Respiratory care
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Selection of the PEEP associated with the best compliance of the respiratory system during decremental PEEP titration can be used for the treatment of patients suffering from ARDS. We describe changes in transpulmonary pressure (Ptp) and gas exchange during a decremental PEEP titration maneuver in subjects with pulmonary ARDS. ⋯ During decremental PEEP titration we sequentially observed high inspiratory Ptp that stressed lung tissue and increased VD/VT, and negative Ptp, indicating high risk of alveolar collapse, explaining worse oxygenation. PEEP selection based on Ptp and VD/VT in ARDS may help to avoid these situations.
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Airway occlusion pressure 0.1 s after the start of inspiratory flow (P0.1) is used as an index of respiratory motor output; however, the reliability of P0.1 in this capacity has not been sufficiently investigated. Therefore, the aim of our study was to examine the reliability of P0.1. ⋯ Although a single measurement of P0.1 was somewhat reliable, the 95% CIs indicated that it is necessary to determine the average value of 3 or more measurements. The minimum of 4 repeat measurements were required to obtain valid results, indicating that the current method of determining P0.1 by averaging the values from at least 4 repeated measurements is valid.
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Comparative Study
Evaluation of interpretation strategies and substantial bronchodilator response in pediatric patients with normal baseline spirometry.
Controversy exists regarding the best method to interpret pediatric spirometry. There is also controversy regarding the benefit of performing post-bronchodilator spirometry after normal baseline spirometry. This study compares the use of lower limit of normal (LLN) against percent of predicted (PP) in the interpretation of spirometry. We also investigate the occurrence of a substantial bronchodilator response for patients who received post-bronchodilator spirometry. ⋯ The use of LLN for interpretation is more likely to report a test as normal, when compared to the PP interpretation strategy. Although a substantial bronchodilator response is more likely to occur following abnormal baseline spirometry, 10-12% of subjects with normal baseline spirometry showed a substantial bronchodilator response. This suggests that normal baseline spirometry may miss reversible airway obstruction, which is a hallmark of asthma.
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Observational Study
The 6-minute walk test in chronic respiratory failure: does observed or predicted walk distance better reflect patient functional status?
Acquiring 6-min walk test (6MWT) data from patients undergoing noninvasive mechanical ventilation due to chronic hypercapnic respiratory failure is limited. We aimed to assess whether the actual 6-min walk distance (6MWD) or the percent predicted 6MWD is a better reflection of the respiratory function of patients using home noninvasive ventilation (NIV) due to chronic hypercapnic respiratory failure. ⋯ The percent-of-predicted 6MWD was better correlated with respiratory function than actual 6MWD for subjects using home NIV due to chronic hypercapnic respiratory failure with COPD, OHS, kyphoscoliosis, and parenchymal lung disease.
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Pulmonary hypertension is an independent risk factor for death in patients with COPD. Current prognostic models of COPD do not include sufficient indicators of right ventricular (RV) function to enable accurate assessment of changes in RV function over time. The aim of the present study was to test the hypothesis that it would be useful to include noninvasive markers of RV function in the routine assessment and prognostic models of early stage COPD with or without pulmonary hypertension. ⋯ It may be valuable to add assessment of RV function to the routine evaluation of physical status in patients with COPD.