B40/B20 Patient Monitor12-2OverviewImpedance respiration is measured across the thorax. When the patient is breathing or isventilated, the volume of air changes in the lungs, resulting in impedance changes between theelectrodes Respiration rate is calculated from these impedance changes, and a respirationwaveform is displayed on the monitor screen.Figure 12-1 Impedance respiration measurement connectorRespiration detectionThe respiration rate is the sum of the respirations that have exceeded the detection limit.When starting respiration monitoring, the system “learns” the patient’s respiration pattern. Therespiration rate is calculated from impedance changes and a respiration waveform isdisplayed. Respiration detection is not dependent on the size of the waveform. Size is for visualpurposes only.The dotted lines present the zero line and the detection limit. The signal strength produced by arespiration should thus exceed this minimum limit to be included in the respiration ratecalculation. Peaks within the grids are not calculated.If the detection mode is AUTO, the grid lines present the minimum limits. The limits in use maybe larger. The RR value could include fewer respirations than indicated by the gridline.NOTES:• Electrical devices, such as electrosurgery units and infrared heaters, that emitelectromagnetic disturbance may cause artifact or disable the respiration measurementcompletely.ECG andimpedancerespirationconnector%
