Pre-op Flashcards
How long before surgery should a patient have a pre-operative assessment?
2-4 weeks
What classification is used to assess a patient’s airway for potential difficulty in intubation?
Mallampati classification
A general structure of pre-operative history (during pre-op assessment)
- HPC - why did the patient first attended ->what procedure is planned
- PMH - general one, but ask particularly about: CVS, respiratory, endocrine, renal problems
- Extra questions:
- women in reproductive age -> pregnancy?
- Afro-Caribbean origin -> sickle cell anaemia?
Past surgical history: any surgeries before?
- Past anaesthetic history: have they head anaesthetics before -> any issues -> how they were during recovery -> nausea/vomiting?
- Drug history: medication and allergies
- Family History: any adverse reations in surgery? malignant hyperpyrexia/ hypertermia?
Why is it important, in pre-op assessment history to ask about:
- cardiovascular disease
- respiratory disease
- renal disease
- endocrine disease
- cardiovascular disease (include HTN and exercise tolerance) -> as the risk of acute cardiac events is increased during anaesthesia
- respiratory disease -> to plan adequate oxygenation and prevent ischaemic events in peri-operative period
- renal disease:
- surgical complications increased with renal disease-causing: biochemical imbalance, coagulopathy, anaemia
- IV contrast or blood loss may worsen renal problems -> therefore careful planning is needed
- endocrine disease (especially DM and thyroid problems) -> medication requires change in peri-operative period
What (2) examinations should be performed in pre-op assessment?
- General examination -> looking at any obvious pathology in CVS, respiratory, abdominal signs
- Airway assessment -> to predict difficulties with intubation
*area of procedure could be also examined
ASA grading - simple explanation of each score
ASA grade directly co-relates with a grade of post-op complications/ mortality
The choice of pre-op investigations depends on what? (4)
- local guidelines
- seriousness of procedure
- age
- co-morbidities
What blood tests could be done pre-op? And why? (5)
- FBC -> to identify any potential anaemia and thrombocytopaenia -> this needs to be treated before surgery to minimise cardio-vascular compromise
- U&Es -> to assess renal function; this will allow planning if iV fluids would be administrated
- LFTs -> to assess liver metabolism and synthesis -> as may require to adjust dosing
- Clotting screen -> any coagulation problems (e.g. haemophilia, warfarin use) would need to be corrected before the surgery
- Group and Save (G&S) and crossmatch -> to prepare for blood loss and eventual transfusion
What’s the difference between G&S and crossmatch?
G&S -> to define patient’s ABO group and Rh status; it also screens the blood for atypical antibodies
(G&S is recommended if blood loss is not anticipated; done in case if the blood loss would be greater than expected)
Crossmatch -> patient and donor’s blood are physically mixed -> to see if any immune reaction takes place; if it does then the other blood is tried
(crossmatch is done if a blood loss is anticipated; G&S must be done first)
What imaging is often done in pre-op assessment? (4) Justify
- ECG -> done in a person with underlying cardiac problems or if major surgery is planned
it allows to a) identify cardiac pathology b have a baseline picture so we can identify a new onset of post-op cardiac ischaemia)
- ECHO -> it is considered if a) murmur is identified b) HF or its signs and symptoms c) signs and symptoms of cardiac disease
- CXR -> it should not be done routinely, on everyone; do if:
- systemic resp disease and no recent (last one was done >12 months ago) CXR
- significant smoking history
- recent travel to TB endemic area
- new onset of cardio-respiratory signs
- Spirometry -> if a patient has a chronic lung condition
done to assess baseline in case if post-op complications arise
What other tests are done pre-op? (4) justify
- pregnancy test -> women in reproductive age
- urinalysis -> not done pre-op routinely; only if evidence of UTI or glycosuria
- sickle- cell anaemia -> do not do routinely, only if FHx or a person is African/Afro-Carrabiean origin
- MRSA swab -> swabs from nostril + perineum + other sites -> if MRSA is identified, anti-septic body and hair-wash is given + topical ointment applied to the nostril
*it is given pre-op for elective surgery patients (even if the operation would be delayed)
Investigations for day-case patients
- ECG – All patients >70yrs or a history of chest pain, hypertension, or a heart murmur
- LFT’s – Any alcohol intake over the expected amount
- U&E’s – All patients >60yrs, currently taking antihypertensives, history of DM or renal problems, or a urine sample >1+ protein
- Sickle cell test – If Afro Caribbean (and not previously tested)
- CXR – Any recent pneumonia, to discuss with anaesthetist
- TFTs – Patients on thyroxine or having thyroid surgery
- FBC – All patients >60yrs, or history of anaemia, any bleeding disorder, or sickle cell trait
For DM patients, perform a routine HbA1c; if >69mmol then disucss with anaesthetist regarding the need to defer the surgery
What about fluid intake in regards to NBM before most surgeries?
