Surgery 1 Flashcards

(33 cards)

1
Q

Pre-operative Assessment

A

Assess cardiorespiratory system, exercise tolerance, existing illnesses, drugs and allergies.

Identify risk factors – unstable neck (e.g. is arthritis – may complicate intubation), history of MI, diabetes, asthma, hypertension, rheumatic fever, epilepsy or jaundice.

Any specific risks – is the patient pregnant and have there been any previous anaesthetic complications e.g. nausea or DVT?

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2
Q

Pre-operative Investigations - Bloods

A
  • General bloods – all patients should have FBC, Us and Es and blood glucose.
  • Crossmatching – e.g. group and save for mastectomy or cholecystectomy, crossmatch 2 units for Caesarean section, 4 units for a gastrectomy or 6 units for aortic aneurysm surgery.
  • Specific bloods – e.g. LFTs in jaundice, malignancy or alcohol abuse, amylase in acute abdominal pain, drug levels if patient is on digoxin or lithium, clotting studies in liver or renal disease, DIC, massive blood loss or if on valproate, warfarin or heparin. In addition HIV and HBsAg antigens in high risk patients and sickle test in those from Africa, West Indies or Med.
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3
Q

Pre-operative Investigations - Other Tests

A
  • CXR – if known cardiorespiratory disease, pathology or symptoms, possible mets or >65 years.
  • ECG – if >55 years, poor exercise tolerance, history of MI, hypertension or rheumatic fever.
  • Echo – may be performed if there is any suspicion of poor left ventricular function.
  • Pulmonary Function tests – in patients with known respiratory disease or in obese patients.
  • Lateral cervical spine x-ray – if history of RA, ankylosing spondylitis or Down’s syndrome.
  • MRSA screen – colonisation is not a contraindication for surgery but the patient may be put last on the list to minimise the risk of transmission to others and given vancomycin.
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4
Q

ASA Classification

A
  • Class I – the patient is normally healthy.
  • Class II – the patient has a mild systemic disease.
  • Class III – the patient has a severe systemic disease that limits activity but is not incapacitating.
  • Class IV – patient has an incapacitating systemic disease which poses a constant threat to life.
  • Class V – the patient is moribund – not expected to survive 24 hours even with the operation.
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5
Q

Pre-op - Antibiotics

A

Tetracycline and neomycin may increase the neuromuscular blockade.

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6
Q

Pre-op - Anticoagulants

A

Avoid epidural, spinal and regional blocks.

Aspirin should be continued unless there is a major risk of bleeding and discuss clopidogrel with a cardiologist or neurologist.

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7
Q

Pre-op - Anticonvulsants

A

Give as usual pre-op.

Post-op give IV or via the NG tube until oral intake is possible. Give usual valproate dose IV and give a slow dose of IV phenytoin and monitor ECG.

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8
Q

Pre-op - Beta Blockers

A

Continue up to and including day of surgery to prevent a labile cardio response.

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9
Q

Pre-op - Contraceptive Steroids and HRT

A

Stop 4 weeks before major or leg surgery and ensure adequate alternative contraception is used.

Restart contraceptive steroids 2 weeks after surgery.

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10
Q

Pre-op - Digoxin

A

Continue up to and including the day of surgery – check for toxicity with ECG and levels and do plasma K+ and Ca+ (suxamethonium can increase K+ and cause arrhythmias).

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11
Q

Pre-op - Diuretics

A

Beware of hypokalaemia, dehydration (especially as nil by mouth) and do Us + Es (also check bicarbonate).

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12
Q

Pre-op - Levodopa

A

Can cause possible arrhythmias when patients are under general anaesthetic.

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13
Q

Pre-op - Lithium

A

Get expert help – it may potentiate neuromuscular blockade and cause arrhythmias.

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14
Q

Pre-op - MAOI

A

Interactions can cause hypotensive or hypertensive crisis.

