What is the clinical evidence from this study?

Study design: Cross-Sectional. Intervention: Phase IV of Valsalva manoeuvre vs. Phenylephrine ramp method. Primary outcome: Sinoaortic baroreceptor heart rate reflex sensitivity (r = 0.76, p=<0.001).

What question did this study set out to answer?

This research aims to evaluate the sensitivity and latency of the sinoaortic baroreceptor heart rate reflex using different analysis methods.

June 1, 1987Cardiovascular Research

Can sinoaortic baroreceptor heart rate reflex sensitivity be determined from phase IV of the Valsalva manoeuvre?

Q: What are the key findings of this study?

Phase IV of the Valsalva manoeuvre yielded reflex sensitivity values that correlated with the phenylephrine method (r=0.76, p<0.0001), but absolute values differed significantly.

Q: What question did this study set out to answer?

This research aims to evaluate the sensitivity and latency of the sinoaortic baroreceptor heart rate reflex using different analysis methods.

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Key result

Phase IV of the Valsalva manoeuvre yielded reflex sensitivity values that correlated with the phenylephrine method (r=0.76, p<0.0001), but absolute values differed significantly.

Why the study?

Can sinoaortic baroreceptor heart rate reflex sensitivity be accurately determined from phase IV of the Valsalva maneuver compared to the phenylephrine ramp method?

Population

25 subjects with large ranges of age and resting blood pressures

Comparison

Valsalva maneuver vs Phenylephrine ramp method

Design

Cross-sectional

Authors

SSStephanie A. SmithUniversity of Michigan TST. J. StallardQueen Elizabeth Hospital Birmingham MSMahmood M. SalihIraqi University

Discussion

Member takes

Implication

Phase IV Valsalva correlates with but yields different absolute baroreflex sensitivity vs phenylephrine; leaves open need for method standardization before wider use.

Key Points

This research aims to evaluate the sensitivity and latency of the sinoaortic baroreceptor heart rate reflex using different analysis methods.
Twenty-five subjects underwent two standardized Valsalva manoeuvres and received three phenylephrine injections.
Reflex sensitivity and latency were compared between the phenylephrine ramp method and phase IV of the Valsalva manoeuvre.
Statistical analyses were performed using linear regression to assess correlations between methods.
Mean sensitivity values were higher with phenylephrine (6.2 ms.mmHg-1) than with phase IV Valsalva (4.6 ms.mmHg-1, p<0.001) but lower than phase IV systolic overshoot (7.8 ms.mmHg-1, p<0.001).
Reflex latency was shorter with phenylephrine (1084 ms) compared to phase IV Valsalva (2416 ms, p<0.0001) and phase IV overshoot (1504 ms, p<0.0005).
There was a strong correlation between phenylephrine and both Valsalva methods (r = 0.76 for V1, r = 0.80 for V2, p<0.0001).

Study Design

Type

Cross-Sectional (n=25)

Structured PICO

Can sinoaortic baroreceptor heart rate reflex sensitivity be accurately determined from phase IV of the Valsalva maneuver compared to the phenylephrine ramp method?

Population

25 subjects with large ranges of age and resting blood pressures undergoing comparison of baroreceptor reflex sensitivity methods.

Exposure

Valsalva maneuver (whole of phase IV [V1] and phase IV systolic blood pressure overshoot alone [V2])

Comparator

Phenylephrine ramp method (P) (three bolus injections causing transient pressor responses of 20-30 mmHg)

Outcome

Sinoaortic baroreceptor heart rate reflex sensitivity and latencysurrogate

Main Result

Effect estimate: r = 0.76

Absolute Event Rate: 4.6% vs 6.2%

p-value: p=<0.001

While reflex sensitivity derived from phase IV of the Valsalva maneuver correlates with the phenylephrine method, absolute values differ significantly depending on the specific analysis method used.

Limitations

Large errors were introduced into the absolute values obtained when relatively small changes were made to the method of analysis.

Cite This Study

Smith et al. (1987) reported a cross-sectional. Phase IV of Valsalva manoeuvre vs. Phenylephrine ramp method was evaluated on Sinoaortic baroreceptor heart rate reflex sensitivity (r = 0.76, p=<0.001). Phase IV of the Valsalva manoeuvre yielded reflex sensitivity values that correlated with the phenylephrine method (r=0.76, p<0.0001), but absolute values differed significantly.

synapsesocial.com/papers/6a230d293bf314e836cb2c39 https://doi.org/10.1093/cvr/21.6.422

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Implication

Phase IV Valsalva correlates with but yields different absolute baroreflex sensitivity vs phenylephrine; leaves open need for method standardization before wider use.

Can sinoaortic baroreceptor heart rate reflex sensitivity be determined from phase IV of the Valsalva manoeuvre?

Discussion

Member takes

Implication

Key Points

Study Design

Structured PICO

Main Result

Limitations

Cite This Study

Can sinoaortic baroreceptor heart rate reflex sensitivity be determined from phase IV of the Valsalva manoeuvre?

Discussion

Member takes

Implication

Key Points

Study Design

Structured PICO

Main Result

Limitations

Cite This Study

Also Consider

Also Consider