Anaesthetics COPY Flashcards
Propofol.
MoA:
Adverse effects:
Extra effect:
Potentiates GABA
Pain on injection, HYPOTENSION
Anti-emetic
Thiopental
MoA:
Adverse effects:
Extra effect:
Barbiturate (potentiates GABA)
Laryngospasm
High soluble = quick effect on the brain
Etomidate
MoA:
Adverse effects:
Extra effect:
Potentiates GABA
Primary ADRENAL SUPPRESSION Myoclonus
Causes less hypotension than propofol and thiopental and therefore used in cases of haemodynamic instability
Ketamine
MoA:
Adverse effects:
Extra effect:
Blocks NMDA receptors
Disorientation, hallucinations
Acts as a DISSOCIATIVE ANAESTHETIC
No drop in BLOOD PRESSURE so useful in trauma.
Duration of time of cessation before surgery: ACEi LMWH Warfarin Anti-platelet
ACEi = 24 hours LMWH = 24 hours Warfarin = 5 days Anti-platelet = 7 days (week)
Majority cardiac drugs do not need stopped apart from ACEi - risk of AKI
Anti-coagulation
Warfarin stopped 5 days before - what are high risk pts. bridged with
Heparin
Pre-operative INR Mx.
INR < 1.5
INR 1.6-1.7
INR >1.8
proceed as normal
1 mg Vit K
2 mg Vit K
General anaesthesia
Induction agent
Muscle relaxant
Propofol, thiopental
Muscle relaxants: rocuronium, vecuronium, suxamethonium
Class of drugs of muscle relaxant
nACH antagonists
Reverse anaesthetic agent
Neostigmine
Mx. bradycardia
IV Atropine 500mcg
Mx. Hypotension
Vasopressors:
Ephedrine -> A&B agonist
Metaraminol -> a1
Mx. Malignant hyperthermia
IV Dantrolene
What is Mendelson syndrome
Aspiration of stomach acid causing inflammation of the lungs
Mx. Pre-operative RANITIDINE
Local anaesthetics
Long acting
Short acting
Lidocaine
Bupivacaine
Local anaesthetics use as epidural anaesthesia SE?
Hypotension, CVS collapse if given IV
Adrenaline with local anaesthetics - areas of the body where these cannot be used:
Fingers
Ears
Nose
Opioid overdose
Px.
Antidote.
Pin point pupils.
Respiratory depression
Reduced LOC drowsiness, coma.
Naloxone
400mcg bolus for OD
titred infusion for toxicity
BDZ overdose
Px.
Antidote.
Ataxia.
Dysarthria
Reduced LOC drowsiness, coma
Flumazenil
Aspirin overdose
Px.
Antidote.
Tinnitus.
Vomiting.
Dehydration.
Hyperventilation respiratory alkalosis (early) and (later) metabolic acidosis (anion gap)
Nil. Activated charcoal Supportive care + fluids. Bicarbonante infusion
B Blocker overdose
GLUCAGON
Salbutamol overdose
Agitation.
Tremor.
Tachycardia, palpitations.
Bloods: hypokalemia.
Nil
Tricyclics overdose
Px.
Mx.
Dilated pupils. Urinary retention. Dry mouth / skin. Ataxia w/ jerky movements and increased tone. ECG: sinus tachycardia.
Nil.
Supportive care +
• fluids.
Bicarbonante infusion.
Anti-freeze
Px.
Mx.
Ataxia, dysarthria, nausea, vomiting, convulsions, coma.
Diagnostic test: osmol gap on serum osmolality.
Mx. Fomepizole
Paracetamol overdose
Toxic dose.
Mx:
tx threshold: mg
> 150mg / kg.
N-Acetylcysteine should be given if:
there is a staggered overdose (not taken within 1 hour) or there is doubt over the time of paracetamol ingestion, regardless of the plasma paracetamol concentration; or
the plasma paracetamol concentration is on or above a single treatment line joining points of 100 mg/L at 4 hours and 15 mg/L at 15 hours, regardless of risk factors of hepatotoxicity.
