Neuromuscular

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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Perioperative Peripheral Nerve Injury After General Anesthesia

A review article discusses the incidence, mechanisms, diagnosis and prevention of peripheral nerve injuries during general anesthesia. It is an area still in evolution, as it is found that anesthesia care is appropriate in 90% of cases. Concepts such as ischemia, inflammation, “double crush”, mechanical factors are discussed as well as evoked potential monitoring like SSEP, nerve conduction studies and EMG.

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Intubation in OR vs ICU

A Spanish study compares OR vs ICU intubation by direct laryngoscopy. Everything was somewhat worse in  the ICU: worse view, lower first attempt success, higher rate of difficult intubation and use of airway adjuncts,  and higher complication rate. They suggest that patient and environmental factors may be of more importance than the operator (even previously known easy intubations were more difficult in ICU). Despite all that, their success rate was better than other studies, which they attribute to high use of neuromuscular blocking agents, an increasingly recommended practice. Videolaryngoscopy has met with better success in many but not all studies.

At the least, greater preparation, optimized positioning and airway equipment,  and trained assistance should be available for non-OR intubation

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Further NAP6 Allergy & Anesthesia Insights

Teicoplanin over 16 tines culprit antibiotic in allergic reaction – twice other antibiotics. It seems to be a UK thing in terms of practice.

Test doses don’t serve any real purpose.

Since most anaphylaxis occurs within 5-10 mins a suggestion is to administer before anesthesia induction.

B-Blockers and ACEIs as well as older sicker patients and those with coronary artery disease have more hypotension and do worse.

Obese patients figured highly in mortality cases.

Hypotension is the presenting sign in half. Most severe cases may not show skin rash. Bronchospasm more an initial feature of Succinylcholine, which is also responsible for twice the anaphylaxis rate of non-depolarizing agents. Rocuronium leads the latter pack, followed by Atracurium and Mivacurium. No cases with Vecuronium or Cisatracurium.

There is a potential and debated relationship between Rocuronium allergy and Pholcodine, an opioid cough suppressant especially used in Australia which could sensitize subjects.

Chlorhexidine identified as responsible agent in 9%, often presenting with hypotension that is delayed and missed as diagnosis.

Fluid and epinephrine are the go to treatments not steroids and antihistamines which only play a corollary role. Sugammadex is not at this point an evidence based treatment for Rocuronium allergy. CPR was not started in many cases when it should have been.

Patent Blue dye (used in sentinel node locating in breast surgery) also a significant allergy culprit.

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