Title:

Comparative Analysis of Post-Operative Sore Throat; Incidence and Severity in Patients Undergoing Prone Position Spine Surgery utilizing Non-Neuromuscular Blockade with Total Intravenous Anaesthesia Versus Neuromuscular Blockade Approaches.

Introduction:

Post-operative sore throat (POST) is a common complaint following tracheal extubation after surgery. It is characterized by pain, irritation, or discomfort in the throat, often exacerbated by swallowing or speaking (1). While typically a transient and benign condition, POST can cause significant discomfort for patients, leading to dissatisfaction and potentially prolonging recovery. The mechanism is believed to involve erosion of the tracheal mucosa caused by the cuff of a tracheal tube, trauma from tracheal intubation and mucosal dehydration. Understanding the incidence, risk factors, and treatment options for POST is crucial for effective post-operative management (1).

The reported incidence of POST varies widely across studies, ranging from 21% to 65% (1,2). Several factors contribute to this variability, including patient demographics, type and duration of surgery, anaesthesia techniques, and post-operative care protocols (3). Generally, longer duration surgeries, female gender, younger age, and certain comorbidities are associated with higher rates of POST.

Risk factors encompass prolonged intubation, specific surgical procedures, anaesthesia methods. Treatment options include pharmacological approaches such as NSAIDs, topical anaesthetics, and corticosteroids, as well as non-pharmacological measures like humidification, throat lozenges, and hydration (4,5). Preventive strategies involve optimizing intubation techniques, utilizing specialized endotracheal tubes, employing multimodal analgesic approaches, and educating patients about POST expectations and self-care measures.

Total intravenous anaesthesia (TIVA) is a technique used to administer anaesthesia during surgery entirely through intravenous medications, without the use of inhaled anaesthetics (6). While TIVA offers several advantages, such as precise control of anaesthetic depth and reduced risk of post-operative nausea and vomiting, it can also be associated with post-operative sore throat (POST) following tracheal intubation. The incidence of POST in patients underwent surgery in supine position under TIVA was estimated to be around 50 % as mentioned in previous literature (7)

Prone positioning achieved during most of the spine surgeries involves placing the patient face down on the operating table. Patients positioned prone demands meticulous attention to ensure proper alignment with the airway, as improper positioning or excessive movement during surgery can cause mucosal irritation and post-operative sore throat (POST). Prone positioning subjects the patient’s neck and throat to pressure, potentially compressing the airway and heightening the risk of mucosal trauma, which may be exacerbated by surgical devices and padding supporting the body. Additionally, managing the airway in prone patients presents challenges compared to supine positioning, potentially leading to increased tube manipulation and difficulty in interventions, further contributing to POST (8). Prolonged procedures in the prone position can exacerbate these risks, as prolonged pressure on the airway and exposure to anaesthetic gases increase the likelihood of endotracheal tube irritation and POST.

This study is being planned to compare the incidence of POST in patients undergoing spine surgery in prone position with neuromuscular blocking agents or without neuromuscular blockers under TIVA with intraoperative neuro-physiological monitoring as there is little information available in the literature about the incidence of POST in patients with prone spine surgeries under Total Intravenous Anaesthesia (TIVA)

Research Question:

Dose the incidence and severity of postoperative sore throat (POST) in patients undergoing spine surgery in prone position utilizing Non-Neuromuscular Blockade with Total Intravenous Anaesthesia is different compared to Neuromuscular Blockade Approaches.

Aims and Objectives:

Primary Objective:

To evaluate the incidence of POST in patients undergoing spine surgery in prone position utilizing Non-Neuromuscular Blockade with Total Intravenous Anaesthesia compared to Neuromuscular Blockade Approaches.

Secondary Objectives:

1.     To determine the severity of POST (mild/moderate/severe).

2.     To know any complications related with upper respiratory tract eg hoarseness/ roughness/ / URTI/ dysphagia.

3.     Total doses of oral Lozenges required in case of moderate to severe post operative sore throat

Methodology:

Study design: A Prospective Non-randomized double blinded parallel group observational study.

Study site: Operation theatre (Neurosurgery), Department of Anaesthesiology, SGPGIMS, Lucknow.

Study duration: 24 months

Inclusion Criteria:

Age group 18-60 years, either sex

ASA I/II/III with MPG 1&2

BMI<35kg/m2

Scheduled for elective thoracic/lumbar/lumbosacral surgical procedures under prone position

Exclusion Criteria:

1.     Anticipated difficult airway

2.     Patients with Ryle’s tube in-situ.

3.     History of upper respiratory tract infection/asthma/COPD

4.     Psychiatric history

5.     Use of steroids or anti-inflammatory agents in last week

6.     Previous surgery within 2 weeks

7.     History of trauma to oral cavity/nose/throat/head

Intervention:

This study will be initiated after approval from the institutional ethical committee (IEC) and written informed consent from patients undergoing spine surgery. After a thorough pre-operative evaluation, patients will be premeditated with oral alprazolam 0.5 mg the night before surgery with sips of water. Oral ranitidine tablet 150mg will be give to all patients a night before and in morning of surgery in all patients.

