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102 Cards in this Set
- Front
- Back
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Common side effects of metaclopramide
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restlessnes, drowsyness, dizziness and headache
anxiety and agitation following IV administration |
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What makes acute dystonic reactions more common in patients taking metaclopramide?
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children and young adults- especially females
due to individual sensitivity or excessive dosing respond quickly to single dose of benztropine |
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How long does it take for parkinsonian reactions to resolve after withdrawal of metaclopramide?
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Months
rare |
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What is the mechanism of action of prochlorperazine?
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centrally mediated: blockage of dopamine receptors- anticholinerfic
postural hypotension and sedation prolonged use can cause tardive dyskinesia and parkinsonism |
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Mechanism of action of domperidone
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dopamine antagonist that blocks receptors in the CTZ + direct stimulator of gastric motility (not known if this contributes to its antiemetic properties)
May not be as effective as oral metaclopramide |
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Oral versus IV dose of morphine?
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oral 3x more
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Adverse effects of domperidone
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mild abdominal cramps, dry mouth and galactorrhea
acute extrapyramidal effects have been reported- although domperidone does not readily cross BBB |
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When are agents such as ondansetron effective in preventing post-op nausea and vomiting?
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when given at the end of surgery - less effective when given once nausea and comiting already established
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Side eddects of ondansetron?
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headaches and constipation are common
flushing and visual disturbances may occur especually if rapid IV |
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What is aprepitant?
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substance P antagonist (NK1 receptors in CNS)- contribute to nausea and vomiting in people getting chemotherapy
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Interaction between aprepitant and other drugs
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Inhibits CYP3A4- therefore have to decrease dose of dexamethasone by 50%
INR monitoring required by patients on warfarin |
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Mechanism of promethasine
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Sedating antihistamine with antimuscarinic effects-used to prevent and treat motion sickness and in post-op nausea and vomiting
in palliative care- use in centrally mediated nausea and vomiting and nausea and vomiting which resukts from bowel obstruction |
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When is dexamethasone useful in reducing post-operative nausea and vomiting?
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up to 24 hours post surgery
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What are the advantages of fentanyl for procedural sedation?
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reversible
minimal cardiovascular depression analgesia 2-3ug/kg IV |
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Advantages of ketamine for procedural sedation?
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reliable
very effective analgesia in subanesthetic doses dissociative effect airway reflexes maintained muscle tone maintaines amnesia usually total |
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disadvantages of using ketamine for procedural sedation?
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Nystagmus
hypersecretion vomiting agitation energence delerium myoclonus laryngospasm |
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contraindications to use of ketamine in procedural sedation?
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rise in BP and HR would be harmful
raised intra-occular pressure raised ICP history of hallucinations procedures involving posterior pharynx- risk fo laryngospasm |
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disadvantages of midazolam for procedural sedation?
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provides no analgesia
respiratory and cardiovascular depression |
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advantages of using NO (30-70%) for procedural sedation?
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airway reflexes preserved
minimal cardiovascular depression minimal depression of conscous state rapid onset |
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`Disadvantages of using NO for procedural sedation?
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inadequate analgesua
nausea and vomiting expansion of gas-filled structures therefore contraindicated in abdominal distension, bowel obstruction, decompression thickness, air embolism, intrathoracic injuries, pneumothorax diffusional hypoxia at the end of anesthesia |
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Advantages of propofol for procedural sedation?
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rapid onset and recovery
abscence of hangover effects |
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Disadvantages of propofol for procedural sedation?
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no analgesic activity
transient apnea/ respiratory depression hypotension bradycardia pain at injection site muscle excitation |
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Pharmacologic management of itch
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sedating antihistamines e.g. promethazine- mainly because sedating
non-sedating antihistamines- not effective sedating antidepressant- paroxetine paroxetine opioid- change opioid uraemia: non-pharmacological management HIV: antihistamines BAD, indomethacin + oxpentifyene biliary obstruction: cholestyramine- but poorly tolerated rifampicin or odansetron may be useful |
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Mechanism of action of cholestyramine?
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anion exchange resin: sequester bile acids in the intestine preventing reabsorption and enterohepatic circulation
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What rapid sequence induction agents are more likely to cause hypotension?
