CONTINUOUS, IN-LINE MONITORING OF OXYGEN-SATURATION IN HEMODIALYSIS

Intradialytic hypoxemia was studied via continuous, in-line monitoring of oxygen saturation (O-2 Sat) in 16 patients during six independent 3- to 4-hour dialysis sessions (three patient treatments were aborted). The results of 93 runs showed a mean decrease in O-2 Sat from pre- to post-dialysis of -1.4%. No significant change in O-2 Sat was observed during the occurrence of morbid events such as hypotension, cramping, or lightheadedness. Twenty-six percent (24/93) of the treatment sessions showed a 2-8% decrease in O-2 Sat during the first hour of dialysis. Fifty-six percent (9 of 16 patients) experienced at least one episode of hypoxemia (defined as O-2 Sat <90% during 51 of the 93 treatments. Two of the 16 patients exhibited intradialytic sleep apnea, and two others with chronic obstructive pulmonary disease (COPD) exhibited O-2 Sat levels between 77 and 89% during dialysis. Since the continuous, in-line O-2 Sat monitor is insensitive to poor skin perfusion, it is not affected by hypotension, multiple previous shunts, low body temperature, and other dialysis-related factors that cause errors in pulse oximeters. Continuous, in-line monitoring of O-2 Sat could prove to be useful in identifying the underlying mechanisms ofhypoxemia, and in diagnosing and treating sleep apnea, COPD, pulmonary edema, and other complications