|Year : 2018 | Volume
| Issue : 4 | Page : 891-896
Postintubation sequels: Influence of fluticasone and technique of intra-operative muscle relaxation
Choro Athiphro Kayina1, Rashmi Salhotra2, Ashok K Sethi2, Medha Mohta2, Arun K Sharma3
1 Department of Anaesthesia and Critical Care, AIIMS, Delhi, India
2 Department of Anaesthesiology and Critical Care, UCMS and GTBH, Delhi, India
3 Department of Community Medicine, UCMS, Delhi, India
|Date of Web Publication||18-Dec-2018|
Dr. Rashmi Salhotra
A-2/268, 2nd Floor, Paschim Vihar, New Delhi - 110 063
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Postintubation sequels (PIS) are a cause of serious concern in the postoperative period. Aim: The aim of this study is to find the influence of preoperative inhaled steroid and technique of muscle relaxation on PIS. Settings and Design: This prospective, exploratory pilot study was conducted on 120 adult American Society of Anesthesiologist physical status Class I and II patients undergoing general anesthesia (GA) with muscle relaxation and cuffed endotracheal tube (ETT) insertion. Patients and Methods: Patients were randomized into four groups as follows: intermittent muscle relaxation with preanesthetic inhalation of either distilled water puffs (Group ID) or fluticasone puffs (Group IF); continuous infusion of muscle relaxant with preanesthetic inhalation of either distilled water puffs (Group CD) or fluticasone puffs (Group CF). After induction of GA, ETT was inserted. The intra-cuff pressure was maintained constant. The trachea was extubated in the light plane in intermittent groups and in the deep plane in continuous groups. Statistical Analysis: Qualitative parameters were compared using the Chi-square test and quantitative parameters using repeated measure ANOVA followed by Tukey's test. Results: Group CF had significantly less incidence of sore throat and hoarseness compared to groups ID and IF. The severity of sore throat was more in groups ID and IF than in groups CF and CD (P < 0.002). The severity of hoarseness was least in group CF (23.3%) and highest in group IF (90%). None of the patients had a cough in group CF. The incidence and severity of dysphagia were significantly less in group CF as compared to other groups (P < 0.005 and P < 0.008, respectively). Conclusion: Continuous infusion of muscle relaxant with extubation in deep plane of anesthesia with preanesthetic inhalation of fluticasone puffs results in lesser incidence and severity of PIS.
Keywords: Fluticasone, intratracheal, intubation, muscle relaxants, nondepolarizing, sore throat
|How to cite this article:|
Kayina CA, Salhotra R, Sethi AK, Mohta M, Sharma AK. Postintubation sequels: Influence of fluticasone and technique of intra-operative muscle relaxation. Anesth Essays Res 2018;12:891-6
|How to cite this URL:|
Kayina CA, Salhotra R, Sethi AK, Mohta M, Sharma AK. Postintubation sequels: Influence of fluticasone and technique of intra-operative muscle relaxation. Anesth Essays Res [serial online] 2018 [cited 2019 Jun 25];12:891-6. Available from: http://www.aeronline.org/text.asp?2018/12/4/891/247653
| Introduction|| |
Sore throat, hoarseness, cough, dysphonia, and dysphagia are common postintubation complaints among patients who have undergone procedures with the insertion of an endotracheal tube (ETT). The incidence of postoperative sore throat can be as high as 62%, and hoarseness can affect 32%–55%, of patients with about 3% of cases reported to develop permanent hoarseness. These are thus a cause of significant patient discomfort and dissatisfaction in the postoperative period and may even require treatment with supplementary medications.
The factors identified for the occurrence of these complications include anesthetic drugs and gases, excessive pharyngeal suctioning, site of surgery,, age and gender,, size and type of ETT, cuff design, size and pressure,, number of trials and duration of intubation,, intubation with or without muscle relaxation,, movement of ETT during surgery, bucking and coughing on ETT intraoperatively or during extubation. One of the theories postulated for the occurrence of postintubation sequels (PIS) is local irritation and inflammation due to trauma to the airway.,,, Various treatment modalities have been used to attenuate PIS but with varying efficacy. These include gargling with ketamine,,, aspirin and benzydamine,,, prophylactic oral gabapentin, magnesium lozenges and gargles, and strepsils tablets, and lignocaine gel and spray. Steroids possess anti-inflammatory properties, and for this reason, betamethasone gel, beclomethasone, and fluticasone inhalation and intravenous (iv) dexamethasone have been used for attenuating the postoperative sore throat.
