Can we use short recordings for assessment of dynamic cerebral autoregulation? A sensitivity analysis study in acute ischaemic stroke and healthy subjects.

ObjectiveIt is unclear whether the duration of recordings influences estimates of dynamic cerebral autoregulation (dCA). Therefore, we performed a retrospective study of the effects of reducing recording durations on dCA estimates; with the potential to inform recording duration for reliable estimates in challenging clinical populations.ApproachSeventy-eight healthy control subjects and 79 acute ischaemic stroke (AIS) patients were included. Cerebral blood flow (CBF) velocity was recorded with transcranial Doppler (TCD) and continuous blood pressure (BP) with a Finapres device. The autoregulation index (ARI), derived with transfer function analysis (TFA), was calculated for recording durations at one-minute intervals between 1 and 5 min using the same starting point of each recording.Main resultsThough recording duration did not affect the overall ARI value, when compared to control subjects, AIS patients had significantly lower ARI values for durations between 3 and 5 min (p   SignificanceReducing recording durations from 5 to 3 min can still provide reliable estimates of ARI, and may facilitate CA studies in potentially medically unstable AIS patients, as well as in other patient groups.