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Intraoperative compliance profiles and regional lung ventilation improve with increasing positive end‐expiratory pressure
Author(s) -
Wirth S.,
Kreysing M.,
Spaeth J.,
Schumann S.
Publication year - 2016
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/aas.12767
Subject(s) - medicine , positive end expiratory pressure , pulmonary compliance , mechanical ventilation , compliance (psychology) , ventilation (architecture) , anesthesia , tidal volume , lung volumes , lung , cardiology , respiratory system , psychology , social psychology , mechanical engineering , engineering
Background Anaesthesia and mechanical ventilation can lead to impaired lung. Intraoperative positive end‐expiratory pressure ( PEEP ) should prevent intratidal recruitment/derecruitment without causing overdistension. The intratidal compliance profile indicates both unwanted phenomena. We hypothesized that a higher than usual PEEP improves the intratidal compliance and the regional lung ventilation of patients with healthy lungs. Methods After ethics approval, 30 adult patients scheduled for limb surgery were investigated at PEEP 5, 7 and 9 cm H 2 O during mechanical ventilation. We calculated the dynamic compliance of the respiratory system ( C RS ) and the intratidal volume‐dependent C RS curve. The C RS curve indicated intratidal recruitment/derecruitment and/or overdistension. Regional ventilation was measured using electrical impedance tomography. Results At PEEP 5, 7 and 9 cm H 2 O, intratidal recruitment/derecruitment was observed in 92%, 84% and 46% ( P < 0.05) of the patients respectively. Increasing PEEP was associated with recruitment in the dorsal regions of the lungs ( P < 0.001). At PEEP 9 cm H 2 O, lung overdistension was indicated in two patients. With PEEP levels up to 9 cm H 2 O, no significant effects on haemodynamic variables were found. Conclusion We conclude that in most patients, the often applied PEEP of 5 cm H 2 O is insufficient to prevent intratidal recruitment/derecruitment and that few patients show overdistension at high PEEP levels. To establish optimal pressure–volume relationships in the respiratory system, the analysis of the individual intratidal compliance profiles could be a means for individualized perioperative PEEP titration.