Pulmonary artery pressure variation in patients with connective tissue disease: 24 hour ambulatory pulmonary artery pressure monitoring.
BACKGROUND: The specific contribution of secondary pulmonary hypertension to the morbidity and mortality of patients with underlying lung disease can be difficult to assess from single measurements of pulmonary artery pressure. We have studied patients with secondary pulmonary hypertension using an ambulatory system for measuring continuous pulmonary artery pressure (PAP). We chose to study patients with connective tissue disease because they represent a group at high risk of pulmonary vascular disease, but with little disturbance of lung function. METHODS: Six patients (five with progressive systemic sclerosis and one with systemic lupus erythematosis) were studied. They underwent preliminary cardiopulmonary investigations followed by Doppler echocardiography, right heart catheterisation, and ambulatory pulmonary artery pressure monitoring to measure changes in pressure over a 24 hour period including during a formal exercise test. RESULTS: All patients had pulmonary hypertension as measured by Doppler echocardiography with estimated pulmonary artery systolic pressures of 40-100 mm Hg. Pulmonary function testing revealed virtually normal spirometric values (mean FEV1 86.9% predicted) but marked reduction in CO gas transfer factor (KCO 57.8% predicted). Exercise responses were impaired with mean VO2max 50.6% predicted. Ambulatory PAP monitoring indicated significant changes in pressures with variation in posture and activity throughout 24 hours. Resting PAP did not predict the change in PAP seen on exercise. CONCLUSION: Conventional methods of assessment of the pulmonary circulation based on single measurements in the supine position may underestimate the stresses faced by the right side of the circulation. This ambulatory system allows monitoring of pulmonary haemodynamics continuously over 24 hours during normal activities of daily living. These measurements may increase our understanding of the contribution made by secondary pulmonary hypertension to the morbidity and mortality of the underlying lung disease. (+info
Measurement of continuous ambulatory peritoneal dialysis prescription adherence using a novel approach.
OBJECTIVE: The purpose of the study was to test a novel approach to monitoring the adherence of continuous ambulatory peritoneal dialysis (CAPD) patients to their dialysis prescription. DESIGN: A descriptive observational study was done in which exchange behaviors were monitored over a 2-week period of time. SETTING: Patients were recruited from an outpatient dialysis center. PARTICIPANTS: A convenience sample of patients undergoing CAPD at Piedmont Dialysis Center in Winston-Salem, North Carolina was recruited for the study. Of 31 CAPD patients, 20 (64.5%) agreed to participate. MEASURES: Adherence of CAPD patients to their dialysis prescription was monitored using daily logs and an electronic monitoring device (the Medication Event Monitoring System, or MEMS; APREX, Menlo Park, California, U.S.A.). Patients recorded in their logs their exchange activities during the 2-week observation period. Concurrently, patients were instructed to deposit the pull tab from their dialysate bag into a MEMS bottle immediately after performing each exchange. The MEMS bottle was closed with a cap containing a computer chip that recorded the date and time each time the bottle was opened. RESULTS: One individual's MEMS device malfunctioned and thus the data presented in this report are based upon the remaining 19 patients. A significant discrepancy was found between log data and MEMS data, with MEMS data indicating a greater number and percentage of missed exchanges. MEMS data indicated that some patients concentrated their exchange activities during the day, with shortened dwell times between exchanges. Three indices were developed for this study: a measure of the average time spent in noncompliance, and indices of consistency in the timing of exchanges within and between days. Patients who were defined as consistent had lower scores on the noncompliance index compared to patients defined as inconsistent (p = 0.015). CONCLUSIONS: This study describes a methodology that may be useful in assessing adherence to the peritoneal dialysis regimen. Of particular significance is the ability to assess the timing of exchanges over the course of a day. Clinical implications are limited due to issues of data reliability and validity, the short-term nature of the study, the small sample, and the fact that clinical outcomes were not considered in this methodology study. Additional research is needed to further develop this data-collection approach. (+info
The vagaries of self-reports of physical activity: a problem revisited and addressed in a study of exercise promotion in the over 65s in general practice.
