What is a significant consequence of unstable blood pressure effects on cortical SSEPs?

Unstable blood pressure can have a profound impact on the quality of sensory evoked potentials, particularly cortical somatosensory evoked potentials (SSEPs). When blood pressure fluctuates, it can lead to inconsistent perfusion of the brain, which in turn affects the neural response measured by SSEPs.

Fluctuating amplitudes are often observed under these conditions because the variations in blood pressure can alter the excitability of the cortical neurons that generate the SSEP responses. If blood pressure drops, there may be reduced blood flow, leading to lower amplitudes due to less neural activation. Conversely, if blood pressure increases rapidly, this could lead to transient hyperperfusion, which might enhance the amplitude temporarily, resulting in inconsistent readings.

The variability in blood supply ultimately causes the amplitude of the SSEPs to change rather than remain stable. This is critical for monitoring during surgery as it can indicate issues with cerebral perfusion and necessitate prompt intervention to stabilize the patient's condition. In contrast, the other responses do not directly capture the dynamic changes in neural response that result from blood pressure fluctuations.