Biomedical subjects

G L Pearce

Publications and source records attributed to G L Pearce.

45 records · Page 3Linked to original sources

PubMed1993

Effects of mitral stenosis on pulmonary venous flow as measured by Doppler transesophageal echocardiography.

Pulmonary venous flow as assessed by transesophageal echocardiography (TEE) is influenced by changes in left atrial pressure and function. In mitral stenosis (MS), normal left atrial hemodynamics are altered because there is a prolonged decay in diastolic pressure from the left atrium to the left ventricle and atrial function may be altered because of atrial fibrillation. To assess the effect of the prolonged atrial diastolic pressure decay caused by MS on pulmonary venous flow, we studied 27 patients with MS (mitral valve range 0.7 to 2.4 cm2) by pulsed-wave Doppler TEE of the left or right upper pulmonary vein, and compared results with those of 13 normal subjects. Of the 27 subjects with MS, 61% showed a blunted systolic flow pattern and 39% showed a normal flow pattern with greater systolic to diastolic flow ratio. Patients with atrial fibrillation had a predominantly blunted pattern, whereas patients with normal sinus rhythm exhibited both blunted and normal flow patterns. Patients with MS had a lower pulmonary venous peak systolic flow velocity and a longer diastolic pressure halftime than control subjects. Pulmonary venous peak systolic flow velocity was significantly decreased in the presence of atrial fibrillation (p = 0.004). The mitral valve pressure halftime significantly correlated with pulmonary venous diastolic pressure halftime (r = 0.54; p = 0.004) mitral valve area (r = -0.46; p = 0.02). In conclusion, it was found that MS alters pulmonary venous flow patterns, showing a decreased pulmonary venous systolic flow and a prolonged diastolic flow, which may be useful in assessing the hemodynamics of MS.

Adult↗

PubMed1993

Differentiation of constrictive pericarditis from restrictive cardiomyopathy by Doppler transesophageal echocardiographic measurements of respiratory variations in pulmonary venous flow.

OBJECTIVES: The purpose of this study was to test the utility of measuring respiratory variation in pulmonary venous flow by transesophageal echocardiography. BACKGROUND: Respiratory variation of atrioventricular and central venous flow velocities by Doppler echocardiography has been used to differentiate constrictive pericarditis from restrictive cardiomyopathy. METHODS: We performed pulsed wave Doppler transesophageal echocardiography of the left or right pulmonary veins in 31 patients with diastolic dysfunction. Fourteen patients had constrictive pericarditis, and 17 had restrictive cardiomyopathy. We measured the pulmonary venous peak systolic and diastolic flow velocities and the systolic/diastolic flow ratio with transesophageal echocardiography during expiration and inspiration. The percent change in Doppler flow velocity from expiration to inspiration (%E) was calculated. RESULTS: Pulmonary venous peak systolic flow in both inspiration and expiration was greater in constrictive pericarditis than in restrictive cardiomyopathy. The %E for peak systolic flow tended to be higher in constrictive pericarditis (19% vs. 10%, p = 0.09). In contrast, pulmonary venous peak diastolic flow during inspiration was lower in constrictive pericarditis than in restrictive cardiomyopathy. The %E for peak diastolic flow was larger in constrictive pericarditis (29% vs. 16%, p = 0.008). The pulmonary venous systolic/diastolic flow ratio was greater in constrictive pericarditis in both inspiration and expiration. The combination of pulmonary venous systolic/diastolic flow ratio > or = 0.65 in inspiration and a %E for peak diastolic flow > or = 40% correctly classified 86% of patients with constrictive pericarditis. CONCLUSIONS: The relatively larger pulmonary venous systolic/diastolic flow ratio and greater respiratory variation in pulmonary venous systolic, and especially diastolic, flow velocities by transesophageal echocardiography can be useful signs in distinguishing constrictive pericarditis from restrictive cardiomyopathy.

Blood Flow Velocity↗

PubMed1992

Comparison of Doppler and two-dimensional echocardiography for assessment of pericardial effusion.

