Variables associated with pulmonary thromboembolism in injured patients: A systematic review

Background: Pulmonary thromboembolism (PTE) is a dangerous complication of traumatic injury, with varied risk profiles and treatment options. This review aims to describe reported incidence and variables associated with PTE among severely injured patients.

Methods: Searches were conducted using PubMed, Cochrane and MEDLINE. Relevant studies were identified by two independent reviewers based on predetermined inclusion criteria. Incidence of PTE was the primary outcome measure. Variables associated with PTE was the secondary outcome measure. The Newcastle-Ottawa Scale was used to assess quality of included studies.

Results: There were eight studies that satisfied inclusion criteria. The diagnosed incidence of PTE in these populations ranged from 0.35 to 24%. The most common variables associated with PTE were pelvic or lower limb injury, chest injury, higher total Injury Severity Score, male sex and age. Variables that were less commonly associated with PTE were previous warfarin use, head injury, high serum lactate, soft tissue injury, more than one operation, more than three days on a ventilator, presence of a subclavian central venous catheter, need for a blood transfusion, systolic blood pressure <90mmHg, abdominal injury, presence of a deep venous thrombosis, inferior vena cava filter placement and isolated liver spleen or spinal injuries.

Conclusions: The reported incidence of PTE after major trauma is variable and dependent on inclusion criteria, diagnostic criteria and study design. Identified variables differed to those reported for venous thromboembolism in other populations. It is difficult to predict populations at risk of clinically significant PTE following injury using available evidence. Further studies linked to patient-specific variables will assist in more precise risk-stratification and interventions.