What characteristic is typical of normal TCD waveforms?

Normal Transcranial Doppler (TCD) waveforms are characterized by a brisk upstroke, which reflects the rapid acceleration of blood flow during systole. This upstroke indicates adequate cerebral perfusion and is a sign that the arteries are functioning normally to supply blood to the brain. In a typical TCD waveform, this upstroke is followed by a clear and distinct downstroke and is characterized by distinct peaks corresponding to the systolic and diastolic phases of the cardiac cycle.

The brisk upstroke indicates healthy dynamics of blood flow in the cerebral vessels, allowing for the assessment of various conditions affecting cerebral perfusion. A waveform showing a deficient or flat upstroke may suggest an underlying issue, such as poor vascular reactivity or compromised blood flow, which is not typical of normal waveforms. This is crucial in the intraoperative setting, where continuous monitoring of cerebral blood flow is essential for patient safety.