Chest
Clinical InvestigationsChanges in Pulmonary Mechanics and Gas Exchange following Thoracocentesis
Section snippets
Materials and Methods
Nine patients with large unilateral pleural effusions from differing causes were studied after informed consent was obtained. Their clinical data are summarized in Table 1. The pleural effusions were aspirated through an Abrams biopsy needle, and pleural biopsies were obtained. After thoracocentesis, the patients were free of pain, and none had pneumothorax as assessed with chest x-ray films taken shortly after the procedure. Diagnoses were established with the aid of cytologic studies of the
Pulmonary Mechanics
The individual and group means of pulmonary volumes before and after thoracocentesis are given in Table 2. The pulmonary volumes before thoracocentesis are in keeping with a restrictive pulmonary defect. Following the removal of pleural fluid, there were small but significant increases in FRC (P < 0.02) and TLC (P < 0.05) but not in RV or VC. The most striking observation was that the VC increased by more than 200 ml in only two of the nine patients. There was no relationship between the volume
Discussion
When fluid is aspirated from the thoracic cavity, the volume removed may be associated with one of the following changes in pulmonary volume and the size of the thoracic cavity at FRC. There may be an increase in pulmonary volume without any decrease in the size of the thoracic cavity. Under these circumstances the increase in pulmonary volume at FRC will be equal to the volume of fluid aspirated. Secondly, there may be a decrease in the size of the thoracic cavity without any change in
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Cited by (70)
Anatomy and Applied Physiology of the Pleural Space
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2021, Encyclopedia of Respiratory Medicine, Second EditionPerioperative Considerations for Chylothorax
2017, Journal of Cardiothoracic and Vascular AnesthesiaCitation Excerpt :Pleural effusions cause dyspnea and decreased arterial oxygenation.1 Thoracentesis can relieve dyspnea2 but has inconsistent effects on oxygen saturation.3–5 In the presence of a pleural effusion, intrapulmonary shunt induces decreased oxygen saturation.6,7
CT Volumetric Analysis of Pleural Effusions: A Comparison with Thoracentesis Volumes.
2015, Academic RadiologyDrainage of pleural effusion in mechanically ventilated patients: Time to measure chest wall compliance?
2014, Journal of Critical CareSymptom relief after large-volume thoracentesis in the absence of lung perfusion
2014, ChestCitation Excerpt :This patient's improvement in breathlessness cannot, therefore, be attributed to improved gas exchange and suggests that the primary physiologic basis for the relief in dyspnea is a change in respiratory system mechanics and/or work of breathing. The mechanism of relief after large-volume thoracentesis was first investigated by Brown et al,1 who described significant relief after thoracentesis despite a lack of improvement in lung volumes or gas exchange in patients with large pleural effusions. The authors concluded that this relief could be due to a placebo effect.
Manuscript received March 13; revision accepted May 3.
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Dr. Brown was supported by the Canadian Thoracic Society and by the Ontario Lung Association Block Term Grant.