Comparison of Postoperative Sore Throat and Hoarseness Between Two Types of Double-Lumen Endobronchial Tubes: A Randomized Controlled Trial Joonpyo Jeon, MD, Kusang Lee, MD, Guyeon Ahn, MS, Jingyoung Lee, MS, and Wonjung Hwang, MD Objective: Two types of material are used to manufacture double-lumen endobronchial tubes (DLTs): Polyvinylchloride (PVC) and silicon. PVC DLTs (Broncho-Cath) and silicon DLTs (Silbroncho) not only differ in material, but also subtly differ in structure. The goal of this study was to determine whether the incidences of postoperative sore throat and hoarseness differed between PVC DLTs and silicon DLTs. Design: Prospective, single-blind, balanced (1:1), randomized, controlled trial. Setting: Single university hospital. Participants: Sixty ASA I-II patients, aged 20 to 65 years, scheduled for thoracoscopic pulmonary lobectomy. Interventions: Patients were randomized into the Broncho-cath group (group B, n ¼ 30) and the Silbroncho group (group S, n ¼ 30). Intubation was performed with DLT according to the allocated group by an anesthesiologist.
Measurements and Main Results: The incidence of sore throat and hoarseness was evaluated at 1 hour and 24 hours after DLT extubation. The intensity of sore throat was assessed by visual analog scale (VAS o 0-10) at 1, 2, 4, 12, and 24 hours after DLT extubation. The incidence of sore throat was significantly lower in group S compared with that in group B at 1 h (30% v 66.7%, p ¼ 0.018) and 24 hours (10% v 43.3%, p ¼ 0.014). No significant difference was observed in the incidence of hoarseness between the 2 groups. The VAS scores for sore throat in group B were significantly higher than those in group S throughout the study (p o 0.05). Conclusions: The use of silicon DLTs resulted in a lower incidence of postoperative sore throat than did the use of PVC DLTs. & 2014 Elsevier Inc. All rights reserved.
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recent respiratory infection (o1 month), prior treatment with steroid or opioid, and a history of disease or surgery on the oral cavity or pharynx. Patients were randomized into the following 2 groups: The Bronchocath group (group B, n ¼ 30) and the Silbroncho group (group S, n ¼ 30). The group allocation was concealed in opaque envelopes that were opened by a staff anesthesiologist immediately before induction of anesthesia. After identifying the randomization code, the anesthesiologist prepared the left-sided DLT according to the group allocation and conducted the entire course of anesthesia, including intubations in all patients and evaluation of parameters associated with intubation. Another anesthesiologist, who was blinded to the group allocation, evaluated and recorded all perioperative parameters except those associated with intubation. The same surgeon conducted all surgeries using the same surgical method. The patients and the surgeon in charge were blinded to the group allocation for the duration of the study. Premedication was omitted, and routine monitoring was performed after arrival in the operating room. Anesthesia was induced with 2 mg/kg of propofol and 0.8 mg/kg of rocuronium. Endotracheal intubation was performed after loss of all 4 twitches of train-of-four stimulation on the ulnar nerve. DLTs were lubricated with distilled water. A direct laryngoscopy was performed using a standard 3 or 4 Macintosh metal blade. The size of the DLT was determined by measuring the left main bronchial diameter on chest computed tomography (CT): 32 Fr for diameter o10 mm, 35 Fr for 10 mm r diameter o 11 mm, and 37 Fr for 11 mm r diameter o 12 mm.5 The stylet was removed immediately after the tip of the endobronchial lumen passed the vocal cord. The position of the DLT was adjusted with fiberoptic bronchoscopy (LF-GP; Olympus, Tokyo, Japan) immediately after intubation and after turning
OSTOPERATIVE SORE THROAT and hoarseness are common complications related to endotracheal intubation and occur in 6.9%-90% of patients.1,2 A double-lumen endobronchial tube (DLT) is the type most widely used for one-lung ventilation to improve the surgical field during thoracic surgery. The larger outer diameter of a DLT compared with an endotracheal tube increases the incidence of postoperative sore throat and hoarseness.3 Two types of material are used to manufacture DLTs: Polyvinylchloride (PVC) and silicon. PVC DLTs (BronchoCath; Mallinckrodt, Hazelwood, MO) and silicon DLTs (Silbroncho; Fugi, Tokyo, Japan) not only differ in material, but also subtly differ in structure. The Silbroncho has a softer body and a more flexible tip on the endobronchial lumen with less curvature. Burton et al reported that use of the softer and more flexible PVC DLT with a gentle distal curve structure decreased complications, such as unsuccessful and difficult intubation, tube dislodgement, unsatisfactory deflation, tube malpositioning, and hypoxemia, compared with use of the rubber DLT.4 Similarly, it was hypothesized for the present study that the use of a silicon DLT would reduce complications from airway irritation during intubation compared with that of the PVC DLT. This study was conducted to determine whether the incidence of postoperative sore throat and hoarseness differed between PVC DLTs and silicon DLTs. METHODS This study was a prospective, single-blind, balanced (1:1), randomized controlled trial. No changes to the design or protocol were made during the course of the study. This study was approved by the institutional review board of the hospital (No.: KC12EISI0132) and registered at the Clinical Research Information Service of the Republic of Korea (No.: KCT0000676). Informed consent was obtained from all study subjects. Sixty patients with ASA class I or II, aged 20-65 years, and scheduled for elective video-assisted thoracoscopic pulmonary lobectomy were enrolled. Exclusion criteria included pre-existing sore throat and hoarseness, known difficult intubation, mouth opening o3.5 cm, Mallampatti score of 3 or 4, Cormack score of 3 or 4,
KEY WORDS: intubation, postoperative complications, sore throat, hoarseness, double lumen tubes, thoracic anesthesia
From the Department of Anesthesiology, The Catholic University of Korea, Seoul St. Maryʼs Hospital, Seoul, Korea. Address reprint requests to Wonjung Hwang, MD, Department of Anesthesiology, The Catholic University of Korea, Seoul St. Maryʼs Hospital, Seoul, Korea, 202 Banpo-Daero, Seocho-gu, Seoul 137-701, Korea. E-mail: [email protected] © 2014 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2014.05.028
