A spinal cord injury (SCI) has a profound and devastating impact on not only the person involved, but those close to them. Most people who have suffered a SCI experience a multitude of bodily dysfunctions that need to be managed and optimized in order to minimize complications. Common complications in those with a tetraplegic injury include low blood pressure (BP), decreased breathing capacity and reduced respiratory support for voice. An abdominal binder (AB) has been recommended by numerous textbooks and several authors as a device used to assist with the above complications. However, the evidence to support this recommendation is lacking, and current practices have seen the AB discarded after the first few weeks of rehabilitation.
The research project consisted of two studies. The first was a systematic literature review and meta-analysis and the second was a randomized cross over within subject trial to determine the effect of the AB. The aims of the studies were to: 1. Determine systematically the evidence for AB use in SCI in terms of its effects on respiratory function, haemodynamics and voice parameters; 2. Investigate the impact of an AB used in sitting on respiratory volumes, respiratory muscle pressure generation, respiratory support for voice and BP parameters at 3 different time points within the first year after a motor complete tetraplegia.
The systematic review of the literature highlighted that there are two different types of ABs available, either rigid or elastic, and that the effect of both types is similar. The review found that no studies have investigated the effect of a clinically available AB alone on BP, particularly the incidence of orthostatic hypotension (OH) for which an AB is typically prescribed, or on voice. All studies except one reported the respiratory effects of an AB at a single point in time only. The meta-analysis found that the AB significantly improved vital capacity (VC) by a mean 0.32 litres (95%CI 0.09, 0.55) but reduced functional residual capacity (FRC) by a mean 0.41 litres (95%CI 0.14, 0.67).
The second study, a randomized crossover trial, was designed based on the evidence obtained from the systematic review and meta-analysis. The trial measured forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), mean arterial pressure (MAP) and respiratory support for voice by way of maximum sustained phonation (MSP) and voice loudness (VL). Of particular clinical interest was determining patient compliance with AB use and factors which influence this.
Overall, an AB resulted in a significant improvement in FVC [weighted mean difference 0.34litres (95%CI 0.10 to 0.58) p=0.005], FEV1 [0.25litres (95%CI -0.01 to 0.51) p=0.05], PEF [0.81L/sec (95%CI 0.13 to 1.48) p=0.02], MIP [7.40cmH2O (95%CI 1.64 to 13.14) p=0.01] and MSP [3.75seconds (95% CI 0.90 to 6.60) p=0.01]. There was no statistically significant improvement in MEP [5.37cmH2O (95%CI -1.15 to 11.90) p=0.11], MAP [4.41mmHg (95%CI -6.15 to 14.97) p=0.41] or VL [1.14dB (95% CI -1.31 to 3.58) p=0.36]. The study concluded an individually fitted AB significantly improved FVC, FEV1, PEF, MIP and MSP in people with newly acquired tetraplegia.
Improvements in respiratory volumes are an important consideration in the tetraplegic population, as respiratory complications are a leading cause of morbidity and mortality and are associated with reduced lung volumes. Whether the improvements in respiratory function with an AB lead to a reduction in respiratory infections is worthy of future investigation. The improvements in respiratory volumes were carried over into respiratory support for voice as assessed by a significant improvement in MSP and a small increase in VL with the AB. Clinically, an AB is not considered a treatment option to enhance voice, however, this study prompts further consideration. Whilst an AB is considered primarily for BP maintenance when in the seated position, this study failed to show a clinically significant change. The missing data at all time points and the small number of participants may have impacted some results.
This study utilised simple but accurate bedside measures which are available to clinicians to determine the effects of an AB. Since not all patients in this study responded equally to an AB, clinicians may use the same clinical measurements as used in this study to determine whether the application of an AB is warranted for an individual.