Respiratory changes in left ventricular inflow velocities by Doppler echocardiography have been used to assess cardiac tamponade; however, Doppler echocardiography has not been compared to right atrial or right ventricular collapse. Pulsed Doppler echocardiography of left ventricular inflow velocities was performed with respiratory monitoring in 28 patients with small to large pericardial effusions. Ten of the 17 patients (59%) with large effusions had equalization of right-sided diastolic pressures before pericardial drainage. The measurements performed included percent change in left ventricular inflow peak early velocity, isovolumic relaxation time, change in inferior vena cava diameter from apnea to inspiration, and the presence of right atrial and right ventricular collapse. Percent change in early left ventricular inflow velocities significantly correlated with pericardial effusion size (p = 0.001) and right ventricular collapse (p = 0.007), and showed a trend with right atrial collapse (p = 0.10). Pericardial effusions with a left ventricular inflow velocity change > 22% were found to have right-sided equalization at a 95% confidence interval. Our data indicate that the respiratory changes in Doppler echocardiographic parameters are useful in the assessment of pericardial effusion and tamponade. This study concurs with the hypothesis that there is a continuum of hemodynamic compromise in pericardial effusion that is easily detected by Doppler echocardiography.

Adult↗

PubMed1991

Transesophageal Doppler echocardiography of pulmonary venous flow: a new marker of mitral regurgitation severity.

Pulmonary venous flow varies with different cardiac conditions. Flow patterns in response to mitral regurgitation have not been well studied, but flows may vary enough to differentiate among different grades of regurgitation. Accordingly, pulmonary venous flow velocities were recorded in 50 consecutive patients referred for outpatient (n = 26) or intraoperative (mitral valve repair; n = 24) echocardiographic examination for mitral regurgitation. Recordings were made of right and left upper pulmonary veins with pulsed wave Doppler transesophageal echocardiography. Mitral regurgitation was graded from 1+ to 4+ by an independent observer using transesophageal color flow mapping. The results of cardiac catheterization performed 5 weeks earlier in 43 of the patients were also graded for mitral regurgitation by an independent observer. Pulmonary venous flow patterns, the presence of reversed systolic flow and peak systolic and diastolic flow velocities were compared with the severity of mitral regurgitation indicated by each technique. Of the 28 patients with 4+ regurgitation by transesophageal color flow mapping, 26 (93%) had reversed systolic flow. The sensitivity of reversed systolic flow in detecting 4+ mitral regurgitation by transesophageal color flow mapping was 93% and the specificity was 100%. The sensitivity and specificity of reversed systolic flow in detecting 4+ mitral regurgitation by cardiac catheterization were 86% and 81%, respectively. Discordant flows were observed in 9 (24%) of 38 patients; the left vein usually showed blunted systolic flow and the right showed reversed systolic flow. In 22 intraoperative patients, there was "normalization" of pulmonary venous systolic flow after mitral valve repair in the postcardiopulmonary bypass study compared with the prebypass study after the mitral regurgitant leak was corrected.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗

PubMed1991

Prescription-event monitoring of 10,895 patients treated with alprazolam.

'Prescription-event monitoring' (PEM) is one of two national systems of post-marketing surveillance in operation in Britain. It identified 22,065 patients who had received NHS prescriptions for alprazolam, and data available on 10,895 of these were analysed. The main reasons for treatment with alprazolam were anxiety and depression. The patients provided 3360 patient-years of treatment and 7540 patient-years of follow-up. No serious events clearly associated with treatment were recorded. The main events reported during treatment, albeit infrequently, were drowsiness and depression, although depression is more likely to be due to the disorder being treated than to the drug. Some of the other alleged unwanted effects of alprazolam in published reports were not encountered. Since PEM is unable to determine the dependence potential of alprazolam, further evaluation of this problem is called for.

Adult↗

PubMed1990

Prescription-event monitoring: methodology and recent progress.

Event monitoring was first suggested 25 years ago as a way of detecting adverse reactions to drugs. Prescription-event monitoring (PEM), which has been developed by the Drug Safety Research Unit, is the first large-scale systematic post-marketing surveillance method to use event monitoring in the U.K. PEM identifies patients, who have been prescribed a particular drug, and their doctors from photocopies of National Health Service prescriptions which are processed centrally in England. A personalized follow-up questionnaire ("green form") is mailed to each patient's general practitioner, usually on the first anniversary of the initial prescription, asking for information about the patient, especially any "events" that he or she may have experienced since beginning treatment with the drug. The methodology of PEM is presented, together with examples of analyses that can be performed using results from recent studies. The problems and benefits of PEM are discussed.

