crit care Flashcards
Causes of obstructive lung disease
Asthma
bronchiectasis COPD
bronchiolitis obliterans
Causes of restrictive lung disease
pulmonary fibrosis
kyphsclerosis
ARDS
neuromuscular causes
Spirometry findings in obstructive LD:
FEV1
FVC
FEV1/FVC
Reduction in FEV1>FVC
hence FEV1:FVC reduced <70%
Spirometry findings in RESTRICTIVE LD:
FEV1
FVC
FEV1/FVC
Reduction in FEV1<FVC
hence FEV1:FVC normal/ raised >70%
Anaesthetic agent that has both anaesthetic and analgesic properties but causes dissociative anaesthetic effect (hallucinations/ nightmares)
Ketamine
Anaesthetic agent causing the most and least myocardial depression
most= sodium thiopentone (squeezy)
least= Etomidate
Anaesthetic agent causing adrenal suppression
Etomidate
Anaesthetic agent that has anti-emetic properties
Propofol
Anaesthetic agent which is used in RSI
Sodium thiopentone (speedy)
Why are sodium thiopentone and etomidate unsuitable for maintaining sedation
ST= metabolites build up quickly
E= causes adrenal suppression even with brief use
Side effect of using Etomidate
PONV
Causes of neuropathic pain
damage to nervous system:
diabetic neuropathy
trigeminal neuralgia
post-herpetic neuralgia
prolapsed IV disc
First and second line mx of neuropathic pain
1= amitriptyline/ pregabalin
2= add amitriptyline/ pregabalin
3= refer to pain specialist, neurectomy
Mx of diabetic neuropathy
Duloxetine
Mx of trigeminal neuralgia
Carbamazepine
How much calories should be given to a non-severely ill patient with BMI<25
25-35kcal/kg/day
What is the daily requirement of protein
0.8-1.5g/kg/day
How much calories should be given to a severely ill patient
50% of 25-35kcal/kg/day in the first 24-48hrs
How many calories should be given to a patient at risk of refeeding syndrome
10kcal/kg/day
What other supplements should be given to those at risk of refeeding syndrome
Pre-feeding and during feeding:
Thiamine (200-300mg)
Vitamin B complex strong 1tab TDS
Potassium (2-4)
Magnesium (0.2-0.4)
Phosphate (0.3-0.6)
causes of refeeding syndrome
reduced intake:
eating disorders
chemo
vomiting
post-op
fasting
prolonged NBM
reduced absorption
chemo
IBD
short bowel syndrome
pancreatitis
cystic fibrosis
describe the pathophysiology of refeeding syndrome
prolonged reduced nutrients= reduced levels of body phosphate, K, Mg (serum levels normal)
Start eating= increase in glucose + insulin= rapid shift of phosphate, Mg, K into cells for use= decrease in serum phos, Mg, K levels= seizures, arrthymias
What are the types of muscles relaxants
(all end in -ium)
Suxamethonium
Atracurium
Vecuronium
Pancuronium
Which muscle relaxant causes generalised muscle contractions and why
Suxamethonium
Because it is a depolarizing Neuromuscular blocker hence prior to paralysis the depolarization of the NM membrane causes muscle fasciculations
How is sux broken down in the body
By cholinesterase and acetylcholinesterase
What does sux act on to produce muscle paralysis
Acetylcholine receptors at the NM junction
What are the adverse effects of sux
-malignant hyperthermia
-increased intraocular pressure
-prolonged paralysis (in those with reduced pseudocholinesterase levels )
-hyperkalaemia (not good in burns/ necrosis pt= hyperk= cardiac arrest)
Which muscles relaxant is the quickest acting and shortest duration
suxamethonium
How quickly do atracurium, vecuronium and pancuronium act
atra + vecronium= 30-40mins
pancuronium= 2-3mins
Which muscle relaxant is broken down in the liver/ kidneys
pancuronium + vecuronium
How is atracurium broken down
by hydrolysis in tissues and causes histamine release
Adverse effects of atracurium
Histamine release= flushing, tachycardia, hypotension
Reversal agent for non-depolarizing muscle relaxants
non-depolarizing= neostigmine
Which muscle relaxant is the only depolarising neuromuscular blocker
suxamethonium
Sx of malignant hyperthermia
hyperpyrexia
muscle rigidity
Pathophysiology of malignant hyperthermia
genetic defect:
administration of anaesthetic/ anti-psychotic/ anti-emetic= excessive release of Ca from sarcoplasmic reticulum in skeletal muscles= muscle rigidity + pyrexia
Mx of malignant hyperthermia
Dantrolene-inhibits ca release from sarcoplasmic reticulum
Drugs that can cause malignant hyperthermia
anaesthetic/ muscle relaxants/ anti-psychotic/ anti-emetic
haloperidol
prochloperazine
metaclopramide
risperidone
What is the gene + chromosome involved in malignant hyperthermia
Chromosome 19, ryanodine receptor (controls Ca release from SR)
How can malignant hyperthermia be diagnosed
raised CK
Contracture tests on muscle biopsy exposed to halothane/ caffeine
Side effect of neostigmine and how can this SE be countered
SE= Bradycardia
Given with atropine
WHat is cryoppt made of?