Clear fluids up to 2 hours before
Which medication should be stopped earliest before surgery?
Clopidogrel
How long before the surgery stop HRT/OCP?
4 weeks before
Contraindications to LMWH
- endocrine, neck surgery
- peptic ulcer disease
- previous cerebral haemorrhage
What procedure requires phosphate enema in the morning before the operation?
Left hemicolectomy
What’s RAPRIOP?
It is a mnemonic for pre-op management of a patient
R - reasurrance
A - advice
P- prescription
R - referral
I - investigations
O- Obs
P - patient
Advice regarding fasting before surgery (A in RAPRIOP)
- Stop eating – 6 hours before
- Stop dairy products (including tea and coffee) – 6 hours before
- Stop clear fluids – 2 hours before
Why do we need to fast before surgery?
It is mainly to avoid pulmonary aspiration during peri-operative period
*may cause:
- pneumonitis -> do to very acidic gastric content
- aspiration pneumonia -> due to secondary infection following pneumonitis or aspiration of an infected material
What are 3 categories of pre-operative drug regimes (in regards to P from RAPRIOP)
P - prescriptions
- prescriptions to stop
- prescriptions to alter
- prescriptions to start
*some patient may require bowel preparation and blood productions
What are (4) drugs to stop before surgery and when?
Memonic CHOW
C - clopidogrel -> stop 7 days before surgery (due to bleeding risk)
*Aspirin and other anticoagulants can be carried out - as minimal effect on surgical bleeding
H - hypoglycaemics -> complicated, another flashcard
O - OCP or HRT-> 4 weeks before surgery (due to DVT risk)
W - Warfarin -> stopped 5 days before the surgery and LMWH started instead
What’s the INR target for a patient on Warfarin before surgery?
Need to be INR <1.5 an evening before the surgery
if INR is above the target then may need to supplement the patient with PO vitamin K
What are drugs to alter before surgery (2)?
- Subcutaneous insulin -> may switch to IV variable rate infusion
- Long term steroids -> must continue (risk of Addisonian crisis if not) -> If the patient cannot take these orally, switch to IV
Conversion rate of predniosolone (PO) to hydrocortisone (IV)
conversion rate is 5mg PO prednisolone = 20mg IV hydrocortisone
What considerations should be done pre-op for a patient on long - term steroids?
