SCRIPT Questions Flashcards
What is the difference between antimicrobials and antibacterials?
Antimicrobials - act against all microbial organisms - bacteria, viruses, parasites and fungi.
What are examples of bacteriostatic ABs?
Clarithromycin
Doxycycline
What are examples of bactericidal antimicrobial agents?
Phenoxymethylpenicillin
Ciprofloxacine
Metronidazole
Vancomycin
Gentamycin
When can IV antimicrobials be switched to the oral route?
48-72 hours if P has improved clinically and can tolerate oral meds.
When should antimicrobials be reviewed?
48 hours after starting
- change the route?
- change the antibacterial?
- continue treatment?
- outpatient therapy?
Do you need to check serum gentamicin after the initial dose?
Not after one dose - unless there is a plan to give further doses.
Should check be checked x2 per week (more in renal impairment).
Which is the most appropriate AB to follow a gentamicin dose?
Ciprofloxacin
What is the risk of ciprofloxacin?
It can put elderly Ps at risk of contracting C Diff
In what situation should you start antimicrobials?
When there is clear evidence of infection.
If you identify Red Flag Sepsis or septic shock or life threatening infections, when should you start antimicrobials?
Within the hour.
What is the name of the PHE toolkit towards the use of antimicrobials in hospitals?
Start SMART then FOCUS
What is the difference between gram negative and gram positive organisms?
Gram negative have a thinner cell wall - made of less peptidoglycan and more LPS.
What type of bacteria is E coli?
Gram negative
What type of bacteria is Staph aureus?
Gram positive
Does Vancomycin have activity against G -ve, G +ve or both?
G +ve only
What are the three main antibacterial targets in bacteria?
Cell wall & membrane
Protein synthesis inhibition
DNA/RNA inhibition
Which type of ABs inhibit cell wall formation = rapid death of the organism?
Βeta-lactams
Which ABs inhibit a different stage of cell wall formation than β lactams and, when given in high concentrations, cause cell death?
Glycopeptide antibacterials
How do ABs prevent protein synthesis?
Bind to bacterial ribosomes and interfere with their function.
Which types of ABs prevent protein synthesis?
Macrolides (e.g. clarithromycin)
Tetracyclines (e.g. doxycycline)How
Aminoglycosides (e.g. gentamicin)
How do quinolones work?
They interfere with DNA synthesis (e.g. ciprofloxacin)
How does Metronidazole work?
Damages bacterial DNAW
Which types of bacteria does metronidazole work against?
Anaerobic bacteria
How does trimethoprim work?
Interferes with bacterial folate metabolism, resulting in a lack of analogues for DNA synthesis
How does daptomycin work?
It binds to bacterial membranes, leading to depolarisation of the membrane - causes rapid inhibition of protein, DNA & RNA synthesis = cell death
Name 4 classes of ABs which work against bacterial cell walls?
Carbapenems
Cephalosporins
Glycopeptides
Penicillins
Name 3 classes of ABs which work against bacterial protein synthesis?
Aminoglycosides
Macrolides
Tetracyclines
Why are G -ve organisms harder to destroy than G +ve ones?
They have a tough and relatively impermeable outer membrane, which restricts the passage of molecules through it = degree of protection. This is absent in G +ves.
How do the following work to convey defences against ABs:
- Efflux pumps
- Antibacterial-modifying enzymes
- Mutations
Efflux pumps = pump antibacterials back out of the cell before they reach the target site.
AB-modifying enzymes = destroy the AB before it reaches its target
Mutations = in the target side prevent an BA binding
Give an example of a bacterial which has an adapted efflux pump for increased resistance?
Pseudomonas aeruginosa
Give an example of a antibacterial-modifying enzyme?
Βeta-lactamase
Aminoglycoside-modifying enzymes
Give an example of a bacteria which has undergone mutation to prevent the AB from binding to it?
MRSA
What should you use when you prescribe ABs for reference?
Local guidelines
- take into account local resistance
- limit inappropriate use of broad-spectrum agents
- ensures adequate supply in the hospitals
- promotes cost-effectiveness
Why do we treat infection empirically?
Because you can’t know for sure which bacterium is causing the illness - therefore you use experience to determine which is the most likely cause and treat that first.
What is the difference between empirical treatment and directed therapy?
Empirical treatment = when you use best educated guest to target the cause
Directed therapy - when you have identified the cause before you treat
What is the possible disadvantage to using broad-spectrum ABs?
