Corrections - Anaesthetics Flashcards by Esme Cosham

What is suxamethonium apnoea?

There is a deficiency in the enzyme that breaks down suxamethonium –> can lead to prolonged airway paralysis (can be several hours when normal time of sux. apnoea is 5 minutes).

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Length of action of suxamethoium?

2-6 minutes

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Mechanism of suxamethonium?

Mimics acetylcholine at the neuromuscular junction, binding to the post-synaptic membrane of the junction (preventing acetylcholine from binding).

NON-competitive binding.

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Can suxamethonium be reversed?

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Can non-depolarising muscle relaxants be reversed?

Yes:

1) cholinesterase inhibitors e.g. neostigmine

2) sugammadex

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Effect of anticholinesterases such as neostigmine on suxamethonium?

These PROLONG the action of suxamethonium.

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Presentation of suxamethonium apnoea?

Usually not apparent until it is time to wake the patient up.

At the end of the procedure the patient:

makes little effort to cough or breathe spontaneously
HR and BP rise
may sweat
pupils may dilate

This happens because the patient becoming aware but
is still paralysed.

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Management of suxamethonium apnoea?

1) Neuromuscular
transmission should be monitored with a nerve stimulator.

2) Keep patient anaesthetised and ventilated.

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Cause of suxamethonium apnoea?

Pseudocholinesterase deficiency

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What type of respiratory failure can MND cause?

Type 2 (poor ventilation due to muscle weakness, leading to a build up of carbon dioxide and an acidosis).

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What reading is used to confirm intubation?

End-tidal CO2

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What are some signs of a basal skull fracture?

1) Periorbital ecchymosis (raccoon eyes)

2) CSF rhinorrhoea

3) Haemotympanum (presence of blood in the middle ear cavity)

4) Mastoid process bruising (battle’s sign).

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What do dropping sats post-intubation indicate?

Oeseopageal intubation

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What complication can long-term intubation result in?

Can result in physical communication between the trachea and the oesophagus due to the proximity of the structures and inflammation around the tube in the trachea –> tracheo-esophageal fistula.

Presents with choking after feeds.

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What is the max number of doses of IV benzos that can be administered during convulsive status epilepticus?

A maximum of two doses

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What is the only available specific and effective treatment for malignant hyperthermia?

IV dantrolene

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What ASA grade is a patient who is a smoker but no medical conditions?

ASA II

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What ASA grade is a patient who is a social alcohol drinker but no medical conditions?

ASA II

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What ASA grade is a patient who has a BMI of 30-40?

ASA II

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What ASA grade is a patient who has a BMI of >40?

ASA III

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What ASA is a patient with well-controlled Diabetes Mellitus or HTN or mild lung disease?

ASA II

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What ASA is a patient with poorly-controlled Diabetes Mellitus or HTN?

ASA III

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What ASA grade is a patient with COPD?

ASA III

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What ASA grade is a patient with alcohol dependence or abuse?

ASA III

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What ASA grade is a patient with an implanted pacemaker?

ACE III

What ASA grade is a patient with a history of MI (>3 months)?

ASA III

What ASA grade is a patient with end stage renal disease?

ASA III

What ASA grade is a patient with a history of MI (<3 months)?

ASA IV

What ASA grade is a patient with sepsis?

ASA IV

What ASA grade is a patient with a ruptured AAA?

ASA V

Mechanism of lidocaine?

Blockage of sodium channels, disrupting the action potential.

How do you calculate a BMI?

Weight (kg) / height (m2) E.g. man weighs 100kg and is 170cm tall 100 / 1.70^2 = 34.6

Where should a patient with diabetes be put on the operating list of the day?

Patient should be put first on the list to prevent complications of poor glucose control.

What investigations may be considered prior to elective surgery?

1) Consider pre admission clinic to address medical issues. 2) Blood tests including FBC, U+E, LFTs, Clotting, Group and Save 3) Urine analysis 4) Pregnancy test 5) Sickle cell test 6) ECG/ Chest x-ray

During an A-E situation, if you cannot get peripheral IV access within 2 minutes of presentation, what should you do?

Call a trained individual to attempt intraosseous access.

