In some examples, a device includes processing circuitry configured to determine a set of correlation coefficient values for values of first and second physiological parameters. The processing circuitry is further configured to determine that the first physiological parameter changes rapidly in a particular time period. The processing circuitry is configured to select a correlation coefficient value associated with the particular time period and determine an updated value of the selected correlation coefficient value in response to determining that the first physiological parameter changes rapidly in a particular time period. The processing circuitry is further configured to determine an estimate of a limit of autoregulation of the patient based on the set of correlation coefficient values and the updated value. The processing circuitry is configured to determine an autoregulation status based on the estimate of the limit of autoregulation and output, for display, an indication of the autoregulation status.