Chapter 3 MI Introduction to Patient Monitoring System

Question 1

What is the purpose of patient monitoring?

Answer 1

To have a quantitative assessment of the patients important physiological variables during critical conditions of his biological functions

Question 2

What are some desired design features of a Patient Monitoring System? (3 examples)

Answer 2

1) Mobility
2) Ease of use
3) Effortless patient data transfer

Question 3

What are the 6 patient monitoring variables?

Answer 3

1) Body Temperature
2) Heart Rate
3) Blood Pressure
4) Respiration Rate
5) Oxygen Saturation
6) ECG

Question 4

What is the normal core temperature range?

Answer 4

36.5 Degree Celsius to 37.5 Degree Celsius

Question 5

Will body temperature increase when waking up, by how much?

Answer 5

Yes, by 0.5 Degree Celsius

Question 6

Does anesthesia lower body temperature, by how much?

Answer 6

Yes, by 1 Degree Celsius

Question 7

What are the 4 modes of body heat loss?

Answer 7

1) Radiation
2) Convection and conduction of air
3) Evaporation of sweat
4) Evaporation of water through breathing

Question 8

What are the 4 Temperature Measurement Methods?

Answer 8

1) Invasive or Non- Invasive
2) Contact or Non Contact
3) Direct or Indirect
(Direct means convert temperature to electricity, while Indirect means curve or algorithm)
4) 1-D and n-D

Question 9

What is an Invasive way to measure temperature?

Answer 9

May require needle-type or a catheter-type (rectum and blood vessel)

Question 10

What is an Semi-Invasive way to measure temperature?

Answer 10

Normal clinical thermometer (through the mouth)

Question 11

What is an Non-Invasive way to measure temperature?

Answer 11

Normal clinical thermometer can be used, including infra-red radiation types (forehead, ear canal)

Question 12

Heart rate measurement can come from which 2 types of reading?

Answer 12

1) ECG reading
2) Pulse rate reading

Question 13

What is the typical range of heart rate measurement?

Answer 13

0 - 250 beats/min

Question 14

What is the normal heart rate range?

Answer 14

60 - 100 BPM

Question 15

What is blood pressure?

Answer 15

It is the force of the body’s blood pushing against the walls of your blood vessel

Question 16

What is systolic pressure?

Answer 16

It is the pressure when your heart contracts

Question 17

What is diastolic pressure?

Answer 17

It is the pressure when your heart rests between beats

Question 18

What is a Healthy BP reading?

Answer 18

120/80 mmHg or lower (millimetres of mercury)

Question 19

Can Diastolic BP change with age?

Answer 19

Yes, diastolic blood pressure can increase with age as a result of stiffening arteries

Question 20

What are the 3 Indirect Methods to measure BP?

Answer 20

1) Auscultatory (using Sound)
2) Oscillometric (using Vibration)
3) Ultrasonic (using Waves)

Question 21

What is auscultatory method?

Answer 21

1) Occlusive cuff is inflated until the pressure is above systolic pressure then slowly bled off
2) When the systolic peaks are higher than the occlusive pressure, the blood spurts under the cuff
3) Audible sounds (Korotkoff sounds) generated by the flow of blood and vibrations of the vessel under the cuff are heard through a stethoscope
4) The manometer pressure at the first detection of the pulse indicates systolic pressure
5) When the sound can no longer be heard, the manometer pressure indicates diastolic pressure
6) This depends on the hearing acuity of the user, as well as a relatively quiet environment

Question 22

What is oscillometric method?

Answer 22

1) Compression cuff is inflated above systolic pressure and slowly deflated
2) Systolic pressure is detected where there is a transition from small amplitude oscillations to increasing cuff-pressure amplitude
3) Algorithmic methods are used to predict diastolic pressure

Question 23

What is ultrasonic method?

Answer 23

1) Compression cuff is placed over the transmitting and receiving crystals (at 8MHz)
2) Opening and closing of blood vessel are detected as the applied pressure is varied

Question 24

What are the 2 Direct Methods to measure BP?

Answer 24

1) Extravascular Sensor (Sensor outside of body)
2) Intravascular Sensor (Sensor inside body usually tip of needle)

Question 25

What is extravascular sensor?

Answer 25

A sensor outside of body (Typically a catheter that is connected to an external pressure sensor; inserted surgically)

Question 26

What is intravascular sensor?

Answer 26

A sensor inside the body, usually tip of needle (The sensor is incorporated into the catheter tip; inserted surgically)

Question 27

What is the technique to obtain heart rate from ECG?

Answer 27

Heart rate meters usually work on the basis of converting each R wave of the ECG into a pulse of fixed amplitude and duration. Afterwards, it will determine the average rate from those pulses.

Question 28

What is the technique to obtain pulse rate from oximeter?

Answer 28

The pulse oximeter typically uses photoelectric method (reflectance or transmittance) to pick up the pulse rate

Question 29

What is Respiration Rate?

