Guided Studies Flashcards
Identify some general principles of presrcibing on the hospital drug kardex.
- All patients should have one (even if not currently on any medication, should still contain any drug allergies)
- All drugs to be administered should be prescribed, including oxygen and complementary medicines. (if emergency, can prescribe after use it)
- Only registered medical, dental and non-medical prescribers can prescribe “prescribe-only” drugs
- In English, not latin
- In BLOCK CAPITALS
- General drug name rather than brand name (unless insulin, combination drugs)
- 24 hour clock used for time of administration
- Start date and signature required
- Once patient leaves, kardex put on patient records
Why is it important than the signature of the prescriber is included ?
So potential queries can be directed to the right person
Identify acceptable abbreviations to be used for routes of admin in a drug kardex.
Intravenous = IV Sublingual = SL Nasogastric = NG Per vagina = PV Per rectum = PR Topical = TOP Intramuscular = IM Subcutaneous = SC Inhalation = INH Oral NOT shortened (could be interpreted as a zero)
Identify acceptable abbreviations to be used for doses in a drug kardex.
mg
g
Micro grams and Nano grams spelled out
Units spelled out
.5 or 0.5 ?
0.5
1,000 or 1000 ? Why ?
1000 because , can be confused with decimal point
500 mg or 0.5 g ?
100micrograms or 0.1 mg ?
0.1 microgram or 100 nanograms ?
500 mg because quantities less than 1 g should be written in mg
100 micrograms because quantities less than 1 mg should be written in microgram
100 nanograms because quantities less than 1 microgram should be written in nanograms
Give examples of controlled drugs. How is prescription on kardex performed for these drugs ?
Oxycodone, morphine, Temazepam
CDs are prescribed on the hospital kardex the same way as other drugs. Stored in a specific locked cupboard on the ward, and a register is held and updated whenever a CD is taken out of the cupboard, signed by 2 health professionals before administration to the patient.
On the discharge prescription (or GP prescription) a pharmacist is not allowed to dispense a CD unless all the information required by law is given on the prescription.
What information must be on hospital discharge or GP prescriptions
involving controlled drugs ?
- Name + address of patient
- Name + form + dose + administration + strength of drug
- Total quantity supplied in letters and numbers
- Signature and date by prescriber
What does NKDA stand for ?
No known drug allergies
If the patient has no allergy should you leave the allergies box blank ?
No, write NKDA
Define “non-administration codes”.
Abbreviations used when the prescribed drug was not able to be given (e.g. patient refused, patient unavailable, nausea and vomiting)
Which type of drugs are once only prescriptions usually for ?
Analgesics, pre or post-operative drugs,
and single doses of antibiotics
What is another name for prescription only medicines ?
Stat doses
What type of drugs are as required prescriptions for ?
Analgesics, laxatives and antiemetics (max dose must be specified)
How is warfarin prescribed on the cardex ?
Should be in the anticoagulant/warfarin chart + in the main kardex (administration times etc. should be done on the anticoagulant/warfarin chart)
Identify the main features of transverse sections of cardiac muscle.
- dotted appearance of fibres. Each ‘dot’ is a myofibril
- fibres are narrower than those of striated voluntary muscle
- the nuclei lie in a central position, but the plane of the section does not always pass through the nucleus
- delicate connective tissue (endomysium) supports the rich capillary bed surrounding the muscle fibres
Identify the main features of longitudinal sections of cardiac muscle.
- there is extensive branching of the muscle fibres (not seen in striated voluntary
muscle, except in the tongue) - faint cross striations similar to those of striated muscle
- intercalated discs which are thin lines passing at intervals across the thickness of the muscle fibres – some straight and some in step-wise manner. These discs are unique
to cardiac muscle - endomysium and blood capillaries in the slit-like spaces between the fibres
- the nuclei are oval
Identify the main features of transverse sections of smooth muscle.
-Individual cells vary in diameter depending on their location within the cell. Cross-sections through the middle of cells have centrally located nuclei, usually surrounded by an unstained region.
Identify the main features of longitudinal sections of smooth muscle.
- Relaxed: the nuclei are elongated with rounded ends.
- Contracted: the nuclei spiral, kink, or twist. The cytoplasm is pink, non-striated and with little detail.
Identify the main features of transverse sections of skeletal muscle.
Polygonal cross-sections (50 to 150 µm in diameter) with nuclei at the periphery.