Extensive search of literature shows that there are no studies which assess the role of preoperative inhaled steroid administration and intra-operative technique of muscle relaxation on the development of PIS. We hypothesized that preanesthetic inhaled fluticasone due to its anti-inflammatory property and continuous administration of muscle relaxant infusion would lower the incidence and severity of PIS. Therefore, this study was designed to find the effect of administration of preanesthetic inhaled fluticasone or distilled water puffs and two techniques of muscle relaxation (intermittent muscle relaxant and awake extubation versus continuous infusion of muscle relaxant and extubation in deep plane) on the incidence and severity of PIS in the general population undergoing surgical procedure requiring general anesthesia (GA) with cuffed ETT insertion.
| Patients and Methods|| |
Institutional Ethics Committee-Human Research approval was obtained before initiating the study. All the procedures followed were in accordance with the Helsinki Declaration of 1975, as revised in 2000. Written informed consent was obtained from all the participating patients. The study was conducted over 18 months between November 2013 and April 2015.
This exploratory, pilot study was conducted on patients between 18 and 60 years of age belonging to the American Society of Anesthesiologist physical status class I and II, undergoing GA with muscle relaxation and cuffed ETT insertion for airway maintenance for elective surgical procedures. Smokers, patients with history of upper respiratory tract infection or on inhaled or oral steroid use in the last 1 month, anticipated difficult airway, reactive airway disease, surgeries requiring repeated oral or tracheal suctioning, pharyngeal packing, Ryle's tube insertion, head, neck or oral surgeries, patients requiring re-intubation, nasotracheal intubation, and change in position after intubation were excluded. As this was undertaken as a pilot study, 30 cases were included in each group (a total of 120 patients).
Demographic characteristics of all patients were noted and preanesthetic evaluation was done. Preanesthetic medication, ranitidine 150 mg orally and alprazolam 0.25 mg orally was administered on the night before and on the morning of surgery. Patients were randomly divided into four groups using computer-generated random number table:
- Group ID–Preanesthetic inhalation of distilled water puffs and intermittent muscle relaxant with extubation in awake state or light plane of anesthesia
- Group IF–Preanesthetic inhalation of fluticasone puffs and intermittent muscle relaxant with extubation in awake state or light plane of anesthesia
- Group CD–Preanesthetic inhalation of distilled water puffs and continuous infusion of muscle relaxant with extubation in deep plane of anesthesia
- Group CF–Preanesthetic inhalation of fluticasone puffs and continuous infusion of muscle relaxant with extubation in deep plane of anesthesia.
Four puffs of distilled water were administered through the mucosal atomizing device (MAD) in groups ID and CD whereas four puffs of fluticasone 125 μg (total of 500 μg) were administered using spacer device during two consecutive deep inspirations in groups IF and CF by an independent anesthesiologist not involved in assessing the postoperative outcome. To ensure blinding, the observer recording postoperative outcome measures was not present inside the operating theater and was not aware of the preoperative inhalation drug administered or the technique of intra-operative muscle relaxation adopted.
Iv access was secured and routine monitors including electrocardiography, noninvasive blood pressure and pulse-oximeter were attached. Anesthesia was initiated by administering injection morphine 0.1 mg/kg iv and induction with injection propofol 2–3 mg/kg followed by injection vecuronium 0.1 mg/kg. Macintosh laryngoscope blade was used for laryngoscopy and trachea was intubated with an appropriately sized high volume low pressure cuffed ETT by an anesthesiologist who had at least 1 year of experience in conventional laryngoscopy and intubation. Cuff of the ETT was inflated to a pressure of 25 cm H2O by using a manual cuff inflator with manometer, and it was maintained at 25 cmH2O by intermittent adjustments every 30 min. Anesthesia was maintained with N2O and isoflurane in O2 and intermittent or continuous muscle relaxation technique according to the groups allocated.
Intermittent muscle relaxant technique and extubation in the awake state
This technique was used in groups ID and IF. Intubation was done after 3 min of vecuronium administration. Intermittent boluses of ¼th of the intubating dose of vecuronium were given when the patient showed signs of diaphragmatic activity or reservoir bag movement, as during conventional anesthesia. At the end of the surgery, the residual neuromuscular (NM) blockade was reversed with injection neostigmine (50 μg/kg iv.) and injection atropine (20 μg/kg iv.) after the return of spontaneous respiratory efforts. Laryngoscopy was done to visualize any oropharyngeal injuries and for performing suction under vision, and extubation was done when the patient was awake, and protective reflexes were regained.
