Network autonomic analysis of post-acute sequelae of COVID-19 and postural tachycardia syndrome 2022 Novak et al

Abstract

Background
The autonomic nervous system (ANS) is a complex network where sympathetic and parasympathetic domains interact inside and outside of the network. Correlation-based network analysis (NA) is a novel approach enabling the quantification of these interactions. The aim of this study is to assess the applicability of NA to assess relationships between autonomic, sensory, respiratory, cerebrovascular, and inflammatory markers on post-acute sequela of COVID-19 (PASC) and postural tachycardia syndrome (POTS).

Methods
In this retrospective study, datasets from PASC (n = 15), POTS (n = 15), and matched controls (n = 11) were analyzed. Networks were constructed from surveys (autonomic and sensory), autonomic tests (deep breathing, Valsalva maneuver, tilt, and sudomotor test) results using heart rate, blood pressure, cerebral blood flow velocity (CBFv), capnography, skin biopsies for assessment of small fiber neuropathy (SFN), and various inflammatory markers. Networks were characterized by clusters and centrality metrics.

Results
Standard analysis showed widespread abnormalities including reduced orthostatic CBFv in 100%/88% (PASC/POTS), SFN 77%/88%, mild-to-moderate dysautonomia 100%/100%, hypocapnia 87%/100%, and elevated inflammatory markers. NA showed different signatures for both disorders with centrality metrics of vascular and inflammatory variables playing prominent roles in differentiating PASC from POTS.

Conclusions
NA is suitable for a relationship analysis between autonomic and nonautonomic components. Our preliminary analyses indicate that NA can expand the value of autonomic testing and provide new insight into the functioning of the ANS and related systems in complex disease processes such as PASC and POTS.

Open access, https://link.springer.com/article/10.1007/s10072-022-06423-y

 

That one has always struck me as interesting: low CO2 blood level. It would be an expected counterpart to poor tissue oxygenation. If cells can't efficiently utilize the oxygen, they would be producing fewer metabolic byproducts.

It's commonly found in respiratory diseases like pneumonia, but COVID mostly does not lead to typical pneumonia, not the standard hardening of lung tissue, and seems mostly a vascular disease. So many interesting leads to follow. Many of them known for decades. It's so disappointing how little investigative work there is, working down all the pieces of the puzzle in an organized process that builds on itself.

They keep popping up and just never get followed in a rigorous process.

 

When I saw hypocapnia I thought maybe dysautonomia. Perhaps the brain is telling the lungs to breathe excessively.