Indiscriminate use can result in adverse effects such as the development of multi-drug resistant strains and C-Diff.
What is the difference between
- susceptible
- susceptible at increased exposure
and
- resistant
organisms?
Susceptible = good likelihood of AB being successful at standard dosing
Susceptible at increased exposure = likely that the AB will be successful if a higher dosing regimen is used
Resistant = likelihood of failure if the AB is used at any dose to treat the infection
What information should you give microbiology about a patient?
- Previous colonisation and/or infection of organisms
- Any known allergies
- Any recent hospitalisation
- Any recent procedures or surgery
- Any recent travel or relevant social Hx
- Any obvious source of current infection
What do you need to document on the chart when prescribing ABs?
Indication for them
Intended route
Duration - inc stop date. Specify a review date as well.
Any intended change in route
What is the CURB-65 score used for?
Estimating mortality of pneumonia to decide whether to treat as inpatient or outpatient
Which infection is strongly associated with Co-Amoxiclav and which population are at greatest risk of developing the disease?
C Diff
Older patients
How should you treat a C Diff infection?
Stool cultures
Stop possible ABs which are causing it
If ABs still needed - use a narrow spectre
Empirical metronidazole should be started whilst awaiting stool culture
Exclude colitis & TMC if there is abdominal pain and pyrexia
Assess for sepsis
What is the downside of a
- subtherapeutic dose
- supra therapeutic dose?
Subtherapeutic = may not adequately treat infection - causing P’s deterioration
Supratherapeutic = can cause nausea & diarrhoea, renal or hepatic impairment.
Why does gentamicin need to take into account lean body weight and renal function when calculating the dose?
To avoid toxicity
What can excessive IV vancomycin cause?
Nephrotoxicity
If AB is not even, what is the potential consequence?
It can cause a supra therapeutic concentration - increasing the risk of toxic effects.
Can also cause a sub-therapeutic concentration.
How can you determine whether to give oral or IV Abs?
If mild infection - can normally give oral if P can tolerate.
If systemic infection - IV required initially to ensure adequate drug concentration is distributed in the tissues.
Exception - if there are deep infections - long courses of IV ABs may be needed.
If the drug has good bioavailability when taken (e.g. levofloxacin) - may not need to use the IV route
What examples of deep infections can you think of?
Infective endocarditis
Osteomyelitis
If ABs are given for too long - what can be the consequences?
Nausea
AB associated diarrhoea
C Diff
What is de-escalation treatment?
When you give a strong IV AB initially and then when the P is stable, you de-escalate the therapy by
- Stopping the AB
- Switching from IV to oral route
- Change the AB
- Continue and review again in 72 hours
- Refer to outpatient parenteral therapy
Which illnesses are mostly self-limiting that do not require AB therapy?
Acute cough
Acute otitis media
Acute sinusitis
Acute sore throat
What is delayed AB prescribing?
Used in the management of conditions which are usually self limiting - can give P a prescription and tell them to cash it only if they get worse.
Which guidelines are used to determine if a patient with a sore throat needs ABs?
FeverPAIN score
When should ABs be prescribed for sore throats?
P has systemic symptoms
Signs and symptoms of a more serious illness
At high risk of serious complications (e.g. valvular heart disease, immunocompromised)
What can you recommend to a P who isn’t given ABs for a sore throat?
Analgesia = paracetamol / ibuprofen
Salt water gargling
Medicated anaesthetic sprays
Maintain adequate fluids
Would you give co-amoxiclav together with trimethoprim for a possibly UTI and chest infection?
Wouldn’t need to give the trimethoprim as the Co-amox is broad spectrum and would be active against most of the organisms which cause UTIs.
Are urine dipsticks reliable diagnostics for catheter related UTIs?
No - catheters are quickly colonised with bacteria - and the dipstick will detect their presence (after 1 month almost all Ps with a long term catheter will have bacteriuria)
When should ABs be prescribed for UTIs in Ps with long term catheters?
What should you do in these cases?
When they have symptoms of a UTI.
Need to remove the catheter if possible and send urine sample of cultures and sensitivity.
How can you get restricted ABs prescribed?
Speak to senior member of the team and then discuss with microbiology who can advise.
If a patient needs an AB - when should the first dose be given?
As soon as possible - and then staggered so the next few doses come into line with the recommended dosing interval to prevent uneven distribution of dosing.
Out of the following which need to be taken with food, on an empty stomach or it doesn’t matter?