Factor 8
Factor 13
vWB factor
fibrinogen
Pathophysiological changes seen in ARDS
b/l pulmonary infiltrates
(non-cardiogenic)
hypoxaemia (due to reduced diffusion)
Causes of ARDS
sepsis
pancreatitis
directly injury/ trauma
fat embolism (long bone/ multiple #)
aspiration
Features of ARDS
hypoxia
tachypnoea
tachycardia
Mx of ARDS
treat underlying problem:
sepsis= IV ABx
negative fluid balances (diuretics)
recruitment manoeuvres (prone ventilation/ positive and expiratory ventilation)
mechanical ventilation with low tidal volumes (prevent alveolar damage)
Why is midazolam preferred as a procedural sedative
amnaesia effect
What class of drug is flumazenil
selective GABA receptor antagonist
How is midazolam excreted
in the liver (via cytochrome P450 path)
What does TPN consist of
lipids
glucose
electrolytes
(NO FIBRE)
complications of TPN
fatty liver + deranged LFT
thrombophlebitis (if admin through small vessels)
sepsis
refeeding syndrome
What are the 2 types of neuromuscular blocking drugs and what is their MOA
deplorazing and non-depolarizing neuromuscular agents
block Ach from acting on receptor at the NM junction
What is the pulmonary artery occlusion pressure
Measures the pressure of the LEFT atrium
Target values for:
urine output
MAP
CVP
URINE O/P: 0.5ml/kg/hr
MAP >65
CVP 8-12
What are the different vassopressors available
Adrenaline
noradrenaliine
dopamine
dobutamine
metaraminol
milrinone
Which vasopressors are alpha agonists
noradrenaline, metaraminol
Which vasopressors are alpha and beta agonists
adrenaline
Which vasopressors are beta 1 agonists
dopamine
Which vasopressors are beta 1 & 2 agonists
dobutamine
Which vasopressors cause increased SVR
adrenaline, noradrenaline
(those that DO NOT act on beta receptors)
Which vasopressors cause increased cardiac output
all that act on beta receptors
adrenaline
dopamine
dobutamine
What effect does dobutamine have on cardiac output and SVR
b1 +b2 agonist:
increases cardiac contractility + rate+ BP =increased cardiac output
vasodilation= reduced SVR
What is the MOA of Milrinone and what are its effects
phosphodiesterease inhibitor =
increased muscle contractility + vasodilator
(same as dobutamine)
What are the effects of alpha agonists on the heart and SVR
no effect on cardiac output
increase SVR
What variables can the swan ganz catheter be used to measure
oxygen delivery
pulmoary artery resistance
systemic vascular resistance
stroke volume
Where would a swan ganz catheter be sited
pulmonary artery
Adverse effects of Dextrans for fluid resuscitation
Anaphylaxis
Acute renal failure
Indication for using an uncuffed ET tube
in children
to prevent damage to larynx
Which ionotrope can be given through a peripheral vein
metaraminol
How long does the effect of clopidogrel last
120 days
(need to stop 5-7 days pre-op)
MOA of clopidogrel
anti platelet= acts on ADP to inhibit plt aggregation
ECG features of hyperkalaemia
Tall T waves
broad QRS
flattened P waves
VF
When would you test for brain stem death
-Unexplained deep coma
-reversible causes have been excluded
-normal electrolytes
-not under sedation
What is involved in testing for brain stem death
-fixed pupils, not reactive to light
-no corneal reflex
-no rxn to supra-orbital pressure
-no oculo-vestibular reflex*
-no cough reflex to bronchial stimulation
-no gag reflex to pharyngeal stimulation
-no visible respiratory effort when taken off ventilator for atleast 5min (to allow for adequate arterial partial pressure of CO2 -6-6.5kPa)
*no eye movements to the slow injection of atleast 50ml of ice-cold water into each ear in turn
Who can test for brain stem death
need 2 doctors to carrying out test on 2 separate occaisions
-Both need to be >5yrs post grad
-1 needs to be a cons
-neither can be part of the transplant team
Complications caused by massive transfusion
hypothermia (blood stored in the cold)
hypocalcaemia (FFP + plt have citrate antioaoagulant= causes chelation of Ca)
hyperkalaemia (older blood= higher K)
transfusion associated lung injury
coagulopathy (causes dilution and reduced plt, fibrinogen, clotting factors)
Describe the pathophysiology of transfusion associated lung injury
transfused plasma contains antibodies to leukocytes
leukocytes aggregate and breakdown in the lungs causing damage to alveoli
Inflammatory infiltrates in b/l pleura
Which anaesthetic agent is associated with hepatotoxicity
halothane
Patient presents with an acute dystonic rxn (due to anti-psychotic meds + metoclopramide given), what meds can reverse this
procyclidine
benzhexol
What are the features seen in an acute dystonic rxn
acute torticolis
oculogyric crisis
oromandibular dystonia
What is included in the enhanced recovery programmes
Admission on the day of surgery
Reduced starvation times (if under GA= carbohydrate loading drink 2 hrs pre-op)
Not for diabetics with complex insulin regimens
Intra-op DO NOT give IV fluids= can cause interstitial oedema and increase complication rates
Post-op:
early ambulation
eat orally within 24hrs
reduced IV fluids= ileus
take out IV/ drains/ catheters
encourage getting dressed and walking around ward