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thiopentone and propofol- fentanyl is often preferred in the setting of a head injury to avoid hypotension
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In which situations is rocuronium used instead of suxamethonium for rapid sequence induction?
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hyperkalemia e.g. extensive burns
spinal cord injury conditions where fasciculations may be detrimental e.g. penetrating eye injury cholinesterase deficiency risk of malignant hyperthermia |
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Normal end-tital CO2 level?
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40mmHg
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What level of MET tolerance is considered adequate for most surgeries?
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4 METS
Carrying shopping bags up 2 flights of stairs |
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Who gets an ECG pre-surger?
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>50
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Absolute contraindications to major regional anaesthesia?
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diaorders of coagulation
allergy to local anesthetics sepsis (systemic/local) Inability to communicate Hypovolaemia (with neuraxial block) relative: prior neuro defecit possibility of neuro damage prior to the surgery partial anticoagulation |
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How do you minimise motor block for GA?
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low dose epidural + opioid anaesthesia
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Difference between epidural dose and spinal dose?
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epidural generally 4x spinal
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What ECG leads are used during surgery?
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II and V5 (anterior axillary line in 5th IC space)
Detects > 70% of cardiac ischemia in high risk patients undergoing non-cardiac surgery |
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What are high risk groups for awareness during surgery
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general late 0.1%, high risk 1%
cardiac surgery, caesarian, trauma/massive blood loss, poor LV function, opioid/benzo tolerant If patients in this group have relaxant GA consider BIS monitoring |
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When is it appropriate to use suxamethonium after a major burn?
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In 1st 72 hours but not after as may increase the risk of severe hyperkalemia
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Ventillation strategy after a burn
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low tidal volume +/- permissive hypercapnea
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What is the thyromental distance?
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Distance of the lower mandible in the midline from the mentum to the thyroid notch
Adult patient's neck fully extended <3 finger breadth--> difficult intubation |
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What is a malampatti 4
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only see hard palate and base of tongue
III: base of ucula 2. body and base of uvula and part of tonsil pillars |
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Who gets a CXR before surgery?
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cardiac or pulmonary disease, malignancy, age > 60
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What is ASA 3?
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patient with severe systemic disease that limits activity
stable CAD, COPD, DM, obesity |
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Give some examples of ASA 5?
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ruptured AAA, head trauma with raised ICP
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ASA 2: give some examples
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controlled T2DM
controlled essential HTN obesity smoker |
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How long do you postpone surgery following an MI?
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recommend 4-6 weeks for elective surg
reinfarction 50% mortality <3m: 37% of patients will reinfarct 3-5m: 15% >6m: 5% reduce risk with intensive monitoring and post-op ICU |
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How do you reduce CV morbidity in patients at high risk of CAD while in hospital?
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beta blockers such as atenolol/bisoprolol
initiate with caution due to increased risk of CVA |
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When do you stop entidepressants prior to surgery?
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on morning of
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Is mild-moderate hypertension an independent risk factor for peri-operative cardiovascular morbidity?
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no
target <180/110 |
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Management of asthma pre-surgery?
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at risk of bronchospasm from intubation/delivery of gasseous anaesthetics
inhaled salbutamol immeadiately pre-op deep breathing/incentive spirometry if > 1 pulmonary risk factor |
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Define the MAC of a volatile anaesthetic agent?
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The alveolar concentration of an agent at 1 atmosphere of pressure that will prevent movement in 50% of patients in response to a surfical stimulus e.g. abdominal incision
Often general population will require 1.2-1.3 x MAC MAC roughly additive when adding N2O to a more potent agent |
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How much MAC needed for intubation
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1.3
1.5- block adrenergic response 0.3-0.4- open eyes to commande |
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Mechanism of action of reversing agents for non-depolarising muscle relaxants
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acetylcholinesterase inhibitors: inhibit enzymatic degradation of Ach. Increases Ach at nicotinic and muscarinic receptos- thus displacing non-depolarising muscle relaxant
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At what lecel does the trachea begin and at what level does it bifurcate
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Begins at level of thyroid cartillage- C5
Bifurcates T5 |
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Where does the cuff of an LMA rest
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at the junction of the larynx and the oesophagus- above the vocal cords
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What is the proper distance for endotracheal tube insertion?
