Abstract
Postoperative sore throat (POST) is the eighth most common side effect in the postoperative period. Though it is considered as a minor side effect, it can lead to significant discomfort for the patient. Increased morbidity due to postoperative sore throat could have a big impact on outcomes with an increased economic burden to the nation. To determine the efficacy of ketamine gargle on a postoperative sore throat, we compared ketamine gargle with a normal saline gargle. Furthermore, we studied their efficacy on postoperative cough and hoarseness of voice. We randomly allocated 60 patients of ASA—I and II into two groups equally in patients posted for middle ear surgeries under general anaesthesia. Patients of the group- K were asked to gargle with 40 mg ketamine mixed with 29 ml normal saline preoperatively. Group- C patients were given 30 ml normal saline to gargle. Airway manipulation in all patients was done by senior anesthesiologists in the operating room. Patients were observed and interviewed at 1 h, 6 h, and 24 h after extubation for postoperative sore throat, cough, and hoarseness of voice. In the control group, the incidence of postoperative sore throat at 1 h, 6 h, and 24 h was 50%, 43.3%, and 36.7% respectively. When we compared the incidence in the ketaminegroup (Group-K) with the control group it showed that they were significantly lower (p-value ≤ 0.05) at all three observation points. On the other hand, ketamine gargle has no significant protective effect on the severity of postoperative sore throat, cough, and hoarseness of voice. Ketamine gargle in this study, showed significantly effective in attenuating postoperative sore throat in patients undergoing tracheal intubation for elective surgeries.
Keywords: Postoperative, sore, throat; Ketamine, gargles
Introduction
Postoperative sore throat (POST) is the eighth most common side effect in the postoperative period [1]. POST could be a significant discomfort for the patient resulting in patient dissatisfaction, bad memories of symptoms, and delayed discharge from the hospital [2]. The incidence rate varies from 21 to 65% [3]. All these results in the poor postoperative outcome and increased economic burden.
Patients’ complaints of ‘sore throat’ include conditions like pharyngitis, laryngitis, tracheitis, dysphagia, hoarseness, and cough [4]. Tracheal intubation can lead to several complications classified into immediate, early, and late ones. Adverse consequences of prolonged intubation are well documented, but pathological changes following routine surgeries under GA with tracheal intubation are mostly ignored [5].
Most of its complications are due to high cuff pressure [6]. High pressure inside the ET tube cuff compresses tracheal mucosa, resulting in blood flow limitation, leading to mucosal inflammation and ulceration [4].
A few factors like female sex, prolonged duration of anesthesia, pre-existing lung disease, larger tracheal tube size have shown more association with POST. Endotracheal intubation without neuromuscular blocking increases the incidence of POST [4].
Due to its high incidence rate and morbidity of patients in postoperative care, several pharmacological and non-pharmacological methods are being tried to prevent POST. Non-pharmacological methods include smaller-sized tubes, lubricating the tube with water-soluble jelly, careful laryngoscopy and ETT placement, intubation after complete relaxation, gentle oropharyngeal suctioning, minimizing intracuff pressure [7], and extubation after total deflation of the cuff. Frequently used pharmacological methods are inhaled corticosteroids, systemic corticosteroids, topical corticosteroids [8], ketamine gargles & nebulization, oral aspirin, intravenous NSAIDs, gargles with azulene sulphonate, topical lidocaine jelly, and magnesium sulfate gargle.
Among these different methods, no single method has been accepted universally due to ambiguity in results. In this study, we compared the efficacy of ketamine gargle with normal saline gargle in attenuating postoperative sore throat in patients undergoing tracheal intubation for general anesthesia posted for elective surgery.
Material and Methodology
Our study was conducted after approval from the institutional ethics committee of Maharshi Markandeshwar Institute of Medical Sciences and Research. It was a randomized, double-blinded prospective study done in the Department of Anesthesiology, Maharshi Markandeshwar Institute of Medical Science and Research. A total of 60 patients of ASA—I and II aged between 18 and 50 years scheduled for ear surgeries under general anaesthesia were taken and randomly allocated into two groups 30 each using sealed, opaque envelope technique. Exclusion criteria included obesity (BMI ≥ 30), smoking, pregnancy, pre-existing respiratory infection, and neurological conditions, cervical spine and neck pathology. Using the opaque sealed envelope technique randomly they were allocated into two groups with 30 patients in each group (Group-K and Group-C).
All allocated patients were evaluated in the ward one day before surgery for a pre-anesthetic checkup. There they were informed about the study and consent for the study was taken.
Patients of the group- K were given 40 mg ketamine with 29 ml normal saline and group-C received 30 ml normal saline to gargle 5 min before shifting the patient to the operating room.
