Perioperative Flashcards
What pre-op checks must you do on every patient?
OP CHECS
- Operative fitness (cardioresp)
- Pills
- Consent
- History (MI, asthma, HTN, jaundice, anaesthetic complications, DVT, anaphylaxis)
- Ease of intubation: neck arthritis, dentures, loose teeth
- Clexane
- Site (correct and marked)
How should you manage HRT/OCP prescribing perioperatively?
Stop 4 weeks before a major surgery/leg surgery
Restart 2 weeks post op if mobile
What blood tests should you do preoperatively?
- FBC
- U+E
- G+S
- clotting
- glucose
- Plus:
- LFTs if liver disease, EtOH, jaundice
- TFTs if thyroid disease
- Se electrophoresis if west indies, med, africa
- Cross match
- 4 units for gastrectomy
- 6 units for AAA
How long should patients be NBM for before an op?
≥2h clear fluids, ≥6h solids
What kinds of bowel preps are there?
- Stimulant e.g. picolax: picosulfate and magnesium citrate
- Osmotic e.g. Klean Prep: macrogol
What are the risks of bowel preps?
- Liquid bowel contents spilled during surgery
- Electrolyte disturbance
- Dehydration
- Increased rate of post op anaestomotic leak
When should you give antibiotic prophylaxis?
GI surgery (20% post op infection if elective) and djoint replacement; give it 15-60 mins before surgery
What prophylactic antibiotics do you give for biliary surgery?
Cef 1.5g + metronidazole 500mg IV
What prophylactic antibiotics do you give for CR or appendicectomy surgery?
Cef + met TDS
What prophylactic antibiotics do you give for vascular surgery?
co amoxiclav 1.2g IV TDS
What prophylactic antibiotics do you give for MRSA positive patients before surgery?
vancomycin
How do you manage DVT risk in surgical patients?
- Low risk: early mobilisation
- Medium risk: early mobilisation + TEDS + 20mg enoxaparin
- High risk: early mobilisation + TEDS + 40mg enoxaparin + intermittent compression boots perioperatively
- Start prophylaxis at 1800 post op
- May continue medical prophylaxis at home up to 1 month
What are the ASA grades?
- Normally healthy
- Mild systemic disease
- Severe systemic disease which limits activity
- Systemic disease which is a constant threat to life
- Moribund: not expected to survive 24h even with operation
How do you manage a permanent pacemaker/ICD in surgery?
Can be reset/triggered by diathermy. Change pacemaker to fixed pace and switch off ICD + attach external defibrillator pads
Why is diabetes a surgical risk?
- Surgery increases stress hormones which antagonise insulin
- NBM
- Increased risk of infection and poor wound healing
- IHD and PVD common
How do you generally manage IDDM patients in surgery?
- Put them first on the list and inform surgeon and anaesthetist
- May use GKI infusion
- Sliding scale may not be needed for minor ops; consult diabetic specialist nurse
- ±stop long acting insulin night before
- Omit AM insulin if morning surgery
- Start sliding scale
- 5% dex with 20mmol KCl 125ml/hr
- Infusion pump with 50u actrapid
- Check CPG hourly and adjust insulin
- Check glucose hourly aiming for 7-11mM
- Post op
- continue sliding scale until eating
- Switch to SC regimen around a meal
How do you manage NIDDM patients in surgery?
- If glucose control poor (fasting >10mM) treat as IDDM
- Omit oral hypoglycaemics on morning of surgery
- Eating post op: resume oral hypoglycaemics with meal
- Not eating post op:
- Check fasting glucose on morning of surgery
- Start insulin sliding scale
- Consult specialist team re: restarting PO treatment
How do you manage diet controlled diabetics in surgery?
Usually not a problem; they might be briefly insulin dependent post op so monitor CPG
Why do steroids increase postop risk?
Reduced neutrophil and fibroblast function
What are the risks of steroid usage perioperatively?
