Cardiopulmonary Resuscitation & Life Support – Comprehensive Study Notes

Cardiopulmonary Resuscitation (CPR)

• Definition: An emergency procedure performed when a person’s heart stops beating and no pulse is detected.
  • Chest compressions artificially circulate blood in the absence of a spontaneous heartbeat.
  • Goal: Maintain oxygenated blood flow to the brain and vital organs until spontaneous circulation is restored.
• Contextual example: A bystander finds an adult collapsed, unresponsive, pulseless → CPR is indicated immediately.
• Ethical / Legal significance:
  • Many regions have Good-Samaritan laws protecting rescuers acting in good faith.
  • Healthcare professionals are held to a duty‐to‐act standard if on duty.

CPR Standards & Evidence Base

• The American Heart Association (AHA) publishes, reviews, and revises CPR guidelines.
  • All recommendations are science- and evidence-driven, updated every 5 years or sooner when compelling data emerge.
• Impact Statistic: Early CPR can double or triple survival after cardiac arrest.
  • Expressed numerically: 2\times to 3\times increase in out-of-hospital survival odds.
• Historical note: Survival improvements are credited to the continual refinement of compression depth, rate, and early defibrillation.

AHA “Chain of Survival”

• A conceptual roadmap linking critical, time-sensitive actions:
  1. Activation of Emergency Response
  2. High-Quality CPR
  3. Defibrillation
  4. Advanced Resuscitation
  5. Post-Cardiac Arrest Care
  6. Recovery
• Mnemonic seen in slide (BROREA) corresponds to each step sequentially.
• Clinical pearl: Breakdown at any link markedly decreases neurologically intact survival.

Activate Emergency Response Team

• Primary action: Call 911 (United States) or local EMS number.
  • Delegation: Assign one team member exclusively to call or trigger Rapid Response / Code Blue.
• Rationale: Professional rescuers bring equipment (AED, medications) and definitive care.

High-Quality CPR (HQ-CPR)

• For trained rescuers (health-care providers): “Conventional CPR” = compressions + breaths.
  • Compression-to-ventilation ratio: 30:2 for adults.
  • Compression rate: 100\text{–}120\,\text{min}^{-1}.
  • Compression depth: at least 2\,\text{in} (≈5\,\text{cm}) but <2.4\,\text{in} (≈6\,\text{cm}).
• Five critical components (apply to trained & untrained):
  • Minimize interruptions (<10\,\text{s} ideally).
  • Provide adequate rate & depth.
  • Full chest recoil (avoid leaning).
  • Correct hand placement (lower half of sternum).
  • Avoid excessive ventilation (no hyperinflation; ~1 sec per breath).
• Hypothetical scenario: Stopping compressions for a rhythm check >20\,\text{s} can cut coronary perfusion pressure in half, delaying ROSC (return of spontaneous circulation).

Automated External Defibrillators (AED)

• AED presence can raise survival rates substantially when used within the first 3 minutes of collapse.
• AHA stance: Deployment should not be limited to trained personnel, but training enhances speed & accuracy.
• Community implication: Placing AEDs in airports, malls, and schools bridges the time gap before EMS arrival.

Defibrillation Sequence (Adult Unwitnessed Arrest)

1. Verify unresponsiveness & pulselessness (carotid check ≤10\,\text{s}).
2. Power on AED.
3. Expose chest, remove moisture/medication patches.
4. Apply pads (sternal–apical configuration).
5. Stop compressions → Device analyzes rhythm.
6. If “Shock Advised,” deliver shock (ensure “All clear!”).
7. Resume CPR immediately for 2\,\text{min} before next rhythm check.
8. Repeat cycle until ROSC or termination of efforts.

Advanced Resuscitation

• Performed by ACLS-trained providers once airway & drugs are available.
  • Endotracheal intubation / supraglottic airway for definitive ventilation.
  • Mechanical chest-compression devices (e.g., LUCAS) maintain consistent depth/rate, useful in transport or cath-lab.
• Significance: Frees personnel for other tasks (IV access, drug prep) and decreases variability.

