Study Notes: Basics of Intensive Care (ICU)

1. What is the ICU?

• ICU = Intensive Care Unit (also called Critical Care Unit or Intensive Therapy Unit).

• Specialized hospital ward for critically ill, unstable patients.

• Main purposes:

  • Treat life-threatening illnesses.

  • Support failing organ systems.

  • Prevent secondary injury.

  • Provide specialized environment with 1:1 care and continuous monitoring.

2. How ICU Differs From General Wards

• Staffing: More staff; typically 1 nurse per patient.

• Expertise: Specialized nurses, intensivists, and allied health staff.

• Monitoring: Continuous and invasive (e.g., arterial lines, ECG, ICP).

• Outcomes: Mortality increases as more organs fail (≥3 organ failures → survival 20–30%).

• Cost: Higher due to staff, equipment, and investigations.

3. ICU Admission Criteria

• Patients with organ failure and a reasonable chance of recovery.

• Types of Admission:

  • Emergency: After sudden deterioration (e.g., pneumonia, asthma, sepsis) or emergency surgery.

  • Elective: Planned monitoring/support after major surgery.

• Common Emergency Triggers:

  • Respiratory: Hypoxia, abnormal respiratory rate.

  • Cardiovascular: Hypotension, arrhythmias.

  • Renal: Oliguria/anuria.

  • Neurological: Reduced consciousness, seizures.

  • Metabolic: Severe derangements (e.g., acidosis).

4. Common Conditions Requiring ICU Care

• ARDS (Acute Respiratory Distress Syndrome): Severe lung inflammation, hypoxemia.

• Sepsis: Systemic infection → inflammatory response → multi-organ failure.

  • Diagnosed by abnormal temp, HR, RR, WBC.

  • Treated with “Sepsis Bundles” (e.g., Surviving Sepsis Campaign).

• Acute Kidney Injury (AKI): Sudden decline in kidney function (oliguria/anuria, ↑ creatinine).

5. Specialized ICU Equipment & Monitoring

• Bedside monitor: HR, BP, SpO₂, temp, etc.

• Arterial lines: Continuous BP, blood sampling.

• Ventilator: Provides oxygen & ventilation via endotracheal tube.

• IV access: Central lines for drugs, fluids, nutrition.

• Chest drains, NG tubes, urinary catheters.

• Airway suction: Removes secretions.

6. Organ Support in ICU

Respiratory Failure

• Cause: Inability to oxygenate or ventilate.

• Treatment: Mechanical ventilation (intubation + ventilator).

• Modes: From full control to pressure support as recovery begins.

Cardiovascular Failure

• Definition: Inadequate blood flow to organs.

• Equation: MAP = CO × SVR.

  • CO low → due to ↓ HR or ↓ stroke volume (e.g., heart block, myocardial damage).

  • SVR low → sepsis, anaphylaxis (vasodilation).

• Support: Vasopressors, inotropes, fluids, pacing.

Renal Failure

• Cause: Inability to excrete waste and maintain electrolytes.

• Diagnosis: Oliguria/anuria, abnormal urine studies, ↑ creatinine/urea.

• Treatment: Renal replacement therapy (hemofiltration, dialysis).

Neurological Failure

• Cause: Trauma, stroke, hypoxia, infection, metabolic derangements.

• Manifestation: Reduced consciousness, coma.

• Management:

  • Prevent secondary brain injury (reduce swelling, maintain perfusion & oxygenation).

  • Monitoring: ICP measurement when needed.

  • Ventilation if consciousness is impaired.

7. Discharge from ICU

• Once organ support can be withdrawn and patient is stable:

  • Transfer to High Dependency Unit (HDU) or regular ward.

• Recovery influenced by:

  • Severity of illness.

  • Number of organs affected.

  • Pre-existing health/fitness.

• Post-ICU complications:

  • Persistent organ dysfunction.

  • ICU-acquired weakness.

  • Psychological sequelae: depression, delirium, anxiety, PTSD.

8. Key Takeaway

ICU provides the highest level of care in the hospital:

• Specialized staff, equipment, and organ support.

• Admission for patients with critical illness but a potential for recovery.

• Focus on treating organ failure while preventing secondary injury.

• Recovery continues long after discharge, with both physical and psychological challenges.