Impairment of respiratory muscle function in pulmonary hypertension.
It has been suggested that impaired respiratory muscle function occurs in patients with PH (pulmonary hypertension); however, comprehensive investigations of respiratory muscle function, including the application of non-volitional tests, needed to verify impairment of respiratory muscle strength in patients with PH have not yet been performed. In the present study, respiratory muscle function was assessed in 31 patients with PH (20 females and 11 males; mean pulmonary artery pressure, 51+/-20 mmHg; median World Health Organization class 3.0+/-0.5; 25 patients with pulmonary arterial hypertension and six patients with chronic thromboembolic PH) and in 31 control subjects (20 females and 11 males) well-matched for gender, age and BMI (body mass index). A 6-min walking test was performed to determine exercise capacity. Volitionally assessed maximal inspiratory (7.5+/-2.1 compared with 6.2+/-2.8 kPa; P=0.04) and expiratory (13.3+/-4.2 compared with 9.9+/-3.4 kPa; P<0.001) mouth pressures, sniff nasal (8.3+/-1.9 compared with 6.6+/-2.2 kPa; P=0.002) and transdiaphragmatic (11.3+/-2.5 compared with 8.7+/-2.5 kPa; P<0.001) pressures, non-volitionally assessed twitch mouth (1.46+/-0.43 compared with 0.97+/-0.41 kPa; P<0.001) and transdiaphragmatic (2.08+/-0.55 compared with 1.47+/-0.72 kPa; P=0.001) pressures during bilateral anterior magnetic phrenic nerve stimulation were markedly lower in patients with PH compared with control subjects. Maximal inspiratory mouth (r=0.58, P<0.001) and sniff transdiaphragmatic (r=0.43, P=0.02) pressures were correlated with the 6-min walking distance in patients with PH. In conclusion, the present study provides strong evidence that respiratory muscle strength is reduced in patients with PH compared with well-matched control subjects. Furthermore, the 6-min walking distance is significantly linked to parameters assessing inspiratory muscle strength.
Kabitz
Hans-Joachim
HJ
Department of Pneumology, University Hospital Freiburg, D-79106 Freiburg Germany.
Schwoerer
Anja
A
Bremer
Hinrich-Cordt
HC
Sonntag
Florian
F
Walterspacher
Stephan
S
Walker
David
D
Schaefer
Vanessa
V
Ehlken
Nicola
N
Staehler
Gerd
G
Halank
Michael
M
Klose
Hans
H
Ghofrani
Hossein A
HA
Hoeper
Marius M
MM
Gruenig
Ekkehard
E
Windisch
Wolfram
W
D000328:Adult; D000368:Aged; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood / Q000503:physiopathology*; D001239:Inhalation; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000503:physiopathology; D012132:Respiratory Muscles / Q000503:physiopathology*; D014797:Vital Capacity
D015415:Biomarkers; D002245:Carbon Dioxide; D010100:Oxygen