by Scaramuzzo, Gaetano; Spadaro, Savino; Dalla Corte,
Francesca; Waldmann, Andreas D.; Böhm, Stephan H.; Ragazzi, Riccardo;
Marangoni, Elisabetta; Grasselli, Giacomo; Pesenti, Antonio; Volta, Carlo
Alberto; Mauri, Tommaso
Critical Care
Medicine: August 2020 -
Volume 48 - Issue 8 - p 1148-1156
Objectives:
Different techniques exist to select personalized positive
end-expiratory pressure in patients affected by the acute respiratory distress
syndrome. The positive end-expiratory transpulmonary pressure strategy aims to
counteract dorsal lung collapse, whereas electrical impedance tomography could
guide positive end-expiratory pressure selection based on optimal homogeneity
of ventilation distribution. We compared the physiologic effects of positive
end-expiratory pressure guided by electrical impedance tomography versus
transpulmonary pressure in patients affected by acute respiratory distress
syndrome.
Design: Cross-over prospective physiologic study.
Setting: Two academic ICUs.
Patients: Twenty ICU patients affected by acute respiratory
distress syndrome undergoing mechanical ventilation.
Intervention:
Patients monitored by an esophageal catheter and a 32-electrode electrical
impedance tomography monitor underwent two positive end-expiratory pressure
titration trials by randomized cross-over design to find the level of positive
end-expiratory pressure associated with: 1) positive end-expiratory
transpulmonary pressure (PEEPPL) and 2) proportion of poorly or nonventilated
lung units (Silent Spaces) less than or equal to 15% (PEEPEIT). Each positive end-expiratory
pressure level was maintained for 20 minutes, and afterward, lung mechanics,
gas exchange, and electrical impedance tomography data were collected.
Measurements and Main Results: PEEPEIT and PEEPPL differed in all patients, and
there was no correlation between the levels identified by the two methods (Rs =
0.25; p = 0.29). PEEPEIT determined a more homogeneous distribution of
ventilation with a lower percentage of dependent Silent Spaces (p = 0.02),
whereas PEEPPL was characterized by lower airway—but not transpulmonary—driving
pressure (p = 0.04). PEEPEIT was significantly higher than PEEPPL in subjects
with extrapulmonary acute respiratory distress syndrome (p = 0.006), whereas
the opposite was true for pulmonary acute respiratory distress syndrome (p =
0.03).
Conclusions: Personalized positive end-expiratory pressure
levels selected by electrical impedance tomography– and transpulmonary
pressure–based methods are not correlated at the individual patient level.
PEEPPL is associated with lower dynamic stress, whereas PEEPEIT may help to
optimize lung recruitment and homogeneity of ventilation. The underlying
etiology of acute respiratory distress syndrome could deeply influence results
from each method.
No comments:
Post a Comment