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)
Interpretation of the electronic fetal heart rate during labor.
Electronic fetal heart rate monitoring is commonly used to assess fetal well-being during labor. Although detection of fetal compromise is one benefit of fetal monitoring, there are also risks, including false-positive tests that may result in unnecessary surgical intervention. Since variable and inconsistent interpretation of fetal heart rate tracings may affect management, a systematic approach to interpreting the patterns is important. The fetal heart rate undergoes constant and minute adjustments in response to the fetal environment and stimuli. Fetal heart rate patterns are classified as reassuring, nonreassuring or ominous. Nonreassuring patterns such as fetal tachycardia, bradycardia and late decelerations with good short-term variability require intervention to rule out fetal acidosis. Ominous patterns require emergency intrauterine fetal resuscitation and immediate delivery. Differentiating between a reassuring and nonreassuring fetal heart rate pattern is the essence of accurate interpretation, which is essential to guide appropriate triage decisions. (+info)
Can subretinal microphotodiodes successfully replace degenerated photoreceptors?
The idea of implanting microphotodiode arrays as visual prostheses has aroused controversy on its feasibility from the moment it appeared in print. We now present results which basically support the concept of replacing damaged photoreceptors with subretinally implanted stimulation devices. Network activity in degenerated rat retinae could be modulated through local electrical stimulation in vitro. We also investigated the long term stability and biocompatibility of the subretinal implants and their impact on retinal physiology in rats. Ganzfeld electroretinograms and histology showed no significant side effect of subretinal implants on retinal function or the architecture of the inner retina. (+info)
Platelet count, platelet size, and circulating platelet biomass concentration estimates made with an erythrocyte-calibrated electronic sizing system on EDTA-anticoagulated blood samples gave population medians and 95% ranges for 145 asymptomatic Mediterranean and 200 healthy Northern European subjects. The Mediterraneans had lower platelet counts [161,000 (89,000-290,000)/mul compared with 219,000 (148,000-323,000)/mul] and higher arithmetic mean volumes [17.8 (10.8-29.2) cu mum compared with 12.4 (9.9-15.6) cu mum], while the individual lognormal platelet size distribution profiles were comparable [geomatric standard deviations of 1.78 (1.60-1.98) against 1.70 (1.54-1.88)]; and the platelet biomass concentrations, given by count per microliter times mean volume times 10- minus 7 and expressed as a volumetric percentage of whole blood, were almost identical [0.286% (0.216%-0.379%) against 0.272% (0.201%-0.367%)]. Mediterranean macrothrombocytopenia is, therefore, considered a benign morphologic variant that requires differentiation from thrombocytopenias in which the circulating platelet biomass concentration is decreased. (+info)
Platelet size in man.
The shape and parameters of platelet size distributions were studied in 50 normal persons and 97 patients in order to test the proposed thesis that platelet size heterogeneity results mainly from aging in the circulation. This thesis was contradicted (1) by size distributions of age-homogeneous, newly-born cell populations which were lognormal with increased (instead of decreased) dispersion of volumes and (2) by the macrothrombocytosis found in some populations with normal age distribution. For these reasons, thrombocytopoiesis appeared to play the major role in determining platelet size. A model was built in which the volume variation of platelet territories due to megakaryocyte growth and membrane demarcation at each step of maturation was a random proportion of the previous value of the volume. This model explains the lognormal shape of both newborn and circulating platelet size distributions. It also implies that (1) the mean and standard deviation of platelet logvolumes depend on the rates of volume change of the individual platelet territories (growth rate minus demarcation rate) as well as on megakaryocyte maturation time; (2) platelet hyperdestruction causes an increase in the mean and dispersion of the rates of territory volume change; (3) Mediterranean macrothrombocytosis and some hereditary macrothrombocytotic thrombocytopenias or dysthrombocytopoieses reflect a diminished rate of territory demarcation, and (4) platelet size heterogeneity is caused mainly by the variations in territory growth and demarcation and not by aging in the circulation. (+info)
Compliance with an oral asthma medication: a pilot study using an electronic monitoring device.
Compliance with prescribed asthma medication is commonly estimated from tablet counts for oral medications and canister weights for inhaled medications. Recently, electronic medication monitoring devices, developed to evaluate numerical compliance as well as drug use patterns, were used to assess compliance with inhaled steroids and beta2-agonists. This was the first study to electronically assess compliance with an oral asthma medication. Fifty-seven asthmatic patients, stable on inhaled beta2-agonists only with a mean FEV1 of 77% predicted (+/- 13%, SD) began 12 weeks of treatment with zafirlukast 20 mg twice daily. The monitoring device, an electronic TrackCap, recorded the date and time on each occasion that patients removed and replaced their medication bottle caps. Patients were told that compliance would be assessed as part of the study, but patients were not told about the specifics of the TrackCap. Compliance was defined: 1. as the number of TrackCap events per number of prescribed tablets; and 2. as the difference between number of tablets dispensed and number returned per number prescribed. Adherence was defined as the number of days with two TrackCap events at least 8 h apart per the total number of days' dosing. Forty-seven patients completed the study with a median compliance of 89% (mean. 80%) and a median adherence of 71% (mean, 64%) as measured by TrackCap events. Compliance as estimated from return-tablet count was slightly higher (median, 92%). High rates of compliance were maintained throughout the trial. These results show that compliance with and adherence to a treatment of an oral, twice-daily, maintenance asthma medication, such as zafirlukast, is high. (+info)
Experience with fetal monitoring in a university teaching hospital.
Fetal monitoring during labour may be expected to decrease perinatal losses and the number of infants born with brain damage. In a prospective study of intrapartum fetal monitoring in selected high-risk pregnancies in a Winnipeg hospital the monitoring rate was 26.5% and the cesarean section rate in the monitored group was 22.0%. The fetal outcome in the monitored group was better than in the unmonitored group. The establishment of a fetal intensive care unit is believed to be strongly desirable in improving fetal surveillance during labour. Fetal monitors should be stationed in the delivery room as well as in the first-stage room. (+info)
Erythrocyte volume distribution in normal and abnormal subjects.
Size-frequency distribution curves of erythrocytes were generated with the Coulter Counter in 73 normal subjects and patients. Mean corpuscular volume (MCV) determined by routine calculation and MCV determined by size-frequency distribution were similar in all normal subjects and in patients with a single population of erythrocytes. Some patients with iron-deficiency anemia, folate deficiency, and vitamin B12 deficiency had two discrete erythrocyte populations. Some patients with microcytic anemia were shown to have a population of normocytes in addition to the predominant microcytic population. Reticulocytes and normocytes were identified in two patients recovering from macrocytic anemia. Transfused blood was identified as a separate population in a patient with microcytic anemia. In cases with two erythrocyte populations, the MCV of the principal population, as determined from size-distribution curves, differed from the MCV of the entire erythrocyte pool, as was determined by routine methods. Analysis of sequential erythrocyte size distributions in patients under treatment demonstrated the dynamics of erythrocyte subpopulations. Anisocytosis was quantified and shown to be associated frequently with hospitalized patients. (+info)