A method for giving a measurement of quality for impedance based respiration monitoring is disclosed comprising attaching a lead 20 to a subject 30, the lead being connected to a monitor 10, and receiving a signal from the lead, the lead being used for impedance respiration monitoring； estimating amplitude of cardiovascular artefact, CVA, derived from the signal of the lead； estimating amplitude of respiration derived from the signal of the lead； calculating a quality factor for the lead based on the estimated amplitude of CVA and the estimated amplitude of respiration and indicating the quality factor for the lead to the user via the monitor. The quality factor may be calculated by dividing the estimated amplitude of the respiration dividing by the estimated amplitude of CVA or vice versa. The method can be used to test each lead for quality factor in turn and indicating the optimal lead for respiration monitoring. This can be preferable to using trial and error to find out which lead would be the optimal lead in different respiration monitoring situations.