Continuous muscle relaxant technique with extubation in deep plane of anesthesia
This technique was used in groups CD and CF. Train-of-Four (TOF) method of NM monitoring was used for monitoring the degree of relaxation. TOF monitoring was started after the loss of consciousness following induction of anesthesia, and endotracheal intubation was done after the disappearance of all the four TOF responses following administration of vecuronium. TOF monitoring was continued throughout the procedure. Infusion of vecuronium was initiated at the rate of 0.8–1.0 μg/kg/min with a syringe infusion pump when the TOF = 1. Dose of vecuronium infusion was adjusted to maintain TOF ≤1 at all times. The infusion of muscle relaxant was stopped at the time when the surgical procedure was expected to be over, but the administration of the volatile anesthetic was continued to maintain adequate depth of anesthesia to prevent coughing or bucking over the ETT. Reversal of residual NM block was done with injection neostigmine (50 μg/kg iv.) and injection atropine (20 μg/kg iv.) when the TOF count was ≥2. Laryngoscopy was done to visualize any oropharyngeal injuries and for performing suction under vision. Extubation was done when TOF ratio was ≥0.7. Injury to pharyngeal and supraglottic structures at the time of laryngoscopy and just before extubation was noted. The presence of blood over the ETT after extubation was looked for.
Sore throat was defined as a constant pain or discomfort in the throat independent of swallowing. Dysphonia was defined as difficulty in speaking or pain on speaking and dysphagia was defined as difficulty or pain provoked by swallowing. Patients were interviewed at 2, 6, and 24 h postoperatively and the incidence of PIS was noted, and the severity was graded according to [Table 1]. The occurrence of blood streaked expectoration at any time during the first 24 h after extubation was also recorded.
Sample size calculation and statistical analysis
Since this was undertaken as a pilot study, 30 patients were enrolled in each group making a total of 120 patients. All the four groups were compared using Chi-square test/Fisher's exact test for qualitative variables. Within and between the groups comparisons were obtained by repeated measure ANOVA followed by Tukey's test for quantitative parameters. Nonparametric tests (McNemar test and Mann–Whitney Test) were applied wherever appropriate, and P value was considered after Bonferroni correction. A value of P < 0.05 was considered as statistically significant. All the statistical analysis was carried out using SPSS Statistics for Windows, Version 20.0. (Armonk, NY: IBM Corp.).
| Results|| |
The demographic profile and other patient characteristics are shown in [Table 2]. Various sizes of ETT used in the patients in the four groups were 7.0, 7.5, 8.0, or 8.5 mm ID. The time interval between fluticasone and distilled water puffs administration and intubation was statistically similar among all the four groups (P = 0.303). The total duration of ETT in situ was also statistically similar among all the four groups (P = 0.830). However, there was a statistically significant difference between the total dose of vecuronium required between the groups (P < 0.05). More dose of vecuronium was used in the continuous infusion groups.
[Table 3] shows the incidence of PIS in the four groups. The incidence of sore throat, hoarseness, cough, dysphonia, and dysphagia was calculated by observing their presence at 0, 2, 6, and 24 h postoperatively. Patients in group CF had significantly less sore throat compared to those in groups ID and IF. Incidence of hoarseness was least in group CF (23.3%) when compared to all the other groups and was highest in group IF (90%). None of the patients had a cough in group CF, in contrast to 30% of patients in group ID, 20% in group IF, and 6.6% in group CD. Incidence of dysphagia was significantly higher in group ID as compared to continuous infusion groups (CD and CF). The incidence of dysphonia was clinically higher in group ID as compared to all the other groups. However, it failed to achieve statistical significance (P = 0.188).
|Table 3: Comparison of incidence of postintubation sequels in different groups (n=30)|
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None of the patients in any of the four groups showed any evidence of blood streaked expectoration or evidence of any nerve injury at any point in time.
