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Computer simulation has played a pivotal role in analyzing alternative organ allocation strategies in transplantation. The current approach to producing cohorts of organ donors and candidates for individual-level simulation requires directly re-sampling retrospective data from a transplant registry. This historical data may reflect outmoded policies and practices as well as systemic inequities in candidate listing, limiting contemporary applicability of simulation results. We describe the development of an alternative approach for generating synthetic donors and candidates using hierarchical Bayesian network probability models. We developed two Bayesian networks to model dependencies among 10 donor and 36 candidate characteristics relevant to waitlist survival, donor-candidate matching, and post-transplant survival. We estimated parameters for each model using Scientific Registry of Transplant Recipients (SRTR) data. For 100 donor and 100 candidate synthetic populations generated, proportions for each categorical donor or candidate attribute, respectively, fell within one percentage point of observed values; the interquartile ranges (IQRs) of each continuous variable contained the corresponding SRTR observed median. Comparisons of synthetic to observed stratified distributions demonstrated the ability of the method to capture complex joint variability among multiple characteristics. We also demonstrated how changing two upstream population parameters can exert cascading effects on multiple relevant clinical variables in a synthetic population. Generating synthetic donor and candidate populations in transplant simulation may help overcome critical limitations related to the re-sampling of historical data, allowing developers and decision makers to customize the parameters of these populations to reflect realistic or hypothetical future states. [ABSTRACT FROM AUTHOR]

Purpose Atrial arrhythmias are common after non-cardiac thoracic surgery. We tested the hypothesis that TEA reduces the risk of new-onset atrial arrhythmias after pulmonary resection. Methods We evaluated patients who had pulmonary resection. New-onset atrial arrhythmias detected before hospital discharge was our primary outcome. Secondary outcomes included other cardiovascular complications, pulmonary complications, time-weighted average pain score over 72 h, and duration of hospitalization. Patients with combination of general anesthesia and TEA were matched on propensity scores with patients given general anesthesia only. The matched groups were compared by use of logistic regression, linear regression, or Cox proportional hazards regression, as appropriate. Results Among 1,236 patients who had pulmonary resections, 937 received a combination of general anesthesia and TEA (TEA) and 299 received general anesthesia only (non-TEA). We successfully matched 311 TEA patients with 132 non-TEA patients. We did not find a significant association between TEA and postoperative atrial arrhythmia (odds ratio (95% CI) of 1.05 (0.50, 2.19), P = 0.9). TEA was not significantly associated with length of hospital stay or postoperative pulmonary complications (odds ratio (95% CI) of 0.71 (0.22, 2.29), P = 0.47). TEA patients experienced fewer postoperative cardiovascular complications; although the association was not statistically significant (odds ratio (95% CI) of 0.30 (0.06, 1.45), P = 0.06). Time-weighted average pain scores were similar in the two groups. Conclusion TEA was not associated with reduced occurrence of postoperative atrial arrhythmia. Although postoperative pulmonary complications were similar with and without TEA, TEA patients tended to experience fewer cardiovascular complications. Keywords Epidural anesthesia * Atrial arrhythmias * Pulmonary resection, Introduction Atrial arrhythmia is a common complication after noncardiac thoracic surgery [1, 2]. Although usually self-limited, the occurrence of atrial arrhythmia has been associated with increased costs, prolonged hospital stay, [...]

Purpose Continuous transversus abdominis plane (TAP) block using a catheter has proven its usefulness in reducing opioid requirements and pain scores after lower abdominal surgery. However, there are no reports of its successful use after renal transplant. We tested the hypothesis that continuous TAP block would retrospectively reduce opioid requirement, nausea score and hospital stay after renal transplant surgery. Methods In a retrospective study, we reviewed the data from 63 adult renal transplant recipients--31 with patient-controlled TAP analgesia with standing orders for intravenous as well as oral opioids as needed and 32 with intravenous patient-controlled analgesia. The TAP catheter was inserted preoperatively using an ultrasound-guided technique. Infusion of ropivacaine 0.2% at 8 ml basal, 12 ml bolus and a lockout interval of 60 min were maintained for 48 h postoperatively. The primary outcome was total morphine-equivalent dose during the 48-h postoperative period. Secondary outcomes were pain and nausea scores for the 48-h postoperative period. Results The mean 48-h postoperative morphine-equivalent doses [95% confidence interval] for patient-controlled intravenous analgesia and TAP catheter were 197 [111, 349] and 50 [28, 90], respectively, which were significantly different (P = 0.002). The mean 48-h average verbal response pain scores were 2.94 [2.39, 3.50] and 2.49 [1.93, 3.06], respectively, which were not significantly different (P = 0.26). The mean nausea scores were 0.66 [0.46, 0.87] and 0.60 [0.40, 0.81], respectively, which were not significantly different (P = 0.69). There was no difference regarding hospital stay. Conclusion The use of continuous TAP analgesia for postoperative analgesia after renal transplant was effective in reducing the morphine-equivalent requirements. Keywords Local anesthetic--ropivacaine * Opioid analgesics--morphine * Abdominal surgery * Kidney transplantation * TAP catheter * Nausea, Introduction Renal transplant (RT) is now considered the best therapeutic option for end-stage renal disease as it prolongs life as well as improving quality and quantity of life [1]. In [...]