When should the following be stopped preop? 1. water 2. clear fluids (black coffee, tea) 3. breast milk 4. all other (chewing gum, milk etc.) 5. alcohol

1. water - 30mls with tablets allowed 2. clear fluids (black coffee, tea) - >2hrs 3. breast milk >4hrs 4. all other (chewing gum, milk etc.) >6 hrs 5. alcohol >24 hrs

Anaes 1 Flashcards by Joe Smith

What are main parts of the pre-operative assessment?

History of PC
Surgical, anaesthetic and medical history
Systems review
Drug history and allergies
Social : smoking, weight and exercise tolerance

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What is Mallampati? grades?

How much of soft palate is visible on looking into open mouth

Grade 1 : soft palate, uvula, fauces and pharyngeal pillars

Grade 2 : soft palate, uvula, fauces

Grade 3 : soft palate, base of uvula

Grade 4 : hard palate

3/4 would be difficult intubation

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What is thyromental distance?

Measure from upper edge of thyroid cartilage to chin with the head fully extended

Normal is approx. : 7cm

6-6.5cm - difficult laryngoscopy

<6cm - laryngoscopy may be impossible

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What is the sternomental distance?

SAVVA test

Distance from the upper border of the manubrium to the tip of the mentum, neck fully extended, mouth closed

Minimal acceptable value = 12.5 cm

*single best predictor of difficult laryngoscopy and intubation

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What would be relevant diseases in PMH to check?

Cardiovascular : chest pain, palpitations, SOBOE, syncope, orthopnoea, FHx of CVD

Respiratory : SOB, cough, infections, wheeze, asthma, COPD, obstructive sleep apnoea, smoker

GI : reflux, heartburn, liver/renal disease

Misc. : diabetes, CVA, epilepsy, issues with cervical spine/RA/OA

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What is the ASA score? Components?

American Society of Anaesthesiologists score - classification system is a system for assessing the fitness of patients AT TIME of surgery

1 : normally healthy
2 : Mild systemic disease, lo limitation of activity
3: Severe systemic disease, limitation of activity, not incapacitating
4 : Incapacitating systemic diseases which poses a threat to life
5 : Moribund, not expected to survive 24 hrs even with operation
6: brain dead patient whose organs are being removed for donor purposes

*suffix E denotes emergency

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What is the NCEPOD classification?

The NCEPOD Classification of Intervention. Acute onset or deterioration of conditions that threaten life, limb or organ survival

Immediate - minutes - AAA rupture, control of haemorrhage, coronary angioplasty
Urgent - hours - debridement and fixation of fracture, bowel perforation
Expedited - days - tendon and nerve injuries, excision of tumour with potential to obstruct
Elective - planned - elective surgery

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What would you be the approach towards steroids and diuretics pre-operative?

Steroids - contrinue intra and post-op due to adrenocortical suppression

Diuretics : stop a day before surgery if recently started as risk of hypovolaemia

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What would you be the approach towards ACE-I and B-blockers pre-operative?

ACEi : stopped if major surgery or if blood loss anticipated

B-blockers : always continues as decrease heart rate = tachycardia decreases diastolic time, reduces O2 delivery to heart and increases risk of MI

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What would you be the approach towards Diabetes and warfarin pre-operative?

metformin stopped morning of surgery - patient should be first on list, insulin on sliding scale

Warfarin : stop 4/7 before surgery, risk of bleeding minimal if INR <1.5

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What would you be the approach towards COCP pre-operative?

stop 4/52 before

bridge with POP

start 2/52 after (risk of DVT)

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When should the following be stopped preop?

water
clear fluids (black coffee, tea)
breast milk
all other (chewing gum, milk etc.)
alcohol

water - 30mls with tablets allowed
clear fluids (black coffee, tea) - >2hrs
breast milk >4hrs
all other (chewing gum, milk etc.) >6 hrs
alcohol >24 hrs

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What risk does inadequate fasting pose?

Risk of pulmonary aspiration

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What are some common risks of anaesthesia?

Postop N&V

Dizziness

Blurred vision

Aches/pains
Bladder problems

sore throat

damage to lips

confusion

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What are some uncommon risks of anaesthesia?

slow breathing

worsening of existing medical conditions

chest infections

damage to teeth

awareness during operation

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What are some rare risks of anaesthesia?

damage to eyes

MI, stroke

serious allergy

nerve damage

death

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What are some reasons for cancellation of operation?

current resp tract infection

poor control of drug therapy

recent MI : 3/12

bloods - K+ imbalance, anaemia

inadequate prep : results not available, not crossmatches, not fasted

logistics : insufficient ICU beds, staff, theatre time

What is your management post-op?

stop anaesthetic vapours
give O2
throat suction
reverse muscle relaxation

Once breathing : inspect mouth, remove ET tube, O2 by facemask

recovery

What are some risk factors for post op N&V?

Female, Previous PONV, anxious, motion sickness, non-smoker, obesity

Anaesthesia : opiates, etomidate, NO2, volatile agents, dehydration

Surgery :laparotomy, gynae, abdo, neuro, ENT, eye

How can you manage post op N&V?