[Table 4] shows the comparison of overall severity of PIS in different groups. The severity was graded using predefined scores [Table 1]. The mean value of the maximum scores recorded over the entire observation period was taken to represent the overall severity of the PIS. The severity of sore throat was more in intermittent muscle relaxant groups (group ID and IF) than in continuous infusion groups (group CD and CF). The severity was maximum in group ID and comparable in groups CD and CF. Group CF patients had the least severity of hoarseness as compared to all the other groups. Patients in the intermittent muscle relaxant groups (ID and IF) developed more severe hoarseness compared to those in the continuous infusion groups (CD and CF). Group ID had significantly more severe dysphagia compared to both continuous infusion groups (CD and CF). There was no statistically significant difference between the severity of dysphonia in all the groups. Only one patient in each of the two groups, ID and IF (3.33%), developed severe (grade 3) hoarseness and sore throat, respectively. None of the patients in continuous infusion groups (CD and CF) developed severe grade PIS.
|Table 4: Comparison of severity of postintubation sequels in different groups|
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[Table 5] depicts the correlation of trauma to the development of PIS. Trauma was present in 16 patients (16.3%) out of 120 patients as assessed on preextubation direct laryngoscopic examination. It was observed that the incidence of sore throat, hoarseness, cough, dysphonia, dysphagia, and blood streak expectoration was statistically similar in all patients irrespective of the presence or absence of trauma on preextubation laryngoscopy.
The incidence of developing PIS was compared with blood staining on ETT [Table 6]. Blood stained ETT was present in 13 (10.8%) out of 120 patients when examined with the naked eye after extubation. The incidence of sore throat, hoarseness, cough, and dysphagia was statistically similar in all the groups. However, dysphonia was found in 53.84% patients who had blood stained ETT compared to only 13.08% when no blood staining was seen (P < 0.001).
|Table 6: Incidence of postintubation sequels with/without blood stained endotracheal tube|
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| Discussion|| |
This study was designed to find the influence of preanesthetic inhaled fluticasone and the effect of muscle relaxant technique on the development of PIS. The major findings of the study were that the overall incidence of sore throat was 38.5% and hoarseness was 60.6%. The severity of sore throat and hoarseness was least in patients who received both fluticasone puffs and continuous infusion of muscle relaxant as opposed to intermittent muscle relaxation groups with or without preoperative fluticasone. Patients who received continuous muscle relaxation had a significantly lesser incidence of cough. There was no influence of either the technique of muscle relaxation or steroid administration on the incidence and severity of dysphonia in this study. Dysphagia was the highest in the group where neither fluticasone puffs nor muscle relaxant infusion was used.
The strengths of the study are that to the best of our knowledge, it is the first study to have compared the influence of technique of muscle relaxant and preoperative steroid inhalation on the incidence and severity of PIS. The PIS observed were not only limited to sore throat and hoarseness, which most of the other studies have concentrated on but also it consisted of a spectrum of complications encompassing cough, dysphonia, and dysphagia.
The overall incidence of sore throat observed in this study was similar to that reported in the literature. The combined effect of good intra-operative muscle relaxation with extubation in the deep plane and anti-inflammatory effect of preoperative steroid may have been responsible for the reduced incidence as well as the severity of all the PIS. Only steroid administration without continuous muscle relaxation did not result in a reduced incidence of PIS. Combes et al. found that the use of muscle relaxant reduced the incidence of sore throat. There are no comments on the severity of sore throat in this study. Studies conducted by Ayoub et al. and Honarmand and Safavi reported lower sore throat grades in the patients where steroids were used. Tazeh-Kand et al., reported a reduction in the incidence of sore throat with the use of fluticasone puffs with none of the patient reporting severe or moderate grades of sore throat. In our study also, steroid use preoperatively was associated with a reduction in the incidence and severity of PIS.
Past studies using inhaled steroids and steroid smeared ETT have shown to significantly reduce the incidence and severity of hoarseness, similar to our findings. However, the role of muscle relaxation for reducing hoarseness was not found to be promising by Honarmand and Safavi Similarly, in our study, steroid with intermittent muscle relaxation was not effective in reducing the incidence and severity of hoarseness. However, the combined effect of continuous relaxation and steroid inhalation was associated with reduction in the hoarseness.
