Prescribing in Medical Emergencies

what is a medical emergency?

a serious and unexpected situation involving illness or injury and requiring immediate action

for drug related anaphylaxis, do you supply a patient an epipen?

no- make patient aware of allergy, put on records, and advise patient to avoid this medication

what are the 2 types of epipens? how many epipens should you supply?

• epipen and epipen junior

• supply 2 epipens

what are the steps to use an epipen?

• remove pen from protective case

• sit patient down → if they are dizzy, lay them down

• remove blue cap (safety cap to ensure needle doesn’t come out when not in use)

• gently push auto-injector into thigh (can be administered over clothes)

• once needle has hit, hold it there for 3 SECONDS then remove it

• if person is unconscious, lay them in recovery position

• once used, a needle cover will automatically appear over needle to prevent injury

• used epipen should be given to emergency services so they know what’s been administered and how to dispose of it

what should you check regularly about your epipen?

ensure they are not expired

what are high risk signs for sepsis?

• resp. rate that is 25 breaths/min or more

• heart rate over 130 bpm

• AKI

• not passed urine in previous 18 hrs

• new confusion

• mottled appearance or non-blanching rash

what are moderate risk signs for sepsis?

• respiratory rate21-24 breaths/min

• HR 90-130 bpm

• trauma/surgery/procedure in last 6 weeks

• immunocompromised

• not passed urine in previous 12-18 hrs

what is the CIWA chart?

used to score alcohol withdrawal, looks at:

• resp. rate

• nausea/vomiting

• tremor

• sweats

• anxiety

• agitation

• tactile disturbances

• auditory disturbances

• visual disturbances

• headache

• orientation

what do you monitor during a paracetamol overdose?

• serum paracetamol conc.

• salicylate levels

• ECG and cardiac monitor

• LFTs

• prothrombin time and INR

• urea and creatine

• electrolytes

what is the GCS score?

confusion score → 15 = fully alert

what is a single acute overdose of paracetamol?

ingestion of all paracetamol within 1 hr

how do you treat a single acute paracetamol overdose when it has been less than 8hrs post ingestion?

• if more than 150 mg/kg body weight paracetamol ingested in the last hour → treat with activated charcoal = 50 g in adults, 1 g/kg in children

• in children less than 6 yrs old → if paracetamol ingestion is less than 150 mg/kg and asymptomatic then no further investigations or treatment necessary

• paracetamol ingestion greater than 75 mg/kg body weight or symptomatic → take bloods at 4 hrs post ingestion for paracetamol conc, INR, LFTs, renal function, venous blood gas (VBG)

• paracetamol concentration above or within 10% of treatment line and/or ALT abnormal → start NAC

how do you treat a single acute paracetamol overdose when it has been 8-24hrs post ingestion?

• in children less than 6 yrs old → if paracetamol ingestion is less than 150 mg/kg and asymptomatic then no further investigations or treatment necessary

• take bloods at presentation → if paracetamol ingestion is greater than 150mg/kg start NAC otherwise wait for blood results

• paracetamol concentration above or within 10% of treatment line and/or ALT abnormal → start NAC if not already

• if below treatment line and ALT normal then stop NAC

how do you treat a single acute paracetamol overdose when it has been more than 24hrs post ingestion?

• in children less than 6 yrs old → if paracetamol ingestion is less than 150 mg/kg and asymptomatic then no further investigations or treatment necessary

• take bloods at presentation

• start NAC if patient is symptomatic e.g. vomiting, abdominal pain

• start NAC if bloods show ALT above upper limit of normal, INR above 1.3 or paracetamol detected

what is an intentional staggered overdose?

non therapeutic ingestion of excessive paracetamol over a period of more than 1 hr

how do you treat an intentional staggered overdose OR if the time of overdose is unknown?

start NAC without delay

• take bloods at least 4 hrs after last known ingestion

• NAC can be stopped if all the following conditions are met:

  • paracetamol level below 10 mg/l

  • ALT normal

  • INR below 1.3

  • patient has no symptoms to suggest liver damage

what is a therapeutic excess overdose?

ingestion of excessive paracetamol with intent to treat pain/fever without self-harm intent

how do you treat a therapeutic excess overdose?

maximum dose of paracetamol ingested greater than 75/mg within 24 hr period

• take bloods at least 4 hrs after last known ingestion

• start NAC is symptomatic or signs of liver injury

• start NAC is paracetamol conc is more than 10mg/l or ALT abnormal or INR greater than 1.3

what is the threshold for treatment of individuals with an single acute overdose at the 4 hr period?

100 mg/l

what is the treatment regimen for NAC?

same regimen irrespective of the type of overdose:

• 100 mg/kg over 2 hrs followed by 200 mg/kg over 10 hrs

• dosing is based on actual body weight → max of 110 kg (patients over 110kg should be dosed based on weight of 110 kg)

describe the MOA of NAC in treating a paracetamol OD

• when paracetamol is taken in large quantities, NAPQI metabolite accumulates

• NAPQI is usually conjugated by glutathione to form cysteine and mercapturic acid conjugates but in overdose, glutathione reserves are not enough to deactivate the toxic NAPQI

• NAPQI reacts with hepatic enzymes causing liver damage

• NAC acts by replenishing glutathione reserves in liver

what is the max oral and IV paracetamol dose?

• oral: 1g QDS :. 4g/24 hrs

• IV: 1g QDS BUT a maximum dose of 15mg/kg up to 1 kg → important for lighter patients

• :. for a patient who is 50kg, maximum IV dose if 750 mg QDS

what reference source is used for overdoses?

toxbase

what are symptoms of amitriptyline overdose?

• tachycardia

• hot dry skin

• dry mouth and tongue

what are symptoms of anaphylaxis?

• GI → vomiting, diarrhoea, nausea, abdominal pain

• oral → swelling of lips, tongue and palate

• respiratory → SOB, airway swelling, wheeze

• cutaneous → rash, flushing

• CV → hypotension, tachycardia, fainting

• CNS → confusion caused by hypoxia

what is the treatment for anaphylaxis? give ages and their doses

IM adrenaline

• over 12 yrs → 500 mcg (0.5 ml)

• 6-12 yrs → 300 mcg (0.3 ml)

• 6 months - 6 hrs → 150 mcg (0.15 ml)

• less than 6 months → 100-150 mcg (0.1-0.15 ml)

what do you do if there is no response after administrating IM adrenaline for anaphylaxis?

repeat IM adrenaline after 5 mins

what is the ABCDE assessment for anaphylaxis?

• airway

• breathing

• circulation

• disability

• exposure

why do we use IM adrenaline over IV?

greater margin of safety

what receptors does IM adrenaline act on?

• alpha1 → increase in vasoconstriction in skin, increase in BP, decrease mucosal oedema

• beta1 → increase cardiac contraction force, increase HR

• beta2 → increase bronchodilation and vasodilation in skeletal muscle, decrease mediator response

what are other treatments used during anaphylaxis?

• high flow oxygen

• IV fluid challenge → increases blood volume :. increases blood pressure to increase organ perfusion

• IV chlorphenamine (= antihistamine) → blocks histamine release from mast cells :. reduces bronchoconstriction

• IV hydrocortisone → anti inflammatory effects

what are the common substances that cause anaphylaxis and the mechanisms responsible for the reaction? (6)

• stings, food, antibiotics → IgE mediated reactions

• whole blood, immunoglobulins → complement mediated reaction

• radio contrast media, LMWH → non-immunological mast cells activators

• opioids → mast cell activators

• aspirin, NSAIDs → modulators of arachidonic acid metabolism

• sodium and potassium sulphites → sulphiting agents