Role of ultrasonography in an impalpable tissue larynx model during a simulated front-of-neck access scenario: a randomized simulation study.

PURPOSE: A large vertical incision is recommended when performing front-of-neck access in patients with impalpable neck landmarks during a cannot intubate-cannot oxygenate (CICO) scenario. We investigated the impact of ultrasonography on vertical incision size of a front-of-neck access on an ultrasound-compatible impalpable porcine larynx model. METHODS: Emergency medicine and anesthesia trainees were randomized to the Ultrasound (US, n = 21) and Non-Ultrasound (NUS, n = 21) groups. Within 1 week after a teaching session on airway ultrasound and Scalpel-Bougie-Tube (SBT) technique, participants were instructed to perform cricothyroidotomy on the model during a simulated cannot intubate-cannot oxygenate scenario. The primary outcome was a vertical size incision. Secondary outcomes were procedural completion time, horizontal size incision, tissue injury severity, and correct tube placement. RESULTS: The ultrasound group performed a significantly smaller vertical incision [median (IQR), 35.0 (15, 40) vs 65.0 (52, 100) mm (95% CI) - 30.0 (- 55.1, - 4.9), p = 0.02] and took longer total time to complete the procedure [median (IQR), 200.5 (126, 267) vs 93.5 (71.0, 167.5) secs (95% CI) 91.0 (3.73, 178.3), p = 0.04]. Tissue injury severity and correct tube placement were similar between groups. CONCLUSIONS: Ultrasound-guided identification of the cricothyroid membrane significantly reduced the recommended vertical incision size with similar success rates. However, there was an increased time when performing a Scalpel-Bougie-Tube cricothyroidotomy on an impalpable porcine larynx model by physicians in training. Ultrasonography should not be used in an emergency scenario of airway rescue. Its potential use to pre-mark the cricothyroid membrane should be considered in difficult airway management of impalpable neck.

RéSUMé: OBJECTIF: Il est recommandé de pratiquer une grande incision verticale lors de l'accès à l'avant du cou chez les patients dont les repères du cou sont impalpables, dans le cadre d'un scénario d'intubation impossible à oxygéner (CICO). Nous avons étudié l'impact de l'échographie sur la taille de l'incision verticale d'un accès à la face avant du cou sur un modèle de larynx porcin impalpable compatible avec l'échographie. MéTHODES: Des stagiaires en médecine d'urgence et en anesthésie ont été répartis de manière aléatoire entre les groupes "échographie" (US, n = 21) et "non-échographie" (NUS, n = 21). Une semaine après une session d'enseignement sur l'échographie des voies aériennes et la technique Scalpel-Bougie-Tube (SBT), les participants ont reçu l'instruction de réaliser une cricothyroïdotomie sur le modèle lors d'un scénario simulé d'impossibilité d'intubation et d'oxygénation. Le résultat primaire était une incision de taille verticale. Les résultats secondaires étaient le temps de réalisation de la procédure, la taille horizontale de l'incision, la gravité de la lésion tissulaire et le placement correct du tube. RéSULTATS: Le groupe échographie a réalisé une incision verticale significativement plus petite [médiane (IQR), 35,0 (15,40) vs 65,0 (52,100) mm (IC à 95 %) -30,0 (-55,1, -4,9), p = 0,02] et a pris un temps total plus long pour terminer la procédure [médiane (IQR), 200,5 (126, 267) vs 93,5 (71,0, 167,5) secondes (IC à 95 %) 91,0 (3,73, 178,3), p = 0,04]. La gravité des lésions tissulaires et le placement correct du tube étaient similaires entre les groupes. CONCLUSIONS: L'identification échoguidée de la membrane cricothyroïdienne a réduit de manière significative la taille de l'incision verticale recommandée avec des taux de réussite similaires. Cependant, il y avait une augmentation du temps lors de la réalisation d'une cricothyroïdotomie Scalpel-Bougie-Tube sur un modèle de larynx porcin impalpable par des médecins en formation. L'échographie ne doit pas être utilisée dans un scénario d'urgence de sauvetage des voies respiratoires. Son utilisation potentielle pour pré-marquer la membrane cricothyroïdienne devrait être envisagée dans la gestion des voies aériennes difficiles du cou impalpable.

Complications of cricothyroidotomy versus tracheostomy in emergency surgical airway management: a systematic review.

BACKGROUND: Airway guidelines recommend an emergency surgical airway as a potential life-saving treatment in a "Can't Intubate, Can't Oxygenate" (CICO) situation. Surgical airways can be achieved either through a cricothyroidotomy or tracheostomy. The current literature has limited data regarding complications of cricothyroidotomy and tracheostomy in an emergency situation. The objective of this systematic review is to analyze complications following cricothyroidotomy and tracheostomy in airway emergencies. METHODS: This synthesis of literature was exempt from ethics approval. Eight databases were searched from inception to October 2018, using a comprehensive search strategy. Studies were included if they were randomized controlled trials or observational studies reporting complications following emergency surgical airway. Complications were classified as minor (evolving to spontaneous remission or not requiring intervention or not persisting chronically), major (requiring intervention or persisting chronically), early (from the start of the procedure up to 7 days) and late (beyond 7 days of the procedure). RESULTS: We retrieved 2659 references from our search criteria. Following the removal of duplicates, title and abstract review, 33 articles were selected for full-text reading. Twenty-one articles were finally included in the systematic review. We found no differences in minor, major or early complications between the two techniques. However, late complications were significantly more frequent in the tracheostomy group [OR (95% CI) 0.21 (0.20-0.22), p < 0.0001]. CONCLUSIONS: Our results demonstrate that cricothyroidotomies performed in emergent situations resulted in fewer late complications than tracheostomies. This finding supports the recommendations from the latest Difficult Airway Society (DAS) guidelines regarding using cricothyroidotomy as the technique of choice for emergency surgical airway. However, emergency cricothyroidotomies should be converted to tracheostomies in a timely fashion as there is insufficient evidence to suggest that emergency cricothyrotomies are long term airways.