- Phenoxymethylpenicillin
- Metronidazole
- Nitrofurantoin
- Amoxicillin
- Trimethoprim
Phenoxymethylpenicillin = empty stomach
Metronidazole & Nitrofurantoin = just after food
Amoxicillin and Trimethoprim = either before or after food
Which dose units are permitted to be abbreviated on a drug chart?
Grams and Milligrams
Is it a legal requirement that the form (e.g. tablets) of the drug be stated on a prescription?
Yes
Which guidance covers authorisation of medicines for human use in the UK?
Human Medicines Regulations 2012
What does NMP, SP and IP mean in terms of staff?
NMP = non-medical prescriber
SP = supplementary prescriber
IP = independent prescriber
What is a PSD? When can you verbally use them?
Patient Specific Direction
Used in emergency situations to administer a medication to a named patient and this is then retrospectively documented.
Inpatient drug charts are patient specific directions = effectively an order to administer to a named patient.
What does TTO and TTA stand for?
Acronyms for discharge summaries - TTO = to take out, TTA = to take away
For what duration should you prescribe drugs post hospital release?
Varies but on TTOs usually min of 14 days is recommended
Can a computer generated signature be used on a FP10 prescription?
No - must be handwritten
When is it a legal requirement that the patient’s age is stated on the prescription?
When they are under 12
Over 12 - is good practice but not a legal requirement
Is it a legal requirement for a date of birth to be stated on an inpatient drug chart?
No - but good practice to do so to help verify patient details.
Not a legal requirement because the drug chart is a patient specific direction - so is an order for administration, not a legal prescription
What are the legal requirements of information that needs to be included on a prescription?
Age if under 12
Patient details - name, address & NHS number
Signature of Prescriber
Today’s Date
Name and address of prescriber - can include GMC number
Dose
Form of preparation (tablets, capsules, oral liquid) - even if one form is available
Strength
Total quantity of the number of dosage units in both words and figures
How long are prescriptions valid for?
For 6 months from issue
Which acts classifies controlled drugs?
Misuse of Drugs Act 1971 (Class A - C)
Which act defines who is authorised to supply and posses controlled drugs?
Misuse of Drugs Regulations 2001
Can F1s prescribe controlled substances?
No
How do you know if a drug is controlled?
Has the symbols CD2 and CD3 next to the drug name in the BNF
What is the total quantity on a prescription?
The number of dosage units - to be given in both words and figures.
For solids - prescribe the number of dosage units in both words and figures.
E.g. Morphine sulfate MR capsules 10mg BD, Supply 14 (fourteen) capsules
For liquids - prescribe the total quantity in both words and figures.
E.g. Morphine sulfate concentrated oral solution 100mg/5ml - 1ml four times a day when required for breakthrough pain. Supply 30 (thirty) mls
When prescribing controlled drugs, how long should you prescribe for?
Do not exceed more than 30 days. Often hospitals will limit to 7-14 days.
What is an unlicensed medicine?
When are they prescribed?
One that does not have a UK marketing authorisation
To fulfil special patient needs where a licensed product is not available
What is off-label prescribing?
Use of a medicine that does have marketing authorisation but is used in terms outside of its licence - e.g. at a difference dose, indication or patient group
What do you need to do when prescribing unlicensed or off-label medicines?
Makes sure that there is no suitable licensed alternatives and that there is a clear evidence base to support use.
Which medicines should be prescribed by brand?
Biologics
When a critical dose is required and different manufacturers have different release mechanisms / bioavailability profiles
What are the two main fluid compartments?
Intracellular and extracellular
Extracellular divide into interstitial and intravascular compartments
What do colloid fluids contain?
Large water insoluble molecules- e.g. carbs or gelatins
How do you work out if a patient needs fluids?
Hx - food and water over past few days. Check any fluid balance charts.
Determine urine output & any other losses.
Check vitals - what has the trend been over the past few days
Check lab results - FBC, U&Es, Creatinine
How much water does the average 70kg man have in his body?
42L
What percentage of water is in the intracellular and extracellular compartments?
65% - intracellular
35% - extracellular (75% interstitial : 25% intravascular)
Which hypothesis states that fluid movement across a wall of a capillary is dependent on hydrostatic and oncotic pressures?
Starling’s hypothesis
What determines the distribution of water between intra and extra cellular compartments?
What is this maintained by?
Extracellular Na ion conc
Maintained by the Na-K ATPase pump
Which ions are at a high conc
- intracellularly?
- extracellularly?