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the patient to the lateral position. The pressures of both tracheal and bronchial cuffs were monitored with a noninvasive manometer (ControlInflator; VBM, Sulz, Germany) every 20 minutes and maintained at o20 cmH2O during anesthesia. Anesthesia was maintained with propofol and remifentanil by a target-controlled infusion (Orchestra Base Primea; Fresenius Vial, Grenoble, France). Muscle relaxation was achieved with a 5 μg/kg/min atracurium infusion during the course of surgery to prevent coughing or bucking. Mechanical ventilation was controlled to maintain normocarbia with an inspired oxygen concentration of 100%. The infusion of muscle relaxant was discontinued beginning with surgical field irrigation. The intercostal block was performed by the surgeon before wound closure in all patients. Neuromuscular block was reversed with 0.4 mg of glycopyrrolate and 10 mg of pyridostigmine. At the end of surgery, the train-of-four ratio was measured, and the patients were extubated. Oropharyngeal suction was performed with a 14-Fr soft catheter under direct vision. Intravenous patientcontrolled analgesia (PCA) infusion was initiated after extubation. The PCA consisted of 10 mg/mL of fentanyl and 1.2 mg/mL of ketoracin in normal saline at a continuous infusion rate of 1 mL/hour with a 1-mL bolus and a lockout time of 10 minutes. When the patient suffered from wound pain of severity 45 on a 10-cm visual analog scale (VAS, 0-10: Where 0 means the absence of pain and 10 represents the worst pain imaginable), 25 mg of meperidine were injected intravenously. The primary outcome measure was the incidence of sore throat, and the secondary outcome measure was the incidence of hoarseness recorded at 1 hour and 24 hours after DLT extubation. Postoperative sore throat was defined as pain at the larynx or pharynx, and hoarseness was defined as a harsh or strained voice. In addition, the intensity of sore throat was assessed by the VAS at 1, 2, 4, 12, and 24 hours after DLT extubation. The severity of wound pain assessed by VAS, total volume of PCA infused, and frequency of additional analgesic were recorded at 1 hour and 24 hours after DLT extubation. Parameters associated with DLT intubation also were recorded: Cormack and Lehane score, resistance to DLT insertion classified into none/mild/ severe, the number of intubation attempts (advances of DLT through vocal cord), the time to complete successful DLT intubation from the beginning of laryngoscopy, the number of DLT repositionings, and the duration of DLT intubation. No changes to outcome assessments were made during the trial. In a pilot study conducted with 18 patients, the incidence of sore throat was 60% after PVC DLT intubation and 20% after silicon DLT intubation. To obtain an 80% chance of finding a 67% decrease in the incidence of sore throat (60%-20%) at 1 hour and 24 hours after extubation with α ¼ 0.025 (two-tailed), 24 patients were required for each group. Taking potential dropouts into consideration, 30 patients were included in each group. Data are presented as mean ⫾ standard deviation or absolute value. According to an analysis of distribution, Student’s t test or the MannWhitney U-test was used to compare between-group differences in age, height, weight, time to complete intubation and duration of intubation,
Table 2. Variables Associated With Tracheal Intubation
Size of DLT (Fr), 37/ 35 Cormack and Lehane score, 1/2 Resistance to DLT insertion, none/ mild/ severe Number of intubation attempts, 1/2 Time for complete DLT intubation, sec Number of DLT repositioning, 0/1 Duration of DLT intubation, min
Group B
Group S
p
(n ¼ 30)
(n ¼ 30)
Value
17/13 25/5 18/8/4
13/17 22/8 14/15/1
0.302 0.431 0.109
26/4 12.2 (6.2)
27/3 12.5 (6.0)
1.000 0.842
21/9 22/8 0.774 193.1 (80.0) 172.8 (45.2) 0.231
NOTE. Values are expressed as number or mean (SD). Abbreviations: DLT, double-lumen endobronchial tube; SD, standard deviation.
severity of wound pain, and total volume of PCA infused. Fisher’s exact test was used to compare other demographic data, the Cormack and Lehane score, resistance to DLT insertion, the number of intubation trials, the number of times the DLT was repositioned, the frequency of additional analgesics administered, and the incidence of sore throat and hoarseness. The intensity of sore throat was compared by repeated-measures analysis of variance and the unpaired t test with Bonferroni correction for multiple comparisons if any significant difference was found between groups. No interim analyses were performed. SPSS software for Windows ver. 15.0 (SPSS Inc., Chicago, IL) was used for the analysis. All p values o0.05 were considered to indicate statistical significance. RESULTS
Sixty patients were assessed for eligibility, and all patients were included. Thirty patients each were randomized to groups B and S. No patient was excluded during the study due to failed intubation. All data obtained from the 60 patients were analyzed. Demographic data, including history of smoking, are shown in Table 1. No significant differences were observed between the 2 groups for the demographic data. Variables associated with tracheal intubation are listed in Table 2. The Cormack and Lehane score, resistance to DLT insertion, number of intubation attempts, time to complete DLT intubation, number of DLT repositionings, and duration of DLT intubation were comparable in both groups. The incidence of sore throat was significantly lower in group S than in group B at 1 hour and 24 hours (Table 3). Nine patients (30%) in group S had sore throat at 1 hour after DLT extubation, whereas 20 patients (66.7%) in group B had sore throat (p ¼ 0.018). At 24 hours after DLT extubation, the incidence of sore throat decreased from 1 hour after DLT Table 3. Incidence of Postoperative Sore Throat and Hoarseness
Table 1. Patient Characteristics Characteristics
Age, yr Sex, M/F Height, cm Weight, kg ASA physical status, I/II Smoking, Y/N
Group B (n ¼ 30)
Group S (n ¼ 30)
p Value
61.5 (5.6) 17/13 161.0 (9.3) 63.5 (10.5) 6/24 14/16
60.5 (8.5) 13/17 158.1 (8.7) 58.5 (9.9) 4/26 13/17
0.568 0.302 0.217 0.065 0.731 0.602
NOTE. Values are number or mean (SD). Abbreviations: ASA, American Society of Anesthesiologists; F, female; M, male; N, no; SD, standard deviation; Y, yes.