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tip should be in midpoint of trachea at least 2cm from carina and prox end should be 2cm from cords
20-23 from corner of mouth for men 19-21 for women |
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Size of endotracheal tube?
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Male- 8-9mm
rem: 7-8mm paeds: (age/4) + 4 |
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SaO2 where cyanosis can be detected?
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just detected: SaO2: 80%
Frank cyanosis: SaO2 67% |
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Oxygen delivery by a hudson mask?
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up to 55%
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Impact of hypothermia during surgery on outcomes
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impairs immune function- so more wound infections
Increases period of hospitallisation- delays healing reduces platelet function/coag- more losses/transfusions triples incidence of VT decreases metabolism of anesthetic agents- prolongs post-op recovery |
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What are causes of intra-op bradycardia
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rule out hypoxemia
arrhythmia baroreceptor reflex (increased BP or increased ICP) vagal (occulocardiac, carotid sinus, airway manip) drugs high spinal/epidural |
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What are usual ongoing fluid losses due to exposure during surgery
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minor: 3ml/kg/hr e.g. lap
intermediate: 6ml/kg/hr e.g. open chole Majot: 9ml/kg/hr e.g. abdo aneurism repair |
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Chrystalloid replacement of blood loss
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3ml for 1ml blood loss
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What are usual ongoing fluid losses due to exposure during surgery
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minor: 3ml/kg/hr e.g. lap
intermediate: 6ml/kg/hr e.g. open chole Majot: 9ml/kg/hr e.g. abdo aneurism repair |
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Chrystalloid replacement of blood loss
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3ml for 1ml blood loss
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By how much does 1U of RBC's increase Hb
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approx 10g/L in a 70kg patient
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Who gets anaphylacticoid transfusion reactions?
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IgA deficient patients recieving IgA containing blood
Future transfusions must be washed/deglycerolised RBC's free of IgA or blood from an IgA deficient donor |
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Time course of TRALI?
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occurs 2-4 hours post transfusion
CXR consistent with acute pulmonary oedema but PA and wedge pressures are not elevated. Usually resolves within 48 hours with O2, mech vent |
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Factors that make post-ope nausea and vom more likely
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young age
female history of PONV non-smoker type of surgery: optho/ENT/abdo/pelvic, plastics Type of anaesthetic: N2O, opiods, volatile agents |
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Major metabolic desturbance post-TURP?
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hyponatremia
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dEFINE NOCICEPTION AND PAIN
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Nociception: detection, transduction and transmission of noxious stimuli
pain: perception of nociception that occurs in the brain |
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Main substance in propagation of pain signals between first and second order neurons (in the dorsal horn)?
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substance P
This synapse is also where most of the descending modulation of pain occurs: involving endorphins, enkephalins, noradrenaline, serotonin and GABA |
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Factors that make post-ope nausea and vom more likely
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young age
female history of PONV non-smoker type of surgery: optho/ENT/abdo/pelvic, plastics Type of anaesthetic: N2O, opiods, volatile agents |
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Major metabolic desturbance post-TURP?
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hyponatremia
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dEFINE NOCICEPTION AND PAIN
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Nociception: detection, transduction and transmission of noxious stimuli
pain: perception of nociception that occurs in the brain |
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Main substance in propagation of pain signals between first and second order neurons (in the dorsal horn)?
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substance P
This synapse is also where most of the descending modulation of pain occurs: involving endorphins, enkephalins, noradrenaline, serotonin and GABA |
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Dose changes to anesthetics in obstetrics
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decreased MAC due to hormonal effects
increased block height due to engoreged epidural veins |
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Most complication of regional anaesthesia in pregnancy
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hypotension
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Order of side effects of systemic toxicity with local anaesthetics
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numbness of tongue, perioral tingling, metallic taste
disorientation, drowsyness tinnitus visual disturbances muscle twitching, tremors unconsciousness convulsions, seizures |
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What is ulsed to lower seizure threshold in LA toxicity?
