Clinical profile and prognostic significance of intradialytic hypoxemia in patients undergoing hemodialysis

Abstract

Intradialytic hypoxemia (IH) is a frequently observed but insufficiently characterized phenomenon in maintenance hemodialysis (HD). Its associations with clinical phenotype, nutritional-inflammatory markers, and short-term outcomes in routine HD practice remain inadequately defined. The present study aimed to characterize the clinical profile of patients with IH and determine its prognostic significance for hospitalization rates and one-year survival.

Methods. A prospective single-center study included 120 HD patients. IH was defined as mean SpO₂ <94%, SpO₂ <94% for ≥10% of the HD session, and/or PaO₂ <70 mmHg. Patients were stratified into IH (n=26) and non-IH groups (n=94). Arterial blood gases, SpO₂ trends, spirometry, biochemical parameters, hospitalization frequency, and survival were evaluated.

Results. Patients with IH demonstrated a lower PaO₂: 68.1±5.4 vs. 87.3±7.2 mmHg (p<0.0001); lower mean SpO₂: 92.1±1.8% vs. 96.4±1.2% (p<0.001); greater duration of desaturation (SpO₂ <94%): 62.6% vs. 5.1% of session time (p<0.0001); and lower serum albumin: 34.2±4.8 vs. 38.5±3.9 g/L (p<0.001). Concomitant intradialytic hypertension was more frequent in the IH group (34.6% vs. 11.8%, p=0.0078). Hospitalization frequency was markedly higher among patients with IH: 1.7–2.1 hospitalizations per patient per year, depending on the presence of intradialytic hypertension, compared with 1.2–1.6 in the non-IH group (U=2359.0; p=2.01×10⁻¹⁹). A trend toward reduced one-year survival was observed in the IH group: 81.62% vs. 91.49% (log-rank p=0.06).

Conclusions. IH in HD patients is associated with significant impairments in oxygenation, lower nutritional–inflammatory status, and substantially higher hospitalization rates, with a trend toward reduced survival. IH may represent a clinically relevant marker of elevated short-term risk. Routine SpO₂ monitoring may improve early identification of high-risk patients.