Abstract
A middle-range theory for Chronotherapeutic Intervention in Postsurgical Pain (CIPP) is presented. This theory supports time-dependent approaches to pain assessment and intervention that may be implemented by nurses in the clinical setting. CIPP was inductively derived from chronobiologic literature and validated through investigations in three separate chronobiologic studies. A circadian rhythm in pain was identified in Study I, with 19 postsurgical gynecologic oncology patients, and validated in Study II, with 45 postsurgical patients. Study III, a randomized clinical trial of 71 gynecologic oncology patients, compared the efficacy of chronotherapeutic versus continuous fixed-rate basal and demand-only PCA therapy for postoperative pain relief.