Blood Pooling Prevention in Management of OH
The application of external counter pressure through devices such as abdominal binders or pressure stockings is thought to decrease capacitance of the vasculature beds in the legs and abdominal cavity, both major areas of blood pooling during seating or standing.
Discussion
The studies examining external pressure interventions generally test different pressure conditions with the same group of individuals (e.g. with and without stockings) either in a randomized order (RCT) (Wadsworth et al. 2012; Hopman et al. 1998a,b) or assigned order (non-RCT) (Helmi et al. 2013; Rimaud et al. 2012, 2008; Krassioukov & Harkema 2006; Kerk et al. 1995).
The application of these interventions must be interpreted with caution, as none of these studies assessed more than the effect of pressure application during acute phase. Whether these effects would persist with chronic use or cause any detrimental effects upon removal after extended use is unknown. Rimaud et al. (2008), after observing a decrease in venous capacitance, suggested that graduated compression stockings worn by individuals with paraplegia may prevent blood pooling in the legs. However, these effects were observed when the subjects were at rest and in the absence of orthostatic stress. Rimaud et al. (2012) found that with the graduated compression stockings, sympathetic activity increased and parasympathetic activity decreased after maximal exercise in men with SCI. Kerk et al. (1995) reported that application of an abdominal binder did not significantly improve cardiovascular or kinematic variables at submaximal or maximal levels of exercise. A single RCT (n=14) by Wadsworth et al. (2012) found that abdominal binders did not significantly affect mean arterial pressure. In his review, Bhambhani (2002) concluded that the use of abdominal binders does not influence cardiovascular responses. Conversely, in another RCT (Hopman et al. 1998b), demonstrated in a small group of subjects with SCI (n=9) that stockings and an abdominal binder have an effect on cardiovascular responses during submaximal exercises, but not during maximal exercises (Hopman et al. 1998a). Krassioukov & Harkema (2006) found that the use of a harness (which applies abdominal pressure) during locomotor training increased diastolic BP in those with SCI, but not in able-bodied individuals. Therefore, there is level 2 evidence (from 1 RCT) that pressure from elastic stocking and abdominal binders may improve cardiovascular responses during submaximal, but not maximal, arm exercise.
Conclusion
There is conflicting evidence based on limited research that elastic stockings/abdominal binders have any effect on cardiovascular responses in individuals with SCI.
There is level 2 evidence (Krassioukov & Harkema 2006) that application of a harness in individuals with SCI could alter baseline cardiovascular parameters and orthostatic responses.
