On the Intensity of the Microvascular Magnetic Field in Normal State and Septic Shock

TL;DR

The study compares magnetic field intensities in microcirculation between healthy individuals and those with septic shock, finding stronger red blood cell magnetic fields in septic shock patients.

Contribution

This study introduces novel measurements of magnetic field intensities in microcirculation and explores their implications in septic shock.

Findings

HRBC was significantly stronger in septic shock patients compared to steady-state individuals.

HCAP and FCAP showed no significant differences between the two groups.

HRBC was associated with De Backer score and venous–arterial carbon dioxide difference in septic shock patients.

Abstract

Background: Capillary tortuosity is a morphological variant of microcirculation. However, the mechanisms by which tortuous vessels meet metabolic requirements in health and disease remain unknown. We recently reported that capillary tortuosity score (CTS) is significantly higher in patients with septic shock than in steady-state individuals, and that CTS is significantly associated with alveolar-to-arterial oxygen (A-a O2) gradient and oxygen debt in septic shock patients. Objective: We aimed to investigate the characteristics of the magnetic fields in the sublingual microcirculation of individuals with normal physiology and patients with septic shock. Methods: Systemic hemodynamics were recorded, and sublingual microcirculation was monitored using sidestream dark field (SDF+) imaging. The number of capillary red blood cells (NRBC), the intensity of the magnetic field of a red blood cell (HRBC), the intensity of the magnetic field of each capillary (HCAP), and the intensity with which the magnetic field of a capillary acts on an RBC (FCAP) were calculated. Results: Significant differences in macro- and microhemodynamic variables were observed between the two groups. Although NRBC was significantly higher in individuals with steady-state physiology [87.4 (87.12) vs. 12.23 (6.9)], HRBC was significantly stronger in patients with septic shock [5.9 × 10−16 (6.9 × 10−16) A m−1 vs. 1.6 × 10−15 (1.4 × 10−15) A m−1]. No significant difference was observed in HCAP [2.16 × 10−14 (2.17 × 10−14) A m−1 vs. 1.34 × 10−14 (1.23 × 10−14) A m−1] and FCAP [1.66 × 10−24 (3.36 × 10−24) A m−1 vs. 6.44 × 10−25 (1.1 × 10−24) A m−1] between the two groups. In patients with septic shock, HRBC was associated with De Backer score (rho = −0.608) and venous–arterial carbon dioxide difference (rho = 0.569). In the same group, HCAP was associated with convective oxygen flow (rho = 0.790) and oxygen extraction ratio (rho = −0.596). Also, FCAP was significantly associated with base deficit (rho = 0.701), A-a O2 gradient (rho = 0.658), and oxygen debt (rho = −0.769). Conclusions: Despite the microcirculatory impairment in patients with septic shock, HRBC was significantly stronger in that group than in steady-state individuals. Also, HCAP and FCAP were comparable between the two groups. Tortuous vessels may function as biomagnetic coils that amplify RBC-induced magnetic fields, enhancing perfusion and oxygenation of adjacent tissues.

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