Complications
Large pleural fluid collections can cause compressive atelectasis of surrounding lung.
Drainage of the pleural fluid will allow the lung to re-expand. However, re-expansion pulmonary edema is a possibility when large pleural fluid collections are drained quickly. For this reason it is advisable to drain a maximum of 1.5 L of fluid in any single sitting. If the patient becomes uncomfortable prior to 1.5 L, then the procedure should be terminated.
One meta-analysis suggests that pneumothorax occurs in approximately 6% of patients following either diagnostic or therapeutic thoracentesis, with a chest drain required in 2% of procedures.[3]
If the pneumothoraces are symptomatic, they should first be treated with aspiration. If the aspiration is unsuccessful, then a small-bore chest tube should be inserted.
Ultrasound guidance should be used to facilitate localization of the pleural fluid;[41] it has been shown to reduce the chance of iatrogenic pneumothoraces and organ puncture following thoracentesis.[26][117] However, benefit is lost once an effusion is marked and the patient moved, presumably due to differences in patient position,[118] and for this reason real-time ultrasound guidance is recommended.
Small pneumothoraces should be monitored with serial chest x-rays. Large pneumothoraces require insertion of a chest tube.
How to insert an intercostal (chest) drain using the Seldinger technique. Video demonstrates: how to identify a safe site for insertion; use of an introducer needle, guidewire, dilators, and intercostal drain; how to confirm drain position; and postprocedure care.
A rare complication that occurs when a chronically collapsed lung rapidly re-expands after removal of a large volume of pleural fluid or air by thoracentesis, especially in the first hour after insertion of the needle. Measures to reduce the risk of this include controlling the rate at which the fluid is drained, checking vital signs (every 15 min for the first hour), and chest drain volume checks after the procedure.[75][76] It is advisable to drain no more than 1.5 L of fluid in the first hour.[76] If the patient becomes uncomfortable prior to 1.5 L, then the procedure should be terminated.
The pathophysiological mechanisms are poorly understood but it manifests itself immediately, or within a few hours, of thoracentesis as unilateral pulmonary edema with acute chest pain, dyspnea and hypoxia.
It is commonly managed conservatively but if hypoxia persists, there may be recourse to continuous positive airway pressure.
Six months after therapy is initiated, many patients with pleural tuberculosis have residual pleural thickening. This is usually asymptomatic and does not require therapy.
Occasionally, a benign asbestos effusion will develop progressive pleural thickening. It is unclear whether any therapy is effective in this situation.
A pseudochylothorax is characterized by high cholesterol levels and occurs ≥5 years after a pleural effusion has been present.
Therapeutic thoracentesis is indicated if the patient is symptomatic.
In inflammatory states such as empyema, fibrous bands can start to form in <24 hours. If infected pleural effusions are not drained or are inadequately treated, fibroblasts grow into the pleural space forming a fibrous peel around the lung, preventing the lung from expanding. Active tumor encasement of the pleura can also cause this to occur.
In the case of trapped lung, decortication (the surgical removal of all fibrous tissue from the pleura) may be needed to allow the lung to re-expand. This procedure can be performed in the acute stages to control pleural sepsis, but if there is no ongoing infection and only residual thickened pleura with restrictive lung function, patients can be observed for 6 months. By this time, the pleural thickening usually improves or resolves.[119] If this does not occur, then decortication may be indicated.
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