Cardiopulmonary analysis and a comparative study to predict maximum oxygen consumption in non-ambulatory children with myelomeningocele using direct and indirect tests.

Children with myelomeningocele (MMC) present primary abnormalities in neural tube with nerve tissue extrusion. Secondary alterations, such as paraplegia, can compromise the cardiopulmonary performance and cardiac autonomic function, mainly in individuals who are exclusively dependent on a wheelchair. Although the scientific literature has extensively studied the clinical manifestations of MMC and their different neural lesion levels, poor attention has been addressed to cardiopulmonary dysfunction. Evaluation of cardiac autonomic function and cardiopulmonary capacity using maximum oxygen uptake (VO2max) has been used to predict risk factors related to health, but this gold standard technique requires specificities that limit its widespread use. Objectives: To analyze the difference cardiopulmonary capacity of children and adolescents with myelomeningocele unable to walk and his or her matched control by detecting data that predispose to cardiovascular risks, and using an indirect test in order to estimate the VO2max in children with MMC. Methods: Twenty two (n = 11) children and adolescents participated of this cross-sectional study, both sexes, aged 8 15 years, separated into two groups: Group Myelomeningocele (GM), with 11 children and adolescents with myelomeningocele unable to walk (wheelchair users); and Control Group (CG), with 11 healthy children and adolescents matched for sex, age, weight and/or height. The data obtained were: Anthropometric data; body composition by bioelectrical impedance analysis; index maturation classification by Taner; level of physical activity by IPAQ; isometric muscle strength of shoulder abductors, elbow flexors and extensors using Handheld dynamometer, and grip muscle strength using bulb dynamometer; Spontaneous baroreflex sensitivity (SBS) and heart rate and blood pressure variability (HRV and BPV) evaluation; cardiopulmonary exercise testing on a cycle ergometer of upper limb (direct test = DT); and indirect test following the method proposed by Franklin et al., (1990) to estimate VO2max. Results: Anthropometry data and muscle strength did not present significant difference between analyzed groups (p > 0.05). GM presented approximately 6kg increased fat mass than CG (p 0.05). By cardiopulmonary test, GM presented reduced VO2peak compared to GC, indicating a significant difference between groups (p 0.05). The VO2peak have positive correlation with anthropometric data and fat free mass and muscle strength. The VO2max in DT varied between 2456% higher than those on the IT, but rest and maximum HR mean value comparisons showed no statistical difference between the tests. Considering cardiac autonomic function, no difference was observed to spectral parameters of HRV, but low frequency of BPV and the SBS were significantly lower in GM (p < 0.05). Conclusion: Children with MMC present reduced cardiopulmonary capacity than their healthy peers and reduced spontaneous baroreflex sensitivity and sympathetic control on BPV, indicating some predisposition to risk of cardiovascular event. And yet, VO2max values estimated by the chosen IT underestimated the DT values and were not applicable to this population; however, they may represent a potential model to test maximal exercise and obtain maximal HR values, which need to be explored further in this population. (AU)