NVQ evidence
Friday, August 18, 2006
tc1 knowledge evidence questions
Record and evaluate an ECG at rest.
1. Describe the basic structure and function of the cardiovascular system i e: heart, the vessels and circulation.
Heart
The heart and circulatory system
The function of the heart is to continuously supply the whole of the body with blood to function properly. Fresh blood brings oxygen and food to the tissues and carries away unwanted carbon dioxide and other waste products.
The blood circulates around your body through a closed system of blood vessels. The heart is the pump, which pumps it around. It has four chambers and a one-way valve system. Each contraction, or heart beat, pumps blood forward into the arteries. The arteries divide off into smaller and smaller branches to supply a microscopic network of capillaries, distributing the blood to every part of your body.
Blood is collected from the capillaries by the veins. The branches of the veins join to form larger veins delivering blood back to your heart. Blood from your veins fills the heart as it relaxes during the interval between each contraction.
This total circulatory system is called the cardiovascular system. It contains about eight pints of blood, which your heart is continuously re-circulating. Each day, your heart beats about 100,000 times and pumps about 5,000 gallons of blood.
The heart is in fact two separate pumps, which work together. The right side of the heart receives dark, deoxygenated blood, which has circulated around your body. It pumps this to your lungs, where it picks up a fresh supply of oxygen and becomes bright red again.
The left heart receives fresh blood from the lungs and pumps it into the arteries, which supply the rest of the body. Each side of the heart has a thin-walled ‘collecting reservoir’ (the atrium) which helps to fill the thick-walled major pump (the ventricle). The heart wall is made of a special sort of muscle called the myocardium.
Like every other living tissue, the myocardium itself needs to be continuously supplied with fresh blood. This supply of blood comes from the coronary arteries.
Vessels
Arteries
- Theses carry blood away from the heart
- They carry oxygenated blood (with the exception of the pulmonary artery)
- They have a pulse
- They are valveless
- They branch into arterioles then into capillaries
Veins
- Theses carry blood to the heart
- They carry de-oxygenated blood (with the exception of the pulmonary veins)
- They have no pulse
- They are valved
- Capillaries branch into venules then veins
Circulation
- This is the name given to the movement of blood through the vascular system
2. Draw a diagram of there conduction system of the art. Briefly described the normal conduction pathway of the heart.
The sinoatrial node (SAN), located within the wall of the right atrium (RA), normally generates electrical impulses that are carried by special conducting tissue to the atrioventricular node (AVN).
Upon reaching the AVN, located between the atria and ventricles, the electrical impulse is relayed down conducting tissue (Bundle of HIS) that branches into pathways that supply the right and left ventricles. These paths are called the right bundle branch (RBBB) and left bundle branch (LBBB) respectively. The left bundle branch further divides into two sub branches (called fascicles).
Electrical impulses generated in the SAN cause the right and left atria to contract first. Depolarization (heart muscle contraction caused by electrical stimulation) occurs nearly simultaneously in the right and left ventricles 1-2 tenths of a second after atrial depolarization. The entire sequence of depolarization, from beginning to end (for one heart beat), takes 2-3 tenths of a second.
All heart cells, muscle and conducting tissue, are capable of generating electrical impulses that can trigger the heart to beat. Under normal circumstances all parts of the heart conducting system can conduct over 140-200 signals (and corresponding heart beats) per minute.
The SAN is known as the "heart's pacemaker" because electrical impulses are normally generated here. At rest the SAN usually produces 60-70 signals a minute. It is the SAN that increases its' rate due to stimuli such as exercise, stimulant drugs, or fever.
Should the SAN fail to produce impulses the AVN can take over. The resting rate of the AVN is slower, generating 40-60 beats a minute. The AVN and remaining parts of the conducting system are less capable of increasing heart rate due to stimuli previously mentioned than the SAN.
The Bundle of HIS can generate 30-40 signals a minute. Ventricular muscle cells may generate 20-30 signals a minute.
Heart rates below 35-40 beats a minute for a prolonged period usually cause problems due to not enough blood flow to vital organs.
Problems with signal conduction, due to disease or abnormalities of the conducting system, can occur anyplace along the heart's conduction pathway. Abnormally conducted signals , resulting in alterations of the heart's normal beating, are called arrhythmias or dysrrythmia.
By analyzing an EKG a doctor is often able to tell if there are problems with specific parts of the conducting system or if certain areas of heart muscle may be injured.