BACKGROUND: The assessment of levels of physical activity relies upon suitable measurement tools. OBJECTIVE: We aimed to investigate whether a practice nurse, using a motivational interview technique, could encourage older patients to increase their physical activity. METHODS: Health and well-being were monitored at baseline and 8 weeks following intervention. Physical activity levels were ascertained using both a self-report measure and ambulatory heart-rate monitoring. RESULTS: Whilst patients reported higher levels of physical activity at follow-up, this finding was not confirmed by the heart-rate data. CONCLUSION: The study concludes that patients tend to overestimate the amount of physical activity undertaken and that ambulatory heart-rate monitoring may be more useful for verifying actual behaviour. (+info
Anticoagulant properties, clinical efficacy and safety of efegatran, a direct thrombin inhibitor, in patients with unstable angina.
AIMS: Thrombin plays a key role in the clinical syndrome of unstable angina. We investigated the safety and efficacy of five dose levels of efegatran sulphate, a direct thrombin inhibitor, compared to heparin in patients with unstable angina. METHODS: Four hundred and thirty-two patients with unstable angina were enrolled. Five dose levels of efegatran were studied sequentially, ranging from 0.105 mg. kg(-1). h(-1)to 1.2 mg. kg(-1). h(-1)over 48 h. Safety was assessed clinically, with reference to bleeding and by measuring clinical laboratory parameters. Efficacy was assessed by the number of patients experiencing any episode of recurrent ischaemia as measured by computer-assisted continuous ECG ischaemia monitoring. Clinical end-points were: episodes of recurrent angina, myocardial infarction, coronary intervention (PTCA or CABG), and death. RESULTS: Efegatran demonstrated dose dependent ex-vivo anticoagulant activity with the highest dose level of 1.2 mg. kg(-1). h(-1)resulting in steady state mean activated partial thromboplastin time values of approximately three times baseline. Thrombin time was also increased. Neither of the efegatran doses studied were able to suppress myocardial ischaemia during continuous ECG ischaemia monitoring to a greater extent than that seen with heparin. There were no statistically significant differences in clinical outcome or major bleeding between the efegatran and heparin groups. Minor bleeding and thrombophlebitis occurred more frequently in the efegatran treated patients. CONCLUSION: Administration of efegatran sulphate at levels of at least 0.63 mg. kg(-1). h(-1)provided an anti-thrombotic effect which is at least comparable to an activated partial thromboplastin time adjusted heparin infusion. There was no excess of major bleeding. The level of thrombin inhibition by efegatran, as measured by activated partial thromboplastin time, appeared to be more stable than with heparin. Thus, like other thrombin inhibitors, efegatran sulphate is easier to administer than heparin. However, no clinical benefits of efegatran over heparin were apparent. (+info
Sleep/wake abnormalities in patients with periodic leg movements during sleep: factor analysis on data from 24-h ambulatory polygraphy.
Periodic Leg Movements (PLM) in sleep occur in a wide variety of sleep/wake disorders but their relationship with sleep disturbance, and notably with the concomitant existence of a 'restless legs' syndrome (RLS) remains unclear. We performed 24-h ambulatory polygraphy in a population of 54 consecutive, unselected patients with PLMs (Coleman's index greater than 5/h) who complained of different sleep disorders. A Principal Component Analysis (PCA) was conducted on seven variables from the sample, namely PLM index, patient's age, sleep stage changes per hour, sleep depth index (SWS+PS/TST), diurnal sleep time, number of awakenings exceeding 2 min and presence of a RLS. PCA yielded four independent factors. The PLM index and the changes of sleep stage clustered in a single factor, linking therefore sleep fragmentation to the frequency of PLMs. The second factor appeared to reflect a circadian sleep/wake disorder, combining diurnal sleep time with the number of long night awakenings. The third factor was mainly loaded by the patients' age and the sleep depth index, thus reflecting a well known relationship. Finally, the variable reflecting the existence of a RLS appeared isolated in a single factor, independent from the three previously described. These results confirm and extend the link between PLMs and sleep fragmentation, as well as the recently described dissociation between PLMs and diurnal somnolence. On the other hand, our analysis suggests that in PLM patients the concomitant existence of a RLS is not related to the frequency of occurrence of PLMs, at least when these latter are quantified independently of their arousal index. (+info
Spontaneous ambulatory activity as a quantifiable outcome measure for rheumatoid arthritis.
