What are the priorities and initial management steps for various emergency cases, including cardiac arrest, shock, hypoxia, sepsis, trauma, and behavioral and mental health concerns?

Emergency Case Management: Priorities and Pathophysiology for Paramedic OSCE/Viva

General Approach to All Emergency Cases

Your primary goal in every case is to identify and treat immediately life-threatening conditions using a systematic approach that prioritizes airway, breathing, circulation, and disability assessment, while simultaneously considering reversible causes of deterioration. 1

Universal Initial Actions

• Start with high-quality CPR immediately if pulseless: 30 compressions to 2 breaths, compression depth at least 5 cm, rate 100-120/minute, minimize interruptions 1
• Assess using NEWS2 scoring for all patients aged 16+ with suspected infection or deterioration to stratify risk (score ≥7 indicates high risk requiring urgent intervention) 2
• Secure airway and provide oxygen targeting SpO2 92-98% in most cases, avoiding hyperoxia which increases mortality in cardiac arrest, stroke, traumatic brain injury, and sepsis 3

---

Cardiac Arrest Management

Pathophysiology

Cardiac arrest represents cessation of effective cardiac mechanical activity, resulting in immediate cessation of cerebral and systemic perfusion. Survival depends on rapid recognition and high-quality CPR. 1

Priorities

• Immediate CPR with C-A-B sequence for most arrests: compressions first, then airway, then breathing 1
• Exception: Use A-B-C sequence for drowning victims due to hypoxic nature of arrest - these patients need ventilation first 2
• Apply AED/defibrillator immediately when available, deliver one shock if indicated, resume CPR for 2 minutes before rhythm reassessment 1
• Establish IV/IO access and administer epinephrine 1 mg every 3-5 minutes for all rhythms 1
• For refractory VF/pulseless VT: give amiodarone or lidocaine after failed defibrillation attempts 1
• Secure advanced airway (endotracheal tube or supraglottic device) with waveform capnography confirmation, then provide 10 breaths/minute with continuous compressions 1

Special Considerations

Pregnant patients (≥20 weeks):

• Perform manual left lateral uterine displacement during CPR to relieve aortocaval compression 2
• Prepare for perimortem cesarean delivery (PMCD) immediately if no ROSC - summon resources as soon as arrest recognized 2
• Perform PMCD within 5 minutes of arrest if no ROSC achieved, as shorter time to delivery improves both maternal and fetal outcomes 2
• Prioritize airway management early as pregnant patients desaturate faster due to increased oxygen consumption and decreased functional residual capacity 2

Drowning victims:

• Use A-B-C sequence: give 2 rescue breaths first before compressions due to hypoxic arrest mechanism 2
• Do NOT perform abdominal thrusts or Heimlich maneuver - water is not a foreign body obstruction and these maneuvers delay CPR 2
• Expect vomiting (occurs in 66-86% of cases) - turn patient to side, clear airway, resume CPR 2

Lightning strike/electrical injury:

• Prioritize victims in cardiac arrest when multiple casualties (reverse triage) - those without arrest have excellent prognosis 2
• Primary mechanism is asystole from massive depolarization, but intrinsic rhythm may return spontaneously 2
• Secondary arrest from respiratory failure is common - maintain ventilation even after ROSC to prevent hypoxic re-arrest 2

Hypothermic patients:

• Start CPR immediately - do not wait to check temperature or rewarm 2
• Continue resuscitation until patient evaluated by advanced care - "not dead until warm and dead" 2
• Pulse check may take up to 60 seconds due to severe bradycardia 2

---

Sepsis Recognition and Management

Pathophysiology

Sepsis represents dysregulated host response to infection causing life-threatening organ dysfunction. Progression to septic shock involves profound circulatory, cellular, and metabolic abnormalities with substantially increased mortality. Cardiac arrest in sepsis results from vascular tone derangements, myocardial dysfunction, hypoxemia, acidemia, and metabolic derangements. 4

Priorities

Recognition:

