Anaesthetics Flashcards
what is the triad of types of drugs used in anaesthesia
anaesthesia
analgesia
muscle relaxation
name the main opoid antag
naloxone
how do you change the dose when changing from oral morphine to parenteral & why
oral - need twice as much, because only half is absorbed due to 1st pass metabolism by the liver
oxycodone + morphine, what is the diff in strength
oxycodone is 1.5X more potent than morphine
Mx of opoid induced resp depression
call for help
ABC bag and mask ventilate?
IV naloxone
when using morphine, what comorbidities should you be wary in & how could you get around the problem
renal failure
use oxycodone
Why will patient wake up about 10 mins after induction dose of propofol IV when the half-life in the body is about 2 hours?
high cardiac output to the brain at first, then moves to fat stores
local anaesthetic toxicity effects
early Sx & major effect
tinnitis, tingling round lips, agitation
CNS - fits
CV - CV collapse, VF
why do local anaesthetics sometimes include adrenaline
reduce bleeding (vasoconstrictor)
Mx of local anaesthetic toxicity
stop injecting LA call for help ABC benzos for fit intralipid CPR
contraindications to NSAIDs
asthma, renal impairment, platelet
dysfunction, gastric irritation
give the 3 main antiemetic classes and an example of each
5HT3 antagonists - e.g. ondansetron
Antihistamine agents - e.g. cyclizine
Antidopaminergic agents - e.g. metoclopramide
side effect of too much midazolam
apnoea
antag for benzos
flumazenil
60 yr old come for revision knee replacement, seen regularly in chest clinic with COPD, BMI 31.5. How will you assess his respiratory status?
acute - recent RTIs? admissions? ITU? ABx/steroids? home O2?
activity level
peak flow/spirom, sats, resp rate
O/E: hyperexpanded chest, clubbing, wheeze, CO2 retention flap?
60 yr old come for revision knee replacement, seen regularly in chest clinic with COPD, BMI 31.5. How can breathlessness be objectively classified? outline tool used in pre-op assessment
medical research council [MRC] breathlessness scale
- no SOB except strenuous exercise
- SOB when hurrying on level / walking up hill
- walks slower than others, stops after 1 mile/ 15 mins
- stops for breath 100 yrds/ few mins
- too breathless to leave house/ on dressing
how can you globally assess functional status
measurement of exercise tolerance before surgery [METS]
60 yr old come for revision knee replacement, seen regularly in chest clinic with COPD, BMI 31.5. Given this is elective surgery, what measures can be taken to ensure mr jones is in his best physicl condition pre-op?
don't admit any earlier than you need to! [HAP] optimise BMI physical fitness optimise COPD control [chest clinic RV] smoking cessation
60 yr old come for revision knee replacement, seen regularly in chest clinic with COPD, BMI 31.5.
His wife mentions he snores. what’s the relevance +how could you assess furhter?
snoring = mild airway obstruction, may be difficult to intubate
ask about previous anaesthesia/ problems. Examine [mallampati]
60 yr old come for revision knee replacement, seen regularly in chest clinic with COPD, BMI 31.5. Also snores. He wants a GA, what do you think?
spinal more appropraite given COPD, BMI, snoring, and op site
what should be done about a patient’s regular oral steroids when he is going to theatre for a knee replacement?
give extra steroids (IV hydrocort) as body unable to make own to combat stress of op, due to adrenal suppression
60 yr old male goes for knee replacement with combined spinal epidural. How do you manage thromboprophylaxis with an epidural?
LMWH 4 hrs after epidural e.g. enoxaparin
[risk of epidural haematoma]
pulmonary oedema Mx
furosemide GTN morphine [senation of breathlessness] O2 sit patient up
high urea leads to what dangerous complication
encephalopathy
17 yr old presents with LOC.
A: groaning, no stridor
B: spont breathing, RR 20, chest clear
C: HR 105, BP 75/50, CR 4s
what are you concerned about and what action can you take?
^HR, low BP, long CR
fluid bolus 500ml saline over 15 mins
eyes open to pain, groans + withdraws arm when you try to cannulate. what is the GCS?
