The effects of severe hemoconcentration on acid-base equilibrium in critically ill patients: the forgotten role of buffers in whole blood

J Crit Care. 2020 Jun:57:177-184. doi: 10.1016/j.jcrc.2020.02.016. Epub 2020 Mar 4.

Abstract

Purpose: Idiopathic Systemic Capillary Leak Syndrome (ISCLS) is a paroxysmal permeability disorder characterized by abrupt onset of shock and hemoconcentration due to massive shift of fluids and proteins from the intravascular to the interstitial compartment. We hypothesize that increased hemoglobin concentration has a pivotal role in the acid-base imbalance during life-threatening crises.

Materials and methods: Analysis of the acid-base balance fluctuations during six severe ISCLS flares admitted to ICU of a referral center for ISCLS.

Results: Acid-base equilibrium was assessed for plasma and the whole blood by single and multicompartmental models. The acute phase of ISCLS was characterized by shock, hypoalbuminemia, severe hemoconcentration, and acidosis. The physical-chemical approach for plasma found a remarkable component of unmeasured anions (SIG) during the acute phase. After correction of the physical-chemical model for the whole blood, the SIG variations disappeared because the buffer role of hemoglobin was relevant.

Conclusion: Hemoglobin has a remarkable role in buffering metabolic acidosis during the shock phase of ISCLS. In these circumstances, the assessment of acid-base equilibrium in plasma alone may overestimate unmeasured anions. On the contrary, the physical-chemical model corrected for whole blood better explains the metabolic component of acid-base imbalance when marked shift of hemoglobin concentration occurs.

Keywords: Acid-base balance; Acidosis; Hemoconcentration; Hypoalbuminemia; Idiopathic systemic capillary leak syndrome; Shock.

Publication types

  • Observational Study

MeSH terms

  • Acid-Base Equilibrium
  • Acid-Base Imbalance / blood*
  • Acidosis / therapy
  • Arterial Pressure
  • Buffers
  • Capillary Leak Syndrome / blood*
  • Capillary Leak Syndrome / diagnosis*
  • Critical Illness*
  • Hematocrit
  • Hemoglobins / analysis*
  • Humans
  • Hypoalbuminemia / complications
  • Ions
  • Male
  • Plasma
  • Retrospective Studies
  • Shock / therapy*

Substances

  • Buffers
  • Hemoglobins
  • Ions