Surgery -> metabolic insult and trauma -> activation of HPA -> production of corticosteroids
If a patient is on a long- term steroid therapy -> HPA may be suppressed = risk of acute adrenal failure
Management: give a peri-operative stress dose of corticosteroids
(3) drugs that we need to prescribe pre - op
- LMWH -> complete VTE risk assessment on admission, but most of the patient will receive it unless contraindications exist
- TED stockings -> all patients receive below the knee TED stocking (but contraindicated in vascular surgery patients) *also contraindicated in other instances - on different flashcard
- Prophylactic antibiotics -> for patients with orthopaedic, GI, vascular surgeries
General (in simple terms) management of a patient with T1DM pre-surgically
- considerations before surgery
- NBM patient
- post-op
Pt should be put in the morning, at the beginning of the list:
(means they may need to be admitted a night before)
A) Before surgery
- reduce subcutaneous insulin a night before
- omit morning insulin
- commence IV variable insulin infusion pump
B) if a patient is NBM
- give dextrose infusion and check BM every 2 hours
C) Post-op
- continue until the patient is able to eat and drink
- overlap IV infusion stopping with SC insulin regimen
-
Pre-op management of pt with T2DM
- if managed with diet only
- if managed with oral hypoglycaemics
A) If T2DM patient is managed by diet and no med - nothing has to be done
B) Oral hypoglycaemics
- Metformin -> stop on the morning before surgery
- other hypoglycaemics -> stop 24 hours before the surgery
*insulin IV variable infusion rate is then started + 5% dexterose -> managed as T1DM patient
(2) categories of surgeries that require bowel preparation + what to use
- Left hemi-colectomy, sigmoid colectomy, or abdo-peroneal resection: Phosphate enema on the morning of surgery
- Anterior resection: 2 sachets of picolax (laxative) the day before or phosphate enema on the morning of surgery
What does R on (RAPRIOP) reffers to?
R - referral
- consider if ITU or HDU bed will be needed
What does last P on RAPRIOP refer to?
- the patient should be fully informed and understand the plan for their care and discharge
- major surgical patients -> need a follow up appointment in the clinic,
- day-case surgery -> telephone follow-up from a nurse specialist only or may not require follow-up
If a patient has an underlying valvular heart disease what do remember to do before the operation? (3)
- stop Warfarin 3 days before op -> switch to IV Heparin
- give antibiotic prophylaxis -> to prevent endocarditis
- do ECHO -> to assess current valvular disease
How long (if possible) to wait before the surgery after MI?
At least 6 months after MI
How long an elective surgery should be deferred for after URTI or LRTI and why?
For at least 6 weeks -> this is due to an increased risk of respiratory complications (e.g. secondary infection) if surgery under GA
What is pre-op advice for COPD patient? (3)
- stop smoking at least 8 weeks before the surgery
- optimise the condition with physiotherapy and exercise
- be admitted a day before the surgery
Pre-op considerations of DM person?
- admission 2-3 days before surgery may be needed
- should be placed first on the theatre list (to minimise risk of uncontrolled BM)
- sliding scale should be used
What’s insulin sliding scale? How to do it?
Sliding scale - progressive insulin dose pre-meal and nighttime
- IV infusion of Actrapid (fast acting insulin) is given against the patient BM
- mix with normal saline or 5% dextrose
*if patient’s BM is <15 mmol/l -> mix with dexterose
if >15 mmol/l -> mix with normal saline
Minor surgery - what to advice for diabetes:
- type 1
Minor surgery and Diabetes Type 1:
- omit morning insulin dose + commence sliding scale
- the sliding scale should be running up to the time when the patient is able to eat and drink + normal med regimen is resumed
Minor surgery and diabetes mellitus type 2 (on tablets) if:
a) scheduled for morning list
b) scheduled for afternoon liest
A) morning list -> omit morning tablets + monitor BM
B) afternoon list -> patient can have a nomal med regime and early breakfast
Pt should be encouraged to eat and drink normally ASAP after the surgery
Major surgery and type of diabetes - considerations:
a) Type 1
b) Type 2
A) type 1 -> pt should be admitted a day before the surgery and started on sliding scale
B) type 2 -> omit normal meds the night before; sliding scale on the day of the surgery
What peri- operative risks are increased in obesity?
- peri-operative MI
- arrhythmias
- HF
- DVT
- PE
Pt on Warfarin (not with the valvular disease) and pre-op considerations
- admit a day before surgery (usually warfarin is stopped 3 days before)
- switch to IV heparin infusion
* heparin infusion is stopped 4 hours before the surgery
*patients taking warfarin may be contraindicated for epidural
When to stop Aspirin and Clopidogrel before the surgery?
stop 5 days before the surgery -> as they interfere with platelet function = risk of bleeding during or after the procedure
