Efficacy of superior laryngeal nerve block in reducing retching during transesophageal echocardiography: a randomized...

Transesophageal echocardiography (TEE) is a vital diagnostic procedure, but retching can be provoked during TEE examination, potentially resulting in severe complications. The internal branch of the superior laryngeal nerve (iSLN) block has potential to attenuate supraglottic discomfort and inhibit the retching caused by foreign body stimulation in the larynx and glottis. Therefore, the objective of this study was to evaluate the efficacy of iSLN block in mitigating complications associated with TEE examinations and improving patient comfort.

One hundred forty-eight patients scheduled for TEE were randomized to either Group C: tetracaine syrup (1%) for oropharyngeal surface anesthesia (n = 74) or Group S: tetracaine syrup (1%) for oropharyngeal surface anesthesia and followed by bilateral iSLN block (lidocaine, 2%, 2 ml for each side) (n = 74). Under ultrasound guidance, the iSLN was identified and exposed below the thyrohyoid membrane. The primary outcome was the incidence of the retching. Secondary outcomes included the incidence of oropharyngeal mucosal bleeding, rapid TEE probe insertion rate, patient comfort, and hemodynamic response.

The incidence of retching was significantly lower in Group S compared with Group C (12.16% vs. 39.19%, P < 0.001). Group S also showed significantly lower incidences of oropharyngeal mucosal bleeding (8.11% vs. 27.02%, P < 0.001) and higher rapid probe insertion rate (93.24% vs. 82.43%, P = 0.044), as well as improved patient comfort scores (P < 0.001). The absolute changes in mean arterial pressure during TEE examination were smaller in Group S (P = 0.001). Multivariate analysis identified low body mass index and high Mallampati classification as independent risk factors for retching.

Bilateral iSLN block significantly reduces the incidence of retching and oropharyngeal mucosal bleeding, while improving patient comfort, increasing the rapid TEE probe insertion rate, and stabilizing MAP during TEE examination. This technique can significantly improve patient experience and safety during TEE procedures.

The study was registered at Chictr.org.cn with the number ChiCTR2300076359 on 07/10/2023.