Drug Prescriptions↗

PubMed1988

Postmarketing surveillance of enalapril. I: Results of prescription-event monitoring.

To identify and measure the incidence of adverse effects of the angiotensin converting enzyme inhibitor enalapril 13,713 patients were studied for one year by prescription-event monitoring. Precise information about the duration of treatment was available for 12,543 patients. The frequency of many events was calculated, including dizziness (483 patients; 3.9%), persistent dry cough (360; 2.9%), headache (310; 2.5%) hypotension (218; 1.7%), and syncope (155; 1.2%). Less common reactions included angioedema, urticaria, and muscle cramps. Altogether 1098 (8%) patients died and the notes of 913 of them (83%) were obtained for detailed scrutiny. With the exception of a few patients with renal failure who deteriorated during treatment (reported on separately), no death was attributed to enalapril. Enalapril was considered to be effective, even in patients with advanced cardiac failure. These results for enalapril are reassuring and provide further evidence of the value of prescription-event monitoring.

Adolescent↗

PubMedDate not supplied

Importance of sampling both pulmonary veins in grading mitral regurgitation by transesophageal echocardiography.

Pulmonary venous flow patterns have been used to assess severity of mitral regurgitation; however, the issue of which pulmonary veins to sample has not been determined. We performed pulsed wave Doppler transesophageal echocardiography of both the left and right upper pulmonary veins in 80 patients who had mitral regurgitation determined by independent transesophageal echocardiography color flow mapping. Pulmonary venous flow patterns, peak systolic and diastolic flow, and the presence of reversed systolic flow were compared between the left and right pulmonary veins for each grade of mitral regurgitation. Flow patterns were discordant in 20 (25%) of the 80 patients. Of the 43 patients with 4+ mitral regurgitation, there was discordant flow in 16 (37%) of the patients with mainly reversed systolic flow in the right upper vein, while there was blunted or normal systolic flow in the left upper vein. Of the 16 patients with discordant flows, 14 had eccentric jets, mainly anteromedial jets. We conclude that if discordant flow can occur in 25% of patients with mitral regurgitation and in 37% of patients with 4+ mitral regurgitation, then both pulmonary veins must be evaluated when assessing the severity of mitral regurgitation with pulsed wave Doppler transesophageal echocardiography.

Adult↗

PubMedDate not supplied

Front line workers in long-term care: the effect of educational interventions and stabilization of staffing ratios on turnover and absenteeism.

OBJECTIVE: Front line workers in long-term care play a crucial role in helping residents achieve their highest possible functional level. High turnover (rates in excess of 100% are common) and absenteeism threaten the ability of long-term care providers to meet this goal. The purpose of this study was to determine the effect of a formalized certified nursing assistant (CNA) education program and stabilization of staffing ratios on turnover and absenteeism. DESIGN AND SETTING: This study was a 12-month prospective, nonrandomized trial involving two long-term care facilities providing traditional intermediate and skilled care serving as study sites and a similar facility serving as a control. For historical comparisons, each facility served as its own control using data from the year before the interventions. INTERVENTIONS: An in-house educational program based on the State of North Carolina core curriculum for CNAs was instituted in each study site. During the study period, efforts were made to achieve stable staffing ratios of 1 CNA:8 residents for days, 1:10 for evenings, and 1:15 for nights. Traditional quality of care indicators and resident/surrogate satisfaction were tracked during the study period. RESULTS: Both study facilities showed a decline in turnover, with the decline reaching statistically significant levels at Facility B (134% to 41%, P = 0.0001). Absenteeism rates did not change significantly during the study period. Resident/surrogate satisfaction with nursing care was improved significantly at Facility B (P = 0.02). CONCLUSION: A formal education program in conjunction with stabilization of staffing ratios can result in lower turnover rates for CNA's and improved resident/surrogate satisfaction.

Journal Article↗