In the present study, patients who received continuous muscle relaxation and steroid did not complain of cough in the first 24 h. The incidence was a mere 6.6% with continuous infusion without steroid, 20% with steroid and intermittent muscle relaxation and 30% with intermittent relaxation without steroid. Again, the role of continuous muscle relaxation was much higher in contributing to the nondevelopment of cough than steroid. Somewhat similar to our findings are the observations by Ayoub et al. who reported that steroid gel application on the ETT did not reduce the incidence of cough. Fluticasone administration has shown a reduction in the incidence of cough from 18.3% to 3.33% in a previous study. We also found that fluticasone reduced cough (from 30% without steroid to 20% with steroid in intermittent groups), but its effect was more pronounced when combined with continuous muscle relaxation (6.6% without steroid to 0% with steroid in continuous groups).
The development of dysphonia was not influenced by either the technique of muscle relaxation or steroid administration in this study. Dysphagia was significantly higher in the group where neither fluticasone puffs nor muscle relaxant infusion was used. However, it can be clearly seen that the continuous infusion of muscle relaxant with or without fluticasone administration are superior to no fluticasone and intermittent muscle relaxation. In studies done by Honarmand and Safavi steroid was found to be ineffective in reducing postoperative dysphagia.
In a previous study by Mencke et al., it was found that better intubating conditions with the use of muscle relaxant during intubation were associated with less hoarseness and vocal cord sequels. In the present study also, since all the patients received muscle relaxant for intubation, the incidence of trauma was 13.3% and it did not result in an increase in PIS.
There are a few limitations to this study. First, the administration of distilled water puffs was done using MAD device while fluticasone was administered via a spacer device. The particle size produced by the two methods is different which may have influenced the results. Second, in the intermittent muscle relaxation groups, top-up of relaxant was given based on the subjective criteria, unlike the continuous infusion groups where NM monitoring was performed. Another reason is the criteria for deep extubation that were used in our study (TOF >0.7) have now been revised to TOF >0.9.
| Conclusion|| |
Based on the observations of our study, we conclude that preanesthetic inhalation of fluticasone puffs and continuous infusion of muscle relaxant with extubation in deep plane of anesthesia results in lesser incidence and severity of sore throat, hoarseness, cough, and dysphagia. Fluticasone inhalation alone does not have any beneficial effect on reducing the PIS. Therefore, we recommend the use of fluticasone puffs and continuous infusion of muscle relaxant to minimize PIS.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
El-Boghdadly K, Bailey CR, Wiles MD. Postoperative sore throat: A systematic review. Anaesthesia 2016;71:706-17.
Jones MW, Catling S, Evans E, Green DH, Green JR. Hoarseness after tracheal intubation. Anaesthesia 1992;47:213-6.
Maruyama K, Sakai H, Miyazawa H, Toda N, Iinuma Y, Mochizuki N, et al.
Sore throat and hoarseness after total intravenous anaesthesia. Br J Anaesth 2004;92:541-3.
Christensen AM, Willemoes-Larsen H, Lundby L, Jakobsen KB. Postoperative throat complaints after tracheal intubation. Br J Anaesth 1994;73:786-7.
Minamiguchi M, Tanaka Y, Kitagawa K, Inoue S, Kawaguchi M, Kirita T, et al.
Evaluation of factors associated with postoperative sore throat. Masui 2014;63:401-5.
Jaensson M, Gupta A, Nilsson UG. Gender differences in risk factors for airway symptoms following tracheal intubation. Acta Anaesthesiol Scand 2012;56:1306-13.
Seegobin RD, van Hasselt GL. Endotracheal cuff pressure and tracheal mucosal blood flow: Endoscopic study of effects of four large volume cuffs. Br Med J (Clin Res Ed) 1984;288:965-8.
Jaensson M, Gupta A, Nilsson UG. Risk factors for development of postoperative sore throat and hoarseness after endotracheal intubation in women: A secondary analysis. AANA J 2012;80:S67-73.
Liu J, Zhang X, Gong W, Li S, Wang F, Fu S, et al.
Correlations between controlled endotracheal tube cuff pressure and postprocedural complications: A multicenter study. Anesth Analg 2010;111:1133-7.
Mencke T, Echternach M, Plinkert PK, Johann U, Afan N, Rensing H, et al.
Does the timing of tracheal intubation based on neuromuscular monitoring decrease laryngeal injury? A randomized, prospective, controlled trial. Anesth Analg 2006;102:306-12.
Rimaniol JM, Kersuzan Y, Duvaldestin P. Intubating conditions using cisatracurium after induction of anaesthesia with thiopentone. Anaesthesia 1997;52:998-1000.
