Continuous Noninvasive Hemoglobin Monitoring Reflects the Development of Acute Hemodilution After Consecutive Fluid...

Area of Science:

• Critical Care Medicine
• Hemodynamics
• Fluid Management

Background:

• Goal-directed therapy (GDT) often uses fluid challenges (FCs) to maximize stroke volume (SV).
• Fluid administration can cause hemodilution, potentially decreasing oxygen delivery (DO2).

Purpose of the Study:

• To evaluate continuous noninvasive hemoglobin (SpHb) monitoring for detecting acute hemodilution after graded fluid administration.

Main Methods:

• 40 patients received 250 mL colloid FCs, repeated up to 3 times if SV increased by ≥10%.
• Hemoglobin (BHb, SpHb), SV, cardiac output (CO), and DO2 were measured after each FC.

Main Results:

• 60% of FCs increased SV by ≥10%.
• While initial FCs increased CO and DO2, subsequent FCs led to significant decreases in SpHb, BHb, and DO2.
• SpHb and BHb decreased significantly, with SpHb and BHb concordance rates reaching 100% after 750 mL of colloids.

Conclusions:

• Fluid loading can cause significant decreases in SpHb and BHb.
• When FCs do not increase SV, DO2 decreases due to hemodilution.
• Continuous SpHb monitoring reliably detects acute hemodilution, particularly after ≥500 mL of colloids.