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Risk Factors for Development of Postoperative Sore Throat and Hoarseness After Endotracheal Intubation in Women: A Secondary Analysis Maria Jaensson, RNA, MSc Anil Gupta, MD, PhD, FRCA Ulrica G. Nilsson, RNA, PhD Postoperative sore throat and hoarseness are common and disturbing complications following endotracheal intubation, and women are more frequently affected by these symptoms. This study explores risk factors associated with postoperative sore throat and hoarseness in women following intubation. In this prospective cross-sectional study, 97 patients undergoing elective ear, nose, and throat surgery or plastic surgery were included. Eight different variables were analyzed to detect possible associations for the development of postoperative sore throat or hoarseness. For data analysis, the χ2

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n an anesthetized patient, the free airway is of vital importance, and this is often maintained by use of an endotracheal tube (ETT). The purpose of an endotracheal intubation is to ensure a secure airway and provide an opportunity for positive pressure ventilation and minimal risk of aspiration.1 If an airway complication occurs, it is usually a consequence of the anesthesia itself.2 Apart from injury to the teeth, the most common complications of endotracheal intubation are postoperative sore throat (POST) and postoperative hoarseness (PH).3-5 The incidence of POST and PH varies in different studies depending on the population under survey. In one previous study, the incidence of POST and PH were found to be 40% and 42%, respectively, in a female population.6 These symptoms are so common that the patients and the anesthesia staff believe that they are a natural consequence of endotracheal intubation.7 Postoperative sore throat is at its peak in the early postoperative period, 2 to 6 hours after extubation,6,8 but the incidence decreases rapidly with time. It can sometimes be long-lasting, and after 96 hours, it has been reported that as many as 11% can have residual symptoms.6 The symptoms of POST or PH are sometimes disturbing, and they are one of several outcome variables associated with patient dissatisfaction.6, 9-11 The cause of POST could be mucosal injury in the trachea7 or vocal cord injury,5 and there are several contributing factors for these injuries. Previously recognized risk factors for POST include female gender,

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test and the odds ratio were used. Three variables were found to be significant risk factors for postoperative sore throat: age greater than 60 years (P = .01), the use of a throat pack (P = .04), and endotracheal tube No. 7.0 (size 7 mm; P = .02). The only risk factor found to be significantly associated with developing hoarseness was an endotracheal cuff pressure below 20 centimeters of water (P = .04). Larger studies are needed to confirm these risk factors. Keywords: Endotracheal intubation, hoarseness, postoperative complications, risk factors, sore throat.

size of the ETT, grade of difficulty in intubation, and duration of surgery.3,4,12 If the ETT cuff is overinflated, it might damage the mucosa and cause POST.13 There is inconsistency in the literature as to the age group that is at greatest risk of developing POST.4,12 In one study, patients in the age group 30 to 39 years were most prone to experience symptoms,4 while in another study,12 patients older than 60 years were at greatest risk. Risk factors associated with PH are ETT size14 and nonoptimal intubation conditions.5,15 To our knowledge, only 2 studies on patients’ preferences for avoiding postoperative symptoms have been published.9,10 In one study, out of 10 adverse outcomes following surgery, avoiding postoperative pain was ranked to be the most important and POST was the sixth most important.9 In the other study, Macario et al10 found that POST was disturbing and ranked eighth out of 10 adverse outcomes. The current study was designed to identify risk factors associated with POST and PH in women following endotracheal intubation. The aim was to add to our knowledge about predictors of poor outcomes in patients undergoing surgery with an ETT, in order to maintain a free airway.

Materials and Methods This was a secondary analysis of prospective, crosssectional data collected from patients previously enrolled in a randomized controlled trial,6 with the aim of assessing the effect of different sizes of ETTs on sore throat and