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diazepam or sodium thiopental
if fails to control seizures consider use of succinylcholine |
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Where is the carina in kids?
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T2 (vs T5 in adults)
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Until when are children obligate nasal breathers?
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5 months
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Where is the narrowest point in the airway of a child?
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at the level of the cricoid
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wHY DO CHILDREN HAVE A GREATER v/q MISMATCH?
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LOWER LUNG COMPLIANCE AS ALVEOLI IMMATURE (MATURE AT AGE 8)
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Paediatric blood vol
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80ml/kg
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When are children able to maintain normal glucose homeostasis when fasted for >8 hours
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age greater than 1 year
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Problems with propofol
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0-30% decreased BP due to vasodilation
caution if allergy to egg/soy |
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What is thiopental
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ultra short acting thiobarbituate/hypnotic
decreased cloride channel opening/facilitate GABA and suppress glutamate avoid in shock/hypo T/porphyria/liver disease/myxedema Accumulates with repeat dosing (not for maint)- T1/2 5-12 hours so post-op sedation lasts hours |
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Special indications for use of ketamine
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major trauma
hypovolemia asthma sympathetomimetic- avoid if can't tolerate hypertension e.g. CHF, increased ICP, aneurism Interracts with TCA's |
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Time course for ketamine actiom
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Dissociate 15s
analgesioa, amnesia, unconc 1 min 10-15 min unconc analgesia 40min amnesia 1-2 hours |
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High doses of fentalyl cause...
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transient muscle rigidity
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What do the volatile anaesthetic agents do to ICP?
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increase it
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What is the least cardiodepressive inhallational anesthetic
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sevoflurane
des causes tachy iso decreases BP and CO, increases HR |
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Duration of action of succinilecjoline
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onset 30-60s
duration 5-10 min NO reversing agents |
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Side effects of succinylchplone
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stimulates muscarinic cholinergic receptos: bradycardia, dysrhythmias, sinus arrest, increased saliva (esp. in kids)
Hyperkalemia Increase ICP/IOP/intragastric press fasciculations, post- op myalgia (minimise by giving small dose of non-depol agent) |
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Muscarinic effects of reversal agents (muscle relaxants)
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bradycardia, salivation, increased bowel peristalsis
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Which patients are prone to hyperkalemis with sicc
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3rd deg burns 24 hrs-6m
traumatic paralysis or neuromuscular diseases e.g. muscular dystrophy/myotonia severe closed head injury UMN lesions |
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Equivalent dosing to 30mg of morphine (oral)
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10mg of IV (3x stronger)
240 of codeine (approx 100x weaker) 100 ug fentanyl IV (300x stronger) 6mg hydromorphone oral/emg parent 20mg oxycodone oral/10IM/SC approx same strength 75-100 pethidine 150mg oral tramadol/100mg IV |
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Equivalent dosing to 30mg of morphine (oral)
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10mg of IV (3x stronger)
240 of codeine (approx 100x weaker) 100 ug fentanyl IV (300x stronger) 6mg hydromorphone oral/emg parent 20mg oxycodone oral/10IM/SC approx same strength 75-100 pethidine 150mg oral tramadol/100mg IV |
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Which pregnant women get DVT prophylaxis antipartum?
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1. Antithrombin deficiency
2. Prior DVT + high risk thrombophilia 3. Multiple prior DVT High risk thrombophilias: persistent antiphospholipid antibodies, compound heterozygosity for prothrombin and factor V leiden mutations, homozygosity for prothrombin and factor V leiden mutations |
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Which women get VTE prophylaxis postpartum?
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Any thrombophilia
1 or more episodes of VTE 4-6 weeks |
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At what INR is surgery considered safe?
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At INR <1.5. Warfarin should be discontinued for at least 4 days pre-op to allow INR to fall. IV heparin or subcut clexane for high risk patients (VTE <12 wks, recurrent VTE,m lupus anticoag, HF with prior stroke, mechanical heart valves).
Post-op re-start clexane 12 hrs after surgery |
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Flora of oesophagus and stomach
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lactobacilli
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What does cefazolin cover?
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strep and methicillin susceptible staph
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What % of untreated patients with a DVT get a PE?
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50%!!!
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