Comparison of Subcutaneous and Intravenous Heparin Administration Methods for the Prevention of Venous Thromboembolism in the Intensive Care Unit

Comparison of subcutaneous and intravenous heparin injection methods (5000 units every 12 hours) on the prevention of venous thromboembolism and platelet changes in intensive care unit patients.

A parallel-group, double-blind, randomized clinical trial with a 1:1 allocation ratio on 112 patients. Random Allocation Software was used for randomization.

The study will be conducted in the intensive care unit of Shahid Mohammadi Hospital, Bandar Abbas. After obtaining informed consent, 112 patients will be randomly assigned. Coagulation indices (PT, INR, aPTT) and platelet count will be recorded every 3 days. For signs suspicious of Venous Thromboembolism, Doppler ultrasound or CT angiography will be performed.

Patients admitted to the intensive care unit (ICU) of Shahid Mohammadi Hospital, Bandar Abbas, who were eligible for heparin prophylaxis (based on Wells or Caprini score ≥3 and no contraindications) were enrolled in the study. Exclusion criteria included allergy to heparin, severe thrombocytopenia (platelets <50,000), active bleeding, severe renal failure (CrCl <30 mL/min), lack of informed consent, and pregnancy.

The first group received subcutaneous heparin (5000 units every 12 hours) and the second group received intravenous heparin (5000 units initial bolus + continuous infusion adjusted to maintain target aPTT). All patients received standard ICU care including hemodynamic monitoring, oxygen therapy, and basic VTE prophylaxis.

Primary outcome: occurrence of venous thromboembolism (Venous Thromboembolism) and changes in coagulation parameters (platelet count, PT, INR, aPTT). Secondary outcomes: incidence of major bleeding, thrombocytopenia, length of ICU stay, mortality, and lower limb size difference.

This clinical trial will use simple randomization with an individual randomization unit. Patients admitted to the intensive care unit (ICU) of Shahid Mohammadi Hospital, Bandar Abbas, who are eligible based on inclusion criteria (such as ICOPER criteria and no contraindication to heparin), will be allocated in a 1:1 ratio to two groups of subcutaneous heparin injection (5000 units/m2, twice daily) and intravenous heparin injection (5000 units/m2, twice daily). Random Allocation Software was used to generate the randomization sequence. Allocation concealment is ensured through segregation of responsibilities of the research team (separation of the enroller from the allocator), limited access control to the randomization sequence, and complete documentation of the process to minimize the possibility of selection bias.

This study is a double-blind clinical trial in which patients, ICU attending physicians, nursing staff (except the injecting nurse), and outcome assessors (including the person performing the Doppler ultrasound, the clinical assessment of VTE symptoms, and the final judgment of VTE diagnosis) will be unaware of the prescribed heparin injection method (subcutaneous or intravenous) and patient allocation group. Preparation and administration of drugs will be performed by the injecting nurse who is not involved in the outcome assessment and clinical judgment. Heparin vials and syringes are provided with coded labels (A or B) without indicating the actual injection method. The allocation code will be kept in sealed envelopes and will not be opened until the end of the study and the completion of data analysis, except in emergencies. Data collection is performed by a research assistant or independent nurse who is unaware of patient allocation, and only the nurse responsible for preparing and administering the drug and the person responsible for randomization (who are not involved in enrollment and outcome assessment) will be aware of the allocation. This design minimizes the potential for performance bias and detection bias.

En Still undecided - no release schedule yet.