclude that despite significant hepatic insulin extraction and metabolism, hepatic insulin transit may not be delayed in healthy men.

Adult↗
PubMed1994

Intra-articular morphine after arthroscopic knee operation.

Reports on pain relief with intra-articular morphine after arthroscopic knee operation are conflicting. To assess the long-term antinociceptive effect of intraarticular morphine, we studied pain at rest, pain on standing and ability to walk for 7 days after intraarticular injection of bupivacaine 100 mg (group 1, n = 11), bupivacaine 100 mg and morphine 1 mg (group 2, n = 10) and bupivacaine 100 mg and morphine 3 mg (group 3, n = 10) at the end of operation. Pain and walking were assessed by visual analogue and walking scales, respectively. Pain was treated with morphine i.v. in the recovery room and Tylenol No. 3 after discharge. Assessments were made before operation, and 1, 3, 6 and 12 h after injection and on days 1-7 after operation. There were significant differences between the groups in pain scores (pain at rest, P < 0.05; pain on standing, P < 0.01). The pain scores in group 3 were lower than those in group 1. The differences in pain scores at rest were significant at 12 h and on day 1 after operation and differences in pain scores on standing were significant at 12 h and on days 1 and 2 after operation. The scores in group 2 were intermediate between those in groups 1 and 3. The walking scores in group 3 were significantly better than those in group 1 at 12 h. The amount of analgesics received in groups 2 and 3 was significantly less than that in group 1 until day 3 after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthroscopy↗
PubMed1994

The effect of intravenous ranitidine and metoclopramide on behavior, cognitive function, and affect.

Both ranitidine and metoclopramide produce neuropsychiatric side effects. Concomitant use of these drugs preoperatively may produce adverse behavioral and emotional changes. Therefore, in 123 unpremedicated patients undergoing tubal occlusion, behavior, cognitive function, and affect were studied before and after a 2-min intravenous injection of placebo (n = 30), ranitidine 50 mg (n = 32), metoclopramide 10 mg (n = 30), or both ranitidine 50 mg and metoclopramide 10 mg (n = 31). Cognitive function was evaluated by the responses to 11 statements devised to assess attitude toward anesthesia and surgery. Affect was assessed by the word chosen out of 11 word-pairs as best describing the feelings at the time. After ranitidine injection, one patient seemed restless and five seemed drowsy. The changes were associated with subjective feelings of agitation (P < 0.05) and restlessness (P < 0.05). After metoclopramide injection, 6 (20%) developed akathisia, 13 (43.3%) seemed restless, and 8 (26.7%) seemed drowsy. The changes were associated with subjective sensation of jumpiness (P < 0.01) and discomfort (P < 0.05). When both ranitidine and metoclopramide were injected, 10 (32.3%) developed akathisia, 4 (12.4%) seemed restless, and 11 (35.5%) seemed drowsy. The changes were associated with subjective feelings of agitation (P < 0.05), jumpiness (P < 0.05), restlessness (P < 0.01), and upset (P < 0.05). Akathisia, a side effect of metoclopramide, seemed to be more prominent when ranitidine was added.

Adult↗
PubMed1994

Effect of caffeine and/or cigarette smoking on resting energy expenditure.

The thermic effect of cigarette smoking is dampened by the thermic effect of a meal, but potentiated by the thermic effect of exercise. The impact of the combined influences of caffeine and cigarette smoking is unknown. We examined the 3-h thermic response to smoking four 0.8 mg nicotine cigarettes, ingesting 200 mg of caffeine, or both, in ten fasted healthy men. Smoking four 0.8 mg nicotine cigarettes increased resting energy expenditure (REE) by 3.3% over a 3 h measurement period. Consumption of 200 mg of caffeine in the fasted condition increased REE of the smokers by 4.8% over 3 hours. Smoking four 0.8 mg cigarettes and ingesting 200 mg of caffeine significantly increased REE by 7.5% during the 3 h measurement period. At times early in the observation period, the combined thermic effect of cigarettes and caffeine was more than additive, but the effect was short-lived. A control group of nonsmokers was studied comparing REE following placebo or 200 mg of caffeine. Caffeine increased REE in the non-smoking controls 6.7%. This was not significantly different from results obtained on smokers. Fasted and non-smoking (baseline) REE was similar in smokers and non-smoking control subjects. It was concluded that the effects of caffeine on REE are additive.

Adolescent↗
PubMed1993

Pulsed Doppler transesophageal echocardiographic determination of cardiac output in human beings: comparison with thermodilution technique.

