The pharmacodynamic effect of a remifentanil bolus on ventilatory control.

Background: In doses typically administered during conscious sedation, remifentanil may be associated with ventilatory depression. However, the time course of ventilatory depression after an initial dose of remifentanil has not been determined previously.

Methods: In eight healthy volunteers, the authors determined the time course of the ventilatory response to carbon dioxide using the dual isohypercapnic technique.

Diphenylhydramine increases ventilatory drive during alfentanil infusion.

Background: Diphenhydramine is used as an antipruritic and antiemetic in patients receiving opioids. Whether it might exacerbate opioid-induced ventilatory depression has not been determined.

Methods: The ventilatory response to carbon dioxide during hyperoxia and the ventilatory response to hypoxia during hypercapnia (end-tidal pressure of carbon dioxide [PETCO2] is approximately equal to 54 mmHg) were determined in eight healthy volunteers.

Propofol depresses the hypoxic ventilatory response during conscious sedation and isohypercapnia.

Background: Propofol infusion at subanesthetic doses provides reliable conscious sedation. However, the ventilatory effects of sedative doses of propofol have not been established. The current study was conducted to determine the effects of propofol sedation on the hypoxic ventilatory response.