Cervical spine immobilization does not interfere with nasotracheal intubation performed using GlideScope videolaryngoscopy: a randomized equivalence trial

Abstract

GlideScope-assisted nasotracheal intubation (NTI) has been proposed as an alternative to difficult orotracheal intubation for critical patients or those under cervical immobilization. We evaluated the difficulty of performing NTI using GlideScope under cervical orthosis. A total of 170 patients scheduled for elective cervical spinal surgery that required NTI were randomized to receive cervical immobilization using a cervical collar (collar group) or no cervical immobilization at all (control group) before anesthetic induction (group assignment at 1:1 ratio). All NTI during anesthetic induction were performed using the GlideScope. The primary outcome was time to intubation. The secondary outcomes were ease of intubation, including the necessity of auxiliary manipulations to assist intubation, and the nasotracheal intubation difficulty scale (nasoIDS). An exploratory analysis identified morphometric parameters as predictors of time to intubation, the necessity of auxiliary manipulations, and a nasoIDS score ≥ 4. For time to intubation, the mean difference (collar group—control) was − 4.19 s, with a 95% confidence interval (CI) of − 13.9 to 5.52 that lay within our defined equivalence margin of 16 s. Multivariate regressions precluded the association of cervical immobilization with a necessity for auxiliary manipulations (adjusted odds ratio [aOR] 0.53, 95% CI [0.26–1.09], P = 0.083) and a nasoIDS ≥ 4 (aOR 0.94 [0.84–1.05], P = 0.280). Among all morphometric parameters, the upper lip bite test class was predictive of a longer time to intubation (all analyses relative to class 1, 14 s longer for class 2, P = 0.032; 24 s longer for class 3, P = 0.070), increased necessity for auxiliary manipulation (aOR 2.29 [1.06–4.94], P = 0.036 for class 2; aOR 6.12 [1.04–39.94], P = 0.045 for class 3), and nasoIDS ≥ 4 (aOR 1.46 [1.14–1.89], P = 0.003 for class 3).The present study demonstrated that GlideScope achieved NTI in patients with or without cervical immobilization equivalently with respect to intubation time and ease.

A Paradigm Shift of Airway Management: The Role of Video-Assisted Intubating Stylet Technique

“…Among all the airway tools, VL has drawn the most attention as a useful tool for restricted C-spine motion. This technique has been tested in patients with a simulated restricted C-spine condition (with manual in-line stabilization or rigid cervical collar) [44, [134][135][136][137][138][139][140][141][142][143][144][145], in real patients undergoing C-spine surgeries [146,147], and in mannequin simulation model [148,149]. Recently, VS has also been tested in patients with simulated restricted Cspine motion [31, 78, 80, 81, 84, 150, 151].…”

The Use of the Shikani Video-Assisted Intubating Stylet Technique in Patients with Restricted Neck Mobility

“…Various VL products have been compared in such restricted C-spine motion scenario, evaluating success rate, glottis visualization, intubation time, and complications [ 9 ]. VL was also found to be advantageous in facilitating nasotracheal intubation in patients with simulated C-spine injuries [ 51 , 52 ], and VL produced a better glottic visualization during intubation under general anesthesia with neuromuscular blockade and manual in-line stabilization. On the other hand, when dealing with a non-pathologic C-spine, the difference between the two as regards spine movement was not significant [ 53 ].…”

急速に進行した気道閉塞に対して予防的に気管挿管を行ったCOVID–19合併外傷性咽頭後間隙血腫症例(A case of traumatic retropharyngeal hematoma in a patient with COVID–19 who underwent prophylactic tracheal intubation for rapidly progressing airway obstruction)

“…本症例の事前の気道評価では，咽頭後間隙血腫と頸椎外傷以外に気道確保困難因子はなかった。MRI画像およびCT画像では，第1–3頸椎椎体前面に軟部組織の出血に起因すると思われる血腫が多く見られたが，声帯がある第5頸椎上縁前面付近は比較的スペースがあった。頸椎保護に関しても，ビデオ喉頭鏡を用いれば気管挿管困難リスクとはならないとする報告もあり 20)，血腫がさらに前方や下方に進展する前に，舌根–咽頭後壁間の狭窄を挿管チューブやエアウェイが通過できれば気管挿管やマスク換気は可能と考えられた。さらに呼吸不全は呈しておらず，十分な前酸素化が可能であったため，エアロゾルボックスを使用した気管挿管は可能であると判断した。本症例で初回挿管に失敗した場合は，マスク換気を試行し，マスク換気が可能であれば，気管支鏡を用いた挿管を予定した。マスク換気困難であれば，筋弛緩拮抗薬を使用し，自発呼吸を回復させることと，輪状甲状靱帯穿刺による外科的気道確保を併行して準備することとした。声門上器具の準備はしたが，血腫により挿入困難やフィッティング不良のため換気困難となる可能性が高いと考えられた。本症例の気管挿管が成功した要因としては，上述のように画像を基に詳細な気道評価をしたうえで，気道アプローチの戦略を立てることができたことが一つの要因と考えられる。また，挿管操作により血腫を破裂させる危険があると指摘する報告もある 21)が，筋弛緩薬を使用し不動化したことにより，愛護的な手技が可能となり血腫を破裂させなかったことも気管挿管成功の一助となったと考えられる。報告では，約15分間の気管挿管を試行したものの気道確保ができず，CVCIから心停止に至り，緊急気管切開による気道確保を行った症例 12)があるように，気道閉塞の状況や気道確保の内容によっては，気道閉塞から心停止に至りうる。したがって，気道評価のうえで，CVCIのリスクがより高いと判断する場合は，COVID–19を合併している場合でも，患者安全の観点からエアロゾル対策を行ったうえで，初回気道確保の選択として意識下気管挿管や気管切開を選択する必要があると考えられる。…”