Aim Heparin is used in patients who require anticoagulation for treatment or prevention of thrombosis. Much of the evidence for anticoagulation with both unfractionated and low molecular weight heparin (LMWH) is derived from adult practice.
This audit aimed to evaluate the accuracy of tinzaparin dosing and monitoring, and thus the provision of appropriate anticoagulation for treatment and prevention of thrombosis in paediatric patients. This was in line with trust clinical guidelines: ‘Low molecular weight heparin guideline: paediatrics (treatment and prophylaxis)’.1
Method Paediatric patients prescribed Tinzaparin between November 2017 and December 2018 were retrospectively identified from finance reports. Patient notes, which documented Tinzaparin indication, dosing and monitoring parameters (Anti-Xa levels) were accessed. Findings were recorded in a data collection questionnaire, derived from set standards, to identify if the corresponding local guidelines had been adhered to.1 Subsequent statistical analysis was used to highlight trends within the data collection.
Results 88% (21/24) of paediatric patients were dosed accurately according to Tinzaparin indication; treatment or prophylaxis and patient weight as per guidelines. One anomaly was dosed according to local guidelines for adult patients, whilst a second and third were initiated on prophylactic rather than treatment dosing. Only 11% (3/24) of paediatric patients had their Anti-Xa level recorded at the correct time interval of 4 hours post dose. Evaluation of this data confirmed that for prophylactic regimens Anti-Xa levels were recorded in 7% (1/16) of patients, compared to 33% (3/8) for treatment regimens. Although Anti-Xa levels were recorded throughout 100% (8/8) of tinzaparin treatment regimens, 66% (5/8) failed to be recorded within four hours post first and second dose; a guideline requirement. These ‘random’ Anti-Xa levels commonly lay outside of the desired Anti-Xa level range highlighted in the guideline and subsequent dose adjustment meant that dosing regimens deviated from guidelines in an attempt to get the Anti-Xa levels within range. For regimens that lay outside the desired range but that were then adjusted in accordance with a dose adjustment tool within the guideline, all patients achieved the desired range efficiently and effectively, confirming that following the guideline achieves desirable results.
Conclusions It was clear that Tinzaparin was initiated appropriately in the majority of paediatric patients in accordance with patient age and weight, that an attempt was made to monitor patients receiving a treatment dose regimen and that some effort was made to maintain these levels within the desired range. The main issue raised by this audit was the lack of adequate Tinzaparin monitoring throughout prophylactic dosing, thus highlighting an opportunity to educate and communicate the guideline to health care professionals within this field of practice to encourage effective treatment and prophylaxis of thrombosis. Raising awareness for the need of adequate documentation within patient notes to explain omitted dosing would also guide healthcare professionals involved in patient care to make informed decisions and avoid unnecessary alterations to treatment plans.
Lumb P, Fletcher P. 2017. Low Molecular Weight Heparin Guideline: Paediatrics (Treatment and Prophylaxis). Imperial College NHS Trust.
Medicines.org.uk. 1997. Tinzaparin sodium Syringe10,000IU/ml - Summary of Product Characteristics (SmPC) - (eMC). [online] Available at: https://www.medicines.org.uk/emc/product/2022/smpc [Accessed 19 Mar. 2019]
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