Modified anterior approach versus traditional posterior approach for ultrasound-guided superior laryngeal nerve block in awake endotracheal intubation: a randomized non-inferiority clinical trial

Abstract

Study objective

This study was undertaken to compare the effect of the modified ultrasound-guided anterior superior laryngeal nerve block (SLNB) with the traditional ultrasound-guided posterior SLNB in providing intubation conditions during awake tracheal intubation (ATI) in patients without difficult airway.

Design

Randomized, assessor-blind. Registration number: ChiCTR2200058086.

Setting

West China Hospital of Sichuan University, Chengdu, China.

Patients

104 patients aged 18–65 years, of American Society of Anesthesiologists status I-III, posted for elective general surgery with general endotracheal anesthesia.

Interventions

The patients were randomized into two groups (modified group, n = 52; traditional group, n = 52). Modified anterior SLNB or traditional posterior SLNB was performed under ultrasound guidance.

Measurements

The primary outcome was the proportion of acceptable intubation condition (AIC), which was analyzed in both per-protocol (PP) and intention-to-treat (ITT) populations. The prespecified non-inferiority margin was −4.8%. Secondary outcomes included intubation success rate on the first attempt, hemodynamic parameters during ATI, time taken for airway anesthesia and intubation, recall of intubation, patient perception of comfort, and incidence and severity of postoperative complications.

Main results

In the PP population, the proportion of AIC in the modified group was 49/49 (100%) and that in the traditional group was 49/49 (100%), absolute difference 0, lower limit of 1-sided 95% CI, −0.3%. In the ITT population, the primary outcomes in the modified and traditional group were 52/52 (100%) and 51/52 (98.1%), respectively, with an absolute difference of 1.9% and a lower limit of 1-sided 95% CI of −1.2%. The non-inferiority of modified ultrasound-guided anterior SLNB was confirmed in both populations.

Conclusions

Among adults without difficult airways during videolaryngoscope-assisted ATI, the modified ultrasound-guided anterior SLNB, compared to the traditional posterior approach, showed a statistically non-inferior effect in terms of providing AIC.

Keywords:

• Airway nerve block
• awake tracheal intubation
• superior laryngeal nerve block
• intubation conditions
• randomized controlled trial

Authors contributions

Qiyuan Huang conceptualization and design of the study; investigation; analyses and interpretation of the data; original draft preparation; final approval of the version to be published; and agreement to be accountable for all aspects of the work.

Yusi Hua design and methodology; manuscript review and editing; pilot study implementation; final approval of the version to be published; agreement to be accountable for all aspects of the work.

Ruihao Zhou original draft preparation, final approval of the version to be published, agreement to be accountable for all aspects of the work.

Guo Chen conceptualization, resources, supervision, manuscript review and editing, final approval of the version to be published, agreement to be accountable for all aspects of the work.

Tao Zhu conceptualization, supervision, manuscript review and editing, final approval of the version to be published, agreement to be accountable for all aspects of the work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data relevant to the study are included in the article or are uploaded as Supplementary Information. The data supporting the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [grant number 2018YFC2001800] to TZ and the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences [grant number 2019-I2M-5-011] to TZ.