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Non-pharmacological Interventions for Orthostatic Hypotension

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To date, studies addressing the non-pharmacological management of OH in acute SCI are limited. There have been several more non-pharmacological modalities of treatment studied in the chronic SCI population, including fluid intake and salt loading, use of elastic stockings and abdominal binders, harness application, whole-body vibration, exercise, and standing training (refer to SCIRE Orthostatic Hypotension rehabilitation evidence chapter).

Non-pharmacological Management of Orthostatic Hypotension during Acute SCI

Three studies have examined the non-pharmacological management of OH during acute SCI with electrical stimulation and tilt table verticalization. In a RCT by Elokda et al. (2000), five patients who were, on average, 3 weeks post SCI were examined during a tilting procedure with or without functional neuromuscular stimulation (FNS) of the knee extensors and foot plantar flexors. The effect of FNS on postural-related orthostatic stress was measured at 0°, 15°, 30°, 45°, 60° tilt angles. Measures of systolic BP at 15° (p=0.05), 30° (p<0.001), 45° (p=0.04), and 60° (p=0.07) positions without FNS were significantly lower than with stimulation, while measures of diastolic BP at 30° (p=0.02) and 45° (p=0.01) without stimulation were lower than with FNS. Sampson et al. (2000) studied six patients in a RCT who underwent a tilting procedure at four functional electrical stimulation (FES) intensities (0, 48, 96, and 160 mA). Half of the participating subjects recruited for this study had an acute/subacute SCI as they were studied at 8-10 weeks post injury, while the other half were 10-14 years post injury (chronic phase of SCI). Patients were tilted by 10° increments from 0° to 90° during separate stimulation of the quadriceps and pretibial muscles, and at the patellae and malleoli. The authors observed a dose-dependent increase in BP, regardless of stimulation site. The mean systolic (p=0.001) and diastolic BP (p=0.0019) increased significantly with increasing stimulation intensities. Tesini et al. (2013) recruited nine patients who were a median of 34 days after injury. Participants were positioned on a tilt-table at increasing angles (0°, 15°, 30°, 45°, 60°, and 70°) with varying electrical stimulation intensities being used according to each patient. The tilting procedure was conducted for three sites of stimulation, which included the abdominal muscles, lower limb muscles, and a combination of abdominal and lower limb muscles, as well as a baseline measure without stimulation. Although a tendency towards the beneficial use of ES for OH was seen, BP was not observed to differ significantly between the interventions at any degree of incline (p>0.05 for all); however, the numbers were small.

In a more recent pre-post study, Daunoraviciene et al. (2018), found that tilt table verticalization was effective at significantly decreasing heart rate and systolic BP in SCI populations. Although this study aimed to assess motor function, there were significant effects on cardiovascular parameters which have implications for the management of OH.

Conclusion

There is level 2 evidence (from one RCT, one PCT and one pre-post; Tesini et al., 2013; Elokda et al., 2000; Sampson et al., 2000) that tilt tables in combination with functional electrical stimulation can effectively raise blood pressure in an SCI population, but not with tilt tables alone.

There is level 4 evidence (from one pre-post study; Daunoraviciene et al., 2018) that tilt table verticalization can significantly lower cardiovascular parameters in SCI patients.

  • The use of functional electrical stimulation in combination with tilt tables may be effective for the management of orthostatic hypotension during the acute and subacute phase post SCI.

    Tilt table verticalization may be effective for lowering heart rate in patients post SCI.