McHardy FE, Chung F. Postoperative sore throat: Cause, prevention and treatment. Anaesthesia 1999;54:444-53.
Sumathi PA, Shenoy T, Ambareesha M, Krishna HM. Controlled comparison between betamethasone gel and lidocaine jelly applied over tracheal tube to reduce postoperative sore throat, cough, and hoarseness of voice. Br J Anaesth 2008;100:215-8.
Chen YQ. Prophylactic effectiveness of budesonide inhalation in reducing postoperative throat complaints. J Anesth Clin Res 2012;3:3-6.
Higgins PP, Chung F, Mezei G. Postoperative sore throat after ambulatory surgery. Br J Anaesth 2002;88:582-4.
Rudra A, Ray S, Chatterjee S, Ahmed A, Ghosh S. Gargling with ketamine attenuates the postoperative sore throat. Indian J Anaesth 2009;53:40-3.
] [Full text]
Canbay O, Celebi N, Sahin A, Celiker V, Ozgen S, Aypar U, et al.
Ketamine gargle for attenuating postoperative sore throat. Br J Anaesth 2008;100:490-3.
Teymourian H, Mohajerani SA, Farahbod A. Magnesium and ketamine gargle and postoperative sore throat. Anesth Pain Med 2015;5:e22367.
Agarwal A, Nath SS, Goswami D, Gupta D, Dhiraaj S, Singh PK, et al.
An evaluation of the efficacy of aspirin and benzydamine hydrochloride gargle for attenuating postoperative sore throat: A prospective, randomized, single-blind study. Anesth Analg 2006;103:1001-3.
Chang JE, Min SW, Kim CS, Han SH, Kwon YS, Hwang JY, et al.
Effect of prophylactic benzydamine hydrochloride on postoperative sore throat and hoarseness after tracheal intubation using a double-lumen endobronchial tube: A randomized controlled trial. Can J Anaesth 2015;62:1097-103.
Chen CY, Kuo CJ, Lee YW, Lam F, Tam KW. Benzydamine hydrochloride on postoperative sore throat: A meta-analysis of randomized controlled trials. Can J Anaesth 2014;61:220-8.
Lee JH, Lee HK, Chun NH, So Y, Lim CY. The prophylactic effects of gabapentin on postoperative sore throat after thyroid surgery. Korean J Anesthesiol 2013;64:138-42.
Borazan H, Kececioglu A, Okesli S, Otelcioglu S. Oral magnesium lozenge reduces postoperative sore throat: A randomized, prospective, placebo-controlled study. Anesthesiology 2012;117:512-8.
Ebneshahidi A, Mohseni M. Strepsils® tablets reduce sore throat and hoarseness after tracheal intubation. Anesth Analg 2010;111:892-4.
Klemola UM, Saarnivaara L, Yrjölä H. Post-operative sore throat: Effect of lignocaine jelly and spray with endotracheal intubation. Eur J Anaesthesiol 1988;5:391-9.
Kazemi A, Amini A. The effect of betamethasone gel in reducing sore throat, cough, and hoarseness after laryngo-tracheal intubation. Middle East J Anaesthesiol 2007;19:197-204.
Honarmand A, Safavi M. Beclomethasone inhaler versus intravenous lidocaine in the prevention of postoperative airway and throat complaints: A randomized, controlled trial. Ann Saudi Med 2008;28:11-6.
] [Full text]
Tazeh-Kand NF, Eslami B, Mohammadian K. Inhaled fluticasone propionate reduces postoperative sore throat, cough, and hoarseness. Anesth Analg 2010;111:895-8.
Park SY, Kim SH, Lee AR, Cho SH, Chae WS, Jin HC, et al.
Prophylactic effect of dexamethasone in reducing postoperative sore throat. Korean J Anesthesiol 2010;58:15-9.
Combes X, Andriamifidy L, Dufresne E, Suen P, Sauvat S, Scherrer E, et al.
Comparison of two induction regimens using or not using muscle relaxant: Impact on postoperative upper airway discomfort. Br J Anaesth 2007;99:276-81.
Ayoub CM, Ghobashy A, Koch ME, McGrimley L, Pascale V, Qadir S, et al.
Widespread application of topical steroids to decrease sore throat, hoarseness, and cough after tracheal intubation. Anesth Analg 1998;87:714-6.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]