Intra-op - ondansetron, dexamethasone

Post-op - cyclizine

Acupuncture point P6

Complications of post-op N&V?

Dehydration

Electrolyte imbalance

Metabolic alkalosis

Pulmonary aspiration

Incisional hernia formation

Damage to surgery site

Inability to take PO meds

What routes can local anaesthetics be administered?

Tissue infiltration : around incision

Peripheral nerve block : femoral

Plexus block : brachial

Epidural/spinal

Topical : EMLA

Mucosal : ENT procedures

What are some names of local anaesthetics?

Lidocaine

Bupivocaine/Levobupivacaine

Prilocaine

Why is adrenaline used with local anaesthetics? When should it be avoided?

anaesthetics cause vasodilation : Vasoconstricts via alpha adrenergic receptor

Decreases blood loss

Increases duration of anaesthesia

Decreases toxicity (delays absorption of LA)

don’t use in END ORGANS - fingers, toes, nose, ears, penis = ischaemia and necrosis
avoid in HTN, IHD, peripheral vascular disease, thyrotoxicosis, phaeochromocytoma. b-blockers

How would local anaesthetic toxicity present?

If rise is slow : then CNS effected first - excitatory (inhibition of GABA) : perioral and tongue paraesthesia, metallic taste, dizziness, slurred speech, diploplia, tinnitus, confusion, restlessness Cardiovascular toxicity : tachycardia, hypertension then hypotension and bradycardia, heart block, ventricular arrhythmias, cardiac arrest If high plasma levels, widespread Na+ channel blockage : generalised neuronal depression = coma, resp arrest, cardiac arrest

How would you manage anaesthetic toxicity?

Starts to occur 10-25 mins after ABC D : control seizures : (benzos/thiopentone/profolol) E : Intralipid IV : 20 % lipid emulsion = binds LA, reduces free radicals, should be on crash trolleys or should be in theatres

Increased risk of anaesthetic toxicity?

``` small children and elderly heart block low cardiac output epilepsy myasthenia gravis hepatic impairment anti-arrhythmic or beta-blocker cimetidine (inhibits metabolism of lidocaine) ```

What are differences between main local anaesthetics?

Lidocaine - 30-60mins or 90 w/ lidocaine Bupivacaine - 3-8hrs, but onset slower than lidocaine Prilocaine - 30-60mins, useful for Bier's block (Colles' fracture) Tetracaine/Proxymetacaine - topical local of the cornea

Where would you administer spinal anaesthesia? How long does it last?

Small volume directly into CSF - subarachnoid space - aim to inject between L2/S2 - below L4/5 is fused really Anaesthesia duration : 2-3 hrs analgesia duration longer

Where would you administer epidural anaesthesia? How long does it last?

Below L1 unless laparotomy (thoracic level) - epidural space - larger amount as must cross dura Duration titratable for 72 hrs

What are some risks involved with a total spinal block?

``` Hypotension Bradycardia Anxiety Apnoea Loss of consciousness Death from asphyxia ```

Contraindications for spinal/epidural anaesthesia?

``` Anticoagulant states local sepsis shick hypovolaemia raised ICP fixed output (aortic stenosis) neurological disease ```

What does the MK doctrine state?

Cranium is incompressible and volume inside is fixed Increase in volume in one of cranial constituents (blood, CSF, brain) must be compensated by decrease of another Main buffer for increase are CSF or blood = normal ICP for change in volume of up to 120ml

How does cranial perfusion pressure related to mean arterial pressure and intracranial pressure?

CPP = MAP - ICP As ICP increases, CPP decreases body compensates by increasing BP to maintain MAP to maintain CPP

Formula for MAP?

Diastolic +(1/3 of systolic - diastolic)

What are some signs of raised ICP?

headache : worse in morning, coughing, bending down Vomiting : without nausea Eyes : papilloedema, dilated pupils, impaired eye movements Cushing's triad : increased systolic BP, bradycardia, Cheyne-Stokes resp Personality/behaviour changes

How would you manage raised ICP?

Improve CSF drainage : elevated head, neck straight, improves jugular venous outflow intraventricular catheter : monitors ICP but can drain CSF Oxygenation and ventilation : hyperventilation lowers ICP (hypocapnoeic vasoconst) Analgesia and sedation neuromuscular bloackade - reduced ICP by avoiding coughing Mannitol : intravascular osmotic agent - decreases blood viscosity

What are crystalloids? Examples?

Salts dissolved in water to form ionic solutions, compounds can pass across semi-permeable membrane iso/hyper/hypo solutions NaCl, dextrose, dex-saline, Hartmann's

What are colloids?

Large chemicals (proteins/starches) incapable of passing across semi-permeable membranes Stay in circulation: increases oncotic pressure, causes volume expansion contents like gelatin : can leak out of capillaries = small risk of allergies

What should we take into account when classifying hypovolamic shock?

``` Blood loss Pulse rate BP Cap refill Resp Rate Urinary Output Mental status ```

What is the sepsis six protocol?

Oxygen sats to atleast 94% Blood cultures and consider source control Administer empiric abx Measure serial serum lactates Start IV resus Measure urine output