In a dialysis patient with pleural effusion, does removal of fluid via dialysis stimulate coughing?

Cough During Pleural Effusion Drainage in Dialysis Patients

Yes, removal of pleural fluid via thoracentesis (not dialysis itself) can stimulate coughing in dialysis patients, and this cough is a critical warning sign that drainage must stop immediately to prevent life-threatening re-expansion pulmonary edema. 1

Understanding the Mechanism

Cough during fluid removal indicates excessive negative pleural pressure and impending re-expansion pulmonary edema, requiring immediate cessation of drainage regardless of the volume removed. 1 The mechanism involves:

• Rapid lung re-expansion creates mechanical stress on pulmonary vasculature, triggering cough reflexes as pleural pressure drops precipitously below -20 cm H₂O 1
• Vascular stretching and reperfusion injury during re-expansion stimulates irritant receptors in the airways, manifesting as persistent cough 1
• The development of cough signals that safe drainage limits have been exceeded, even if the absolute volume drained seems modest 1

Critical Clarification: Dialysis vs. Thoracentesis

The question conflates two separate processes. Dialysis (hemodialysis or peritoneal dialysis) removes fluid from the bloodstream or peritoneal cavity, not directly from the pleural space. 2, 3, 4 Pleural effusion requires thoracentesis or chest tube drainage to remove fluid from the pleural space. 5, 1

Safe Drainage Protocol to Prevent Cough

Drain no more than 1-1.5 liters at one time, or slow drainage to approximately 500 ml/hour if continuing beyond this threshold. 1 Specific parameters include:

• Continue drainage only if pleural pressure remains above -20 cm H₂O 1
• Stop immediately if end-expiratory pleural pressure falls below -20 cm H₂O, regardless of volume removed 1
• In patients without contralateral mediastinal shift, remove only small volumes as they have increased likelihood of precipitous pleural pressure falls 5, 1
• When contralateral mediastinal shift is present on chest radiograph and the patient tolerates thoracentesis without chest tightness, cough, or dyspnea, removal of several liters may be safe 5

Special Considerations in Dialysis Patients

Dialysis patients present unique diagnostic challenges:

• Peritoneal dialysis patients have 3-fold higher risk of chronic cough (22% vs 7% in hemodialysis) primarily due to gastroesophageal reflux from increased intraperitoneal pressure 1, 6
• Multiple pre-existing causes of chronic cough complicate assessment, including fluid overload, ACE inhibitors, and GERD 1, 6
• Distinguish between pre-existing chronic cough from dialysis-related causes and new-onset cough during drainage—the latter is a procedural complication requiring immediate cessation 1
• Pleuroperitoneal leak is a rare but important cause of pleural effusion specifically in peritoneal dialysis patients, presenting with high glucose concentration in pleural fluid 2, 4, 7

Critical Pitfalls to Avoid

Do not continue drainage to reach a volume target if cough develops—symptom development mandates immediate cessation regardless of volume drained. 1 Additional warnings:

• Do not drain rapidly without monitoring, as re-expansion pulmonary edema can occur from rapid removal even if absolute volume is modest 5, 1
• Do not ignore the warning signs (cough, chest pain, dyspnea) as these indicate dangerous negative pleural pressures that can lead to life-threatening re-expansion pulmonary edema 5, 1
• Do not apply excessive suction; if suction is needed, use high-volume, low-pressure systems with gradual increment to maximum -20 cm H₂O 1
• Do not assume all cough in dialysis patients is benign; evaluate for pulmonary edema from fluid overload, which can be life-threatening and requires optimization of dialysis ultrafiltration rather than thoracentesis 1, 6

When Cough Develops During Drainage

Stop drainage immediately. 1 The presence of cough during thoracentesis indicates:

• Pleural pressure has likely dropped below safe thresholds 1
• Risk of re-expansion pulmonary edema is imminent 5, 1
• Further drainage will not relieve dyspnea and may cause harm 5

If dyspnea is not relieved by thoracentesis, investigate other causes such as lymphangitic carcinomatosis, atelectasis, thromboembolism, or tumor embolism rather than continuing aggressive drainage. 5