Simultaneous monitoring of intratidal compliance and resistance in mechanically ventilated piglets: A feasibility study in two different study groups.
Compliance measures the force counteracting parenchymal lung distension. In mechanical ventilation, intratidal compliance-volume (C(V))-profiles therefore change depending on PEEP, tidal volume (VT), and underlying mechanical lung properties. Resistance counteracts gas flow through the airways. Due to anatomical linking between parenchyma and airways, intratidal resistance-volume (R(V))-profiles are hypothesised to change in a non-linear way as well. We analysed respiratory system mechanics in fifteen piglets with lavage-induced lung injury and nine healthy piglets ventilated at different PEEP/VT-settings. In healthy lungs, R(V)-profiles remained mostly constant and linear at all PEEP-settings whereas the shape of the C(V)-profiles showed an increase toward a maximum followed by a decrease (small PEEP) or volume-dependent decrease (large PEEP). In the lavage group, a large drop in resistance at small volumes and slow decrease toward larger volumes was found for small PEEP/VT-settings where C(V)-profiles revealed a volume-dependent increase (small PEEP) or a decrease (large PEEP and large VT). R(V)-profiles depend characteristically on PEEP, VT, and possibly whether lungs are healthy or not. Curved R(V)-profiles might indicate pathological changes in the underlying mechanical lung properties and/or might be a sign of derecruitment.
Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Germany. Electronic address: sarah.buehler@uniklinik-freiburg.de.
Sarah
S
Buehler
Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Germany. Electronic address: stefan.schumann@uniklinik-freiburg.de.
Stefan
S
Schumann
Department of Surgical Sciences, Uppsala University, Sweden. Electronic address: vimlati.laszlo@bredband2.com.
László
L
Vimláti
Department of Surgical Sciences, Uppsala University, Sweden. Electronic address: m.lichtwarck-aschoff@gmx.de.
Michael
M
Lichtwarck-Aschoff
Department of Anesthesiology and Intensive Care Medicine, Division of Experimental Anesthesiology, University Medical Center Freiburg, Germany. Electronic address: josef.guttmann@uniklinik-freiburg.de.
Josef
J
Guttmann
D000403:Airway Resistance; D000818:Animals; D005240:Feasibility Studies; D008170:Lung Compliance; D008991:Monitoring, Physiologic / Q000379:methods*; D011175:Positive-Pressure Respiration / Q000379:methods*; D015656:Respiratory Mechanics; D013552:Swine
Compliance; Mechanical ventilation; PEEP; Resistance; Respiratory mechanics