Background: Central venous oxygen saturation (ScvO₂) is correlated with cardiac output. In most patients, ScvO₂ declines during hemodialysis (HD) due to factors such as reduced preload, myocardial stunning, and intermittent arrhythmias. Previous research has shown that low ScvO₂ is associated with higher mortality in chronic HD patients. In this research, we tested the hypothesis that ScvO₂ variability is associated with all-cause mortality. Methods: We conducted a retrospective study in 232 chronic HD patients with central venous catheter as vascular access. ScvO₂ was recorded 1× per minute during dialysis using the Crit-Line monitor. A 6-month baseline comprising at least 10 dialysis treatments with ScvO₂ recordings preceded a follow-up period of up to 3 years. The coefficient of variation (CV) of ScvO₂ (100 times the ratio of the standard deviation and mean of ScvO₂) served as a measure of ScvO₂ stability during baseline. Patients were stratified by median population CV of ScvO₂ during baseline, and survival during follow-up was compared between the 2 groups by Kaplan Meier and multivariate Cox analysis. The association between CV of ScvO₂ and all-cause mortality during follow-up was further assessed by Cox analysis with a spline term for CV of ScvO₂. Results: The mean CV ± standard deviation of ScvO₂ in our population was 6.1 ± 2.7% and the median was 5.3%. Univariate Kaplan-Meier analysis (p = 0.043) and multivariate Cox analysis (hazard ratio [HR] 1.16; p = 0.0005) indicated that a CV of ScvO₂ > 5.3% was significantly associated with increased mortality. In Cox analysis with spline term, a CV of ScvO₂ >  11% was associated with a significantly increased HR for all-cause mortality. Conclusion: High ScvO₂ variability during dialysis is associated with increased all-cause mortality.

BackgroundIn hemodialysis patients, a third vaccination is frequently administered to augment protection against coronavirus disease 2019 (COVID-19). However, the newly emerged B.1.1.159 (Omicron) variant may evade vaccinal protection more easily than previous strains. It is of clinical interest to better understand the neutralizing activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants after booster vaccine or COVID-19 infection in these mostly immunocompromised patients.MethodsHemodialysis patients from four dialysis centers were recruited between June 2021 and February 2022. Each patient provided a median of six serum samples. SARS-CoV-2 neutralizing antibodies (nAbs) against wild type (WT) or Omicron were measured using the GenScript SARS-CoV-2 Surrogate Virus Neutralization Test Kit.ResultsForty-two patients had three doses of mRNA1273. Compared to levels prior to the third dose, nAb-WT increased 18-fold (peak at day 23) and nAb-Omicron increased 23-fold (peak at day 24) after the third dose. Peak nAb-WT exceeded peak nAb-Omicron 27-fold. Twenty-one patients had COVID-19 between December 24, 2021, and February 2, 2022. Following COVID-19, nAb-WT and nAb-Omicron increased 12- and 40-fold, respectively. While levels of vaccinal and post-COVID nAb-WT were comparable, post-COVID nAb-Omicron levels were 3.2 higher than the respective peak vaccinal nAb-Omicron. Four immunocompromised patients having reasons other than end-stage kidney disease have very low to no nAb after the third dose or COVID-19.ConclusionsOur results suggest that most hemodialysis patients have a strong humoral response to the third dose of vaccination and an even stronger post-COVID-19 humoral response. Nevertheless, nAb levels clearly decay over time. These findings may inform ongoing discussions regarding a fourth vaccination in hemodialysis patients.

Introduction: Inadequate fluid status remains a key driver of cardiovascular morbidity and mortality in chronic hemodialysis (HD) patients. Quantification of fluid overload (FO) using bioimpedance spectroscopy (BIS) has become standard in many countries. To date, no BIS device has been approved in the United States for fluid status assessment in kidney patients. Therefore, no previous quantification of fluid status in US kidney patients using BIS has been reported. Our aim was to conduct a cross-sectional BIS-based assessment of fluid status in an urban US HD population. Methods:We determined fluid status in chronic HD patients using whole body BIS (Body Composition Monitor, BCM). The BCM reports FO in liters; negative FO denotes fluid depletion. Measurements were performed before dialysis. Post-HD FO was estimated by subtracting the intradialytic weight loss from the pre-HD FO.Findings: We studied 170 urban HD patients (age 61 AE 14 years, 60% male). Pre-and post-HD FO (mean AE SD), were 2.2 AE 2.4 and À0.2 AE 2.7 L, respectively. Pre-HD, 43% of patients were fluid overloaded, 53% normally hydrated, and 4% fluid depleted. Post-HD, 12% were fluid overloaded, 55% normohydrated and 32% fluid depleted. Only 48% of fluid overloaded patients were hypertensive, while 38% were normotensive and 14% hypotensive. Fluid status did not differ significantly between African Americans (N = 90) and Caucasians (N = 61). Discussion: While about half of the patients had normal fluid status pre-HD, a considerable proportion of patients was either fluid overloaded or depleted, indicating the need for tools to objectively quantify fluid status.

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