Group B
Group S
(n ¼ 30)
(n ¼ 30)
p Value
(66.7%) (26.7%)
9 (30%) 4 (13.3%)
0.018* 0.333
(43.3%) (3.3%)
3 (10%) 1 (3.3%)
0.014* 1.0
1 h after DLT extubation Sore throat 20 Hoarseness 8 24 h after DLT extubation Sore throat 13 Hoarseness 1
NOTE. Values are expressed as number (proportion). Abbreviation: DLT, double-lumen endobronchial tube. * p values were adjusted using Bonferroni correction.
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COMPARISON OF DOUBLE-LUMEN ENDOBRONCHIAL TUBES
Fig 1. Intensity of sore throat after double-lumen endobronchial tube extubation; *p o 0.05 compared with group B. Abbreviation: VAS, visual analog scale.
extubation in each group. However, 3 patients (10%) presented with sore throat in group S compared with 13 patients (43.3%) in group B (p ¼ 0.014). Fig 1 shows the intensity of sore throat as assessed by the VAS score. The VAS scores decreased over time in both groups; however, the VAS scores in group B were significantly higher than those in group S throughout the study. The VAS scores were 3.43 ⫾ 2.57 in group B vs. 1.00 ⫾ 1.62 in group S (p o 0.001) at 1 hour after DLT extubation and 1.40 ⫾ 1.73 in group B versus 0.20 ⫾ 0.66 in group S (p ¼ 0.005) at 24 hours after DLT extubation. The severity of wound pain, total volume of PCA infused, and frequency of additional analgesics were not different between the 2 groups (Table 4). The intensity of sore throat and the severity of wound pain were comparable in patients with sore throat in group B; the VAS score of sore throat was 5.15 ⫾ 0.88 and that of wound pain was 5.00 ⫾ 1.08 at 1 hour (n ¼ 20, p ¼ 0.666). The VAS score of sore throat was 3.23 ⫾ 0.93 and that of wound pain was 3.00 ⫾ 0.71 at 24 hours (n ¼ 13, p ¼ 0.534). The incidence of hoarseness also decreased over time but was not significantly different between the 2 groups (Table 3).
curved endobronchial lumen and needs more frequent manipulation and longer time for intubation and repositioning. Moreover, a lateral position is needed and more surgical manipulations are conducted on the airway during thoracic surgery. Thus, more contact and friction between the DLT and the airway may occur and cause more severe trauma to the airway than with use of other devices. In this study, the intensity of sore throat was similar to the intensity of wound pain in group B, although the intercostal block might have reduced the intensity of wound pain. Known risk factors for postoperative sore throat and hoarseness include female gender, smoking, intubating conditions, duration of intubation, type of surgery, coughing or bucking during surgery, oral suction, and high pressure of the cuff.7–10 These risk factors were similar between the 2 groups in this study. Thus, the differences between the DLTs were considered to affect the incidence and intensity of postoperative sore throat. The reason for the significantly lower incidence and intensity of postoperative sore throat in group S than in group Table 4. The Severity of Wound Pain, Total Amount of PCA Infused, and Frequency of Additional Analgesics
DISCUSSION
The authors evaluated whether the type of DLT affected the incidence of postoperative sore throat and hoarseness. Use of a silicon DLT (Silbroncho) compared with a PVC DLT (Broncho-Cath) significantly reduced the incidence of sore throat at 1 hour and 24 hours after DLT extubation. In addition, there was a significant difference in the intensity of postoperative sore throat throughout the 24-hour period after extubation. DLT is the most frequently used airway device in thoracic surgery. However, several reports have indicated that the use of a DLT increases the incidence and the intensity of postoperative sore throat and hoarseness compared with use of a single-lumen tube.3,6 A DLT has a larger diameter with a
Severity of wound pain; VAS 1 h after DLT extubation 24 h after DLT extubation Total amount of PCA infused; mL 1 h after DLT extubation 24 h after DLT extubation Additional analgesics; 0/ 1/ 2 0-1 h after DLT extubation 1-24 h after DLT extubation
Group B
Group S
(n ¼ 30)
(n ¼ 30)
p Value
5.1 (1.0) 3.1 (0.7)
5.1 (0.9) 2.8 (0.7)
0.792 0.162
4.7 (0.7) 45.5 (4.1)
4.6 (0.7) 45.8 (3.6)
0.458 0.741
20/ 10/ 0 9/ 13/ 8
18/ 12 /0 10/ 13/ 7
0.592 0.942
NOTE. Values are expressed as number or mean (SD). Abbreviations: DLT, double-lumen endobronchial tube; PCA, patient-controlled analgesia; SD, standard deviation; VAS, visual analog scale.
