Introduction to Critical Care

ICU Monitoring Parameters 

Learning Objectives

By the end of this session, you should be able to:

• Define critical care and understand the role of the ICU
  
  

• Identify common indications for ICU admission
  
  

• Understand monitoring and organ support in ICU
  
  

• Learn principles of sedation and analgesia in critically ill patients
  
  

• Recognise the importance of infection control and nutrition
  
  

What is Critical Care?

Critical care is the comprehensive, continuous care of critically ill patients who are at risk of or recovering from life-threatening organ failure.
This care is delivered in an Intensive Care Unit (ICU) or High Dependency Unit (HDU).

Common Indications for ICU Admission

1. Respiratory failure
   
   

   • Need for mechanical ventilation (e.g. ARDS, pneumonia, COPD)
     
     

2. Cardiovascular instability
   
   

   • Requiring vasopressors/inotropes (e.g. septic shock, MI)
     
     

3. Neurological impairment
   
   

   • GCS ≤ 8, seizures, stroke, traumatic brain injury
     
     

4. Multiorgan failure
   
   

5. Postoperative monitoring
   
   

   • Especially after major surgery or massive blood loss
     
     

6. Severe metabolic derangement
   
   

   • DKA, HHS, severe acidosis
     
     

7. Sepsis
   
   

Levels of Critical Care

Level

Description

Level 0

Standard ward care

Level 1

Patients at risk of deterioration (HDU)

Level 2

Single organ support (e.g. NIV, inotropes)

Level 3

Multiple organ support (e.g. mechanical ventilation + vasopressors) – full ICU

ICU Monitoring Parameters

Category

Parameters

Cardiovascular

HR, BP (invasive/non-invasive), CVP, MAP

Respiratory

SpO₂, RR, PaO₂/PaCO₂, ventilator parameters

Neurological

GCS, pupil size/reactivity, EEG if indicated

Renal

Urine output (>0.5 mL/kg/hr), urea/creatinine

Metabolic

Blood glucose, electrolytes, lactate

Temperature

Continuous or intermittent monitoring

Others

Arterial blood gases (ABG), ECG, fluid balance charts

Organ Support in ICU

1. Respiratory Support

• Oxygen therapy
  
  

• Non-invasive ventilation (NIV) – CPAP, BiPAP
  
  

• Mechanical ventilation
  
  

  • Modes: Volume/pressure control, SIMV, pressure support
    
    

  • PEEP to maintain alveolar patency
    
    

2. Cardiovascular Support

• Vasopressors:
  
  

  • Noradrenaline: 0.05–1 mcg/kg/min IV (1st line in septic shock)
    
    

  • Adrenaline: 0.05–2 mcg/kg/min IV
    
    

  • Phenylephrine: 0.1–0.5 mcg/kg/min IV
    
    

• Inotropes:
  
  

  • Dobutamine: 2–20 mcg/kg/min (esp. in heart failure)
    
    

  • Dopamine: dose-dependent action
    
    

3. Renal Support

• Maintain fluid balance
  
  

• Monitor urine output
  
  

• Dialysis/CRRT for renal failure
  
  

Sedation and Analgesia in ICU

Goals:

• Ensure patient comfort
  
  

• Facilitate mechanical ventilation
  
  

• Reduce anxiety, pain, agitation
  
  

Common Sedatives:

Drug

Dose

Notes

Midazolam

0.02–0.1 mg/kg/hr

Short-acting benzodiazepine

Propofol

0.5–4 mg/kg/hr

Rapid onset, hypotension risk

Dexmedetomidine

0.2–0.7 mcg/kg/hr

Alpha-2 agonist, mild analgesia, minimal resp. depression

Analgesics:

• Fentanyl: 1–2 mcg/kg/hr IV
  
  

• Morphine: 2–5 mg IV bolus, or infusion 0.5–2 mg/hr
  
  

• Paracetamol: 1 g IV every 6 hours
  
  

Always assess with sedation scales (e.g. RASS) and titrate to effect.

Nutrition in ICU

• Start enteral nutrition within 24–48 hours if gut is functional
  
  

• Parenteral nutrition if enteral not possible
  
  

• Monitor:
  
  

  • Calories
    
    

  • Proteins
    
    

  • Electrolytes and blood glucose
    
    

Infection Prevention in ICU

• Strict hand hygiene
  
  

• Aseptic technique during catheter insertion
  
  

• Daily review of:
  
  

  • Lines (central/peripheral)
    
    

  • Urinary catheters
    
    

  • Antibiotics
    
    

• Ventilator-Associated Pneumonia (VAP) prevention:
  
  

  • Head elevation 30–45°
    
    

  • Oral care
    
    

  • Regular suctioning
    
    

Ethical Considerations

• Informed consent
  
  

• Discuss goals of care and prognosis
  
  

• End-of-life decisions (e.g. DNR orders, withdrawal of care)