Biomedical subjects

J Winkelman

Publications and source records attributed to J Winkelman.

At least 19 recordsLinked to original sources

PubMed1999

A randomized trial of a computer-based intervention to reduce utilization of redundant laboratory tests.

PURPOSE: To determine the impact of giving physicians computerized reminders about apparently redundant clinical laboratory tests. SUBJECTS AND METHODS: We performed a prospective randomized controlled trial that included all inpatients at a large teaching hospital during a 15-week period. The intervention consisted of computerized reminders at the time a test was ordered that appeared to be redundant. Main outcome measures were the proportions of clinical laboratory orders that were canceled and the proportion of the tests that were actually performed. RESULTS: During the study period, there were 939 apparently redundant laboratory tests among the 77,609 study tests that were ordered among the intervention (n = 5,700 patients) and control (n = 5,886 patients) groups. In the intervention group, 69% (300 of 437) of tests were canceled in response to reminders. Of 137 overrides, 41% appeared to be justified based on chart review. In the control group, 51% of ordered redundant tests were performed, whereas in the intervention group only 27% of ordered redundant tests were performed (P <0.001). However, the estimated annual savings in laboratory charges was only $35,000. This occurred because only 44% of redundant tests performed had computer orders, because only half the computer orders were screened for redundancy, and because almost one-third of the reminders were overridden. CONCLUSIONS: Reminders about orders for apparently redundant laboratory tests were effective when delivered. However, the overall effect was limited because many tests were performed without corresponding computer orders, and many orders were not screened for redundancy.

Boston↗

PubMed1997

Does the computerized display of charges affect inpatient ancillary test utilization?

BACKGROUND: The computerized display of charges for ancillary tests in outpatients has been found to affect physician-ordering behavior, but this issue has not been studied in inpatients. OBJECTIVE: To assess whether the computerized display of charges for clinical laboratory or radiological tests affected physician-ordering behavior. PATIENTS AND METHODS: Two prospective controlled trials, randomized by patient, were performed. Each trial included all medical and surgical inpatients at 1 large teaching hospital during 4 and 7 months: 3536 intervention and 3554 control inpatients in the group with clinical laboratory tests, and 8728 intervention and 8653 control inpatients in the group with radiological tests. The intervention consisted of the computerized display of charges for tests at the time of ordering. MAIN OUTCOME MEASURES: The number of clinical laboratory and radiological tests ordered per admission and the charges for these tests. RESULTS: For the clinical laboratory tests, during a 4-month study period, patients in the intervention group had 4.5% fewer tests ordered, and the total charges for these tests were 4.2% lower, although neither difference was statistically significant. Compared with historical controls from the same 4-month period a year before, the charges for the tests per admission had decreased 13.3%, but the decrease was temporally correlated with a restriction of future ordering of tests, and not with the introduction of the display of charges. For the radiological tests, during a 7-month period, the intervention group had almost identical numbers of tests ordered and charges for these tests. CONCLUSIONS: The computerized display of charges had no statistically significant effect on the number of clinical laboratory tests or radiological procedures ordered or performed, although small trends were present for clinical laboratory tests. More intensive interventions may be needed to affect physician test utilization.

Computer Systems↗

PubMed1996

Screening for obstructive sleep apnea in patients presenting for snoring surgery.

Excessive mortality is associated with obstructive sleep apnea (OSA). Therefore it is important to diagnose OSA in patients presenting for snoring surgery. A prospective study was performed to develop screening models to detect OSA compared with universal polysomnography for sensitivity and cost. Multivariate analysis of 150 consecutive patients was based on clinical data, questionnaire data, and polysomnography. Two screening models obtained 100% sensitivity and reduced the need for polysomnograms. Cost savings of screening based on clinical data was projected to be $35 to $80 per patient using reported prevalence rates of OSA among snorers. A screening model for OSA using clinical data alone is more cost-effective than one that combines these data with pulse oximetry data, but savings over universal polysomnography were modest.

Adult↗

PubMed1996

Cord lactate, pH, and blood gases from healthy neonates.