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B might be explained as follows: First, the softer texture of the silicon DLT may reduce friction and irritation between the DLT and airway. Second, a silicon DLT has a more flexible distal tip and lesser curvature of the endobronchial lumen; these factors may reduce trauma during intubation and extubation. Third, the shorter endobronchial lumen balloon of the silicon DLT may reduce airway damage due to less contact. Finally, the more flexible stylet of the silicon DLT might reduce resistance to the airway during intubation. Interestingly, the outer diameter of a silicon DLT is about 1 mm greater than that of a PVC DLT of the same French value (11.0 v 10.1 mm in 35 Fr, 11.5 v 10.6 mm in 37 Fr). One study showed that a smaller endotracheal tube was associated with a lower incidence of postoperative sore throat in female patients.11 However, the use of a silicon DLT with larger diameter actually reduced the incidence of postoperative sore throat in the present study. Because the other factors associated with postoperative sore throat were comparable between the 2 groups, the type of DLT was thought to have been a determinant of the different incidences of postoperative sore throat in this study. The difference in outer diameter between silicon DLTs and PVC DLTs may be too small to affect the incidence of postoperative sore throat. Patients with airway problems were excluded, and the size of the DLT was determined by measuring the left main bronchial diameter on CT. Therefore, there were no anatomic problems associated with advancement of the DLT through the vocal cords. However, severe resistance during intubation was felt in 4 patients using the PVC DLT and in 1 patient using the silicon DLT. The DLTs were lubricated with only distilled water in this study, and there may have been friction between the DLT and the airway. This friction might have been felt as resistance during advancement of the DLT through the vocal cords. The difference in the DLT material might have induced the different incidences of severe resistance, although the differences were not statistically significant. The changes in the incidence of postoperative sore throat over time in this study were different from previous reports.3,12,13 The greatest occurrence of postoperative sore throat was at 24 hours after extubation in previous reports but at 1 hour after extubation in the present study. One possible explanation for this difference was the use of ketoracin for PCA in the present study. Inflammatory change in the airway is a mechanism of postoperative sore throat, and some reports indicated that the use of anti-inflammatory agents reduced the incidence of postoperative sore throat compared with that in a control group.12,13 However, the agents were administered only before or during surgery in these reports and the incidence of
postoperative sore throat increased until 24 hours after extubation in all groups. Ketoracin has an anti-inflammatory effect and PCA was administered for at least 24 hours after surgery in the present study. Thus, the anti-inflammatory activity was continuous and may have reduced the incidence of postoperative sore throat consistently for 24 hours after extubation. Unlike sore throat, the incidence of hoarseness was not significantly different between the 2 groups. A previous study reported that hoarseness after tracheal intubation was related to the duration of intubation, not to other factors associated with the process of intubation.14 In the present study, no significant difference was observed in the duration of intubation between the 2 groups. Moreover, the average size of the DLT in the 2 groups was similar, and one experienced anesthesiologist conducted the intubations and extubations in all patients after full relaxation was confirmed. These factors might explain the comparable incidence of hoarseness in both groups. The cost of silicon DLTs differs from one country to another. In the authorsʼ country, the cost of the 2 types of DLTs is identical. In the United States, a silicon DLT costs more than twice as much as a PVC DLT. Therefore, anesthesiologists must consider the factor of cost and select the proper type of DLT depending on the situation. Some limitations to this study should be addressed. First, the anesthesiologist who conducted all intubations and extubations was not blinded. The intubation was performed after full relaxation was confirmed, and the size of the DLT was similar between the 2 groups. However, the anesthesiologist was aware of the randomization code and might have performed more careful intubation using the silicon DLT. Therefore, the nonblinding of the anesthesiologist might have been a bias, although minor. Second, the anesthesiologist was experienced, which may have limited the generalizability of this study because less experienced anesthesiologists have greater difficulty using a DLT. Third, airway damage was evaluated by patient subjective assessment; therefore, interindividual variation might have been present. CONCLUSION
The use of a silicon DLT (Silbroncho) was associated with a lower incidence and intensity of sore throat throughout the 24hour period after extubation than was a PVC DLT (BronchoCath), but it did not decrease the incidence of hoarseness at 1 hour and 24 hours after extubation. The use of silicon DLTs results in a lower incidence of postoperative sore throat than does the use of PVC DLTs.
REFERENCES 1. Christensen AM, Willemoes-Larsen H, Lundby L, et al: Postoperative throat complaints after tracheal intubation. Br J Anaesth 73:786-787, 1994 2. Mandøe H, Nikolajsen L, Lintrup U, et al: Sore throat after endotracheal intubation. Anesth Analg 74:897-900, 1992 3. Knoll H, Ziegeler S, Schreiber JU, et al: Airway injuries after onelung ventilation: A comparison between double-lumen tube and endobronchial blocker: a randomized, prospective, controlled trial. Anesthesiology 105: 471-447, 2006 4. Burton NA, Watson DC, Brodsky JB, et al: Advantages of a new polyvinyl chloride double-lumen tube in thoracic surgery. Ann Thorac Surg 36:78-84, 1983
5. Chow MY, Liam BL, Thng CH, et al: Predicting the size of a doublelumen endobronchial tube using computed tomographic scan measurements of the left main bronchus diameter. Anesth Analg 88:302-305, 1999 6. Zhong T, Wang W, Chen J, et al: Sore throat or hoarse voice with bronchial blockers or double-lumen tubes for lung isolation: A randomised, prospective trial. Anaesth Intensive Care 37: 441-446, 2009 7. McHardy FE, Chung F: Postoperative sore throat: Cause, prevention and treatment. Anaesthesia 54:444-453, 1999 8. Higgins PP, Chung F, Mezei G: Postoperative sore throat after ambulatory surgery. Br J Anaesth 88:582-584, 2002
