RESUMO
ObjectiveTo determine optimal positive end expiratory pressure (PEEP) in mechanical ventilation in children with severe asthmatoid disease based on the quasistatic pressure-volume (P-V) curve.MethodsA serf-control study was done on 23 children with severe asthmatoid disease in the pediatric intensive care unit( PICU ).Quasistatic lung P-V curve of these patients was analyzed and the lower inflection point (LIP) from P-V curve was determined.Three different PEEP (0 cm H2O,LIP,LIP+2 cm H2O,1 mm H2O =0.098 kPa) were given to the patients.The effects of PEEP at different levels on gas exchange,hemodynamic and airway pressure were observed.ResultsThe quasistatic LIP were (2.70 ±2.00)cm H2O.When PEEP was increased to the level of LIP + 2 cm H2O,PaO2 / FiO2 and lung compliance improved significantly (P ＜ 0.01 ) and dynamic lung compliance was the highest,peak inspiratory pressure was (22.30 ± 3.00) cm H2O and mean airway pressure was( 14.11 ± 1.01 ) cm H2O,without obvious adverse effects on mean arterial blood pressure and heart rate.There was no difference in PaCO2,when compared PEEP =0 cmH2O to PEEP =LIP + 2 cmH2O.ConclusionThe application of PEEP is safe.LIP + 2 cm H2O from quasistatic P-V curve could be set as the optimal PEEP under which mechanical ventilation has the best efficacy and do not aggravate CO2 retention and abnormality of hemodynamics in children with severe asthmatoid disease.