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FYS 4250. Lecture 1. Welcome to FYS 4250. Today’s program A short introduction to the course Case 1. Introduction to FYS 4250. What is the main goal for FYS 4250? To give the students an overview of the basic concepts of biomedical instrumentation. Seemallorca.com.
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FYS4250 Lecture 1
Welcome to FYS 4250 Today’s program • A shortintroduction to thecourse • Case 1
Introduction to FYS 4250 • What is themain goal for FYS 4250? • To givethe students an overviewofthebasicconceptsofbiomedicalinstrumentation Seemallorca.com
Introduction to FYS 4250 • What should the student be capable of? • Know the different medical technologies, describe the use, area of application and working principle, limitations, distinctive technological feature, strengths/weaknesses, sources of errors. Both alone and compared to other similar technologies www.withfriendship.com
Introduction to FYS 4250 • How shallwe be able to reachour goals? • 16 Patient cases, eachintroducing different aspectsofmedicaltechnology • 2 Repetitionsofthemaintechnologies • 1 Field trip to Oslo University Hospital • 2 Exams (Mid-term exam = 40% ofyour final grade, and the final exam = 60% ofyour final grade) Epicrapbattlesofthistory.wikia.com
Introduction to FYS 4250 • What about the practical issues? • We will use the “Medical Instrumentation, 4th edition, John Webster” • We will use some offprints from other sources • The time schedule will be published on the homepage, any departure from this will be published in ”messages” at least 24h before the lecture • Other practical issues will be delt with from the institute
Introduction to FYS 4250 • Anyother questions? - Okay, let’s start. You’llsoon start to think as a biomedicalengineer
Case 1 - 47 years old male, no chronic diseases, father died from cerebral haemorrage 63 years old. His mother is still alive, no diseases.
Case 1 • The patientcomes to theemergencyroomcomplainingof severe shortnessofbreath and coughing, several episodes in thepastlasting a day or two. He had an episode ofrheumaticfever at age 14 years, deniesanyabuseofdrugs or alcohol, notobacco. On examination, heart rate is between 110 – 130 bpm, respiratory rate of 24 breaths per minute, withoxygensaturationof 92% oxygen. Coughing, producingfrothysputumwith a pinkish tint. Bilateral inspiratorycracklescan be heard in thelowerlungfields. - What is the most likely diagnosis?
Case 1 • Seems reasonable that the problems are related to the heart or the lungs. Typically an examination will start with the heart to exclude any possible life-threatening arrythmias - What will you do now?
Case 1 • Electrocardiogram, ECG = measuring the electrical activity of the heart cnx.org - What will you do now?
Case 1 • Electrocardiogram, ECG = measuring the electrical activity of the heart cnx.org - How is the electrical activity generated?
Case 1 • Action potential of a single heart cell Kvhs.nbed.nb.ca
Case 1 • Action potential of a single heart cell - How is this electricity distributed?
Case 1 • Cardiac conduction system www.beltina.org - How is this seen as an ECG?
Case 1 • Regional electric activity - What does the final signal look like?
Case 1 • The ECG-complex - How can we obtain this signal?
Case 1 • The Einthoven triangle, placement of bipolar electrodes. Kirchhof says: I+III=II - How can we obtain this signal?
Case 1 • Converting ion-current in the body to electronic current outside the body through the electrodes - Three leads into one signal?
Case 1 • Wilson central terminal, unipolar electrodes - Still a small, noisy signal. What to do?
Case 1 • Augmented leads: 50% increased amplitude - Still too much noise, what to do?
Case 1 • The patient is taken into a room for ECG-examination. However, the signal appears to be noisy and difficult to interpret. - Where do the noise come from?
Case 1 • The ECG-signals are very weak - Still, where do the noise come from?
Case 1 • Alternative 1, electric field pickup
Case 1 • Alternative 2, magnetic field pickup
Case 1 • Alternative 3, common mode voltage
Case 1 • Introducing the ideal operational amplifier • Infinite open loop gain • Infinite input impedance • Zero output impedance • Zero offset voltage • Infinite bandwith
Case 1 • The ideal operational amplifier can be summed up in two golden rules: • The output attempts to do whatever is necessary to make the voltage difference between the inputs zero • The input draws no current www.dummies.com
Case 1 • How to build an ECG-amplifier - Problems solved?
Case 1 • Faraday cage is the ultimate solution - Practical solution?
Case 1 • Driven right leg is the practical solution
Case 1 • Driven right leg + ECG amplifier gives us this ECG signal (the right, a regular sinus to the left) • No P-waves and irregular ventricular response Afib.utorontoeit.com - What is the diagnosis?
Case 1 • Answer: Atrial fibrillation (Birkebeiner disease) Afib.utorontoeit.com - Caused of?
Case 1 • Answer: Because of the loss of atrial contraction, the atrial fibrillation has caused a pulmonary edema. -This is most probably caused by rheumatic heart disease - Atrial fibrillation have an increasing incidence with age, affecting 10% of patients older than 75 years of age - Atrial depolarisation, often at rates exceeding 300-400 bpm - The most common arrhythmia for which patients seek doctor Toy, Patlan, Cruse, Faustinella, Case Files Internal medicine, McGrawhill - Is it dangerous?
Case 1 • Answer: Yes • It may trigger a rapid ventricular rate leading to myocardial ischemia or heart failure • Atrial fibrillation is a common cause of stroke, due to thrombus formation in the noncontractile atria The two most common causes are hypertensionand coronary atherosclerosis If patient is hemodynamically unstable, urgent cardioversion is indicated. Not all patients can be cardioverted, and the longer the fibrillation, the more likely the patient is to stay there because of electrical remodeling of the heart. Toy, Patlan, Cruse, Faustinella, Case Files Internal medicine, McGrawhill - What is rheumatic heart disease?
Case 1 • In this case, the cause of the patient’s atrial fibrillation seems to be mitral stenosis, a late sequela of acute rheumatic fever Toy, Patlan, Cruse, Faustinella, Case Files Internal medicine, McGrawhill www.healthcentral.com - Could this be diagnosed by other means?
Case 1 • Yes, by a stethoscope. A loud S1 and an opening snap following S2 with a low-pitched diastolic rumble. • Yes by ultrasound • Yes by MRI • Yes by CT More about this later in the course Toy, Patlan, Cruse, Faustinella, Case Files Internal medicine, McGrawhill - And the prognosis?
Case 1 • Very good if converted properly by surgery or medications Toy, Patlan, Cruse, Faustinella, Case Files Internal medicine, McGrawhill