- Pulmonary critical care
- Open Access
The prognostic value of the dead-space fraction and other physiological parameters in the weaning process of mechanical ventilation in patients with obstructive air flow
Egyptian Journal of Bronchology volume 9, pages 245–252 (2015)
Patients with obstructive air flow including chronic obstructive lung diseases and bronchial asthma use a substantial proportion of mechanical ventilation (MV) in the ICU, and their overall mortality with ventilator support can be significant. From the pathophysiological standpoint, they have increased airway resistance, pulmonary hyperinflation, and high pulmonary dead space, leading to an increased work of breathing. MV is an integral part of the treatment for acute respiratory failure.
Aim of the work
The present study aimed to demonstrate the prognostic value of ventilatory parameters including that of the dead-space fraction (DSF), end-tidal carbon dioxide (ETCO2), lung mechanics, and gas exchange during the application of MV.
Patients and methods
Forty consecutive patients admitted to the ICU with acute respiratory failure due to chronic obstructive lung diseases and acute severe asthma were enrolled in the study. Lung mechanics (compliance and airway resistance), DSF, ETCO2, and arterial blood gases were measured at the following times: on admission to the ICU, initially, and finally before extubation.
Successfully weaned and survivors represent 60% (n = 24) of all patients included in this study. They had a lower MV duration at a mean of 3.75 days ±1.8 SD. Logistic regression analysis revealed a significant association between the MV duration, pH more than 7.32, and dynamic compliance on the one hand and extubation failure on the other, but no significant association was found between the DSF and extubation failure, with odds ratio equal to 2.08 (95% confidence interval: 0.05–85.78, P = 0.7).
We concluded that DSF is not an influential predictor of extubation failure in patients with obstructive air flow, whereas dynamic compliance plays a strong prognostic role in the weaning process.
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Agmy, G.R., Mohammad, H.A. & Hassanin, A.A.M. The prognostic value of the dead-space fraction and other physiological parameters in the weaning process of mechanical ventilation in patients with obstructive air flow. Egypt J Bronchol 9, 245–252 (2015). https://doi.org/10.4103/1687-8426.165902
- bronchial asthma
- chronic obstructive lung diseases
- dead-space fraction
- lung mechanics
- mechanical ventilation