Effects of propofol on respiratory mechanic and lung histology in normal rats.
BACKGROUND
Propofol is able to reduce airway resistance in lungs with previous airway constriction. The aim of this study was to evaluate the effects of propofol on respiratory mechanics in normal rats and to correlate these parameters with lung histology, to define the sites of action of propofol.


METHODS
Sixteen Wistar rats were divided into two groups of eight animals. Rats were sedated (diazepam) and anaesthetized with pentobarbital sodium (C) or propofol (P), and paralysed. Respiratory system, lung, and chest wall resistive, elastic, and viscoelastic/inhomogeneous pressures were computed using the end-inflation occlusion method.


RESULTS
Lung resistive pressure was smaller in group P (0.29 kPa (0.05)) than group C (0.37 kPa (0.04)) (P=0.007). The internal diameter of the central airways was greater in group P than C (P=0.01).


CONCLUSIONS
Propofol acts at the airway level decreasing respiratory system and lung impedances as a result of central airway dilation.
Peratoner
A
A
Laboratory of Respiration Physiology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Ilha do Fundão, 21949-900, Rio de Janeiro, Brazil.
Nascimento
C S
CS
Santana
M C E
MC
Cadete
R A
RA
Negri
E M
EM
Gullo
A
A
Rocco
P R M
PR
Zin
W A
WA
D000403:Airway Resistance / Q000187:drug effects; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D005260:Female; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D010424:Pentobarbital / Q000494:pharmacology; D015742:Propofol / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D015656:Respiratory Mechanics / Q000187:drug effects*
D018686:Anesthetics, Intravenous; D010424:Pentobarbital; D015742:Propofol