Transcutaneous monitoring of blood gas tensions in patients on intermittent peritoneal dialysis.

Abstract

A relative contraindication to intermittent peritoneal dialysis (IPD) is chronic lung disease. To evaluate whether the instillation of 2 L of fluid into the peritoneal cavity affects respiratory function, five IPD patients were studied in the supine position during the first 4 h of a routine IPD session. Blood gas tensions were monitored transcutaneously throughout the study period. At the onset of dialysis, mean transcutaneous blood oxygen tension (PtcO2) was 70.6 +/- 9.1 mm Hg. It decreased to 55 +/- 9.9 mm Hg (22% change from basal values) during the instillation of dialysate. Upon drainage, PtcO2 returned to baseline. This sequence of events repeated itself on subsequent exchanges, although with decreasing decrements of PtcO2 with each consecutive exchange (decrease to 58.6 +/- 7.05, 61 +/- 6.5, 63.8 +/- 5.2 mm Hg corresponding to 16%, 12.7%, and 9.6%, respectively, during the second to fourth exchanges). Transcutaneous blood carbon dioxide tension, PtcCO2, showed a very mild increase during the study (33 +/- 7.1 to 38 +/- 6.0 mm Hg). In two patients, the same study protocol was performed during the last 4 h of an IPD session. In these two patients, there was only a 5% variation of PtcO2 from baseline values. These results suggest that an adaptive response to the hypoxemia induced by dialysate instillation rapidly occurs in IPD patients.