In the operating room, a multipara monitor with non-invasive blood pressure, SpO2, ECG, and EtCO2 were attached. All patients were premedicated with intravenous midazolam (40 µg/kg), 0.2 mg glycopyrrolate and nalbuphine (0.1 mg/kg). After 3 min of preoxygenation when EtO2reached ≥ 90, induction of anesthesia was done with intravenous propofol (2.5 mg/kg). Confirming adequate mask ventilation intravenous succinylcholine (2 mg/kg) was given to achieve neuromuscular block. Male patients with an endotracheal tube of 8 mm and female patients with a 7 mm internal diameter were intubated by a trained anesthesiologist. After cuff inflation, checking bilateral air entry and tubes fixation cuff pressure was checked every hour with AMBU cuff pressure gauge and maintained between 18 and 22 cm of water. Patients were monitored for adequate ventilation, hemodynamic stability, and analgesia.
After completion of the surgery, oropharyngeal gentle suctioning was done. For reversal of residual neuromuscular blockade intravenous neostigmine (0.05 mg/kg) and glycopyrrolate (0.01 mg/kg) were administered. Ensuring complete reversal patients were extubated and shifted to postoperative care unit in head end elevated position with oxygen supplementation.
All patients were monitored and observation findings were noted on the prescribed proforma at 1 h, 6 h, and 24 h after extubation. We used a verbal rating score system for the assessment of sore throat and its severity (Table 1). On this four-point scale, zero represents no sore throat and three indicates severe sore throat.
Table 1.
Verbal rating score system
| Score | Grading | Description |
|---|---|---|
| 0 | No sore throat | No complaint at any time since the operation |
| 1 | Minimal sore throat | The patient answers in the affirmative when asked about the sore throat |
| 2 | Moderate sore throat | The patient complains of sore throat on his/her own |
| 3 | Severe sore throat | The patient is in obvious distress |
All collected data were compiled and statistically analyzed using Statistical package for social science (SPSS) version 20 (IBM, Chicago, USA) to draw relevant conclusions. Qualitative variables will be expressed as proportions in terms of percentage. Quantitative variables were expressed as mean, standard deviation, median and interquartile range. The association of independent and dependent variables was established using the Chi-square test, ANOVA test depending on variables. A p-value < 0.05 were considered significant at a 95% confidence interval.
Results
All patients were followed up at 1 h, 6 h, and 24 h after extubation for assessment. Anesthesia residents responsible for follow-up were unaware of the measures taken to decrease postoperative sore throat. Data from all 120 patients were analyzed.
Demographic variables like age, sex, and BMI were found to be an insignificant effect on a postoperative sore throat. Other variables like Mallampati score, ASA score, number of intubation attempts and mean duration of anesthesia also found insignificant factors for the incidence of POST.
In our study, at 1 h, 6 h, and 24 h 50%, 43.3%, and 36.7% patients reported postoperative sore throat respectively in the control group (group-C) as seen in Table 2. On the other hand, patients of the ketamine group (group- K) reported 23.3%, 16.7%, and 13.3% at the same three observation time. Hence, throughout the observation period ketamine group showed a significantly lower number of postoperative sore throat (p-value at 1 h 0.032, at 6 h 0.024, and 24 h 0.044).
Table 2.
Incidence of postoperative sore throat
| n = number (%) | K VS C | ||
|---|---|---|---|
| Incidence of POST | Group-K | Group-C | p-value |
| 1 h post-extubation | 7 (23.3) | 15 (50) | 0.032 |
| 6 h post-extubation | 5 (16.7) | 13 (43.3) | 0.024 |
| 24 h post-extubation | 4 (13.3) | 11 (36.7) | 0.044 |
In Table 3, the ketamine group showed a smaller number of the severe sore throat throughout the observation period but they were not significantly lower than the control group.
Table 3.
Severity grading of postoperative sore throat
| Incidence of different grades of POST | 1 h post extubation | 6 h post extubation | 24 h post extubation | |
|---|---|---|---|---|
| N = 30 | N = 30 | N = 30 | ||
| Group-K | No POST (0) | 22 | 23 | 26 |
| Mild (1) | 2 | 2 | 3 | |
| Moderate (2) | 3 | 3 | 1 | |
| Severe (3) | 3 | 2 | 0 | |
| Group- C | No POST (0) | 15 | 17 | 19 |
| Mild (1) | 5 | 2 | 3 | |
| Moderate (2) | 4 | 4 | 3 | |
| Severe (3) | 6 | 6 | 5 | |
| p-value | K vs C | 0.164 | 0.090 | 0.055 |
In the control group 23.3, 13.3 and 10 percent of patients reported cough at 1 h, 6 h, and 24 h respectively. In the ketamine group, patients reported cough 6.7, 5.7 percent at 1 h and 6 h and there was no patient having cough at 24 h as seen in Table 4. But ketamine failed to prove significantly effective in controlling cough (p-value at 1 h 0.071, at 6 h 0.389, and 24 h 0.238).
Table 4.
Incidence of postoperative cough
| N = number (%) | K vs C | ||
|---|---|---|---|
| Incidence of cough | Group-K | Group-C | p value |
| 1 h post-extubation |
2 (6.7) |
7 (23.3) |
0.071 |
| 6 h post-extubation |
2 (5.7) |
4 (13.3) |
0.389 |
| 24 h post-extubation | 0 |
3 (10) |
0.238 |
In the ketamine group, 23.3, 10 and 3.3 percent of patients reported hoarseness of voice at 1 h, 6 h, and 24 h respectively whereas in the control group 33.3,20 and 6.7 percent patients complained about hoarseness of voice as seen in Table 5. Ketamine gargle had an insignificant effect reducing postoperative hoarseness of voice (p-vale at 1 h 0.390, at 6 h 0.278, and 24 h 0.554).
