FYS4250Fysisk institutt - Rikshospitalet....and slicky tricks to prepare you for the exam...

What is a typical question? For example: 1.Mention some different methods for measuring blood pressure, explain the different advantages, disadvantages and eventual risks associated with each method 2.Blood flow is another interesting parameter. Describe how it is possible to measure the blood flow both invasive and non-invasively and explain the advantages, disadvantages for each method. What would be the proper requirements for an amplifier in such a measurement system? 3.Do you know any non-invasive methods of measuring the oxygen concentration in the blood? Give a brief description of the manner of operation, sources of error and advantages/disadvantages 4.Give a short explanation of the function of the human heart. How is it possible to detect patology in the heart function without entering the body?

Image: Grimnes, Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts. ”A sensor is a mediator able to convert one or more measurands or physical variables into an equivalent signal variable of another type of quantity within a frame of a given unity” Pallàs-Areny, Webster, Sensors 2001 What is a sensor?

Image: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts. - Sensor system: ”comprises the total signal path from the measurand to the observer and includes all sensing, conditioning and real-time processing elements in the path” - Electrode: ” An electrode is an electrochemical cell converting charge carriers from ions to electrons or vice versa. An electrode is only a half- sensor in the way that two electrodes are necessary in order to apply a current or read a potential difference in living tissue” - Probe: A ”probe is a broader concept than a sensor. A probe is often comprising multiparameter sensors (e.g. temperature) and may be held by the operator and be equipped with switches and level adjustment facilities. Example: Ultrasound probe” Source: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts. More definitions....

Pressure transducer and Wheatstone bridge Image: Grimnes-Høgetveit. Biomedical Engineering Education & Advanced Bioengineering Learning: Interdisciplinary Concepts.

FYS4250Fysisk institutt - Rikshospitalet Piezoelectric transducer C=εA/x

FYS4250Fysisk institutt - Rikshospitalet Photomultipliers

Membrane potential Nernst equation for potassium K (Nor - Kalium): across a cell membrane with active channels pumping K ions into the cell.

Dipoles in the axon

Neural velocity

The heart

Atrioventricular- block

Ectopic beat

Tachycardia flutter= increased regular frequency

flimmer (norsk) = fibrillation (eng) = = uregelmessig rytme

Ischemia

Metal / electrolyte = electron / ion transitions

Ag / AgCl Non-polarizable electrode

Electrode polarization + skin + deeper layer

Stimulation electrodes

FYS4250Fysisk institutt - Rikshospitalet

FYS4250Fysisk institutt - Rikshospitalet Einthoven triangle

FYS4250Fysisk institutt - Rikshospitalet Wilson central terminal

FYS4250Fysisk institutt - Rikshospitalet Augmented leads

FYS4250Fysisk institutt - Rikshospitalet ”Driven right leg”

FYS4250Fysisk institutt - Rikshospitalet Biopotentail amplifiers

FYS4250Fysisk institutt - Rikshospitalet

FYS4250Fysisk institutt - Rikshospitalet

FYS4250Fysisk institutt - Rikshospitalet The circulatory system

FYS4250Fysisk institutt - Rikshospitalet Typical blood pressures

FYS4250Fysisk institutt - Rikshospitalet Invasive blood pressure measurement

FYS4250Fysisk institutt - Rikshospitalet Harmonic analysis, Fourier

FYS4250Fysisk institutt - Rikshospitalet Heart sounds

FYS4250Fysisk institutt - Rikshospitalet Stethoscopes, spektrogram

FYS4250Fysisk institutt - Rikshospitalet Non-invasive blood pressure

FYS4250Fysisk institutt - Rikshospitalet Ultrasound measurement

FYS4250Fysisk institutt - Rikshospitalet Bloodpressure, oscillometric

FYS4250Fysisk institutt - Rikshospitalet Non-contact tonometry

Indicator-dilution method

Elektromagnetic flowmeter

Electromagnetic flowmeter waveforms

Quadrature-suppression flowm.

Plethysmography

Plethysmography curve

Figure 1 Airways with larynx, trachea, bronchi and alveoles

Figure 2 Lung volume parameters Equation 1 ComplianceC = ΔV / ΔP [L/Pa, L/cmH2O]

Equation 2 Poiseuille [Pa/m 3 /s = pressure / flow rate]

Figure 6 Laplace cylinder model P=T/r

Figure 10 Rebreathing circle with one-directional valves 1 and 2

Figure 13 IR absorption spectra for some anaesthetic agent vapours. Datex Ohmeda Division, Instrumentarium Corporation

Figure 14 Multigas spectrophotometric gas analyzer with rotating filter wheel

pH-measurement

pCO 2 (Severinghaus) electrode

pO 2 (Clark) electrode

Fluorescent dye sensor

pH-sensitive dyes

Pulsoxymetry light absorption