AANA Journal  August 2012  Vol. 80, No. 4  Special Research Edition S67

hoarseness postoperatively. In that study, the patients were randomly assigned to be intubated with ETT No. 6.0 or No. 7.0 (6.0 or 7.0 mm; Mallinckrodt Hi-Contour, Mallinckrodt Medical, Athlone, Ireland). A power analysis was performed in the same study to detect a difference of 30% between the 2 groups (ETT 6.0 vs 7.0) with a primary endpoint of POST, a significance level of 5%, and a power of 80% (N = 100). Ethics committee approval was obtained from the Ethical Committee in Uppsala, Sweden (reference No. 2008/023), in February 2008. Written, informed consent was given by all 100 consecutively enrolled women undergoing elective plastic surgery or ear, nose, and throat surgery (ENT) at the University Hospital in Orebro, Sweden, from March to December 2008. Inclusion criteria were women at least 18 years of age, ASA physical status 1 or 2, elective surgery in the supine position with expected duration longer than 90 minutes, and successful oral intubation after 1 or 2 attempts. It was also important that the patients had the ability to read and understand Swedish. Patients with an ongoing upper respiratory tract infection were excluded from the study. Other exclusion criteria were surgery performed in the mouth or throat area, anesthesia with rapid sequence induction, and administration of succinylcholine. The anesthesia protocol was standardized according to the routines in the anesthesia department, which included general anesthesia with either total intravenous or inhalation anesthesia using sevoflurane or desflurane. The patients were intubated by either a registered nurse anesthetist or an anesthesiologist. No personnel undergoing anesthesia training were allowed to intubate the patients included in the study. The ETT cuff was inflated with air, and the cuff pressure was monitored continuously. No lubricant or local anesthetic gel was applied on the distal ends of the ETT. No oral airway device was used intraoperatively, and it was only inserted when necessary at the time of extubation. The intraoperative monitoring included noninvasive blood pressure, 3-lead electrocardiography, pulse oximetry, and train-of-four monitoring (Draeger Medical AG & Co, Lübeck, Germany). The patients were normoventilated (Pco2, 5.0-5.5 kPa) using a Primus Draeger ventilator (Draeger Medical AG & Co, Lübeck, Germany). Postoperatively all patients received 1 g of paracetamol 4 times a day. Parecoxib (40 mg), morphine, fentanyl, or alfentanil was administered intravenously until a numeric rating scale less than 3 according to hospital routine. Prophylactic medication was administered if needed for postoperative nausea and vomiting according to hospital routine, as either monotherapy or an appropriate combination of betamethasone, droperidol, and/or ondansetron. For evaluation of POST and PH, 8 independent variables were categorized and analyzed. They were as

follows: age (18-60 vs >60 years), smoking (ie, smoker vs nonsmoker), Mallampati score (I-II vs III-IV), CormackLehane grading (I-II vs III-IV), cuff pressure in centimeters of water (≤ 20 vs >20 cm H2O), duration of anesthesia (≤ 193 vs >193 minutes), use of a throat pack (yes vs no), and ETT size (No. 6.0 vs 7.0). The categorical variables were selected to either confirm earlier recognized risk factors associated with POST: age, smoking status, cuff pressure, or duration of anesthesia; confirm the relation between ETT size and PH; or add to new knowledge. Examples of the latter were whether difficulty in intubation (using Mallampati and/or Cormack-Lehane classification) correlates to POST or PH or whether the use of a throat pack plays a role in the development of postoperative symptoms of sore throat or hoarseness. Mallampati score and Cormack-Lehane grading have been used commonly and are consistently shown to be able to predict a difficult airway.2 During the early postoperative period (1-2 hours) in the postanesthesia care unit, the patients rated POST on a previously reported 4-point scale (0-3) as follows16: 0 = no sore throat, 1 = mild sore throat (less severe than with a common cold), 2 = moderate sore throat (similar to that noted with a common cold), and 3 = severe sore throat (more severe than that associated with a common cold). Postoperative hoarseness was assessed using a binary scale (yes or no). The data were collected by a trained, blinded postoperative care nurse. The dependent variables were considered to be POST and PH. Postoperative sore throat was dichotomized to sore throat (grades 1-3 on the 4-grade scale described previously) and no sore throat (grade 0 on the same scale). Postoperative hoarseness was assessed using a binary scale and categorized as presence or absence of hoarseness. The independent variables previously described were analyzed against the dependent variables (POST and PH) using the χ2 test, and the odds ratio (OR) and confidence interval (CI) were calculated for each significant variable. Parametric statistics (unpaired Student t test) was used for continuous variables. We did not perform a logistic regression analysis because the sample size was considered to be too small. Statistical significance was set to a P value < .05. The statistical software program, SPSS 17.0 for Windows (SPSS Inc, Chicago, Illinois), was used for all statistical analyses.