In the operation theatre, standard ASA monitoring in the form of electrocardiogram (ECG), pulse oximeter (SpO2), and non-invasive blood pressure (NIBP), Temperature, ETCO2 will be done. An intravenous access will be secured and Anaesthesia will be induced with fentanyl 2 μg/kg and propofol 2 mg/kg. Tracheal intubation will be facilitated with vecuronium bromide 0.1 mg/kg followed by direct laryngoscopy using a Macintosh laryngoscope blade by applying minimal pressure and insertion of an sterile flexo-metallic endotracheal tube (7.5 mm inner diameter for females and 8.5 mm inner diameter for males).

Laryngoscopy and endotracheal intubation will be performed by anaesthesia faculty with a minimum experience of 6 years. Endotracheal tube will be lubricated with sterile water-soluble jelly (Lubic (K); Neon Laboratories, Mumbai, India). The cuff will be inflated with air maintaining cuff pressure of 18-22 cm of water. Cuff pressure will be measured with the help of a pressure-monitoring transducer (Edward Life Sciences, LIC Irvine, CA) by connecting it to a pilot balloon of the endotracheal tube. Patient’s lungs will be ventilated with O2 in air (fraction of inspired oxygen [Fio2] −0.4), keeping the end-tidal CO2 between 32 -35 mm Hg.

After successful Endotracheal intubation, prone positioning will be achieved considering all precautions.

Anaesthesia will be maintained with infusion ketofol (1:4) or injection vecuronium with intermittent fentanyl doses depending on group allocation. A heat and moist exchanger (HME) filter will be used through-out the surgery to provide humidification of the anaesthetic gases.

Sample size calculation:

The primary aim of the study is to estimate the incidence of the sore throat among the patient’s undergoing spine surgery among two groups TIVA and Muscle relaxant. Based on the inputs taken from the previous studies, incidence of the sore throat in the TIVA (Maruyama et al 2004), and control group (Aqil M et al, 2017) to be 50% and 20% respectively. At minimum two-sided 95% confidence interval and 80% power of the study required 39 patients in each of the two groups. Finally, we will target to include 50 patients in each of the two groups. Sample size was estimated using the software G*Power version 3.1.9.2. 

Patients will be divided into two groups containing 50 patients in each group:

Group M: Patients will receive injection vecuronium with infusion dose of 0.1 mg/kg/hr with intermittent doses of injection Fentanyl 50 Mcg every hourly through-out the surgery. At the end of surgery all patients will receive injection Neostigmine 0.05 mg/kg and glycopyrolate 0.01 mg/kg for adequate reversal of neuromuscular junction receptor blockage.

Group T: Patients will receive total intra-venous anesthesia (TIVA) with Ketofol. ketofol solution (total 50 mL) will be prepared by adding 2 mL of ketamine (100 mg; 50 mg/mL), 40 mL of 1% propofol (400 mg; 10 mg/mL), and 8 mL of saline. Thus, the effective concentration of ketamine (2 mg/mL) and propofol (8 mg/mL) will be 1:4 (mg) in the prepared solution. TIVA will be started after initial bolus dose of muscle relaxant and TOF count of >75 %. Intraoperative Neurophysiological monitoring will be performed under TIVA during the surgery.

Depth of anesthesia will be maintained using Bi-Spectral Index keeping BIS values between 40-60 in both the groups. Intraoperative body temperature will be maintained between 36°C and 37°C in all patients. At the end of surgery, supine position will be achieved and infusion will be stopped and tracheal extubation will be performed by the same faculty in all patients after gentle suctioning of oral secretions by a 12 F suction catheter. In the post-operative period, all patients will be given standard multimodal analgesia regime with inj. Paracetamol 1gm 6hrly with injection tramadol 50 mg  SOS as per the institutional protocol.

Post operative sore throat will be assessed by another anesthesia faculty who has experience of 6-8 year in each patient before leaving the operation theater after adequate verbal and motor response and at 2 hr, 6hr, 12 hr and 24 hr after extubation. During first evaluation, sedation will be assessed with a modified Ramsay sedation score (RSS): 1, patient anxious or agitated or both; 2, patient cooperative, oriented and tranquil; 3, patient responds to commands only; 4, patient responds to a light glabellar tap; 5, patient does not respond (7).

Patients with a modified RSS of 1, 4 or 5 Will be regarded as inappropriate candidates for this study and will be excluded.

POST will be graded on a 4-point scale (0-3), 0= no sore throat,1= mild sore throat (complains of sore throat only on asking), 2= moderate sore throat (complains of sore throat on his/her own); and 3 = severe sore throat (change of voice or hoarseness, associated with throat pain).

Statistical Analysis:

Continuous variables will be presented in mean ± SD / median (interquartile range) along with range depend upon the normality of the data. To compare the means / medians between two groups, independent samples t test / Mann Whitney U test to be used. Two repeated Measures ANOVA or its non-parametric methods to be used to test the association between the study groups and change in the Hemodynamic parameters over the time. Categorical variables will be presented in number (%) and compared by the Chi-square test / Fisher exact test as applicable. Statistical analyses will be performed using Statistical package for social sciences version-23 (SPSS-23, IBM, Chicago, USA).  P value <0.05 to be considered as statistically significant.

Data collection:

1. Baseline demographic data including age, gender, BMI, medical history, and smoking status, to assess potential confounding variables.

2. Intraoperative variables including surgical duration, type of surgery, intraoperative complications, and anesthetic agents used.

3. Assessment of severity of POST using 4-point scale