Ultrasound-guided erector spinae plane block versus thoracic epidural block for postoperative analgesia in pediatric Nuss surgery: a randomized noninferiority trial.

PURPOSE: Thoracic epidural anesthesia (TEA) is often used for analgesia after thoracic surgery. Erector spinae plane block (ESPB) has been proposed to provide adequate analgesia. We hypothesized that ESPB would be noninferior to TEA as a part of multimodal analgesia in pediatric patients undergoing the Nuss procedure. METHODS: Patients aged 7-18 years and scheduled for the Nuss procedure were randomly allocated to receive bilateral single-shot ESPB or TEA and a multimodal analgesic regimen including parent-controlled intravenous analgesia (PCIA). At 6 h, 12 h, 18 h, and 24 h postoperatively, pain was evaluated using the numeric rating scale (NRS) and opioid consumption was assessed by counting the number of PCIA boluses. The joint primary outcomes were the average pain score and opioid consumption at 24 h after surgery. The secondary outcomes were the NRS scores and the number of opioid boluses administered at different postoperative time points, adverse events, and recovery quality. RESULTS: Three hundred patients underwent randomization, and 286 received ESPB (147 patients) or TEA (139 patients). At 24 h postoperatively, ESPB was noninferior to TEA in terms of the average NRS score (mean difference, - 0.1, 95% confidence interval [CI], - 0.3-0.1, margin = 1, P for noninferiority < 0.001) and the number of opioid boluses administered (mean difference, - 1.1, 95% CI, - 2.8-0.6, margin = 7, P for noninferiority < 0.001). Adverse events and patient recovery were comparable between groups. CONCLUSIONS: The results demonstrate that combined with a multimodal analgesia, ESPB provides noninferior analgesia compared to TEA with respect to pain score and opioid consumption among pediatric patients undergoing the Nuss procedure.

Diffusion of polymer-grafted nanoparticles with dynamical fluctuations in unentangled polymer melts.

The dynamics of polymer-grafted nanoparticles (PGNPs) in melts of unentangled linear chains were investigated by means of coarse-grained molecular dynamics simulations. The results demonstrated that the graft monomers closer to the particle surface relax more slowly than those farther away due to the constraint of the grafted surface and the confinement of the neighboring chains. Such heterogeneous relaxations of the surrounding environment would perturb the particle motion, making them fluctuating around their centers before they can diffuse through the melt. During such intermediate-time stage, the dynamics is subdiffusive while the distribution of particle displacements is Gaussian, which can be described by the popular fractional Brownian motion model. For the long-time Fickian diffusion, we found that the diffusivity D decreases with increasing grafting density Σg, grafted chain length Ng, and matrix chain length Nm. This is due to the fact that the diffusivity is controlled by the viscous drag of an effective core, consisting of the NP and the non-draining layer of graft segments, and that of the free-draining graft layer outside the "core". With increasing Σg, the PGNPs become harder with greater effective size and thinner free draining layer, resulting in a reduction in D. At extremely high Σg, the diffusivity can even be estimated by the diameter-renormalized Stokes-Einstein (SE) relation. With increasing Ng, both the effective core size and the thickness of the free-draining layer increase, leading to a reduction in diffusivity by D ∼ N-γg with 0.5 < γ < 1. Increasing Nm would lead to the enlargement of the effective core size but meanwhile result in the reduction of the free-draining layer thickness due to autophobic dewetting. The counteraction between these two opposite effects leads to only a slight reduction in the diffusivity, significantly different from the typical SE behavior where D ∼ Nm-1. These findings bear significance in unraveling the fundamental physics of the anomalous dynamics of PGNPs in various polymers, including biological and synthetic.

The Effect of Ultrasound-Guided Erector Spinae Plane Block versus Thoracic Epidural Block on Postoperative Analgesia After Nuss Surgery in Paediatric Patients: Study Protocol of a Randomized Non-Inferiority Design Trial.

PURPOSE: The Nuss procedure is a recognized treatment for adolescent pectus excavatum that results in severe postoperative pain. Erector spinae plane block (ESPB) is a novel technique that provides postoperative analgesia and reduces opioid consumption. Our aim is to explore whether ESPB produces analgesia similar to thoracic epidural anaesthesia (TEA) in paediatric patients undergoing Nuss procedure. STUDY DESIGN AND METHODS: This randomized, controlled, non-inferiority trial will enrol 300 paediatric patients undergoing Nuss surgery. Participants will be randomly assigned 1:1 to receive ESPB or TEA preoperatively. The primary, joint endpoint is the average numeric rating scale (NRS) score and cumulative sufentanil consumption. The secondary endpoints are pain scores and sufentanil consumption at different time points after surgery, analgesia-related side effects, and other postoperative complications. Data will be analysed by the intention-to-treat principle. DISCUSSION: This study investigates the effect of ESPB on postoperative opioid consumption and pain scores and intend to provide a new strategy of analgesia management for Nuss procedure in paediatric patients.