Time course of haemodynamic, respiratory and inflammatory disturbances induced by experimental acute pulmonary polystyrene microembolism.
OBJECTIVE
The time course of cardiopulmonary alterations after pulmonary embolism has not been clearly demonstrated and nor has the role of systemic inflammation on the pathogenesis of the disease. This study aimed to evaluate over 12 h the effects of pulmonary embolism caused by polystyrene microspheres on the haemodynamics, lung mechanics and gas exchange and on interleukin-6 production.


METHODS
Ten large white pigs (weight 35-42 kg) had arterial and pulmonary catheters inserted and pulmonary embolism was induced in five pigs by injection of polystyrene microspheres (diameter approximately 300 micromol l(-1)) until a value of pulmonary mean arterial pressure of twice the baseline was obtained. Five other animals received only saline. Haemodynamic and respiratory data and pressure-volume curves of the respiratory system were collected. A bronchoscopy was performed before and 12 h after embolism, when the animals were euthanized.


RESULTS
The embolism group developed hypoxaemia that was not corrected with high oxygen fractions, as well as higher values of dead space, airway resistance and lower respiratory compliance levels. Acute haemodynamic alterations included pulmonary arterial hypertension with preserved systemic arterial pressure and cardiac index. These derangements persisted until the end of the experiments. The plasma interleukin-6 concentrations were similar in both groups; however, an increase in core temperature and a nonsignificant higher concentration of bronchoalveolar lavage proteins were found in the embolism group.


CONCLUSIONS
Acute pulmonary embolism induced by polystyrene microspheres in pigs produces a 12-h lasting hypoxaemia and a high dead space associated with high airway resistance and low compliance. There were no plasma systemic markers of inflammation, but a higher central temperature and a trend towards higher bronchoalveolar lavage proteins were found.
Dolci
Daniel T
DT
Intensive Care and Anesthesiology Research Laboratory, Research and Education Institute, Hospital Sírio-Libanês, São Paulo, Brazil.
Fuentes
Carolina B
CB
Rolim
Denise
D
Park
Marcelo
M
Schettino
Guilherme P P
GP
Azevedo
Luciano C P
LC
D000208:Acute Disease; D000818:Animals; D001794:Blood Pressure; D001992:Bronchoalveolar Lavage Fluid; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D007249:Inflammation / Q000139:chemically induced*; D015850:Interleukin-6 / Q000378:metabolism; D008168:Lung / Q000473:pathology; D008863:Microspheres; D011137:Polystyrenes / Q000009:adverse effects*; D011655:Pulmonary Embolism / Q000139:chemically induced* / Q000473:pathology*; D011659:Pulmonary Gas Exchange; D013552:Swine; D013997:Time Factors
D015850:Interleukin-6; D011137:Polystyrenes