Respiratory muscle force and lung volume changes in a population of children with sickle cell disease

Abstract

Sickle cell disease (SCD) is a disorder known to impact the respiratory system. We sought to identify respiratory muscle force and lung volume relationships in a paediatric SCD population. Thirty-four SCD-SS subjects underwent pulmonary function testing. Height, weight, age, and gender-adjusted percent predicted maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) values were compared to spirometry and lung volumes. Statistical analyses were performed using Pearson’s correlation coefficient and paired two-tailed t-test. The mean ±standard deviation (SD) MIP and MEP was 69.6 ±31.6 cm H2O and 66.9 ±22.9 cm H2O, respectively, and mean ±SD percent predicted MIP (101.3 ±45.9) exceeded MEP (72.1 ±26.0) (p = 0.002). MIP correlated with forced vital capacity (FVC; r = 0.51, p = 0.001) and TLC (r = 0.54, p < 0.0001). MEP also correlated with FVC (r = 0.43, p = 0.011) and total lung capacity (TLC; r = 0.42, p = 0.013). Pearson’s correlation coefficient testing yielded relationships between MIP and MEP (r = 0.64, p < 0.0001). SCD-SS patients showed correlations between respiratory muscle force and lung volume, and reduced percent predicted expiratory muscle force compared to inspiratory muscle force. Respiratory muscle strength may affect lung volumes in these patients, and expiratory muscles may be more susceptible than the diaphragm to SCD-induced vaso-occlusive damage.

Cognitive and behavior deficits in sickle cell mice are associated with profound neuropathologic changes in hippocampus and cerebellum

“…Our findings of reduced voluntary exercise capacity in two strains of SCD mice are in concert with several studies showing that children and adults with SCD have reduced exercise capacity and decreased muscle force(Callahan et al, 2002; Chaudry et al, 2013; Dougherty et al, 2011; Ong et al, 2013; van Beers et al, 2014). In SCD, mechanisms believed to underlie these limitations include pulmonary and peripheral vascular diseases and anemia(Callahan et al, 2002; Chaudry et al, 2013; Dougherty et al, 2011; Ong et al, 2013; van Beers et al, 2014).…”

“…In SCD, mechanisms believed to underlie these limitations include pulmonary and peripheral vascular diseases and anemia(Callahan et al, 2002; Chaudry et al, 2013; Dougherty et al, 2011; Ong et al, 2013; van Beers et al, 2014). We posit that yet another possible contributing factor is muscle hyperalgesia, which in rodents can be associated with decreased muscle strength and reduced running distances on the voluntary wheel(Cobos et al, 2012; Grace et al, 2014).…”

Pattern of Lung Function Is Not Associated with Prior or Future Morbidity in Children with Sickle Cell Anemia

“…The recent findings by Ong et al (36) of decreases in respiratory muscle force and the resultant decreases in maximal expiratory pressure in children with SCD could provide an explanation for the findings of non-specific patterns. Muscle strength was not measured in our cohort, however the finding of slow VC not being higher than FVC does not support decreased muscle strength as a primary cause of non-specific pattern in our population.…”

Lung function and six-minute walk test performance in individuals with sickle cell disease

“…Prior studies have assessed lung function 8 - 11 and functional capacity 12 - 14 in adults with SCD. However, we are unaware of any studies in the published literature that concomitantly assess pulmonary function, functional capacity and muscle strength to identify potential relationships between these variables and to examine possible damage caused by SCD.…”