Regional lung derecruitment after endotracheal suction during volume- or pressure-controlled ventilation: a study using electric impedance tomography
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To assess lung volume and compliance changes during open- and closed-system suctioning using electric impedance tomography (EIT) during volume- or pressure-controlled ventilation.
Design and setting
Experimental study in a university research laboratory.
Nine bronchoalveolar saline-lavaged pigs.
Open and closed suctioning using a 14-F catheter in volume- or pressure-controlled ventilation at tidal volume 10 ml/kg, respiratory rate 20 breaths/min, and positive end-expiratory pressure 10 cmH2O.
Measurements and results
Lung volume was monitored by EIT and a modified N2 washout/-in technique. Airway pressure was measured via a pressure line in the endotracheal tube. In four ventral-to-dorsal regions of interest regional ventilation and compliance were calculated at baseline and 30 s and 1, 2, and 10 min after suctioning. Blood gases were followed. At disconnection functional residual capacity (FRC) decreased by 58 ± 24% of baseline and by a further 22 ± 10% during open suctioning. Arterial oxygen tension decreased to 59 ± 14% of baseline value 1 min after open suctioning. Regional compliance deteriorated most in the dorsal parts of the lung. Restitution of lung volume and compliance was significantly slower during pressure-controlled than volume-controlled ventilation.
EIT can be used to monitor rapid lung volume changes. The two dorsal regions of the lavaged lungs are most affected by disconnection and suctioning with marked decreases in compliance. Volume-controlled ventilation can be used to rapidly restitute lung aeration and oxygenation after lung collapse induced by open suctioning.
KeywordsAcute Lung Injury Electrical impedance tomography Functional residual capacity Monitoring Suctioning Lung recruitment
- 3.Bernard GR, Artigas A, Brigham KL, Carlet J, Falke K, Hudson L, Lamy M, LeGall JR, Morris A, Spragg R (1994) Report of the American-European Consensus Conference on ARDS: definitions, mechanisms, relevant outcomes and clinical trial coordination. The Consensus Committee. Intensive Care Med 20:225–232PubMedCrossRefGoogle Scholar
- 7.Craig CK, Benson MS, Pierson DJ (1984) Prevention of arterial oxygen desaturation during closed-airway endotracheal suction: effect of ventilator mode. Respir Care 29:1013–1018Google Scholar
- 21.Victorino JA, Borges JB, Okamoto VN, Matos GF, Tucci MR, Caramez MP, Tanaka H, Sipmann FS, Santos DC, Barbas CS, Carvalho CR, Amato MB (2004) Imbalances in regional lung ventilation: a validation study on electrical impedance tomography. Am J Respir Crit Care Med 169:791–800PubMedCrossRefGoogle Scholar
- 23.United States National Research Council (1996) Commission on Life Sciences. Institute of Laboratory Animal Resources Guide for the care and use of laboratory animals. National Academy PressGoogle Scholar
- 24.Odenstedt H, Lindgren S, Olegard C, Erlandsson K, Lethvall S, Aneman A, Stenqvist O, Lundin S (2005) Slow moderate pressure recruitment maneuver minimizes negative circulatory and lung mechanic side effects: evaluation of recruitment maneuvers using electric impedance tomography. Intensive Care Med 31:1706–1714PubMedCrossRefGoogle Scholar
- 30.Olegard C, Sondergaard S, Houltz E, Lundin S, Stenqvist O (2005) Estimation of functional residual capacity at the bedside using standard monitoring equipment: a modified nitrogen washout/washin technique requiring a small change of the inspired oxygen fraction. Anesth Analg 101:206–212, table of contentsPubMedCrossRefGoogle Scholar