Extracorporeal circuit temperature gradient and hemodynamic instability during continuous renal replacement therapy:...

Area of Science:

• Nephrology
• Critical Care Medicine
• Cardiovascular Physiology

Background:

• Continuous renal replacement therapy (CRRT) can influence hemodynamic stability.
• Lowering extracorporeal circuit temperature (T°_CRRT) relative to core temperature (T°_CORE) may impact hemodynamic instability risk (HIRRT) by altering cardiac output (CO) and vasomotor tone.

Purpose of the Study:

• To identify mediators in the relationship between the CRRT-to-core temperature gradient (ΔT°) and HIRRT risk.
• To explore the impact of extracorporeal cooling on hemodynamic parameters during CRRT.

Main Methods:

• Ancillary analysis of a prospective study (NCT03139123) involving 42 patients with acute kidney injury receiving CRRT.
• Collected T°_CRRT, T°_CORE, and hemodynamic parameters hourly; calculated ΔT° (T°_CRRT - T°_CORE).
• Employed exploratory mediation analysis to assess the effect of ΔT° on HIRRT, mediated by CO and mean arterial pressure (MAP).

Main Results:

• Decreasing ΔT° (extracorporeal cooling) correlated with higher heart rate, CO, and MAP, and lower norepinephrine requirements.
• Univariate analysis showed a significant association between lower ΔT° and reduced HIRRT risk (P < 0.01).
• Mediation analysis revealed that ΔT° ≤0°C decreased HIRRT probability by 7% (1%-14%), with significant indirect effects through MAP (5% [2%-7%]) and CO (4% [1%-5%]).

Conclusions:

• Setting CRRT circuit temperature below core temperature is associated with reduced HIRRT risk.
• Improvements in MAP and CO may mediate the protective effect of extracorporeal cooling against hemodynamic instability during CRRT.