Emergency Medicine Decision Tool 2025

⚡

Algorithm 1 of 7

Adult Cardiac Arrest

Shockable & non-shockable pathways — CPR & defibrillation

Cardiac Arrest

Unresponsive · No Breathing / Only Gasping

↓

✓ YES — Definite Pulse

Give 1 breath every 6 seconds
Recheck pulse every 2 minutes

↓

✗ NO — No Pulse

⚡

Activate Team · Begin CPR — 30 compressions : 2 breaths

Continuous compressions until BVM available
O₂ at 15L/min when available

↓

High-Quality CPR

Rate ≥ 100/min · Depth ≥ 5cm · Full recoil after each compression
Interruptions < 10 sec · If intubated: 1 breath every 6 sec

↓

⚡ VF / Pulseless VT

⚡

SHOCK — Biphasic 200J · Monophasic 360J

↓

IV/IO access · Bloods: VBG & RBS
Attach leads; monitor lead II

↓

⚡ Still Shockable

⚡

SHOCK — Biphasic 200J · Monophasic 360J

↓

Adrenaline 1mg IV/IO + 20mL NS flush
Repeat after 2 CPR cycles · Identify & treat reversible causes

↓

⚡ Still Shockable

⚡

SHOCK — Biphasic 200J · Monophasic 360J

↓

1st dose: Amiodarone 300mg IV/IO + 20mL NS flush
2nd dose (after 2 cycles): 150mg IV/IO + 20mL NS flush
Consider advanced airway & capnography

↻ Continue — rhythm check every 2-min CPR cycle

✗ No — PEA/Asystole loop

↻ Adrenaline every 2 CPR cycles · Check for ROSC

✗ No — PEA/Asystole loop

↻ Continue PEA/Asystole — Adrenaline every 2 cycles

✗ Asystole / PEA

IV/IO access · Bloods: VBG & RBS
Attach leads; monitor lead II

↓

Adrenaline 1mg IV/IO + 20mL NS flush
Repeat after 2 CPR cycles · Consider advanced airway & capnography

↓

⚡ Now Shockable

↻ Follow VF/Pulseless VT path above

✗ Still Non-Shockable

↻ Adrenaline every 2 CPR cycles · Check for ROSC

↓

🔍 Reversible Causes — H's & T's

The H'sHypoglycaemia · Hypovolemia · Hypoxia · Hydrogen ion (acidosis) · Hypo/hyperkalaemia · Hypothermia

The T'sTension Pneumothorax · Tamponade (cardiac) · Toxins · Thrombosis (pulmonary) · Thrombosis (coronary)

↓

MedPearls

🐢

Algorithm 2 of 7

Adult Bradycardia

HR < 50/min with pulse — identify instability

Bradycardia

Adult Bradycardia — HR < 50/min with Pulse

↓

Airway: Open, maintain, protect as necessary
Breathing: O₂ if SpO₂ < 94%; assist as needed
Circulation: Cardiac monitor · BP · SpO₂ · ToC · RBS · IV access · FBC, UEC, VBG · 12-lead ECG — don't delay therapy

↓

⚠ UNSTABLE

Notify cardiologist immediately while initiating treatment below.

↓

IV Atropine — First Line

First dose: 0.5mg bolus Repeat every 3–5 min · Max: 3mg

Exclude before use: head injury · hypoxia · hypothermia · heart block · hyperkalaemia · heart transplant

↓

✓ Atropine Effective

Continuous ECG monitoring · repeat vitals · assess for underlying cause.

✗ Ineffective — Second Line

Transcutaneous Pacing

See pacing protocol

First-line if atropine fails

Dopamine Infusion

2–10 µg/kg/min IV

Adrenaline Infusion

2–10 µg/min IV

Glucagon

If β-blocker or CCB overdose

↓

📞

Consult a Cardiologist — urgent

✓ STABLE

Reversible Causes — H's & T'sHypoglycaemia · Hypovolemia · Hypoxia · Hydrogen ion (acidosis) · Hypo/hyperkalaemia · Hypothermia · Tension Pneumothorax · Tamponade · Toxins · Thrombosis

MedPearls

⚡

Algorithm 3 of 7

Adult Tachycardia

HR > 150/min with pulse — stability & QRS width

Tachycardia

Adult Tachycardia — HR > 150/min with Pulse

↓

Airway: Open, maintain, protect as necessary
Breathing: O₂ if SpO₂ < 94%; assist as needed
Circulation: Cardiac monitor · BP · SpO₂ · IV access · FBC, UEC, VBG · 12-lead ECG — don't delay therapy

↓

⚠ UNSTABLE — Immediate Action

🔴

Synchronised Cardioversion

Start 100J — escalate as needed
Consider procedural sedation · Consult Cardiologist

↓

Defibrillation (asynchronous)
Magnesium 2g IV over 10 mins
Overdrive pacing

✓ STABLE — Assess QRS Width

📉 NARROW — SVT (QRS < 0.12s)