COMPARISON OF DOUBLE-LUMEN ENDOBRONCHIAL TUBES
9. Mencke T, Echternach M, Kleinschmidt S, et al: Laryngeal morbidity and quality of tracheal intubation: A randomized controlled trial. Anesthesiology 98:1049-1056, 2003 10. Biro P, Seifert B, Pasch T: Complaints of sore throat after tracheal intubation: A prospective evaluation. Eur J Anaesthesiol 22:307-311, 2005 11. Jaensson M, Olowsson LL, Nilsson U: Endotracheal tube size and sore throat following surgery: A randomized-controlled study. Acta Anaesthesiol Scand 54:147-153, 2010
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12. Park SH, Han SH, Do SH, et al: Prophylactic dexamethasone decreases the incidence of sore throat and hoarseness after tracheal extubation with a double-lumen endobronchial tube. Anesth Analg 107:1814-1818, 2008 13. Bagchi D, Mandal MC, Das S, et al: Efficacy of intravenous dexamethasone to reduce incidence of postoperative sore throat: A prospective randomized controlled trial. J Anaesthesiol Clin Pharmacol 28:477-480, 2012 14. Lesser TH, Lesser PJ: Laryngeal trauma vs length of intubation. J Laryngol Otol 101:1165-1167, 1987
Measurements and Main Results: The incidence of sore throat and hoarseness was evaluated at 1 hour and 24 hours after DLT extubation. The intensity of sore throat was assessed by visual analog scale (VAS o 0-10) at 1, 2, 4, 12, and 24 hours after DLT extubation. The incidence of sore throat was significantly lower in group S compared with that in group B at 1 h (30% v 66.7%, p ¼ 0.018) and 24 hours (10% v 43.3%, p ¼ 0.014). No significant difference was observed in the incidence of hoarseness between the 2 groups. The VAS scores for sore throat in group B were significantly higher than those in group S throughout the study (p o 0.05). Conclusions: The use of silicon DLTs resulted in a lower incidence of postoperative sore throat than did the use of PVC DLTs. & 2014 Elsevier Inc. All rights reserved.
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recent respiratory infection (o1 month), prior treatment with steroid or opioid, and a history of disease or surgery on the oral cavity or pharynx. Patients were randomized into the following 2 groups: The Bronchocath group (group B, n ¼ 30) and the Silbroncho group (group S, n ¼ 30). The group allocation was concealed in opaque envelopes that were opened by a staff anesthesiologist immediately before induction of anesthesia. After identifying the randomization code, the anesthesiologist prepared the left-sided DLT according to the group allocation and conducted the entire course of anesthesia, including intubations in all patients and evaluation of parameters associated with intubation. Another anesthesiologist, who was blinded to the group allocation, evaluated and recorded all perioperative parameters except those associated with intubation. The same surgeon conducted all surgeries using the same surgical method. The patients and the surgeon in charge were blinded to the group allocation for the duration of the study. Premedication was omitted, and routine monitoring was performed after arrival in the operating room. Anesthesia was induced with 2 mg/kg of propofol and 0.8 mg/kg of rocuronium. Endotracheal intubation was performed after loss of all 4 twitches of train-of-four stimulation on the ulnar nerve. DLTs were lubricated with distilled water. A direct laryngoscopy was performed using a standard 3 or 4 Macintosh metal blade. The size of the DLT was determined by measuring the left main bronchial diameter on chest computed tomography (CT): 32 Fr for diameter o10 mm, 35 Fr for 10 mm r diameter o 11 mm, and 37 Fr for 11 mm r diameter o 12 mm.5 The stylet was removed immediately after the tip of the endobronchial lumen passed the vocal cord. The position of the DLT was adjusted with fiberoptic bronchoscopy (LF-GP; Olympus, Tokyo, Japan) immediately after intubation and after turning
OSTOPERATIVE SORE THROAT and hoarseness are common complications related to endotracheal intubation and occur in 6.9%-90% of patients.1,2 A double-lumen endobronchial tube (DLT) is the type most widely used for one-lung ventilation to improve the surgical field during thoracic surgery. The larger outer diameter of a DLT compared with an endotracheal tube increases the incidence of postoperative sore throat and hoarseness.3 Two types of material are used to manufacture DLTs: Polyvinylchloride (PVC) and silicon. PVC DLTs (BronchoCath; Mallinckrodt, Hazelwood, MO) and silicon DLTs (Silbroncho; Fugi, Tokyo, Japan) not only differ in material, but also subtly differ in structure. The Silbroncho has a softer body and a more flexible tip on the endobronchial lumen with less curvature. Burton et al reported that use of the softer and more flexible PVC DLT with a gentle distal curve structure decreased complications, such as unsuccessful and difficult intubation, tube dislodgement, unsatisfactory deflation, tube malpositioning, and hypoxemia, compared with use of the rubber DLT.4 Similarly, it was hypothesized for the present study that the use of a silicon DLT would reduce complications from airway irritation during intubation compared with that of the PVC DLT. This study was conducted to determine whether the incidence of postoperative sore throat and hoarseness differed between PVC DLTs and silicon DLTs. METHODS This study was a prospective, single-blind, balanced (1:1), randomized controlled trial. No changes to the design or protocol were made during the course of the study. This study was approved by the institutional review board of the hospital (No.: KC12EISI0132) and registered at the Clinical Research Information Service of the Republic of Korea (No.: KCT0000676). Informed consent was obtained from all study subjects. Sixty patients with ASA class I or II, aged 20-65 years, and scheduled for elective video-assisted thoracoscopic pulmonary lobectomy were enrolled. Exclusion criteria included pre-existing sore throat and hoarseness, known difficult intubation, mouth opening o3.5 cm, Mallampatti score of 3 or 4, Cormack score of 3 or 4,
KEY WORDS: intubation, postoperative complications, sore throat, hoarseness, double lumen tubes, thoracic anesthesia