Intracellular - high K and low Na
Extracellular - high Na and low K
What affects oncotic pressure and hydrostatic pressure levels/
Oncotic pressure - determined by the amount of large molecules in the fluid
Hydrostatic pressure - determined by circulatory pressures, tissues pressures (oedema) and mechanical restriction (infection, casts and bandaging).
How much fluid does a healthy adult need a day?
2 - 2.5 litres of fluid
How much insensible losses occur every day?
500-800ml
What levels of water, Na, Cl and K and Glucose are needed each day for routine maintenance?
25-30ml/kg/day water
1 mmol/kg/day of Na, K, and Cl
50-100g /day of glucose
Why is the minimum urine output we aim for in patients?
0.5ml/kg/hour
How much water is lost in normal faeces per day?
100ml
What can increase insensible losses?
Sweating, fever, tachypnoea, open cavity surgery
Which electrolytes are lost via
- sweating
- diarrhoea / inc stoma output
- vomiting
- insensible losses
Sweating = Na loss
Diarrhoea / Stoma = Na, K and HCO3 loss
Vomiting = K, Na and H loss
Insensible losses = pure water loss
What does NaCl 0.9% contain?
154 Na and 154 Cl
What does glucose 5% contain?
50g/L of glucose
What does Hartmann’s contain?
Na (131), Cl (111), K (5), Lactate (29) and Ca (2)
What dos NaCl 0.18% and glucose 4% contain?
Lower Na and Cl than 0.9% - 154 for 0.9 and 30 for 0.18%
40g/L of glucose
What does Gelofusine contain?
154 Na and 124 Cl
Why would a patient be volume depleted but still have a acceptable BP?
How can you verify whether the BP is normal?
BP can be normal due to compensation from peripheral vasoconstriction (peripheral shut down = inc CRT)
Do an orthostatic BP - can be a more sensitive and early indicator of volume loss.
Name some signs of hypovolaemia
Absent / low JVP
Decreased skin turgor (less reliable in Gerrys)
Dry mucous membranes
Low BP
Oliguria / Anuria
Orthostatic hypotension
Peripheral shut down - inc CRT
Shock
Tachycardia (may not be evident in Ps on β blockers)
Name some signs of hypervolemia / fluid overload
Cough +/- white frothy sputum
Fluid accumulation within serosal cavities (pleural, peritoneal)
Hypertension
Peripheral oedema
Pulmonary oedema
Dyspnoea
Raised JVP
S3/S4 heart sounds
Tachycardia
What is the difference between crystalloids and colloids
Crystalloids = solutions of mineral salts
Colloids - contain larger water-insoluble molecules such as carbs or gelatins
What should you take into account when prescribing fluids?
- Type of fluid loss
- Renal function
- Cardiac function
- Concomitant electrolyte abnormalities
Assess Ps
- BP
- CRT
- Fluid balance charts
- Response to straight leg raise
- Skin turgor
- Weight
- Current medications
What are crystalloids divided into?
Isotonic (NaCl 0.9%)
Hypertonic (NaCl 3% mannitol)
Hypotonic (uncommon - NaCl 0.45%)
If you give 1L of NaCl 0.9% - how does it distribute in the fluid compartments?
This is ISOTONIC with plasma
Contains 154mmol/L of Na and Cl
It stays in the extracellular fluid compartment and distributes between compartments - 25% (250ml) will be intravascular and 75% (750ml) will be interstitial
If you give 1L of glucose 5% - how will it distribute between various fluid compartments?
Glucose will enter body cells and undergoes intracellular metabolism
Fluid that remains - 2/3rds will be intracellular, 1/3 will be extracellular - of this only approx 80ml will stay intravascular
What affect do colloids have on the osmotic force?
They increase the osmotic force of the intravascular compartment - therefore driving water to leave the interstitial compartment and enter the intravascular compartment.
What is the drawback of using colloids?
More expensive
Small but established risk of anaphylactoid reactions and anaphylaxis
How does 1L of colloid distribute in the fluid compartment?
It will stay in the intravascular compartment - 1L or colloid will raise the plasma volume by 1L.
What fluid should you give in an emergency situation?
Crystalloids will eventually redistribute but do cause a transient expansion of plasma vol initially before this.
Therefore if you have a depleted shocked patient, give whatever fluid is available to maintain haemodynamic stability.
Cochrane review –> using colloids compared to crystalloids probably makes little or no difference to the number of critically ill people who die.
Is no major difference between the use of colloid and crystalloid.
