1 Department of Medicine, University of Hong Kong, Queen Mary Hospital, 2 Department of Medicine and Geriatrics, United Christian Hospital and 3 Department of Cardiothoracic Surgery, The Grantham Hospital, Hong Kong SAR, Peoples' Republic of China
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Methods and results. Between July 1998 and March 2002, among 475 CAPD patients in two regional hospitals in Hong Kong, nine patients (three men, six women, mean age 53±12 years) developed acute hydrothorax due to pleuroperitoneal communication (R=8, L=1) within 5.8±4.2 months (median, 5.2 m; range, 2 days to 11.6 months) of commencing peritoneal dialysis. Analysis of simultaneously obtained peritoneal and pleural fluid in all subjects only showed concordance in protein content (consistently<4 g/l), while fluid glucose and lactate dehydrogenase levels were not comparable. The methylene blue test was negative (n=4). Radionuclide scan (n=6) and contrast CT peritoneography (CTP, n=3) detected pleuroperitoneal communication in half and one-third of the patients, respectively. All patients underwent pleurodesis achieved by talc insufflation into the pleural cavity under VATS guidance. All patients were successfully returned to peritoneal dialysis. After a mean follow-up of 18.8±12.5 months, hydrothorax recurred in one patient (at 7 months after pleurodesis), who was successfully treated by repeating the procedure.
Conclusions. Hydrothorax complicating CAPD is more commonly right-sided, and tends to occur within the first year of starting peritoneal dialysis. Isotope scan and CTP are insensitive in diagnosing pleuroperitoneal communication. A low pleural fluid protein content is the most consistent biochemical finding. VATS talc pleurodesis is a safe and reliable treatment of choice that allows sustained continuation of CAPD with low recurrence rate.
Keywords: CAPD; hydrothorax; pleurodesis; talc poudrage
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
![]() |
Subjects and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
Contrast CT peritoneography
Iopamiro (150 ml) was diluted into 2 l of peritoneal dialysate solution, and the diluted contrast medium was then instilled into the peritoneal cavity through the Tenckhoff catheter. After dwelling for 2 h, 10 mm computed tomographic axial sections were taken from thorax to abdomen and pelvis. Delayed films were taken at 24 h.
Peritoneopleural scintigraphy
The patient performed CAPD bag exchanges as usual. The radio-isotope, Tc99m tin-colloid, 15 mCi, was injected under aseptic techniques into the peritoneal cavity via the Tenckhoff catheter. Dynamic anterior and posterior images were taken for 30 min. Delayed images were obtained at 3, 4, 6 and 24 h.
Direct visualization by methylene blue injection
Twenty millilitres of methylene blue was injected into a bag of dialysis solution to cause a conspicuous bluish discolouration. Diagnostic pleurocentesis was performed using fine needles. Pleural fluid was examined for the presence of similar discoloration.
Temporary haemodialysis
After a tentative diagnosis of pleuroperitoneal communication was established, CAPD was ceased and the subject was put on temporary haemodialysis via a dual-lumen internal jugular venous catheter. In all subjects, the initial pleural effusion completely subsided on chest radiograph taken 1 week after the commencement of haemodialysis. This, coupled with the other pertaining clinical information, is highly suggestive of a diagnosis of pleuroperitoneal communication. The subject was then ready for pleurodesis surgery.
Video-assisted thoracoscopic talc pleurodesis
All patients gave informed consent to undergo this procedure at a major cardiothoracic surgical centre at the Grantham Hospital. The patient was under general anaesthesia, and ventilated through a dual-lumen endotracheal tube, with the ipsilateral lung deflated. The patient was put in the decubitus position, with the side of operation (usually right) up. Three working ports were created. The first was made at the 8th intercostal space along the mid-axillary line for the introduction of the thoracoscope (Stryker 10 mm, zero degree endoscope). The other two were created at the 5th intercostal space along the anterior and posterior axillary lines. After inspection for any communication between the pleural and peritoneal cavities, and for any lung and pleural pathology, 10 g of talc powder was insufflated via a manually operated pump to ensure even distribution onto the lung surface. At the end of the procedure, two chest drains were introduced via the port sites, one toward the antero-apical region to drain air, and the other toward the postero-basal aspect to drain fluid.
Postoperative care
The apical drain would be removed on day 1 when the lung became fully expanded, and the basal drain would be removed when the drain output fell below 20 ml/day (which typically took 34 days). At this point, the patient can be discharged from hospital. For the first 3 weeks after talc pleurodesis, the patient would receive intermittent haemodialysis to allow adequate fibrosis. Peritoneal dialysis was then reinstated.
