Validation of a new respiratory inductive plethysmograph

Area of Science:

• Respiratory physiology
• Medical device validation
• Critical care monitoring

Background:

• Respiratory inductive plethysmography (RIP) monitors end-expiratory lung volume (deltaEELV) changes.
• RIP is valuable in intensive care for optimizing ventilator settings by assessing positive end-expiratory pressure (PEEP)-induced lung volume changes.

Purpose of the Study:

• Validate the newest Respitrace Plus RIP model.
• Compare its performance against a previous RIP model (Respigraph).
• Assess accuracy in measuring tidal volume (V(T)) and PEEP-induced deltaEELV.

Main Methods:

• In vitro validation using a lung model.
• In vivo evaluation in spontaneously breathing subjects, acute lung injury (ALI) patients, and anesthetized patients.
• Comparison with pneumotachometry and spirometry.

Main Results:

• The new RIP demonstrated accuracy comparable to pneumotachometry for V(T) in volunteers and ALI patients.
• In anesthetized patients, a statistically significant PEEP-device interaction was observed for acute deltaEELV measurements.
• The new RIP exhibited significant baseline drift in vitro, especially at varying temperatures, compared to the older model.

Conclusions:

• The Respitrace Plus is suitable for clinical and research V(T) measurements.
• Semiquantitative acute deltaEELV measurements are clinically accurate, but long-term monitoring is limited.
• Extended device warm-up is recommended to mitigate drift for accurate measurements.