OBJECTIVE: To validate the objective monitoring of ambulatory activity as an outcome measure for rheumatoid arthritis (RA). METHODS: We have compared ambulatory activity to a range of currently favoured outcome measures, ranging from subjective opinions to X-ray damage, in a population of 93 RA sufferers. RESULTS: Correlations were stronger with measures of joint damage and disability, and less strong with measures of disease activity. Sensitivity to change was good. Three different interventions were compared for the quantity of the response, and the results agree with clinical experience, with steroid injection of the knee and use of non-steroidal anti-inflammatory drugs (NSAIDs) having a similar response and the provision of surgical shoes producing a more modest increase in ambulation. CONCLUSION: The measurement of ambulatory activity has validity for RA assessment. It provides different but related data to the currently used measures. It is objective, relevant, quantifiable and of unlimited scale. It could be used to quantify interventions aimed at increasing ambulation, in carefully constructed studies. (+info
Evaluation of guidelines for the use of telemetry in the non-intensive-care setting.
To determine if the American College of Cardiology (ACC) cardiac monitoring guidelines accurately stratify patients according to their risks for developing clinically significant arrhythmias in non-intensive-care settings, we conducted a prospective cohort study of 2,240 consecutive patients admitted to a non-intensive-care telemetry unit over 7 months. Sixty-one percent of patients were assigned to ACC class I (telemetry indicated in most patients), 38% to class II (telemetry indicated in some), and 1% to class III (telemetry not indicated). Arrhythmias were detected in 13.5% of the class I patients, 40.7% of the class II patients, and 12% of the class III patients (p <.001). Telemetry detected an arrhythmia resulting in transfer to an intensive care unit in 0.4% of the class I patients, 1.6% of the class II patients, and none of the class III patients (p =.006). Telemetry led to a change in management for 3.4% of the class I patients, 12.7% of the class II patients, and 4% of the class III patients (p <.001). When patients with chest pain as the reason for admission were moved from class I to class II and patients with arrhythmias as the reason for admission were moved from class II to class I, more arrhythmias and more clinically significant arrhythmias occurred in class I patients and the trends from class I to class III were more consistent with the purpose of the guidelines. These findings indicate that when the ACC guidelines are reexamined, consideration should be given to changing them so they are more useful in non-intensive-care settings. (+info
An ambulatory dyskinesia monitor.
OBJECTIVES: New treatments are now becoming available for the management of levodopa induced dyskinesias in Parkinsons's disease. However, assessment of their efficacy is limited by the inadequacies of current methods of dyskinesia measurement. The objective was to develop and validate a portable device capable of objectively measuring dyskinesias during normal daily activities. METHODS: A portable device was developed based on a triaxial accelerometer, worn on the shoulder, and a data recorder that can record levodopa induced dyskinesias. A computer program plots raw acceleration and acceleration over 0.5 Hz frequency bands against time. The acceleration in the different bands can then be compared with the raw acceleration trace, enabling identification and exclusion of confounding activities such as tremor and walking, which have a characteristic appearance on the trace. The validity of this device was assessed on 12 patients and eight age matched controls by comparing accelerations in the 1-3 Hz frequency band with established clinical dyskinesia rating scales. While wearing the monitor, subjects were videorecorded sitting and during dyskinesia provocation tasks, including mental activation tasks, eating, drinking, writing, putting on a coat, and walking. The dyskinesias were graded with both modified abnormal involuntary movement (AIM) and Goetz scales. The clinical ratings were then compared with the mean acceleration scores. RESULTS: Acceleration in the 1-3 Hz frequency band correlated well against both scales, during all individual tasks. Acceleration produced by normal voluntary activity (with the exception of walking, which produced large accelerations, even in controls) was small compared with dyskinetic activity. With walking excluded, the mean acceleration over the rest of the recording time correlated strongly with both the modified AIM (Spearman's rank (r=0.972, p<0.001) and Goetz (r=0.951, p<0.001) scales. CONCLUSIONS: This method provides an accurate, objective means for dyskinesia assessment, and compares favourably with established methods currently used. (+info