100 mg
Cardiac arrest - 4Hs and 4Ts
Hypothermia
Hypovolaemia
Hypoxia
Hypo/hyperkalemia
Toxins
Tension pneumothorax
Tamponade
Thrombosis
Cardiac arrest - drugs
10 ml 1:10000 Adrenaline IV -> every 3-5 minutes
300 mg Amiodarone - after every 3 shocks
Cardiac arrest - bloods
FBC, U&E, LFTs, CRP, Magnesium, coagulation, ABG (or venous gas if this not possible)
Pathophysiology of shock (general)
• Shock is generalized tissue hypo perfusion and hypoxia due to acute circulatory failure.
• Blood pressure: TPR X CO.
• Failure to maintain MAP results in slow flow of blood through vessels which causes:
o Thrombus formation.
o Inadequate tissue perfusion, leading to a switch from aerobic to anaerobic respiration -> lactic acid accumulation and acidosis.
o Lactic acidosis reduces tissue function leading to injury, necrosis and multi-organ failure.
Lactate level in shock
> 2.2
Cardiogenic shock px
chest pain, palpitations + cold, clammy peripheries
Obstructive shock causes and px.
Causes: PE, tension pneumothorax, cardiac tamponade.
Cold clammy peripheries, distended neck veins, Raised JVP.
Hypovolaemic shock px. and mx.
Cold peripheries, dry mucous membranes, thready pulse, LOW JVP
Initial management = fluid challenge
Distributive shock cause and px.
Sepsis, anaphylaxis, neurogenic or spinal cord damage.
FEVER, warm flushed peripheries with increased capillary refill time.
Adult anaphylaxis - drug doses
Adrenaline 0.5ml/mg 1:1000 IM -> repeat every 5 minutes
Hydrocortisone: 200 mg slow IV
Chlorphenamine: 10 mg slow IV
Adult bradycardia
•Main drug: 500mcg Atropine IV. •If initial atropine doesn’t work, can give either of the following: -Repeat Atropine up to 6 times (3mg). -Isoprenaline 5mcg IV. -Adrenaline 2 – 10mcg IV. -Transcutaneous wiring.
Adult tachycardia w/ pulse:
•Amiodarone: o300mg IV over 10 – 20 minutes. o900mg IV over 24 hours. oIndications: Three failed DC shocks in unstable patient. Regular broad complex tachycardia.
•Adenosine:
oInitial: 6mg IV bolus.
o can give up to two further 12mg boluses if no effect.
oIndications: failed vagal maneuvers in regular narrow complex.
Cushings reflex (3) Bodys natural way to overcome raised ICP by increasing blood pressure.
Bradycardia + hypertension + irregular breathing
GCS =
MVE 6,5,4
Obeys commands. 6 Localizes to pain. 5 Flexion & withdrawal to pain. 4 Abnormal flexion to pain. 3 Extension to pain. 2 No response. 1
Orientated and talking. 5 Confused and disoriented - 4 Inappropriate words 3 Incomprehensible sounds 2 No verbal response 1
Opens spontaneously. 4
Opens to command. 3
Opens to pain. 2
No response. 1
GCS < 14 px.
Confused and disorientated
GCS < 8
Comatose
GCS 3
Completely unresponsive
Head injury bruising: what causes ‘panda eyes’ appearance
Anterior fossa fracture: Bilateral periorbital
‘Battle sign’
Middle fossa
Mastoid bruising behind the ear
What bone do middle fossa fractures encompass and how can this present -
Temporal bone
SNHL, facial nerve palsies
Think about the course of cranial nerves
Head injury initial assessment
ABCDE, GCS, ALWAYS DO A BLOOD GLUCOSE
Examination: cranial, upper/lower limb neuro
Head injury investigations
Bloods: FBC, U&E, LFT, coagulation, cross match, glucose.
CSF sample: positive for glucose / B2 tau protein.
