Pressure Characteristics of Mechanical Ventilation and Incidence of Pneumothorax Before and After the Implementation of Protective Lung Strategies in the Management of Pediatric Patients With Severe ARDS

To compare pressure characteristics of mechanical ventilation and their impact on pediatric patients with severe ARDS in the pre-protective lung strategy (PLS) and post-PLS eras.Medical records of 33 patients admitted to our pediatric ICU with ARDS from 1992 through 1994 (pre-PLS) and 52 patients with ARDS admitted from 2000 through 2003 (post-PLS) were retrospectively reviewed.Patient age and gender distribution were identical in both eras. Fifty-five percent of the patients in the pre-PLS era had pneumothorax, compared to 17% in the post-PLS era (p < 0.05). Overall mortality rates for patients in the pre-PLS and post-PLS eras were 42% and 25%, respectively (p = 0.09; not significant). Mean duration of exposure to peak inspiratory pressure (PIP) values > 40 cm H2O was significantly longer in the pre-PLS era than in the post-PLS era. Pre-PLS patients with pneumothorax received mean maximum PIP of 72 +/- 17 cm H2O, mean maximum positive end-expiratory pressure (PEEP) of 20 +/- 5 cm H2O, and maximum mean airway pressure (MAP) of 46 +/- 8 cm H2O, while patients in the post-PLS era required mean maximum PIP of 42 +/- 2 cm H2O, mean maximum PEEP of 14 +/- 2 cm H2O, and maximum MAP of 30 +/- 6 cm H2O, respectively (p < 0.05 for all pressure parameters). There were no significant differences in mechanical ventilation pressure characteristics among patients who did not have pneumothorax during their course of management in both eras.A significantly more aggressive use of ventilator pressure characteristics distinguished the pre-PLS era from the post-PLS era, and was found to be associated with a markedly higher incidence of pneumothorax. Outcome in both eras did not differ significantly, presumably due to insufficient statistical power.