Airway

OSA Screening in Pregnant Obese

Pregnant patients 24-35 weeks with BMI > 40 were given Obstructive Sleep Apnea (OSA) screening questionnaires (Berlin, American Society of Anesthesiologists checklist, and STOP-BANG), and the Epworth sleepiness scale. They underwent overnight sleep apnea testing; 24% had OSA.

“Established OSA screening tools performed very poorly to screen for OSA in this cohort. Age, BMI, neck circumference, frequent witnessed apneas and highly likely to fall asleep while driving were most strongly associated with OSA status in this cohort.”

OSA screening tools may need to be refined in this population.

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Laryngeal Tube and Cardiac Arrest Outcome

A strategy of initial laryngeal tube insertion, compared with endotracheal intubation, was associated with greater likelihood of 72-hour survival after out of hospital cardiac arrest.

There were small differences in secondary outcomes like favourable neurological status. Airway success rates were far higher in the laryngeal tube group and this makes it difficult to compare directly as intubation successes were so low here, about 50%, quite concerning

At least once again, supraglottic airways seem appropriate as a choice of initial airway management.

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Videolaryngoscopy vs. fibreoptic bronchoscopy for awake tracheal intubation

The time honoured use of fibreoptic awake intubation as the gold standard for the difficult airway comes into question in this review and meta-analysis. The results are that videolaryngoscopy for awake tracheal intubation is associated with a shorter intubation time. It also seems to have a success rate and safety profile comparable to fibreoptic bronchoscopy.

Nuances are hidden here – if insufficient mouth opening is present, fibreoptic may still be the choice, as it may be also with soiled or bloody airways. The key component is adequate airway topical anesthesia and varying recipes exist, and improper topicalization is still the main problem. Also sedation regimes vary – most commonly Propofol and/or Remifentanil, or Dexmedetomidine. The type of videolaryngoscope blade also has an impact, with highly angulated blades like the the Glidescope being favoured. Lastly a practice combining a videolaryngoscopic view with flexible fibreoptic intubation can be helpful in easily passing a tracheal tube.

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Intubation in ICU vs OR

The recurring line in studies such as this is that intubations outside the OR are always more difficult. The comparison was direct laryngoscopy in both groups. Most but not all studies have shown videolaryngoscopy to be better. The increasing use of neuromuscular blocking agents is now encouraged to improve first attempt success. Numerous other resource, staff and equipment issues probably come into play outside the OR, but it is incumbent on Anesthesiology to advocate for the most optimal setup and equipment outside their natural OR habitat!

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Cervical Spine Injury Intubation

The type of airway management for unstable cervical spine injury is described in this review from a Level I trauma centre. A dramatic change has occurrred from the traditional recommendation of flexible fibreoptic bronchoscopic (FOB) intubation. Videolaryngoscopy (VL) was used in about 50%, asleep FOB was performed alone (30.6%) or in conjunction with VL (13.5%). Awake FOB was rarely performed (2.3%), as was direct laryngoscopy (2.8%). All techniques were associated with high first-attempt success rates, and no cases of neurological injury attributable to airway management technique were identified.

While experience with videolaryngoscopy is becoming widespread, there is also a need to maintain FOB skills, but VL (even awake) is now clearly an accepted go-to technique.

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LMA-S vs. i-Gel in Elderly

In paralyzed elderly patients both the LMA-S and i-gel were used successfully and safely. However, the i-gel demonstrated better airway sealing than the LMA-S at insertion and during maintenance of anaesthesia. Less manipulation at insertion and superior fiberoptic laryngoscopy grades were observed in the i-Gel group, and inspiratory pressures lower with higher leak pressures. The I-Gel’s simplicity without the need for cuff inflation make it an attractive option in ER settings also for the ‘occasional anesthesiologist’!

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Remifentanil with Desflurane for LMA GA

While Sevoflurane is the standard agent for a non-irritating inhalational and spontaneously breathing anesthetic, the irritating effects of Desflurane  may be mitigated by the use of a Remifentanil infusion. This study showed that in the presence of a continuous infusion of remifentanil, desflurane is superior in terms of faster emergence and is similar in terms of intra-operative cough to sevoflurane or propofol infusion. Recovery time differences were of marginal clinical significance (2 minutes) but more predictable and less variable than other agents.

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Obstetric Failed Intubation

A literature review since 1970 of failed obstetric intubation at Cesarean delivery under general anesthesia reveals some themes.  Some salient features that emerged were the increasing tendency to continue GA usually with supraglottic airways, especially second generation devices like the ProSeal LMA.

The conflicting priorities of urgency, safety, maternal and fetal wellbeing make the decision on how to proceed difficult. Front of neck airway scenarios were sparse, but they are often done too late. There is surprisingly no data on videolaryngoscopy use in this review.

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