CT head indications:
o GCS < 13 on initial assessment.
o GCS < 15 at 2 hours on assessment in ED.
o Suspected skull fracture.
o Posttraumatic seizure.
o Focal neurological deficit.
o More than one episode of vomiting since injury.
o LOC or amnesia if >65, risk of bleeding or >30 minutes of memory loss.
Raised ICP tx.
Usually neurosurgical
Holding measures: Mannitol, Sedation, intubation, hyperventilation
Facial trauma - blow out fracture px.
Inferior rectus entrapment =
Red eye, recessed eye, double vision - reduced eye movements -> cannot look up
ipsilateral nose bleed
loss of sensation of CNV2
X-ray blow out fracture appearance:
Tear-drop sign on X-ray
American society of Anaesthetics classifications (I-VI)
I = normal healthy pt. II = A patient with MILD systemic disease III = A patient with severe systemic disease IV = severe systemic disease which is a constant threat to life V = Moribund pt. who is not expected to survive VI = DEAD
Blood transfusion - action
Unlikely (Hysterectomy, appendicectomy, thyroidectomy, lap cholecystectomy) =
Likely (salpingectomy for ruptured ectopic pregnancy, THR) =
Definite (Total gastrectomy, oophorectomy, oesophagectomy, elective AAA repair, cystectomy, hepatectomy) =
Group and save
Cross match 2 units
Cross-match 4-6 units
Nitrous oxide - MoA, Adverse effects, Notes
MoA = Unknown
Adverse effects = may diffuse into gas-filled compartments - to be avoided in pneumothorax
Notes = used for maintenance analgesia and anaesthesia
Volatile liquid anaesthetics (Isoflurane, Desflurane, Sevoflurane) adverse effects
Myocardial depression
Malignant hyperthermia
Halothane (not common now = hepatotoxic)
Peripheral venous cannulas - pros and cons
Pros = easy to insert, wide lumen can provide rapid infusion. Cons = problems with peripheral sites for vasoactive drugs - such as inotropes and irritant drugs.
Central line Ps and Cs
Preferred route - IJV or Femoral ?
Multiple lumens for allowing multiple infusions -
Lumens are narrow though so do not allow for rapid infusion
IJV (femoral lines have higher infection rates).
Tunnelled lines (Hickman, Groshong)
Devices inserted using US guidance into IJV then tunnelled. For long term therapeutic requirements.
PICC (peripherally inserted central cannula) - Ps and CS
Less prone to major complications relating to device insertion than conventional central lines.
Lidocaine toxicity features and tx.
Features = initial CNS over activity followed by depression as lidocaine blocks inhibitory pathways. Cardiac arrhythmias.
Local anaesthetic toxicity is treated with IV 20% lipid emulsion
Bupivacaine - duration of action relative to Lidocaine, SE, CI
Longer, cardiotoxic, contraindicated in regional blockage in case the tourniquet fails
Malignant hyperthermia: causative drugs
Treatment?
Halothane
Suxamethonium
Anti-psychotics (Neuroepileptic malignant syndrome)
Dantrolene
Muscle relaxants - Suxamethonium MOA and adverse effects, onset and duration?
DEpolarizing neuromuscular blocker - cannot be reversed consequently.
produces generalised contraction prior to paralysis
Adverse effects = Hyperkalaemia, malignant hyperthermia and lack of acetylcholinesterase.
FASTEST ONSET AND SHORTEST DURATION OF ALL MUSCLE RELAXANTS
Muscle relaxants - Atracurium MOA and adverse effects, reversed by?
NON-depolarizing neuromuscular blocker
May cause facial flushing, tachycardia and hypotension due to generalised histamine release.
reversed by neostigmine
Muscle relaxants - Vecuronium MOA and adverse effects, reversed by?
NON-depolarizing neuromuscular blocker
Degraded by liver and kidney and effects prolonged in organ dysfunction.
reversed by neostigmine
Muscle relaxants - Pancuronium MOA and adverse effects, reversed by
NON-depolarizing neuromuscular blocker
Onset = 2-3 minutes
PARTIALLY reversed by neostigmine
Suxamethonium contraindication - (EYE)
Patients with penetrating eye injuries or acute closed angle glaucoma as suxamethonium increases intra ocular pressure.
