Screening duplex ultrasonography in neurosurgery patients does not correlate with a reduction in pulmonary embolism rate or decreased mortality

Elevated risk of venous thromboembolism among post-traumatic brain injury patients requiring pharmaceutical immobilization

Traumatic brain injury (TBI) patients are known to have a high rate of venous thromboembolism (VTE), and additional neuromuscular blockade or barbiturate coma therapy has the theoretical risk of exacerbating baseline hemostasis and elevating the incidence of thromboembolic events. We conducted a single-institution retrospective review of patients surviving severe TBI, as determined by need for intracranial pressure (ICP) monitoring, who further required paralytics or barbiturate therapy to maintain ICP control. Patients were administered VTE prophylaxis as clinically appropriate. Predictors for VTE were subsequently determined with univariate and logistic multivariate regression analyses. The main cohort includes 144 patients, 34 of whom received pharmaceutical immobilization for ICP control. Mean ISS and GCS at intake were 31.9 and 5.2, respectively. Among those receiving vs not-receiving paralytics and/or barbiturate therapy, there was a statistical difference of 12/34 (35.3%) vs 18/110 (16.4%, p = 0.0280) in VTE events, at a mean time greater than two weeks from the time of trauma. Multivariate logistics regression indicated 3.2 times increased odds of developing a VTE (log odds = 1.17, p = 0.023). No pediatric patients were positive for an event (0/12 vs 7/22, p = 0.0356), and infections were only documented among those with VTE (0/22 vs 4/12, p = 0.0107). Overall, paralytics and barbiturate therapy were correlated with a higher incidence of VTE among TBI patients. Although the need for ICP control will outweigh an increase in thromboembolic risk, there is value for increased surveillance and screening during the prolonged inpatient stay of these patients.

Surveillance or no surveillance ultrasonography for deep vein thrombosis and outcomes of critically ill patients: a pre-planned sub-study of the PREVENT trial

PURPOSE

We examined the association between surveillance for deep vein thrombosis (DVT) among medical-surgical critically ill patients by twice-weekly ultrasonography and 90-day all-cause mortality.

METHODS

This was a pre-planned sub-study of the Pneumatic Compression for Preventing Venous Thromboembolism (PREVENT) trial (Clinicaltrials.gov: NCT02040103) that compared addition of intermittent pneumatic compression (IPC) to pharmacologic prophylaxis versus pharmacologic prophylaxis alone. The surveillance group included enrolled patients in the trial, while the non-surveillance group included eligible non-enrolled patients. Using logistic regression and Cox proportional hazards models, we examined the association of surveillance with the primary outcome of 90-day mortality. Secondary outcomes were DVT and pulmonary embolism (PE).

RESULTS

The surveillance group consisted of 1682 patients and the non-surveillance group included 383 patients. Using Cox proportional hazards model with bootstrapping, surveillance was associated with a decrease in 90-day mortality (adjusted HR 0.75; 95% CI 0.57, 0.98). Surveillance was associated with earlier diagnosis of DVT [(median 4 days (IQR 2, 10) vs. 20 days (IQR 16, 22)] and PE [median 4 days (IQR 2.5, 5) vs. 7.5 days (IQR 6.1, 28.9)]. There was an increase in diagnosis of DVT (adjusted HR 5.49; 95% CI 2.92, 13.02) with no change in frequency in diagnosis of PE (adjusted HR 0.56; 95% CI 0.19, 1.91).

CONCLUSIONS

Twice-weekly surveillance ultrasonography was associated with an increase in DVT detection, reduction in diagnostic testing for non-lower limb DVT and PE, earlier diagnosis of DVT and PE, and lower 90-day mortality.

TRIAL REGISTRATION

The PREVENT trial is registered at ClinicalTrials.gov, ID: NCT02040103. Registered on 3 November 2013; Current controlled trials, ID: ISRCTN44653506. Registered on 30 October 2013.

Point-of-care ultrasound for deep venous thrombosis of the lower limb

The incidence and morbidity of deep venous thrombosis (DVT) and pulmonary embolus are high. Although efforts to increase screening for DVT have been recommended, this is limited by resources. Venous duplex ultrasound has replaced venography as the first-line investigation of choice for DVT, increasing availability and reducing patient exposure to radiation and intravenous contrast. Furthermore, an abbreviated ultrasound where DVT is inferred from incomplete venous compressibility has an equivalent accuracy to venous duplex, requiring less time and training enabling its widespread use by emergency, critical care and anaesthesia clinicians. In this review, the evolution and method of lower limb venous compression ultrasound is described along with evidence for its use in patients at high risk for DVT in these clinical settings.