Regional lung volume changes in children with acute respiratory distress syndrome during a derecruitment maneuver

• Published in: Critical care medicine Vol. 35; no. 8; pp. 1972 - 1978
• Main Authors: Wolf, Gerhard K, Grychtol, Bartlomiej, Frerichs, Inez, van Genderingen, Huibert R, Zurakowski, David, Thompson, John E, Arnold, John H
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD by the Society of Critical Care Medicine and Lippincott Williams & Wilkins 01-08-2007; Lippincott
• Subjects: Adolescent; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Child; Child, Preschool; Electric Impedance; Emergency and intensive respiratory care; Humans; Injuries of the thorax. Foreign bodies. Diseases due to physical agents; Intensive care medicine; Lung Volume Measurements; Medical sciences; Monitoring, Physiologic - methods; Positive-Pressure Respiration; Prospective Studies; Pulmonary Alveoli - physiopathology; Respiratory Distress Syndrome, Adult - diagnosis; Respiratory Distress Syndrome, Adult - therapy; Suction; Tomography - methods; Traumas. Diseases due to physical agents; Human; Intensive care; Respiratory disease; gravitational axis; Lung volume; closed suctioning; electrical impedance tomography; relative impedance change; Tomography; Respiratory distress; Child; Resuscitation; Electrical impedance
• ISSN: 0090-3493; 1530-0293
• DOI: 10.1097/01.CCM.0000275390.71601.83

OBJECTIVE:Regional differences in lung volume have been described in adults with acute respiratory distress syndrome, but it remains unclear to what extent they occur in children. To quantify regional alveolar collapse that occurred during mechanical ventilation during a standardized suctioning maneuver, we evaluated regional and global relative impedance changes (relative ΔZ) in children with acute respiratory distress syndrome using electrical impedance tomography.
DESIGN:Prospective observational trial.
SETTING:A 30-bed pediatric intensive care unit.
PATIENTS:Six children with acute respiratory distress syndrome.
INTERVENTIONS:Standardized suctioning maneuver.
MEASUREMENTS AND MAIN RESULTS:By comparing layers from nondependent (layers 1 and 2) to dependent lung areas (layers 3 and 4), it was demonstrated that the middle layers (2 and 3) had the greatest ventilation-induced change in relative ΔZ; layer 4 showed the least ventilation-induced change in relative ΔZ. During suctioning, layers 1, 2, and 3 showed a negative change in relative ΔZ, whereas layer 4 showed no significant change in relative ΔZ. The derecruitment-induced change in relative ΔZ representing the lung-volume loss was −9.8 (−3.0 mL/kg) during the first suctioning maneuver, −16.1 (−5.4 mL/kg) during the second, and −21.7 (−7.4 mL/kg) during the third. The ventilation-induced change in relative ΔZ during mechanical ventilation remained unchanged after suctioning (mean change in relative ΔZ before vs. after suctioning, 40.1 ± 9.1 vs. 41.4 ± 10.8; p = .30). Dynamic compliance was 11.8 ± 6.1 mL·cm H2O before and 11.8 ± 6.9 mL·cm H2O after the suctioning sequence (p = .90).
CONCLUSIONS:Considerable regional heterogeneity was present during ventilation and a derecruitment maneuver. Significantly lower change in relative ΔZ in the most dependent lung regions suggests alveolar collapse during ventilation before suctioning.