Thoracoabdominal Asynchrony in Infants with Airflow Obstruction

Abstract

Thoracoabdominal asynchrony (TAA) has long been thought clinically useful in the assessment of airflow obstruction (AO) in infants. To test the hypothesis that the measurement of TAA is useful in the assessment of lung mechanics in infants with AO, we have used respiratory inductive plethysmography (RIP) to quantity TAA. We compared changes in TAA to changes in lung mechanics before and after aerosolized bronchodilator (BD) administration in 13 infants. Abdominal wall (AB) and rib cage (RC) motion were displayed on an X-Y recorder in a Lissajous figure. Asynchrony between RC and AB motion was quantified by comparing the width m of the Lissajous figure (difference between AB inspiratory and expiratory positions) at mid-RC excursion with the total AB excursion at its extremes (s). Phase angle phi ws computed as sin phi = m/s (or phi = 180 degrees - mu, where sin mu = m/s for phase angles greater than 90 degrees) and was taken as a measure of TAA. Lung resistance RL and elastance EL were calculated from esophageal pressure (Pes), mouth pressure, tidal volume, and tidal flow. All infants displayed TAA at baseline. After BD administration, TAA decreased in those infants in whom RL decreased. The percentage decrease in the phase angle from baseline after BD administration was significantly correlated with the decrease in peak-to-peak Pes (delta Pes) and the percentage decrease in RL and EL. We conclude that AO in infants leads to TAA through altered pleural pressure swings acting on the compliant chest wall. Changes in lung mechanics induced by bronchodilators are reflected in changes in TAA.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of different levels of positive expiratory pressure on chest wall volumes in healthy children and patients with fibrosis

“…However, PEP-induced changes on lung volumes are not fully established due to muscular limitations and consequent respiratory muscles asynchronous activity that may be present in children with CF 11 . Besides lung disorders, children with CF frequently show paradoxical or asynchronous motion between chest wall and abdomen during breathing [12][13][14] . This alteration is related to disease severity, increased risk of respiratory failure, and poor prognosis in patients with obstructive disease 15,16 .…”

Prone position and reduced thoracoabdominal asynchrony in preterm newborns

“…Nos estudos em que foram avaliados parâmetros respiratórios, analisou-se um número exíguo de ciclos respiratórios 20 , ou um tempo reduzido de registro foi relatado [12][13][14] , ou ainda há estudos que não apresentaram desenhos metodológicos detalhados 21,22 . Assim, questiona-se ainda os reais benefícios das posições prona e supina em recém-nascidos a termo e pré-termo 8,15,23 .…”

Proportional Assist Ventilation Decreases Thoracoabdominal Asynchrony and Chest Wall Distortion in Preterm Infants

“…External loads of the respiratory system as well as internal loads from changes in pulmonary mechanics secondary to a disease process increase TAA in neonates and infants (2,7,34). The removal of the load has been shown to improve synchrony and distortion (2,34).…”

“…The removal of the load has been shown to improve synchrony and distortion (2,34). PAV provided unloading of the respiratory system by removal of the resistive load of the ETT and the disease-related internal elastic load of the lungs.…”

“…Abbreviations ABD, area under the curve of the abdominal band signal during inspiration BW, birth weight CPAP, continuous positive airway pressure CWD, chest wall distortion ETT, endotracheal tube PAV, proportional assist ventilation Paw, airway pressure change Pes, esophageal pressure change RC, area under the curve of the rib cage band signal during inspiration TAA, thoracoabdominal asynchrony TCD ratio, total compartmental displacement ratio Vt, tidal volume TAA, in which the rib cage and abdomen move out of phase due to inward CWD, are commonly seen in spontaneously breathing preterm infants. TAA and CWD are more pronounced in the presence of decreased lung compliance or increased airway resistance but can also be seen in preterm infants without lung disease or in term infants during REM sleep (1)(2)(3)(4). The phenomenon is caused by mainly two factors: the negativity of the pleural pressure generated during inspiration and the compliance of the chest wall (5-7).…”