3. Answered within trust skills pack
4. Answered within trust skills pack
5. Briefly describe some common disturbances of heart rhythm and their causes.
Disturbances of heart rhythm | Causes |
Ventricular Ectopic beats | These are usually one off beats that do not resemble normal sinus rhythm. They are quite normal in most people and happen randomly in most individuals and can be quite harmless. However, if they increase in frequency they can cause problems. If ectopic beats constitute every other beat then the individual is said to be bigeminy. If the rhythm is sinus-sinus-ectopic the rhythm is said to be trigeminy |
Atrial fibrillation | This is where the muscle of the atria does not contract at the same time. It can be of normal speed, fast or paroxysmal (ie, comes and goes) |
Atrial flutter | This is where impulses generated in the Sino-atrial node, which can be as many as three hundred a minute, are not picked up by the atria. It is characterised by numerous p-waves which are not followed by qrst complex. |
Ventrical Fibrillation | This is where the ventricular muscle does not contract in sympathy. This means that the whole heat is ineffective and is not able to pump blood around the body and the individual is said to be in cardiac arrest. Sinus rhythm can be re-established by electrical defibrillation. |
Asystole | This means that there is no electrical activity in the heart thus no muscular contraction, thus no blood circulating. This is what happens when an individual dies. However, in some instances, it can be reversed chemically. |
6. What do the electrodes of the ECG record?
They record the electrical activity of the heart which shows cardiac rhythm and rate.
7. Very briefly, what is the significance of the grid of the ECG paper?
On a standard ECG, each 1mm square is equivalent to one millivolt. This can be used to used as a bench mark by which changes can be calculated.
8. Ventricular ectopic beats can occur in healthy people when they are associated with an excess of tea, coffee or alcohol-true or false.
True
9. Patience ECG tracing shows ventricular fibrillation-why should this give you cause for concern?
See 9
10. You observe the abnormal rhythm of "asytole"-what does this signify?
See 9
11. Answered within trust skills pack
12. Answered within trust skills pack
13. How can we avoid any around almost recordings/readings?
- As the client to sit as still as possible
- Ensure that all leads are in the correct anatomical places
- Ensure that all leads are connect to the correct electrodes
14. Answered within trust skills pack
15. Answered within trust skills pack
16. A) identify some anxieties that a patient might express when informed that she/he will need an ECG.
How would you deal with this?
Anxiety | How to deal with this |
Is it going to hurt? | No, it is not. |
Don’t you put it on my head? | This is when individuals confuse this procedure with ECT (electro-convulsive therapy). It is very important that individuals are informed that an ECG (electrocardiogram). |
Will I get a shock? | Individuals should be informed that this procedure reads electricity |
Do I have to lie down? | For best results, individuals should be lying down. However, if there is a problem with an individual lying down, for example, due to respiratory problems, then it is acceptable for clients not be be lying down and if this is the case, then this must be recorded on the ECG when recorded. |
16. B) consider a patient from a different control background. What would you do if a patient refused to have an ECG, for whatever reason?
Individuals may not wish to have a member of the opposite sex recording an ECG. If this is the case, then it is very important that this is undertaken.
17. If there ECG print-out was poorly printed, what adjustments would you consider to rectify this?
- Try using the filter and if so, record that this was the case on the ECG
- Ensure that all stickers are stuck down securely
- If necessary, replace stickers. If the reading is very poor, then relocating the limb leads on the shoulders and abdomen is acceptable but again this must be recorded on the ECG once recorded
18. You've just taken an ECG and identify some abnormality. What to do next?
- Ask the individual if they are experiencing any pain
- Alert the Registered Nurse in charge
- Take the ECG to a doctor as soon as possible
- Ensure that all relevant information is recorded on the ECG and passed onto the Doctor and the Registered Nurse
- Record the following on the ECG
- Client name and ID number as well as their age
- If the filter was on
- If there was any pain or discomfort
- If so, whereabouts it was
- How many out of ten (0=no pain. 10=worst pain ever) if the client is able to. If the client is not able to able to report pain, ie if they are unconscious or unable to speak, then this should be recorded also.
19. What is the effect of the Digoxin on the ECG?
It slows and strenghthens the heart beat so that means that beats are further apart and the distance between q and r waves are further apart.
20. What should be done before the ECG recording is filed away?
It should be have all the information recorded in 18
Plus it should be signed by a Doctor
21. How would you care for the ECG machine once you have finished with it?
The recording on an ECG is part of emergency care and sometimes needs to be undertaken with some degree of haste. If an ECG machine is not put away in a position where it is not ready for an immediate use, it can be life threatening.
When putting away an ECG machine:-
- Ensure the machine is working properly. If it is not, then this fact should be reported as soon as possible.
- Ensure there is sufficient paper in the machine or available for the next tracing.
- The electrodes are not tangled and are easily available
- The electrodes are not able to become caught on other things
- Ensure that the machine is plugged in so it can re-charge
22. How and why does an ECG recording differ in a child?
Essentially there are no differences between the recording of an ECG in a child than there is with an adult.
There are two main factors to consider:-
- Due to the smaller anatomy of a child, it may be necessary to cut stickers in half when sticking them on the individuals chest.
- The child may not be able to lie still for extended periods, if at all. This may be slightly alleviated by placing the stickers on the shoulders and abdomen which needs to be recorded on the tracing.
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