PTSD Severity and Neurovascular Responses to Device Guided Slow Breathing: Acute and Long-term Effects Open Access

Vemulapalli, Monica (Spring 2020)

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Background: Posttraumatic stress disorder (PTSD) is associated with an increased risk for developing hypertension and cardiovascular disease (CVD). We previously showed that device- guided slow breathing (DGB) acutely lowers muscle sympathetic nerve activity (MSNA) and improves hemodynamics in patients with PTSD. However, it remains unclear whether the physiological responses to DGB depend on the severity of PTSD symptoms. Hypothesis: Study 1. Neural and cardiovascular responses to acute DGB will be heightened in severe PTSD. Study 2. Chronic use of DGB will decrease resting MSNA, blood pressure (BP) and heart rate (HR) in severe PTSD. Methods: The clinician-administered PTSD scale (CAPS) was used to confirm the diagnosis of PTSD (CAPS score ≥45) and the severity of PTSD symptoms. To test our hypothesis, we recruited 25 veterans with PTSD (age, 36±2 years). The CAPS scores in our sample ranged from 45 to 95 with a median score of 70 that was used to separate study participants into two groups: Moderate (CAPS ≤70, n=13) and Severe (CAPS >70, n=12). Within each group, participants were randomized to either breathing with the DGB device or with an identically looking Sham device. Beat-to-beat blood pressure (BP) via finger plethysmography, HR via EKG, HR variability (HRV) and MSNA using microneurography were measured for both studies. Study 1. Measurements were made at baseline and during 10 minutes of breathing with either the DGB or sham device in all 25 participants. Study 2. Resting measurements were taken before and after 8 weeks of daily DGB only in a subset of 12 participants with PTSD. Results: Study 1. As we hypothesized, HR (interaction, p=.049) and MSNA (interaction, p=0.025) significantly decreased more with DGB compared to Sham in the severe PTSD group compared to the moderate group. Changes in BP and HRV were not different between the groups. Study 2. Resting MSNA decreased (interaction, p = .011) after 8 weeks of DGB in severe PTSD, but other variables were comparable between severe and moderate PTSD. In summary, the acute and long-term effects of DGB depends on PTSD severity, suggesting that individuals with severe PTSD could benefit more from DGB. 

Table of Contents

Introduction 1

Study 1

Methods and Protocol 10

Data Analysis 14

Statistical Analysis 15

Results 16

Study 2

Methods and Protocol 23

Data Analysis and Statistics 24

Results 24

Discussion 31

Limitations 34

Future directions 35

Conclusion 36

Appendix 37

References 59 

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