From the Department of Anesthesiology, The Catholic University of Korea, Seoul St. Maryʼs Hospital, Seoul, Korea. Address reprint requests to Wonjung Hwang, MD, Department of Anesthesiology, The Catholic University of Korea, Seoul St. Maryʼs Hospital, Seoul, Korea, 202 Banpo-Daero, Seocho-gu, Seoul 137-701, Korea. E-mail: [email protected] © 2014 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2014.05.028
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the patient to the lateral position. The pressures of both tracheal and bronchial cuffs were monitored with a noninvasive manometer (ControlInflator; VBM, Sulz, Germany) every 20 minutes and maintained at o20 cmH2O during anesthesia. Anesthesia was maintained with propofol and remifentanil by a target-controlled infusion (Orchestra Base Primea; Fresenius Vial, Grenoble, France). Muscle relaxation was achieved with a 5 μg/kg/min atracurium infusion during the course of surgery to prevent coughing or bucking. Mechanical ventilation was controlled to maintain normocarbia with an inspired oxygen concentration of 100%. The infusion of muscle relaxant was discontinued beginning with surgical field irrigation. The intercostal block was performed by the surgeon before wound closure in all patients. Neuromuscular block was reversed with 0.4 mg of glycopyrrolate and 10 mg of pyridostigmine. At the end of surgery, the train-of-four ratio was measured, and the patients were extubated. Oropharyngeal suction was performed with a 14-Fr soft catheter under direct vision. Intravenous patientcontrolled analgesia (PCA) infusion was initiated after extubation. The PCA consisted of 10 mg/mL of fentanyl and 1.2 mg/mL of ketoracin in normal saline at a continuous infusion rate of 1 mL/hour with a 1-mL bolus and a lockout time of 10 minutes. When the patient suffered from wound pain of severity 45 on a 10-cm visual analog scale (VAS, 0-10: Where 0 means the absence of pain and 10 represents the worst pain imaginable), 25 mg of meperidine were injected intravenously. The primary outcome measure was the incidence of sore throat, and the secondary outcome measure was the incidence of hoarseness recorded at 1 hour and 24 hours after DLT extubation. Postoperative sore throat was defined as pain at the larynx or pharynx, and hoarseness was defined as a harsh or strained voice. In addition, the intensity of sore throat was assessed by the VAS at 1, 2, 4, 12, and 24 hours after DLT extubation. The severity of wound pain assessed by VAS, total volume of PCA infused, and frequency of additional analgesic were recorded at 1 hour and 24 hours after DLT extubation. Parameters associated with DLT intubation also were recorded: Cormack and Lehane score, resistance to DLT insertion classified into none/mild/ severe, the number of intubation attempts (advances of DLT through vocal cord), the time to complete successful DLT intubation from the beginning of laryngoscopy, the number of DLT repositionings, and the duration of DLT intubation. No changes to outcome assessments were made during the trial. In a pilot study conducted with 18 patients, the incidence of sore throat was 60% after PVC DLT intubation and 20% after silicon DLT intubation. To obtain an 80% chance of finding a 67% decrease in the incidence of sore throat (60%-20%) at 1 hour and 24 hours after extubation with α ¼ 0.025 (two-tailed), 24 patients were required for each group. Taking potential dropouts into consideration, 30 patients were included in each group. Data are presented as mean ⫾ standard deviation or absolute value. According to an analysis of distribution, Student’s t test or the MannWhitney U-test was used to compare between-group differences in age, height, weight, time to complete intubation and duration of intubation,
Table 2. Variables Associated With Tracheal Intubation
Size of DLT (Fr), 37/ 35 Cormack and Lehane score, 1/2 Resistance to DLT insertion, none/ mild/ severe Number of intubation attempts, 1/2 Time for complete DLT intubation, sec Number of DLT repositioning, 0/1 Duration of DLT intubation, min
Group B
Group S
p
(n ¼ 30)
(n ¼ 30)
Value
17/13 25/5 18/8/4
13/17 22/8 14/15/1
0.302 0.431 0.109
26/4 12.2 (6.2)
27/3 12.5 (6.0)
1.000 0.842
21/9 22/8 0.774 193.1 (80.0) 172.8 (45.2) 0.231
NOTE. Values are expressed as number or mean (SD). Abbreviations: DLT, double-lumen endobronchial tube; SD, standard deviation.
severity of wound pain, and total volume of PCA infused. Fisher’s exact test was used to compare other demographic data, the Cormack and Lehane score, resistance to DLT insertion, the number of intubation trials, the number of times the DLT was repositioned, the frequency of additional analgesics administered, and the incidence of sore throat and hoarseness. The intensity of sore throat was compared by repeated-measures analysis of variance and the unpaired t test with Bonferroni correction for multiple comparisons if any significant difference was found between groups. No interim analyses were performed. SPSS software for Windows ver. 15.0 (SPSS Inc., Chicago, IL) was used for the analysis. All p values o0.05 were considered to indicate statistical significance. RESULTS
Sixty patients were assessed for eligibility, and all patients were included. Thirty patients each were randomized to groups B and S. No patient was excluded during the study due to failed intubation. All data obtained from the 60 patients were analyzed. Demographic data, including history of smoking, are shown in Table 1. No significant differences were observed between the 2 groups for the demographic data. Variables associated with tracheal intubation are listed in Table 2. The Cormack and Lehane score, resistance to DLT insertion, number of intubation attempts, time to complete DLT intubation, number of DLT repositionings, and duration of DLT intubation were comparable in both groups. The incidence of sore throat was significantly lower in group S than in group B at 1 hour and 24 hours (Table 3). Nine patients (30%) in group S had sore throat at 1 hour after DLT extubation, whereas 20 patients (66.7%) in group B had sore throat (p ¼ 0.018). At 24 hours after DLT extubation, the incidence of sore throat decreased from 1 hour after DLT Table 3. Incidence of Postoperative Sore Throat and Hoarseness
Table 1. Patient Characteristics Characteristics
Age, yr Sex, M/F Height, cm Weight, kg ASA physical status, I/II Smoking, Y/N
Group B (n ¼ 30)
Group S (n ¼ 30)
p Value
61.5 (5.6) 17/13 161.0 (9.3) 63.5 (10.5) 6/24 14/16
60.5 (8.5) 13/17 158.1 (8.7) 58.5 (9.9) 4/26 13/17
0.568 0.302 0.217 0.065 0.731 0.602
NOTE. Values are number or mean (SD). Abbreviations: ASA, American Society of Anesthesiologists; F, female; M, male; N, no; SD, standard deviation; Y, yes.
