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LUNG TRANSPLANTATION

NARROWING PRECISION

If we want to talk about “optimal preservation,” do we need to think about other factors that could impact the lung throughout cold ischemia? Looking beyond temperature alone may reveal environmental variables that shape how the organ is actually preserved, not just how preservation is described.
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EXPANDING THE SCOPE

Routine Doesn’t Equal Reliable

The unique physiology of donor lungs makes them highly sensitive to pressure changes, where even small deviations can lead to over- or under-inflation. Yet current guidance on inflation pressure during packaging varies widely, making consistent practice difficult to achieve. These inconsistencies are amplified during air travel in pressurized cabins, now a routine part of donor lung transport.
 
Together, these realities show that discussions of “optimal” preservation cannot focus on temperature alone. True optimization requires managing both temperature and pressure to protect donor lungs throughout storage and transport.

TURNING UP THE PRESSURE

INCONSISTENT GUIDANCE

The final airway pressure in packaged donor lungs is dependant on multiple imprecise clinical procedures, with wide variability reported in practice and literature:

    •  Procurement guidelines have recommended holding lungs at a static inflation pressure of 12-15 cm H2O to avoid over- or under-distension.2

    • Other surgical protocols have cited that lungs should be inflated to pressures between 15-20 cm H2O before stapling the trachea.3

    • In practice, inflation is sometimes performed using total lung capacity as guidance with the trachea being clamped while the lungs are in a partially inflated state as a means of compensating for future pressure change due to air travel.4,5 

    • In addition, modern air transport imposes cabin pressure variations where lungs inflated to full capacity risk barotrauma during flights, highlighted more in depth below.  

THESE UNCERTAINTIES HAVE LED TO PRECAUTIONARY MEASURES:

These adjustments to lung inflation, intended to reduce the risk of overinflation and barotrauma during air travel, compound the already imprecise methods of lung packaging and preservation. As a result, donor lungs are often inflated to pressures below the recommended levels. 

CLINICAL CONTEXT

CASE EXAMPLE

In a clinical case example, airway pressure in donor lungs was recorded at a starting pressure of 9 cm H2O, below the guideline’s minimum threshold and potentially at a higher risk for atelectasis due to pressure changes during preservation. This highlights not only the challenge of achieving and maintaining the recommended inflation state, but also the variability and subjectivity employed while packaging donor lungs.6

pressure logs-1

Donor lungs were placed into the BAROguard System  at 9.3 cm H2O. Within 1 minute, the system adjusted the pressure of the lungs to be in the recommended range of 12-15 cm H2O.

FACTORING IN FLIGHTS

ACHIEVING NEW HEIGHTS

Beyond the variation in airway pressures due to imprecise clinical procedures and ongoing metabolism, these effects are magnified by pressure changes due to air travel.
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The US Federal Aviation Regulations 914 CFR 25.841 require that under normal operating conditions, cabin pressure altitude cannot exceed 8,000 ft at the aircraft’s maximum operating altitude. Going beyond this cabin pressure introduces structural stress on the airframe due to the pressure differential between the inside and outside of the fuselage.7
 

For this reason, both commercial and private aircraft cabins are not pressurized to sea level conditions.

Instead, cabins are pressurized to a lower atmospheric pressure, characteristic of higher elevation. Private aircrafts offer cabin pressurization roughly equivalent to altitudes between 3,000 and 5,000 ft, while direct measurements aboard Boeing 747-400 flights showed average cabin pressure of 863 cm H2O, corresponding to an altitude of 5,000-8,000 ft.8,10

ambient pressure

PRESSURE TRANSPARENCY

BAROMETRIC PRESSURE DATA COLLECTION

 

Ambient pressure data from nearly 100 clinical lung transplant cases has been collected using a mobile device’s onboard barometric sensor and the Paragonix digital application.

Donor lungs experienced an average ambient pressure decrease of 198 cm H2O as a result of increasing altitudes during air transport. Ambient pressure remained reduced for an average duration of 4.7 hours before returning to near sea-level conditions, accounting for different flight lengths. The average minimum ambient pressure experienced by lungs during transport was 838 cm H2O.

Across all cases, the lowest recorded ambient pressure was 767 cm H2O, consistent with the minimum cabin pressurization required for commercial aircraft (8,000 ft). The highest recorded ambient pressure was 1052 cm H2O.

Despite these fluctuations in ambient pressure,

BAROguard controlled the internal airway pressure of all donor lungs
within consensus range to an average of 14 ± 0.47 cm H2O for the duration of preservation.

ALL ENVIRONMENTAL FACTORS ARE CRITICAL.

Donor lungs are exposed to a wide range of pressure environments during transport from donor to recipient. Although clear protocols exist for protective ventilation at both the donor and recipient stages, pressure control during preservation and transport is often overlooked, potentially unraveling the careful work done on either end of the process. As the field of lung preservation continues to advance, it is critical that discussions of ‘optimal’ preservation address not only temperature control but also pressure control because we can all agree that donor lungs should be cold and inflated.

THE RIGHT COMBINATION.

A look into how comprehensive oversight and control of the environment can change preservation.
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View References List
  1. De Perrot et al., Strategies to optimize the use of currently available lung donors. JHLT 2004.
  2. Copeland et al. Donor heart and lung procurement: A consensus statement. JHLT 2020.\
  3. Kukreja et al., The 2024 American Association for Thoracic Surgery expert consensus document: Current standards in donor lung procurement and preservation. JHLT 2025.
  4. Cantu et al., Evaluation and Management of the Potential Lung Donor. Clin Chest Med 2018.
  5. Krishnan et al., Procurement of lungs from brain-dead donors. Indian J Thorac Cardiovasc Surg 2021.
  6. Langer, AATS MCS Industry Symposium 2025, Data on file. Delivering Textbook Outcomes in Lung Transplantation. September 5, 2025.
  7. Greenwald et al., Cabin pressurization characteristics of USAF and commercial transport aircraft. Aeromed Rev., 1967.
  8. Falcon 10X Aircraft. (6 May, 2021). https://www.dassaultfalcon.com/news/falcon-10x-2/#:~:text=Healthy%20cabin%20features:%20Cabin%20pressurization,for%20an%20even%20temperature%20throughout.
  9. Private Jet Charter. Gulfstream G650. https://privatejetcharter.com/aircraft/gulfstream-g650/#:~:text=Welcome%20to%20Private%20Jet%20Charter,an%20abundance%20of%20natural%20light.
  10. Kelly et al., Directly measured cabin pressure conditions during Boeing 747-400 commercial aircraft flights. Respirology 2007.
  11. Federal Aviation Administration. (2004). Pressurized compartment loads: General Structures Harmonization Working Group (Report No. ARAC TAEIG L-350-04-112). U.S. Department of Transportation. https://www.faa.gov/media/31686
  12. Geertsema C, et al. Effect of commercial airline travel on oxygen saturation in athletes. Br J Sports Med. 2008 Nov;42(11):877-81.