Autonomic Nervous System Dysfunction After Spinal Cord Injury

Garstang, Susan V.; Miller-Smith, Stacey A.

doi:10.1016/j.pmr.2007.02.003

Cited by 91 publications

(86 citation statements)

References 63 publications

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“…A reduced HRR may reflect an intrinsic deficiency in vagal reactivation, an impairment in baroreceptor sensitivity, deconditioning associated with highlevel SCI, some combination of these factors 1,2,9 or simply a low HRpeak achieved. Although an impairment in baroreceptor sensitivity has been widely described in SCI, 1,17,18 the contribution of deconditioning is suggested by the significant association between peak VO 2 and HRR in SCI subjects in this study (Table 3). In fact, Sedlock et al…”

Section: Discussionmentioning

confidence: 59%

Post-exercise heart rate recovery in individuals with spinal cord injury

et al. 2010

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Study design: Prospective comparison of spinal cord injured (SCI) subjects and ambulatory subjects. Objectives: To determine the effects of the presence and level of SCI on heart rate recovery (HRR). Setting: Outpatient SCI center. Methods: HRR was determined in 63 SCI subjects (26 with tetraplegia, 22 with high-level paraplegia, 15 with low-level paraplegia) and 26 ambulatory subjects. To adjust for differences in heart rate reserve between groups (HRpeak minus HRrest), HRR was also 'normalized' to a range of 1 at peak heart rate and to 0 at 8 min, and the shapes of HRR curves were compared. Results: Although absolute HRR was similar between high-and low-level paraplegia, it was significantly more rapid in participants with paraplegia at 2, 5 and 8 min after exercise than in those with tetraplegia (39±14 vs 29±14 b.p.m., Po0.05; 51±14 vs 33±16 b.p.m., Po0.01 and 52±16 vs 36 ± 17 b.p.m., Po0.01, respectively). HRR among ambulatory subjects was more rapid than among those with tetraplegia at all time points in recovery. However, when normalized for heart rate reserve, HRR was significantly more rapid in tetraplegic subjects (Po0.001 vs paraplegia and ambulatory subjects). Conclusion: In SCI, HRR is strongly associated with the peak exercise level and peak heart rate achieved during exercise testing.

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Section: Discussionmentioning

confidence: 59%

Post-exercise heart rate recovery in individuals with spinal cord injury

et al. 2010

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“…2 Vasoconstriction induces an elevated BP, and thereby the central nervous system tries to lower BP by activating injury-excluded parasympathetic stimulation of the heart, which triggers a state of bradycardia and vasodilation above the site of injury. 10 The hemodynamic instability alters normal blood flow. Bradycardic hypotension results in hypoperfusion, which can have a negative effect on drugs administered through intravenous or intraarterial routes and could decrease microvascular blood flow to certain organs.…”

Section: Resultsmentioning

confidence: 99%

Spinal cord injury sequelae alter drug pharmacokinetics: an overview

et al. 2011

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Study design: Literature review. Objectives: Critical review of the literature published on the physiological alterations caused by spinal cord injury (SCI) and their effect on the pharmacokinetic parameters of commonly employed drugs. The review introduces the most recent treatment protocols of a variety of drugs, enabling the modern clinician to apply efficacious and cost-effective solutions to the pharmacological treatment of SCI patients. Methods: Studies published in international indexed journals up to January 2011 were selected from the PubMed database. Results: The review evaluated the sequelae of SCI and their effect on pharmacological processes. The results demonstrated that these alterations affected the pharmacokinetics of drugs commonly administered to SCI patients, such as antibiotics, muscle relaxants, immunosuppressants and analgesics. Conclusion: There are multiple etiologies to SCI and patients present with varying degrees of impairment. Factors such as level of injury and completeness of the injury create a very heterogeneous population within the SCI community. The heterogeneity of this population creates a problem when trying to standardize pharmacokinetic (PK) parameters. It is because of this that specific physiological alterations must be linked to changes in PK and be identified within the clinical setting. This relationship between physiology and PK enables the clinician to be alert for possible pharmacological complications in individual patients based on their clinical manifestations. Future research should aim to develop rigorous therapeutic guidelines tailored to the diverse manifestations of SCI so as to provide effective, affordable and safe pharmacotherapy.Spinal Cord (2011) 49, 955-960;

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“…Subjects with SCI may exhibit decreased cardiac output as a consequence of impaired vasomotor reflexes, reduced sympathetic outflow and decreased venous return, secondary to the lack of muscle contraction in the extremities. 16,17 In such individuals, maintenance of blood pressure levels is thought to be dependent on the activation of the hormonal regulatory system, such as the reninangiotensin-aldosterone axis. 17 In turn, chronic upregulation of this system would potentially stimulate LV remodeling and diastolic dysfunction.…”

Section: Discussionmentioning

confidence: 99%

Altered left ventricular diastolic function in subjects with spinal cord injury

et al. 2010

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Study design: This is cross-sectional study. Objectives: The aim of this study is to investigate the cardiac structure and function of subjects with spinal cord injury (SCI) and the impact of metabolic, hemodynamic and inflammatory factors on these parameters. Setting: São Paulo, Brazil. Methods: Sixty-five nondiabetic, nonhypertensive, sedentary, nonsmoker men (34 with SCI and 31 healthy subjects) were evaluated by medical history, anthropometry, laboratory tests, analysis of hemodynamic and inflammatory parameters and echocardiography. Results: Subjects with SCI had lower systolic blood pressure and higher levels of C-reactive protein and tumor necrosis factor receptors than the healthy ones. Echocardiography data showed that the SCI group presented similar left ventricular (LV) structural and systolic parameters, but lower initial diastolic velocity (Em) (9.2 ± 0.5 vs 12.3 ± 0.5 cm s À1 ; Po0.001) and higher peak early inflow velocity (E)/Em ratio (7.7±0.5 vs 6.1±0.3; P ¼ 0.009) compared with the able-bodied group, even after adjustment for systolic blood pressure and C-reactive protein levels. Furthermore, injured subjects with E/Em 48 had lower peak spectral longitudinal contraction (Sm) (9.0±0.7 vs 11.6±0.4 cm s À1 ; Po0.001) and cardiac output (4.2 ± 0.2 vs 5.0 ± 0.2 l min À1 ; P ¼ 0.029), as well as higher relative wall thickness (0.38±0.01 vs 0.35±0.01; P ¼ 0.005), than individuals with SCI with E/Emo8, but similar age, body mass index, blood pressure, injury level, metabolic parameters and inflammatory marker levels. Conclusion: Subjects with SCI presented impaired LV diastolic function in comparison with ablebodied ones. Moreover, worse LV diastolic function was associated with a pattern of LV concentric remodeling and subclinical decreases in systolic function among injured subjects. Overall, these findings might contribute to explain the increased cardiovascular risk reported for individuals with SCI.

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Autonomic Nervous System Dysfunction After Spinal Cord Injury

Cited by 91 publications

References 63 publications

Post-exercise heart rate recovery in individuals with spinal cord injury

Post-exercise heart rate recovery in individuals with spinal cord injury

Spinal cord injury sequelae alter drug pharmacokinetics: an overview

Altered left ventricular diastolic function in subjects with spinal cord injury

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