• Use NEWS2 score ≥7 as high-risk threshold requiring immediate intervention 2
• Single parameter NEWS2 score of 3 should trigger clinical concern and reassessment 2
• Alert hospital for NEWS2 ≥5 in patients with suspected/confirmed infection 2

Immediate Management:

• Give antibiotics within 1 hour for high-risk patients (NEWS2 ≥7) - do not delay for investigations 2
• In remote/rural settings with transfer time >1 hour: administer antibiotics before transport according to local protocols 2
• Fluid resuscitation for hypotension with clinical shock signs (altered consciousness, decreased urine output, end-organ failure) 5
• Vasopressor/inotrope support if shock persists despite volume resuscitation 5

Critical Care Criteria:

• Refractory hypoxemia (SpO2 <90% on non-rebreather mask/FiO2 >0.85) 5
• Respiratory acidosis with pH <7.2 5
• Hypotension with shock refractory to fluids requiring vasopressors 5

Sepsis-Associated Cardiac Arrest

• Occurs in 5% of in-hospital cardiac arrests with only 17-21% survival to discharge 6
• Risk factors include: chronic pulmonary disease, unknown infection source, elevated CRP, and lactate >6 mmol/L at 6 hours 7
• Most common infection source: respiratory tract 6
• Typical presentation: deranged vital signs precede arrest, most have asystole (47%) or PEA (24%) as initial rhythm 6

---

Shock Typology

Hypovolemic Shock

Pathophysiology: Inadequate circulating volume leading to decreased preload and cardiac output.

• Fluid resuscitation is primary treatment - crystalloids initially 5
• Identify and control bleeding source in trauma 5
• Monitor response: improved mental status, urine output, blood pressure 5

Cardiogenic Shock

Pathophysiology: Primary pump failure causing inadequate tissue perfusion despite adequate volume.

• Requires inotropic support rather than aggressive fluids 5
• Identify underlying cause: myocardial infarction, arrhythmia, mechanical complication 1

Distributive Shock (Septic/Anaphylactic)

Pathophysiology: Profound vasodilation causing relative hypovolemia and maldistribution of blood flow.

• Septic shock: requires both fluids AND vasopressors, plus source control with antibiotics 2, 5
• Anaphylactic shock: requires epinephrine IM immediately, fluids, antihistamines 1

Obstructive Shock

Pathophysiology: Mechanical obstruction to cardiac output (tension pneumothorax, cardiac tamponade, massive PE).

• Requires immediate procedural intervention: needle decompression, pericardiocentesis, or thrombolysis 5
• Fluid resuscitation alone will not resolve the underlying problem 5

---

Hypoxia Typology

Hypoxemic Hypoxia (Low PaO2)

Pathophysiology: Inadequate oxygen transfer in lungs from V/Q mismatch, shunt, or diffusion impairment.

• Increase FiO2 and optimize ventilation - may require PEEP or advanced airway 5
• Criteria for critical care: SpO2 <90% on non-rebreather mask despite FiO2 >0.85 5
• Common causes: pneumonia, pulmonary edema, ARDS, pneumothorax 5

Circulatory Hypoxia

Pathophysiology: Inadequate oxygen delivery despite normal PaO2 due to low cardiac output or severe anemia.

• Treat underlying shock state - fluids, vasopressors, inotropes as indicated 5
• Consider blood transfusion for severe anemia with shock 5

Histotoxic Hypoxia

Pathophysiology: Cells cannot utilize oxygen (cyanide, carbon monoxide poisoning).

• Carbon monoxide: high-flow oxygen, consider hyperbaric oxygen for severe toxicity 2
• Cyanide: hydroxocobalamin or sodium nitrite/thiosulfate, plus high-flow oxygen 2

---

Trauma Management

Pathophysiology

Trauma causes immediate life threats through airway obstruction, tension pneumothorax, massive hemorrhage, cardiac tamponade, and traumatic brain injury. Secondary injury occurs from hypoxia, hypotension, and hypothermia. 5

Priorities

Immediate Life Threats:

