title: Impairment of respiratory muscle function in pulmonary hypertension.
abstract: 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.
authors.affiliation: Department of Pneumology, University Hospital Freiburg, D-79106 Freiburg Germany.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Kabitz
authors.forename: Anja
authors.initials: A
authors.lastname: Schwoerer
authors.forename: Hinrich-Cordt
authors.initials: HC
authors.lastname: Bremer
authors.forename: Florian
authors.initials: F
authors.lastname: Sonntag
authors.forename: Stephan
authors.initials: S
authors.lastname: Walterspacher
authors.forename: David
authors.initials: D
authors.lastname: Walker
authors.forename: Vanessa
authors.initials: V
authors.lastname: Schaefer
authors.forename: Nicola
authors.initials: N
authors.lastname: Ehlken
authors.forename: Gerd
authors.initials: G
authors.lastname: Staehler
authors.forename: Michael
authors.initials: M
authors.lastname: Halank
authors.forename: Hans
authors.initials: H
authors.lastname: Klose
authors.forename: Hossein A
authors.initials: HA
authors.lastname: Ghofrani
authors.forename: Marius M
authors.initials: MM
authors.lastname: Hoeper
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Gruenig
authors.forename: Wolfram
authors.initials: W
authors.lastname: Windisch
mesh_terms: 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
chemical_list: D015415:Biomarkers; D002245:Carbon Dioxide; D010100:Oxygen