Prospective trial of thoracic and spine surgeons' updating of their estimated case durations at the start of cases.

BACKGROUND: Surgeon estimates of case durations are important for operating room (OR) management decision making because many cases are rare combinations of procedures with few or no historical data. Thoracic and spine surgeons updated their scheduled OR times on the day of surgery just before the "time out" in the OR. METHODS: All elective (scheduled) general thoracic (n = 39) and spine surgery (n = 48) cases at 1 hospital were studied over 3-month and 1.5-month periods, respectively. RESULTS: Among cases with a change in predicted duration, most changes were made based on updates to the surgical or anesthetic procedures (thoracic 85%, spine 86%). For thoracic surgery, there was overall no significant median reduction in absolute prediction error (median 0 minutes, 95% confidence interval [CI] 0-0 minutes). Among the 37% of cases with changed predicted durations, there was a significant reduction in absolute error (median 38 minutes, 95% CI >7.5 minutes). For spine surgery, there was overall no reduction in the absolute error (median 0 minutes, 95% CI 0-0 minutes). Among the 29% of cases with changed predicted durations, absolute error was no worse, but not significantly better (point estimate of median reduction 34 minutes, 95% CI >0 minutes). Secondary observations made were no effect of updates on bias, frequent rounding of scheduled durations to the nearest half hour, and increased predictive error caused by decisions that reduced expected overutilized OR time. CONCLUSIONS: A systematic program of routinely and/or always asking for updated case duration predictions will not substantively improve OR management decision making. However, when a change in surgical approach, surgical procedure, or anesthetic procedure is identified (e.g., at the intraoperative briefing before case start), the updated estimate of case duration should be used, because such updates are not worse and often better than original estimates.

Left versus right atrial difference in dominant frequency, K(+) channel transcripts, and fibrosis in patients developing atrial fibrillation after cardiac surgery.

BACKGROUND: The development of atrial fibrillation (AF) after cardiac surgery is associated with adverse outcomes; however, the mechanism(s) that trigger and maintain AF in these patients are unknown. OBJECTIVE: The purpose of this study was to test our hypothesis that postoperative AF is maintained by high-frequency sources in the left atrium (LA) resulting from ion channel and structural features that differ from the right atrium (RA). METHODS: Forty-four patients with no previous history of AF who underwent cardiac surgery consented to LA and RA biopsies. Histologic sections evaluated fatty infiltration, fibrosis, and iron deposition; quantitative reverse transcription-polymerase chain reaction (RT-PCR) assessed ion channel expression. In a subset of 27 patients, LA and RA unipolar recording leads were also placed. In patients who developed AF, the dominant frequency (DF) for each lead was calculated using fast Fourier transform. RESULTS: DFs during AF were LA 6.26 +/- 0.8 Hz, RA 4.56 +/- 0.7 Hz (P <.01). RT-PCR revealed LA-to-RA differences in mRNA abundance for Kir2.3 (1.8:1) and Kir3.4 (2.3:1). While LA fibrosis was greater in patients developing AF compared with those remaining in normal sinus rhythm (10.8% +/- 11% vs. 3.8% +/- 3.5%; P = .03), the amount of LA fibrosis inversely correlated with the LA DF. CONCLUSIONS: This is the first demonstration of LA-to-RA frequency differences during postoperative AF, which are associated with LA-to-RA differences in mRNA levels for potassium channel proteins and LA fibrosis. These results strongly suggest that sources of AF after cardiac surgery are located in the LA and are stabilized by LA fibrosis.