• Airway with C-spine protection: assume cervical injury until excluded, especially with altered consciousness, diving mechanism, or obvious injury 2
• Breathing: identify and treat tension pneumothorax (needle decompression), flail chest, open pneumothorax 5
• Circulation: control external hemorrhage with direct pressure, identify internal bleeding requiring surgery 5

High-Risk Criteria Requiring Urgent Review:

• Penetrating injuries to head, neck, torso, extremities proximal to elbow/knee 5
• Flail chest, two or more proximal long-bone fractures 5
• Crushed/mangled/amputated extremities 5
• Pelvic fractures, open or depressed skull fractures, paralysis 5
• TRISS predicted mortality >80% 2, 5
• Patients on anticoagulation 5
• Pregnant patients >20 weeks gestation 5

Cardiac Arrest in Trauma:

• Reversible causes: hypoxia, hypovolemia, tension pneumothorax, cardiac tamponade, hypothermia 2
• Standard CPR with modifications: secure airway with C-spine protection, if bag-mask inadequate consider cricothyrotomy 2
• Do NOT transport obviously dead victims (rigor mortis, decomposition, decapitation) 2

---

Behavioral and Mental Health Emergencies

Pathophysiology

Acute mental status changes result from diverse etiologies including metabolic derangements, intoxication, withdrawal, infection, stroke, trauma, or primary psychiatric conditions. Distinguishing organic from functional causes is critical. 2

Priorities

Safety First:

• Scene safety assessment - ensure adequate personnel, remove weapons, plan escape route 2
• Physical restraint only when necessary for safety, using minimal force 2
• Chemical sedation if physical restraint insufficient - follow local protocols 2

Medical Clearance:

• Exclude life-threatening organic causes before attributing to psychiatric illness 2
• Check vital signs and glucose immediately - hypoglycemia mimics psychiatric emergency 2
• Assess for trauma, intoxication, infection using NEWS2 scoring 2
• Neuroimaging rarely indicated for isolated new-onset psychosis without focal signs, but consider for delirium with unclear etiology 2

Delirium vs Psychosis:

• Delirium: acute onset, fluctuating course, inattention, altered consciousness - suggests organic cause requiring urgent investigation 2
• New-onset psychosis: may be functional but requires exclusion of organic causes (stroke, tumor, encephalitis, metabolic) especially if focal neurologic signs present 2

High-Risk Mental Health Presentations:

• Follow local emergency protocols for acute mental health settings 2
• Arrange ambulance transfer if medical intervention needed 2
• Consider advance care planning and end-of-life wishes in decision-making 2

---

Cultural Competence Considerations

Key Principles

• Use professional interpreters for non-English speaking patients - family members may not translate accurately, especially for sensitive topics 2
• Respect cultural beliefs about medical interventions while ensuring patient safety 2
• Consider religious/cultural practices regarding blood products, end-of-life care, gender of providers 2
• Explain procedures clearly and obtain informed consent when possible, using culturally appropriate communication 2

---

Common Pitfalls to Avoid

Cardiac Arrest:

• Do not delay CPR to check temperature in hypothermia or to move patient to "better" location 2
• Do not perform abdominal thrusts on drowning victims - wastes time and causes harm 2
• Do not forget left lateral uterine displacement in pregnant patients - aortocaval compression prevents ROSC 2

Sepsis:

• Do not wait for lactate or blood cultures before giving antibiotics in high-risk patients 2
• Do not dismiss single abnormal vital sign - NEWS2 score of 3 in one parameter requires reassessment 2

Trauma:

• Do not clear C-spine clinically in unconscious, intoxicated, or distracting injury patients 2
• Do not give excessive fluids in penetrating torso trauma with maintained consciousness - permissive hypotension until hemorrhage control 5

Hypoxia:

• Do not give excessive oxygen - target SpO2 92-98%, hyperoxia increases mortality 3
• Do not assume pulse oximetry is accurate in shock states, carbon monoxide poisoning, or severe anemia 3

Mental Health:

• Do not assume psychiatric cause without excluding organic pathology - check glucose, vital signs, consider infection 2
• Do not use physical restraint alone when chemical sedation safer and more humane 2