13. Blood Pressure. Millie Grim Geek Rea New Zealand

Transcription

1 13. Blood Pressure Millie Grim Geek Rea New Zealand 1

2 Presentation Outline Explanation of Blood Pressure (BP) Methods of Measurement Inherent Variation exploration of the physiological variables Effect on Measurement & Diagnosis 2

3 The Problem 13. Invent Yourself: Blood pressure Study the accuracy of various methods to measure blood pressure. Propose an interesting study involving blood pressure and pulse. 3

4 My Problem Blood Pressure is inherently variable. Investigate how this phenomenon affects the reliability of different methods used to diagnose hypertension. 4

5 Explanation of Blood Pressure 5

6 Aorta Brachial Artery 6

7 Hypertension High Blood pressure > 130/80 mmhg 7

8 Effects of Hypertension Elevated BP [Hypertension] is the main risk factor for cardiovascular disease, the number one cause of mortality worldwide. -World Health Organisation 8

9 Importance of reliability Diagnosis Hypertension Normal Positive TP (True Positive) FP (False Positive) Negative FN (False Negative) TN (True Negative) 9

10 Methods of Measurement ABPM HBPM Out of office Clinic BP In office 10

11 Methods - out of office ABPM (Ambulatory BP Monitoring) 11

12 Methods- out of office HBPM (Home BP monitoring) 12

13 Methods- in office Clinic BP measurement 13

14 Inherent Variation 14

15 Inherent Variation 15

16 Model Heart 16

17 Set up One way valve, heart 17

18 Set up Air pressure Sensor Constant Head Apparatus T-Junction Fake arm Piston One way valve 18

19 Example graph Pressure (KPa) Time (s) 19

20 Example graph Pressure (KPa) Time (s) 20

21 Poiseuille's Law BP F L n r 4 F = Flow L = vessel length n = blood viscosity r = vessel radius 23

22 Components of BP BP CO PR BP = Cardiac Output Peripheral Resistance 24

23 Components of BP BP CO PR BP = Cardiac Output Peripheral Resistance 25

24 Cardiac Output Cardiac Output = Stroke Volume Heart Rate CO = SV HR 26

25 Cardiac Output CO = SV HR 27

26 Increasing Stroke Volume Begins pumping 28

27 Cardiac Output CO = SV HR 29

28 Increasing Heart Rate 30

29 Poiseuille's Law BP F L n r 4 BP PR 31

30 Peripheral Resistance Vasodilation 32

31 Peripheral Resistance Vasoconstriction 33

32 Components of BP BP CO PR BP = Blood Pressure CO=Cardiac Output PR=Peripheral Resistance 34

33 Effect of Stress Cardiac Output Peripheral Resistance 35

34 Effect of Stress Cardiac Output Peripheral Resistance 36

35 Effect on Measurement & Diagnosis 37

36 Influence of setting 38

37 Influence of setting Exercise or stress Working Eating Resting 39

38 Inherent Variation 40

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43 45

44 Comparing Methods 46

45 Comparing Methods 47

46 Statistical simulation 48

47 Conclusion Blood Pressure is inherently variable. Investigate how this phenomena affects the reliability of different methods used to diagnose hypertension. 49

48 Conclusion-Methods ABPM HBPM Clinic BP Location Out of office Out of office In office 50

49 Conclusion-Methods ABPM HBPM Clinic BP Number of measurements many some one 51

50 Inherent Variation BP CO PR 52

51 White Coat Hypertension 53

52 Conclusion-Methods ABPM HBPM Clinic BP Reliability: Reliable Reliable Less reliable 54

53 Acknowledgements Otis Rea Sophie Mance Katy Bell Murray Chisolm Kerry Parker Fiona Wilson Moira Wilson David Rea & Everyone who let me take their blood pressure 55

54 Bibliography -oscillometric model - importance of CBP & pressure changes, PP amplification -mathematical model -cuff everything -abpm -palpatory -evaluation of wrist ABPM -role of abpm -comparison of wrist and arm -eguchi et al hr variation -stress

55 13. Blood Pressure Millie Grim Geek Rea, New Zealand 57

56 Study the accuracy of various methods to measure blood pressure. I investigated the accuracy of ABPM, HBPM, and Clinical measurement for a diagnosis of hypertension Propose an interesting study involving blood pressure and pulse. I created a model heart with pulse and pressure 58

57 Extra Slides 59

58 Components of BP Pressure = Flow Resistance = C. O. PR 60

59 Causes of Hypertension BP = CO PR 61

60 Causes of Hypertension BP = C. O. PR 62

61 Statistical Simulation 63

62 Windkessel model 64

63 Age Sleep Setting Disease Medication Respiration Body position Physical activity Heart Rate Volume of the blood Viscosity of the blood Compliance / elasticity Blood vessel length Vessel diameter CO PR OR OR Emotional stimuli Nutritional factors Genetic predisposition 65

64 Measurement Techniques 66

65 Amplification Phenomena Blood Flow, Blood Pressure, and Resistance 67

66 Regulation Regulation & homeostasis Baroreflexes Baroreceptor Autonomic Nervous system Sympathetics Parasympathetics 68

67 Methods ABPM HBPM Out of office Clinic BP In office 69

68 Bland and Altman analysis 70

69 Hypertensive Crisis Stage 2 Elevated Stage 1 Normal Hypotensive 71

70 72