NOT if varying R-R intervals / Atrial fibrillation

Valsalva (abdominal pressure / breath holding)
Facial application of ice water
Carotid sinus massage — C/I if bruits, CVS disease, elderly

↓

Adenosine

6mg rapid IV push + 20mL NS flush Then 12mg IV after 1–2 mins if needed

NOT if varying R-R intervals / Atrial fibrillation

↓

β-blockers · Calcium channel blockers · Digoxin
Consult a Cardiologist

📈 WIDE — VT (QRS ≥ 0.12s)

Adenosine

6mg rapid IV push + 20mL NS flush Then 12mg after 1–2 mins

NOT if varying R-R / Polymorphic VT

Amiodarone

150mg IV over 10 mins then 1mg/min × 6 hours

↓

🔴

Synchronised Cardioversion

Start 100J — escalate as needed
Consider procedural sedation · Consult Cardiologist

MedPearls

🔄

Algorithm 4 of 7

Post-Cardiac Arrest Care

ROSC — ventilation, hypotension, temperature management

Post-ROSC

Return of Spontaneous Circulation (ROSC)

↓

Monitor ABCs · Prepared for CPR & defibrillation
Vital signs: BP, PR, RR, SpO₂, ToC, RBS
12-lead ECG immediately
If stable → transfer to ICU attached to defibrillator

↓

Avoid excessive ventilation — start 10–12 breaths/min
Titrate FiO₂ to maintain SpO₂ ≥ 94%
Target PETCO₂ 35–45 mmHg
Consider advanced airway & waveform capnography

↓

Fluid Bolus1–2L Normal Saline or Ringers Lactate IV/IO

If no response — VasopressorAdrenaline: 0.1–0.5 µg/kg/min IV (7–35 µg/min in 70kg adult)
Norepinephrine: 0.1–0.5 µg/kg/min IV (7–35 µg/min in 70kg adult)

↓

Mandatory cardiology consultation if STEMI or ACS suspected.

↓

Keep temp < 36°C for 36 hours
Ice-cold fluids · Ice packs · Intravascular or surface temperature-management

↓

✓ Follows Commands

Continuous ECG · serial vitals · neurological assessment · CCU/ICU care.

✗ Cannot Follow Commands

Maintain temperature management. Neurological prognostication after 72h of normothermia.

↓

🟢

Transfer to ICU/CCU — connected to defibrillator

MedPearls

🫁

Algorithm 5 of 7

ACS Algorithm

12-lead ECG within 10 min of ER arrival

ACS

Chest discomfort suggestive of ischemiaEar, jaw, neck, shoulder, arm, back, epigastric pain; dyspnoea; nausea/vomiting; diaphoresis; fatigue

↓

⏱

12-lead ECG within 10 minutes of ER arrival

V4R if ST↑ V1 + ST↓ V2 → Right-sided STEMI
V7–V9 if ST↓ ≥1mm + upright T in ≥2 anterior leads → Posterior STEMI
ST↑ aVR ≥1mm + widespread ST↓ → Interventional Cardiology immediately (L main/LAD)
Sinus tach + T inversion III,V1,V3 or S1Q3T3 → Pulmonary Embolism Algorithm

↓

Prepared for CPR & defibrillation
Vital signs: BP, PR, RR, SpO₂, ToC, RBS
O₂ if SpO₂ < 90% or dyspnoeic — maintain SpO₂ ≥ 90%
IV access: left forearm or antecubital vein
Bloods: UEC, Coagulation screen, hsTroponin T (if ≥4h from symptom onset)
Brief targeted history & exam — document symptom onset time

↓

Aspirin

300mg to chew

If not given by EMS · not allergic · no active UGI/retinal bleed · not haemophiliac · no severe untreated BP

Nitroglycerin SL Spray

0.4mg SL every 5 min — MAX 3 doses

DO NOT give if: SBP <90mmHg or 30mmHg below baseline · HR >100 or <50 bpm · RV infarction · Sildenafil/vardenafil ×24h or tadalafil ×48h

Fentanyl

50µg IV if pain NOT relieved by 3 nitro doses Repeat once after 5 min if still in pain

Persistent pain → consult Cardiologist · consider IVI nitroglycerin

↓

Rule out: pulmonary embolus · cardiac tamponade · aortic dissection · tension pneumothorax