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15
Q

Pre-op - Tricyclics

A

These can enhance adrenaline and cause arrhythmias

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16
Q

Pre-operative Preparation

A
  • Fast the patient – keep them nil by mouth >2 hours for clear fluids and >6 hours for solids.
  • Check - does the patients require any bowel or skin preparations or prophylactic antibiotics.
  • DVT prophylaxis – as indicated e.g. graduated compression stockings and 5000U heparin SC 2 hours pre-op and then every 8-12 hours SC for 7 days or until ambulant or 20mg enoxaparin.
  • Write up pre-meds, book pre, intra or post-operative xrays or frozen sections and book physio.
  • If required – catheterise and insert a Ryle’s (nasogastric) tube to reduces organ bulk.
17
Q

Consent and Capacity

A
  • For consent to be valid – it can be given at any time (earlier is better), the proposed investigation or treatment must be clearly understood by the patient (including risks, benefits, additional procedures, alternative courses of action and their consequences), it must be given voluntarily, sought by the doctor performing procedure and the patient must have capacity (time and decision dependant).
  • Capacity – patient must be able to understand, believe, retain and weigh the necessary information.
18
Q

Consent - Special Circumstances

A
  • Consent in children – those <16 years can give consent provided they understand what it involves – this is known as Gillick competence (although it is still good practice to involve the parents in the decision if the child is willing). For those <18 years and refusing life-saving treatment the law is less clear – talk to the parents, seniors and in some cases the duty judge.
  • Consent in the incapacitated – no-one including parents, relatives or members of the healthcare team can give consent on behalf of a patient. Proceeding in the patients best interest is decided by the clinician overseeing their care.
19
Q

Classification and Risk of Wound Infections

A
  • Clean - incising uninfected skin without opening a viscous = <2%
  • Clean - contaminated - intraoperative breach of a viscous that is not the colon = 8-10%
  • Contaminated - breach of a viscous + spillage or opening of the colon = 12-20%
  • Dirty - the site is already contaminated by pus or faeces = 25%
20
Q

Prophylactic Antibiotics

A

Given to counter the risk of wound infection which occurs in 20% of elective GI surgery and 60% of emergency surgery.

Also given when there is infection elsewhere and a systemic infection would have severe consequences e.g. when a patient has a prosthetic joint or valve.

They are given 15-60 mins prior to the procedure so the skin concentration is maximised and may be given as a single dose, 3 doses or more.

Sepsis may lead to haemorrhage and wound dehiscence

21
Q

Common Antibiotic Regimes

A
  • Biliary surgery – 1 dose of 1.5g Cefuroxime IV and Metronidazole.
  • Appendectomy – if uncomplicated a surgery a single dose of 1.5g Cefuroxime IV is effective.
  • Colorectal surgery – 1-3 doses 1.5g Cefuroxime IV TDS and 500mg Metronidazole IV TDS. If there is heavy soiling during the surgery you can also give 1-3 doses 4.5g Tazocin IV TDS.
  • Vascular surgery – 1.2g Co-amoxiclav or 1.5g Cefuroxime IV with 500mg Metronidazole.
  • MRSA – an increasing concern and may warrant prophylactic treatment – Vancomycin.
22
Q

Bowel Preparations

A

There are clear benefits of using a bowel preparation when visualisation of the lumen is required e.g. colonoscopy.

However the intended benefit for elective open procedures of minimising post-operative infection may be outweighed by the complications – liquefying bowel contents which are spilled during surgery, electrolyte loss leading to hyponatraemia and seizures, a higher rate of post-operative anastomosis leakage, increased risk of perforation and dehydration.

  • Right sided operations – give a low residue diet for a few days and clear fluids the day before the op.
  • Left sided and rectal operations – laxatives and an enema are usually used pre-operatively.
  • Example regime – 1 sachet of Picolax at 8am and another 6-8 hours later on the day before surgery.
23
Q

Surgical Drains

A
  • Most are inserted to drain the area of surgery under suction or negative pressure and are removed when stop draining. They are used to protect against collection, haematoma and seroma formation.
  • The second type of drains are used to protect sites where leakage may occur in the post-operative period e.g. at bowel anastomoses. They form a tract and are usually removed after around 1 week.
  • The third type of drains e.g. Ballovac collect red blood cells from the operation site which can be autotransfused within 6 hours protecting from the hazards of allotransfusion – used in orthopaedics.
24
Q

Types of Sutures

A

Can be broadly divided into absorbable or non-absorbable, synthetic or natural and monofilament, twisted or braided.

Monofilament sutures can be slippery but minimise infection and produce less reaction (natural fibres produce a vigorous reaction).

Braided and twisted sutures produce secure knots but may allow infection to occur between strands.

3.0 or 4.0 are smaller and used on the skin.