Lactate, pH, pO2, and pCO2 were determined in arterial, venous, and free-flowing mixed umbilical cord blood obtained from deliveries of apparently healthy neonates. The goals of this study were to establish reference ranges for lactate and pH against which results in cases of high-risk labor and delivery could be compared, to see how the gases correlated with these values, and to determine whether easily accessible mixed umbilical cord blood can serve as the sample in lieu of cord arterial or cord venous blood. Arterial and venous cord lactates were 2.98 mmol/l (+/- 1.40) and 2.80 mmol/l (+/- 1.35), respectively, from 85 cords obtained from vaginal and cesarean deliveries. Mixed cord blood lactate, obtained on 48 cords, was 2.72 mmol/l (+/- 1.28) versus 3.14 and 2.97 mmol/l for the arterial and venous samples from those cords, respectively, and correlated quite well with lactate from the venous specimens (r = 0.97). Differences of > 0.5 mmol/l occurred between mixed and arterial cord bloods in 21 patients, and between mixed and venous cord bloods in 6 of the 48 patients, respectively. We conclude that (1) less than 2.5% of deliveries of apparently healthy neonates have arterial, venous, or mixed cord lactates > or = 7.0 mmol/l and pH < or = 7.15, (2) neither cord venous pO2 nor pCO2 correlate well with cord venous lactate, and (3) readily available mixed cord blood is a satisfactory specimen for the measurement of venous cord latate.

Carbon Dioxide↗

PubMed1994

Automated reticulocyte counting and measurement of reticulocyte cellular indices. Evaluation of the Miles H*3 blood analyzer.

This study evaluated reticulocyte counting and measurement of reticulocyte cellular indices with the Miles H*3 blood analyzer, a new instrument that combines the Technicon/Miles technology for blood cells counting with a staining technique allowing counting of reticulocytes, quantification of staining intensity and measurement of reticulocyte cellular indices. Reticulocyte counts obtained with the Miles H*3 analyzer were compared with those obtained by manual counting, flow cytometry (thiazole orange method) and by the Sysmex R-3000 (Baxter Diagnostics) reticulocyte analyzer. Reticulocyte counting with the Miles H*3 showed excellent precision, and linearity in the range tested (1.1-49% and 1-72% reticulocytes, respectively, with two different protocols) with no significant carryover. Reticulocyte counts were stable after storing blood samples for 72 hours at 4 degrees C. Comparison of the four different methods, showed an acceptable intraclass correlation between Miles H*3 and Sysmex R-3000 (intraclass correlation coefficient, [ri] = .952), Miles H*3 and flow cytometry (ri = .922), and Sysmex R-3000 and flow cytometry (ri = .938). There was no satisfactory correlation between any of the three automated methods and the values obtained with manual counting of reticulocytes (ri = .538-.755), consistent with the well known imprecision of the manual technique. For a group of normal pediatric subjects, age 1-10, we obtained the following values (+/- SD) of reticulocyte indices: mean corpuscular volume 97.6 +/- 4.7 fL; cell hemoglobin concentration mean 28.2 +/- 1.4 g/dL; cell hemoglobin content 26.7 +/- 1.6 pg. We determined the direct cost, including depreciation, of the manual and instrumental methods. Cost/test varied from $1.61 for manual method to $6.03 for the Sysmex R-3000. Cost/test for flow cytometry and Miles H*3 were $3.34 and $3.49, respectively.

Child↗

PubMed1991

Continuous arterial and venous blood gas monitoring during cardiopulmonary bypass.

A new monitoring technique, based on optical fluorescence chemistry, allows continuous monitoring of all blood gas variables during cardiopulmonary bypass. To evaluate the clinical performance of this monitor, we drew 220 arterial and 216 venous blood samples from 15 patients, and simultaneous blood gas values displayed by the monitor were compared with standard laboratory measurements. The continuous monitor predicted laboratory values with varying degrees of accuracy. (R2 values by linear regression: arterial oxygen tension 0.86, venous oxygen tension 0.36, arterial carbon dioxide tension 0.58, venous carbon dioxide tension 0.72, arterial pH 0.53, venous pH 0.58; pH 0.53, venous pH 0.58; p less than 0.0001). Monitor values of arterial oxygen tension overestimated laboratory values (bias = + 43.5 mm Hg), but the laboratory reference method likely underestimated true arterial oxygen tension in the high range achieved on bypass. Monitoring of venous oxygen tension was imprecise (precision = +/- 6.51 mmHg), regardless of whether stable conditions existed during the sampling period. Monitoring of carbon dioxide tension and pH showed small bias (carbon dioxide tension within 2 mm Hg, pH within 0.03) and good precision (carbon dioxide tension within 3 mm Hg, pH within 0.03). With the development of unstable conditions on bypass, monitor arterial oxygen tension values showed a changing relationship to corresponding laboratory values. In conclusion, arterial and venous carbon dioxide tension and pH monitoring provide acceptably accurate alternatives to laboratory measurement of these variables during cardiopulmonary bypass. Arterial oxygen tension monitoring accurately indicates changes in oxygen tension in the arterial oxygen tension range typically produced during extracorporeal circulation. Oxygen tension monitoring in the venous oxygen tension range is too imprecise for clinical decision-making purposes.

