Effect-Site Concentrations With Traditional Versus Patient-Controlled Opioid Dosing

(From Guignard B, Bossard AE, Coste C, et al. Acute opioid tolerance: intraoperative remifentanil increases postoperative pain and morphine requirement. Anesthesiology. 2000;93:409-417, with permission.)

After achieving effective concentrations, PCA allows patients to self-titrate opioid dosing to maintain effective analgesia. PRN, as needed.