The Cricothyroid versus Spray-As-You-Go Method for Topical Anesthesia during Flexible Bronchoscopy: The CRISP Randomized Clinical Trial

Abstract

<b><i>Background:</i></b> Comparative characteristics of the cricothyroid injection and spray-as-you-go methods for lidocaine administration during diagnostic flexible bronchoscopy are not clear. <b><i>Objectives:</i></b> Co-primary outcomes were comparison of cough count from bronchoscope introduction until reaching carina and operator-rated overall procedure satisfaction on a Visual Analogue Scale (VAS) between groups. Secondary outcomes were cumulative lidocaine dose, procedure duration, assistant-rated cough, willingness to return for repeat procedure, and procedural complications between groups. <b><i>Methods:</i></b> Consecutive subjects were randomized (1:1) to either the cricothyroid or the spray-as-you-go method for topical anesthesia to the vocal cords and trachea. All received nasal 2% lidocaine gel and pharyngeal 10% lidocaine spray. <b><i>Results:</i></b> A total of 500 subjects were randomized, and 495 subjects were analyzed (248 cricothyroid and 247 spray-as-you-go). Cough count until reaching carina (median [range]) was significantly lower (cricothyroid, 1 [0–10], and spray-as-you-go, 4 [0–30], <i>p</i> < 0.0001) and operator-rated overall procedure satisfaction, VAS (mean ± standard deviation) (cricothyroid, 7.86 ± 1.39 and spray-as-you-go, 6.86 ± 1.59, <i>p</i> < 0.0001) significantly greater in the cricothyroid group. Patient willingness to return for repeat procedure was greater (87.1 vs. 70.5%, <i>p</i> < 0.001)) and cumulative lidocaine dose significantly lower (305.08 ± 13.40 vs. 322.18 ± 10.67 mg, <i>p</i> < 0.001) in the cricothyroid group. Minor complications occurred in 6 patients in the cricothyroid group and 9 patients in the spray-as-you-go group. <b><i>Conclusion:</i></b> Cricothyroid lidocaine administration is associated with less cough and superior operator-rated procedure satisfaction during bronchoscopy at a lower cumulative lidocaine dose.

Guidelines for diagnostic flexible bronchoscopy in adults: Joint Indian Chest Society/National College of chest physicians (I)/Indian association for bronchology recommendations

“…[162] In a recent RCT, cricothyroid injection demonstrated superiority over the spray technique. [163] Another single small randomized study comparing two techniques of “spray-as-you-go,” using a spray catheter compared against standard injection through working channel of bronchoscope during EBUS found less cough with spray catheter, though there was no difference in total lignocaine dose or sedative requirements. [164] Although cricothyroid injection is likely more effective in controlling cough, it is an invasive procedure that is not widely practiced and has a learning curve for achieving acceptable expertise.…”

Flexible bronchoscopy during the COVID-19 pandemic: A concise clinical review and practical recommendations

“…This avoids disconnection of the ventilator circuit during bronchoscope introduction and also helps maintain positive end-expiratory pressure (UPP). It thus allows optimal simultaneous ventilation and the snug fit limits the air leak, thereby also the exposure during bronchoscopy Procedure duration should be minimized as far as possible, and, to achieve this, the following measures can be taken: Cricothyroid administration of local anesthetic is advisable over the spray-as-you-go method, as the former is associated with better patient comfort in terms of lesser cough and lower cumulative dose of the local anesthetic agent[ 15 ] (1A) Consider the evaluation of only those bronchopulmonary segments suspected to be involved as against screening normal airways as well (UPP) In intubated patients, avoid instillation of local anesthetic if patient is in complete paralysis (UPP). Bronchoscopist should hold the bronchoscope at an arm's length from himself/herself (UPP) There is an increased possibility of aerosol generation when oxygen is administered by nasal cannula at a flow rate >6 L/min.…”

“… Cricothyroid administration of local anesthetic is advisable over the spray-as-you-go method, as the former is associated with better patient comfort in terms of lesser cough and lower cumulative dose of the local anesthetic agent[ 15 ] (1A) Consider the evaluation of only those bronchopulmonary segments suspected to be involved as against screening normal airways as well (UPP) In intubated patients, avoid instillation of local anesthetic if patient is in complete paralysis (UPP). …”

“…Cricothyroid administration of local anesthetic is advisable over the spray-as-you-go method, as the former is associated with better patient comfort in terms of lesser cough and lower cumulative dose of the local anesthetic agent[ 15 ] (1A)…”

Conventional flexible bronchoscopy during the COVID pandemic: A consensus statement from the Indian Association for Bronchology

“… Prebronchoscopy nebulization with lidocaine should be avoided as they have a high tendency of aerosol production Prebronchoscopy nebulization with bronchodilators using nebulizers should be avoided to prevent aerosol production[ 21 ] In case inhaled bronchodilators need to be administered, these should be done with pressurized meter dose inhaler plus spacer device Preprocedure medications including dextromethorphan (90 mg to be given 60 min before procedure) and codeine (oral 0.4 mg/kg, 60 min before procedure) have been shown to improve the tolerance to procedure, reduce cough, and produce less expectoration postprocedure, and one of these may be administered, especially if bronchoscopy is being done without deep sedation or general anesthesia[ 23 24 25 ] Cricothyroid lidocaine administration is associated with less cough and superior operator-rated procedure satisfaction during bronchoscopy at a lower cumulative lidocaine dose[ 26 ] Patient should be made to wear a three-ply orofacial mask all through[ 21 ] If there are patients with other infectious diseases planned for bronchoscopy on the same day as the COVID-19 patients, the COVID cohort should be planned last to avoid fomite transmission. …”