Life-threatening emergencies Flashcards
Anaphylaxis:
- Pathophysiology
- Common causes
- Presentation
- Management (normal vs refractory)
PATHOPHYSIOLOGY:
- Mast cells and basophils release mediators (eg: histamine, prostaglandins, thromboxanes, leukotrienes) that produce clinical manifestations
COMMON CAUSES:
- Drugs and vaccines
- IV contrast
- Insect stings
- Foods (eg: nuts, shellfish, wheat)
- Latex
PRESENTATION:
- Onset within minutes-hours
- Prodromal aura of impending death
- Upper airway: swelling of lips, tongue, pharynx, epiglottis
- Lower airway: SOB, wheeze, chest tightness
- Skin: pruritus, erythema, urticaria, angio-oedema
- CVS: hypotension (due to peripheral vasodilation and increased vascular permeability)
- GI: NVD, abdominal cramps
MANAGEMENT:
- Remove triggers
- 100% oxygen
- IM adrenaline 500mcg up to maximum of 2 doses, if still unresponsive, diagnose refractory anaphylaxis and follow algorithm
- Airway adjuncts and emergency intubation
- IV 500ml 0.9% normal saline over 15 minutes for hypotensive shock
- NEB salbutamol 5mg for brochospasm; +/- ipratropium bromide 500mcg
- Antihistamines such as slow IV chlorphenamine 10mg can be given
- H2 blockers such as IV ranitidine 50mg can also be given
- Slow IV hydrocortisone 200mg
- Admit and observe for at least 4-6 hours after symptom resolution
MANAGEMENT OF REFRACTORY ANAPHYLAXIS:
(diagnose this if no improvement after 2 doses of IM adrenaline, 5 minutes apart)
- Continue to give IM adrenaline every 5 minutes until IV access is established
- Take bloods including mast cell tryptase
- Vital sign monitoring
- 100% high-flow oxygen
- Peripheral low-dose IV adrenaline infusion of 1 mg (1 mL of 1 mg/mL [1:1000]) adrenaline in
100 mL of 0.9% sodium chloride
- In both adults and children, start at 0.5–1.0 mL/kg/hour, and titrate according to clinical response
Choking:
- Presentation
- Management
PRESENTATION:
- Sudden-onset airway problem, SOB, unable to speak, clutching neck, often whilst eating and swallowing
- Victims might not be able to speak and may become unconscious
MANAGEMENT:
- If mild airway obstruction, encourage coughing whilst monitoring for deterioration
- If severe airway obstruction, give 5x back blows and 5x abdominal thrusts (ie: Heimlich manoeuvre); if unconscious, start CPR
Cardiac arrest:
- Presentation
- Initial management
- Principles of defibrillation
- Post-resuscitation care
PRESENTATION:
- Clinical suspicion in a person who is unconscious without signs of life
O/E:
- Look, listen and feel for breathing for < 10 seconds (which shows no pulse and no breathing)
INITIAL MANAGEMENT:
(ALS algorithm)
- Shout for help
- Head-tilt, chin-lift, using jaw thrust if neck trauma is suspected; iGel or NPA are good airway adjuncts as alternative to ETT
- Start compressions at 30:2 at a depth of 5-6cm and a rate of 100-120/min
- Apply pads and monitor
- Gain IV access
PRINCIPLES OF DEFIBRILLATION:
- Most survivors have rhythm of VF or VT
- For biphasic defibrillators, use shock energy of 150J
- For monophasic defibrillators, use shock energy of 360J
- Remove sources of danger (eg: oxygen and GTN sprays) if shocking
SHOCKABLE RHYTHM:
- VF or pulseless VT
- Deliver 1 shock then immediately resume CPR for two minutes at 30:2 ratio, during which a reversible cause of the arrest should be searched for
- Deliver 2nd and then 3rd shock; if still refractory after 3rd shock, then give IV adrenaline 1mg and IV amiodarone 300mg, followed by IV adrenaline 1mg every 3-5 minutes (a further dose of IV amiodarone 150mg can be given for refractory VF/VT; lidocaine is an alternative to amiodarone)
- For torsades de pointes and refractory VF with digoxin toxicity or hypomagnesaemia (eg: due to potassium-losing diuretics), give IV magnesium sulfate 2g
NON-SHOCKABLE RHYTHM:
- PEA or asystole
- Immediately resume CPR at 30:2 ratio
- Give IV adrenaline 1mg asap and then thereafter after every 3-5 minutes
- Search for underlying causes (4Hs and 4Ts: hypoxia, hypovolaemia, hyper/hypokalaemia and metabolic disorders, hypothermia; tension pneumothorax, tamponade, toxins and thrombosis (PE/MI))
- If PEA is due to hyperkalaemia, hypocalcaemia or CCB or Mg overdose, then give 10mL of IV 10% calcium chloride
[NB: PEA is a clinical situation of a cardiac arrest with an ECG trace compatible with a cardiac output]
POST-RESUSCITATION CARE:
- Protect airway
- Maintain oxygenation and ventilation under ABG guidance
- If intubated, insert NGT to decompress the stomach
- Order ECG to determine baseline electrical activity and CXR to determine complications of resuscitation (eg: pneumothorax, fractures, position of tubes and central lines)
- Send bloods (FBC for baseline and to exclude anaemia, U&E/Ca2+/Mg2+ to correct electrolyte imbalances
Central venous access:
- Indications
- Contraindications
- Choice of veins
- What is the technique of choice?
