Breathing Pattern and Ventilatory Control in Chronic Tetraplegia

Impact of neurological level and spinal curvature on pulmonary function in adults with spina bifida

PURPOSE

To describe pulmonary function and determine the impact of neurological level, scoliosis, and obesity on pulmonary function in people with spina bifida (SB).

METHODS

Participants with SB (N= 29) (15 females; age, 30 ± 12 years) completed spirometry and body plethysmographic lung volume testing. Univariate and multivariate regression analyses were used to describe the factors associated with pulmonary function in people with SB.

RESULTS

Distribution of category of impairment in pulmonary function was: 55% (n= 16) restricted, 6.9% (n= 2) spirometric restricted, 1 combined obstructed and restricted, and 35.5% (n= 10) normal. In univariate analyses, neurological level was negatively associated with pulmonary function parameters, i.e., forced vital capacity (FVC) (p= 0.005), forced expiratory volume in 1 second (FEV1) (p= 0.008), total lung capacity (TLC) (p= 0.001), and degree of scoliosis were inversely associated with FVC (p= 0.005), FEV1 (p= 0.003), and TLC (p= 0.004). In multivariate models, level of lesion and degree of scoliosis independently contributed to the degree of lung function impairment. Restrictive pulmonary function was observed in 9/10 (90%) of those with thoracic neurological levels and was associated with decreased inspiratory capacity (IC) and expiratory reserve volume (ERV). Lumbar level lesions were associated with either normal lung function or an isolated reduction in FVC due to reduction in only ERV and preserved TLC representing spirometric restriction.

CONCLUSIONS

High prevalence of restrictive pulmonary physiology is present in people with SB, with more rostral neurological levels and greater degree of scoliosis associated with a higher degree of pulmonary function impairment.

A chronic care model for spina bifida transition

Providing comprehensive transition care for adolescents and young adults with spina bifida (AYASB) requires a structured approach to addressing chronic condition management, self-management, care coordination, and health care navigation that is adaptable to the various levels of cognitive ability, physical function, and family/community environments within the population. This commentary (1) highlights AYASB transition program needs identified in the literature and within a local community, (2) analyzes advantages and limitations of published AYASB transition care models in addressing these needs, (3) demonstrates how a spina bifida (SB) transition clinic used the Chronic Care Model (CCM) to develop a comprehensive AYASB transition program, and (4) examines the potential feasibility in adapting this model to other SB clinics. A SB-specific transition clinic based on the CCM model facilitates the complex chronic care management and transition planning for AYASB. Further study is needed to evaluate health care outcomes using the CCM for SB transition.

Abdominal functional electrical stimulation to improve respiratory function after spinal cord injury: a systematic review and meta-analysis

OBJECTIVES

Abdominal functional electrical stimulation (abdominal FES) is the application of a train of electrical pulses to the abdominal muscles, causing them to contract. Abdominal FES has been used as a neuroprosthesis to acutely augment respiratory function and as a rehabilitation tool to achieve a chronic increase in respiratory function after abdominal FES training, primarily focusing on patients with spinal cord injury (SCI). This study aimed to review the evidence surrounding the use of abdominal FES to improve respiratory function in both an acute and chronic manner after SCI.

SETTINGS

A systematic search was performed on PubMed, with studies included if they applied abdominal FES to improve respiratory function in patients with SCI.

METHODS

Fourteen studies met the inclusion criteria (10 acute and 4 chronic). Low participant numbers and heterogeneity across studies reduced the power of the meta-analysis. Despite this, abdominal FES was found to cause a significant acute improvement in cough peak flow, whereas forced exhaled volume in 1 s approached significance. A significant chronic increase in unassisted vital capacity, forced vital capacity and peak expiratory flow was found after abdominal FES training compared with baseline.

CONCLUSIONS

This systematic review suggests that abdominal FES is an effective technique for improving respiratory function in both an acute and chronic manner after SCI. However, further randomised controlled trials, with larger participant numbers and standardised protocols, are needed to fully establish the clinical efficacy of this technique.

Breath stacking in children with neuromuscular disorders

Respiratory muscle weakness in neuromuscular disorders (NMD) can lead to shallow breathing and respiratory insufficiency over time. Children with NMD often cannot perform maneuvers to recruit lung volume. In adults, breath stacking with a mask and one-way valve can achieve significantly increased lung volumes. To evaluate involuntary breath stacking (IBS) in NMD, we studied 23 children of whom 15 were cognitively aware and able to communicate verbally. For IBS, a one-way valve and pneumotachograph were attached to a face mask. Tidal volumes (Vt) and minute ventilation (VE ) were calculated from airflow over 30 sec before and after 15 sec of expiratory valve closure. Six cooperative male subjects with Duchenne muscular dystrophy (DMD) participated in a subsequent comparison of IBS with voluntary breath stacking (VBS) and supported breath stacking (SBS). The average Vt in those studied with IBS was 277 ml (range 29-598 ml). The average increase in volume by stacking was 599 ml (range -140 to 2,916 ml) above Vt . The average number of stacked breaths was 4.5 (range 0-17). VE increased on average by 18% after stacking (P < 0.05, paired t-test). Oxygen saturation did not change after stacking. Four of the 23 children did not breath stack. Compared to IBS, VBS achieved similar volumes in the six subjects with DMD but SBS was more successful in those with greatest muscle weakness. IBS may achieve breath volumes of approximately three times Vt and may be particularly useful in non-cooperative subjects with milder degrees of respiratory muscle weakness.