Emergencies and substance abuse Flashcards
mechanism of action of adrenaline
alpha-receptor agonist (reverses peripheral vasodilation and oedema)
also has beta-receptor activity (dilates bronchial airways, increases force of myocardial contraction and suppresses histamine and leukotriene release)
dosage of adrenaline to use for anaphylaxis at different ages
- adult >12 = 500mcg
- child 6-12 = 300mcg
- child <6 years = 150mcg
first choice vasopressor in septic shock
noradrenaline
dobutamine can be added if myocardial dysfunction
leading cause of death in acute MI
cariogenic shock
stages I-IV of haemorrhagic shock
I = <15% blood loss II = 15-30% III = 30-40% IV = >40%
examples of non-haemorrhagic hypovolaemic shock
- dehydration, D&V, burns, polyuria
- 3rd space loss - pancreatitis, ascites
why not to push BP >100 if in haemorrhagic shock
might dislodge clot trying to form
when to consider major haemorrhage protocol and what does it entail
- actively bleeding, HR >110, BP <90
- 4 units blood, 4 units FFP every 20 mins
causes of T2RF
- COPD
- near fatal asthma
- drug overdose/poisoning
- myasthenia gravis
- polyneuropathy
- muscle disorders
usual cause of cardiogenic pulmonary oedema
complication of MI/IHD
usual cause of non-cardiogenic pulmonary oedema
IV fluid overload
could also be caused by decreased plasma oncotic pressure e.g. hypoalbuminaemia
ABG result in pulmonary oedema
acidotic - not perfusing tissues
hypoxic and hypercapnia - impaired gas exchange
lactate likely elevated - tissues hypo perfused
dose of furosemide to give in pulmonary oedema/acute heart failure
20-40mg if diuretic naive
otherwise 40mg
antiemetic to give in pulmonary oedema
ondansetron 4-8mg
signs of obstructive shock
fluid overload:
- pulmonary oedema
- cardiomegaly
- raised JVP
causes of obstructive shock
- PE
- tension pneumothorax
- cardiac tamponade
basically blocking outflow of blood from heart
brain complication of paracetamol overdose
hepatic encephalopathy
LFT results in paracetamol overdose indicating hepatotoxicity
ALT >1000
blood glucose level in paracetamol overdose
hypoglycaemic
amount of paracetamol ingested suggesting severe liver damage
> 150mg/kg
more than 24 tablets (12g) is potentially fatal
what drugs increase paracetamol toxicity
p450 INDUCERS: P CARBS
P - phenytoin C - carbamazepine A - alcohol (chronic) R - rifampicin B - barbiturates S- sulfonylureas
when can pabrinex (NAC) be stopped after paracetamol overdose
once INR <1.3 and ALT <2x upper limit of normal/hasn’t doubled
when to consider liver transplant for paracetamol overdose
if pH <7.3 24 hours after ingestion OR
- PTT >100 seconds AND
- creatinine >300 ANDF
- grade III or IV encephalopathy
how much naloxone to give in opiate overdose
0.4-2mg
may require infusion/multiple doses (IV/IM)
ECG findings in TCA overdose
- sinus tachycardia
- widening PR or QRS complexes - QRS >100ms associated with increased risk of seizures
- QTc heart block
- ventricular dysrhythmias
drugs to give in TCA overdose
- IV bicarbonate
- IV lipid emulsion (binds free drug and reduces toxicity)
doses of salicylates likely to cause toxicity (e.g. aspirin)
> 250mg/kg - moderate
> 500mg/kg - severe/fatal
how to take plasma salicylate concentration
- taken 2 hours (symptomatic) or 4 hours (asymptomatic) after ingestion
- repeat after a further 2 hours
- intoxication usually associated with concentrations >350mg/L
- check potassium every 3 hours
when is hospital admission not required for aspirin overdose
ingested <125mg/kg and no symptoms
when to consider activated charcoal/gastric lavage for aspirin overdose
- charcoal if >125mg/kg less than 1 hour ago
- gastric lavage if >500mg/kg less than 1 hour ago
when to do haemodialysis in aspirin overdose
- serum concentration >700mg/L
- metabolic acidosis resistant to treatment
- acute renal failure
- pulmonary oedema
- seizures
- coma
antidote to iron overdose
desferrioxamine mesylate IV
mechanism of action of ketamine
NMDA antagonist
mechanism of action of cocaine
monoamine reuptake inhibitor
potentiates dopaminergic, serotinergic and noradrenalinergic transmission
what can be used for heroin detox
- symptom relief = lofexidine (alpha agonist)
- loperamide
- metoclopramide
- ibuprofen
- methadone or buprenorphine or dihydrocodeine
mechanism of action of benzodiazepines and GHB
GABA agonist
how long to give chlordiazepoxide for alcohol withdrawal
over 5-7 days with reducing dose
management of delirium tremens
parenteral thiamine (Pabrinex):
- no WK syndrome = 250mg/day for 3-5 days
- WK syndorme = 500mg/day for 3-5 days
prophylactic carbamazepine (if previous hx of seizures)
chlordiazepoxide
what counts as binge drinking
twice the recommended daily unit limit in one session - 6 units
