Cameco anaesthetic ventilator with a modified Mapleson D circuit

Area of Science:

• Anesthesiology
• Medical Engineering
• Neurosurgery

Background:

• Neuroradiological procedures require general anesthesia, often limiting patient mobility.
• Standard anesthetic circuits can restrict movement, posing challenges during imaging.
• The Mapleson D circuit is a common anesthetic delivery system.

Purpose of the Study:

• To evaluate a modified Mapleson D circuit for enhanced patient mobility during general anesthesia in neuroradiological procedures.
• To assess the impact of varying tubing lengths on patient ventilation and blood gas parameters.
• To determine the reliability of this system for maintaining target carbon dioxide levels.

Main Methods:

• A modified Mapleson D circuit connected to a Cameco anesthetic ventilator was used.
• Two or three lengths of corrugated rubber tubing were employed to connect the patient.
• Blood gas analysis (Paco2, Po2) was performed on 20 patients at steady-state ventilation.
• Respiratory minute volume and fresh gas flow were set according to Bain's predictions.

Main Results:

• No significant differences in Paco2 or Po2 were observed between using two or three tubing lengths.
• Mean Paco2 values were slightly higher than those reported by Bain (0.37 kPa s.d. 0.50).
• The system facilitated increased patient mobility during radiological procedures.

Conclusions:

• The modified Mapleson D circuit system allows for maximum patient mobility during neuroradiological procedures.
• The system provides reliable adjustment of Paco2, even in patients with elevated intracranial pressure.
• This setup offers a practical solution for anesthetic management in specialized imaging.