Understanding Mechanical Ventilation Basics

Oct 4, 2024

Review flashcards

Basics of Mechanical Ventilation

Objectives

  • Choose a basic ventilator mode
  • Set initial ventilator settings for a patient
  • Adjust ventilator settings based on patient needs
  • Facilitate communication with healthcare providers and advance learning

Basic Ventilator Settings

  • Mode
  • Tidal Volume (in cc's)
    • Volume displaced between inhalation and exhalation
    • Based on ideal body weight (height-based)
    • Typically 6-8 cc/kg of ideal body weight
    • Formulas for predicting body weight
      • Males: 50 + 2.3 × (height in inches - 60)
      • Females: 45.5 + 2.3 × (height in inches - 60)
  • Respiratory Rate
    • Number of breaths per minute
    • Normal: 10-14 breaths/min
    • Minute ventilation = Tidal Volume × Respiratory Rate
  • FiO2 (Inspired Oxygen Concentration)
    • Start at 100% and titrate down
    • Goal: PaO2 > 60 mmHg or O2 saturation > 90%
  • PEEP (Positive End-Expiratory Pressure)
    • Positive pressure applied to airway
    • Helps alveolar recruitment
    • CPAP vs. PEEP

Ventilator Settings Adjustments

  • Based on:
    • Respiratory compliance
    • Gas exchange (measured by arterial blood gases)
  • Arterial Blood Gas Analysis: pH, PaCO2, PaO2
    • Example of respiratory acidosis: high PaCO2, low pH
    • Example of hypoxemia: low PaO2
  • Changes based on blood gases
    • For CO2 issues: adjust minute ventilation (respiratory rate or tidal volume)
    • For O2 issues: adjust FiO2 or PEEP

Blood Gas Monitoring

  • Arterial blood gases
  • N-Tidal CO2 (ETCO2)
  • Pulse oximetry
  • Hemoglobin dissociation curve: O2 saturation of 90% = PaO2 of 60 mmHg

Modes of Ventilation

  • Differences in how minute ventilation is delivered
  • Controlled Modes
    • Volume Control: set tidal volume
    • Pressure Control: set inspiratory pressure
  • Hybrid Modes
    • Assist Control Volume Control (ACVC)
    • Synchronized Intermittent Mandatory Ventilation Volume Control (SIMVVC)
    • Assist Control Pressure Control (ACPC)
    • Synchronized Intermittent Mandatory Ventilation Pressure Control (SIMVPC)
  • Spontaneous Modes
    • Pressure Support Ventilation

Reporting Ventilator Settings

  • Report settings and measured variables:
    • Volume control: tidal volume, respiratory rate, airway pressures
    • Pressure control: inspiratory pressure, respiratory rate, tidal volume

Summary

  • Basic ventilator settings and adjustment strategies
  • Controlled vs. spontaneous ventilation
  • Volume vs. pressure modes
  • Setting initial ventilator settings and adjustments based on patient needs
  • Understanding mechanical ventilation

Conclusion: Managing mechanical ventilation requires understanding basic settings, modes, and adjustments, which can enhance patient care and communication with healthcare providers.