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Difference in Steady‐state Chemoreflex Drive Between Groups With and Without a Patent Foramen Ovale
Author(s) -
Zehner Donna,
ScanagattaLong Mollie,
Goodman Randall,
Futral Eben,
Hawn Jerold,
Elliott Jonathan,
Laurie Steven,
Roach R.C.,
Day Trevor,
Lovering Andrew
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.04586
Subject(s) - effects of high altitude on humans , acclimatization , patent foramen ovale , altitude (triangle) , ventilation (architecture) , population , cardiology , anesthesia , zoology , medicine , biology , anatomy , mathematics , ecology , physics , geometry , meteorology , environmental health , migraine
Ventilatory acclimatization is a hallmark physiological response to high altitude. In ~30% of the population, a shunt located between the right and left atrium called patent foramen ovale (PFO) is present. People with a PFO have a reduced degree of ventilatory acclimatization which may contribute to their increased risk for high altitude illnesses. Recently, the development of a steady‐state chemoreflex drive (SS‐CD) index has provided a novel approach to assessing the overall ventilatory drive at altitude. Using data from a previous high‐altitude expedition (AltitudeOmics), the SS‐CD index (SS‐CD = Minute ventilation (V E ), / (arterial partial pressure of carbon dioxide (PaCO 2 ) / arterial oxygen saturation (SaO 2 )) was utilized to quantify differences in the degree of ventilatory acclimatization between groups with a PFO, (PFO+) and without a PFO, (PFO‐). We aimed to test two hypotheses: 1) PFO‐ subjects would have a higher SS‐CD than PFO+ subjects 2) PFO+ subjects would have no significant change in their SS‐CD from ALT1 to ALT16. Twenty‐one participants (n=11 PFO+, n=10 PFO‐) participated in a high‐altitude study during which they spent 16 days at 5260 meters in Bolivia. V E , PaCO 2 , and SaO 2 data were collected at sea level (SL), day 1 at 5260m (ALT1), and day 16 at 5260m (ALT16). V E was obtained using a pneumotach. PaCO 2 and SaO 2 were obtained from a radial artery catheter. A mixed‐model 2 way repeat measure ANOVA was performed for statistical analysis with Tukey's multiple comparisons test. There was a main effect of time on the SS‐CD (p<0.0001), but no significant difference between PFO+ and PFO‐ subjects (p=0.2). Within PFO+ and PFO‐ subject groups the SS‐CD significantly increased from SL to ALT16 (PFO+ : 33.5 ± 5.9 vs 80.9 ± 47.8, p=0.0006; PFO‐ : 37.7 ± 10.3 vs 103.1 ± 44.2, p<0.0001) and from ALT1 and ALT16 (PFO+ : 43.16 ± 9.2 vs 80.9 ± 47.8, p=0.0077; PFO‐ : 52.08 ± 14.3 vs 103.1 ± 44.2, p=0.0052). Using the SS‐CD to quantify chemoreceptor drive between groups, our findings suggest the overall chemoreflex drive from ALT1 to ALT16 in both groups reflects significant changes in ventilation. Additionally, PFO+ subjects exhibit no differences in their overall chemoreflex response to altitude from PFO‐ subjects, despite significant differences in a more classical index of drive (i.e., change in VE/change in SaO 2 ). Future research should aim to investigate this inconsistency in chemoreflex responses in PFO+ and PFO‐ subjects at altitude.