What is a potential, and serious, cause of new onset atrial fibrillation following gastrointestinal surgery?

An anastomotic leak

How soon post-op does an anastomotic leak usually present?

5-7 days post-op

How can an anastomotic leak cause post-op AF?

Can cause systemic inflammation, which sensitises the pacemaker cells.

How can an anastomotic leak be diagnosed?

Abdominal CT

When should COCP be stopped prior to surgery?

4 weeks

Mechanism of depolarising neuromuscular blocking drugs?

Binds to nicotinic acetylcholine receptors resulting in persistent depolarisation of the motor end plate.

Mechanism of non-depolarising neuromuscular blocking drugs?

Competitive antagonist of nicotinic acetylcholine receptors

Examples of non-depolarising neuromuscular blocking drugs?

Tubcurarine, atracurium, vecuronium, pancuronium

What are the 2 key adverse effects of suxamethonium (Succinylcholine) i.e. a depolarising neuromuscular blocking drug?

1) Malignant hyperthermia 2) Hyperkalaemia (normally transient)

What is the key adverse effect of non-depolarising neuromuscular blocking drugs?

Hypotension.

Reversal agent of suxamethonium?

None

Reversal agent of non-depolarising neuromuscular blocking drugs??

Acetylcholinesterase inhibitors (e.g. neostigmine).

What is the muscle relaxant of choice for rapid sequence induction (RSI) for intubation?

Suxamethonium

Give 2 contraindications for suxamethonium

1) penetrating eye injuries 2) acute narrow angle glaucoma As suxamethonium increases intra-ocular pressure (IOP).

Are CXRs routinely recommended before surgery?

Which 4 classes of drugs impair wound healing?

1) NSAIDs 2) Steroids 3) Immunosupressive agents 4) Anti neoplastic drugs

How should surgical wound be cleaned post-op?

Up to 48h post-op --> use sterile saline Over 48h post-op --> patient can shower

When should you consider a physiological systemic inflammatory reaction in post-op pyrexial patients?

Usually within a day following the operation AND no other signs of an underlying cause (e.g. BP, RR etc) i.e. fever is isolated. A fever in the first 24 hours is most likely the result of an inflammatory response to tissue damage as a result of surgery.

Which type of muscle relaxant can cause fasciculations?

Suxamethonium

Which drug can reverse the action of benzos?

Flumenazil. Since may benzodiazepines have longer half lives than flumazenil patients still require close monitoring after receiving the drug.

Management of post-op ileus?

1) NG tube insertion for stomach decompression (symptom control) 2) Nil by mouth

Management of local anesthetic toxicity can be treated?

IV 20% lipid emulsion

Management of warfarin prior to surgery in patients at high VTE risk?

Stop 6 days before and commence treatment dose LMWH (this would then be withheld the evening before surgery, and mechanical prophylaxis used).

What steroid can be used during the peri-op period for patients that are steroid dependent (i.e. >5mg prednisolone daily)?

Hydrocortisone

How many mg of lidocaine is there in 20ml of 2% lidocaine?

2% means that 2g/20mg of drug are dissolved in 100ml. 2 x 10 = 20 20 x 20 = 400mg

Why is Hartmann's chosen over saline where large volumes of fluids are to be administered?

As excessive administration of saline can cause hyperchloraemic acidosis.

What are early causes of post-op pyrexia (0-5 days)?

1) blood transfusion 2) cellulitis 3) UTI 4) physiological systemic inflammatory reaction (usually within a day following the operation) 5) pulmonary atelectasis

What are late causes of post-op pyrexia (>5 days)?

1) VTE 2) pneumonia 3) wound infection 4) anastomotic leak

What timeline can be used as a broad rule of thumb when determining the most likely causes of post-op fever?

Day 1-2: 'Wind' - pneumonia, aspiration, PE Day 3-5: 'Water' - UTI (especially if patient was catheterised) Day 5-7: 'Wound' - infection at surgical site or abscess formation Day 5+: 'Walking' - DVT or PE Any time: drugs, transfusion reactions, sepsis, line contaminations.

Management of a post-op anastamotic leak?

