Static versus dynamic respiratory mechanics for setting the ventilator.
The lower inflection point (LIP) of the inspiratory limb of a static pressure-volume (PV) loop is assumed to indicate the pressure at which most lung units are recruited. The LIP is determined by a static manoeuvre with a PV-history that is different from the PV-history of the actual ventilation. In nine surfactant-deficient piglets, information to allow setting PEEP and VT was obtained, both from the PV-curve and also during ongoing ventilation from the dynamic compliance relationship. According to LIP, PEEP was set at 20 (95% confidence interval 17-22) cm H2O. Volume-dependent dynamic compliance suggested a PEEP reduction (to 15 (13-18) cm H2O). Pulmonary gas exchange remained satisfactory and this change resulted in reduced mechanical stress on the respiratory system, indirectly indicated by volume-dependent compliance being consistently great during the entire inspiration.
Lichtwarck-Aschoff
M
M
Department of Anesthesiology and Intensive Care, University Hospital, Uppsala, Sweden.
Kessler
V
V
Sjöstrand
U H
UH
Hedlund
A
A
Mols
G
G
Rubertsson
S
S
Markström
A M
AM
Guttmann
J
J
D000818:Animals; D018893:Bronchoalveolar Lavage; D005260:Female; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D011175:Positive-Pressure Respiration / Q000379:methods*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D011663:Pulmonary Surfactants / Q000172:deficiency; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics / Q000502:physiology*; D013314:Stress, Mechanical; D013552:Swine
D011663:Pulmonary Surfactants