The Validity of Sonographic Assessment of Intravascular Fluid Estimate (SAFE) Score in The Assessment of Volume State in Acute Kidney Injury Patients

Abstract

Background: Ultrasonography has gained popularity in the last two decades, with many critical care units standardizing point-of-care ultrasonography (POCUS) for ICU patient diagnosis and treatment.

Aim: To develop a reliable fluid status scoring system for critically ill cases, evaluate SAFE score's effectiveness, and assess organ evaluation and hemodynamic measures' utility.

Patients and methods: Prospective observational research has been performed from March 2021 to December 2022 at Kasr Al Ainy Hospital, Cairo University, Egypt, on 150 adult cases with acute kidney injury admitted to the Critical Care Department. The ICU physician selected patients based on their need to evaluate hemodynamic and volume status.

Results: No statistically significant relationship between standard hemodynamic measures (SBP, DBP, MAP, HR, and CVP) and either the SAFE score or LVOT VTI in assessing volume status. Among hypovolemic patients, 52.4% (11 out of 21) were volume responsive, while 47.6% (10 out of 21) were non-responsive. In contrast, 73.9% (82 out of 111) of euvolemic patients were non-volume responsive, with the remaining 26.1% being volume responsive. For hypervolemic patients, 83.3% (15 out of 18) were non-volume responsive. Kendall's tau-c statistic (0.166) indicated a weak correlation between the SAFE score and volume responsiveness by LVOT VTI after the PLR test, suggesting that while the SAFE score provides valuable insights, it may not strongly predict fluid responsiveness in all cases.

Conclusion: Fluid status assessment is crucial for ICU patient management, aiding resuscitation and de-resuscitation, but over-administration can increase morbidity and mortality.