Results Three patients were excluded from the study. Two women received succinylcholine, which was a protocol violation, and 1 woman postoperatively contracted a viral infection of the upper respiratory tract, making it difficult to differentiate the symptoms of POST from those of a common cold. Thus, 97 women were included in the study. The characteristics of participants are presented in Table 1. There were no statistical differences in use of

S68 AANA Journal  August 2012  Vol. 80, No. 4  Special Research Edition


Characteristic Value Demographic, median (range) Age (y)

47 (18-90)

Weight (kg)

71 (51-116)

Body mass index (kg/m2)

25.8 (17.9-44.2)

Height (cm)

165 (154-182)

Type of surgery, No. Plastic surgery/ENT

78/19

Intraoperative medication, mean dose ± SD Fentanyl/remifentanil (µg) Betamethasone (mg)

224.0 ± 93.0/1.068 ± 822.0 4.20 ± 0.90

Anticholinergics: atropine/glycopyrrolate (mg)

0.44 ± 0.16/0.2 ± 0

Table 1. Characteristics of Participants (N = 97) Abbreviations: ENT, ear, nose, and throat; SD, standard deviation.

opioid (fentanyl or remifentanil), anticholinergics (atropine or glycopyrrolate), or betamethasone between POST vs no POST and PH vs no PH (Table 1). Of the 8 variables evaluated, 3 variables were found to be significantly associated with development of POST. These were age greater than 60 years compared with 18 to 60 years (64% vs 32% [14/22 vs 24/75]; P = .01), ETT size No. 7.0 compared with ETT 6.0 (51% vs 27% [25/49 vs 13/48]; P = .02), and the use of a throat pack compared with no throat pack (64% vs 35% [9/14 vs 29/83]; P = .04), as shown in Table 2. The corresponding odds ratio (OR) for these 3 variables were as follows: age greater than 60 years, OR 3.72; intubation with ETT 7.0, OR 2.80; and use of a throat pack, OR 3.35 (Table 3). No significant association was found between the Mallampati score/Cormack-Lehane grading, duration of anesthesia, or smoking and the risk of developing POST (Table 2) or PH (Table 4). There was no significant association between cuff pressure and POST (Table 2). Cuff pressure below 20 cm H2O was the only factor associated with an increased risk of PH compared with cuff pressure above 20 cm H2O (59% vs 36% [17/29 vs 24/67]; P = .04), as shown in Table 4. The OR was 2.5 when the cuff pressure was below 20 cm H2O compared with above 20 cm H2O (Table 3).

Discussion General anesthesia with endotracheal intubation can result in minor postoperative complications, including sore throat and hoarseness, which are more common in the female population.3,4,12 Although these symptoms may be considered to be minor by some, they are important measures of quality of care. In most cases, the symptoms resolve spontaneously without intervention, but in a few cases, they may persist. When the symptoms do occur, patients perceive them as mild to severe and often discomforting.6 Therefore, identification of risk factors and prevention of these symptoms would add to patient satisfaction.


In the present study, we found that older patients (>60 years) had almost 4 times higher the risk of developing POST, which is similar to the results of a previous study identifying age as a risk factor.12 The reason why older patients are at increased risk of POST is unclear. It is possible that, in women, hormonal changes after menopause may result in dryness of the mucosa in the upper airway, thus making it more susceptible to injury. Injury to the epithelium such as during laryngoscopy and intubation may further damage the dry mucosa and thereby result in POST. This could be supported by the fact that the use of a throat pack on a dry mucosal lining of the laryngopharynx was also a significant risk factor in the development of sore throat in our present study. The use of a throat pack increased the risk of developing sore throat by more than 3 times; this finding is in contrast to previous studies in which the presence of a throat pack was not found to be a risk factor in the development of POST.17,18 Our patients predominantly underwent ENT surgery, in which it is common to use a throat pack to prevent blood from trickling into the stomach and leading to postoperative nausea and vomiting. In view of the contrasting results between Kloub17 and Tay et al18 and the present study, the use of a throat pack should be further analyzed in prospective clinical studies of sore throat after ENT surgery. Not surprisingly, the size of the ETT played an important role in the development of POST, as has been shown in earlier studies.16,19 The risk increased by almost 3 times compared with if a smaller size ETT was used. The reason why women are at greater risk of POST developing is unclear. It has been suggested that there might be a gender difference in reporting adverse outcomes to hospital staff,20 but there may also be anatomical differences in the larynx between men and women. According to Randestad et al,21 the female larynx is narrow, and an ETT size No. 7.0 may not fit, which is consistent with the findings of Koufman et al.22 These authors suggested that the ETT size for both men and


Risk factor group (N = 97)

No POST (n = 59), No. (%)

POST (n = 38), No. (%)

51 (68)