INDICATIONS:
- To give emergency drugs
- To measure CVP
- To give IV fluids especially if peripheral veins have collapsed or thrombosed
- Transvenous cardiac pacing
CONTRAINDICATIONS:
- Severe pulmonary disease due to risk of pneumothorax
CHOICE OF VEINS:
- External jugular vein is readily visible and can. be cannulated with standard IV cannulae
- Internal jugular vein and subclavian veins are more commonly used in the ED; but the latter carries higher risk of pneumothorax
- Femoral vein is used for temporary access in severe trauma and burns and in drug users with many thrombosed veins
TECHNIQUE OF CHOICE:
- Seldinger technique (fine needle decreases risk of pneumothorax; insert a metal needle into the vein and thread a flexible guidewire through the needle, which is later removed)
[NB: use USS as guidance]
Sepsis:
- Presentation
- Management
- Neutropenic sepsis
PRESENTATION:
- Fever is the most common presentation of sepsis, but the absence of fever doesn’t exclude it (eg: older and frail adults, chronic alcohol abuser or immunosuppressed people)
- qSOFA score = consider sepsis and commence treatment if patient presents with and one of the following: RR22 or more, SBP 100mmHg or less, and GCS<15
- Prolonged CRT and low spO2 might be indicative
- Skin = mottled or ashen appearance; pallor or cyanosis can indicate sepsis
- Raised lactate can also be indicative
MANAGEMENT:
a) Give 3
- Give fluids of IV crystalloid according to response (eg: 10-20mL/kg although 30-40mL/kg may be required if hypotensive or if lactate raised)
- Give IV broad-spectrum antibiotics (eg: vancomycin, tazocin, ceftriaxone for those without significant PMH, meropenem for those with sepsis of unknown origin)
- Give oxygen with spO2 monitoring
b) Take 3
- Take blood cultures to guide antibiotic therapy
- Take bloods (eg: FBC, CRP, U&Es, LFTs, blood lactate, VBG/ABG)
- Take urine output monitoring (eg: catheterisation) and send of urine samples for dipstix
NEUTROPENIC SEPSIS:
- Be suspicious of this if patient is on systemic chemotherapy or radiotherapy which causes myelosuppression
- It often presents with fever and general “feeling unwell” on a background of chemotherapy for cancer
- Aim to treat within 1 hour of admission
- IV antibiotics should be given empirically without delay for blood results (IV tazocin 4.5g every 8 hours is a common regime)
- Neutrophil count is often < 0.5 x 10^9/L
Shock:
- Presentation
- Classification of shock
- Management
PRESENTATION:
- Hypotension and tachycardia
- Altered consciousness and syncope
- Poor peripheral perfusion (eg: cool peripheries, clammy and sweaty skin, pallor, prolonged CRT)
- Tachypnoea and SOB
- Purpuric rashes
- Oliguria
CLASSIFICATION OF SHOCK:
- Hypovolaemic (eg: bleeding, trauma, burns, UGIB, AAA rupture, ruptured ectopic pregnancies, V+D, pancreatitis)
- Cardiogenic (eg: MI, arrhythmias, valvular dysfunction, cardiac tamponade, massive PE, tension pneumothorax)
- Septic; more common at the extremities of age with PMH of DM, renal/hepatic dysfunction and immunocompromise, recent surgery, IVDU, post-splenectomy, malignancy, indwelling catheters
- Anaphylactic; sudden-onset, rashes, SOB, angio-oedema, ?younger patient
- Neurogenic; history of spinal trauma
- Poisoning
- Addisonian crisis
MANAGEMENT:
- ABCDE
- Oxygenate and initiate spO2 monitoring
- IV access, then take bloods for FBC, CRP, U&Es, LFTs, VBG/ABG, lactate, coagulation screen and blood cultures if appropriate
- Catheterise to monitor urine output
- IV crystalloids (eg: 0.9% normal saline) titrated in small boluses of 20-30mL/kg according to response; give further fluids and aim for Hct > 30%
- Consider passive leg-raise manoeuvre
- Look for underlying causes and treat accordingly
[NB: exercise caution with IV fluid resuscitation in patients with cardiogenic shock or ruptured AAA]
SPECIFIC MANAGEMENT ACCORDING TO CAUSES:
- Intra-abdominal = laparotomy
- MI and PE = thrombolysis
- Tamponade and valvular disease= pericardiocentesis/cardiac surgery
- Poisoning = antidotes
- Sepsis = antibiotics
