Anaesthesia for bronchoscopy. A laboratory study using the Nuffield lung ventilator with the injector technique

Area of Science:

• Anesthesiology
• Respiratory Physiology
• Medical Device Engineering

Background:

• Automatic control of lung ventilation is crucial during bronchoscopy.
• Understanding the impact of ventilator settings on gas delivery is essential.

Purpose of the Study:

• To evaluate the Nuffield (A-P) Anaesthetic Ventilator's control module for automatic lung ventilation.
• To determine the relationship between lung mechanics, flow rate, and delivered ventilation parameters.
• To identify optimal injector settings for efficient ventilation.

Main Methods:

• Laboratory experiments were conducted using the Nuffield (A-P) Anaesthetic Ventilator.
• Ventilation was controlled automatically through a bronchoscope.
• Lung characteristics (compliance, airway resistance) and driving flow rates were manipulated.
• Oxygen concentrations and tidal volumes were measured.

Main Results:

• The ventilator's control module demonstrated efficient automatic lung ventilation.
• Specific relationships were established between lung characteristics, flow rate, and ventilation outcomes.
• A 14-gauge injector yielded the largest tidal volumes.
• The 14-gauge injector resulted in minimal entrainment of room air.

Conclusions:

• The Nuffield (A-P) Anaesthetic Ventilator control module is effective for automated bronchoscopic ventilation.
• Injector selection significantly impacts tidal volume and air entrainment.
• A 14-gauge injector is recommended for maximizing tidal volume and minimizing air entrainment during such procedures.