24 (32)

8 (36)

14 (64)

P valuea

Age (y) 18-60 >60

.01

Smoker Yes

11 (61)

7 (39)

No

48 (61)

31 (39)

55 (61)

35 (39)

4 (57)

3 (43)

58 (61)

37 (39)

.98

Cormack-Lehane grade I-II III-IV

.84

Mallampati grade (N = 95) I- II III-IV

NA

NA

Cuff pressure (cm H2O)

≤ 20

15 (50)

15 (50)

>20

44 (66)

23 (34)

.14

Throat pack Not used

54 (65)

29 (35)

5 (36)

9 (64)

No. 7.0

24 (49)

25 (51)

No. 6.0

35 (73)

13 (27)

≤ 193

35 (60)

23 (40)

>193

24 (62)

15 (38)

Used

.04

ETT .02

Duration of anesthesia (min) .91

Table 2. Risk Factors Related to POST

a P values refer to comparison of POST between groups (60 y, smoker vs nonsmoker, Cormack-Lehane grade I-II vs III-IV, etc); analyzed with χ2 test.

Abbreviations: POST, postoperative sore throat; NA, not analyzed; ETT, endotracheal tube.

Dependent variable

Risk factor

P value

OR

95% CI

POST

Age >60 y

.01

3.72

1.38 -10.06

Throat pack

.04

3.35

1.03 -10.94

ETT 7.0 vs 6.0

.02

2.80

1.20 - 6.55

PH

Cuff pressure ≤ 20 cm H2O

.04

2.54

1.04 - 6.19

Table 3. Risk Factors for POST and PH Abbreviations: OR, odds ratio; CI, confidence interval; POST, postoperative sore throat; ETT, endotracheal tube; PH, postoperative hoarseness; and cm H2O, centimeters of water.

women should be reduced to minimize damage to the cricoid ring. Despite these reports, several textbooks suggest that the appropriate size of the ETT is 8.0 to 9.5 for men and 7.0 to 8.5 for women.2,23 Another factor that should be considered is whether the intracuff pressure is important in the development of POST or PH. Some studies have shown that an increase in cuff pressure leads to POST.13,24 However, to our knowledge, no study has examined whether PH is related

to cuff pressure. Surprisingly, and contrary to our belief, we found that a cuff pressure below 20 cm H2O was associated with PH. One possible explanation for this finding could be that the movement of the ETT during controlled ventilation may lead to irritation of the narrowest part of the airway, the vocal cords, thus leading to hoarseness. This is more likely to occur when using an ETT with a low cuff pressure because the tube is probably not fixed in the tracheal lumen. In the present study, all patients



Risk factor group (N = 96)a

No PH (n = 55), No. (%)

PH (n = 41), No. (%)

P valueb

18-60

41 (55)

34 (45)

.33

>60

14 (67)

7 (33)

Yes

8 (44)

10 (56)

No

47 (60)

31 (40)

50 (56)

39 (44)

5 (71)

2 (29)

54 (57)

40 (43)

Age (y)

Smoker .22

Cormack-Lehane grade I-II III-IV

.43

Mallampati grade (N = 94) I- II III-IV

NA

NA

Cuff pressure (cm H2O)

≤ 20

12 (41)

17 (59)

>20

43 (64)

24 (36)

48 (59)

34 (41)

7 (50)

7 (50)

No. 7.0

26 (53)

23 (47)

No. 6.0

29 (62)

18 (38)

≤ 193

32 (55)

26 (45)

>193

23 (61)

15 (39)

.04

Throat pack Not used Used

.55

ETT .39

Duration of anesthesia (min) .60

Table 4. Risk Factors Related to PH

a Data were missing from 1 patient. b P values refer to comparison of PH between groups (60 y, smoker vs nonsmoker, Cormack-Lehane grade I-II vs III-IV, etc); analyzed with χ2 test.

Abbreviations: PH, postoperative hoarseness; NA, not analyzed; ETT, endotracheal tube.

were in the supine position, the ETT was fixed with tape, and no oral airway was used intraoperatively. Although an oral airway may contribute to a more stable fixation, it has also been shown to be associated with worse POST.25 Another factor of importance for the development of POST could be the experience of the person performing the intubation.6 Although instinctively obvious, previous studies have surprisingly not shown that the experience of the intubator is related to POST or PH.3,17 However, in the present study, no trainees were allowed to intubate patients in this study. Other explanations for the association between low cuff pressure and PH need investigation. In view of the fact that difficulty in intubation could also be a risk factor for development of POST, the hypothesis was that higher grades in the Mallampati and the Cormack-Lehane classifications may be associated with the development of POST and PH. However, no such association was found in this study, and there is no evidence in the literature to support this hypothesis.