Call consultant and take patient straight to surgery

Via what line should total parenteral nutrition be delivered?

Via a central vein e.g. subclavian vein as it is strongly phlebitic.

For elective total hip replacement, when should LMWH be commenced?

6-12 hours after surgery

When should adrenaline alongside LA be avoided?

digits & penis as adrenaline can cause ischaemia in these settings

How should sulfonylureas (e.g. gliclazide) be managed on day of surgery?

Omit on day of surgery. Exception is morning surgery in patients who take BD - they can have the afternoon dose but omit morning.

At what site is interosseous access most commonly obtained?

Proximal tibia

What is the most appropriate management of insulin dependent diabetic patients who are: a) undergoing major procedures (surgery requiring a long fasting period of more than one missed meal) or b) whose diabetes is poorly controlled?

Will usually require a variable rate IV insulin infusion (VRIII).

What does the 'time out' stage of the WHO surgical checklist refer to?

The period from induction of anaesthetic but before the first skin incision is made

What are the 3 key stages of the WHO surgical safety checklist?

1) Sign in 2) Time out 3) Sign out

Management of metformin on day of surgery (in surgery in morning) : 1) in patients taking OD or BD 2) in patients taking TDS

1) take as normal 2) miss lunchtime dose

Why is suxamethonium contraindicated in penetrating eye injuries or acute narrow angle glaucoma?

As it raises intra-ocular pressure

What is there a deficiency of in suxamethonium apnoea?

Pseudocholinesterase

What must be given the day prior to a colonoscopy?

Laxatives

2ary prevention in ischaemic stroke (i.e. after 14 days)?

Clopidogrel + statin

What blood test can differentiate between a true seizure and a pseudoseizure?

Prolactin - levels are raised 10-20 mins after a true generalised tonic-clonic seizure

How can myasthenia gravis affect muscle relaxants? Why?

Patients with myasthenia gravis are very sensitive to non-depolarising agents. Non-depolarising agents work by antagonism of nicotinic acetylcholine receptors in the motor end plate, producing paralysis by their blockade. The myasthenic patient has fewer available nicotinic receptors due to autoimmune-mediated destruction, meaning that they are more sensitive to non-depolarising blockade.

What 2 conditions can increase susceptibility to non-depolarising muscle relaxants (e.g. rocuronium)?

1) Myasthenia gravis 2) Lambert-Eaton syndrome

How should insulin dose be adjusted on the day before and the day of surgery?

Note - this only applies to once daily long acting insulin. Once daily insulin dose should generally be reduced by 20% on the day before and the day of surgery

What is checked before the induction of anaesthesia (i.e. under the 'sign in' section)?

1) Patient has confirmed: Site, identity, procedure, consent 2) Site is marked 3) Anaesthesia safety check completed 4) Pulse oximeter is on patient and functioning 5) Does the patient have a known allergy? 6) Is there a difficult airway/aspiration risk? 7) Is there a risk of > 500ml blood loss (7ml/kg in children)?

What VTE prophylaxis is required in patients underoging an elective hip replacement?

Both mechanical and pharmacological methods of VTE prophylaxis. I.e.: 1) TED stockings once admitted 2) + LMWH (e.g. dalteparin sodium) - 6 hours post-op

Which feeding option has a low risk of aspiration and thus safe for long term feeding following upper GI surgery?

Feeding jejunostomy

How can poor post-op pain management result in pneumonia?

Significant pain can restrict patients to a shallow breathing pattern. Lack of deep breathing is a risk factor for both atelectasis and RTIs.

When does VTE typically present post-op?

5-10 days post-op

What IV access is indicated for patients with long term therapeutic requirements?

Tunnelled lines such as Groshong and Hickman lines

What is Milrinone?

A medication indicated for cardiac support in patients with acute heart failure, pulmonary hypertension, or chronic heart failure. Mechanism: phosphodiesterase 3 inhibitor. Action: works to increase the heart's contractility and decrease pulmonary vascular resistance

What class of medication is gabapentin?

Anticonvulsant

What class of medication is neostigmine?

Cholinesterase inhibitor Role - the reversal of the effects of non-depolarising neuromuscular blocking agents after surgery.