• Marco Antonio León-Gutiérrez, Jorge Alberto Castañón-González, Eugenio E Lázaro-Castillo, Jorge Alfredo Pech-Quijano, and Octavio Iván Abraján-Hernández.
• Facultad de Medicina, Universidad Nacional Autónoma de México, and Unidad de Cuidados Intensivos y Medicina Crítica, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, IMSS, Huixquilucan, Estado de México, México.
• Cir Cir. 2006 Jul 1; 74 (4): 243-8.

BackgroundPositive end-expiratory pressure increases mean airway pressure (Paw) in patients with mechanical ventilation. We undertook this study to compare mean airway pressure (Paw) generated with static PEEP (sPEEP) vs. dynamic PEEP (dPEEP) at the same level of total PEEP (tPEEP) in the same patient with pressure-controlled mechanical ventilation (PC).MethodsWe conducted a prospective clinical trial at the Intensive Care Unit of a university-affiliated hospital. Consecutive patients in PC with SaO2>90%; FiO2<50%; sPEEP of 4 cm H2O and inspiration-expiration ratio (I:E ratio) 1:2 were included in the study. After a basal period of time of 15 min, Paw was registered (phase one of the study protocol). In phase 2 with the ventilator settings constant, only the I:E ratio was switched to 2:1 to generate dPEEP, and after 15 min Paw and total PEEP (tPEEP) were registered (tPEEP=sPEEP+dPEEP). In phase 3, the I:E ratio was switched back to 1:2 substituting the dPEEP generated in the second phase of the study by sPEEP to maintain the same level of tPEEP of phase 2. After 15 min, Paw was again registered. Friedman and Wilcoxon's test were used, p value<0.05 was considered statistically significant.ResultsThirty eight patients were admitted to the study protocol, tPEEP was 4, 8 and 8 cm H2O and median of the Paw 8.7, 13.8, and 11.4 cm H2O, respectively, with a p value<0.05 in the first, second and third phases of the study.ConclusionsDuring pressure control ventilation, mean airway pressure is affected by the level of total PEEP and its composition. Paw is higher when dynamic PEEP participates in the composition of total PEEP.

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