TPN long term associations
Fatty liver and derranged LFTs
Feeding Jejunostomy - can this be used for long term feeding? Risk of aspiration? Main risks?
Yes, low, main risks are tube displacement and leaking carrying as risk of peritonitis
Naso-gastric feeding contraindication
Head injury - risks associated with tube insertion
Post-operative pyrexia
Early (0-5 days) causes :
Late (>5 days) causes :
Early (0-5 days) causes : Blood transfusion, cellulitis, UTI, Physiological systemic inflammatory reaction, pulmonary atelectasis
Late (>5 days) causes : VTE, Pneumonia, wound infection, anastamotic leak.
Post-operative illeus cause and mx -
Causes = deranged electrolytes can contribute to the development of post-operative ileus - important to check potassium, magnesium and phosphate.
mx = NBM initially, NG tube if vomiting, IV fluids to maintain normovolaemia - additives to correct electrolyte imbalances
TPN occasionally for severe/ prolonged cases.
Preparation for surgery - oral fluids and fasting rules
Pts. may drink CLEAR (water, fruit juices without pulp, coffee/tea without milk) fluids until 2 hours before their operation. (can help reduce headaches etc. post-operatively)
Pts. Generally advised to fast from foods and non-clear fluids from 6 hours before surgery
Post-operative risks for diabetic pts. (3)
Increased wound and respiratory infections
Increased risk of post-operative AKI
Increased length of hospital stay
Do patients <69 HbA1c (good diabetic control) require anything more than adjustment of usual insulin regimen post-surgery
NO
Can most oral-therapy diabetics (T2) be managed by manipulating medication on the day of surgery?
What are exceptions to this ?
What should be used in this case ?
Yes
Exceptions: If more than one meal is to be missed
Poor glycaemic control
Risk of renal injury (low eGFR, Contrast)
in which case VRIII (variable release intravenous insulin infusion should be used)
Rules for metformin:
Day prior to admission
Day of surgery (morning op) :
Day of surgery (afternoon op) :
Day prior to admission : Take as normal
Day of surgery (morning op) : if taken once/twice a day - take as normal -> If taken 3/day - omit lunch dose.
Day of surgery (afternoon op) : if taken once/twice a day - take as normal -> If taken 3/day - omit lunch dose.
Rules for Sulphonylureas (Gliclazide):
Day prior to admission
Day of surgery (morning op) :
Day of surgery (afternoon op) :
Rules for Sulphonylureas (Gliclazide)
Day prior to admission : Take as normal
Day of surgery (morning op) : If taken once daily, omit dose that day - if 2/day omit morning dose
Day of surgery (afternoon op) : If taken once daily, omit dose that day - if 2/day omit BOTH doses that day.
Rules for DDP IV Inhibitors (GLIPTINS)
Day prior to admission
Day of surgery (morning op) :
Day of surgery (afternoon op) :
Take as normal
Rules for GLP-1 analogues (-tides)
Day prior to admission
Day of surgery (morning op) :
Day of surgery (afternoon op) :
Take as normal
Rules for SGLT-2 inhibitors
Day prior to admission
Day of surgery (morning op) :
Day of surgery (afternoon op) :
Day prior to admission: take as normal
Day of surgery (morning op) : omit on day
Day of surgery (afternoon op) : omit on day
Rules for once daily insulins (Lantus, Levemir)
Day prior to admission
Day of surgery (morning op) :
Day of surgery (afternoon op) :
Day prior to admission: REDUCE BY 20%
Day of surgery (morning op) : REDUCE BY 20%
Day of surgery (afternoon op) : REDUCE BY 20%
Twice-daily biphasic
Day prior to admission: No dose change
Day of surgery (morning op) : Reduce morning dose by half, evening unchanged (50%).
Day of surgery (afternoon op) : Reduce morning dose by half, evening unchanged (50%).