Identify the main features of longitudinal sections of skeletal muscle.
Cells can vary in length from a few millimeters to almost a meter.
-Myofibrils: the cytoplasm is filled with myofibrils that extend the entire length of the cell. Individual myofibrils are only seen where they are slightly separated.
-Sarcomeres: myofibrils show an alternating series of striations due to the repeating sarcomeres.
A band - the main dark band
I band - the main light band
H band - thin light band in the middle of the A band
Z band - thin dark line in the middle of the I band
Complete the following for cardiac muscle:
- Location(s) in the body
- Cell shape and appearance
- Connective tissue components
- Are there myofibrils and are they arranged in sarcomeres?
- Are there T-tubules? Where are they?
- Is there an elaborate SR?
- Are there gap junctions between the cells?
- Do the cells exhibit individual neuromuscular junctions?
- How is contraction regulated?
- What is the source of the Ca2+ for contraction?
- What does Ca2+ interact with?
- Is there a pacemaker?
- How fast is contraction?
- What is the muscle’s response to stretch?
- Is the muscle respiring aerobically or anaerobically or both?
- Location(s) in the body: “muscular wall of the heart (i.e. myocardium). Some cardiac muscle is also present in the walls of the aorta, pulmonary vein, and superior vena cava”
- Connective tissue components: “epimysium, the sheath of connective tissue that surrounds muscles; perimysium, which is associated with groups of cells; and endomysium, which surrounds and interconnects individual muscle cells.”
- Are there myofibrils and are they arranged in sarcomeres? Yes and yes
-Are there T-tubules? Where are they?
Yes, run from the surface to the cell’s interior (“invaginations of external membrane of muscle cells”)
- Is there an elaborate SR? Yes
- Are there gap junctions between the cells? Yes (as part of intercalated discs)
- Do the cells exhibit individual neuromuscular junctions? No
- How is contraction regulated? By intracellular Calcium
- What is the source of the Ca2+ for contraction? Mainly Calcium from SR (but also some from extracellular)
- What does Ca2+ interact with? Extracellular calcium enters cell through DHPR, in T-tubule membrane, binds RYR, opens it, and causes release of more calcium.
- Is there a pacemaker? Yes
- How fast is contraction? Quick contractions
-What is the muscle’s response to stretch?
Increased contraction
-Is the muscle respiring aerobically or anaerobically or both? Mainly aerobically (can be anaerobic during “ brief periods of oxygen deprivation”)
Describe the microscopic appearance of cardiac muscle. Draw it.
Braching and anastomosing shorter fibers with transverse striations running parallel and connected end to end by complex junctions (intercalated discs). Single, centrally located nucleus.
Refer to “Clinically Oriented Anatomy”
Describe the microscopic appearance of smooth muscle. Draw it.
Single, or agglomerated. Small, spindle-shaped fibers without striations. Single central nucleus.
Refer to “Clinically Oriented Anatomy”
Describe the microscopic appearance of skeletal muscle. Draw it.
Large, very long unbranched cylindrical fibers with transverse striations arranged in parallel bundles. Multiple, peripherally located nuclei.
Refer to “Clinically Oriented Anatomy”
List the three major types of blood vessels .
Arteries
Veins
Capillaries
Describe (with the aid of a diagram) the basic composition of the wall of a blood
vessel.
-Tunica intima: contains endothelium (continuation of the endocardial lining of the heart) which forms a slick surface that minimizes friction as blood moves through the lumen. In vessels larger than 1 mm in diameter, a subendothelial layer of loose connective tissue (a basement membrane) supports the endothelium.
-Tunica media: mostly circularly arranged smooth muscle cells (where vasodilation and contraction can occur) and sheets of elastin.
Generally, the tunica media is the bulkiest layer in arteries.
-Tunica externa/adventitia: composed largely of loosely woven collagen fibers that protect and reinforce the vessel, and anchor it to surrounding structures. Infiltrated with nerve fibers, lymphatic vessels, and, in larger veins, a network of elastin fibers. In larger vessels, the tunica externa contains the vasa vasorum (nourish the more external tissues of the blood vessel wall). The innermost or luminal portion of the vessel obtains its nutrients directly from blood in the lumen.
Given that the more external tissues of blood vessel walls are nourished by vasa vasorum contained in the tunica externa, where do the innermost/luminal parts get their blood supply from ?
