Neuromuscular

Rocuronium before Mask Ventilation

Another randomized study supports just giving the neuromuscular blocking agent before testing mask ventilation as it ultimately leads to better mask ventilation and earlier intubation.

This practice is in line with modern expert recommendations, despite running counter to previous teachings. The airway is already often lost with anesthesia induction before the relaxant and muscle relaxation aids in ventilation.

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Residual Neuromuscular Blockade

The incidence of residual neuromuscular blockade after anesthesia is, in short, too high and this retrospective study sought to establish its relationship to hospital costs. While there was not an independent association with hospital cost, there was a greater odds of ICU admission, along with a trend towards increased hospital length of stay.

The findings continue to support rigorous quantitative monitoring of neuromuscular function during anesthesia and adequate reversal to a minimum Train-of-Four of 0.9, and probably more optimally 1.

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Sugammadex in the Elderly

A study using low dose Sugammadex (0.4mg/kg) showed that recovery of train-of-four ratios was slower and recurarization was more common in the elderly after Rocuronium neuromuscular blockade. Renal dysfunction and obesity imposed a higher risk; even 4mg/kg may not suffice in some. The bottom line in all elderly patients is that neuromuscular monitoring is just as imperative with Sugammadex as other agents in ensuring adequate reversal.

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Sugammadex Effectiveness in Elderly

Sugammadex was tested tested in elderly patients for reversing deep Rocuronium induced neuromuscular block. Increasingly seen as s faster and more complete agent compared to Neostigmine, this study found that low (as well as common clinical doses) were not as fast or effective in the elderly, and residual blockade and recurarization were more common. Renal function and obesity were risk factors also. The study highlights the need again for universal neuromuscular monitoring in all patients, even when Sugammadex is used.

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Neostigmine-Induced Muscle Weakness

While an immense amount of literature on inadequate neuromuscular block reversal exists, this study shows that Neostigmine in the absence of any neuromuscular block can cause weakness itself, resembling a Phase 1 depolarizing block that may not be readily apparent by train-of-four stimulation.

The clinical scenario may be slightly different in the presence of some residual muscle paralysis but the study speaks to the need for universal (and better) neuromuscular monitors as always, especially if hours have elapsed since a muscle relaxant was given. It will be seized upon by Sugammadex enthusiasts who see this latter agent as a better and quicker reversing agent.

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TOFscan vs. TOF-Watch for Neuromuscular Recovery

This observational study tested a new neuromuscular monitor that extends acceleromyography to 3-dimensions unlike the 2-dimensional TOF-Watch. It also requires no calibration or normalization and setup is easier than the TOF-Watch. The authors conclude: “Good agreement between the TOF-Watch SX with calibration and preload application and the uncalibrated TOFscan was observed throughout all stages of neuromuscular recovery”.

Considering the alarming evidence of incomplete reversal after surgery, a simpler device is highly desirable and this study is encouraging.

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Neuromuscular Depth and Surgical Conditions

In an era where deep neuromuscular blockade is out of fashion, along with residual paralysis concerns, this study shows that in patients undergoing elective laparoscopic colorectal surgery, deep neuromuscular blockade was associated with better surgical conditions than moderate blockade, as measured by a reduction in the incidence of intra-abdominal pressure alarms (as well as surgical rating). The moderate group was reversed with Neostigmine and the deep group with Sugammadex 4mg/kg. The availability of Sugammadex certainly makes this a more feasible practice.

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