Study of the Effects of Commercial Air Travel on the Lungs

Study of the Effects of Commercial Air Travel on Pulmonary Artery Pressure in Healthy Passengers and in a Patient With Chuvash Polycythaemia

The study hypothesis is that commercial air travel causes an increase in the blood pressure in the lungs (pulmonary artery pressure) that can be clinically relevant. Portable echocardiography (heart ultrasound) now offers a non-invasive means of studying this in-flight.

Study Overview

• Status: Completed
• Conditions: Healthy Volunteers; Chuvash Polycythaemia
• Intervention / Treatment: Other: Commercial airline flight

Detailed Description

In a commercial airliner flying at high altitude, the reduced cabin air pressure means that all passengers are exposed to slightly lowered oxygen levels ('hypoxia') equivalent to an altitude of approximately 5,000 to 8,000 ft. Although mild, this hypoxia is sufficient to stimulate some of the body's protective responses (eg changes in breathing and in hormonal secretion) and can be dangerous for passengers with heart or lung disease, who must breathe supplementary oxygen in-flight or may even be prohibited from flying because of the risks of hypoxia.

It is well known that severe hypoxia results in constriction of blood vessels in the lungs (a phenomenon called hypoxic pulmonary vasoconstriction), which in turn causes an increase in the blood pressure in the lungs ('pulmonary arterial pressure'). Unlike other physiological responses to hypoxia, this is often harmful and frequently leads to pulmonary hypertension and right heart failure (eg in some lung diseases and at high altitude). Even a modest increase in pulmonary arterial pressure could be clinically important in some airline passengers with heart/lung disease, as it may exacerbate their condition. However, it is not known whether the mild hypoxia experienced in an aircraft cabin is able to cause an increase in pulmonary artery pressure. Limited evidence suggests that it might - for example, there have been reports of passengers acutely developing new right heart failure in-flight, and data from animal studies also support this possibility.

This study aims to establish the effect of mild aircraft cabin hypoxia on pulmonary arterial pressure in healthy passengers and also in a patient with Chuvash polycythaemia. In this rare genetic disease, cellular responses to hypoxia are 'switched on' to some extent even during normoxia, causing increased red blood cell production. Affected individuals usually present with symptoms of polycythaemia in early adulthood and are typically asymptomatic following treatment with therapeutic venesection. Importantly, affected individuals have exaggerated acute hypoxic pulmonary vasoconstriction which may place them at risk of pulmonary hypertensive responses during air travel.

• Study Type: Observational
• Enrollment (Actual): 9

Contacts and Locations

Study Locations

• United Kingdom
  • Oxford, United Kingdom, OX13PT
    • University of Oxford

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patient with Chuvash polycythaemia recruited from previous study participants with the disease.

Description

For healthy volunteers:

Inclusion Criteria:

• suitable for echocardiographic measurements
• in good health

Exclusion Criteria:

• any significant medical condition

For patient with Chuvash polycythaemia:

Inclusion Criteria:

• diagnosis of Chuvash polycythaemia
• suitable for echocardiographic measurements

Exclusion Criteria:

• any other significant medical condition
• pulmonary hypertension
• uncontrolled erythrocytosis

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Healthy volunteers	Other: Commercial airline flight; Normal scheduled passenger flight
Chuvash polycythaemia	Other: Commercial airline flight; Normal scheduled passenger flight

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systolic pulmonary artery pressure	The primary outcome measure is the effect of commercial air travel on systolic pulmonary artery pressure assessed by in-flight portable Doppler echocardiography.	In-flight

Collaborators and Investigators

• Sponsor: University of Oxford
• Investigators: Principal Investigator: Thomas Smith, MBBS DPhil FRCA, University of Oxford

Study record dates

Study Major Dates

• Study Start: May 1, 2011
• Primary Completion (Actual): June 1, 2011
• Study Completion (Actual): June 1, 2011

Study Registration Dates

• First Submitted: August 18, 2011
• First Submitted That Met QC Criteria: August 18, 2011
• First Posted (Estimate): August 19, 2011

Study Record Updates

• Last Update Posted (Estimate): August 19, 2011
• Last Update Submitted That Met QC Criteria: August 18, 2011
• Last Verified: August 1, 2011

More Information

Terms related to this study

• Keywords: Pulmonary hypertension; Pulmonary artery pressure; Hypoxic pulmonary vasoconstriction; Air travel; Aircraft cabin hypoxia
• Additional Relevant MeSH Terms: Hematologic Diseases; Polycythemia
• Other Study ID Numbers: Oxford in-flight 2011