(Practically - crystalloids are more widely available and considerably cheaper)
What type of fluid should be used for first-line fluid resus and maintenance?
Crystalloids - as they are more widely available and considerably cheaper
What does NICE guidance say about IV fluid therapy in adults in hospital?
Recommends fluid resus using crystalloid that contains Na (131-154 mmol/L) - e.g. NaCl 0.9%.
When can human albumin solution be given?
For patients who have severe sepsis
At what values would the following indicate that the P needs urgent fluid resus?
- Systolic BP
- HR
- CRT
- RR
- NEWS2
- Passive leg raising
- Systolic BP - <100 mmHg
- HR - >90 bpm
- CRT - >2sec or cold peripheries
- RR - >20 breaths per min
- NEWS2 - 5+
- Passive leg raising - suggests fluid responsiveness
What type of shock is the following?
- 750ml lost, 15% vol
Mild tachycardia, slightly delayed cap refill (3s)
Class I shock
What type of shock is the following?
15-30% vol lost (750ml-1500ml)
Cool peripheries, tachycardia, decreased BP, delayed cap refill further (5s secs). Maybe have a catecholamine driven increase in diastolic BP and some anxiety.
Class II shock
What type of shock is the following?
30-40% loss (1500-2000ml) - marked tachycardia and tachypnoea, decreased systolic BP, very narrow pulse pressure, oliguria, low vol pulse, postural drop of 20-30 mmHg, confusion and agitation
Class III shock
What type of shock is the following:
40-50% loss (2000-2500ml) - low GCS or unconsciousness, minimal or no urine output, thready pulse, very tachycardia, very low immeasurable BP, cold skin
Class IV shock
What are the signs of cariogenic shock?
Raised JVP, cardiac arrythmias
What can cause cardiogenic shock?
Ischaemia, heart failure, arrhythmia, cardiomyopathy
What causes obstructive shock?
Physical impedance of the flow of blood - e.g PE and cardiac tamponade.
What test can be done to show whether a P is likely to respond to fluid resus?
Passive leg raise - check HR, BP and stroke volume. Then return them to normal and see if their obs return to baseline pre-test values.
What are the 5 Rs of prescribing IV fluids?
Resuscitation
Routine Maintenance
Replacement
Redistribution
Reassessment
If Ps require IV fluid resus - what is the NICE guidance as to what they should be given?
500ml crystalloid containing Na (130-154 mmol/L)
How do you work out maintenance fluids?
Work out how much fluids they require matched to their body weight, divide by 24 to give the hourly rate.
Based on 25-30 ml/kg/day H2)
1mmol/kg/day Na, Cl and K
50-100g/ day glucose
What conditions should you be aware of when prescribing fluids?
Older age
Frailty
Renal failure
Cardiac failure
Malnourished - risk of refeeding
What are the complications of fluid overload?
Hyponatremia (dilution)
Pulmonary oedema
How can you treat fluid overload?
Stop IV fluids
Furosemide (bolus or IV)
Sublingual nitrate (reduces preload in 5 mins)
IV nitrate (reduces pre and after load - monitor BP)
CPAP
What are the 4 Ds of fluid resuscitation?
Drug - most appropriate fluid selected?
Dose - quantity properly calculated? Rate?
Duration - when to start clearly documented?
De-escalation - when to stop
What is the definition of red flag sepsis?
NEWS of 7 or more
OR
NEWS of 5 or 6 + one of the following
- Lactate >2
- Chemo in last 6w
- Other organ failure evident (e.g. AKI)
- P looks extremely unwell
- Patient is actively deteriorating
When should you assess a P for sepsis?
When they have a NEWS of 5 or more with S&S of infection
When should you not use NEWS2?
In patients under 16
In pregnancy women
The physiological response to illness can be altered in these groups.
What qualifies as an amber flag for sepsis?
NEWS2 of 5-6
OR
NEWS2 1-4 + one of the following:
- Lactate >2mmol/L
- Chemo in last weeks
- Other organ failure evident (e.g. AKI)
- Patient looks extremely unwell
- Patient is actively deteriorating
What should happen in amber sepsis warning?
Send and review bloods
Escalate to senior review within 1 hour
Consider if antimicrobials are needed - administer and plan for escalation within 3 hours
What is the most severe form of sepsis?
Sceptic shock
What is sceptic shock?
Sepsis with persisting hypotension requiring vasopressors to maintain MAP >65mmHg and having a serum lactate >2 despite volume resus.
