Deoxygenation Trends and Their Multivariate Association with Self-Reported Fatigue in Post-COVID Syndrome

Area of Science:

• Cardiovascular and neurological sciences
• Physiology
• Medical diagnostics

Background:

• Post-COVID-19 syndrome (PCS) can involve debilitating fatigue and cardiovascular/neurological symptoms.
• A subgroup of PCS patients experiences impaired microcirculation, contributing to severe functional limitations.
• Understanding these physiological changes is crucial for effective patient management.

Purpose of the Study:

• To investigate local deoxygenation using near-infrared regional spectroscopy (NIRS) in PCS patients during light exercise.
• To assess the association between self-reported fatigue and deoxygenation dynamics in PCS.
• To identify potential objective markers for PCS subgroups.

Main Methods:

• 150 participants (100 PCS patients, 50 controls) underwent NIRS measurements during a stress ball exercise and recovery.
• Post-exertional malaise (PEM) was evaluated using validated fatigue scoring systems (FACIT, Chalder, Bell) and Canadian Criteria.
• NIRS monitored local muscle oxygenation changes in response to physical stress.

Main Results:

• PCS patients reported significant fatigue across multiple scales.
• A statistically significant decrease in deoxygenation peaks was observed in PCS patients compared to controls (p = 0.0002).
• Multivariate analysis revealed a subgroup of PCS patients with a strong correlation between severe fatigue and restricted oxygenation dynamics.

Conclusions:

• NIRS can detect deoxygenation deficits in PCS patients, even those with moderate to severe impairment.
• Light exercise protocols combined with NIRS show promise for objective assessment of microcirculatory dysfunction in PCS.
• This approach may aid in differentiating PCS subgroups and guiding therapeutic strategies.