Unexplained in-hospital fever following cardiac surgery. Natural history, relationship to postpericardiotomy syndrome, and a prospective study of therapy with indomethacin versus placebo.

In Part I of this study, the in-hospital course of 219 patients who had undergone a cardiac operation is analyzed. Fever (greater than or equal to 37.8 degrees C, rectal) was present after postoperative day 6 in 159 patients (73%) and was of unexplained cause in 118. Fever decay in the population of unexplained fever patients was exponential. All patients with unexplained postoperative fever were afebrile by postoperative day 19. In-hospital pericardial rub and pleuritic chest pain, widening of the mediastinum on chest film, and pleural effusion were not specifically associated with unexplained postoperative fever. In Part II, 67 patients with unexplained postoperative fever were given indomethacin (100 mg per day) or placebo for 7 days by a randomized, double-blind protocol. Indomethacin resulted in a shorter duration of fever (2.4 vs 3.5 days, P is less than 0.01) and in a shorter duration of chest pain, malaise, and myalgias compared to placebo. Sixty-seven percent of the patients in Part I and all of the patients in Part II were contacted 2-8 months following hospital discharge. Five percent had experienced an illness that we considered to be acute pericarditis, but its occurrence was unrelated to whether the patient had had in-hospital unexplained postoperative fever, in-hospital rub or chest pain, or in-hospital administration of indomethacin.