Special preparations: PTH surgery - Sentinel node biopsy Surgery of thoracic duct Phaeochromocytoma surgery Surgery for carcinoid tumours colorectal cases Thyrotoxicosis
Thyroid surgery; vocal cord check.
Parathyroid surgery; consider methylene blue to identify gland.
Sentinel node biopsy; radioactive marker/ patent blue dye.
Surgery involving the thoracic duct; consider administration of cream.
Pheochromocytoma surgery; will need alpha and beta blockade.
Surgery for carcinoid tumours; will need covering with octreotide.
Colorectal cases; bowel preparation (especially left sided surgery)
Thyrotoxicosis; lugols iodine/ medical therapy.
Surgical complications: Accessory: Sciatic: Common peroneal: Long thoracic: Pelvic autonomic nerves: Recurrent laryngeal nerves: Hypoglossal nerve: Ulnar and median nerves:
Accessory Posterior triangle lymph node biopsy
Sciatic Posterior approach to hip
Common peroneal Legs in Lloyd Davies position
Long thoracic Axillary node clearance
Pelvic autonomic nerves Pelvic cancer surgery
Recurrent laryngeal nerves During thyroid surgery
Hypoglossal nerve During carotid endarterectomy
Ulnar and median nerves During upper limb fracture repairs
Surgical complications: Thoracic duct Pneumonectomy, Oesphagectomy Parathyroid glands Ureters Bowel perforation Bile duct injury Facial nerve Tail of pancreas Testicular vessels Hepatic veins
Thoracic duct: During thoracic surgery e.g. Pneumonectomy, oesphagectomy
Parathyroid glands: During difficult thyroid surgery
Ureters: During colonic resections/ gynaecological surgery
Bowel perforation: Use of Verres Needle to establish pneumoperitoneum
Bile duct injury: Failure to delineate Calots triangle carefully and careless use of diathermy
Facial nerve: Always at risk during Parotidectomy
Tail of pancreas: When ligating splenic hilum
Testicular vessels:
During re-do open hernia surgery
Hepatic veins: During liver mobilisation
Ix for intra-abdominal abscess, air and if luminal contrast is used, anastomotic leak?
CT scan
Ix for rectal anastamotic leaks
Gastograffin enema
Ix. Leg veins - for DVT
Doppler USS
Ix. PE
CTPA
Recent surgery - CI for thrombolysis? mx.
Yes, IV heparin preferable to heparin - easier to reverse.
Complications of perioperative hypothermia
Coagulopathy: reduced ability to clot, increasing intra-operative blood loss.
Prolonged recovery from anaesthesia.
Reduced wound healing
infection
shivering= benign in healthy individuals but cab cause increase in metabolic rate which can result in myocardial ischaemia.
Risk factors for peri-operative HYPOthermia
- ASA 2 or above
- Major surgery
- low body weight
- large volumes of unwarmed IV infusions
- unwarmed blood transfusions
Risks VTE
Medical and trauma patients
Significant reduction in mobility for 3 days or more
Hip/knee replacements
Hip fracture
Pelvic surgery
acute surgical admission for inflammatory/intra-abdominal condition
general risk factors VTE
- Active cancer/ chemotherapy
- aged > 60
- known clotting disorder
- BMI > 35
- Dehydration
- HRT
- COCP
- varicose veins
- pregnant/ less than 6 weeks post-partum
VTE prophylaxis - medical
Fondaparinux (SC injection)
LMWH - reduced doses in pts. with severe renal impairment
Unfractioned heparin - alternative to LMWH in pts. with chronic kidney disease
When should women on COCP stop pill before surgery?
4 weeks
VTE prophylaxis for pts. with fragility fracture -
LMWH (6-12 hours post-op) or Fondaparinux for a month
Hypertrophic vs keloid scars
Hypertrophic remains confined to the boundaries of the original wound.
Keloid = extend outwith boundaries - do not regress over time.
Drugs impairing wound healing
- Non-steroidal anti-inflammatory drugs
- Steroids
- immunosupressive agents
- Anti-neoplastic drugs
