There was a positive correlation between the intensity of sore throat and the duration of anaesthesia (Spearman's r = 0.12; P = 0.03) and a negative correlation with the lowest SPO2 during extubation (r = −0.30; P < 0.001). There were positive correlations between the duration of sore throat and the duration of anaesthesia (r = 0.16; P = 0.004), the number of postoperative vomiting episodes (r = 0.13; P = 0.02) and the size of the ETT for male (r = 0.34; P = 0.001) and for female (r = 0.14; P = 0.044). There was a negative correlation between the duration of complaints and the lowest SPO2 during extubation (r = −0.36; P < 0.001).
There was no correlation between the incidence of sore throat and the professional grade of the intubator. Therapies for sore throat became necessary, when the intubation had been accomplished by qualified nurses in 8% (from n = 101), with medical doctors in training in 7.3% (from n = 493) and with anaesthesia specialists in 9.5% (from n = 190). No correlation could be determined between the intubators experience in months and the incidence or intensity of sore throat. Medication was only needed by 64 patients (7.9%), but significantly more of these were female (P < 0.001). Furthermore, treatment for sore throat has been associated with the occurrence of postoperative nausea (12% vs. 5.4%; P = 0.001).
With gradual logistic regression of the univariate variables, the following seven characteristics have been proven as significantly associated with postoperative throat complaints: female gender (odds ratio, OR 1.66; P = 0.003), visible bloodstain on the ETT after extubation (OR 4.81; P < 0.001), natural set of teeth (OR 0.46; P < 0.001), pre-existing respiratory tract disease (OR 3.12; P = 0.02), lower age group (by year OR 0.98; P < 0.001), duration of anaesthesia (OR 1.27; P < 0.001) and postoperative vomiting (per vomiting episode OR 0.29; P < 0.001).
Our incidence of post-intubation throat complaints of approximately 40% lies in the middle of ranges of comparable figures from the literature (14-75%) [2-12]. Out of these 11 investigations, however, nine had been performed with far fewer patients than in our study. The results of those two studies, which had a higher number of cases than ours (n = 1325 and 5264, respectively), were 14.4%  and 45.5% . This shows clearly, that our results lie closely to those in the largest study of Higgins and colleagues, which used a similar technique of questioning. In contrast, Christiansen and colleagues did not purposely specify the questioning concerning sore throat, but merely considered the incoming reports passively, which is known to have a substantial influence on the results . Likewise, our results concerning intensity and duration of sore throat corresponded well with the results found in the literature.
The average pain intensity of 28 ± 12 (including only patients indicating a pain level >0 mm) is in the lower range of the 100 mm scale and the duration of a maximum of two days. Strictly speaking, this is a matter of comfort rather than perioperative morbidity. Nevertheless, there are isolated cases with higher intensity of pain, particularly from substantially longer duration of intubation. In these cases, additional symptoms such as hoarseness or even dysphagia can occasionally be found. In this connection, Jones and colleagues stated that about 3% of intubated patients had complaints lasting longer than 1 week and on laryngoscopy had laryngeal lesions, pharyngeal haematomas or granulomas of the vocal cords .
The aetiology of throat complaints is multi-factorial. With our evaluation using gradual logistic regression, we intended, by using a large study with many different intubators of varying professional experience and without mandating any particular anaesthetic method during the study to identify as many causal factors of postoperative throat complaints as possible.
All authors, who had examined the relevance of gender stated without exception that females are more frequently and strongly affected by intubation-related complaints, [4,5,7,11,17,19,20], which corresponds well with our results. The cause of this, however, is still unclear. In our studies, nausea and vomiting arose more frequently with female which has been confirmed elsewhere [19,20]. Beattie and colleagues examined the influence of the menstrual cycle on postoperative nausea and vomiting following gynaecological laparoscopy . Postoperative nausea and vomiting occurred 2.9 times more often in female who were in the first 8 days of their menstrual cycle. We found that sore throat correlated with postoperative nausea and vomiting (r = 0.21; P < 0.001). The choice of ETT size (8.0 mm for males and 7.5 mm for females) does not fairly fit the actual anatomical and functional conditions [8,22,23]. It needs to be examined separately, whether an ETT with an internal diameter of 7.0 mm is a better alternative for female adults.
Our finding that smoking is increasingly accompanied by a sore throat with a longer duration is not particularly surprising. This, however, cannot be verified from other sources and the two studies which found no relation between these were based only on a small number of cases (n < 200) [7,10]. Persons wearing dentures have more space in the oral cavity and a better view can be achieved during laryngoscopy when the denture is removed. Less force may need to be exerted with the blade. However, it cannot clearly be differentiated whether the throat complaints can be put down to the laryngoscopy alone or additionally to the passage and insertion of the ETT. It is interesting to note that the insertion of temperature sensors into the hypopharynx, even thought they are relatively small and flexible, still makes a contribution to the development of sore throat.
In our study, as well as in other comparative evaluations, cuff pressure was of lesser significance since cuffs of the ‘high-volume/low-pressure’ type were used. In addition, the cuffs were inflated to the minimum volume to prevent a leak up to an airway pressure of 25 mbar. An increase of the cuff pressure which may occur by diffusion of nitrous oxide was not relevant since this gas was not used. We did not apply preventive measures routinely, such as filling of the cuff with lidocaine (instead of air), topical application of local anaesthesia or beclomethasone as recommended by some authors [9,24]. Such measures should be left for special cases only, such as patients having operations on the respiratory tract and those who are professionally dependent on their voice. In particular the choice of a thinner ETT should be considered.
