Randomized, Controlled Trial of Licorice Gargle before Intubation for Elective Thoracic Surgery

This study enrolled 236 adult patients undergoing elective thoracic surgery requiring a double-lumen endotracheal tube. Gender, physical status, BMI, age, Mallampati score, smoking status, preoperative pain, surgery size, intervention and the outcomes (cough, sore throat and pain swallowing at various time points) are provided. The dataset is cleaned and complete (missing outcomes for 2 patients). There are no outliers or data problems (more details available below the variable definitions).

Usage

licorice_gargle

Format

A data frame with 235 observations and 19 variables

preOp_gender

Gender, numeric, 0 = Male; 1 = Female

preOp_asa

American Society of Anesthesiologists physical status, numeric, 1 = a normal healthy patient; 2 = a patient with mild systemic disease; 3 = a patient with severe systemic disease

preOp_calcBMI

Body mass index (kg/m^2), numeric, range:16-36

preOp_age

Age (years), numeric, range:18-86

preOp_mallampati

Mallampati score, with 1 = easy to intubate, 4= difficult intubation, numeric, 1 = soft palate, fauces, uvula, pillars visible; 2 = soft palate, fauces, uvula visible; 3 = soft palate, base of uvula visible; 4 = soft palate not visible at all

preOp_smoking

Smoking status, numeric, 1 = Current; 2 = Past; 3 = Never

preOp_pain

Preoperative pain, numeric, 0 = No; 1 = Yes

treat

Intervention, 0 = Sugar 5g; 1 = Licorice 0.5g

intraOp_surgerySize

Surgery size, numeric, 1 = Small (thoracoscopy); 2 = Medium (thoracotomy < 3 h); 3 = Large (thoracotomy > 3 h or blood loss > 1000 mL)

extubation_cough

Amount of coughing immediately after extubation, numeric, 0 = No cough; 1 = Mild; 2 = Moderate; 3 = Severe

pacu30min_cough

Amount of coughing at 30 minutes after arrival in PACU, numeric, 0 = No cough; 1 = Mild; 2 = Moderate; 3 = Severe

pacu30min_throatPain

Sore throat pain score at rest at 30 minutes after arrival in PACU (11 point Likert scale, 0=no pain, 10 = worst pain)

pacu30min_swallowPain

Sore throat pain score during swallowing at 30 minutes after arrival in PACU (11 point Likert scale, 0=no pain, 10 = worst pain), numeric, range: 0-10

pacu90min_cough

Amount of coughing at 90 minutes after arrival in PACU, numeric, 0 = No cough; 1 = Mild; 2 = Moderate; 3 = Severe

pacu90min_throatPain

Sore throat pain score at rest at 90 minutes after arrival in PACU (11 point Likert scale, 0=no pain, 10 = worst pain), numeric, range: 0-6)

postOp4hour_cough

Amount of coughing at 4 hours after surgery, numeric, 0 = No cough; 1 = Mild; 2 = Moderate; 3 = Severe, range: 0-2

postOp4hour_throatPain

Sore throat pain score at rest at 4 hours after surgery (11 point Likert scale, 0=no pain, 10 = worst pain), numeric, range: 0-6), numeric, range: 0- 7

pod1am_cough

Amount of coughing on the first postoperative morning, 0 = No cough; 1 = Mild; 2 = Moderate; 3 = Severe, numeric, range: 0- 3

pod1am_throatPain

Sore throat pain score at rest on the first postoperative morning (11 point Likert scale, 0=no pain, 10 = worst pain), numeric, range: 0-6), numeric, range: 0- 6

Source

These are data from a study by Ruetzler et al. 'A Randomized, Double-Blind Comparison of Licorice Versus Sugar-Water Gargle for Prevention of Postoperative Sore Throat and Postextubation Coughing'. Anesth Analg 2013; 117: 614 – 21.

Details

The Licorice Gargle dataset was contributed by Dr. Amy Nowacki, Associate Professor, Cleveland Clinic. Please refer to this resource as: Amy S. Nowacki, 'Licorice Gargle Dataset', TSHS Resources Portal (2017). Available at https://www.causeweb.org/tshs/licorice-gargle/.
Postoperative sore throat is a common and annoying complication of endotracheal intubation. Intubation with double-lumen tubes, which are much larger than conventional single-lumen tubes, are especially likely to provoke sore throats, with a reported incidence up to 90%. Presumably, postoperative sore throats are a consequence of local tissue trauma, due to laryngoscopy and/or endotracheal intubation, leading to inflammation of pharyngeal mucosa.
Nonpharmacological methods for preventing an intubation-related sore throat include using smaller-sized endotracheal tubes, lubricating the endotracheal tube with water-soluble jelly, and careful airway instrumentation as examples. Pharmacological measures for attenuating postoperative sore throats include inhalation of beclomethasone or fluticasone propionate; gargling with azulene sulfonate, aspirin, or ketamine; and gargling or spraying benzydamine hydrochloride on the endotracheal cuff for example. Each of these approaches and others not listed, however, has limitations and variable success rates; thus none has become established or is in routine clinical use.
Recently, a study reported that gargling with licorice halves the risk of sore throat after intubation with conventional endotracheal tubes, based on a study of just 40 patients. A number of active ingredients have been isolated from licorice, including glycyrrhizin, liquilitin, liquiritigenin, and glabridin. The glycyrrhizin component reportedly has anti-inflammatory and antiallergic properties. Liquilitin and liquiritigenin have peripheral and central antitussive properties. Glabridin has significant antioxidant and ulcer-healing properties, which might help heal pharyngeal and tracheal mucosa after minor injuries that often complicate laryngoscopy, intubation, and endotracheal tube cuff inflation.
This study tested the hypothesis that gargling with licorice solution immediately before induction of anesthesia prevents sore throat and postextubation coughing in patients intubated with double-lumen tubes.