tetano
Editor, Senior Moderator
Microcirculation
. 2025 Jul;32(5):e70014.
doi: 10.1111/micc.70014. COVID-19 Patients Have Peripheral Microvascular Dysfunction and Tissue Hypoxia in Spite of Successful Treatment of Lung Failure: A Proof of Concept Study
Knut Kvernebo[SUP] 1 2 3 [/SUP], L Liv Kristin Wikslund[SUP] 1 4 [/SUP], Kamila Drezek[SUP] 5 [/SUP], Andrea Jaramillo[SUP] 5 [/SUP], Luigino Capone[SUP] 3 [/SUP], Maged Helmy[SUP] 3 [/SUP], Yunong Zhao[SUP] 5 [/SUP], Aaron Aguirre[SUP] 6 [/SUP], David D'Alessandro[SUP] 5 [/SUP]
Affiliations
Background: Availability of oxygen (O[SUB]2[/SUB]) is essential for life and function of all cells of the human body (n ≈ 10[SUP]13[/SUP]-10[SUP]14[/SUP] cells). COVID-19 patients often have impaired lung function with compromised oxygen uptake, but little is known about microvascular oxygen delivery and tissue oxygenation.
Objectives: Use the Oxygen Delivery Index (ODIN) concept to assess peripheral microvascular regulation and oxygen extraction in COVID-19 patients.
Methods: The ODIN concept includes two technologies (diffuse reflectance spectroscopy-DRS and computer assisted microscopy-CAM) for data acquisition from subepidermal nutritive capillaries. Output parameters are microvascular oxygen saturation (SmvO[SUB]2[/SUB]) and functional capillary density (FCD).
Results: Forty patients hospitalized for COVID-19 grouped into early discharge (< 7 days, n = 11), severe (beyond 7 days, n = 24) and non-survivors (n = 5), and healthy controls (n = 23) were examined. Microvascular oxygen saturation (SmvO[SUB]2[/SUB]) and the corresponding O[SUB]2[/SUB] extraction (SaO[SUB]2[/SUB]-SmvO[SUB]2[/SUB]) was 56% ± 4%/42% ± 9% (mean ± SD) in healthy controls (n = 11), 61 ± 10/37 ± 10 for historic controls (n = 12), significantly different (p < 0.01) as compared with all COVID-19 groups (early discharge: 40% ± 13%/54% ± 13%, severe: 34% ± 15%/60% ± 15%, non-survivors 22% ± 15%/73% ± 16%). FCD expressed as the relative number of red pixels (belonging to a capillary erythrocyte) in a CAM frame were reduced in alle patient groups as compared to historic controls (p < 0⋅05).
Conclusion: Results show skin microvascular dysregulation and tissue hypoxia in patients, indicative of hypoxia also in other tissues. We hypothesize that tissue hypoxia is a cause of reversible and non-reversible long COVID-19 symptoms and of mortality.
Keywords: COVID‐19; ODIN concept; diffuse reflectance spectroscopy; microcircualtion; tissue oxygenation.
. 2025 Jul;32(5):e70014.
doi: 10.1111/micc.70014. COVID-19 Patients Have Peripheral Microvascular Dysfunction and Tissue Hypoxia in Spite of Successful Treatment of Lung Failure: A Proof of Concept Study
Knut Kvernebo[SUP] 1 2 3 [/SUP], L Liv Kristin Wikslund[SUP] 1 4 [/SUP], Kamila Drezek[SUP] 5 [/SUP], Andrea Jaramillo[SUP] 5 [/SUP], Luigino Capone[SUP] 3 [/SUP], Maged Helmy[SUP] 3 [/SUP], Yunong Zhao[SUP] 5 [/SUP], Aaron Aguirre[SUP] 6 [/SUP], David D'Alessandro[SUP] 5 [/SUP]
Affiliations
- PMID: 40598822
- DOI: 10.1111/micc.70014
Background: Availability of oxygen (O[SUB]2[/SUB]) is essential for life and function of all cells of the human body (n ≈ 10[SUP]13[/SUP]-10[SUP]14[/SUP] cells). COVID-19 patients often have impaired lung function with compromised oxygen uptake, but little is known about microvascular oxygen delivery and tissue oxygenation.
Objectives: Use the Oxygen Delivery Index (ODIN) concept to assess peripheral microvascular regulation and oxygen extraction in COVID-19 patients.
Methods: The ODIN concept includes two technologies (diffuse reflectance spectroscopy-DRS and computer assisted microscopy-CAM) for data acquisition from subepidermal nutritive capillaries. Output parameters are microvascular oxygen saturation (SmvO[SUB]2[/SUB]) and functional capillary density (FCD).
Results: Forty patients hospitalized for COVID-19 grouped into early discharge (< 7 days, n = 11), severe (beyond 7 days, n = 24) and non-survivors (n = 5), and healthy controls (n = 23) were examined. Microvascular oxygen saturation (SmvO[SUB]2[/SUB]) and the corresponding O[SUB]2[/SUB] extraction (SaO[SUB]2[/SUB]-SmvO[SUB]2[/SUB]) was 56% ± 4%/42% ± 9% (mean ± SD) in healthy controls (n = 11), 61 ± 10/37 ± 10 for historic controls (n = 12), significantly different (p < 0.01) as compared with all COVID-19 groups (early discharge: 40% ± 13%/54% ± 13%, severe: 34% ± 15%/60% ± 15%, non-survivors 22% ± 15%/73% ± 16%). FCD expressed as the relative number of red pixels (belonging to a capillary erythrocyte) in a CAM frame were reduced in alle patient groups as compared to historic controls (p < 0⋅05).
Conclusion: Results show skin microvascular dysregulation and tissue hypoxia in patients, indicative of hypoxia also in other tissues. We hypothesize that tissue hypoxia is a cause of reversible and non-reversible long COVID-19 symptoms and of mortality.
Keywords: COVID‐19; ODIN concept; diffuse reflectance spectroscopy; microcircualtion; tissue oxygenation.