- Poor wound healing including anastomotic leak
- Infection
- Adrenal crisis (Addison’s)
How do you manage steroid prescribing perioperatively?
- If you can wean the dose pre op, do
- Need to increase steroid to cope with stress
- Consider cover if high dose steroids within last year
- Major surgery: hydrocortisone 50-100mg IV with pre med then 6-8 hourly for 3 days (until back on oral steroids)
- Minor: as for major but hydrocortisone only for 24h
What are the risks of operating on jaundiced patients?
- Obstructive jaundice: increased risk of post op renal failure
- Coagulopathy
- Increased infection risk may cause cholangitis
How do you manage jaundiced patients preoperatively?
- Avoid morphine in pre med
- Check clotting and consider pre op vit K
- Give 1L NS pre op (unless CCF) -> moderate diuresis
- Urinary catheter to monitor output
- Prophylaxis: cef and met
How do you manage jaundiced patients intraoperatively?
Hourly urine output monitoring and NS titrated to output
How do you manage jaundiced patients postoperatively?
Intensive monitoring of fluid status and consider CVP + frusemide if poor output despite NS
How do you classify surgical risk in liver disease?
Child’s Classification of Surgical Risk in Hepatic Dysfunction (graded A-C)
How do you generally manage anticoagulated patients perioperatively?
- Very minor surgery can be done without stopping warfarin if INR <3.5
- Avoid epidural, spinal, regional blocks if anticoagulated
- In general continue aspirin/clopidogrel unless high risk of bleeding then stop 7d before surgery
How do you manage low risk anticoagulated patients e.g. AF?
Stop warfarin 5d pre op; need INR <1.5 and restart next day
How do you manage high risk anticoagulated patients perioperatively e.g. valves, recurrent VTE?
- Need bridging with LMWH
- Stop warfarin 5d pre op and start LMWH
- Stop LMWH 12-18h pre op and restart 6h post op
- Restart warfarin next day
- Stop LMWH when INR >2
How do you manage anticoagulated patients needing emergency surgery?
- Discontinue warfarin
- Vit K 0.5mg slow IV
- Request FFP or PCC to cover surgery
What are the perioperative risks with COPD/smoking?
- Basal atelectasis
- Aspiration
- Chest infection
What are the 3 main aims of anaesthesia?
Hypnosis, analgesia, muscle relaxant
What would be the drugs used in a typical anaesthetic regimen?
- Induction: IV propofol
- Muscle relaxation: either -
- Depolarising: suxamethonium
- Non-depolarising: vecuronium, atracurium
- Airway: ET tube, LMA
- Maintenance: usually a volatile agent added to N2O/O2 mix e.g. halothane, enflurane
- End of anaesthesia: change inspired gas to 100% O2, reverse paralysis with neostigmine and atropine (prevent muscarinic side effects)
What drugs are included in operative pre medication?
- 7 As
- Anxiolytics and amnesia e.g. temazepam
- Analgesics e.g. opioids, paracetamol, NSAIDs
- Anti emetics e.g. odansetron 4mg/metoclopramide 10mg
- Antacids e.g. lansoprazole
- Anti-sialogue e.g. glycopyrolate (decreases secretions)
- Antibiotics
What agent might you use for regional anaesthesia and why would you use regional over general?
Bupivicaine (long acting). Use for minor procedures, unsuitable for GA
What are some contraindications to nerve or spinal blocks?
Local infection or clotting abnormality
What are some potential complications of anaesthesia?
- Propofol induction - cardiorespiratory depression
- Intubation
- Oropharyngeal injury with laryngoscope
- Oesophageal intubation
- Loss of pain sensation
- Urinary retention
- Pressure necrosis
- Nerve palsies
- Loss of muscle power
- Corneal abrasion
- No cough -> atelectasis and pneumonia
- Malignant hyperpyrexia from halothane or suxamethonium
- Anaphylaxis
What is malignant hyperpyrexia, what causes it and how do you treat it?
