ACLS | ACS and Preventing Arrest

Rapid Response System (RRT) Triggers Over half of in-hospital cardiac arrests (IHCAs) stem from respiratory failure or hypovolemic shock[1]. RRS activates based on adult criteria[1]: Airway & Breathing: Airway compromise; respiratory rate <6/min or >30/min[1]. Circulation: Heart rate <40/min or >140/min; SBP <90 mmHg; symptomatic hypertension[1]. Neurological & Renal: Unexpected drop in consciousness; unexplained agitation; seizures; significant urine output drop[1]. Subjective: Clinician concern regarding patient deterioration[1]. II. ACS Classification & Triage The initial 12-lead ECG is central to classifying ACS into two major categories[2]: STEMI: ST elevation in ≥2 contiguous leads (≥2 mm in V2–V3 for men ≥40, ≥2.5 mm for men <40, ≥1.5 mm for women; ≥1 mm in other leads) or new LBBB[4]. Indicates complete coronary occlusion requiring immediate reperfusion[5]. NSTE-ACS: ST depression (≥0.5 mm), dynamic T-wave inversion, transient ST elevation, or normal/nondiagnostic ECG[2][4]. III. Initial Medications & Critical Traps ED assessment within 10 minutes targets ischemia relief and risk triage[3]: Aspirin: Administer 162 to 325 mg (chewed) immediately to inhibit COX-1 and thromboxane A2[4][7]. Suppositories (300 mg) for severe nausea/vomiting[7]. Contraindicated in true allergy or active/recent GI bleed[4][7]. Oxygen: Give (4 L/min) only if SpO2 <90%, dyspneic, hypoxemic, or showing heart failure signs; withhold in normoxic patients[4][7]. Nitroglycerin: Give 1 sublingual dose every 3–5 minutes (max 3 doses)[7][8]. Contraindications: SBP <90 mmHg (or ≥30 mmHg drop below baseline), severe bradycardia (<50/min), tachycardia (>100/min), or RV infarction[4][7]. Morphine: IV for pain unalleviated by nitroglycerin; caution in hypotension or RV infarction[4][7]. Can decrease oral antiplatelet absorption[4]. NSAID Contraindication: NSAIDs (except aspirin) are strictly avoided due to increased risk of mortality, reinfarction, and myocardial rupture[9]. IV. STEMI Reperfusion Timelines Reperfusion within 12 hours of onset limits myocardial necrosis[5][10]: Primary PCI: Preferred strategy[10]. FMC-to-balloon goal ≤90 minutes (≤120 minutes if transferred to PCI facility)[10]. Fibrinolysis: Door-to-needle goal ≤30 minutes[10]. Most effective within 1 hour of symptom onset (reduces mortality by 47%)[5][10]. Not recommended if symptoms >12 hours; contraindicated >24 hours or for ST depression without posterior MI[8]. V. NSTE-ACS & Adjunctive Care High-Risk NSTE-ACS: Early invasive strategy indicated for refractory ischemia, recurrent ST deviation, VT, instability, or heart failure[4][6]. IV Nitroglycerin: For recurrent ischemia, hypertension, or pulmonary edema; titrate maintaining SBP >90 mmHg[8][11]. Heparin: Routine adjunct for PCI and fibrinolysis[8].