Usefulness of intra-operative neuromuscular blockade monitoring and reversal agents for postoperative residual neuromuscular blockade: a retrospective observational study.

BACKGROUND: Complete avoidance of residual neuromuscular blockade (RNMB) during the postoperative period has not yet been achieved in current anesthesia practice. Evidently, compliance with NMB monitoring is persistently low, and the risk of RNMB during the perioperative period remains underestimated. To our knowledge, no publications have reported the incidence of RNMB in a university hospital where access to quantitative NMB monitoring and sugammadex is unlimited and where NMB management is not protocolised. The primary aim of this study was to estimate the incidence of RNMB in patients managed with or without sugammadex or neostigmine as antagonists and quantitative NMB monitoring in the operating room. The secondary aim was to explore the associations between RNMB and potentially related variables. METHODS: This retrospective observational cohort study was conducted at a tertiary referral university hospital in Buenos Aires, Argentina. Records created between June 2015 and December 2015 were reviewed. In total, 240 consecutive patients who had undergone elective surgical procedures requiring NMB were included. All patients were monitored via acceleromyography at the adductor pollicis muscle within 5 min of arrival in the postanaesthesia care unit (PACU). Scheduled recovery in the intensive care unit was the only exclusion criterion. RESULTS: RNMB was present in 1.6% patients who received intra-operative quantitative NMB monitoring and 32% patients whose NMB was not monitored (P <  0.01). Multivariable analysis revealed that the use of intra-operative quantitative NMB monitoring and sugammadex were associated with a lower incidence of RNMB, with calculated odds ratios of 0.04 (95% confidence interval [CI]: 0.005 to 0.401) and 0.18 (95% CI: 0.046 to 0.727), respectively. CONCLUSIONS: The results of the present study suggest that intra-operative quantitative NMB monitoring and use of sugammadex are associated with a decreased incidence of RNMB in the PACU, reinforcing the contention that the optimal strategy for RNMB avoidance is the use of quantitative NMB monitoring and eventual use of reversal agents, if needed, prior to emergence from anaesthesia.

Structure and mechanism of GumK, a membrane-associated glucuronosyltransferase.

Xanthomonas campestris GumK (beta-1,2-glucuronosyltransferase) is a 44-kDa membrane-associated protein that is involved in the biosynthesis of xanthan, an exopolysaccharide crucial for this bacterium's phytopathogenicity. Xanthan also has many important industrial applications. The GumK enzyme is the founding member of the glycosyltransferase family 70 of carbohydrate-active enzymes, which is composed of bacterial glycosyltransferases involved in exopolysaccharide synthesis. No x-ray structures have been reported for this family. To better understand the mechanism of action of the bacterial glycosyltransferases in this family, the x-ray crystal structure of apo-GumK was solved at 1.9 angstroms resolution. The enzyme has two well defined Rossmann domains with a catalytic cleft between them, which is a typical feature of the glycosyltransferase B superfamily. Additionally, the crystal structure of GumK complexed with UDP was solved at 2.28 angstroms resolution. We identified a number of catalytically important residues, including Asp157, which serves as the general base in the transfer reaction. Residues Met231, Met273, Glu272, Tyr292, Met306, Lys307, and Gln310 interact with UDP, and mutation of these residues affected protein activity both in vitro and in vivo. The biological and structural data reported here shed light on the molecular basis for donor and acceptor selectivity in this glycosyltransferase family. These results also provide a rationale to obtain new polysaccharides by varying residues in the conserved alpha/beta/alpha structural motif of GumK.