Measurement of cardiac output is a clinically valuable and widely used index of cardiac function. Although transesophageal echocardiography has been used to assess left ventricular function, little data exist on the accuracy of this technique in the measurement of cardiac output. Therefore cardiac output derived by pulsed Doppler transesophageal echocardiography and thermodilution methods were compared in adult patients being mechanically ventilated. The left ventricular outflow tract diameter was determined from a transgastric long-axis view of the left ventricle by using the transverse plane and longitudinal plane of the transesophageal scope. The cross-sectional area of the left ventricular outflow tract was calculated from the diameter assuming a circular shape. Pulsed Doppler recordings were obtained at the left ventricular outflow tract. Doppler time-velocity integrals were measured from the leading edge of the velocity curve. Cardiac output derived by transesophageal echocardiography was calculated as time-velocity integral multiplied by left ventricular outflow tract area and heart rate. Cardiac output derived by transesophageal echocardiography from the transverse plane (n = 26) and longitudinal plane (n = 22) were correlated with simultaneous thermodilution measurements. Thermodilution-derived cardiac output demonstrated excellent correlation with cardiac output measured by using transesophageal echocardiography from the transverse plane (r = 0.97, SEE = 0.84 L/min; p < 0.0001) and longitudinal plane (r = 0.95, SEE = 0.97 L/min; p < 0.0001). Transesophageal echocardiography is a promising technique in the measurement of cardiac output and expands the clinical use of this modality in the assessment of cardiac function.

Adult↗
PubMed1993

Lack of insulin feedback inhibition in non-obese and obese men.

The existence of insulin feedback inhibition is a controversial issue. The present study adopted a novel approach to determine whether insulin feedback inhibition exists in vivo during physiologic hyperinsulinemia and if it could contribute to enhanced insulin secretion in obesity. Serial plasma insulin and C-peptide levels were determined during a basal state and a hyperinsulinemic clamp (287 pmol/min/m2) and following discontinuation of the insulin infusion under euglycemic conditions. Insulin secretion rates were derived from plasma C-peptide levels and individual C-peptide kinetics using a two-compartment model. Eight non-obese and nine obese men were recruited for the studies, which were performed in random order. Men with significant variations in glucose levels during hyperinsulinemia were excluded from the analysis. Plasma glucose levels were similar between the non-obese and obese groups during all phases of the study, and similar plasma insulin levels were achieved in both groups during euglycemic hyperinsulinemia. In obese men, C-peptide levels were significantly greater compared with non-obese men during euglycemic hyperinsulinemia (P < .05). However, neither the non-obese nor the obese group demonstrated significant suppression of insulin secretion rates during euglycemic hyperinsulinemia. Expressing the data in absolute terms or as a percent of basal did not alter the results. Moreover, there was no significant change between the non-obese and the obese group during the rapid onset and cessation of hyperinsulinemia. Under euglycemic conditions, physiologic hyperinsulinemia does not induce suppression of endogenous insulin secretion in non-obese or obese men.

Adult↗
PubMed1993

Assessing the impact of adjuvant therapy on cure rate for stage 2 breast carcinoma.

The log-rank test is commonly used to assess therapeutic effect in prospective, randomised clinical trials. This test is sensitive to differences in survival between treatment groups at a specific endpoint, but cannot determine whether such a difference is due to an enhanced cure rate or an enhanced survival time among uncured patients. To investigate the clinical impact of such limitations, an algorithm was constructed to simulate clinical, randomised, adjuvant therapy trials in patients with a cured fraction of 0.27 and a median survival time for uncured patients of 3.4 years. Hypothetical therapies were introduced to increase rate of cure, increase median survival time, or achieve a combination of these effects. For 500 simulated patients recruited over a 5 year period and then followed for three additional years, a 50% enhancement of median survival time (to 5.1 years) led to a survival increase detectable at the P = 0.05 level in 780 of 1000 trials, whereas a 50% enhancement of cured fraction (to 40.5%) led to a detectable increase at the same level in only 449 of 1000 trials. These findings suggest that, in clinical trials of adjuvant therapy for stage 2 breast cancer, the log rank test may be more sensitive to increases in tumour-related survival time than to increases in cured fraction.

Algorithms↗
PubMed1993

A model of long-term survival following adjuvant therapy for stage 2 breast cancer.

Following adjuvant therapy for breast cancer, some patients will die of this tumour while the remainder will die of other causes. Deaths from breast cancer tend to follow a lognormal distribution, while deaths from other causes can be approximated by national demographic data. By combining these two survival models, we have generated an age-specific method for estimating the impact of treatment on overall long-term survival. Treatment was designed to operate by one of two mechanisms: an increase in cured fraction, or an increase in median tumour-related survival time among uncured patients. This analysis revealed that, for young and middle-aged patients, an increase in cured fraction has substantially greater long-term clinical impact than an increase in median survival time. Unfortunately, the non-parametric tests traditionally used in prospective clinical trials cannot distinguish between these two mechanisms of action.

Age Factors↗