Efecto de la PEEP sobre el componente resistivo inspiratorio en pacientes con sindrome de distrés respiratorio agudo ventilados a bajo volumen corriente.

OBJECTIVE: To describe the behavior of inspiratory resistance components when positive end-expiratory pressure (PEEP) increases in patients with acute respiratory distress syndrome under a protective ventilation strategy. METHODS: In volume-controlled mode, at 6mL/kg and constant flow, end-inspiratory occlusions were performed at 0, 5 10, 15 and 20cmH2O PEEP. Peak, initial and plateau pressure values were assessed, calculating the maximum, minimum and differential resistances. The results were compared by repeated measures analysis of variance (ANOVA) with post hoc Bonferroni correction, considering p < 0.05 significant. RESULTS: The highest maximum resistance was observed at the lowest PEEP levels. The values for 10 and 15cmH2O PEEP significantly differed from those for 5 and 0cmH2O PEEP, whereas that for 20cmH2O PEEP only significantly differed from that for 0cmH2O PEEP (p < 0.05). The minimum resistance behaved similarly to the maximum resistance; the values for PEEP levels from 10cmH2O to 20cmH2O significantly differed from those for 0 and 5cmH2O PEEP (p < 0.05). Differential resistance showed the opposite variation to the maximum and minimum resistances. The only PEEP level that showed significant differences from 0 and 5cmH2O PEEP was 20cmH2O PEEP. Significant differences were also found between 15 and 5cmH2O PEEP (p < 0.05). CONCLUSIONES: Durante ventilacion protectora en pacientes com sindrome de distres respiratorio agudo, la resistencia maxima del sistema respiratorio tiene un comportamiento decreciente con la PEEP y refleja la respuesta que tiene la resistencia minima. Mientras que la resistencia diferencial mantiene su conducta creciente con los valores de PEEP.