Microcirculatory dysfunction and dead-space ventilation in early ARDS: a hypothesis-generating observational study.

Autor: Ospina-Tascón GA; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia. gusospin@gmail.com.; Translational Medicine Laboratory for Critical Care and Advanced Trauma Surgery, Fundación Valle del Lili - Universidad Icesi, Cali, Colombia. gusospin@gmail.com., Bautista DF; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia., Madriñán HJ; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia., Valencia JD; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia., Bermúdez WF; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia., Quiñones E; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia., Calderón-Tapia LE; Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia., Hernandez G; Departamento de Medicina Intensiva, Pontificia Universidad Católica de Chile, Santiago, Chile., Bruhn A; Departamento de Medicina Intensiva, Pontificia Universidad Católica de Chile, Santiago, Chile., De Backer D; Department of Intensive Care, CHIREC Hospitals, Université Libre de Bruxelles, Brussels, Belgium.
Jazyk: angličtina
Zdroj: Annals of intensive care [Ann Intensive Care] 2020 Mar 24; Vol. 10 (1), pp. 35. Date of Electronic Publication: 2020 Mar 24.
DOI: 10.1186/s13613-020-00651-1
Abstrakt: Background: Ventilation/perfusion inequalities impair gas exchange in acute respiratory distress syndrome (ARDS). Although increased dead-space ventilation (V D /V T ) has been described in ARDS, its mechanism is not clearly understood. We sought to evaluate the relationships between dynamic variations in V D /V T and extra-pulmonary microcirculatory blood flow detected at sublingual mucosa hypothesizing that an altered microcirculation, which is a generalized phenomenon during severe inflammatory conditions, could influence ventilation/perfusion mismatching manifested by increases in V D /V T fraction during early stages of ARDS.
Methods: Forty-two consecutive patients with early moderate and severe ARDS were included. PEEP was set targeting the best respiratory-system compliance after a PEEP-decremental recruitment maneuver. After 60 min of stabilization, hemodynamics and respiratory mechanics were recorded and blood gases collected. V D /V T was calculated from the CO 2 production ([Formula: see text]) and CO 2 exhaled fraction ([Formula: see text]) measurements by volumetric capnography. Sublingual microcirculatory images were simultaneously acquired using a sidestream dark-field device for an ulterior blinded semi-quantitative analysis. All measurements were repeated 24 h after.
Results: Percentage of small vessels perfused (PPV) and microcirculatory flow index (MFI) were inverse and significantly related to V D /V T at baseline (Spearman's rho = - 0.76 and - 0.63, p < 0.001; R 2  = 0.63, and 0.48, p < 0.001, respectively) and 24 h after (Spearman's rho = - 0.71, and - 0.65; p < 0.001; R 2  = 0.66 and 0.60, p < 0.001, respectively). Other respiratory, macro-hemodynamic and oxygenation parameters did not correlate with V D /V T . Variations in PPV between baseline and 24 h were inverse and significantly related to simultaneous changes in V D /V T (Spearman's rho = - 0.66, p < 0.001; R 2  = 0.67, p < 0.001).
Conclusion: Increased heterogeneity of microcirculatory blood flow evaluated at sublingual mucosa seems to be related to increases in V D /V T , while respiratory mechanics and oxygenation parameters do not. Whether there is a cause-effect relationship between microcirculatory dysfunction and dead-space ventilation in ARDS should be addressed in future research.
Databáze: MEDLINE
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