Physiological Measurement and Monitoring Devices PDF

Section 6 Physiological Measurement and Monitoring Devices  Vane-Type Respirometers Wright respirometer – Portable – Uses rotating vanes & a gear mechanism – Most accurate b/t 10-20 LPM – Flow > 300 LPM may damage vane! – Inertia may have some effect Newton’...

Section 6 Physiological Measurement and Monitoring Devices  Vane-Type Respirometers Wright respirometer – Portable – Uses rotating vanes & a gear mechanism – Most accurate b/t 10-20 LPM – Flow > 300 LPM may damage vane! – Inertia may have some effect Newton’s 1st Law Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 2  Wright Respirometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 3  Wright & Haloscale Respirometers Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 4  Peak Flowmeters Pneumotachometer used to measure PEFR @ bedside Types: – Wright peak flowmeter Permanent/reusable – Mini-Wright peak flowmeter Cheaper/lighter/plastic version – Assess peak flowmeter Disposable; very common today; vertical https://www.youtube.com/watch? 5 v=xjNRnba0L-0  Wright Peak Flowmeter Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 6  Mini-Wright Peak Flowmeter Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 7  Assess Disposable Peak Flowmeter Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 8  Asthma Care Plan Green Red All is good, no symptoms Difficulty breathing, coughing, PEFR 80-100% wheezing not helped by Take controller meds medication Trouble walking or talking due Yellow to symptoms Coughing/wheezing, ^ WOB Meds not working Symptoms come on exertion, PEFR less than 50% relieved with medication Peak flow 50-100% CALL MD NOW, if no answer Take controller meds, rescue GO TO ER meds as needed, and call MD if in yellow zone for over 24 hours Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 9  Oxygen Saturation Measurement Hemoglobin and Its Variants CO-Oximetry – Principle of operation Pulse Oximetry – Principle of operation Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 10  Hemoglobin and Its Variants Hgb reversibly binds w/ O2 – HbO2 – RHb Carboxyhemoglobin (COHb) – Bound to CO – Affinity = 200-250 x Methemoglobin (MetHb) – Cannot bind w/ O2= – Brown in color Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 11  CO-Oximetry Determines fractional Hb Uses spectrophotometry – RBC’s are hemolyzed to releas Hb – Isobestic point: wavelength where 2 or more variants (Hb, HbO2, HbCO) absorb same amount of light – By knowing amount of light absorbed, concentration can be determined Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 12  End Tidal CO2 Monitoring Principle of Operation Capnography Sensor Position – Mainstream – Sidestream – Proximal diverting Colormetric End Tidal CO2 Determination – Principle of operation Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 13 Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 14  Pulmonary Measurement Devices Volume Displacement Devices Body Plethysmographs Pneumotachometers Vane-Type Respirometers Peak Flowmeters Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 15  Volume Displacement Devices Water seal spirometer – Industry standard for many years – Exhaled gas enters a counterweighted bell – CO2 absorber Dry rolling seal spirometer – “a frictionless piston” – Oriented horizontally – Plastic instead of metal Bellows spirometer – Gas entering bellows causes it to expand 16 Collins Water Seal Spirometer http://www.bing.com/videos/search? q=water+seal+spirometer&view=detail&&& mid=FE508D9DCABB5C168D05FE508D9 DCABB5C168D05&rvsmid=FE508D9DCA BB5C168D05FE508D9DCABB5C168D05# view=detail&mid=FE508D9DCABB5C168D 05FE508D9DCABB5C168D05 17  Stead-Wells Water Seal Spirometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 18  Dry Rolling Seal Spirometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 19  Bellows Spirometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 20  Body Plethysmographs Uses Boyle’s Law to measure changes in thoracic V P in box changes w/ or in V Pneumotachometer measures flow May also derive: – RAW – FRC Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 21  Body Plethysmograph Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 22  Pneumotachometers Measure gas flow May obtain V indirectly: Volume = Flow x Time Types: – Thermal anemometer Measures current used to keep grid “hot” – Fleisch pneumotachometer Relies on P differential to measure flow – Venturi pneumotachometer Measures P difference along Venturi tube (Δ in P proportional to Flow) Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 23  – Pitot tube flow sensor Measures difference in b/t incoming flow (ram) & static P (ambient) – Vortex sensor Uses vortex shedding principle Turbulent flow impedes transmission of ultrasonic waves Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 24  Thermal Anemometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 25  SensorMedics Mass Flow Sensor (also a thermal anemometer) Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 26  Fleisch Pneumotachometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 27  Venturi Pneumotachometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 28  Pilot Tube Pneumotachometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 29  Vortex Sensor Pneumotachometer Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 30  Indirect Calorimetry Measurement of Oxygen Consumption and Carbon Dioxide Production – Minute ventilation – Tidal volume – REE (resting energy expenditure) – RQ Nutritional Assessment – Ventilator weaning – Diet/exercise prescription Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 31  Apnea and Home Sleep Monitors Apnea Monitor Types – Inductive plethysmography – Impedance plethysmography Home Sleep Monitors – Impedance channel – SpO2 channel – Heart rate channel – Airflow channel Copyright ©2005 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 32