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Cardiorespiratory Dysfunction in Advanced Lung Disease versus Systemic Lupus
Author(s) -
Wooten Liana C,
Chin Lisa M.K.,
Collins John,
Chan Leighton,
Keyser Randall E.
Publication year - 2017
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.31.1_supplement.1016.1
Subject(s) - medicine , cardiorespiratory fitness , cardiology , heart rate , respiratory exchange ratio , anaerobic exercise , interstitial lung disease , vo2 max , pulmonary hypertension , respiratory system , treadmill , oxygen pulse , lung , blood pressure , physical therapy
The cardiorespiratory responses to a peak exercise challenge were compared among women manifesting three autoimmune mediated conditions, pulmonary hypertension (PH), interstitial lung disease (ILD) and systemic lupus erythematous (SLE), and sedentary but otherwise healthy controls. Methods 80 women (PH N=28, age=54.0 ± 10.3, BMI=31.8 ± 7.3; ILD N=9, age=55.8 ± 7.2, BMI=29.7 ± 4.6; SLE N=25, age=35.1 ± 9.0, BMI=27.6 ± 5.8; Control N=18, age=36.8 ± 7.3, BMI=39.3 ± 8.8) completed a treadmill cardiopulmonary exercise test (CPET) to volitional exhaustion. Heart rate was obtained by continuous EKG monitoring and pulmonary gas exchange information was obtained using a breath‐by‐breath cardiopulmonary exercise testing system. Peak exercise oxygen consumption (VO 2 ), heart rate (HR) and respiratory exchange ratio (RER) were recorded as an average of the last 8 consecutive breaths. Oxygen pulse (O 2 ‐pulse) was calculated and the V‐slope method was used to determine VO 2 observed at the anaerobic threshold (AT‐VO 2 ). Data were analyzed for statistical significance (p<0.05) using analysis of variance and Cohen's d ‐statistic for effect size. Results Peak RER was ≥ 1.10 in all groups except PH (RER = 1.00 ± 0.25). Peak VO 2 and AT‐VO 2 was significantly lower in the PH, ILD, and SLE groups compared to controls (p<0.01).Peak VO 2 (ml/kg/min) AT‐VO 2 (ml/kg/min) Peak HR (beats/min) O 2 ‐Pulse (ml/beat)PH 15.3 ± 5.4 10.3 ± 4.3 139 ± 17 9.2 ± 4.6 ILD 18.2 ± 5.9 11.7 ± 3.8 150 ± 19 9.6 ± 4.6 SLE 19.4 ± 4.8 12.5 ± 3.2 171 ± 18 8.3 ± 1.9 Control 28.8 ± 5.2 16.4 ± 2.2 180 ± 10 11.0 ± 2.3Peak VO 2 was lower in PH than in SLE (p=0.031), whereas AT‐VO 2 was similar among PH, ILD and SLE. No difference in peak HR was observed between SLE and controls or between PH and ILD, however peak HR was significantly higher in SLE than in ILD (p=0.009) and PH (p=0.001). While not statistically significant, the size of the group difference in O 2 ‐pulse was large (Cohen's d = 1.283). Discussion Previous studies have demonstrated similarity in peak cardiac output and stroke volume between healthy controls and patient subsets with autoimmune conditions such as PH, ILD and SLE. The decline in peak VO 2 and HR across the PH and ILD groups, compared to controls, in concomitance with the disappearance of this decline with respect to O 2 ‐pulse may suggest peripheral muscle fatigue as a factor limiting exercise tolerance in these groups. The large effect in SLE with respect to the decline in O 2 ‐pulse and similarity in peak HR with controls may provide further evidence for peripheral oxygen extraction impairment in women with SLE. Support or Funding Information Supported by NIH/NICHD/NCMRR HD39775; NIH IRP 1 Z01 CL060068‐02 CC