Chest
Volume 74, Issue 5, November 1978, Pages 540-542
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Clinical Investigations
Changes in Pulmonary Mechanics and Gas Exchange following Thoracocentesis

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In nine patients with large pleural effusions, we studied the changes in pulmonary mechanics and gas exchange that occurred in the first three hours following removal of 600 to 1,800 ml of fluid by thoracocentesis. There was a small but significant increase in the functional residual capacity and total lung capacity but no change in residual volume and vital capacity. Calculated pulmonary shunt fraction did not change. We could not relate the subjective improvements noted by patients after thoracocentesis to the changes in pulmonary volumes or blood gas levels.

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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

References (4)

  • OH Yoo et al.

    The effects of pleural effusion on pulmonary function

    Am Rev Respir Dis

    (1964)
  • K Kokkola

    Pulmonary function in exudative pleurisy

    Ann Clin Res

    (1972)
There are more references available in the full text version of this article.

Cited by (0)

Manuscript received March 13; revision accepted May 3.

**

Dr. Brown was supported by the Canadian Thoracic Society and by the Ontario Lung Association Block Term Grant.

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