The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
-
Randomized Controlled Trial Clinical Trial
Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise.
Supplemental oxygen has acute beneficial effects on exercise performance in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate whether oxygen-supplemented training enhances the effects of training while breathing room air in patients with severe COPD. A randomized controlled trial was performed in 24 patients with severe COPD who developed hypoxaemia during incremental cycle exercise (arterial oxygen saturation (Sa,O2) <90% at peak exercise). ⋯ Differences between groups were not significant. Pulmonary rehabilitation improved exercise performance and quality of life in both groups. Supplementation of oxygen during the training did not add to the effects of training on room air.
-
The characteristics and outcome of acute respiratory distress syndrome (ARDS) may have changed with time. Some studies have reported that mortality is more commonly related to the development of sepsis/multiple organ failure (MOF), and others that it is related to the severity of acute respiratory failure (ARF). The present study evaluates the relative importance of the two phenomena in a large series of patients. ⋯ In addition, mortality was higher in septic than in nonseptic patients, and lower in trauma and surgical than in medical patients. We conclude that sepsis/multiple organ failure is still the most common cause of death in acute respiratory distress syndrome. Improvements in outcome of acute respiratory distress syndrome may depend more on treatment of sepsis and multiple organ failure than on oxygenation measures.
-
The aim of this study was to test the hypothesis that differences in oxygen tension (PO2) and carbon dioxide tension (PCO2) values from measurements performed on different blood gas analysers in different laboratories are clinically insignificant. Samples of fresh whole human tonometered blood (PO2 8.1 kPa (60.8 mmHg); PCO2 5.3 kPa (39.9 mmHg)) were placed in airtight glass syringes and transported in ice-water slush. Blood gas analysis was performed within 3.5 h by 17 analysers (10 different models) in 10 hospitals on one day. ⋯ The standard deviations of a random measurement on a random analyser were 0.19 and 0.14 kPa (1.46 and 1.02 mmHg) for PO2 and PCO2, respectively. We conclude that the variability in measurement of blood gas values among different blood gas analysers, although negligible, depends much more on inter- than intra-instrument variation, both for oxygen tension and carbon dioxide tension. Technical improvements and adequate quality control programmes, including tonometry, may explain why the variability in blood gas values depends mainly on errors in the pre-analytical phase.
-
Several indices of ventilatory heterogeneity can be identified from the expiratory CO2 partial pressure or CO2 elimination versus volume curves. The aims of this study were: 1) to analyse several computerizable indices of volumetric capnography in order to detect ventilatory disturbances; and 2) to establish the relationship between those indices and respiratory system mechanics in subjects with normal lungs and in patients with acute respiratory distress syndrome (ARDS), both receiving mechanical ventilation. We studied six normal subjects and five patients with early ARDS mechanically ventilated at three levels of tidal volume (VT). ⋯ Changes in VT significantly altered capnographic indices in normal subjects, but failed to change ventilatory mechanics and VAE/VT in ARDS patients. After adjusting for breathing pattern, VAE/VT exhibited the best correlation with the mechanical parameters. In conclusion, volumetric capnography, and, specifically, the ratio of alveolar ejection volume to tidal volume allows evaluation and monitoring of ventilatory disturbances in patients with adult respiratory distress syndrome.
-
In subjects with normal lung mechanics, inspiratory muscle strength can be reliably and easily assessed by the sniff nasal inspiratory pressure (SNIP), which is the pressure measured in an occluded nostril during a maximal sniff performed through the contralateral nostril. The aim of this study was to assess the validity of the SNIP in patients with chronic obstructive pulmonary disease (COPD), where pressure transmission from alveoli to upper airways is likely to be dampened. Twenty eight patients with COPD were studied (mean forced expiratory volume in one second (FEV1) = 36% of predicted). ⋯ A false diagnosis of weakness was made in eight patients when MIP was considered alone, in four when SNIP was considered alone, and in only three patients when MIP and SNIP were combined. We conclude that both the sniff nasal inspiratory pressure and the maximal inspiratory pressure moderately underestimate sniff oesophageal pressure in chronic obstructive pulmonary disease. Although suboptimal in this condition, the sniff nasal inspiratory pressure appears useful to complement the maximal inspiratory pressure for assessing inspiratory muscle strength in patients with chronic obstructive pulmonary disease.