Questions About PD
There are no trials guiding optimal treatment of hydrothorax in PD patients and treatment guidelines are opinion based. Cessation of CAPD is universally recommended to avoid high intra-abdominal pressure. Options at that point include what you have mentioned above: a period off dialysis if the patient has sufficient residual kidney function, conversion to a supine PD which is associated with a lower intra-abdominal pressure, or conversion to HD.
Which of these is the optimal approach is not clear, and likely depends on the individual patient. It seems reasonable to give a trial of dialysis cessation or supine dialysis if the patient can receive enough clearance. Failing this, HD would be a necessary bridge.
Pleuro-peritoneal fistulas can spontaneously resolve. A series by Chow et al. found that 53% of patients could resume long term CAPD after a period of cessation- generally 2 to 6 weeks is recommended (Chow, Seminars in Dialysis 2003, Szeto, Curr Opin Pulm Med 2004). If the leak does not heal spontaneously, other options include pleurodesis, video-assisted thoracotomy with either pleurodesis or repair of the defect or, rarely, thoracotomy.