- Rare complication precipitated by halothane or suxamethonium
- AD inheritance
- Rapid rise in temperature and masseter spasm
- Treat with dantrolene and cooling
What are some common anaesthetic triggers for anaphylaxis?
Antibiotics, colloid, NM blockers like vecuronium
Why are analgesics necessary in surgery?
- Humanitarian
- Autonomic activation causes arteriolar constriction, decreased wound perfusion and therefore poor healing
- Patients might not mobilise leading to VTE and decreased function
- Decreased respiratory excursion and cough can cause atelectasis and pneumonia
What drugs are commonly given as a PCA?
Morphine, fentanyl
What drug is commonly given through an epidural?
Bupivicaine
Describe the analgesic ladder for post op pain relief
- Non opioid ± adjuvants
- Paracetamol
- NSAIDS:
- Ibuprofen 400mg/6h PO max
- Diclofenac 50mg PO/75mgIM
- Weak opioid + non opioid ± adjuvants; add:
- Codeine
- Tramadol
- Dihydrocodeine
- Strong opioid + non opioid ± adjuvants; add:
- Morphine: 5-10mg/2h max
- Oxycodone
- Fentanyl
What are the 2 main cautions when using spinal/epidural anaesthesia?
Respiratory depression and neurogenic shock causing hypotension
What are the aims of ERAS?
- Opimise pre op preparation
- Avoid iatrogenic problems like ileus
- Minimis adverse physiological/immunological responses to surgery
- Raised cortisol and low insulin (absolute or relative_
- Hypercoagulability
- Immunosuppression
- Increase speed of recovery and expedite return to function
- Recognise abnormal recovery and allow early intervention
What are the pre-op components of ERAS?
- Aggressive physical optimisation (hydration, BP, anaemia, DM, comorbidities)
- Smoking cessation ≥4 weeks before op
- Admission on day of surgery
- Avoid prolonged fast
- Carb loading prior to surgery e.g. carb drinks to reduce early catabolic response
- Fully informed patient encouraged to participate in recovery
- Avoid opiates and epidurals (GIT effects, early mobilisation)
What are the intra op components of ERAS?
- Short acting anaesthetic agents
- Epidurals
- Minimally invasive techniques
- Avoid drains and NGTs where possible
What are the post op components of ERAS?
- Aggressive treatment of pain and nausea
- Early mobilisation and physio
- Early resumption of oral intake including carb drinks from 6h
- Early discontinuation of IV fluids
- Remove drains and urinary catheters ASAP
Who is ERAS unsuitable for?
- Some IDDM
- Pre existing significantnutritional compromise
- Cognitive impairment
Define sterilisation
Removal of all viable microorganisms, vegetative and spores
Define disinfection
Removal of actively dividing vegetative microorganisms
Define antisepsis
Process whereby the risk of medical cross infection by microorganisms is reduced
What are some general surgical complications?
- Immediate (<24h)
- Intubation -> oropharyngeal trauma
- Surgical trauma to local structures
- Primary or reactive haemorrhage
- Early (1d-1month)
- Secondary haemorrhage
- VTE
- Urinary retention
- Atelectasis and pneumonia
- Wound infection and dehiscence
- Antibiotic association colitis (AAC)
- Late (>1 month)
- Scarring
- Neuropathy
- Failure or recurrence
How do you classify haemorrhage?
- Primary: continuous bleeding starting during surgery
- Reactive: bleeding at the end of surgery or early post op, secondary to increased cardiac output and BP
- Secondary: bleeding >24h post op, usually due to infection
What are the causes of post op urinary retention?
- Drugs: opioids, epidural/spinal, anti-AChM
- Pain: sympathetic activation causes sphincter contraction
- Psychogenic: hospital environment
What are the risk factors for post op urinary retention?
- Male
- Old age
- Neuropathy e.g. DM, EtOH
- BPH
- Surgery: hernia, anorectal
How do you manage post op urinary retention?