If the hypotension remains refractory to fluids plus there is a persistent serum lactate >2 - the patient is in sceptic shock
Sepsis + Refractory Hypotension = Septic Shock
What is the mortality rate of septic shock?
50%
What is cryptic shock?
Patients have a high lactate (>2) in the presence of normal blood pressure.
OR
Patients can have sepsis-induced hypotension without a raised blood lactate concentration.
At what respiratory rate would you start to consider sepsis?
> 25 breaths per minute
What is puerperal sepsis?
Sepsis originating from the genital tract (esp uterus)
Why can neutropenic sepsis be difficult to pick up on x-ray?
Neutrophils are needed to make pus - therefore X-ray or wound may be clear even though there is infection due to lack of neutrophils
How do you treat a patient with renal impairment and sepsis?
All patients should receive a first full loading dose of each antimicrobial agent, irrespective of renal function.
Subsequent doses should be then adjusted according to renal function.
When prescribing ABs - which things in the history should you ask about?
Allergies
Recent travel
Recent hospital admission
Resistance and sensitivities
48-72 hours after commencing ABs you should review them. What things should you think about at this point?
Drug - check sensitivities - stop or switch if needed, continue current treatment. Can refer for outpatient parenteral AB therapy.
Dose - monitor renal impairment & whether the sepsis is resolving. Can increase dose/frequency as needed.
How long prior to surgery should you restrict solids and fluids for?
Six hours for solids
Two hours for liquids
What is the rule regarding medicines prior to surgery?
Give medicines with a withdrawal potential (can be given with clear fluids until 2 hours prior to surgery)
Omit medicines that may increase operative risk
Why should you omit ACEIs prior to surgery?
Associated with marked hypotension following induction of anaesthesia
What is CASES used to perioperatively?
To remember to ask certain questions in the surgical hx
C = Contraception - risk of pregnancy and VTE
A = Anticoagulation = risk of bleeding
S = Steriods = risk of Addisons Crisis
E = Ethanol - risk of withdrawal, possible interaction with anaesthetic
S = Smoking - lung disease potential
How far in advance should antiplatelet therapy be stopped prior to surgery?
7 days - although need to weigh up risk of continuation (thrombosis) v. risk of bleeding
When does the contraceptive pill need to be discontinued?
If there is a high risk of thromboembolism
When do you need to think about swapping drugs to the parenteral route?
If the P has GI problems
If they will be starved post-operatively
If the absorption of oral medicines will be affected post-operatively - e.g. diminished BF to the gut, villous atrophy, mucosal ischaemia and diminished motility from postoperative ileus.
What is high glucose concentrations perioperatively associated with?
Increased risk of infection and poorer outcomes. Longer length of stay, increased adverse outcomes.
Therefore need to ensure good control before, during and after surgery to improve outcomes.
When should metformin be omitted prior to surgery?
It should be omitted on the day of the procedure and for the following 48 hours IF
- eGFR is <60ml/min
- if radiocontrast is being used
- if a variable rate insulin infusion (VRIII) is being used
What should happen to a patient’s long-acting insulin if a variable rate infusion insulin is being given?
Long-acting insulin should be continued at 80% of the dose.
Which patients should be given variable rate insulin infusion?
Prolonged periods of starvation (more than one meal missed)
No / unknown post op enteral absorption
HbA1c >69 mmol
T1DM + major surgery
T1DM + not had background insulin
Infection
Most Ps with DM who have emergency surgery
If only one meal is missed, P can often be managed without IV insulin.
What is the difference between managing a P with T1DM and T2 DM in terms of VRIII?
T1DM - P is dependant on exogenous insulin - if starved and no insulin - risk of DKA and dehydration (due to hyperglycaemia -> diuresis). They need VRIII
T2DM - VRIII is only required if blood glucose is poorly controlled or for major/emergency surgery. Treat these as T1DM in perioperative period.
When can you stop VRIII?
When the patient can eat and drink normally without nausea and vomiting.
What should happen to the following drugs prior to surgery?
- Sulphonylureas (gliclazide)
- Pioglitazone
- DPP4 Inhibitors (sitagliptin)
- SGLT-2 Inhibitors (dapagliflozin)
- GLP-1 Receptor antagonists (Liraglutide)
Sulphonylureas - omit on day of surgery
Pioglitazone - take as normal on day of surgery
DPP4 Inhibitors - take as normal on day of surgery
SGLT-2 inhibitors - omit on day and day before surgery
GLP-1 RAs - take as normal on day of surgery
When should DOACs be stopped prior to surgery?
