Articles: tracheal-tube.
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Paediatric anaesthesia · Nov 2023
Review Meta AnalysisSupraglottic airway device versus tracheal tube for pediatric laparoscopic surgery-A systematic review and meta-analysis SGA for pediatric laparoscopy.
Conventionally, tracheal tubes have been used for general anesthesia in pediatric laparoscopic surgeries. Recently, supraglottic devices are being used for the same. The performance of supraglottic devices versus tracheal tubes in children undergoing laparoscopic surgery is uncertain. ⋯ There is low quality evidence to suggest that for pediatric laparoscopic surgeries of short duration, supraglottic devices could provide comparable intraoperative ventilation in terms of peak airway pressures and end tidal carbon dioxide, with lower odds of postoperative sore throat and faster recovery time when compared to tracheal tubes.
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In this review, Karmali & Rose challenge the dogma surrounding endotracheal tube sizing for adult anaesthesia, traditionally sizing based on sex.
What did they cover?
They explored both the functional consequences (good and bad) of ETT size, as well as airway trauma.
Noting that an ETT ≥ 6.0mm ID will accomodate most intraluminal devices, and in fact at these smaller sizes fibreoptic intubation or passage through an LMA is easier, however smaller tubes are more readily obstructed and deformed.
Ventilation through smaller ETTs
While smaller tubes may require slightly higher inspiratory pressures, these are generally not clinically significant with modern ventilators, and importantly do not translate to higher intra-tracheal or alveolar pressures experienced by the patient.
Similarly, expiratory gas flow is not significantly effected by a small ETT (6.0 mm) for most patients even at high minute ventilations (although use cautiously in patients with chronic airway limitation). Significant gas trapping at normal MV will start to occur with ETT < 5.0 mm.
Size and airway trauma?
While the internal diameter (ID) is important for anaesthesia conduct, it is the external diameter that matters for airway trauma (a standard 8.0 mm ID ETT has a 10.5 mm ED!).
They note while there is wide individual variation in tracheal dimensions, the trachea is narrowest at the subglottis – and thus adequate visualisation of the glottis at time of intubation is an incomplete indicator of the tube size suitability for the subglottis.
Not only do some adult women have an airway size at the lower-limit of acceptability for traditional 7.0-8.0 mm ETTs, but there is also correlation between ETT size and airway trauma, hoarseness and sore throat. A large ETT can result in mucosal ischaemia and ulceration after as little as 2 hours.
They conclude...
"Instead of opting for ‘the largest tube that the larynx will comfortably accommodate’, we perhaps should consider using the smallest tube which permits the safe conduct of anaesthesia."
For routine anaesthesia of ASA 1 & 2 patients, an ETT sized 6.0-7.0 mm is probably the best balance between ventilation needs and airway trauma.
Be smart
But remember, many of the concerns for tracheal tube trauma are based upon critical care experience, not anaesthesia. While a smaller tube is very likely beneficial for most elective adult patients, most benefit will simply be reduction in post-operative sore throat and hoarseness.
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Review Meta Analysis
Efficacy of topical agents for prevention of postoperative sore throat after single lumen tracheal intubation: a Bayesian network meta-analysis.
The optimal choice of prophylactic drugs to decrease postoperative sore throat is unclear. The objective of this network meta-analysis (NMA) was to compare and rank 11 topical agents used to prevent postoperative sore throat. ⋯ Topical application of magnesium followed by liquorice and corticosteroids most effectively prevented postoperative sore throat 24 hr after endotracheal intubation.
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Review Meta Analysis
Intravenous lidocaine to prevent postoperative airway complications in adults: a systematic review and meta-analysis.
Intravenous lidocaine/lignocaine reduces post-extubation cough and sore throat.
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The optimal ventilation rate during cardiopulmonary resuscitation (CPR) with a tracheal tube is unknown. We evaluated whether in adults with cardiac arrest and a secure airway (tracheal tube), a ventilation rate of 10min-1, compared to any other rate during CPR, improves outcomes. ⋯ A ventilation rate recommendation of 10 min-1 during adult CPR with a tracheal tube and no pauses for chest compression is a very weak recommendation based on very low quality evidence.