- Conservative
- Privacy
- Ambulation
- Void to running taps or in hot bath
- Analgesia
- Catheterise ± gent 2.5 mg/kg IV stat
- TWOC: trial without catheter
- If failed, may be sent home with a silicone catheter and urology follow up
What is pulmonary atelectasis and why does it happen?
Mucus plugging and absorption of distal air causes a lung collapse - happens after almost every GA
What are the causes of atelectasis?
- Pre op smoking
- Anaesthetics
- Increased mucus production
- Decreased mucociliary clearance
- Pain inhibits respiratory excursion and cough
How does atelectasis present?
- Within first 48 hours
- Mild pyrexia
- Dyspnoea
- Dull bases with reduced air entry
How is atelectasis managed?
Good analgesia to aid coughing and chest physio
When does wound infection present and what are the usual organisms?
5-7d post op with S aureus and coliforms
What is the difference between clean, contaminated and dirty?
- Clean: incise uninfected skin without opening viscus
- Clean/contaminated: intra op breach of viscus (not colon)
- Contaminated: breach of viscus + spillage or opening of colon
- Dirty: site already contaminated - faeces, pus, trauma
What are the risk factors for wound infection?
- Preoperative
- Old age
- Comorbidities e.g. DM
- Pre existing infection e.g. appendix perforation
- Patient colonisation e.g. nasal MRSA
- Operative
- Op classification and wound infection risk
- Duration
- Technical: pre op antibiotics, asepsis
- Post operative
- Contamination of wound from staff
How is wound infection managed?
Regular dressing, antibiotics, abscess drainage
How does wound dehiscence present?
About 10 days post op, preceded by serosanguinous discharge from wound
What are the risk factors for wound dehiscence?
- Pre op
- Old age
- Smoking
- Obesity, malnutrition, cachexia
- Comorbs: BM, uraemia, chronic cough, cancer
- Drugs: steroids, chemo, radio
- Operative factors:
- length and orientation of incision
- Closure: follow Jenkin’s Rule
- Suture material
- Post op factors
- Increased IAP e.g. prolonged ileus -> distension
- Infection
- Haematoma/seroma formation
What is Jenkin’s rule?
Suture length = 4x length of wound,
How is wound dehiscence managed?
- Replace abdo contents and cover with sterile soaked gauze
- IV antibiotics: cef and met
- Opioid analgesia
- Call senior and arrange theatre
- Repair in theatre:
- Wash bowel
- Debride wound edges
- Close with deep non absorbable sutures (e.g. nylon)
- May need vac dressing or grafting
What are the complications of cholecystectomy?
- Conversion to open (5%)
- CBD injury (0.3%)
- Bile leak
- Retained stones (needing ERCP)
- Fat intolerance/loose stools
What are the complications of inguinal hernia repair?
- Early
- Haematoma/seroma formation (10%)
- Intra abdominal injury (lap)
- Infection (1%)
- Urinary retention
- Late
- Recurrence (<2%)
- Ischaemic orchitis (0.5%)
- Chronic groin pain/paraesthesia (5%)
What are the complications of appendicectomy?
- Abscess formation
- Fallopian tube trauma
- Right hemicolectomy (e.g. for carcinoid, caecal necrosis)
What are the complications of colonic surgery?
- Early
- Ileus
- AAC
- Anastomotic leak
- Enterocutaneous fistulae
- Abdominal or pelvic abscess
- Late
- Adhesions -> obstruction
- Incisional hernia
What are the causes of post op ileus?
- Bowel handling
- Anaesthesia
- Electrolyte imbalance
How does post op ileus present?
- Distension
- Conspitation ± vomiting
- Absent bowel sounds
How is post op ileus treated?
IV fluids, NGT, TPN if prolonged
What are the complications of anorectal surgery?
- Anal incontinenece
- Stenosis
- Anal fissure
What are the complications of small bowel surgery?
Short gut syndrome (if ≤250cm)
What are the complications of splenectomy?
