Impact of Primary Indications and Comorbidities for Pediatric High Altitude Simulation Studies

Abstract

Background:

During commercial flights, planes are pressured to higher altitudes with approximately 15.1% FIO₂ available for breathing. In the pediatric population there are many patients with lower respiratory reserves that could be affected by lower FIO₂. As COVID flight restrictions were lifted, our institution experienced an increase in ordered pediatric high altitude simulation test studies (pHAST). We aimed to determine if there were any primary indications or comorbidities for pHAST studies at our institution that RTs could help identify to support safe air travel for our pediatric patients and their families.

Methods:

An IRB-exempt, retrospective chart review was completed and included all patients who completed a pHAST study within the last 10 years at our institution (24 ordered, 14 completed; n = 14). pHASTs were performed by RTs under supervision of the pulmonologists and followed standard HAST protocol (15-16% FIO₂).

Results:

The most common primary indication for all ordered pHAST was chronic lung diseases of prematurity (CLDP) (45.8%) and the most common comorbidity was asthma (70.8%). Of all studies that had abnormal results, the most common indication was CLDP (50%). Seventy-five percent of patients with abnormal studies had asthma as a comorbidity.

Conclusions:

While the conclusions are limited by small sample size, there appears to be a correlation between those for whom the test is most frequently ordered and those with abnormal results, indicating appropriate patient selection. In the future, respiratory therapists could suggest those patients who plan to fly with certain indications and comorbidities may benefit from a pHAST study prior to travel. Further studies should be completed with larger sample size to validate these findings.

Characteristics	Total Cohort (n=24)	Completed (n=14)	Normal (n=10)	Abnormal (n=4)
	% (n)	% (n)	% (n)	% (n)
Primary Indication
CLD prematurity	45.8 (11)	35.7 (5)	30 (3)	50 (2)
Restrictive Lung Disease	37.5 (9)	50 (7)	50 (5)	50 (2)
Sickle Cell Disease	12.5 (3)	7.1 (1)	10 (1)	0
Obstructive Lung Disease	4.2 (1)	7.1 (1)	10 (1)	0
Comorbidities
Cardiac	29.2 (7)	28.6 (4)	30 (3)	25 (1)
Asthma	70.8 (17)	57.1 (8)	50 (5)	75 (3)
OSA	8.3 (2)	0	0	0
Neurodevelopmental	37.5 (9)	35.7 (5)	30 (3)	50 (2)