Group B
Group S
(n ¼ 30)
(n ¼ 30)
p Value
(66.7%) (26.7%)
9 (30%) 4 (13.3%)
0.018* 0.333
(43.3%) (3.3%)
3 (10%) 1 (3.3%)
0.014* 1.0
1 h after DLT extubation Sore throat 20 Hoarseness 8 24 h after DLT extubation Sore throat 13 Hoarseness 1
NOTE. Values are expressed as number (proportion). Abbreviation: DLT, double-lumen endobronchial tube. * p values were adjusted using Bonferroni correction.
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COMPARISON OF DOUBLE-LUMEN ENDOBRONCHIAL TUBES
Fig 1. Intensity of sore throat after double-lumen endobronchial tube extubation; *p o 0.05 compared with group B. Abbreviation: VAS, visual analog scale.
extubation in each group. However, 3 patients (10%) presented with sore throat in group S compared with 13 patients (43.3%) in group B (p ¼ 0.014). Fig 1 shows the intensity of sore throat as assessed by the VAS score. The VAS scores decreased over time in both groups; however, the VAS scores in group B were significantly higher than those in group S throughout the study. The VAS scores were 3.43 ⫾ 2.57 in group B vs. 1.00 ⫾ 1.62 in group S (p o 0.001) at 1 hour after DLT extubation and 1.40 ⫾ 1.73 in group B versus 0.20 ⫾ 0.66 in group S (p ¼ 0.005) at 24 hours after DLT extubation. The severity of wound pain, total volume of PCA infused, and frequency of additional analgesics were not different between the 2 groups (Table 4). The intensity of sore throat and the severity of wound pain were comparable in patients with sore throat in group B; the VAS score of sore throat was 5.15 ⫾ 0.88 and that of wound pain was 5.00 ⫾ 1.08 at 1 hour (n ¼ 20, p ¼ 0.666). The VAS score of sore throat was 3.23 ⫾ 0.93 and that of wound pain was 3.00 ⫾ 0.71 at 24 hours (n ¼ 13, p ¼ 0.534). The incidence of hoarseness also decreased over time but was not significantly different between the 2 groups (Table 3).
curved endobronchial lumen and needs more frequent manipulation and longer time for intubation and repositioning. Moreover, a lateral position is needed and more surgical manipulations are conducted on the airway during thoracic surgery. Thus, more contact and friction between the DLT and the airway may occur and cause more severe trauma to the airway than with use of other devices. In this study, the intensity of sore throat was similar to the intensity of wound pain in group B, although the intercostal block might have reduced the intensity of wound pain. Known risk factors for postoperative sore throat and hoarseness include female gender, smoking, intubating conditions, duration of intubation, type of surgery, coughing or bucking during surgery, oral suction, and high pressure of the cuff.7–10 These risk factors were similar between the 2 groups in this study. Thus, the differences between the DLTs were considered to affect the incidence and intensity of postoperative sore throat. The reason for the significantly lower incidence and intensity of postoperative sore throat in group S than in group Table 4. The Severity of Wound Pain, Total Amount of PCA Infused, and Frequency of Additional Analgesics
DISCUSSION
The authors evaluated whether the type of DLT affected the incidence of postoperative sore throat and hoarseness. Use of a silicon DLT (Silbroncho) compared with a PVC DLT (Broncho-Cath) significantly reduced the incidence of sore throat at 1 hour and 24 hours after DLT extubation. In addition, there was a significant difference in the intensity of postoperative sore throat throughout the 24-hour period after extubation. DLT is the most frequently used airway device in thoracic surgery. However, several reports have indicated that the use of a DLT increases the incidence and the intensity of postoperative sore throat and hoarseness compared with use of a single-lumen tube.3,6 A DLT has a larger diameter with a
Severity of wound pain; VAS 1 h after DLT extubation 24 h after DLT extubation Total amount of PCA infused; mL 1 h after DLT extubation 24 h after DLT extubation Additional analgesics; 0/ 1/ 2 0-1 h after DLT extubation 1-24 h after DLT extubation
Group B
Group S
(n ¼ 30)
(n ¼ 30)
p Value
5.1 (1.0) 3.1 (0.7)
5.1 (0.9) 2.8 (0.7)
0.792 0.162
4.7 (0.7) 45.5 (4.1)
4.6 (0.7) 45.8 (3.6)
0.458 0.741
20/ 10/ 0 9/ 13/ 8
18/ 12 /0 10/ 13/ 7
0.592 0.942
NOTE. Values are expressed as number or mean (SD). Abbreviations: DLT, double-lumen endobronchial tube; PCA, patient-controlled analgesia; SD, standard deviation; VAS, visual analog scale.
