2 - Perioperative Care Flashcards
What is the aim of perioperative planning?
To optimise patients before elective surgical procedures.
What things are important to note from the Hx prior to surgery?
Key info - cardiac and respiratory fitness.
Dysrrhythmia, HF and IHD are significant concerns
Which score can be used to predict difficult intubation?
LEMON score
Which scoring system assesses availability of access to the throat via the mouth?
Mallampati score
1-4
When are U&Es requested prior to surgery?
Major ops
Elderly Ps
Significant blood loss anticipated or meds that affect electrolytes
Endocrine or comorbidities
Which groups of medications affect electrolyte levels?
Steriods
NSAIDs
Diuretics
When are ECGs done prior to surgery?
Over 65
Sig comorbidities
CVS Hx
When do clotting screens need to be done prior to surgery?
Hx of bleeding disorder
Liver disease
Eclampsia
FHx bleeding disorders
Anthrombotic or anticoagulant meds
When is a urinalysis dipstick done prior to surgery?
Done in all Ps to detect infection, biliuria, glycosuria and inappropriate osmolality
When would you do LFTs prior to surgery?
Ps with
- Jaundice
- Cirrhosis
- Chronic liver pathology
- Malignancy
- Poor nutritional status
- Excess alcohol
What testing can be done in preoperative care to assess cardiorespiratory function before surgery?
Cardiopulmonary exercise testing (CPET)
What is the anaerobic threshold in CPET?
The point at which anaerobic respiration begins in the tissues.
At what anaerobic threshold would there be a significant inc risk of mortality with major surgery?
<11ml/min/kg
What is a poor predictor of exercise tolerance?
Low ejection fraction
Less than 30% = poor patient outcome
What is a good indicator of acceptable cardiovascular status for surgery?
If Ps can climb a flight of stairs without getting SOB or chest pain
When should you get cardiology input on pre-operative status?
If Ps have
Murmur + symptomatic
Poor LV function of HCM/DCM
Ischaemic changes on ECG
New abnormal rhythm on ECG
What should BP be below ideally before surgery?
180/110
How does aortic stenosis affect surgical risk?
Aortic stenosis - fixes cardiac output.
During surgery - is increased demands for O2. This would normally be met by increased CO. AS prevents this from happening = increases surgical risk.
What type of medication should be given to Ps with metallic heart valves prior to surgery?
Anticoagulants
If a patient has had a proven MI - how long should elective surgery be postponed for? Why?
Should be postponed for 3-6 months
Reduces the risk of perioperative MI.
If a P has recently had an MI and surgery cannot be postponed - what should be given?
DAPT can be given during surgery but is often reduced to a single agent as it has a sig risk of bleeding
Which medication should be worried about starting pre-operatively?
Β-blockers - possibly inc risk of stroke in these Ps.
Which medications
- should be stopped 5 days prior to surgery
- should be stopped 2-3 days prior to surgery
- should be maintained over perioperative period
- should be stopped 24 hours prior to surgery
0
Warfarin - stopped 5 days prior
DOACs - stop 2-3 days prior
Maintain - β blockers, statins and corticosteriods (can covert to IV steroids if oral absorption not available for a while)
Stop ACEIs and ARBs 24 hours prior to surgery
For Ps on long term antiocoagulation - a risk/benefit assessment should be done to decide whether it is safe to stop their medications prior to surgery.
What can be given to high risk VTE patients (?
Bridging therapy - unfractionated or LMWH
Which patients are a high VTE risk?
Those with a metallic heart valve
Or those with recent drug eluting cardiac stent
Which scoring system can be used to calculate stroke risk for Ps with AF?
CHA2DS2-VASC
Which is the commonest family Hx coagulopathy in UK?
Factor V Leiden mutation
How soon prior to surgery should
- unfractionated heparin
- LMWH
be stopped?
UFH = 6hrs prior
LMWH = 12 hours prior
What should Ps with coagulation disorders be given in the perioperative period?
Thromboprophylaxis
What is the rate of DVT during general surgery without prophylaxis?
15-30%
What are the RF for DVT during surgery?
> 60
Obesity
Hx of VTE
Cancer
Prolonged bed rest
Major surgery
CHF
# hip or lower limb
Oestrogen meds
Multiple trauma
If you have multiple RF - risk increases significantly
Which are the strongest RF for DVT?
Cancer (esp if on chemo - massive inc)
Orthopaedic surgery
Truama
What does TED stand for in stocking?
Thromboembolic deterrent
What are the CI for using TED stockings?
Arterial insufficiency
Heel pressure ulcers
Leg swelling too tight for stockings
What advantages does LMWH have over heparin?
Once daily injection (rather than infusion)
Higher activity
No monitoring required
Fewer bleeding complications
Which Ps should have extended prophylaxis with LMWH?
Cancer
Major surgery
Neurological surgery
Emergency surgery
What should happen do ICDs during surgery?
Should be switched off so they dont shock the P during surgery
What type of diathermy can be used with an ICD or PPM?
Dont use monopoly diathermy
Use bipolar or non-electrocautery
Which heart blocks need cardiology input and possible temporary/permament pacemaker insertion prior to surgery?
Asymptomatic Mobitz II and 3rd degree
What should you do for Ps with DM who need surgery?
