Vents

Objectives

1. Understand the basics of how ventilators work
2. Know how to effectively make changes to ventilator settings
3. Troubleshoot during an acute decompensation

Learning material

Basic information

Relatively concise video (13 minutes)

Peds RAP podcast (one of the free ones!) on Mechanical Ventilation Basics

More extensive Online Training via one of our featured Resources, OPENPediatrics

The basics:

• The machine itself runs in different modes. Commonly, we use SIMV (Synchronized Intermittent Mandatory Ventilation)
  • The ventilator provides a mandatory base number of ventilations per minute
  • The patient can initiate their own breaths that are supported by the ventilator
• Four our purposes as residents, vents revolve around 4 main variables that we control with the machine (there are more variables though those are usually under the purview of the respiratory therapist)
  • FiO₂
  • PEEP
  • Tidal volume
  • Respiratory rate
• We change the variables to target pH/pCO₂/HCO₃^-/pO₂, specifically pCO₂ and pO₂ to affect pH
  • pO₂
    • Affected by FiO₂ and PEEP
    • Increasing either one increases pO₂
    • ↑ FiO₂, PEEP à pO₂
  • pCO₂
    • Affected by minute ventilation
    • Minute ventilation = Tidal volume x Respiratory Rate
    • Increasing minute ventilation decreases pCO₂
    • ↑ Minute ventilation à ↓ pCO₂
• To make vent setting changes, we generally get an ABG or VBG first to guide our changes
  • The only useful information in a VBG is pH and pCO₂

When a ventilated patient acutely deteriorates don’t be a…

Dislodged ET Tube - check for equal breath sounds, EtCO2

Obstructed - Mucous plug, suction!

Pneumothorax - check for equal breath sounds, needle compression vs CXR based on relative urgency

Equipment failure - disconnect from circuit, hand bag, confirm 100% O2 is flowing