Respiratory monitoring with a new impedance plethysmograph.

A new impedance plethymograph respiratory monitor, (AR-8800), was tested on anaesthetised dogs. Decreases in tidal volume and total apnoea were brought about by partial and complete airway obstruction and by partial and total muscle paralysis. The changes in respiration were reliably detected by the monitor and its alarms activated within 15-20 seconds. The misinterpretation of gross body movement as normal breathing did not occur. Our findings suggest that the AR-8800 is a safe and dependable monitor which has distinct advantages and may be of particular use in the monitoring of patients at risk of developing respiratory depression or obstruction, whether in the intensive care unit, the general ward or at home.