25
Removal of Sutures
Depends on the site and general health of the patient. Scalp, face and neck sutures can be removed after ***5 days***, abdominal and proximal limb after ***10 days*** and those on the distal extremities after ***14 days***. In patients with ***poor wound healing*** (e.g. on steroids, with malignancy, infection, cachexia, the elderly or smokers) the sutures may need ***even longer*** than 14 days.
26
Anaesthesia - Pre-medication
Aims to ***reduce anxiety*** and make ***anaesthesia easier*** to conduct. Oral medication should be given 2 hours and intramuscular medication 1 hour before surgery. ***Typical regimes*** include: * ***Anxiolytics*** – benzodiazepines e.g. 10-20mg Temazepam PO 30 minutes prior to the procedure. * ***Analgesics*** – patients can be given opioids, local anaesthetic blocks, paracetamol or NSAIDs. * ***Antiemetics*** – 5-HT3 antagonists e.g. 4mg Ondansetron IV or IM are the most effective agents. * ***Antacids*** – 50mg Ranitidine IV can be given to patients who are at high risk of aspiration. * ***Antibiotics*** – are sometimes given to decrease the risk of post-operative infection.
27
Principles of Anaesthesia
* ***Induction*** – either intravenous e.g. 1.5-2.5mg/kg ***Propofol*** at a rate of 20-40mg every 10 seconds or gaseous e.g. ***Nitrous oxide*** with O2 if airway obstruction or difficult IV access. * ***Airway control*** – use a face mask, oropharyngeal (Guedel) airway or intubation. The latter option will usually require muscle relaxation with a neuromuscular blocker. * ***Maintenance of anaesthesia*** – with either a volatile agent added to a N2O/O2 mixture, high dose opiates with mechanical ventilation or an IV infusion e.g. 4-12mg/kg/hour IV Propofol. * ***End of anaesthesia*** – change inspired gases to 100% oxygen, disconnect any anaesthetic infusions and reverse muscle paralysis. Once breathing spontaneously put the patient in the recovery position and give oxygen via a face mask.
28
Complications of Anaesthesia
Caused by loss of : * ***Pain sensation*** – urinary retention, diathermy burns, pressure necrosis or local nerve injuries e.g. a radial nerve palsy from arm hanging over the surgical table edge leading to wrist drop. * ***Consciousness*** – patient cannot communicate e.g. wrong leg or kidney or the problem may be retained consciousness – this can lead to neuroses or post-traumatic stress disorder. * ***Muscle power*** – corneal abrasion (tape the eyes closed), no respiration and no cough (leads to pneumonia or atelectasis – partial lung collapse which can occur minutes after induction).
29
The Analgesic Ladder
If one drug fails to relieve pain ***move up the ladder***: * ***Rung 1*** – non-opioid analgesia – e.g. paracetamol, non-steroidal anti-inflammatories or aspirin. * ***Rung 2*** – weak opioid analgesia – e.g. codeine, dihydrocodeine or tramadol. * ***Rung 3*** – strong opioid analgesia – e.g. morphine, diamorphine, oxycodone or fentanyl.
30
Non-narcotic (simple) Analgesia
There are many options including 0.5-1g ***Paracetamol*** PO every 4 hours (up to 4mg daily – caution in liver impairment), 400mg ***Ibuprofen*** PO TDS or 50mg ***Diclofenac*** PO TDS (caution in asthma, renal or hepatic impairment, pregnancy and the elderly) or ***Aspirin*** (not given to children as causes Reye syndrome – acute encephalopathy and fatty degeneration of the liver).
31
Opioid Analgesia
* ***Oral*** ***Morphine*** – start with 5-10mg oral solution every 4 hours – patient’s needs vary and there’s no max dose. Once daily needs known divide by 2 and give as modified release preparation (MST 12h). * ***If oral route unavailable*** – give IV or SC ***diamorphine***. ***Oxycodone*** is a newer more potent opioid with fewer side effects and can be given PO, IV, SC or PR. There are also ***fentanyl*** transdermal patches which should be changed every 72 hours and placed in a different area.
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Opioid Side Effects
***Common*** and can include drowsiness, nausea and vomiting (treat with prochlorperazine), constipation, dry mouth, respiratory depression, urinary retention or hypotension. Hallucinations and myoclonic jerks are signs of toxicity – treat with ***naloxone***.
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Pain Control - Adjuvants
E.g. radiotherapy for ***bone cancer pain***, anticonvulsants, antidepressants, gabapentin or steroids for ***neuropathic pain***, antispasmodics e.g. 10-20mg Buscopan PO, IM or IV TDS for intestinal or renal ***colic pain***. If ***brief pain relief*** is required e.g. for changing dressings or exploring wounds try inhaled nitrous oxide (with 50% O2 as Entonox).