Comparison of Autonomic Reactions during Urodynamic Examination in Patients with Spinal Cord Injuries and Able-Bodied Subjects

PLoS ONE, 2016 · DOI: 10.1371/journal.pone.0161976 · Published: August 30, 2016

Simple Explanation

This study compares heart rate variability (HRV) and systolic blood pressure (SBP) changes of spinal cord injury (SCI) patients during urodynamic study (UDS) with able-bodied controls. Autonomic dysfunction frequently accompanies spinal cord injuries (SCI). SCI patients may also experience autonomic dysreflexia (AD), which causes autonomic dysfunction. Heart rate variability (HRV) was developed as a non-invasive, practical and reproducible method for quantitative evaluation of autonomic activity.

Study Duration

January 2012 to December 2012

Participants

24 complete suprasacral SCI patients (12 tetraplegia and 12 paraplegia) and 12 age-matched able-bodied volunteers

Evidence Level

Not specified

Key Findings

1
Only control subjects displayed significant elevation of SBP during Foley catheter insertion compared to resting values.
2
Both control and tetraplegic groups experienced significant elevation of SBP at maximal bladder capacity compared to resting values. Tetraplegic values were also significantly greater than the other two groups.
3
Tetraplegic patients experienced BP elevation but did not experience significant changes in HRV during bladder distension.

Research Summary

This study compares heart rate variability (HRV) and systolic blood pressure (SBP) changes of spinal cord injury (SCI) patients during urodynamic study (UDS) with able-bodied controls. Tetraplegic patients experienced BP elevation but did not experience changes in HRV during bladder distension. This finding may imply that different neurological pathways contribute to AD reaction and HRV changes during bladder distension. However, profound AD (SBP increment >50 mmHg) during UDS in tetraplegic patients was associated with corresponding changes in HRV.

Practical Implications

AD and HRV Pathways

Different neurological pathways may contribute to AD reaction and HRV changes during bladder distension.

HRV Monitoring

HRV monitoring may be useful in SCI patients with significant AD during UDS to detect potential complications.

Further Studies

Further research is needed to elucidate whether concomitant BP and HRV recording provide more accurate information in AD detection.

Study Limitations

1
Completeness of lesion was judged by sensory and motor tests rather than a sympathetic test.
2
The circulatory noradrenaline level was not examined in tetraplegic patients.
3
Small study subjects, particularly only five patients per subgroup, may also limit our analysis with respect to LF/HF elevation in tetraplegia patients with severe AD.

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