Overview of the Anesthesia Machine

Introduction

Presenter: Max Binstein, Anesthesiologist at Mount Sinai Hospital, NYC

Focus: Tour and explanation of the anesthesia machine, a critical yet often overlooked component in the OR.

Anesthesiologist's Priorities

• Delivering oxygen to patient’s vital organs.
• Ensuring patient comfort.

Oxygen Supply and Safety Features

• Oxygen Source: Central storage system in the hospital.

  • Piped into the OR via wall or ceiling.
  • Anesthesiologists must understand the gas plumbing for troubleshooting.

• Pressure and Backup Tanks:

  • Oxygen is supplied at 50 PSI.
  • Backup tanks: Green for oxygen, yellow for medical air.

Anesthesia Machine Components and Functions

• Bellows System:

  • Drives gas mixture through the circuit.
  • Can be pneumatic or electronic.

• Vaporizer:

  • Adds anesthetic gas to the circuit.

• Circle Anesthesia Circuit:

  • One-way valves prevent backward gas flow.
  • Inspiratory limb delivers gas to patient.
  • CO2 absorber removes CO2 from exhaled gas.
  • Purple waste line disposes of used gas.

• Heat and Moisture Exchanger:

  • Maintains patient’s exhaled heat and moisture.
  • Crucial for temperature maintenance, especially in pediatric patients.

Manual Controls and Safety Features

• E Cylinders:

  • High pressure (2200 PSI) backup tanks.
  • Pressure regulated down to 45 PSI within the machine.
  • Manual opening/closing to prevent leaks.

• Auxiliary Ports:

  • For nasal cannulas or face masks.

• Bag to Vent Switch:

  • Toggles between spontaneous bag ventilation and ventilator mode.

• Oxygen Flush Valve:

  • Delivers quick bursts of oxygen at high flow rates (up to 75 L/min).

• APL Valve:

  • Adjustable pressure limiting valve.
  • Protects patient lungs by releasing excess pressure.
  • Useful for troubleshooting breathing issues.

Circuit Connections and CO2 Absorption

• Standardized Connection Sizes:

  • Allows switching between face masks and endotracheal tubes.

• CO2 Absorber:

  • Eliminates CO2, allowing the rebreathing of exhaled gases.
  • Limited lifetime; change indicated by color change or rising end-tidal CO2.

Ventilator Controls

• Ventilator Screen:

  • Displays parameters like fraction of inspired oxygen, flow rates, and volatile anesthetic levels.

• Ventilator Modes:

  • Volume control and pressure control.
  • Pressure support ventilation.

• Monitoring Information:

  • Peak airway pressures, tidal volumes, CO2 (end-tidal), O2 levels, and anesthetic gas levels.

Additional Monitoring Tools

• Screens Attached to Workstation:
  • Main ventilator screen.
  • Patient monitors (e.g., processed EEG monitor, regional oximetry device).
  • Computer for electronic anesthesia records.

Closing

• Anesthesia machine overview is superficial; thorough understanding requires extensive training.
• Additional videos on cardiac anesthesia setup and patient monitors are available.