If low bleeding risk - 24 hours prior to surgery
If high bleeding risk - 48 hours prior to surgery
Even more if Ps have renal dysfunction
What is the MOA of Dabigatran? What is its half life?
What is its protein binding?
How is excreted?
When is it CI?
When should it be restarted post surgery?
Is a direct thrombin inhibitor
Half life = 12-14 hours
Poorly protein bound - 80% renally excreted
CI - Ps who have creatinine clearance <30ml/min
Restart 48-72 hours post surgery depending on Ps bleeding risk, haemostats and renal function.
What is the MOA of Rivaroxaban?
What is its half life?
What is its protein binding?
How is excreted?
When should it be restarted post surgery?
Direct Factor Xa inhibitor
Half life = 5-13 hours
Strongly protein binding (90%)
66% renally excreted
Restarted - case by case basis - depending on bleeding risk, haemostasis and P’s renal function.
Minor procedures + low bleeding risk - start within 24 hr
Major procedures - typically 48hr
What is the MOA of Apixaban?
What is its half life?
What is its protein binding?
How is excreted?
When should it be restarted post surgery?
Factor Xa inhibitor
Half life = 12hr
Strongly protein bound (87%)
25% renally excreted
Restart - case by case basis - typically 48-72hr post surgery depending on bleeding risk, haemostasis and renal function.
What is the MOA of Edoxaban?
What is its half life?
What is its protein binding?
How is excreted?
When should it be restarted post surgery?
Factor Xa inhibtor
Half-life = 10-14hr
Protein binding = 55% and 50% renally excreted
Restart - as soon as adequate haemostasis is established
When should vitamin K be stopped prior to surgery?
At least 4-5 days prior to surgery , minimum 24hr for elective surgery or 48hr if operation carries a high bleeding risk.
What is the difference between unfractionated heparin and LMW heparin?
Unfractionated = given as an IV injection or infusion that can be rapidly loaded. Needs monitoring with Activated Clotting Time (ACT) or Activated Partial Thromboplastin Time (APTT).
LMWH - once or twice daily SC injection. In most Ps monitoring is not required.
When should LMWH be stopped prior to surgery?
LMWH must be stopped 24 hours prior to surgery and restated when the risk of bleeding has passed (at least 48hrs)
When should warfarin be stopped prior to surgery?
Warfarin should be stopped 4-5 days prior to the operative day - LMWH should be prescribed until oral anticoagulation can be reinstated postoperatively.
Why should Ps on LT corticosteroids not have their medication discontinued perioperatively?
Underlying condition for which steroids are tx may flare following withdrawal.
HPAA will be suppressed
Stress of surgery may increase the need for steroid replacement markedly - related directly to the degree of surgical insult.
How should patients on steroids be treated prior to surgery?
Should be kept on their oral medication and on the morning of surgery they should received their usual dose.
At induction of surgery they should receive 100mg IV hydrocortisone.
Following the induction dose, they should be initiated on a continuous infusion of hydrocortisone at a rate of 200mg over 24h.
When enteral nutrition is reestablished - the P should take double dose of their usual corticosteroid - which can then be tapered back to their normal dose within 48hr - 1w depending.
Do statins need to be stopped in the perioperative period?
No - no need to omit perioperatively
Should β blockers be stopped perioperatively?
If prescribed for IHD they should not be abruptly stopped as they put the P at high risk of cardiovascular adverse events
Should MAOIs be stopped perioperatively?
They should be stopped 2 weeks before surgery due to risks of hypo and hypertension
Should Lithium be stopped perioperatively?
They are omitted the day before surgery and re-started post-op providing U&Es are normal
When should prophylactic ABs be administered perioperatively?
For some surgeries - if indicated - they should be administered 30-60 mins prior to skin incision to minimise the risk of infection.
What are the risks of the following medications if taken prior to surgery?
