Patient-ventilator interaction during noninvasive positive pressure ventilation.

Area of Science:

• Respiratory Medicine
• Critical Care Medicine
• Biomedical Engineering

Background:

• Patient-ventilator interaction is complex in semi-open systems like noninvasive ventilation (NIV).
• Air leaks around the mask are common in NIV, significantly impacting patient-ventilator synchrony.
• Mismatches between neural respiratory output and ventilator assistance can occur, particularly with pressure support ventilation (PSV).

Purpose of the Study:

• To explore factors influencing patient-ventilator synchrony during NIV.
• To identify strategies for improving patient tolerance and synchrony during NIV.
• To discuss the role of ventilator settings, interfaces, and types in managing NIV.

Main Methods:

• Review of variables affecting synchrony in NIV, including leaks, trigger sensitivity, and cycling mechanisms.
• Analysis of different ventilation modes, such as PSV and proportional assist ventilation (PAV).
• Consideration of interface selection and ventilator technology (turbine- or piston-based) for leak compensation.

Main Results:

• Air leaks are a primary cause of asynchrony, leading to variations in inspiratory effort.
• Time cycling termination may improve synchrony compared to flow cycling.
• High pressurization rates can negatively impact compliance.

Conclusions:

• Optimizing ventilatory settings and interfaces is key to achieving better patient-ventilator synchrony in NIV.
• Turbine- or piston-based ventilators are recommended for their ability to compensate for air leaks.
• Sedation strategies should focus on environmental optimization and judicious use of low-dose analgesics and neuroleptics when necessary.