Evaluation of the appropriateness of frozen plasma usage after introduction of prothrombin complex concentrates: a retrospective study.

BACKGROUND: Prothrombin complex concentrates (PCCs) can be used instead of frozen plasma (FP) transfusion to reverse the effect of warfarin. Audits have demonstrated over usage of FP transfusions even before the introduction of PCC. The objective of this study was to determine the appropriateness of current FP transfusion practice in the current era since the introduction of PCCs. METHODS: A retrospective cohort study of consecutive patients receiving FP over 3 months was carried out. Each episode of FP use over a 24-h period was adjudicated independently by two reviewers as appropriate (consistent with Canadian/AABB guidelines), appropriate but inconsistent with guidelines or inappropriate. Discrepancies were resolved by a third reviewer. Use of FP to reverse warfarin was considered inappropriate. FP usage from previous years was assessed as baseline. RESULTS: During the study period, 111 FP transfusions were administered. 74.8% of FP usage occurred in the ICU. The proportion of FP transfusions that were deemed appropriate, inconsistent yet appropriate or inappropriate were 33/89 (37.1%), 16/89 (18.0%) and 40/89 (44.9%), respectively, when use of FP for therapeutic plasma exchange was excluded. The most common reasons for inappropriate use were the absence of bleeding with an increased INR or warfarin reversal. CONCLUSION: Our study is the first to audit FP transfusions in the post-PCC era in Canada. FP usage remains inappropriately high in INR prolongation without another indication or to reverse warfarin. Targeted interventions to reduce FP usage in the future should focus on the ICU and on education about warfarin reversal.

Weight-adjusted tinzaparin for the prevention of venous thromboembolism after bariatric surgery.

Essentials The optimal dose and duration of thromboprophylaxis after bariatric surgery are unclear. We evaluated the safety of weight-adjusted tinzaparin prophylaxis in 1212 patients. In-hospital rates of venous thromboembolism and major bleeding were 0.2% and 1.8% respectively. In a sub-set of patients, trough anti-Xa levels did not show excessive anticoagulant activity. SUMMARY: Background Patients undergoing bariatric surgery are at moderate to high risk of venous thromboembolism (VTE). The optimal dose and duration of anticoagulant prophylaxis is uncertain. Objective To evaluate the safety of extended-duration weight-adjusted tinzaparin after bariatric surgery. Patients/methods We conducted a single-center retrospective cohort study of consecutive patients undergoing bariatric surgery who received weight-adjusted tinzaparin 4500-14 000 IU daily (75 IU kg-1 rounded to the nearest prefilled syringe) for 10 days after surgery (7-9 days post-hospital discharge). Primary safety outcomes were the frequency of VTE and major bleeding within 30 days of surgery in patients receiving at least one dose of tinzaparin. Results A total of 1279 patients undergoing bariatric surgery between July 2009 and December 2012 were reviewed, of whom 1212 received weight-adjusted tinzaparin. Safety outcomes were collected for 819 patients at 30 days, and for 1212 patients in-hospital only. The median age was 45.0 years, median weight was 130.0 kg and 98.8% of patients underwent gastric bypass or sleeve gastrectomy. In patients completing 30 days of follow-up, VTE occurred in 4/819 (0.5%) and major bleeding occurred in 13/819 patients (1.6%). In-hospital rates of VTE and major bleeding during surgical admission were 3/1212 (0.2%) and 22/1212 (1.8%), respectively. Conclusions Extended thromboprophylaxis with weight-adjusted tinzaparin appears to be a safe strategy after bariatric surgery, with low rates of postoperative VTE and major bleeding.

A high-sensitivity, low-cost, voltage-to-frequency integrator for laboratory strip-chart recorders.

In is often desirable to obtain the integral of a signal whose amplitude is rapidly fluctuating with time. For example, the signal produced by a hydrogen flame photometer to quantify the sodium content in a sodium chloride respirator quantitative fit test instrument is representative of the type of signal that is frequently recorded on a strip-chart recorder, but whose integral is tedious to calculate. A long-term precision integrator was designed that utilizes a commercially available voltage-to-frequency integrated circuit module. The integrator is capable of integrating a 0-10 V signal for time periods greater than 1 h with an overall accuracy of 0.1%. The integrator can be built from commercially available components for less than $600.

Chemically sensitive field-effect transistor to detect organophosphorous compounds and pesticides.

A critical assessment is made concerning the application of a chemically sensitive field-effect transistor (CHEMFET) to detect organophosphorous compounds and pesticides in the ambient environment at the ppb concentration level. A performance analysis of the four types of CHEMFET structures -- enzyme-coupled, galvanostatic, catalytic, and work-function -- is presented. The integration of chemically sensitive polymers with the field-effect transistor structure is addressed. The focus of the assessment deals with practical performance criteria such as sensitivity, response time, reversibility, shelf-life, operational life, and lifetime.

Comparison of respirator protection factors measured by two quantitative fit test methods.

A comparison of measured respirator protection factors for a di-2-ethylhexyl phthalate (liquid aerosol challenge) respirator quantitative fit test method is made with a complementary sodium chloride (solid aerosol challenge) method. The United States Army XM-29 chemical warfare defense respirator was used in this evaluation. A subject pool of twelve individuals (two female and ten male) were fitted and tested on both respirator quantitative fit test methods on ten different occasions. An exercise protocol of six different breathing and head movement maneuvers was used in each test. The purpose of the comparison was to determine if there is a difference between the two fit test methods. The di-2-ethylhexyl phthalate method showed a significant order-interaction effect with respect to the exercise sequence and whether it preceded or followed testing with sodium chloride. The sodium chloride method did not show a similar phenomenon, and consistently measured smaller protection factors compared to the di-2-ethylhexyl phthalate method. It appears that the sodium chloride method is more sensitive.