Recovery Position (Post-ROSC or Breathing, Unconscious Patient)

• Steps (lateral, side-lying to protect airway):
  1. Remove eyewear / bulky items.
  2. Extend near arm 90^{\circ} from body, palm up.
  3. Cross far arm, back of hand on cheek.
  4. Flex far knee 90^{\circ}.
  5. Roll patient toward you using knee leverage.
  6. Slight head tilt to keep airway open.
  7. Face angled downward for fluid drainage.
  8. Continually monitor breathing & pulse until EMS assumes care.
• Real-world importance: Low-tech maneuver preventing aspiration in opioid overdoses, seizures, intoxicated individuals.

Basic Life Support (BLS)

• Mandatory certification for most healthcare personnel (nurses, EMT-B, physicians in training).
• Curriculum components:
  • Adult, child, infant compressions.
  • Rescue breathing (with barrier devices).
  • Choking relief (Heimlich/abdominal thrusts).
• Foundation for all subsequent resuscitation credentials (ACLS, PALS).

Advanced Cardiac Life Support (ACLS)

• Builds on BLS core but integrates:
  • Cardiac rhythm interpretation.
  • Pharmacological interventions to correct pulseless arrhythmias.
  • Team leadership & communication.

ACLS 5 H’s & 5 T’s (Reversible Causes of Arrest)

• H-Causes
  1. Hypovolemia – e.g., massive GI bleed → fluid/blood resuscitation.
  2. Hypoxia – airway obstruction → oxygenation/intubation.
  3. Hydrogen ion (Acidosis) – severe DKA → bicarbonate/ventilation.
  4. Hyper/Hypokalemia – dialysis patient with K^{+} >6.5\,\text{mEq L}^{-1} → calcium, insulin/glucose.
  5. Hypothermia – core <35^{\circ}\text{C} → rewarming before pronouncing death.
• T-Causes
  1. Toxins – opioid overdose → naloxone.
  2. Cardiac Tamponade – pericardiocentesis.
  3. Tension Pneumothorax – needle decompression at 2^{\text{nd}} ICS MCL.
  4. Thrombosis (Coronary) – STEMI → PCI.
  5. Thrombosis (Pulmonary) – massive PE → thrombolytics.
• Clinical relevance: Identifying & reversing these causes can restore a perfusing rhythm.

ACLS Medications (Selected)

• Antiarrhythmics
  • Adenosine – for stable SVT; dose 6\,\text{mg} rapid IV push, may repeat 12\,\text{mg}.
  • Amiodarone – for VF/pVT unresponsive to shocks; 300\,\text{mg} IV bolus, then 150\,\text{mg}.
  • Lidocaine, Magnesium (torsades), Atropine (bradycardia).
• Pressors & Vasoconstrictors
  • Epinephrine 1\,\text{mg} IV/IO every 3\text{–}5\,\text{min} (pulseless).
  • Dopamine, Norepinephrine, Vasopressin – post-ROSC hypotension support.
• Pharmacologic principle: Drugs support—not replace—high-quality CPR & defibrillation.

Ethical, Philosophical & Practical Considerations

• Do-Not-Resuscitate (DNR) orders must be honored; performing CPR contrary to patient wishes is assault.
• Resource Allocation: Mechanical CPR devices vs. manpower in rural EMS systems.
• Public Health: Mandating AEDs in schools parallels fire-extinguisher legislation; cost–benefit shows lives saved per \text{USD} spent is favorable.
• Psychological Recovery: Post-arrest survivors often experience cognitive deficits; early neuro-rehabilitation improves quality of life.

Connections to Foundational Principles & Other Lectures

• Ties to cardiovascular physiology: CPR maintains MAP (mean arterial pressure) via external compression, echoing Starling’s law.
• Links with respiratory mechanics: Over-ventilation raises intrathoracic pressure, lowering venous return → reinforces “avoid excessive ventilation” rule.
• Integration with pharmacology: Sympathomimetics (epinephrine) act on \alpha_{1} receptors → peripheral vasoconstriction → augmented cerebral perfusion.

Real-World Scenarios & Metaphors

• Metaphor: “CPR is like being a temporary heart and lungs.” You physically pump and ventilate, buying time for definitive interventions (defibrillation/drugs).
• Hospital code team: Analogous to a pit crew—each member (compressor, airway, monitor/defibrillator, recorder) has a defined role to minimize “pit stop” time.

References

• American Heart Association (2024). Basic Life Support.
• American Heart Association (2024). Advanced Cardiac Life Support.