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 2026-09-09.
Sponsored by Research Inc · Observational
This prospective cohort study will compare popliteal vein diameter changes in international travelers who independently fly to Bogota in premium business/first class or economy class. Standardized bilateral ultrasound will be performed before flight, within 2 hours after arrival, and at 24 and 48 hours. The primary outcome is the adjusted between-group difference in change from preflight diameter to arrival. Travel behavior and venous-risk confounders will be measured prospectively.
Travelers with documented premium or economy itineraries will be enrolled before departure. Bilateral popliteal vein diameter and cross-sectional area will be measured using a standardized ultrasound protocol before flight and three times after arrival, all before surgery. Actual seat characteristics, flight duration, connections, ambulation, fluid intake, alcohol, sedatives, and compression stocking use will be recorded. Mixed-effects and propensity-weighted analyses will compare the magnitude and persistence of dilation between cabin groups while acknowledging that cabin class is not randomized.
Adult international medical travelers with prebooked premium business/first-class or economy-class itineraries of at least 4 hours.
Exclusion Criteria:
Participants who independently booked and completed the qualifying itinerary in business or first class.
Other: Premium Cabin Air Travel Exposure · Diagnostic Test: Standardized Bilateral Popliteal Vein Ultrasound
Participants who independently booked and completed the qualifying itinerary in economy or basic economy class.
Other: Economy Cabin Air Travel Exposure · Diagnostic Test: Standardized Bilateral Popliteal Vein Ultrasound
Preexisting travel exposure defined by the cabin actually flown. Seat pitch, recline, lie-flat capability, aisle/window position, and ambulation opportunities will be recorded. Linked arm/group(s): Premium Cabin Travelers.
Preexisting economy-cabin exposure with documentation of seat characteristics, position, movement, hydration, and other travel behaviors. Linked arm/group(s): Economy Cabin Travelers.
Triplicate anteroposterior and transverse diameter and cross-sectional-area measurements in both legs after a standardized resting period, with compressibility and flow assessment. Linked arm/group(s): Premium Cabin Travelers, Economy Cabin Travelers.
Between-Cabin Difference in Change in Mean Bilateral Popliteal Vein Diameter
Difference between premium and economy groups in the participant-level change from preflight baseline to arrival. Diameter will be the mean of triplicate anteroposterior measurements in both legs and will be reported in millimeters.
Time frame: Within 24 hours before departure and within 2 hours after arrival at the study site. 3 days
Incidental Venous Thrombosis or Abnormal Compressibility
Number and proportion with a new abnormality requiring immediate clinical assessment.
Time frame: From preflight baseline through 48 hours after arrival. 3 days
Plan to share: No — not contempled in the patient informed consent
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