Response surface modeling of drug interactions on cardiorespiratory control.

Causes for perioperative respiratory complications include anesthetic-and opioid-in-duced reduced ventilatory drive.1 Previous studies predominantly described the influence of single agents on the performance of the controller. Since in clinical practice an anesthetic is combined with an opioid, we designed a study on the interaction of an inhalational anes-thetic, sevoflurane, and an opioid, alfentanil, on ventilation and heart rate during normoxia and acute isocapnic hypoxia. In the next section, we first review possible methodologies to quantify pharmacodynamic interactions. Subsequently we describe the analysis of the experimental data.