Tidal fractional exhaled nitric oxide (FE(NO)) changes were investigated in healthy, unsedated infants with or without prenatal tobacco exposure. Tidal flow (V), FE(NO), and CO(2) were measured in 20 healthy, unsedated infants [age: 25-58 days, length: 56.5 +/- 2.5 (SE) cm]. NO output (VNO) was calculated (VNO = FE(NO) x V). Two approaches were used to investigate within-breath changes of FE(NO...

Bronchoaspiration results in local deterioration of lung function through direct damage and/or indirect systemic effects related to neurohumoral pathways. We distinguished these effects by selectively intubating the two main bronchi in pigs while a PEEP of 4 or 10cm H2O was maintained. Gastric juice was instilled only into the right lung. Lung mechanical and ventilation defects were assessed by...

A lumped two-compartment mathematical model of respiratory mechanics incorporating gas exchange and pulmonary circulation is utilized to analyze the effects of square, descending and ascending inspiratory flow waveforms during mechanical ventilation. The effects on alveolar volume variation, alveolar pressure, airway pressure, gas exchange rate, and expired gas species concentration are evaluat...

Mechanisms driving alteration of lung function in response to inhalation of a methacholine aerosol are incompletely understood. To explore to what extent large and small airways contribute to airflow limitation and airway closure in this context, volumetric capnography was performed before (n = 93) and after (n = 78) methacholine provocation in subjects with an intermediate clinical probability...

To examine the relationship of expired capnograms and respiratory system resistance (Rrs) in intubated critically ill patients, we consecutively studied 41 mechanically ventilated patients to (1) analyze the association between expired CO2 slope and auto-positive end-expiratory pressure (auto-PEEP), between Rrs and auto-PEEP, between Rrs and expired CO2 slope, and between Rrs and arterial minus...

BACKGROUND Pulmonary embolism (PE) produces ventilation/perfusion mismatch that may be manifested in various variables of the volume-based capnogram (VBC). We hypothesized that a neural network (NN) system could detect changes in VBC variables that reflect the presence of a PE. METHODS A commercial VBC system was used to record multiple respiratory variables from consecutive expiratory breath...

Intrabronchial capnography was applied in 11 lung cancer patients to investigate the effects of lobectomy on regional lung function. Spirometry and intrabronchial capnography were performed before surgery (PRE), and during the early (POST1,19 +/- 5 POD) and late (POST2, 184 +/- 98 POD) postoperative periods. End-tidal carbon dioxide concentration (EtCO2) and Smidt's velocity profile index (V-in...

drastically displaced. From our side, this has lead to an intelligent analytical procedure that we call “InCAP,” which groups waveforms into clusters.3 The cluster that most closely agrees with the normal capnogram is used for calculating PETCO2. This analysis system provides considerably better agreement between the data from cluster 1 and the PaCO2 value. The problematic nature of the convent...