Get pre-op HbA1c
Keep sugars controlled when not eating - can give IV insulin
Try and put diabetic Ps first on the list so they dont need to be starved for long periods
What can be don to improve respiratory function prior to surgery?
Preoperative inspiratory muscle training
When should Ps be referred to a respiratory consultant prior to surgery?
- Severe disease or deterioration
- Major surgery in P who has SIGNIFICANT respiratory comorbidities
- RHF suspected
- P is found and has severe respiratory problems
How is body mass index worked out?
Weight (kg) / Height (m2)
What score is used to calculate risk of obstructive sleep apnoea?
STOP BANG score
What should happen to Jehovah’s Witnesses pre-operatively?
Give pre-operative iron infusion if anaemic
Get specific consent form to clarify what is / what is not acceptable
May accept autotransfusion
What is pre-optimisation of Ps prior to major surgery called?
Prehabilitation
How can prehabilitation improve outcomes?
Can reduce length of stay
Reduce post op complications and mortality
May improve post op QOL
What is it important to tell frail Ps?
That they may not get back to their pre-operative function - and it may end up with them losing their independence.
How much of your fluid is intracellular and extracellular?
2/3 intracellular
1/3 extracellular
What forces fluid out of the intravascular compartment and into the interstitial compartment?
A combination of hydrostatic and oncotic pressures.
What are the normal serum levels of
- Na
- K
- Cl
- HCO3
- Osmolality
Na = 135-145
K - 3.5-5.5
Cl = 98-108
HCO3 = 22-30
Osmolality = 275-295
What is the minimum amount of
- Na
- K
- Fluid
you need each day?
Na = 1-2 mmol per kg
K = 1 mmol per kg
Fluid = 40ml per kg
Which fluids are high in Na?
0.9% saline
Hartmann’s
Which fluid has the closest osmolality to normal blood?
Hartmann’s
How do you determine which fluids to prescribe?
- Is there a fluid deficit or is it maintenance fluids only?
- Can the P drink rather than using fluids?
- What is the nature of the fluid deficit - which type of fluid would be best to treat?
- Does salt need replacing - 0.9%? or other parameters - Hartman’s? or do we just want to replace water vol - therefore 5%
How much fluid is allowed pre-operatively?
Up to 50ml per hour of clear fluid to avoid pre-op dehydration
Why does peri-operative fluid management differ between elective and emergency surgery?
Elective - Ps are optimised, fluid-neutral and the electrolytes are hopefully in a good place - not necessarily the same in emergency surgery.
What is AKI defined as?
Rapid reduction in kidney function
+
Rise in creatinine >25 or 1.5 fold inc from baseline
What is the more accurate measure of AKI in elderly Ps?
Creatinine
What is the cause of AKI presumed to be in surgical Ps?
Hypovolaemia - most Ps have fluid losses during surgery
What do you need to monitor in terms of AKI with Ps who have renal or cardiac impairment?
K level - much lower therapeutic window
Avoid NSAIDs in these Ps too
When should Ps restart oral fluids postoperatively?
ASAP
What is the most sensitive measure of fluid balance / end organ perfusion?
Urine output
What is oliguria defined as?
<0.5ml/kg/hr
What is the absence of urine output called?
Anuria
What is anuria most often caused by?
Outflow obstruction
What should you give with NSAIDs?
PPI cover
And monitor renal function
What would a good analgesia plan be postoperatively for many Ps?
Regular paracetamol
Regular NSAID if appropriate
Regular mild opioid
PRN strong opioid for breakthrough pain
If significant pain - consider regular strong opioid
If pain remains uncontrolled - may need input from pain team / anaesthetics
What AE can be caused by local anaesthesia?
At high doses - can cause cardiac toxicity
When is patient controlled analgesia contra-indicated?
If Ps aren’t capable of understanding / using
Can’t be used if Ps are asleep
What is the ebb phase in response to injury?
Shock
= hypovolaemia
= decreased basal metabolic rate
= reduced CO
= hypothermia
= lactic acidosis
Can last 24-48 hours
What follows the ebb phase in response to injury?
Flow phase - hyper-catabolic state
What happens in the flow phase?
When does this occur?
Hyper-catabolic state - body stating to promote healing - improving delivery of metabolites to the tissues
- Fluid and electrolyte retention
- Promotes healing and fights infection
Occurs days 3-7
What happens after the flow phase?
Recovery phase = anabolic state - repair of tissues and restoration of homeostasis
What does prolonged stress response mean for recovery?
Greater tissue damage and delayed recovery
Post-op = try to offset some of these stressors as the longer they occur the greater the damage and longer the recovery
How do we try to reduce stress response post operatively?
ERAS = Enhanced recovery after surgery
- Pain control - reduces cortisol etc
- Minimally invasive surgery - reduces burden P has to come back from
- Optimal nutrition and fluids - reduces impact of hyper-catabolic phase
- avoid tissue oedema by not giving excessive intra-operative fluids
Which compounding factors that prolong recovery do we try to avoid postoperatively?
- Continuing haemorrhage
- Hypothermia (inc risk of arrhythmias)
- Oedema - can reduce gas exchange and perfusion
- Tissue under perfusion (avoid lactic acidosis)
- Starvation
- Immobilisation - want to get Ps up and moving as quickly as possible