Directly from the lumen
Describe (with the aid of a diagram) the wall of an elastic (=conducting) artery, linking its structure with its function.
- Thick-walled arteries near the heart (e.g. aorta and its major branches)
- Largest in diameter, ranging from 2.5 cm to 1 cm, and the most elastic
- They contain more elastin than any other vessel type. It is present in all three tunics, but the tunica media contains the most. There the elastin constructs concentric “holey” laminae (sheets) of elastic connective tissue that look like slices of Swiss cheese interspersed between the layers of smooth muscle cells. The abundant elastin enables these arteries to withstand and smooth out large pressure fluctuations by expanding when the heart forces blood into them, and then recoiling to propel blood onward into the circulation when the heart relaxes.
- Elastic arteries also contain substantial amounts of smooth muscle, but they are relatively inactive in vasoconstriction.
- The elastic arteries expand and recoil passively to accommodate changes in blood volume so blood flows continuously rather than starting and stopping with the pulsating rhythm of the heartbeat.
What are the implications if elastic/conducting blood vessels become hard and unyielding (e.g. atherosclerosis) ?
Blood flows more intermittently. Also, without the pressure-smoothing effect of the elastic arteries, the walls of arteries throughout the body experience higher pressures. Battered by high pressures, the arteries eventually weaken and may balloon out or even burst.
Recognise elastic artery histology slides.
Refer to Google.
Describe (with the aid of a diagram) the wall of an muscular (=distributing) artery, linking its structure with its function.
- Deliver blood to specific body organs
- Their internal diameter ranges from that of a little finger (1 cm) to that of a pencil lead (about 0.3 mm).
- Proportionately, they have the thickest media of all vessels. Their tunica media contains relatively more smooth muscle and less elastic tissue than do elastic arteries ( Table 19.1 ); therefore, they are more active in vasoconstriction and less distensible.
- In muscular arteries, however, there is an elastic lamina on each face of the tunica media.
Recognise muscular artery histology slides.
Refer to Google.
Describe the wall of arterioles, linking its structure with its function.
- Lumen diameter ranging from 0.3 mm down to 10 μm.
- Larger arterioles have all three tunics, but their tunica media is chiefly smooth muscle with a few scattered elastic fibers.
- Smaller arterioles, which lead into the capillary beds, are little more than a single layer of smooth muscle cells spiraling around the endothelial lining.
- Minute-to-minute blood flow into the capillary beds is determined by arteriole diameter, which varies depending whether they constrict (the tissues served are largely bypassed) or dilate (blood flow into the local capillaries increases dramatically).
Describe the wall of a venule.
- Lumen diameter ranging from 8 to 100 μm
- The smallest venules, the postcapillary venules, consist entirely of endothelium around which a few pericytes congregate. They are extremely porous (more like capillaries than veins in this way), and fluid and white blood cells move easily from the bloodstream through their walls.
- The larger venules have one or two layers of smooth muscle cells (a scanty tunica media) and thin externa as well.
Recognise arteriole and venule histology slides.
Refer to Google.
Clinically, what is the significance of the porous nature of venules ?
In inflammation, adhesion of white blood cells to the postcapillary venule endothelium occurs, followed by their migration through the wall into the inflamed tissue.
Describe the walls of a vein, linking its function with its structure.
- Veins usually have three distinct tunics, but their walls are always thinner (because the blood pressure in veins is low so no danger of bursting) and their lumens larger than those of corresponding arteries
- Consequently, in the view seen in routine histological preparations, veins are usually collapsed and their lumens appear slitlike.
- There is relatively little smooth muscle or elastin in the tunica media, which is poorly developed and tends to be thin even in the largest veins.
- The tunica externa is the heaviest wall layer. Consisting of thick longitudinal bundles of collagen fibers and elastic networks, it is often several times thicker than the tunica media. In the largest veins–the venae cavae-the tunica externa is further thickened by longitudinal bands of smooth muscle.
- With their large lumens and thin walls, veins can accommodate a fairly large blood volume (i.e. capacitance vessels and blood reservoirs)
- The low-pressure condition demands some adaptations to ensure that blood is returned to the heart at the same rate it was pumped into the circulation. The large-diameter lumens of veins (which offer relatively little resistance to blood flow) are one structural adaptation. Another is valves that prevent blood from flowing backward.