- Gastric dilatation (secondary gastric ileus) - prevent with NGT
- Thrombocytosis -> VTE
- Infection: encapsulated organisms
What are the complications of arterial surgery?
- Thrombosis and embolisation
- Anastomotic leak
- Graft infection
What are the complications of aortic surgery?
- Gut ischaemia
- Renal failure
- Aorto-enteric fistula
- Anterior spinal syndrome (paraplegia)
- Emboli -> distal ischaemia (trash foot)
What are the complications of breast surgery?
- Arm lymphoedema
- Skin necrosis
- Seroma
What are the complications of urological?
- Sepsis (instrumentation with infected urine)
- Uroma: extravasation of urine
What are the complications of prostatectomy?
- Urinary incontinence
- Erectile dysfunction
- Retrograde ejaculation
- Prostatitis
What are the complications of thyroidectomy?
- Wound haematoma -> tracheal obstruction
- Recurrent laryngeal nerve trauma -> hoarse voice
- Transient in 1.5%
- Permanent in 0.5%
- R commonest (more medial)
- Hypoparathyroidism -> hypocalcaemia
- Thyroid storm
- Hypothyroidism
What are the complications of tracheostomy?
- Stenosis
- Mediastinitis
- Surgical emphysema
What are the complications of fracture repair?
- Mal/non union
- Osteomyelitis
- AVN
- Compartment syndrome
What are the complications of hip replacement?
- Deep infection
- VTE
- Dislocation
- Nerve injury: sciatic, SGN
- Leg length discrepancy
What are the complications of cardiothoracic surgery?
- Pneumo/haemothorax
- Infection: mediastinitis, empyema
What are the causes of post-op pyrexia?
- Early: 0-5 days post op
- Blood transfusion
- Physiological: SIRS from trauma: 0-1d
- Pulmonary atelectassi: 24-48 hours
- Infection: UTI, superficial thrombophlebitis, cellulitis
- Drug reaction
- Delayed: >5d post op
- Pneumonia
- VTE (5-10d)
- Wound infection (5-7d)
- Anastomotic leak (7d)
- Collection (5-20d)
What investigations should you do in a patient with post op pyrexia?
- Urine: dip and MC+S
- Bloods: FBC, CRP, cultures ± LFTs
- Cultures: wound swabs, CVP tip
- CXR
What are the causes of post op pneumonia?
- Anaesthesia causing atelectasis
- Pain decreasing cough
- Surgery causing immunosuppression
How do you treat post op pneumonia?
Chest physio (encourage cough), good analgesia, antibiotics
How does a collection present?
- Malaise
- Swinging fever, rigors
- Localised peritonitis
- Shoulder tip pain (if subphrenic)
Where are some common locations for collections?
- Pelvic (present 4-10 days post op)
- Subphrenic (7-21d post op)
- Paracolic gutters
- Lesser sac
- Hepatorenal recess (Morrison’s space)
- Small bowel (interloop spaces)
What investigations should you do if you suspect a collection?
FBC, CRP, cultures
US, CT
Diagnostic lap
How do you treat a collection?
Antibiotics, drainage/washout
What is cellulitis?
Acute infection of the subcutaneous connective tissue
What are the common causative organisms of cellulitis?
Beta haemolytic streps and staph aureus
How does cellulitis present?
- Pain, swelling, erythema, warmth
- Systemic upset
- ± lymphadenopathy
How do you treat cellulitis?
- Benpen IV
- Pen V and fluclox PO
How common is DVT in surgical patients?
25-50%
What are the risk factors for DVT?
Virchow’s triad:
- Blood contents
- Surgery increases platelets and fibrinogen
- Dehydration
- Malignancy
- Old age
- Blood flow
- Surgery
- Immobility
- Obesity
- Vessel wall
- Damage to veins (especially pelvic)
- Previous VTE
How does DVT present?