↓

🔴 STEMI

🟡 High-Risk UA/NSTEMI

🔵 Intermediate/Low Risk UA

↓

Sgarbossa Criteria for LBBB — either criterion sufficient

1. Concordant ST elevation ≥ 1mm in at least 1 lead
2. Concordant ST depression ≥ 1mm in V1–3

MedPearls

🚨

Algorithm 6 of 7

STEMI Algorithm

PCI within 90 min · Fibrinolysis within 30 min if PCI unavailable

STEMI

ST Elevation or LBBB meeting Sgarbossa criteria — STEMI

↓

Criteria	Pts	Score	30-Day Mortality (%)
Age ≥ 75	3	0	0.8
Age 65–74	2	1	1.6
DM / HTN / Angina	1	2	2.2
SBP < 100 mmHg	3	3	4.4
HR > 100 bpm	2	4	7.3
Killip class 2–4	2	5	12
Weight < 67 kg	1	6	16
—	—	7	23
Anterior STE or LBBB	1	8	27
Time to Rx > 4 hrs	1	>8	36

Score 0–14 · Entry: CP >30 min, ST↑, onset <6h, fibrinolytic-eligible

↓

✗ > 12 hours

📞

Consult an Interventional Cardiologist

✓ ≤ 12 hours — Reperfusion

⭐ PRIMARY PCI — Preferred

⏱

Cathlab within 90 minutes of ER arrival

↓

Pre-PCI Medications

Clopidogrel 600mg OR Prasugrel 60mg OR Ticagrelor 180mg Atorvastatin 80mg

Obtain informed consent

💊 FIBRINOLYSIS

Pre-Fibrinolysis Drugs

1. Clopidogrel 600mg 2. Enoxaparin: <75y: 30mg IV bolus then 1mg/kg SC (max 100mg ×2) ≥75y: no bolus · 0.75mg/kg SC (max 75mg ×2) CrCl <30: 1mg/kg SC (any age) 3. Atorvastatin 80mg

↓

Absolute Contraindications

Any prior intracranial haemorrhage
Structural cerebral vascular lesion (e.g. AVM)
Malignant intracranial neoplasm
Ischaemic stroke within 3 months (EXCEPT acute within 3h)
Suspected aortic dissection
Active bleeding or bleeding diathesis (excluding menses)
Significant closed head/facial trauma within 3 months

Relative Contraindications

Chronic severe poorly controlled hypertension
SBP >180 or DBP >110 mmHg on presentation
Prior ischaemic stroke >3 months / dementia / intracranial pathology
CPR >10 min or major surgery <3 weeks
Internal bleeding within 2–4 weeks
Non-compressible vascular punctures
Streptokinase: prior exposure >5 days or prior allergic reaction
Pregnancy · Active peptic ulcer
Anticoagulants: higher INR = higher bleed risk

↓

Obtain informed consent · Connect to defibrillator (ECG, SpO₂, BP) · Repeat baseline vitals

↓

TENECTEPLASE

<60kg → 30mg (6mL) 60–69kg → 35mg (7mL) 70–79kg → 40mg (8mL) 80–89kg → 45mg (9mL) ≥90kg → 50mg (10mL)

IV bolus over 5 sec · Reconstitute: 50mg vial in 10mL sterile water (5mg/mL)

STREPTOKINASE

1.5 million U in 50mL D5W IV over 60 min

Set up 2nd IV line · Run NS/RL TKVO in other line · Allergic reactions may force early termination

↓

Continue monitoring 30 min post-infusion · Transfer to CCU/ICU connected to defibrillator

MedPearls

⚠️

Algorithm 7 of 7

UA / NSTEMI Algorithm

Risk stratification — hsTroponin T and TIMI score

UA/NSTEMI

High-Risk UA/NSTEMI or Intermediate/Low Risk UAST depression >0.5mm or T-inversion ≥2mm — OR — Normal/non-diagnostic changes

↓

Risk Factors — each = 1 point (0–7 total)

Age > 65 years
≥ 3 CAD risk factors (family Hx, HTN, hypercholesterolaemia, DM, current tobacco)
Known coronary stenosis ≥ 50%
ST-segment deviation
≥ 2 anginal events in previous 24 hours
Aspirin use in previous 7 days
Elevated serum cardiac markers (hsTrop T)

TIMI Score	30-Day Risk: Death/MI/Revasc (%)
0	2.1
1	5.0
2	10.1
3	19.5
4	22.1
5	39.2
6	45.0
7	100.0

↓

🔴 HIGH RISK

📞

Consult a Cardiologist / Physician — urgent

↓

Serial ECGs to detect dynamic changes or evolution to STEMI.

↓

→ STEMI

✗ No STEMI — NSTEMI Management

Antiplatelet therapy · anticoagulation · early invasive vs conservative strategy per cardiology guidance.

✗ hsTroponin T < 14ng/L

⚠ Elevated Risk

📞

Consult Cardiologist / Physician

↓

Serial ECG monitoring for dynamic changes.

✓ Low Risk — Assess for Discharge

Discharge Criteria — must meet ALL

Two ECGs: Normal · No ST depression · No dynamic changes
hsTroponin T < 14ng/L at ≥ 4h from symptom onset OR 3h from ER admission
If Troponin done <4h from symptom onset → repeat at 3h from ER admission

↓

Arrange outpatient cardiology review as clinically indicated. Patient education and safety netting.

MedPearls