Neuromuscular

Checking mask ventilation before neuromuscular block

The outdated and misguided notion of there being safety in checking mask ventilation before giving the muscle relaxant persists as shown in this Swedish survey.

“The most common reason for checking mask ventilation was “to gather information about the airway,” while the reason for not using was mostly “that muscle relaxation often improves mask ventilation.”

The latter has been shown to be the case. In any event the difficult airway is already lost after Propofol. Airway guidelines need to incorporate this knowledge in guidelines.

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Induction Technique Among Infants and Neonates Undergoing Pyloromyotomy

The decline is Succinylcholine use has been expedited by the arrival of Sugammadex. Succinylcholine is often still preferred where the risk of aspiration is deemed higher.

This study compared rapid sequence induction (RSI) with modified rapid sequence induction (mRSI) in infants.

The conclusion found mRSI acceptable practice: “In infants presenting for pyloromyotomy, anesthetic induction with mRSI compared with RSI was associated with significantly less hypoxemia without an observed increase in aspiration events. In addition, the need for multiple intubation attempts was a strong predictor of hypoxemia. The increased risk of hypoxemia associated with RSI and multiple intubation attempts was even more pronounced in neonatal patients.”

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Sugammadex and Postoperative Myasthenic Crisis

This was a database study with its inherent limitations but looked at adults with Myasthenia Gravis undergoing thymectomy and postoperative outcomes, specifically examining the use of Sugammadex.

They found that sugammadex was associated with reductions in postoperative myasthenic crisis and total hospitalization costs and length of stay, but no differences in the secondary outcome of postoperative pneumonia.

They advocate the routine use of Sugammadex in such patients.

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Early Neuromuscular Blockade in ARDS

The fashion that has returned for early neuromuscular block in ARDS was tested in this study.

“Among patients with moderate-to-severe ARDS who were treated with a strategy involving a high PEEP, there was no significant difference in mortality at 90 days between patients who received an early and continuous cisatracurium infusion and those who were treated with a usual-care approach with lighter sedation targets”.

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Deep Neuromuscular Block and Surgical Conditions

Two studies on the potential benefits of deeper neuromuscular block during laparoscopic surgery produce somewhat different results.

The first finds: Switching from moderate to deep block improves surgical conditions. Poor surgical conditions were associated with a higher incidence of surgical complications.

The second finds: Continuous rocuronium infusion did not improve surgical conditions when boluses of rocuronium were available on-demand. No major benefits in other outcomes were seen.

The debate continues…

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Fentanyl and Post-Op Respiratory Complications

There has been a decrease in intraoperative opioid use due to the twin concerns of opioid induced hyperalgesia and acute opioid tolerance especially with short acting agents. Opioid free anesthesia is common with various combinations of agents like Dexmedetomidine, Lidocaine, and Ketamine.

The pendulum sometimes swings too far, as is echoed by laws and restrictions on opioid prescription resulting in inappropriate sudden opioid discontinuation.

This analysis evaluated the association of intraoperative fentanyl dose and postoperative respiratory complications within 3 days after surgery (defined as reintubation, respiratory failure, pneumonia, pulmonary edema, or atelectasis).

Intraoperative low-dose fentanyl (about 60–120 μg for a 70 kg patient) was associated with lower risk of postoperative respiratory complications compared with both no fentanyl and high-dose fentanyl. Beneficial effects of low-dose fentanyl were augmented in thoracic surgery, and with high dose inhalational anaesthetics and neuromuscular blocking agents. A randomized controlled study might clarify the significance of these findings.

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Prevention & Management of Accidental Awareness

Awareness under general anesthesia is still encountered in situations not that rare. The Royal College of Anaesthetists and Association of Anaesthetists have issued this guidance on the topic, incorporating NAP5 evidence.

Discussion on approach to consent, anesthesia management, monitoring, and how efforts to minimize awareness takes place in the document. Special emphasis on the prudent use of neuromuscular blocking agents occurs.

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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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