Statistical analysis
All data were expressed as mean±standard deviation. Intergroup differences for continuous variables were assessed by one-way analysis of variance. Statistical analysis was performed using SPSS statistical software (Statistical Package for the Social Sciences, Inc., Chicago, IL). Significance was defined as P<0.05.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
All subjects underwent VATS talc pleurodesis as described in the Subjects and Methods. The mean length of hospital stay was 4.5±1.9 days. One patient developed postoperative fever on day 1, which settled with paracetamol. Five patients experienced local wound pain at the sites of chest drain insertion, which improved with simple analgesic. There were no adverse respiratory symptoms or other adverse effect from talc infusion. After a brief period of haemodialysis postoperatively, all subjects were successfully returned to peritoneal dialysis. Chest radiograph showed complete resolution of the initial effusion in all patients. After a mean follow-up of 18.8±12.5 months, hydrothorax recurred in one subject (Patient 1) at 7.5 months after initial talc pleurodesis. This patient underwent the same procedure and resumed CAPD uneventfully. After 24 months of further follow-up, she is currently well on CAPD without recurrence. One patient died of intracranial haemorrhage 8 months after pleurodesis, and was well maintained on CAPD at the point of the cerebrovascular accident. One patient developed severe fungal peritonitis that necessitated removal of the Tenckhoff catheter 9 months after pleurodesis, and was converted to maintenance haemodialysis thereafter. All the other patients are currently well on CAPD. There was no significant change in peritoneal dialysis adequacy and ultrafiltration property in terms of Kt/V for urea and dialysate:plasma creatinine ratio at 4 h, respectively, before the onset of hydrothorax and after treatment by talc pleurodesis (data not shown). In addition, there was no clinically significant compromise in respiratory functional status consequent to the procedure.
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The methylene blue test was negative in all the subjects tested. This is probably due to the pressure effect of the hydrothorax, impeding the migration of the blue dye across the diaphragm. Isotopic scanning and contrast CT peritoneography were only positive in half and a third of the patients, respectively. Thus, these imaging techniques, while being sophisticated and expensive, are not sensitive or indispensable in detecting pleuroperitoneal communication. A recent case report from Ortiz and coworkers [7] showed that the yield of scintigraphy in a child with hydrothorax could be improved if the scanning was performed immediately after complete drainage of the hydrothorax, presumably due to relief of the high intrapleural pressure that impeded tracer migration.
The pathogenesis of hydrothorax in CAPD remains unclear. Leakage via diaphragmatic lymphatics, thoracic duct or through congenital or acquired defects or blebs with a one-way valve mechanism in the diaphragm have all been implicated [812]. The fact that anatomic defects are more commonly situated in the right hemi-diaphragm may account for the preponderance of right-sided hydrothorax in most series, including ours. Regardless of the underlying abnormality, the physiologic negative intrapleural pressure and the positive intraperitoneal pressure in CAPD act in concert to promote the transfer of dialysate from the abdominal to the pleural cavity, if a physiologic weak point exists. The clinical consequence of hemi-hydrothorax has once been considered an indication for permanent cessation of CAPD and transfer to haemodialysis [13,14]. Various manoeuvres of pleurodesis have been reported in the treatment of this condition, including mechanical rub pleurodesis [5,15], and chemical pleurodesis using tetracycline, fibrin glue, steroid, nocardia rubra cell wall skeleton, OK-432 (haemolytic streptococcal derivatives) and autologous blood [1,13,16,17]. Whatever the treatment used, the desired pleural adhesion was not always firmly formed, resulting in frequent recurrence of hydrothorax [1,3,1820]. Thoracoscopy-guided identification and direct obliteration of pleuroperitoneal communication [9,12] has been reported as another mode of treatment. However, most diaphragmatic defects are indeed microscopic and difficult to localize, even at autopsy [18,21].
To date, there is no consensus concerning the most effective therapeutic approach to CAPD-related hydrothorax. We chose talc poudrage for three reasons. First, talc is the most effective sclerosant agent to date and is extensively used to treat malignant pleural effusions, with reported success rates of 8793% [22,23]. Here, we showed that after a follow-up of 18.8 months, 89% of patients did not develop recurrence while being resumed on CAPD. Importantly, there was no compromise in chest outcome in terms of pulmonary function or radiologic appearance. Secondly, mechanical rub pleurodesis may be associated with more bleeding complications, and is undesirable in the uraemic state. Thirdly, we do not favour direct repair or obliteration of diaphragmatic flaws not only because they are difficult to localize intraoperatively [18,21], but also because the repair of such lesions does not prevent recurrence or the subsequent appearance of new defects. To our knowledge, there has been no report in the literature that systematically examined the outcome of VATS talc pleurodesis in the treatment of CAPD-related hydrothorax. Here, we showed that this procedure is well tolerated and effective. All patients were returned to CAPD successfully, except for one recurrence at 7.5 months that was also successfully treated by repeating the procedure.
In conclusion, hydrothorax-complicating CAPD developed in 1.9% of patients in our cohort. Eighty-nine per cent are right-sided. Assay of simultaneous peritoneal and pleural aspirate protein content is the simplest and cheapest way to suggest this clinical condition. This complication of CAPD does not mandate permanent cessation of peritoneal dialysis and conversion to maintenance haemodialysis. We recommend VATS talc pleurodesis as the therapy of first choice for pleuroperitoneal communication because of its safety, reliability and low recurrence rate.
Conflict of interest statement. None declared.
![]() |
Acknowledgments |
---|
![]() |
Notes |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|