Cystatin C and Kidney Function Recovery in Patients Requiring Continuous Kidney Replacement Therapy for Acute Kidney Injury.

BACKGROUND: Plasma cystatin C is a reliable marker to estimate kidney function; however, it is unknown whether this remains true in patients receiving continuous kidney replacement therapy (CKRT). Herein, we tested the hypothesis that lower concentrations of plasma cystatin C during the first three days of CKRT would predict kidney function recovery. METHODS: We performed a retrospective observational study of 72 patients from a 126-patient, single-center CKRT study. We studied two a priori defined cohorts of patients without advanced CKD who had acute kidney injury requiring CKRT (AKI-CKRT): 1) with early kidney function recovery defined as liberation from KRT within seven days of CKRT initiation versus 2) with delayed kidney function recovery defined as receipt of KRT for >21 days or death while on KRT. Subsequent analysis included patients with advanced CKD and intermediate kidney function recovery (liberation between 8 and 21 days). Cystatin C was then measured on stored plasma, urine, and dialysis effluent collected prior to CKRT initiation and on days 1, 2, and 3 of CKRT. RESULTS: Plasma cystatin C was significantly lower in patients with early kidney function recovery in comparison to patients with delayed kidney function recovery on days 1 (1.79 vs. 2.39mg/L), 2 (1.91 vs. 2.38mg/L) and 3 (2.04 vs. 2.67mg/L) of CKRT. Sieving coefficient and CKRT clearance of cystatin C were similar for patients with early and delayed kidney function recovery. The lowest plasma cystatin C concentration on days 1-3 of CKRT predicted early kidney function recovery with an area under the receiver operating curve of 0.77 (P = 0.002), positive likelihood ratio of 5.60 for plasma cystatin C <1.30mg/L, and negative likelihood ratio of 0.17 for plasma cystatin C ≥1.88mg/L. CONCLUSION: Lower plasma cystatin C concentrations during the first three days of CKRT are associated with early kidney function recovery.

Change in End-Tidal Co2 After Mini-Fluid Challenge to Determine Fluid Responsiveness.

Distributive shock is a major cause of morbidity and mortality in the ICU. IV fluid resuscitation is a vital intervention to improve cardiac output and end-organ perfusion during the initial resuscitation and for those who remain fluid responsive. Noninvasive measures of fluid responsiveness are lacking. The aim of this study is to assess whether changes in end-tidal co2 after mini-fluid challenge, or 250 mL bolus, can predict fluid responsiveness in mechanically ventilated patients with distributive shock. DESIGN: Single-center prospective study. SETTING: Patients were enrolled from 2019 to 2021 from the medical ICU within a single academic hospital. PATIENTS: Thirty-eight patients with paired measurements of fluid responsiveness as determined by bioreactance who were admitted to the ICU with a diagnosis of distributive shock and on mechanical ventilation. INTERVENTIONS: Stroke volume index (SVI), cardiac index, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and ETco2 were measured before and after completion of a mini-fluid challenge. Test characteristics of change in ETco2 (ΔETco2) greater than or equal to 2 after mini-fluid challenge to determine fluid responsiveness were calculated with percentage change in SVI greater than or equal to 10% used as the reference standard. MEASUREMENTS AND MAIN RESULTS: The sensitivity and specificity of a ΔETco2 greater than or equal to 2 mm Hg as a predictor of a change in SVI greater than or equal to 10% following a mini-fluid challenge were 20.0% and 91.3%, respectively. The area under the receiver operating characteristic curve was 0.62. CONCLUSIONS: A ΔETco2 greater than or equal to 2 mm Hg after mini-fluid challenge has limited test performance for determining fluid responsiveness in intubated patients with distributive shock.

Transfusion with Cryoprecipitate for Very Low Fibrinogen Levels Does Not Affect Bleeding or Survival in Critically Ill Cirrhosis Patients.

BACKGROUND: Fibrinogen (FIB) levels less than 150 mg/dL have been associated with increased rates of bleeding and lower survival in critically ill cirrhosis patients. OBJECTIVE: We aimed to determine if treatment with cryoprecipitate (CRYO) for low FIB levels is associated with bleeding outcomes or survival. METHODS: A total of 237 cirrhosis patients admitted to an intensive care unit at a tertiary care liver transplant center with initial FIB levels less than 150 mg/dL were retrospectively assessed for CRYO transfusion, bleeding events, and survival outcomes. RESULTS: The mean MELD score was 27.2 (95% confidence interval [CI]: 26.0-28.3) and CLIF-C acute on chronic liver failure score was 53.4 (51.9-54.8). Ninety-nine (41.8%) were admitted for acute bleeding and the remainder were admitted for nonbleeding illnesses. FIB level on admission correlated strongly with disease severity. After adjusting for disease severity, FIB on admission was not an independent predictor of 30-day survival (hazard ratio [HR]: 0.99, 95% CI: 0.99-1.01, p = 0.68). CRYO transfusion increased FIB levels but had no independent effect on mortality or bleeding complications (HR: 1.10, 95% CI: 0.72-1.70, p = 0.65). CONCLUSION: In cirrhosis patients with critical illness, low FIB levels on presentation reflect severity of illness but are not independently associated with 30-day mortality. Treatment of low FIB with CRYO also does not affect survival or bleeding complications, suggesting FIB is an additional marker of severity of illness but is not itself a direct factor in the pathophysiology of bleeding in critically ill cirrhosis patients.