Answer 29

It is the number of breaths a person takes in a minute (usually at rest)

Question 30

What is the normal range for Respiration Rate?

Answer 30

12 - 25 breaths per minute

Question 31

What is the 5 Measurement Methods for Respiration Rate?

Answer 31

1) Displacement Method 2) Thermistor Method 3) Impedance Pneumography 4) CO2 Method 5) Apnea Detectors

Question 32

What is Oxygen Saturation?

Answer 32

It is the measurement of how much oxygen is bounded to your blood

Question 33

When/why do we need to know the level of blood oxygen saturation? (5 examples)

Answer 33

1) During or after procedures that uses sedation 2) To see how well lung medicines are working 3) To check a person’s ability to handle increase activity levels 4) To see if ventilator is needed to help to breathe 5) To check if there are moments when breathing stop during sleep

Question 34

How do we measure Oxygen Saturation? (3 examples)

Answer 34

1) Pulse Oximetry (most common way to measure) 2) Skin Reflectance Oximeter 3) Intravascular Oximeter

Question 35

What does P wave represent?

Answer 35

Contraction/Depolarization of the Atria

Question 36

What does the QRS Complex represent?

Answer 36

Contraction/Depolarization of the Ventricles

Question 37

What Does the T wave Represent?

Answer 37

The Relaxation/Repolarization of the Ventricles

Question 38

Where does the repolarization of the atria occur?

Answer 38

During the QRS complex, which masks it on the ECG

Question 39

What are common ECG abnormalities? (5 examples)

Answer 39

1. Second-degree block 2. Atrial fibrillation 3. Ventricular tachycardia 4. Ventricular fibrillation 5. Third-degree block

Question 40

How does Second Degree block look like?

Answer 40

From diagram, 50% of P wave no QRS and 50% of P wave got QRS

Question 41

How does Atrial Fibrillation look like?

Answer 41

From diagram, there is no clear P wave while QRS got more QRS wave

Question 42

How does Ventricular Tachycardia look like?

Answer 42

From diagram, during the S phase of QRS, it will have a very big dip down

Question 43

What Does Ventricular Fibrillation look like?

Answer 43

From diagram, it just looks like noise, no clear wave

Question 44

How Does Third-Degree Block look like?

Answer 44

From diagram, it looks like a flat line but sometimes there is still a small signal

Question 45

How many electrodes are there in ECG? (Chest how much? Limb how much?)

Answer 45

10 Electrodes 6 Chest electrodes 4 Limb electrodes

Question 46

What are the 6 Frontal Leads?

Answer 46

1) I 2) II 3) III 4) aVR (augmented unipolar Vector Right leg) 5) aVL (augmented unipolar Vector Left leg) 6) aVF (augmented unipolar Vector Foot)

Question 47

What are the 6 Transverse Leads?

Answer 47

1) V1 2) V2 3) V3 4) V4 5) V5 6) V6

Question 48

How many of the 12 leads are bipolar and what are they?

Answer 48

3 leads (bipolar) 1) I Lead 2) II Lead 3) III Lead Because no fix reference point

Question 49

Lead I, 2 electrodes start from where and end at where?

Answer 49

Starts From Left Arm (+) ends at Right arm (-)

Question 50

Lead II, 2 electrodes start from where and end at where?

Answer 50

Start from Left Leg (+) to Right Arm (-)

Question 51

Lead III, 2 electrodes start from where and end at where?

Answer 51

Start from Left Leg (+) to Left Arm (-)

Question 52

What is Eindhoven’s Triangle?

Answer 52

The vectors of leads I, II, and III where I - II + III = 0 (Basically, KVL also known as Kirchhoff's Voltage Law)

Question 53

Suggest situations for continuous observation of ECG and heart rate (3 examples)

Answer 53

1. During anesthesia and recovery from anesthesia 2. During danger period following myocardial-infarction 3. During labour

Question 54

In cardiac monitor, briefly describe functions of a) Pre-amplifier b) Isolation circuit c) Amplifier d) ADC e) Alarm indicator

Answer 54

a) Pre-amplifier - amplifies ECG signals and improve signal-to-noise ratio b) Isolation circuit - blocks current from power line c) Amplifier - amplifies ECG signals to appropriate level for recording (include band-pass filter) d) ADC - digitizes ECG signals to facilitate storage, display and transmission e) Alarm - warns of high and low heart rates

Question 55

What are the common artefacts in ECG? (3 examples)

Answer 55

1) Power line interference 2) Baseline shift 3) Muscle tremor

Question 56

How to reduce the effects of power line interference?

Answer 56

Noise rejection circuitry in amplifiers, shielding, earthing

Question 57

How to reduce the effects of baseline shift?

Answer 57

Ensure patient is relaxed and electrodes properly attached with electrode gel

Question 58

How to reduce the effects of muscle tremor?

Answer 58

Can be partially solved by attaching electrodes to chest instead of limbs