Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2020
Meta AnalysisEfficacy of Intrathecal Fentanyl for Cesarean Delivery: A Systematic Review and Meta-analysis of Randomized Controlled Trials With Trial Sequential Analysis.
For cesarean section under spinal, addition of intrathecal fentanyl to bupivacaine, with or without morphine, may improve intraop & immediate postop analgesia, but increases pruritis incidence.
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Anesthesia and analgesia · Jan 2020
Comparative Study Observational StudyMonitoring Depth of Hypnosis: Mid-Latency Auditory Evoked Potentials Derived aepEX in Children Receiving Desflurane-Remifentanil Anesthesia.
The aepEXplus monitoring system, which uses mid-latency auditory evoked potentials to measure depth of hypnosis, was evaluated in pediatric patients receiving desflurane-remifentanil anesthesia. ⋯ The aepEX can reliably differentiate between a conscious and an unconscious state in pediatric patients receiving desflurane-remifentanil anesthesia.
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Anesthesia and analgesia · Jan 2020
Comparative StudyPerformance of Air Seal of Flexible Reinforced Laryngeal Mask Airway in Thyroid Surgery Compared With Endotracheal Tube: A Randomized Controlled Trial.
Why is this important?
Indications for the use of laryngeal mask airways (LMAs) increasingly challenge our airway choice for surgical procedures where endotracheal intubation has been the norm. Thyroid surgery, with its limited anaesthetic access to the airway and potential for airway obstruction, has not typically been a first choice for LMA use.
Proponents point to avoiding muscle relaxants and reducing throat pain and laryngeal trauma as the main benefits.
What did they do?
Gong and team randomised 138 ASA 1 & 2 adults to either flexible (reinforced) LMA or intubation with an ETT (7.0 or 7.5 mm). Notably any patients with surgical complexity or BMI > 30 kg/m2 were excluded. The study was single-blinded.
Concluding
The researchers reported the upper 95%-CI for estimated mean difference in peak airway pressure as +0.96 cmH2O, and for endtidal-CO2 +1.99 mmHg – neither of which are clinically significant.
They concluded that flexible-LMA was non-inferior to ETT in terms of PAP and ET-CO2.
Hang on...
The relevance of this study to most thyroid surgical patients is however limited at best. Not only were common groups of patients excluded (ie. BMI > 30) but one of the major arguments for LMA use (avoiding muscle relaxants) was irrelevant: all patients were paralysed with rocuronium.
Further, in 7% of the LMA cases severe air-leak occured and the surgical team were asked to cease or reduce tracheal traction.
Be smart
Although the journal editors conclude in their Key Points that "FLMA is a safe alternative for experienced anesthesiologists in thyroid surgery" this seems quite a stretch given that this small study was neither powered for safety and only investigated airway ventilation performance as a narrow surrogate for acceptability.
Additionally the authors themselves highlight very real surgical concerns that LMA use can distort pharyngeal anatomy with serious consequences.
Not dissimilar to arguments for LMA use in GA caesarean section, the use of an LMA for thyroid surgery edges toward 'just because we can, does not mean we should'.
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Anesthesia and analgesia · Jan 2020
Comparative Study Observational StudyVentilator Mode Does Not Influence Blood Loss or Transfusion Requirements During Major Spine Surgery: A Retrospective Study.
Blood loss during adult spinal deformity surgery is multifactorial. Anesthetic-related factors, such as mode of mechanical ventilation, may contribute to intraoperative blood loss. The aim of this study was to determine the influence of ventilator mode and ventilator parameters on intraoperative blood loss and transfusion requirements in patients undergoing prone position spine surgery. ⋯ In prone position spine surgery, neither mode of mechanical ventilation nor airway pressure is associated with intraoperative blood loss or need for allogeneic transfusion. Use of modern ventilation strategies using lung protective techniques may mitigate differences in blood loss previously observed between PCV and VCV modes.