Single and sequential voluntary cough compromised in children with acquired spinal cord injury

Abstract

ObjectiveCough is a protective mechanism to keep the airways clear form any foreign material inhaled or secreted from the lung. Spinal cord injury (SCI) at cervical and thoracic levels leads to paralysis or weakness of respiratory muscles. The workload of breathing increases, which results in low lung volumes and weak cough. There is a linear relationship between lung volume and cough expired volume. Ineffective or weak cough causes difficulty in clearing secretions, which in turn causes mucus retention and increases risk for atelectasis and pneumonia. Cough efficacy is an important factor in determining the risk of aspiration. A typical cough is a three‐phase expulsive motor task: inspiratory, compressive, and expiratory airflow phases against a closed glottis. The effectiveness of a cough can be evaluated non‐invasively by measuring peak inspiratory and expiratory flows generated during cough. The objective of this study is to investigate and quantify single and sequential voluntary cough in children with SCI compared to typically developing (TD) children. We hypothesized that children with acquired SCI would have significantly reduced lung volumes and cough airflow parameters compared to age matched TD children.MethodsEight TD children (age 8±3 years) with no history of respiratory or cardiovascular dysfunction, were recruited from the local community and six children with acquired SCI (age 9±4 years) were recruited from Frazier Rehabilitation Institute, Louisville, KY. The Institutional Review Board (IRB) at the University of Louisville approved this study (IRB protocol #15.0585). Informed consent and assent were signed by legal guardians of children and by children above 7 years of age, respectively. Outcome measures included spirometry (lung volumes) and cough parameters.ResultsMean values of forced vital capacity (FVC) and forced volume in one second (FEV1) in TD children were greater than in children with SCI. For single cough, TD children demonstrated greater expiratory phase peak flow (EPPF) with longer compression phase duration (CPD) than children with SCI. For sequential cough, EPPF for each cough epoch was greater in TD children than in children with SCI. However, the CPD values for all three cough epochs were longer in children with SCI than in TD children.ConclusionThis is the first study to report preliminary data on objective evaluation and quantification of cough function in children with acquired SCI. We reported reduced lung volumes and peak cough flows (EPPF) in children with acquired SCI. This indicates the deficits in cough function and potential high risk for respiratory complications. Interventions that target respiratory capacity directly or indirectly may have the potential to improve cough function in children with acquired SCI.Support or Funding InformationKosair Charities and Todd Crawfird Foundation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.