Pre-operative care Flashcards
ASA grading: what is it?
The American Society of Anesthesiologists (ASA) grading system classifies the physical status of the patient for anaesthesia. Patients are given a grade to describe their current fitness prior to undergoing anaesthesia/surgery
ASA I – normal healthy patient
ASA II – mild systemic disease
ASA III – severe systemic disease
ASA IV – severe systemic disease that constantly threatens life
ASA V – “moribund” and expected to die without the operation
ASA VI – declared brain-dead and undergoing an organ donation operation
E – this is used for emergency operations
ASA grade 1
ASA I – normal healthy patient
Define the acronym RAPRIOP
Reassure
Advice
Prescription
Referral
Investigations
Observations
Patient understanding
Don’t forget follow-up
Reassurance
Check patient understanding of procedure
ICE
Address concerns
Advice (when to fast)
Clear fluids - 2 hours before surgery
Foods and dairy - 6 hours before surgery
Why do you advise patients to fast?
Fasting ensures that the stomach is empty of contents. This reduces the risk of reflux during intubation and extubation, which could lead to pulmonary aspiration.
(Complications covered in another card)
Potential complications related to con-compliance with fasting?
- Aspiration pneumonitis (inflammation caused by very acidic gastric contents, leading to desquamation)
- Aspiration pneumonia (due to secondary infection following pneumonitis or direct aspiration of infected material).
Prescriptions to stop
CHOW
Clopidogrel - 7 days prior to surgery due to bleeding risk (aspirin and other anti-platelets can be continued)
Hypoglycaemics (covered in more detail in another card)
Oral contraceptives and HRT - 4 weeks prior to surgery (DVT risk) –> use barrier contraception during this time
Warfarin - 5 days prior to surgery (bleeding risk). Started on LMWH instead
- If on warfarin and INR>1.5 the night before surgery –> PO vitamin K (1–5 mg, IV preparation to be used PO, dose to be given the day before surgery if INR ≥1.5.
If emergency surgery –> 5mg PO +/- dried prothrombin complex
Prescriptions to alter
- Subcutaneous insulin (discussed in another card)
- Long-term steroids (>5mg oral prednisolone)
If the patient cannot take these orally, switch to IV (a simple conversion rate is 5mg PO prednisolone = 20mg IV hydrocortisone)
Pre-operative long-term steroids management
1. What to prescribe?
2. Why is it prescribed?
- Additional IV hydrocortisone at induction and for the immediate postoperative period (e.g., first 24 hours)
Doubling of their normal dose once they are eating and drinking for 24 – 72 hours depending on the operation
- Surgery elicits a stress response which activates the HPA axis –> increase in the release of endogenous corticosteroids. In patients on long-term steroids, there is adrenal suppression that prevents them from creating the extra steroids required to deal with this stress.
Patients on steroid therapy (more than physiological replacement) for over two weeks may experience HPA axis suppression. Patients with confirmed (or suspected) HPA axis suppression (through Short Synacthen testing) are therefore at risk of acute adrenal insufficiency (Addisonian crisis) peri-operatively due to their attenuated ability to mount a sufficient endogenous steroid response.
Prescriptions to start
- LMWH e.g. enoxaparin (clexane) –> VTE assessment must be carried out.
Except –> neck or endocrine surgery - TED stockings
Check contraindications e.g. severe peripheral vascular disease, peripheral neuropathy, recent skin graft, severe eczema. - Antibiotic prophylaxis
Peri-operative management of Diabetes Mellitus: T1DM
1. Night before surgery
2. While NBM
3. When swapping back from sliding scale to basal insulin
- Night before surgery:
1. reduce their subcutaneous basal insulin dose by 1/3rd. \
2. Omit their morning insulin and commence sliding scale (49.5mL of normal saline with 50 units of Actrapid) - While NBM:
1. Prescribe 5% dextrose at a rate of 125mL/hr
2. 2-hourly CBG check (ask nurse) - When swapping back from sliding scale to basal insulin: give SC insulin 20min before a meal and stop IV infusion 30-60min afterwards
Peri-operative management of Diabetes Mellitus: T2DM
If diet-controlled, then no perioperative management required
If controlled by oral hypoglycaemics: STOP
1. Stop metformin in the morning of surgery; other hypoglycaemics app 24hrs before surgery
2. These patients will then be put on IV variable rate insulin infusion along with 5% dextrose as Type I diabetic
What is understood by bowel preparation?
Enemas or laxatives
Why are bowel preparations used less frequently?
Can lead to fluid shifts in cardiac/renal/elderly patients, leading to lengthened stay
What surgeries require bowel preparation?
- Left hemi-colectomy, sigmoid colectomy, or abdominal-perineal resection: Phosphate enema on the morning of surgery
- Anterior resection: 2 sachets of picolax the day before or phosphate enema on the morning of surgery
Blood products in surgery: what needs to be done pre-operatively?
Group Save + Crossmatch (X-match)
Referral?
Potential HDU/ITU bed
Patient understanding and follow up
Ensure that the patient is fully informed and understands the plan for their care and discharge.
Book follow-up clinic
Patients undergoing day-case surgery will receive telephone follow-up from a nurse specialist only or may not require follow-up.
The preoperative assessment: aims and timing
Aim: identify co-morbidities that may lead to patient complications during the anaesthetic, surgical, or post-operative period
Timing: 2-4 weeks before surgery
The preoperative assessment: Pre-operative history - points to focus on
Follow standard framework for hx, but focus on these points too
PMH
- Cardio: exercise tolerance, exertional chest pain, syncopal episodes, or orthopnoea
- Respiratory: able to lie flat for a prolonged period or has a chronic cough? –> may preclude spinal anaesthesia; OSA risk factors?
- Endocrine: Diabetes/thyroid?
- GORD: can lead to aspiration pneumonia; is it controlled?
- Pregnancy: urinary pregnancy test in reproductive age females
- Sickle cell disease:
Past anaesthetic hx
- Administered anaesthesia before? If so, for what operation and what type of anaesthesia? Were there any problems? Did the patient experience any post-operative nausea and vomiting?
DH - see other cards for what to stop/alter/start
FH: rare, but malignant hyperthermia
The preoperative assessment: examination
General (cardio, abdo, resp, neuro) + anaesthetic examination (airway)
The preoperative assessment: Investigations - Blood tests
- FBC: anaemia or thrombocytopenia can be corrected pre-operatively to reduce the risk of cardiovascular events or allow for preparation of blood products
- U&Es: baseline renal function, which help inform fluid management and drug decisions, both for anaesthesia and post-operative analgesia (e.g. morphine is generally avoided in those with CKD)
- LFTs: liver metabolism and synthesising function, useful for peri-operative management; If impairment –> LFTs may help direct medication choice and dosing
- Condition-specific blood tests e.g. HbA1C or thyroid function tests (TFTs)
- Clotting Screen
- Group and Save (G&S) +/- cross-matching
What is the difference between group & save and crossmatch?
- G&S: determines the patient’s blood group (ABO and RhD) and screens the blood for any atypical antibodies; takes 40 minutes and no blood is issued
- recommended if blood loss is not anticipated, - Cross-match: mixing the patient’s blood with the donor’s blood. If no immune reaction takes place: the donor blood is issued and can be transfused in to the patient, otherwise alternative blood is trialled
- Takes ~40 minutes (in addition to the 40 minutes required to G&S the blood, which must be done first),
- Should be done pre-emptively if blood loss is anticipated
