Overview
This prospective repeated-measures study will evaluate how long popliteal vein dilation persists after international commercial air travel to Bogota. Adult medical travelers will undergo standardized bilateral popliteal vein ultrasound within 24 hours before departure, within 2 hours after arrival, and at 24 and 48 hours after arrival, all before surgery. The primary outcome is change in mean bilateral popliteal vein diameter over time.
Description
Eligible international travelers will complete a standardized preflight ultrasound and three postarrival examinations before surgery or intravenous fluid therapy. Each scan will be performed after a fixed resting period using the same popliteal landmark, minimal transducer pressure, and triplicate bilateral measurements. Flight duration, class, seat characteristics, movement, fluid intake, compression stocking use, and venous risk factors will be recorded. Mixed-effects analysis will estimate the postflight diameter and cross-sectional-area trajectory and the proportion returning to within 10% of baseline by 48 hours.
Eligibility
Inclusion Criteria:
- Age 18 to 65 years.
- International commercial flight to Bogota with total airborne time of at least 4 hours.
- Preflight baseline ultrasound obtained within 24 hours before departure using the standardized protocol.
- Arrival ultrasound completed within 2 hours after reaching the study site and before surgery or intravenous fluid therapy.
- Availability for 24-hour and 48-hour examinations.
- Written informed consent.
Exclusion Criteria:
- Known current deep venous thrombosis or pulmonary embolism.
- Therapeutic anticoagulation at enrollment.
- Major lower-extremity venous surgery, active leg infection, or condition preventing popliteal ultrasound.
- Surgery, prolonged immobilization, or substantial intravenous fluid administration before completion of the 48-hour measurement.
- Pregnancy.
- Nondiagnostic baseline examination or inability to reproduce the landmark.
