Assessing the relationship of respiratory muscle strength and cytokine status in patients with community-acquired pneumonia

Abstract

Aim. Assessment of the role of cytokine-mediated changes in the development of respiratory muscle (RM) dysfunction in patients with community-acquired pneumonia (СAP). Methods. 84 men aged 18 – 26 years with a median of age 19.5 [18.4; 22.8]. Mild to moderate CAP (MCAP) was diagnosed in 62 (73.8%) patients and severe (SCAP) in 22 (26.2%). The expiratory (MEP, MRPDout) and inspiratory (MIP, MRPDin. SNIP) strength indices of RM were recorded on a MicrоRPM apparatus (CareFusion, UK). The severity of endogenous intoxication was verified using the following indices: hematologic (HII), leukocyte (LII), and nuclear. Serum concentrations of interleukins-2, -8, -10, basic fibroblast growth factor, transforming growth factor-beta, tumor necrosis factor-alpha (TNF-α), and a soluble receptor for TNF-α. Data processing was performed by cluster and correlation analysis methods. Results. Three clusters of patients with CAP were identified by the characteristic combinations of indicators of RM strength, endogenous intoxication, and cytokine status. The first cluster had MCAP, the second – both MCAP and SCAP, the third – SCAP. In the first cluster, dysfunction of expiratory RM prevailed, and in the second and third – dysfunction of inspiratory RM. In the midst of CAP, significant negative correlations of RM strength indicators with LII, HII, TNF-α, IL-10, IL-8, and IL-2 levels were recorded. The endogenous intoxication indices reached control values in all patients during recovery. The first cluster showed a decrease in the level of analyzed cytokines against isolated dysfunction of expiratory RM. The second cluster showed a tendency toward restoration of TNF-α and IL-8 levels, and only their SNIP index was normal. The third cluster showed minimal medians of RM strength against the continuing imbalance in the profile of pro- and anti-inflammatory cytokines during recovery. Conclusion. RM dysfunction in CAP is associated with cytokine-mediated dysfunction. The degree of cytokine involvement in this process depends on the severity of endogenous intoxication and the volume of alveolar inflammation.