An observational study in Physiologic Venous Dilation and Air Travel, sponsored by Research Inc. Recruiting at 1 site in Colombia. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-08.
Sponsored by Research Inc · Observational
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.
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.
Research Inc is the lead sponsor of 24 studies on the registry; 22 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Adult international medical travelers completing a commercial flight of at least 4 hours to Bogota and undergoing all ultrasound measurements before surgery.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants undergo standardized preflight and postarrival bilateral popliteal vein ultrasound without assignment to a travel intervention.
Other: Commercial Air Travel Exposure · Diagnostic Test: Standardized Bilateral Popliteal Vein Duplex Ultrasound
Participants complete a commercial flight of at least 4 hours to Bogota. Flight duration, connections, cabin class, seat characteristics, movement, fluid intake, alcohol, sedatives, and compression stocking use will be recorded. Linked arm/group(s): Postflight Repeated-Measures Cohort.
After at least 10 minutes of supine rest, the popliteal vein will be imaged at a fixed landmark with minimal probe pressure. Anteroposterior and transverse diameters, cross-sectional area, compressibility, and flow will be recorded in both legs, with three repeated measurements averaged. Linked arm/group(s): Postflight Repeated-Measures Cohort.
Change in Mean Bilateral Popliteal Vein Diameter
At each visit, the mean of three anteroposterior diameter measurements in each leg will be calculated, followed by the mean of both legs. Change from the participant's preflight value will be reported in millimeters and as percent change.
Time frame: Within 24 hours before departure; within 2 hours after arrival at the study site; 24 +/- 2 hours after arrival; and 48 +/- 2 hours after arrival. 1 week
Return of Popliteal Vein Diameter to Baseline
Proportion of participants whose mean bilateral diameter is within plus or minus 10% of their preflight value.
Time frame: 24 +/- 2 hours and 48 +/- 2 hours after arrival. 1 week
Incidental Venous Thrombosis or Abnormal Compressibility
Number and proportion of participants with a new noncompressible venous segment or other finding requiring diagnostic clinical evaluation. This research protocol is not designed as a definitive thrombosis screening examination unless the final duplex protocol is expanded.
Time frame: From preflight baseline through 48 hours after arrival. 1week
Plan to share: No — not contempled in the patient informed consent
Ran from Jan 2024 to primary completion in Sep 2026, 31 months.
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