Difference in lung distribution of ventilation between positive end-expiratory pressure 5 cmH2O and 10 cmH2O in postoperative patients using electrical impedance tomography assessment

Background. Atelectasis is one of the most common perioperative respiratory complications seen in the first 24hours postoperatively and it can actually persist for several days afterwards. Application of Positive End-ExpiratoryPressure (PEEP) can prevent postoperative alveolar collapse which is behind atelectasis. The study compares theinfluence of PEEP either 5 cmH2O (PEEP-5) or 10 cmH2O (PEEP-10) on the distribution of ventilation in postoperative patients using Electrical Impedance Tomography (EIT). Material and methods. A single-blind randomized clinical trial was conducted in the Intensive Care Unit of University Hospital upon 35 patients. The subjectswere randomized into two groups: either postoperative mechanical ventilation with PEEP-5 or with PEEP-10. Thepatients were monitored with EIT PulmoVista 500® with values of the following parameters being taken: globalTidal Impedance Variation (gTIV), regional Tidal Impedance Variation (rTIV) for both anterior and posteriorparts of the lungs, global End-Expiratory Lung Impedance (gEELI), regional End-Expiratory Lung Impedance(rEELI) for both anterior and posterior parts of the lungs, Regional Dynamic Compliance Change (RC) for bothanterior and posterior parts of the lungs. Then the calculated parameters and their relationship were analyzed forPEEP-5 and PEEP-10 group over time points taken (0-20-40-60 min) and lung regions (anterior/posterior). Results. Analysis of rTIV and gTIV values in PEEP-5 and PEEP-10 group have shown statistically significant differencein measurements taken at the 20th minute (p<0.05) of the study. The analysis of gEELI and rEELI values taken atboth anterior and posterior parts of the lungs in PEEP-5 and PEEP-10 group have shown statistically significantdifference in every measurement taken (p < 0.05). ΔRC difference values (ΔRC) at both anterior and posteriorparts of the lungs between PEEP-5 and PEEP-10 group were statistically significantly different (p < 0.05) in everymeasurement taken. There were no differences between two groups in terms of PaO2/FiO2 ratio, the length of intubation and the duration of hospitalization. Conclusions. Despite statistically significant differences in pulmonaryparameters (TIV, EELI, RC) measured between PEEP-5 and PEEP-10 groups short term patients’ outcome definedby PaO2/FiO2 ratio, the length of intubation and the duration of hospitalization did not differ between both groups.Anestezjologia i Ratownictwo 2018; 12: 5-17.