Cardell MAX-12 HD - Veterinary Instrumentation

Cardell® MAX-12HD User’s ManualSECTION 9SpO2 MONITORING9.1 IntroductionThe MAX-12HD continuously monitors and displays arterial blood oxygensaturation (SpO2) and pulse rate. The monitor beeps with each pulse beat. Itallows you to choose alarm limits and audible tone volumes. You can selectthe high and low alarm limits for SpO2 and pulse rate, and independentlychoose the volume for alarm and pulse beep tones.The MAX-12HD determines SpO2 and pulse rate by passing twowavelengths of light, one red (660nm) and the other infrared (940nm),through body tissue to a photo detector. Pulse identification is accomplishedby using plethysmographic techniques, and oxygen saturation measurementsare determined using spectrophotometric oximetry principles. Duringmeasurement, the signal strength resulting from each light source depends onthe color and thickness of the body tissue, the sensor placement, the intensityof the light sources, and the absorption of the arterial and venous blood(including the time varying effects of the pulse) in the body tissues.The monitor processes these signals, separating the time invariant parameters(tissue thickness, skin color, light intensity, and venous blood) from the timevariant parameters (arterial volume and SpO2) to identify the pulse andcalculate oxygen saturation. Oxygen saturation calculations can be performedbecause blood saturated with oxygen predictably absorbs less red light thanoxygen depleted blood.Since measurement of SpO2 depends on a pulsating vascular bed, anycondition that restricts blood flow, such as use of a blood pressure cuff orextremes in systemic vascular resistance, may cause an inability to determineaccurate pulse and SpO2 readings.CAUTION: SpO2 sensors are fragile and should be handled with great care.66 M1.0 5-15-09