Performance of Unmodified Mechanical Ventilators With 2% Hydrogen Gas Mixtures

Area of Science:

• Critical Care Medicine
• Respiratory Therapy
• Biomedical Engineering

Background:

• Molecular hydrogen (H2) possesses antioxidant, anti-inflammatory, and anti-apoptotic properties.
• H2 may benefit ischemia-reperfusion injury and critical illnesses.
• Clinical application of H2 via mechanical ventilators requires performance evaluation.

Purpose of the Study:

• To assess the performance of unmodified mechanical ventilators when delivering 2% H2 mixtures.
• To evaluate the accuracy of tidal volume (VT) and oxygen concentration (FIO2) delivery.
• To identify potential malfunctions or inaccuracies associated with H2 administration.

Main Methods:

• Four ventilator models (Maquet Servo-i, Servo-u, Dräger Evita Infinity V500, Babylog VN500) were tested.
• Ventilators were supplied with certified 2% H2 in air/O2 mixtures.
• Measurements included delivered VT, FIO2, H2 concentration, and pre-use check outcomes across neonatal to adult settings.

Main Results:

• Maquet Servo-i, Servo-u, and Dräger Evita V500 showed acceptable accuracy (within ±10% bias) for VT and FIO2 delivery with H2.
• The Dräger Babylog VN500 exhibited significant inaccuracy in VT delivery (average bias of -89.2%) when using H2 mixtures.
• All tested ventilators, except the Babylog VN500, passed pre-use checks.

Conclusions:

• Unmodified Maquet Servo-i, Servo-u, and Dräger Evita V500 ventilators are suitable for delivering 2% H2 mixtures.
• The Dräger Babylog VN500 is unsuitable for H2 administration due to inaccurate VT delivery.
• Ventilator technology (e.g., hot-wire anemometry) impacts H2 delivery accuracy.