Preoperative Pulmonary Preparation of Patients with COPD

We agree that a key procedure in the management of malignant pleural effusions is complete evacuation of pleural fluid from the pleural space so that the visceral pleural surface can come into contact with the parietal pleural surface at the time of instillation of the sclerosing agent. We also recommend that chest tube drainage be employed for this purpose.’ Tube drainage should be continued until the chest radiograph shows little or no pleural fluid and pleural space drainage is less than 150 ml per day. Further, complete pleural space drainage avoids the problem of dilution of the sclerosing agent which could impair its efficiency. Pleural symphysis will never be effective if the pleural surfaces are not in contact. An example of this would be in the case of a “trapped lung” from marked carcinomatous involvement of the visceral pleural surface. A clue that this situation exists is in the patient with a low pH-low glucose malignant effusion.’ We made an initial observation that the pH of the sclerosing agent could be an important determinant in the production of pleural symphysis.’ This was based on the results from clinical studies and measurement of the pH of different sclerosing agents. We have pursued this observation with experimental studies. We have instilled .01 N hydrochloric acid, which has a pH similar to that of tetracycline, into the rabbit pleural space and found that none of the animals developed pleural symphysis at 30 days. In addition, we have instilled 0.5 percent NaOH (pH = 13) into the rabbit pleural space and found no evidence of pleural symphysis at 30 days. In fact, the pleural space was entirely normal. In this animal model only tetracycline at 35 mg/kg produced pleural symphysis. Based on these experimental data, it appears that the pH of the sclerosing agent is not a critical factor in the production of pleural symphysis. Other properties of the sclerosing agent (in this case tetracycline) must be important in leading to fibrosis in the pleural space. Preliminary data suggest that enhancement of pleural fluid clotting and inhibition of pleura! fibrinolysis may be important in this regard.5’6