- 5-10d post op
- 65% below knee are asymptomatic
- Calf warmth, tenderness, erythema, swelling
- Mild pyrexia
- Pitting oedema
What are the differentials for DVT?
Ruptured Baker’s cyst, cellulitis
What investigations should you do in DVT?
- D dimer: sensitive but not specific
- Compression US (clot incompressible)
- Thrombophilia screen if
- No precipitating factors
- Recurrent DVT
- Family history
How do you diagnose DVT?
- Assess probability with Wells’ score
- Low probability - do a D dimer
- Negative excludes DVT
- Positive do a compression Us
- Medium/high probability do a compression US
How do you treat DVT?
- Therapeutic LMWH: enoxaparin 1.5mg/kg/24h SC
- Start warfarin using Tait model: 5mg OD for first 4d
- Stop LMWH when INR 2.5
- Duration
- Below knee: 6-12 weeks
- Above knee: 3-6 months
- Ongoing cause: indefinite
- And consider graduated compression stockings to prevent post-phlebitic syndrome
How can you prevent DVT?
- Pre op
- VTE risk assessment
- TED stockings
- Aggressive optimisation especially hydration
- Stop OCP 4 weeks prior
- Intra op
- Minimise length of surgery
- Use minimal access surgery where possible
- Intermittent pneumatic compression boots
- Post op
- LMWH
- Early mobilisation
- Good analgesia
- Physio
- Adequate hydration
What are some causes of post op dyspnoea?
- Previous lung disease
- Atelectasis, aspiration, pneumonia
- LVF
- PE
- Pneumonthorax e.g. due to CVP line insertion
- Pain -> hypoventilation
What are the causes of reduced urine output post op?
- Post renal
- Commonest cause
- Blocked/malsited catheter
- Acute urinary retention
- Pre renal: hypovolaemia
- Renal: NSAIDs, gentamicin
- Anuria is usually blocked or malsited catheter
- Oliguria is usually inadequate fluid replacement
How do you manage reduced urine output post op?
- Information:
- Operative history
- Obs chart: urine output
- Drug chart: nephrotoxins
- Examination
- Assess fluid status
- Examine for palpable bladder
- Inspect drips, drains, stomas, CVP
- Action
- Flush with 50ml NS and aspirate back
- Fluid challenge
What are the causes of post op nausea and vomiting?
- Obstruction
- Ileus
- Emetic drugs like opioids
How is post op nausea and vomiting managed?
Consider NGT and AXR
Give odansetron 4mg IV TDS
What are the common causes of post op hyponatraemia?
- SIADH: pain, nausea, opioids, stress
- Overadministration of IV fluids
How do you treat post op hyponatraemia?
Look at pre op level and correct slowly:
- Acute: 1mM/h
- Chronic: 15mM/d
How do you manage post op hypotension?
- IMMEDIATE: tild bed head down, give O2, assess fluid status
- Hypovolaemia: fluid challenge of 250-500ml colloid over 15-30 mins
- Haemorrhage: back to theatre
- Sepsis: fluid challenge and start antibiotics
- Overload: frusemide
- Neurogenic: NA infusion
What are some causes of post op hypotension?
- Cardiogenic
- MI
- Fluid overload
- Hypovolaemia
- Inadequate replacement
- Haemorrhage
- Obstructive
- PE
- Distributive
- Sepsis
- Neurogenic shock
What are some causes of post op hypertension?
Pain, urinary retention, previous HTN
How do you treat post op hypertension?
Treat the cause but can use labetalol 50mg IV every 5 mins (200mg max)
What are the common causes of acute confusional state?
- Drugs: opiates, sedatives, L-DOPA
- Eyes, ears and other sensory deficits
- Low O2 states: MI, stroke, PE
- Infection
- Retention: stool or urine
- Ictal
- Under-hydration/nutrition
- Metabolic: Na, AKI, glucose, EtOH withdrawal
How do you treat acute confusional state?
- May need sedation: midazolam/haldol
- Nurse in a well-lit environment
- Treat cause
