The influence of lymphoid reconstitution kinetics on clinical outcomes in allogeneic stem cell transplantation.

Lymphoid recovery following myeloablative stem cell transplantation (SCT) displays a logistic pattern of exponential growth followed by a plateau. Within this logistic framework, lymphoid recovery is characterized by the parameters R (slope of ascent), a (time of maximal rate of ascent) and K (plateau), the 'steady-state' lymphocyte count. A retrospective analysis of allogeneic SCT performed from 2008 to 2013 was undertaken to compare lymphoid recovery and clinical outcomes in 131 patients with acute myelogenous leukemia, acute lymphocytic leukemia, and myelodysplastic syndromes. Using Prism software, a logistic curve was successfully fit to the absolute lymphocyte count recovery in all patients. Patients were classified according to the magnitude and rate of lymphoid recovery; pattern A achieved an absolute lymphocyte counts (ALC) of >1000/µL by day 45, pattern B an ALC 500 < x < 1000/µL, and pattern C an ALC <500/µL. Pattern A was characterized by a higher mean K (p < .0001) compared with patterns B and C. Patients with patterns B and C were more likely to have mixed T cell chimerism at 90 d following SCT (p = .01). There was a trend towards improved survival (and relapse-free survival) in those with pattern A and B at 1 year compared to pattern C (p = .073). There was no difference in cGVHD (p = .42) or relapse (p = .45) between pattern types. Cytomegalovirus (CMV), aGVHD, and all relapse were heralded by deviation from logistic behavior. Pattern C patients were more likely to require donor lymphocyte infusion (DLI) (p = .017). Weaning of tacrolimus post-transplant was associated with a second, separate logistic expansion in some patients. This study demonstrated that lymphoid reconstitution follows a prototypical logistic recovery and that pattern observed correlates with T cell chimerism and need for DLI, and may influence survival.

Continuous versus single shot brachial plexus block and their relationship to discharge barriers and length of stay.

BACKGROUND: Brachial plexus block has been associated with improved pain control and decreased length of stay in patients undergoing upper extremity arthroplasty. Continuous delivery is associated with a shorter length of stay; however, comparisons to single-shot delivery in this setting are scarce. As the paradigm shifts to outpatient arthroplasty in the era of bundled payments, there exists a strong impetus to identify the most effective mode of analgesia associated with the least risk to patients. METHODS: This is a retrospective review of 697 patients undergoing upper extremity arthroplasty comparing the rate of complications and incidence of potential barriers to discharge and length of stay of patients receiving continuous vs. single-shot perineural brachial plexus block. RESULTS: No difference was observed in the complication rate between indwelling (n = 63 [12%]) and single-shot groups (n = 30 [17%]; P = .137). The majority of complications were pulmonary, 72% attributable to oxygen desaturation. The indwelling catheter group had 1.61 times higher odds (95% confidence interval, 1.07-2.42; P = .023) of exhibiting any potential barrier to discharge and exhibited a longer length of stay (P = .002). CONCLUSION: There was no demonstrated disparity in the rate of complications associated with single-shot vs. continuous brachial plexus block. However, the continuous indwelling catheter was associated with an increased incidence of potential barriers to discharge and an increased length of stay compared with patients receiving single-shot regional anesthesia.