Gravity predominates over ventilatory pattern in the prevention of ventilator-associated pneumonia.
Crit Care Med
; 42(9): e620-7, 2014 Sep.
Article
em En
| MEDLINE
| ID: mdl-24979484
ABSTRACT
OBJECTIVE:
In the semirecumbent position, gravity-dependent dissemination of pathogens has been implicated in the pathogenesis of ventilator-associated pneumonia. We compared the preventive effects of a ventilatory strategy, aimed at decreasing pulmonary aspiration and enhancing mucus clearance versus the Trendelenburg position.DESIGN:
Prospective randomized animal study.SETTING:
Animal research facility, University of Barcelona, Spain.SUBJECTS:
Twenty-four Large White-Landrace pigs.INTERVENTIONS:
Pigs were intubated and on mechanical ventilation for 72 hours. Following surgical preparation, pigs were randomized to be positioned 1) in semirecumbent/prone position, ventilated with a duty cycle (TITTOT) of 0.33 and without positive end-expiratory pressure (control); 2) as in the control group, positive end-expiratory pressure of 5 cm H2O and TITTOT to achieve a mean expiratory-inspiratory flow bias of 10 L/min (treatment); 3) in Trendelenburg/prone position and ventilated as in the control group (Trendelenburg). Following randomization, Pseudomonas aeruginosa was instilled into the oropharynx. MEASUREMENTS AND MAINRESULTS:
Mucus clearance rate was measured through fluoroscopic tracking of tracheal markers. Microspheres were instilled into the subglottic trachea to assess pulmonary aspiration. Ventilator-associated pneumonia was confirmed by histological/microbiological studies. The mean expiratory-inspiratory flow in the treatment, control, and Trendelenburg groups were 10.7 ± 1.7, 1.8 ± 3.7 and 4.3 ± 2.8 L/min, respectively (p < 0.001). Mucus clearance rate was 11.3 ± 9.9 mm/min in the Trendelenburg group versus 0.1 ± 1.0 in the control and 0.2 ± 1.0 in the treatment groups (p = 0.002). In the control group, we recovered 1.35% ± 1.24% of the instilled microspheres per gram of tracheal secretions, whereas 0.22% ± 0.25% and 0.97% ± 1.44% were recovered in the treatment and Trendelenburg groups, respectively (p = 0.031). Ventilator-associated pneumonia developed in 66.67%, 85.71%, and 0% of the animals in the control, treatment, and Trendelenburg groups (p < 0.001).CONCLUSIONS:
The Trendelenburg position predominates over expiratory flow bias and positive end-expiratory pressure in the prevention of gravity-dependent translocation of oropharyngeal pathogens and development of ventilator-associated pneumonia. These findings further substantiate the primary role of gravity in the pathogenesis of ventilator-associated pneumonia.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Infecções por Pseudomonas
/
Respiração Artificial
/
Pneumonia Associada à Ventilação Mecânica
/
Gravitação
Tipo de estudo:
Observational_studies
/
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article