The DETECT randomized controlled trial addresses the question of whether surveillance ultrasound in critically ill patients by facilitating DVT detection reduces the incidence of PE and lowers all-cause 90-day mortality. The primary outcome is 90-day all-cause mortality.

This is an open-label multicenter multinational randomized-controlled trial. All patients admitted to ICU will be screened within the first 48 hours of ICU admission for eligibility. Subjects who meet all criteria for enrollment will be randomized via a password-protected, secure website using a variable-size block concealed computer-generated randomization procedure. Patients will be allocated to twice weekly bilateral lower limb ultrasound or standard care (control) in a 1:1 ratio.

Inclusion criteria

1. Medical, surgical or trauma ICU patients ≥18 years old.
2. Patients who are expected to stay in the ICU more than 2 calendar days (unlikely to be discharged out of ICU on the day of admission or on the next day).

Exclusion Criteria

1. Patients with DVT or PE diagnosed within the last year.
2. Patients receiving chronic systemic anticoagulation.
3. Patients who have received up to the time of ICU admission or are receiving therapeutic doses of anticoagulation with UFH, LMWH, or other anticoagulants.
4. Inability or contraindication to obtain adequate ultrasound on the lower extremities (Burns in the lower extremities, lacerations, active skin infection, & ischemic limb in the legs, large dressings in the thighs that prevent adequate ultrasounds OR amputated foot or leg on one or two sides)
5. Patients with Inferior Vena Cava (IVC) Filter.
6. Known or suspected pregnancy.
7. Limitation of life support, life expectancy <7 days or palliative care.
8. Previously enrolled in DETECT trial within the last 180 days.
9. Enrolled in another trial for which co-enrolment is not approved.

The data supporting this study's findings will be available from the corresponding author upon reasonable request as per the regulations of King Abdullah International Medical Research Center (KAIMRC).

After the publication of the main manuscript (Primary outcome analysis)

Proposal that describes planned analyses must be submitted along with a data sharing agreement