It is important that scoring systems for assessment of postoperative symptoms are reliable; otherwise, results may be difficult to interpret. The reliability and validity of the pain scale that we used to identify POST can therefore be questioned. Pain, as during a sore throat, is a subjective experience for the patient, and it may be difficult to quantify this symptom. Nevertheless, this scale has been used in several studies on the subject.4,16,18,19,25 A standardized direct questioning was used, which may have a major effect on reporting of POST compared with indirect questioning using open-ended questions.26 During measurement of hoarseness, the binary scale was used, and therefore a grading of the symptom was not possible, which could be considered a drawback of this study. However, the lack of quantification of PH has been an issue in previous studies published on the subject,12,14,15,17,27 including from our own group.6 An alternative to the use of a binary scale for measuring PH is subjective observation or the use of a laryngostroboscope.


The former implies that the same observer assesses the patient preoperatively and postoperatively and remembers the degree of hoarseness, a method that is practically difficult to perform and doubtful methodically.16 A stroboscope has been used in a previous study but may be thought to be an invasive method and may be difficult to justify from an ethical perspective.5 Unfortunately, no easy answers exist for these concerns, but we believe that it is important to be aware of the problems in measuring and quantifying the patients’ symptoms. Although the validity of these scales can be questioned, they have previously been used in several studies and appear to be reliable. There are some limitations in the present study that should be considered. This study includes relatively few patients for identification of risk factors for POST and PH. Previous studies on this subject have included larger patient populations, ranging from 809 to 7,541 patients.3,4,27 However, even in the present study with a small sample size, several risk factors could be identified as significant in predicting POST or PH. In addition, our results in women undergoing ENT and plastic surgery may be difficult to generalize to other types of surgeries and patients, and the predictive factors identified by us in women may not necessarily be transferable to the male population. Therefore, further studies in the male population are needed, as gender differences in the incidence of, and risk factors for, POST and PH have not been fully investigated. Another limitation of this study is that, the assessment of symptoms of POST and PH were made at only a single time point, 1 to 2 hours after extubation. However, these symptoms usually emerge in the early postoperative period and, therefore, early assessment can help the providers to capture patients at risk. Patient-reported outcome measures research is based on knowledge and insight into how the patient perceives different situations. Suffering related to anesthesia care might be decreased with an insight into who is at risk of developing airway symptoms after an endotracheal intubation. To alleviate suffering related to patient care, it is important to have a greater understanding of the patient’s world as well as how care is perceived by the patient.28 In conclusion, we found in women that age over 60 years, the use of a throat pack, and larger size ETT increased the risk of developing a sore throat postoperatively. A lower cuff pressure was the only factor that contributed toward increasing the risk of hoarseness postoperatively. Because this is a secondary analysis, further prospective studies with a larger patient population ought to be performed, with the aim of identifying other risk factors for developing postoperative airway symptoms. REFERENCES 1. Letizia M, O’Leary J, Vodvarka J. Laryngeal edema: perioperative nursing considerations. Medsurg Nurs. 2003;12(2):111-115. 2. Aitkenhead AR, Smith G. The practical conduct of anaesthesia. In:

Textbook of Anaesthesia. 3rd ed. London, England: Churchill Livingstone; 1996:319-333. 3. Biro P, Seifert B, Pasch T. Complaints of sore throat after tracheal intubation: prospective evaluation. Eur J Anaesthesiol. 2005;22(4):307-311. 4. Chen KT, Tzeng JI, Lu CL, et al. Risk factors associated with postoperative sore throat after tracheal intubation: an evaluation in the postanesthetic recovery room. Acta Anaesthesiol Taiwan. 2004;42(1):3-8. 5. Mencke T, Echternach M, Kleinschmidt S, et al. Laryngeal morbidity and quality of tracheal intubation: a randomized controlled trial. Anesthesiology. 2003;98(5):1049-1056. 6. Jaensson M, Olowsson LL, Nilsson U. Endotracheal tube size and sore throat following surgery: a randomized-controlled study. Acta Anaesthesiol Scand. 2010;54(2):147-153. 7. Beebe DS. Complications of tracheal intubation. Semin Anesth Perioperative Med Pain. 2001;20(3):166-172. 8. Hung NK, Wu CT, Chan SM, et al. Effect on postoperative sore throat of spraying the endotracheal tube cuff with benzydamine hydrochloride, 10% lidocaine, and 2% lidocaine. Anesth Analg. 2010; 111(4):882-886. 9. Jenkins K, Grady D, Wong J, Correa R, Armanious S, Chung F. Postoperative recovery: day surgery patients’ preferences. Br J Anaesth. 2001;86(2):272-274. 10. Macario A, Weinger M, Carney S, Kim A. Which clinical anesthesia outcomes are important to avoid? The perspective of patients. Anesth Analg. 1999;89(3):652-658. 11. Philip BK. Patients’ assessment of ambulatory anesthesia and surgery. J Clin Anesth. 1992;4(5):355-358. 12. Ahmed A, Abbasi S, Ghafoor AH, Ishaq M. Postoperative sore throat after elective surgical procedures. J Ayub Med Coll Abbottabad. 2007;19(2):12-14. 13. Combes X, Schauvliege F, Peyrouset O, et al. Intracuff pressure and tracheal morbidity: influence of filling with saline during nitrous oxide anesthesia. Anesthesiology. 2001;95(5):1120-1124. 14. Al-Qahtani AS, Messahel FM. Quality improvement in anesthetic practice—incidence of sore throat after using small endotracheal tube. Middle East J Anesthesiol. 2005;18(1):179-183. 15. Combes X, Andriamifidy L, Dufresne 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(2):276-281. 16. Stout DM, Bishop MJ, Dwersteg JF, Cullen BF. Correlation of endotracheal tube size with sore throat and hoarseness following general anesthesia. Anesthesiology. 1987;67(3):419-421. 17. Kloub R. Sore throat following tracheal intubation. Middle East J Anesthesiol. 2001;16(1):29-40. 18. Tay JY, Tan WK, Chen FG, Koh KF, Ho V. Postoperative sore throat after routine oral surgery: influence of the presence of a pharyngeal pack. Br J Oral Maxillofac Surg. 2002;40(1):60-63. 19. Hisham AN, Roshilla H, Amri N, Aina EN. Post-thyroidectomy sore throat following endotracheal intubation. ANZ J Surg. 2001;71 (11):669-671. 20. Myles PS, Hunt JO, Moloney JT. Postoperative ‘minor’ complications: comparison between men and women. Anaesthesia. 1997;52(4): 300-306. 21. Randestad Å, Lindholm CE, Fabian P. Dimensions of the cricoid cartilage and the trachea. Laryngoscope. 2000;110(11):1957-1961. 22. Koufman JA, Fortson JK, Strong MS. Predictive factors of cricoid ring size in adults in relation to acquired subglottic stenosis. Otolaryngol Head Neck Surg. 1983;91(2):177-182. 23. Henderson J. Airway management in the adult. In: Miller RD. Miller’s Anesthesia. 7th ed. Philadelphia, PA: Churchill Livingstone; 2005:chap 50. 24. Ratnaraj J, Todorov A, McHugh T, Cheng MA, Lauryssen C. Effects of decreasing endotracheal tube cuff pressures during neck retraction for anterior cervical spine surgery. J Neurosurg. 2002;97(2 suppl):176-179. 25. Kyokong O, Charuluxananan S, Muangmingsuk V, Rodanat O, Subornsug K, Punyasang W. Efficacy of chamomile-extract spray for prevention of post-operative sore throat. J Med Assoc Thai. 2002;85(suppl 1):S180-S185.



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AUTHORS Maria Jaensson, RNA, MSc, is a Registered Nurse Anesthetist in the Department of Anesthesiology and Intensive Care at University Hospital in Orebro, Sweden, and a PhD student in the School of Health and Medical Sciences, Orebro University, Orebro, Sweden.


Anil Gupta, MD, PhD, FRCA, is associate professor in the Department of Anesthesiology and Intensive Care, University Hospital in Orebro. Ulrica G. Nilsson, RNA, PhD, is associate professor in the Department of Nursing, Umea University and Center of Health Care Sciences, Orebro County Council, Sweden.

ACKNOWLEDGMENTS The authors thank Lena Lassinantti-Olowsson, RNA, MSc, Department of Anesthesiology and Intensive Care, University Hospital in Orebro, Sweden, for her assistance in data collection. This study was supported by grants from the Center of Health Care Sciences, Orebro County Council, Sweden.
