Impact of Low versus High PEEP Strategies on Respiratory Mechanics and Outcomes in Mechanically Ventilated Intensive Care Patients: A Prospective Observational Study

Abstract

Introduction: The optimal level of positive end-expiratory pressure (PEEP) in mechanically ventilated patients with acute respiratory failure remains debated. High PEEP may enhance alveolar recruitment and oxygenation but increase plateau and driving pressures, risking ventilator-induced lung injury (VILI). Conversely, low PEEP may reduce overdistension but promote alveolar collapse and hypoxemia. Understanding how PEEP strategies affect respiratory mechanics and outcomes is crucial for individualized ventilator management.
Methods: A prospective observational study was conducted in the intensive care unit of Hospital Clínico Quirúrgico Miguel Enríquez, Havana, Cuba, between January 2021 and January 2022. Thirty adult patients requiring invasive mechanical ventilation for ≥48 hours were allocated to a low PEEP group (8–12 cmH₂O, n = 15) or a high PEEP group (15–18 cmH₂O, n = 15). Data collected included respiratory mechanics (PaO₂/FiO₂, static compliance, plateau and driving pressures), hemodynamics (mean arterial pressure, heart rate, vasopressor use), and clinical outcomes (duration of mechanical ventilation, ICU stay, 28-day mortality, barotrauma, ventilator-associated pneumonia).
Results: Among 30 patients, high PEEP improved oxygenation compared with low PEEP (PaO₂/FiO₂ 218 ± 10 vs 170 ± 38 mmHg; p < 0.01). Plateau (28 ± 4 vs 21 ± 3 cmH₂O; p < 0.001) and driving pressures (15 ± 3 vs 11 ± 2 cmH₂O; p < 0.001) were higher in the high PEEP group, whereas static compliance was similar (36 ± 7 vs 38 ± 6 mL/cmH₂O; p = 0.34). Hemodynamics and major outcomes were comparable. Barotrauma occurred in two patients in the high PEEP group and in none in the low PEEP group.
Conclusion: High PEEP improves oxygenation but increases plateau and driving pressures, highlighting the need for individualized titration to minimize VILI risk. Both low and high PEEP strategies were well tolerated, with similar hemodynamic stability and short-term mortality, supporting personalized ventilator management in ICU patients.