8
Pt given IM loraz due to agitation. After 5 mins, no eye opening, no movement, no speech. what do you do?
call for help/ resus team
ABCDE
Pt given IM loraz due to agitation. After 5 mins, no eye opening, no movement, no speech.
on ABCDE assessment, the airway is obstructed and sats are 89% despite 15L non-rebreathe. What do you do next?
manage the airway: head tilt, chin lift, jaw thrust. Guedel, LMA. Bag and mask ventilate. Til anaesthetist arrives to intubate
what is a rapid sequence induction
intubation method used in emergency when airway is compromised to avoid aspiration [pt unlikely fasted]
PMH of AF, IHD, HTN. DH: atenolol.
likely ECG changes?
old ischaemia e.g. Q waves
no P waves, irregularly irregular rhythm
bradycardic from atenolol
what are METS?
measure, of exercise tolerance before surgery
why is it important to check U+E pre-surgery
theatre blood loss > AKI
clearing of drugs given
when might you consider doing a pre-op echo
Q waves, previous HF, ankle/pulm oedema
pt on simvastatin, bendrofulmethiazide, ramipril, atenolol, warf, GTN. which drugs need to be stopped pre-surgery?
warf - stop 5 days pre-op
omit morning ramipril [need RAAs working]
what Hb would you transfuse?
7/8
what Ix do you want to do to guide your Mx in what appears clincally to be an acute MI
ECG
trop
CXR
ABG
how do you manage a Pt with acute MI and CXR showing widespread alveolar shadowing, fluid in horizontal fissure, bilat effusions. ?
furosemide IV
pt’s ABG shows met acidosis following an MI. The lactate was high suggesting he’s not perfusing his tissues due to cardiogenic shock. How can you increase blood getting to peripheral tissues?
IV nitrates [peripheral vasodilation]
risks for Diabetics undergoing surgery
^risk of post-op infection
cardiac complications
risk of DKA post-op
gastroparesis - aspiration
how do you manage an insulin dependent diabetic for morning surgery list?
1st on list to reduce fasting usual insulin night before omit morning resume insulin when resume food consider sliding scale
how do you manage a tablet treated diabetic for morning surgery list?
if poor control - treat as insulin-dependent [consider sliding scale]
omit long-acting sulfonyureas only [glibenclamide] - 2/3 days before [hypo risk].
omit morning drugs + take once eating e.g. with lunch
briefly describe how you set up a sliding scale for surgery for a diabetic pt
insulin in saline, infusion that can be run at variable rate according to their BMs
run alongside fluids: saline with glucose + KCl
starvation rules for theatre and 1 exception
clear fluids 2 hrs
food 6 hours
not in CS [ketosis bad for baby]
or emergency surg
what happens if a patient with type 1 DM omits their insulin?
hyperglycaemia > DKA
how do you manage a pt who’s on a sliding scale post-surgery and is now unconsious with a BM of 1.8
ABCDE stop sliding scale/insulin glucogel between teeth 200ml 10% glucose over 15 mins /glucagon IM/IV [200ml OJ if can swallow]
3 criteria for diagnosis of DKA
acidaemia
hyperglyc
ketonaemia/uria
how often do you measure blood gucose and ketones in DKA
hrly
PT Has large coffee ground vomit and is now moribund. you examine him using ABCDE and find his sats to be 89%, what could be causing this?
hypovolaemic shock -> not perfusing tissues with O2
may have aspirated
imediate mx of large upper gi bleed
ABCDE O2 fluid bolus ABG take bloods for group+save/crossmatch, FBC, U+E [transfuse] emergency endoscopy blankets, bear hugger, fluid warmer
what fluids should you not use in fluid resus and why
glucose - water drawn into extravasc space + excreted
how do you treat DIC?
treat underlying
fresh frozen plasma [platelets + clotting factors]
pt with massive upper GI bleed, goes into DIC. What blood products do you give?
FFP
cryoprec
Red cells
how much will one unit of blood raise the Hb by?
10-15
how do you define massove haemorrhage
loss of entire blood vol within 24 hrs
or 50% in 3 hrs
or >150ml/min
complications of massive transfusion
TRALI [Transfusion-related acute lung injury] low platelets low Ca2+ low clotting factors overloading hyperkalaemia hypothermia haemolysis-jaundice transfusion rn-SIRS
what are sepsis, severe sepsis and septic shock?
sepsis = generalised SIR to infection
severe sepsis = organ dysn, low BP
septic shock = inadequate organ perfusion, ^lactate, refractory hypoTN
how do you manage an acutely ill patient who is hypotensive and not responding to multiple fluid challenges
noradrenaline
or Metaraminol
differentials for 28 yr old with sudden onset dyspnoea
asthma LRTI pneumothorax F body valve disease MI cardiomyopathy arrhythmia anaphylaxis panic attack
types of shock
distributive [septic]
cardiogenic
hypovolaemic
neurogenic [spinal - damage to sympathetic chain]
what Ix.s might you specifically do for a patient presenting with an unusual pneumonia
atypical serology [urine, sputum]
HIV test