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B might be explained as follows: First, the softer texture of the silicon DLT may reduce friction and irritation between the DLT and airway. Second, a silicon DLT has a more flexible distal tip and lesser curvature of the endobronchial lumen; these factors may reduce trauma during intubation and extubation. Third, the shorter endobronchial lumen balloon of the silicon DLT may reduce airway damage due to less contact. Finally, the more flexible stylet of the silicon DLT might reduce resistance to the airway during intubation. Interestingly, the outer diameter of a silicon DLT is about 1 mm greater than that of a PVC DLT of the same French value (11.0 v 10.1 mm in 35 Fr, 11.5 v 10.6 mm in 37 Fr). One study showed that a smaller endotracheal tube was associated with a lower incidence of postoperative sore throat in female patients.11 However, the use of a silicon DLT with larger diameter actually reduced the incidence of postoperative sore throat in the present study. Because the other factors associated with postoperative sore throat were comparable between the 2 groups, the type of DLT was thought to have been a determinant of the different incidences of postoperative sore throat in this study. The difference in outer diameter between silicon DLTs and PVC DLTs may be too small to affect the incidence of postoperative sore throat. Patients with airway problems were excluded, and the size of the DLT was determined by measuring the left main bronchial diameter on CT. Therefore, there were no anatomic problems associated with advancement of the DLT through the vocal cords. However, severe resistance during intubation was felt in 4 patients using the PVC DLT and in 1 patient using the silicon DLT. The DLTs were lubricated with only distilled water in this study, and there may have been friction between the DLT and the airway. This friction might have been felt as resistance during advancement of the DLT through the vocal cords. The difference in the DLT material might have induced the different incidences of severe resistance, although the differences were not statistically significant. The changes in the incidence of postoperative sore throat over time in this study were different from previous reports.3,12,13 The greatest occurrence of postoperative sore throat was at 24 hours after extubation in previous reports but at 1 hour after extubation in the present study. One possible explanation for this difference was the use of ketoracin for PCA in the present study. Inflammatory change in the airway is a mechanism of postoperative sore throat, and some reports indicated that the use of anti-inflammatory agents reduced the incidence of postoperative sore throat compared with that in a control group.12,13 However, the agents were administered only before or during surgery in these reports and the incidence of
postoperative sore throat increased until 24 hours after extubation in all groups. Ketoracin has an anti-inflammatory effect and PCA was administered for at least 24 hours after surgery in the present study. Thus, the anti-inflammatory activity was continuous and may have reduced the incidence of postoperative sore throat consistently for 24 hours after extubation. Unlike sore throat, the incidence of hoarseness was not significantly different between the 2 groups. A previous study reported that hoarseness after tracheal intubation was related to the duration of intubation, not to other factors associated with the process of intubation.14 In the present study, no significant difference was observed in the duration of intubation between the 2 groups. Moreover, the average size of the DLT in the 2 groups was similar, and one experienced anesthesiologist conducted the intubations and extubations in all patients after full relaxation was confirmed. These factors might explain the comparable incidence of hoarseness in both groups. The cost of silicon DLTs differs from one country to another. In the authorsʼ country, the cost of the 2 types of DLTs is identical. In the United States, a silicon DLT costs more than twice as much as a PVC DLT. Therefore, anesthesiologists must consider the factor of cost and select the proper type of DLT depending on the situation. Some limitations to this study should be addressed. First, the anesthesiologist who conducted all intubations and extubations was not blinded. The intubation was performed after full relaxation was confirmed, and the size of the DLT was similar between the 2 groups. However, the anesthesiologist was aware of the randomization code and might have performed more careful intubation using the silicon DLT. Therefore, the nonblinding of the anesthesiologist might have been a bias, although minor. Second, the anesthesiologist was experienced, which may have limited the generalizability of this study because less experienced anesthesiologists have greater difficulty using a DLT. Third, airway damage was evaluated by patient subjective assessment; therefore, interindividual variation might have been present. CONCLUSION
The use of a silicon DLT (Silbroncho) was associated with a lower incidence and intensity of sore throat throughout the 24hour period after extubation than was a PVC DLT (BronchoCath), but it did not decrease the incidence of hoarseness at 1 hour and 24 hours after extubation. The use of silicon DLTs results in a lower incidence of postoperative sore throat than does the use of PVC DLTs.
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5. Chow MY, Liam BL, Thng CH, et al: Predicting the size of a doublelumen endobronchial tube using computed tomographic scan measurements of the left main bronchus diameter. Anesth Analg 88:302-305, 1999 6. Zhong T, Wang W, Chen J, et al: Sore throat or hoarse voice with bronchial blockers or double-lumen tubes for lung isolation: A randomised, prospective trial. Anaesth Intensive Care 37: 441-446, 2009 7. McHardy FE, Chung F: Postoperative sore throat: Cause, prevention and treatment. Anaesthesia 54:444-453, 1999 8. Higgins PP, Chung F, Mezei G: Postoperative sore throat after ambulatory surgery. Br J Anaesth 88:582-584, 2002
COMPARISON OF DOUBLE-LUMEN ENDOBRONCHIAL TUBES
9. Mencke T, Echternach M, Kleinschmidt S, et al: Laryngeal morbidity and quality of tracheal intubation: A randomized controlled trial. Anesthesiology 98:1049-1056, 2003 10. Biro P, Seifert B, Pasch T: Complaints of sore throat after tracheal intubation: A prospective evaluation. Eur J Anaesthesiol 22:307-311, 2005 11. Jaensson M, Olowsson LL, Nilsson U: Endotracheal tube size and sore throat following surgery: A randomized-controlled study. Acta Anaesthesiol Scand 54:147-153, 2010
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12. Park SH, Han SH, Do SH, et al: Prophylactic dexamethasone decreases the incidence of sore throat and hoarseness after tracheal extubation with a double-lumen endobronchial tube. Anesth Analg 107:1814-1818, 2008 13. Bagchi D, Mandal MC, Das S, et al: Efficacy of intravenous dexamethasone to reduce incidence of postoperative sore throat: A prospective randomized controlled trial. J Anaesthesiol Clin Pharmacol 28:477-480, 2012 14. Lesser TH, Lesser PJ: Laryngeal trauma vs length of intubation. J Laryngol Otol 101:1165-1167, 1987
