Importance of medical history in diagnosis of global respiratory failure in patients suffering from neuromuscular diseases and thoracic deformities

Patients suffering from neuromuscular diseases and thoracic deformities may develop global respiratory failure during their illness. We wanted to judg e clinical parameters and information from the patients' medical history to reliably, quickly and noninvasively diagnose a ventilatory failure. Theref ore we evaluated 105 situations with and without mechanical ventilation fro m 29 patients with indication for noninvasive nocturnal mask ventilation. 6 clinical parameters (e.g. heartrate, oxygen saturation, relative vital cap acity), 2 test results (pH and partial pressure of carbon dioxide (pCO(2))) and 6 parameters from the patients' medical history (e.g. nycturia, fronta l headache in the morning, breathlessness) were investigated. After statist ical evaluation we could show a relation between heart rate and pCO(2) (Spe arman's correlation: r = 0,331, p = 0,001, n = 105; one-tailed significance : r = 0,335, p = 0,038, n = 29). Significant differences between the groups of nycturia incidence indicate a tight relation between the incidence of n ycturia and the heigth of hypercapnia levels (ANOVA - analysis of variance: p = 0,001). Using logistic regression we could show that information regar ding medical history, especially nycturia, frontal headache and indrawings, gives important indications for global respiratory failure (sensitivity 97 ,62 -100%, specifity 57,14-76,19%). Pathogenesis needs to be elaborated fur ther.