The number of intubation attempts as well as the duration of anaesthesia have both been proven as causative factors for throat complaints, which is in agreement with the results of Kloub  and Rieger and colleagures  and is actually self-explanatory. This, however, has not been confirmed by all authors [3,4,6,18]. The limited correlation between throat complaints and the amount or length of professional experience is probably attributed to the fact that after 1 yr, no substantial improvement in intubation skills can be expected .
The extubation procedure has been considered in none of the comparative investigations. Furthermore, the duration of the extubation procedure and the occurrence of coughing and gagging have not previously been considered. We showed, nevertheless, that a sore throat must be expected alongside a bloodstained ETT during extubation.
Postoperative sore throat is a frequent finding after general anaesthesia with tracheal intubation, which usually is not of vital importance but remains a significant cause for discomfort. Relevant factors associated with throat complaints were female sex, natural dentition, smoking, long anaesthesia duration and postoperative nausea and vomiting. Thus further improvement in patient comfort could be expected by focusing on prevention such as choice of narrower ETTs and better prophylaxis and treatment of postoperative nausea and vomiting.
1. Arndt M, Hofmockel R, Benad G. Sore throat
after use of the laryngeal mask and intubation
. Anaesthesiol Reanim
2. Ayoub CM, Ghobashy A, Koch ME, et al
. Widespread application of topical steroids to decrease sore throat
, hoarseness, and cough after tracheal intubation
. Anesth Analg
3. Bennett MH, Isert PR, Cumming RG. Postoperative sore throat
and hoarseness following tracheal intubation
using air or saline to inflate the cuff - a randomized controlled trial. Anaesth Intens Care
4. Christensen AM, Willemoes-Larsen H, Lundby L, Jakobsen KB. Postoperative throat complaints after tracheal intubation
. Br J Anaesth
5. Hähnel J, Treiber F, Konrad F, et al
. Trachealabdichtung, Spitzenzentrierung und Inzidenz postoperativer Halsbeschwerden. [A comparison of different endotracheal tubes. Tracheal cuff seal, peak centering and the incidence of postoperative sore throat
6. Jones MW, Catling S, Evans E, Green DH, Green JR. Hoarseness after tracheal intubation
7. Kloub R. Sore throat
following tracheal intubation
. Middle East J Anesth
8. Mandoe H, Nikolajsen L, Lintrup U, Jepsen D, Moolgaard J. Sore throat
after endotracheal intubation
. Anesth Analg
9. Navarro RM, Baughman VL. Lidocaine in the endotracheal tube cuff reduces postoperative sore throat
. J Clin Anesth
10. Rieger A, Brunne B, Hass I, et al
. Laryngo-pharyngeal complaints following laryngeal mask airway and endotracheal intubation
. J Clin Anesth
11. Stout DM, Bishop MJ, Dwersteg JF, Cullen BF. Correlation of endotracheal tube size with sore throat
and hoarseness following general anesthesia. Anesthesiology
12. Stratelak PA, White W, Wenzel D. The effect of glycopyrrolate premedication on postoperative sore throat
. J Am Assoc Nurse Anesth
13. Shah MV, Mapleson WW. Sore throat
of the trachea. Br J Anaesth
14. Joh S, Matsuura H, Kotani Y, et al
. Change in tracheal blood flow during endotracheal intubation
. Acta Anaesthesiol Scand
15. Klemola U-M, Saarnivaara L, Yrjölä H. Post-operative sore throat
: effect of lignocaine jelly and spray with endotracheal intubation
. Eur J Anaesth
16. Nordin U, Lindholm CE, Wolgast M. Blood flow in the rabbit tracheal mucosa under normal conditions and under the influence of tracheal intubation
. Acta Anaesthesiol Scand
17. Higgins PP, Chung F, Mezei G. Postoperative sore throat
after ambulatory surgery. Br J Anaesth
18. Harding CJ, McVey FK. Interview method affects incidence of postoperative sore throat
19. Jensen PJ, Hommelgaard P, Sondergaard P, Eriksen S. Sore throat
after operation: influence of tracheal intubation
, intracuff pressure and type of cuff. Br J Anaesth
20. Myles PS, Hunt JO, Moloney JT. Postoperative minor complications
. Comparison between men and women. Anaesthesia
21. Beattie WS, Lindblad T, Buckley DN, Forrest JB. Menstruation increases the risk of nausea and vomiting after laparoscopy. A prospective randomized study. Anesthesiology
22. Lipp M, Brandt L, Daubländer M, Peter R, Bärz L. Häufigkeit und Ausprägung von Halsbeschwerden nach Allgemeinanaesthesien bei Einsatz verschiedener Endotrachealtuben. [Frequency and severity of throat complaints following general anesthesia with the insertion of various endotracheal tubes.] Anaesthesist
23. McHardy FE, Chung F. Postoperative sore throat
: cause, prevention and treatment. Anaesthesia
24. El Hakim M. Beclomethasone prevents postoperative sore throat
. Acta Anaesthesiol Scand
25. Monroe MC, Gravenstein N, Saga-Rumley S. Postoperative sore throat
: effect of oropharyngeal airway in orotracheally intubated patients. Anesth Analg
Keywords:© 2005 European Society of Anaesthesiology
POSTOPERATIVE COMPLICATIONS; sore throat; aetiology; intensity; duration; INTUBATION; INTRATRACHEAL; complications