Implementation of a molecular genotyping protocol for patients with warm autoantibodies.

BACKGROUND: Warm autoantibodies (WAAs) cause delays and additional expenses while determining suitable products when using a traditional protocol (TP). In 2013, Carter BloodCare Immunohematology Reference Laboratory (IRL) introduced a molecular protocol (MP) for patients with WAAs. STUDY DESIGN AND METHODS: Retrospective review of records for samples referred to the IRL from November 2004 to September 2020, was performed. Referrals, alloantibody(ies), gender, and age were recorded. Additionally, the count of common clinically significant antigens needed for phenotypically matched red blood cells (RBCs) were recorded for patients in MP. To further analyze charges and time spent testing patients with WAAs, 300 patients were selected. RESULTS: Analysis of average charges to the referring hospital and time spent testing in the IRL determined savings at two or more referrals. Overall, 219 of 300 (73%) of patients in the study met or exceeded the number of referrals. Further analysis shows that while the population of patients with WAA (n = 300) shared similar demographics, there was a statistically significant difference between the average time testing patients in TP (M = 264.18, SD = 15.06) and MP (M = 156.00, SD = 90.37), t(157) = 14.46, p < .001, 95% confidence interval [CI] (93.41-122.97). Additionally, the assumption that each patient received two RBCs per referral provided no statistically significant difference between average charges to the hospitals of patients in TP (M = 1222.58, SD = 165.69) and MP (M = 1269.78, SD = 433.52), t(192) = -1.25, p = .214, 95% CI (-121.95-27.54). CONCLUSION: The MP has been effective in saving time spent testing patients with WAAs, which benefits referring hospitals, patients, and IRLs. Charges for prophylactic phenotypically matched blood were negligible and a MP would alleviate some of the current laboratory difficulties while providing safe products to patients.

Washed RBCs prevent recurrent acute hypotensive transfusion reactions.

OBJECTIVES: To examine whether a liver transplant patient, who was not taking an angiotensin-converting enzyme inhibitor and developed two episodes of hypotension with systolic pressure in the 50s within minutes of starting an RBC transfusion, may have had a disturbance in the production and metabolism of bradykinin and des-Arg(9)-BK. METHODS: All patient information was obtained by reviewing the electronic medical record, the transfusion service database, and transfusion reaction investigation records. RESULTS: The blood pressure returned to normal once the transfusions were discontinued. In an effort to mitigate the acute hypotension, the blood products were washed. Subsequently, the patient received three additional packed RBC transfusions without further incidents of hypotension. CONCLUSIONS: Our experience suggests that washing the products was an acceptable and effective preventative measure to avoid further acute hypotensive transfusion reactions in patients unable to metabolize these vasodilators present in the donor units.

Methods of characterizing the distribution of exhaust emissions from light-duty, gasoline-powered motor vehicles in the U.S. fleet.

Mobile sources significantly contribute to ambient concentrations of airborne particulate matter (PM). Source apportionment studies for PM10 (PM < or = 10 microm in aerodynamic diameter) and PM2.5 (PM < or = 2.5 microm in aerodynamic diameter) indicate that mobile sources can be responsible for over half of the ambient PM measured in an urban area. Recent source apportionment studies attempted to differentiate between contributions from gasoline and diesel motor vehicle combustion. Several source apportionment studies conducted in the United States suggested that gasoline combustion from mobile sources contributed more to ambient PM than diesel combustion. However, existing emission inventories for the United States indicated that diesels contribute more than gasoline vehicles to ambient PM concentrations. A comprehensive testing program was initiated in the Kansas City metropolitan area to measure PM emissions in the light-duty, gasoline-powered, on-road mobile source fleet to provide data for PM inventory and emissions modeling. The vehicle recruitment design produced a sample that could represent the regional fleet, and by extension, the national fleet. All vehicles were recruited from a stratified sample on the basis of vehicle class (car, truck) and model-year group. The pool of available vehicles was drawn primarily from a sample of vehicle owners designed to represent the selected demographic and geographic characteristics of the Kansas City population. Emissions testing utilized a portable, light-duty chassis dynamometer with vehicles tested using the LA-92 driving cycle, on-board emissions measurement systems, and remote sensing devices. Particulate mass emissions were the focus of the study, with continuous and integrated samples collected. In addition, sample analyses included criteria gases (carbon monoxide, carbon dioxide, nitric oxide/nitrogen dioxide, hydrocarbons), air toxics (speciated volatile organic compounds), and PM constituents (elemental/organic carbon, metals, semi-volatile organic compounds). Results indicated that PM emissions from the in-use fleet varied by up to 3 orders of magnitude, with emissions generally increasing for older model-year vehicles. The study also identified a strong influence of ambient temperature on vehicle PM mass emissions, with rates increasing with decreasing temperatures.