Abstract: TH-PO1127

Relationship between Central Venous, Peripheral Venous, and Arterial Potassium in the ICU

Session Information

Category: Fluid, Electrolytes, and Acid-Base

  • 704 Fluid, Electrolyte, Acid-Base Disorders

Authors

  • Treger, Richard M., VA Greater Los Angeles Healthcare System, Los Angeles, California, United States
  • Hsieh, Caleb, Olive View-UCLA Medical Center, Sylmar, California, United States
  • Grogan, Tristan, UCLA, Los Angeles, California, United States
  • Kamangar, Nader, Olive View-UCLA Medical Center, Sylmar, California, United States
Background

As shown in small studies evaluating regional hypoperfusion, venous potassium concentration (K+) may better reflect interstitial and tissue K+ than arterial values, and thus better predict serious cardiac manifestations of hyperkalemia. Moreover, because central veins drain a much greater tissue mass (muscle and splanchnic) than peripheral veins, discrepancies between peripheral venous (PV), central venous (CV), and arterial (Art) K+ may exist, especially in states of global hypoperfusion such as sepsis. No prior study has examined this relationship.

Methods

Art, CV, and PV samples were prospectively obtained within 10 minutes of each other from single-center adult medical ICU patients.

Results

51 paired samples from 23 patients were included. The correlations between Art-PV K+, Art-CV K+ and CV lactate (Figure) were not statistically significant (p = 0.60 and 0.99, respectively). The correlations between PV and Art K+, as well as CV and Art K+ yielded an R2 of 0.83 and 0.83, respectively. Bland-Altman plots of Art K+ and PV K+, as well as Art K+ and CV K+ showed 95% limits of agreement of -0.42 to 0.35 and -0.43 to 0.51, respectively.

Conclusion

In medical ICU patients with global hypoperfusion, CV K+ was not different from that of Art and PV K+ and did not correlate with serum lactate. This disproved our hypothesis that in global hypoperfusion CV blood would demonstrate higher K+ and better reflect tissue K+ compared with Art blood. In fact, CV and PV K+ showed high correlation and strong agreement with Art K+ and can be used interchangeably. This contrasts with prior studies of regional hypoperfusion that demonstrated a higher K+ in venous blood relative to arterial blood, reflective of local interstitial and tissue K+ levels. Our results likely did not demonstrate this because of augmented intracellular K+ shifting and CV system dilution of K+ in global hypoperfusion.

Figure: Correlation between CV Lactate and Art-CV Potassium

Funding

  • Veterans Affairs Support