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Biomedical subjects

R T O'Kell

Publications and source records attributed to R T O'Kell.

At least 19 recordsLinked to original sources
PubMed1994

Screening for gestational diabetes mellitus with a reflectance photometer: accuracy and precision of the single-operator model.

OBJECTIVE: To investigate the accuracy and precision of a recent-generation reflectance photometer, Accu-Chek III, for gestational diabetes mellitus screening with a single operator. METHODS: Four hundred ten paired capillary and serum glucose samples collected prospectively were evaluated by a reflectance photometer and a glucose oxidase method (Beckman), respectively, during routine gestational diabetes mellitus screening with a single operator. RESULTS: The mean Accu-Chek III result was 12% greater than serum glucose oxidase (115.5 +/- 1.4 and 103.4 +/- 1.3 mg/dL, respectively). A serum glucose level of at least 135 mg/dL by glucose oxidase produced sensitivity and specificity of 0.81 and 0.68, respectively. At 155 mg/dL, the Accu-Chek III sensitivity was 0.81 and specificity 0.74, and the method produced fewer false-positive results (37 of 410 [9.0%] versus 41 of 410 [10%]) than a 135-mg/dL serum cutoff. Adjusting the Accu-Chek III threshold by two times the coefficient of variation resulted in the same number of false positives as the Beckman technique at 135 mg/dL. The receiver operating characteristic curve cutoff for the venous value of 135 mg/dL was an Accu-Chek III value of 141 mg/dL. Linear regression analysis predicted y = 20.6 + 0.919x, r = 0.838. The mean coefficient of variation was 3.9%. CONCLUSIONS: The Accu-Chek III produced accurate and precise gestational diabetes mellitus screening results with a single operator. Because capillary blood is a combination of arterial and venous blood, an Accu-Chek III cutoff of 155 mg/dL may be more appropriate for screening, considering the 10-15% higher capillary glucose level in the fed state. An Accu-Chek III cutoff of 155 mg/dL produced a higher specificity than venous serum at 135 mg/dL, with no decrease in sensitivity.

Adult↗
PubMed1994

Carbohydrate sources for gestational diabetes mellitus screening. A comparison.

One hundred eight patients were prospectively randomized to receive 50 g of a glucose polymer, d-glucose or a candy bar during a one-hour gestational diabetes mellitus (GDM) screening. The polymer had a mean serum glucose similar to that of d-glucose, with significantly fewer side effects, allowing an increased rate of examination completion. The candy bar produced a significantly lower mean serum glucose but had the highest rating for flavor. The polymer was an inexpensive and well-tolerated alternative for GDM screening, while the use of a candy bar needs more study.

Adult↗
PubMed1990

Hyperkalemia after irradiation of packed red blood cells: possible effects with intravascular fetal transfusion.

Plasma potassium, calcium, and albumin concentrations in irradiated blood, and in fetal blood before and after transfusion, were measured. Dangerously high plasma potassium levels were observed in some units of irradiated packed red blood cells (range, 13.9 to 66.5 mEq/L; mean, 44.7 mEq/L) and could be one possible explanation for the high incidence of fetal arrhythmia associated with fetal intravascular transfusion. There are many factors operative in the preparation of irradiated packed red blood cells that may predispose to high potassium levels: the age of the red blood cells, the number of procedures used to concentrate the blood, the duration of time elapsed from concentration, the duration of time elapsed from irradiation, and the hematocrit. Use of fresh blood, avoidance of multiple packing procedures, limiting the hematocrit in the donor unit to less than or equal to 80%, and minimizing the time between concentration, irradiation and transfusion may minimize the potassium levels, and therefore making an additional washing procedure unnecessary.

Arrhythmias, Cardiac↗
PubMed1983

Data regarding blood drawing sites in patients receiving intravenous fluids.

Intravenous fluids were infused into the forearms of 18 volunteers. Baseline hematologic and serum biochemical profiles were obtained from each volunteer prior to starting the IV. After the intravenous fluids had infused for 30 minutes, blood was drawn from the opposite arm, and above and below the IV in the same arm. The intravenous fluids were then stopped, and after waiting two minutes, another blood sample was drawn from the IV needle. The deviation from the baseline value was determined for each analyte by sampling site for each volunteer and the mean deviation was calculated for each analyte from each sample site. Drawing blood from above the infusing IV line resulted in a dilutional effect for most of the analytes. Most analytes were not affected when blood was drawn from the other sites. Serum glucose and phosphorus had mean deviations greater than two standard deviations from the baseline, regardless of where they were drawn. Serum glucose was the only analyte with values higher than the baseline values. We recommend that serum biochemical and hematologic profiles not be drawn above an infusing IV, but should be drawn from the opposite arm or below the IV while it is infusing or out of the IV needle after the intravenous fluids have been stopped for two minutes.

Adult↗
PubMed1983

Clinical evaluation of Eastman Kodak's Ektachem 400 Analyzer.

We evaluated the performance of the Kodak Ektachem 400 Analyzer in a 16-week clinical trial. We assessed four potentiometric tests and nine colorimetric tests for precision and correlation with results obtained some other commonly used instruments (Technicon SMA II and C800 System, Du Pont aca II, and Baker CentrifiChem). The comparison was favorable for all tests except albumin, sodium, and carbon dioxide. The reagents are stable. Little refrigerator storage space is needed. The computer system and the modular component design of the Ektachem 400 Analyzer make operation, troubleshooting, and preventive maintenance relatively easy.

Adult↗
PubMed1981

Comparison of fresh-frozen plasmas thawed in a microwave oven and in a 37 degrees C water bath.

Fresh-frozen plasma can be thawed rapidly in a microwave oven without loss of function of coagulation factors and with no adverse effects to the patients. In patients receiving fresh-frozen plasma thawed in a microwave oven, the prothrombin time was decreased by an average of 2.9 sec per unit, and the activated partial thromboplastin time was decreased by an average of 9.6 sec per unit, compared with decrease of 2.6 sec and 6.3 sec for patients receiving fresh-frozen plasma thawed in a water bath at 37 degrees C.

Blood Preservation↗
PubMed1980

New brain-cutting box: its use in computerized axial tomographic scan and autopsy brain section correlation.

A new brain-cutting box aids in the sectioning of autopsied brains along planes that correspond to computerized axial tomographic (CT) scans levels. There are two plastic boxes, one inside the other. The inner one has a platform slanted at a 15 degree angle from the horizontal plane. The brain, resting on this platform, can be raised by elevating the inner box and can be sectioned along the horizontal upper free edges of the outer box. The resulting sections, cut at appropriate intervals, correspond to CT scans. This box has numerous advantages over existing brain-cutting devices.

Autopsy↗