Mechanical ventilation may increase susceptibility to the development of bacteremia.
Crit Care Med
; 31(5): 1429-34, 2003 May.
Article
in En
| MEDLINE
| ID: mdl-12771614
ABSTRACT
OBJECTIVE:
We examined the hypothesis that mechanical ventilation with a potentially injurious strategy would predispose animals to the detrimental effects of subsequent instillation of bacteria.DESIGN:
Interventional animal study.SETTING:
A university hospital research laboratory.SUBJECTS:
Fifty Sprague-Dawley male rats.INTERVENTIONS:
Rats were anesthetized and randomized to receive a protective (tidal volume 7 mL/kg, positive end-expiratory pressure 5 cm H(2)O, n = 25) or an injurious ventilatory strategy (tidal volume 21 mL/kg, zero positive end-expiratory pressure, n = 25). Hemodynamics were similar during the 1-hr ventilation period in the two groups. Animals were then disconnected from the ventilator and Pseudomonas aeruginosa was instilled intratracheally before extubation. Thereafter, animals breathed spontaneously; mortality rate was assessed up to 48 hrs, at which time the animals were killed. MEASUREMENTS AND MAINRESULTS:
The 48-hr mortality rate was 28% in the protective group and 40% in the injurious group (p = not significant). A positive bacterial culture from the lung was obtained in 56% of the surviving rats in the low tidal volume group and 67% in the high tidal volume group (p =.059). A positive blood bacterial culture was found in 11% of the low tidal volume group and 33% in the high tidal volume group (p <.05). The absolute bacterial count in the blood was lower in the low tidal volume group compared with the high tidal volume group (p <.05). Concentrations of blood tumor necrosis factor-alpha and macrophage inflammatory protein-2, and lung macrophage inflammatory protein-2 at 48 hrs were significantly higher in the low tidal volume group than in the high tidal volume group.CONCLUSIONS:
An injurious ventilatory strategy predisposes animals to subsequent bacteremia associated with an impaired host defense reflected by cytokine response.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pseudomonas Infections
/
Respiration, Artificial
/
Cross Infection
/
Positive-Pressure Respiration
/
Bacteremia
/
Disease Models, Animal
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Crit Care Med
Year:
2003
Document type:
Article
Affiliation country:
Taiwan