An interchangeable Mapleson A-E breathing system is practical and cost effective

Area of Science:

• Anesthesiology
• Respiratory System Engineering
• Medical Device Modification

Background:

• Limited oxygen and anesthesia gas supplies necessitate reduced fresh gas flow (FGF) during inhalational anesthesia.
• Circle systems are often impractical in resource-limited environments.
• Investigating modifications to transport breathing apparatus for improved gas efficiency is crucial.

Purpose of the Study:

• To evaluate the interchangeability between Mapleson D (Map-D) and Mapleson A (Map-A) configurations using a common transport breathing apparatus.
• To determine if the Map-A configuration can eliminate carbon dioxide (CO2) rebreathing at lower FGF rates compared to Map-D.

Main Methods:

• A standard Map-D transport system was converted to a Map-A system by repositioning the exhaust valve and fresh gas delivery point.
• Comparison of Map-A and Map-D systems was performed under a structured protocol.
• Key metrics included FGF, FGF/minute ventilation (V(E)), and physiological variables.

Main Results:

• The Map-A configuration achieved a mean decrease in FGF of 2.8 L/min compared to Map-D (P=0.003).
• FGF/V(E) was significantly lower with Map-A (1.1) versus Map-D (1.8) (P=0.007) without affecting physiologic or anesthetic variables.
• The reduction in FGF achievable by switching systems correlated with patient respiratory rate (r=0.45, P<0.01).

Conclusions:

• Modification of breathing systems to achieve Mapleson A configuration can significantly reduce fresh gas flow requirements.
• This modification offers potential for cost and resource savings in clinical settings.
• Appropriate ventilation can be maintained at lower FGF rates, enhancing efficiency.