Table 5.
Incidence of postoperative hoarseness of voice
| N = number (%) | K VS C | ||
|---|---|---|---|
| Incidence of HOV | Group-K | Group-C | p-value |
| 1 h post-extubation |
7 (23.3) |
10 (33.3) |
0.390 |
| 6 h post-extubation |
3 (10) |
6 (20) |
0.278 |
| 24 h post-extubation |
1 (3.3) |
2 (6.7) |
0.554 |
Patients were followed for 24 h after extubation. Patients with severe sore throat after 24 h were given lukewarm saline gargle and decongestants and the ones who did not respond to the above were sent for otorhinolaryngology consultation.
Discussion
Postoperative sore throat has been reported as one of the most undesirable postoperative outcomes after tracheal intubation under general anesthesia. Ignoring it can lead to a longer hospital stay, increased morbidity, and unpleasant long-term memories [9]. General anaesthesia related cough may lead to haemodynamic responses like hypertension, arrhythmias, tachycardia, wound dehiscence, increased intraocular and intracranial pressure [10].
In our study, gender distribution had an insignificant impact on a postoperative sore throat, which was similar to the findings of studies by Ibrahim et al. [11], Amingad et al. [12] and Rajkumar et al. [13]. However, Higgins et al. [14] and Biro et al. [15] stated that female gender was more prone to POST. The possible explanation for their inference of higher incidence in female patients could be a smaller airway leading to more mucosal injury.
From our study, we concluded that other variables like age, BMI, Mallampati score, ASA score, number of intubation attempts had no significant effect on postoperative sore throat (p-value ≥ 0.05). Aigbedia et al. [16] proposed that prolonged duration of anesthesia might lead to the increased postoperative sore throat by more mucosal and nerve injury. However, we foundthe effect of duration of anesthesia insignificant on POST, which correlates with studies done by Kang et al. [17].
As the primary outcome of our study, the incidence of postoperative sore throat in the ketamine group was 23.3%, 16.7%, and 13.3% respectively at 1 h, 6 h, and 24 h after extubation. This result was similar to the study by Kajal et al. [1] which was 24, 24 and 12 percent at 1 h, 4 h, and 24 h respectively. Ahigher number of patients in the ketamine group reported postoperative sore throat in the study by Lalwani et al. [18] which was 38.8% at 2 h, 25% at 4 h, and 20% at 24 h. On the other hand, Ibrahim et al. [11] found a lower incidence rate in their study (13.3% at 2 h, 3.3% at 4 h and 0% at 24 h). This wide range of incidence reported might be due to the subjective nature of the diagnosis of postoperative sore throat and different pain tolerance levels in different people.
We found that ketamine gargle significantly decreased throughout the observation period in comparison with the control group (p-value 0.032, 0.024, 0.044) which was similar to the study by Kuriyama et al. [19], Lalwani et al. [18] and Rudra et al. [20] Trauma to the respiratory tract mucosa during airway instrumentation and due to prolonged pressure of tracheal tube during general anesthesia leads to aseptic inflammation of the respiratory tract mucosa. This inflammatory process might be reduced by ketamine gargle. Zhu et al. [21] proposed a protective effect of ketamine on allergic airway inflammation. That potential protective effect via NMDA receptor antagonism, ketamine gargle might help reduce postoperative sore throat in patients undergoing tracheal intubation.
In our study, the numbers of severe cases of postoperative sore throat were less than the control group however, ketamine failed to produce any significant impact in mitigating severity. This finding confirmed the similar findings in the study by Kajal et al. [1]
Similarly, ketamine gargle had no significant role in attenuating postoperative cough and hoarseness of voice throughout the observation time.
Based on the potential protective effect via NMDA receptor antagonism, ketamine gargle might help reduce postoperative sore throat in patients undergoing tracheal intubation which is similar to the findings of Kajal et al. [1] in their study with intravenous dexamethasone, topical betamethasone, and ketamine gargle in reducing postoperative sore throat among patients undergoing general anesthesia and tracheal intubation.
Conclusion
Ketamine gargle prepared with 40 mg injection ketamine and 29 ml normal saline showed significant efficacy in attenuating postoperative sore throat in patients posted for elective surgeries under general anesthesia with tracheal intubation. Moreover, ketamine gargle is very affordable to patients from any economic background. This study could establish ketamine gargle as an effective measure in decreasing postoperative throat complaints resulting in less morbidity and shorter hospital stay.
Declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Human and Animal Rights
No animals or human subjects were injured in our study.
Informed Consent
A written informed consent was taken from the patients in the study.
Footnotes
Publisher's Note
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Contributor Information
Anisha Puri, Email: anishabehal@gmail.com.
Subir Kumar Ghosh, Email: skgnrsmc@gmail.com.
Gurchand Singh, Email: drgurchand@gmail.com.
Anita Madan, Email: dranitapuri@gmail.com.
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