- Venous valves are formed from folds of the tunica interna. Venous valves are most abundant in the veins of the limbs, where the upward flow of blood is opposed by gravity. They are absent in veins of the ventral body cavity.
Recognise a vein histology slide.
Refer to Google.
Recognise the tunia intima, media and adventita on a histology slide.
Refer to Google.
What is so special about the structure of coronary and dural sinuses ?
- Venous sinuses, such as the coronary sinus of the heart and the dural sinuses of the brain, are highly specialized, flattened veins with extremely thin walls composed only of endothelium. They are supported by the tissues that surround them, rather than by any additional tunics.
- The dural sinuses, which receive cerebrospinal fluid and blood draining from the brain, are reinforced by the tough dura mater that covers the brain surface.
Identify possible reasons to use a central line.
• Measurement of central venous pressure (CVP)
• Administration of drugs or products that would damage smaller caliber veins such as
chemotherapy or parental nutrition
• Need to obtain venous access in a patient whose peripheral veins are shut down e.g.
a patient with shock
• Administration of high flow fluids
• Ease of administration of products in a patient likely to need intravenous access for
several days e.g. post major abdominal surgery
What are the most common sites for central line insertion ?
• Internal jugular vein (usually on the right)
• Subclavian vein (usually on the right)
The femoral vein and external jugular vein can also be used but less commonly
Explain the process of inserting a central line.
1) Central lines are placed with the patient lying down and facing away from the site of
insertions to aid identification of the vein.
2) Ultrasound should be used to ensure that the needle is placed correctly and not inserted into the internal carotid or subclavian arteries.
3) After the vein has been correctly located a guide wire is passed through the needle into
the vein. The cannula or catheter is then passed over the guide wire into the vein
The guide wire can then be removed.
What is the use of having multi-lumen central lines ?
This allows different fluids and drugs to be given at the same time whilst the CVP is being measured from a different connection.
What do a high and a low CVP indicate respectively ?
High CVP- Right Heart Failure
Low CVP- veinous return to the heart is less than it should be (e.g. due to hypovolaemic shock or dehydration)
Identify complications of central line insertion.
- Puncturing the apex of the lung, superior to the clavicle, resulting in a pneumothorax
- Puncturing a major vessel as well as a lung resulting in a haemothorax
- Accidentally cannulating a large artery
- Damage to the thoracic duct (if playing line on the left)
- Introducing air into the circulation while inserting the line and causing an air embolism
- If inserted under un-sterile conditions, risk of infection to a major blood vessel and into the bloodstream (risk even if sterile conditions)
- Risk of damage to anomalous veinous valves which may result in thrombus formation
Why are most central lines only inserted for as short a time as possible ?
They are uncomfortable for the patient and there is a higher risk of introducing infection into the bloodstream the longer that they are left in position.
What can we use instead of a central line if access is needed for a longer period of time ?
A special kind of cannula can be inserted such as one with a port placed under the skin.
Clearly differentiate the terms hypoxia and hypoxaemia.
-Hypoxaemia = low PO2 or partial pressure of oxygen (PaO2) in the blood
-Hypoxia = oxygen supplies are insufficient
to meet oxygen demands in a particular compartment (e.g. alveolar or tissue hypoxia)
Which is the most sensitive organ to the effects of hypoxia? How might this present?
Brain.
Impaired mental functioning even in healthy participants.
What are the “five vital signs?”
Pulse rate Blood pressure, Temperature Respiratory rate 5th: oxygen saturation by pulse oximetry in all breathless and acutely ill patients
It is recommended that oxygen is prescribed to achieve a “target saturation”. What
targets does the Guideline suggest for:
a. most acutely ill patients?
b. those patients at risk of hypercapnic respiratory failure?
- For most acutely ill patients: 94-98%
- For patients at risk of hypercapnic respiratory failure: 88-92%
Which clinical conditions does the Guideline suggest oxygen therapy is indicated
for despite the absence of low oxygen saturation? Explain why.
♦ Carbon monoxide: apparently ‘normal’ oximetry reading may be produced by carboxyhaemoglobin, so aim at an oxygen saturation of 100%
♦ Cyanide poisoning: leads to histotoxic
hypoxia
Where should the ball of a flow meter device sit to correctly deliver the required
amount of oxygen?
The centre of the ball should be aligned with the appropriate flow rate marking.
