Measurement of lung volumes and pulmonary mechanics during weaning of newborn infants with intractable respiratory failure from extracorporeal membrane oxygenation

Abstract

Newborn infants with intractable respiratory failure who require extracorporeal membrane oxygenation (ECMO) experience diffuse pulmonary atelectasis shortly after initiation of ECMO. Atelectasis is likely due to the primary lung injury and the reduction of applied inspiratory ventilator pressure when the respirator settings are changed to the "rest settings." These pathophysiologic changes result in a decrease in lung compliance and lung volumes. We hypothesized that improving lung functions observed during ECMO and indicated by an increase in lung volumes will predict successful weaning from ECMO. Sixteen infants (mean +/- SEM: gestational age, 40.3 +/- 0.3 weeks; birth weight, 3.5 +/- 0.1 kg) with meconium aspiration syndrome (n = 13), sepsis (n = 2), and persistent pulmonary hypertension (n = 1) were studied. We measured passive respiratory system mechanics and lung volumes initially during full ECMO support (115 +/- 18 h on ECMO, Study I), and then within 24 h prior to weaning from ECMO (Study II). Respiratory system compliance (Crs), respiratory system resistance (Rrs), functional residual capacity (FRC), and tidal volume (VT) were measured. Prior to Study I lung volumes were too small to be detected. Crs increased between Study I and Study II (0.41 +/- 0.05 to 0.63 +/- 0.05 mL/cmH2O/kg, P < 0.05), and VT increased between Study I and Study II (5.6 +/- 0.6 to 10.4 +/- 0.8 mL/kg, P = 0.0005). FRC increased from 3.6 +/- 1.0 to 7.9 +/- 0.9 mL/kg (P = 0.0001). There was no change in Rrs (88 +/- 8 to 89 +/- 6 cm H2O/L/s, P = 0.9). The combination of Crs > 0.5 mL/cmH2O/kg and FRC > 5 mL/kg was a better predictor (P = 0.0002) of readiness to wean from ECMO than either Crs (> 0.5 mL/cmH2O/kg, P = 0.057) or FRC (> 5 mL/kg, P = 0.007) alone. The combination of FRC and Crs had a sensitivity of 73.3% and specificity of 100% for successful decannulation. We conclude that repeated measurements of FRC and Crs can assess lung recovery and may assist in establishing criteria for successful weaning from ECMO.

Surfactant application during extracorporeal membrane oxygenation improves lung volume and pulmonary mechanics in children with respiratory failure

“…Reiterer et al . [ 16 ] and previous investigators [ 5 , 17 - 20 ] have described improvement of compliance during ECMO and especially in combination with surfactant treatment. They mentioned that Crs, functional residual capacity and VT improved significantly, and each of these parameters correlated with successful weaning from ECMO.…”

“…They mentioned that Crs, functional residual capacity and VT improved significantly, and each of these parameters correlated with successful weaning from ECMO. The combination of functional residual capacity and Crs was the best predictor for successful weaning from ECMO [ 17 ]. The decision of when to stop ECMO is based upon the return of adequate pulmonary and cardiac function to support vital organs and permit subsequent recovery [ 21 ].…”

Are tidal volume measurements in neonatal pressure‐controlled ventilation accurate?

“…Clinical applications are many, including measuring respiratory parameters, guiding clinical management to minimize volume trauma, and applying different ventilatory strategies according to pulmonary function tests. [1][2][3][4][5][6][7][8] Additionally, PMM have been helpful in evaluating the usefulness of medical therapies such as diuretics, bronchodilators, and surfactant. 1,9 Information from PMM may also be used to compare babies within and between different centers, and to assess trends in clinical parameters.…”

Static lung compliance suggests successful ECMO decannulation in neonates

“…There are several previous reports discussing the indicators showing improvement of lung mechanics during ECMO and the timing of weaning from ECMO. Kugelman et al 3 . reported that the combination of C st >0.5 mL/cmH 2 O/kg and FRC >5 mL/kg was a good predictor for weaning from ECMO, which had a sensitivity of 73.3% and specificity of 100% for successful decannulation.…”