title: Prognostic value of mouth occlusion pressure in patients with chronic ventilatory failure.
abstract: BACKGROUND
  Mouth occlusion pressure measurement is widely used for assessment of respiratory muscle function, particularly in patients with respiratory failure. However, its predictive value for long-term survival remains largely unexplored.
  
  
  METHODS
  In 464 patients with chronic hypercapnic respiratory failure (CHRF) due to various underlying disorders and receiving non-invasive ventilation (NIV), maximal inspiratory mouth pressure (PI(max)), mouth occlusion pressure at 100 ms during quiet breathing (P(0.1)) and the ratio P(0.1)/PI(max) were assessed prior to and after treatment including NIV. Baseline data and changes at follow-up were used to evaluate their predictive value for long-term survival.
  
  
  RESULTS
  Overall, median (quartiles) P(0.1) was 177.0 (109.2;287.0) %pred, PI(max) 35.0 (24.0;47.0) %pred, and P(0.1)/PI(max) 564.0 (275.7;1082.3) %pred. In multivariate analyses, P(0.1) was related to airflow obstruction, lung hyperinflation, haemoglobin (Hb) and leukocytes, and PI(max) to airflow obstruction and hyperinflation (p<0.05 each). All-cause mortality during follow-up (median 31.6 months) was 31.5%. Survival was associated with age, body-mass index (BMI), lung function, leukocytes, Hb, PI(max), P(0.1) and P(0.1)/PI(max) (p<0.01 each, univariate). Among these multivariate Cox regression identified age, BMI, FEV(1), leukocytes and P(0.1)/PI(max) as independent predictors (p<0.05 each). Furthermore, the decrease of P(0.1)/PI(max) at follow-up was associated with improved survival in patients with high baseline P(0.1)/PI(max) (>50th or 75th percentile; p<0.05).
  
  
  CONCLUSIONS
  In patients with CHRF and current NIV therapy, P(0.1)/PI(max) was an independent predictor of long-term survival, in addition to previously established risk factors. Moreover, a decrease in P(0.1)/PI(max) after treatment including NIV was associated with an improved survival in patients with high baseline P(0.1)/PI(max) values.
authors: Center for Pneumology, Donaustauf Hospital, Ludwigstrasse 68, D-93093, Donaustauf, Germany. stephan.budweiser@klinik.uni-regensburg.de
authors: Stephan
authors: S
authors: Budweiser
authors: Rudolf A
authors: RA
authors: Jörres
authors: Carl-Peter
authors: CP
authors: Criée
authors: Veronika
authors: V
authors: Langer
authors: Frank
authors: F
authors: Heinemann
authors: André P
authors: AP
authors: Hitzl
authors: Kathrin
authors: K
authors: Schmidbauer
authors: Wolfram
authors: W
authors: Windisch
authors: Michael
authors: M
authors: Pfeifer
mesh_terms: D000368:Aged; D001784:Blood Gas Analysis; D002908:Chronic Disease; D003627:Data Interpretation, Statistical; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology*; D007320:Inspiratory Capacity / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D012131:Respiratory Insufficiency / Q000175:diagnosis* / Q000401:mortality*; D012132:Respiratory Muscles / Q000502:physiology*; D012720:Severity of Illness Index