Aged↗

PubMed1989

Detection of specific IgG and IgA antibodies to Chlamydia trachomatis in women with salpingitis confirmed by laparoscopy.

The sera from 12 consecutive symptomatic women with laparoscopy-confirmed salpingitis were screened for the presence of specific IgG and IgA antibodies to Chlamydia trachomatis by a single antigen (L-2) immunoperoxidase assay. All women were found to have IgG and IgA antibodies to C trachomatis. Six women had positive endocervical cultures for C trachomatis, and one of these had positive cultures from the conjunctiva and fallopian tubes. Serum chlamydial IgA antibodies may serve as markers for active infection with C trachomatis regardless of whether organisms can be identified by culture or direct fluorescent antibody techniques from endocervical or fallopian tube samples.

Antibodies, Bacterial↗

PubMed1988

Prevalence of IgA and IgG antichlamydial antibodies in women in the third trimester of pregnancy.

The prevalence of serum antichlamydial IgA and IgG antibodies was investigated by screening 77 randomly selected patients who were in the third trimester of pregnancy. An indirect immunoperoxidase assay that quantitates IgA and IgG was used for screening. Twenty-five women had both IgA and IgG antibodies; an additional ten women had only IgG antibodies. These findings suggest that greater than 45 percent of pregnant women tested had been exposed to Chlamydia trachomatis, and more than 32 percent had evidence of active infection.

Chlamydia Infections↗

PubMed1988

A comparison of culture, direct fluorescent antibody test, and a quantitative indirect immunoperoxidase assay for detection of Chlamydia trachomatis in pregnant women.

An indirect immunoperoxidase assay that quantitates antichlamydial immunoglobulin G (IgG) and IgA antibodies in serum was compared with endocervical culture and direct fluorescent antibody (MicroTrak) for detection of Chlamydia trachomatis in asymptomatic pregnant women. Of the 64 women tested by the three methods, 22 (34%) had antichlamydial IgG and IgA in their serum. The culture was positive in nine patients (14%) and the MicroTrak was positive in eight (12.5%). All positive cultures were immunoperoxidase-positive. One positive MicroTrak was immunoperoxidase- and culture-negative. Thirteen patients had IgG and IgA antichlamydial antibodies with no organisms detected in the endocervix by culture or by direct fluorescent antibody screen.

Cells, Cultured↗

PubMed1984

Regulation of the oxidative burst of macrophages by lipid mediators.

Macrophages, on stimulation, generate both cyclo-oxygenase and lipoxygenase products of arachidonic acid as well as the acetylated phospholipid, PAF-acether. The latter induces the oxidative burst in C. parvum-activated macrophages, but has little activity on resident macrophages. Mouse macrophages are generally rather insensitive to PAF-acether. Prostaglandin (PG)E2, on the other hand is a potent inhibitor of the macrophage oxidative burst, though its activity is also dependent upon the source of the macrophages and the stimulus used. Several lipoxygenase inhibitors inhibit the oxidative burst of mouse peritoneal macrophages, while other authors have reported stimulatory effects of lipoxygenase products on different macrophage populations. The differential actions of lipoxygenase and cyclo-oxygenase products on the macrophage oxidative burst are reflected by the effect of arachidonic acid on the zymosan induced response of mouse resident peritoneal cells: initial enhancement, followed by prolonged inhibition, the latter being indomethacin-sensitive. While PAF-acether is probably an important initiator of the macrophage oxidative burst in vivo, arachidonic acid modulates the response by a "see-saw mechanism", lipoxygenase products being stimulatory and cyclo-oxygenase products (mainly PGE2) being inhibitory.

Animals↗

PubMed1972