Intraoperative Autotriggered Pressure Support Ventilation Resistant to Increased Flow Trigger Threshold.

Area of Science:

• Critical Care Medicine
• Anesthesiology
• Respiratory Physiology

Background:

• Autotriggering (AT) in mechanical ventilation occurs when the ventilator delivers breaths without patient effort, often triggered by cardiac pulsations.
• This phenomenon can lead to adverse outcomes including respiratory alkalosis, prolonged ventilation, and lung hyperinflation.
• AT is typically resolved by increasing the ventilator's flow trigger sensitivity.

Observation:

• This report details a case where autotriggering persisted despite adjusting the flow trigger to its maximum setting on a GE Datex-Ohmeda Avance S5 anesthesia station.
• The patient's cardiac pulsations were identified as the likely trigger for the persistent AT.
• This case highlights a scenario where standard AT management strategies were ineffective.

Findings:

• Standard methods to resolve autotriggering, such as increasing the flow trigger threshold, were unsuccessful in this patient.
• The GE Datex-Ohmeda Avance S5 anesthesia station exhibited a failure to resolve AT under specific conditions.
• Cardiac pulsation-induced AT can be refractory to typical ventilator adjustments.

Implications:

• Clinicians should be aware of refractory autotriggering, especially in the operating room setting.
• Further investigation may be needed to understand the mechanisms behind AT that resist standard interventions.
• This case underscores the importance of vigilant monitoring and alternative strategies for managing mechanical ventilation in complex patients.