Transient mechanical benefits of a deep inflation in the injured mouse lung.
The lasting effects of a recruitment maneuver (RM) in the injured lung are not well characterized. We speculated that the reduction in respiratory elastance (H) after a deep inflation (DI) is transient in nature and should be sustained longer at higher positive end-expiratory pressure (PEEP). Thirteen ventilated mice were given 2 DIs at various levels of PEEP before and after saline lavage. Forced oscillations were used to measure H periodically over 7 min after the DIs. Time constants (tau) were estimated for the post-DI recovery in H. Values for tau before lavage (80-115 s) were reduced after lavage (13-30 s) at all levels of PEEP (P = 0.0001). PEEP did not significantly influence tau before or after lavage. The plateau level and total recovery in H after a DI were significantly influenced by PEEP and lavage (P < 0.0001). Our results suggest that for a DI to be beneficial in the injured mouse lung, it may have to be applied several times a minute.
Allen
Gilman
G
Department of Medicine, Vermont Lung Center, University of Vermont, Burlington, Vermont 05405, USA. gballen@zoo.uvm.edu
Lundblad
Lennart K A
LK
Parsons
Polly
P
Bates
Jason H T
JH
D000818:Animals; D004548:Elasticity; D005260:Female; D001239:Inhalation / Q000502:physiology*; D008168:Lung / Q000503:physiopathology; D008171:Lung Diseases / Q000503:physiopathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011175:Positive-Pressure Respiration; D020127:Recovery of Function; D015656:Respiratory Mechanics; D013997:Time Factors