Impact on anaesthetic agents:
- Α blockers
- Antispsychotics
- ACEIs & AGTII RAs
- Ca Channel Blockers
- Lithium
- MAOIs
- Tricyclic ADs
Impact on neuromuscular blockers:
- Anticonvulsants
- Aminoglycosides & Vancomycin
- Digitalis glycosides
- Lithium
Impact on anaesthetic agents:
- Α blockers = Hypotensive effect
- Antispsychotics = Hypotension
- ACEIs & AGTII RAs = Severe hypotension
- Ca Channel Blockers = Hypotensive efect and AV delay with verapamil
- Lithium - enhanced muscle relaxants
- MAOIs = stop 2w prior due to risk of hypo and hypertension
- Tricyclic ADs = inc risk of arrhythmias and hypotension
Impact on neuromuscular blockers:
- Anticonvulsants = neuromuscular blocker reduced and shortened - esp chronic phenytoin and carbamazepine
- Aminoglycosides & Vancomycin = neuromuscular blockage prolonged and increased
- Digitalis glycosides = risk of ventricular arrhythmias
- Lithium = effects of neuromuscular blockers enhanced
What is given for VTE prophylaxis postoperatively?
Compression stockings
Perioperative mechanical calf compression
Anticoagulants - LMWH mainstay but can use UFH (esp if prosthetic heart valve)
Which medicines can be given to treat post operative nausea and vomiting?
Antihistamines (cyclizine)
5HT antagonists (ondansetron)
Phenothiazines (prochlorperazine)
Dexamethasone
Oral antiemetics are not always appropriate due to to poor GI absorption postop, or if P is already symptomatic.
What is the MOA of promethazine?
Acts by blocking H1 and muscarinic receptors in the chemoreceptor zone (CTZ).
What is the MOA of ondansetron?
Acts by blocking 5HT receptors in the CTZ and in the gut.
What is the MOA of prochlorperazine?
Dopamine antagonists that acts in the CTZ
What is the MOA of domperidone?
Is a dopamine antagonist at the CTZ and has gastrokinetic effects. Does not cross BBB - less likely to have sedative or dystonic effects.
Which drug can increase the risk of hypotension if prescribed with propofol?
Haloperidol
Which weight do you get when you stand a patient on a set of scales?
Actual Body Weight
How is lean body weight calculated?
By subtracting body fat weight from actual body weight
Which weights would you need for:
- drugs that mainly distribute into water
- drags that mainly distribute into fat
Water = lean or ideal body weight
Fat = actual body weight
Which units can be abbreviated?
Which units need to be written out in full?
Abbreviated = kg, g and mg
Not abbreviated = micrograms, nanogram and units
1mg = ? micrograms
1mg = 1000 micrograms
1 microgram = ? nanograms
1 microgram = 1000 nanograms
What does %w/w mean?
Percentage weight per weight
1% w/w - there is 1g of drug in 100g of product
What does 0.5% w/w hydrocortisone cream contain?
0.5g hydrocortisone in 100g of cream
How much sodium chloride is contained in 0.9% solution - in both g/ml and mg/ml.
0.9g in 100ml
900mg in 100ml or 9mg in 1ml
What does %w/v mean?
The percentage weight of a drug per volume? Used for medicines added to diluent.
How much sodium chloride is there in a 0.9% w/v infusion?
1g per 100ml
therefore 0.9g in 100ml
(equivalent to 900mg in 100ml or 9mg in 1ml)
What does % v/v mean?
Percentage volume per volume
In 1% v/v there is 1ml of drug in 100ml of final product
E.g. 70% v/v of isopropyl alcohol = 70ml of isopropyl alcohol in 100ml of solution
How much glucose is in 5% 500ml?
5% = 5g in 100ml
Therefore 500ml = 5x5 = 25g of glucose
What does 1:1000
and
1:10000 represent in terms of drug concentration?
1g in 1000ml
1g in 10 000ml
If adrenaline 1:1000 is prescribed - how many mg of adrenaline are in 1ml?
1g in 1000ml
0.001g in 1ml
aka - 1mg in 1ml
If adrenaline is 1:200 000 is prescribed - how many micrograms are found in 1ml?
1g in 200,000ml
same as
1000mg in 200 000
1mg in 200ml
same as
1000 micrograms in 200ml
10 micrograms in 2ml
5 micrograms in 1ml
How many pounds in a stone?
14
What is 1lb equivalent to in g?
450g
What is 1 stone equivalent to in kg?
6.35 kg
How many inches in a foot?
12
How should gentamicin be dosed in obese patients?
According to
- Body surface area
- Actual body weight
- Ideal body weight
In obese patients, gentamicin should be dosed according to the patient’s idea body weight.
How old is a person classes as an (a) neonate (b) infant (c) child and (d) adolescent?
A = Up to 1 month
B - Up to 1 year
C - 1-11 years
D - 12-16 years
If 1L over 8 hours is prescribed - what is the hourly rate?
1000/8 = 125ml
