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Although an extensive number of studies have attempted to identify predictors of new-onset atrial fibrillation (AFIB) after coronary artery bypass grafting (CABG), a strong predictive model does not exist. Prior studies have included patients recruited from multiple centers with variant AFIB prevalence rates and those who underwent CABG in combination with other surgical procedures. Also, most studies have focused on pre- and perioperative characteristics, with less attention given to the initial postoperative period. The purpose of this study was to comprehensively examine pre-, peri-, and postoperative characteristics that might predict new-onset AFIB in a large sample of patients undergoing isolated CABG in a single medical center, utilizing data readily available to clinicians in electronic data repositories. In addition, length of stay and selected postoperative complications and disposition were compared in patients with AFIB and no AFIB.Retrospective, comparative survey.University-affiliated tertiary care hospital.Patients with new-onset AFIB who underwent isolated standard CABG or minimally invasive direct vision coronary artery bypass were identified from an electronic clinical data repository.None.The prevalence of AFIB in the total sample (n = 814) was 31.9%. Predictors of AFIB included age (p =.0004), number of vessels bypassed (p =.013), vessel location (diagonal [p.003] or posterior descending artery [p.001]), and net fluid balance on the operative day (p =.015). Forward stepwise regression analysis produced a model that correctly predicted AFIB in only 24% of cases, with age (14%) and body surface area (9%) providing the most prediction. The incidence of embolic stroke was higher in AFIB (n = 8) vs. no AFIB (n = 4) patients, but stroke preceded AFIB onset in seven of eight cases. Subjects with AFIB had a longer stay (p =.0004), more intensive care unit readmissions (p =.0004), and required more assistance at hospital discharge (p =.017).Despite attempts to examine comprehensively predictors of new-onset AFIB, we were unable to identify a robust predictive model. Our findings, in combination with prior work, imply that it may not be feasible to predict the development of new-onset AFIB after CABG using data readily available to the bedside clinician. In this sample, stroke was uncommon and, when it occurred, preceded AFIB in all but one case. As anticipated, AFIB increased length of stay, and patients with this complication required more assistance at discharge.

Objective: The major benefit of tracheal gas insufflation (TGI) is an increase in CO 2 elimination efficiency by removal of CO 2 from the anatomical deadspace. In conjunction with mechanical ventilation, TGI may also alter variables that affect CO 2 elimination, such as minute ventilation and peak airway pressure (peak Paw) and cause the development of auto-positive end-expiratory pressure (auto-PEEP). We tested the hypothesis that TGI-induced auto-PEEP alters ventilatory variables. We predicted that TGI-induced auto-PEEP offsets the beneficial effects of TGI on CO 2 elimination and that keeping total PEEP (ventilator PEEP + auto-PEEP) constant enhances the CO 2 elimination efficiency afforded by TGI. Design: Prospective study of two series of patients with acute respiratory distress syndrome receiving mechanical ventilation. Setting: Intensive care units at a university medical center. Patients: Each series consisted of eight sequential hypercapnic patients. Interventions: In series 1, we examined the effect of continuous TGI at 0 and 10 L/min on Paco 2 , without compensating for the development of auto-PEEP. In series 2, we examined this same effect of continuous TGI while reducing ventilator PEEP to keep total PEEP constant. TGI-induced auto-PEEP was calculated based on dynamic compliance measurements during zero TGI flow conditions (ΔV/ΔP) after averaging the two baseline values for peak Paw and tidal volume and assuming compliance did not change between the zero TGI and TGI flow conditions (ΔV TGI /ΔP TGI ). Measurements and Main Results: In series 1, total PEEP increased from 13.2 ± 3.2 cm H 2 O to 17.8 ± 3.5 cm H 2 O without compensation for auto-PEEP (P =.01). Paco 2 decreased (P =.03) from 56.2 ± 10.6 mm Hg (zero TGI) to 52.9 ± 9.3 mm Hg (TGI at 10 Umin), a 6% decrement. In series 2, total PEEP was unchanged (p = NS). Paco 2 decreased (p =.03) from 59.5 ± 10.4 mm Hg (zero TGI) to 52.2 ± 8.3 mm Hg (TGI at 10 L/min), a 12% decrement. There was no significant change in Pao 2 there were no untoward hemodynamic effects in either series, Conclusions: These data are consistent with the hypothesis that mechanical ventilation + TGI causes an increase in auto-PEEP that can blunt CO 2 elimination. In addition to the ventilator modifications necessary to keep ventilatory variables constant when TGI is used, it is also necessary to reduce ventilator PEEP to keep total PEEP constant and further enhance CO 2 elimination efficiency.