Physiological measurement
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Physiological measurement · Sep 2013
The dynamics of carbon dioxide equilibration after alterations in the respiratory rate.
Manual or automated control of mechanical ventilation can be realized as an open or closed-loop system for which the regulation of the ventilation parameters ideally is tuned to the dynamics and equilibration time of the biological system. We investigated the dynamic, transient state and equilibration time (teq) of the CO2 partial pressure (PCO2) after changes in the respiratory rate (RR). ⋯ Extrapolation of the transition between two PCO2 steady-states allowed for the prediction of the new PCO2 steady-state as early as 0.5 teq with an error <4 mmHg. At bedside or in automated ventilation systems, the linear dependencies between ΔRR and ΔPCO2 and between ΔRR and teq as well as early steady-state prediction of PCO2 could be used as a guidance towards a timing and step size regulation of RR that is well adapted to the biological system.