Effect of intratracheal dexmedetomidine combined with ropivacaine on postoperative sore throat:A prospective randomised controlled study

Introduction Endotracheal intubation involves inserting a tube into the trachea to facilitate mechanical ventilation during general anaesthesia While essential this procedure can injure the airway mucosaleading to postoperative sore throat POSTa common complication with an incidence rate of up to 61 point 8 percentage 1 POST can cause significant discomfort negatively affecting patient satisfaction

To mitigate POSTvarious prophylactic methods have been explored including

Nebulised agents such as ketamine dexmedetomidine steroids and magnesium sulphate

Intravenous administration of lidocaine and dexamethasone

Topical spray with local anaesthetics2

Choosing appropriate size of the endotracheal tube

Optimal endotracheal tube cuff pressure

Replacing a double lumen tube with an endobronchial blocker

Each of these interventions has its own limitations and varying degrees of effectiveness

Ropivacainean amide local anestheticblocks voltagegated sodium channels in nerve cells inhibiting nerve impulse conductionSeveral studies have explored the use of topical local anesthetic sprays and jellies to reduce sore throat hoarsenessand tracheal irritation associated with endotracheal intubation3 Topical ropivacaine has been utilized to mitigate the hemodynamic response during intubation and extubation while also reducing the incidence of peri extubation cough

Dexmedetomidine an alpha2 adrenergic receptor agonist exerts sedative anxiolytic and analgesic effects 4 It has been used as an additive to local anesthetics to prolong analgesia and has also been administered intravenously and via preoperative nebulization to reduce the incidence of POST However limited research has investigated its intratracheal administration as a potential method to modulate the hemodynamic response to endotracheal intubation and prevent POST

Therefore we hypothesized that intratracheal administration of dexmedetomidine combined with ropivacaine could effectively reduce both the incidence and severity of POST following endotracheal intubation

Need for the study POST is a minor but distressing complication for a patient after GA Various prophylactic pharmacological and nonpharmacological measures have been studied to reduce the incidence and the severity of the same We hypothesize that the intratracheal route of administration of drugs may have lesser side effects compared to intravenous route and may be more effective as it is in direct contact with the tracheal mucosal surface As very few studies have been conducted to evaluate the use of intratracheal drugs on POST we plan to conduct this study to determine the use of Dexmedetomidine combined with Ropivacaine for prevention of POST

Objectives of the study

Primary Objective

To evaluate the effect of intratracheal instillation of Dexmedetomidine with Ropivacaine compared with normal saline on the incidence and grading of postoperative sore throat

Secondary Objectives

1To study the incidence and grading of postoperative hoarseness of voice

1To assess haemodynamic response to endotracheal intubation by comparing the vitals heart ratesystolic diastolic and mean arterial blood pressure between the two groups at specific time points

2 To note adverse reactions if any

Materials and methods

Source Of Data St Johns National Academy Of Health SciencesBengaluruStudy Period 2 Years

Study Design Randomized Controlled TrialSample Size 30 patients Per Group

a SUBJECTS

Inclusion criteria

Patients of ASA Physical status I-II of either sex

Mallampati Grading of airway I and II

18 to 59 years of age scheduled for surgeries under General Anesthesia with oral endotracheal intubation and in supine position

Exclusion criteria

BMI more than or equal to30 kg per metre square

Maxillofacial and head and neck surgery and surgeries requiring packing the throat

Stylet guided intubation

More than one intubation attempt

Nasogastric tube insertion

Videolarygoscope aided intubation

Methodology

A prospective randomized double blind study will be conducted after obtaining approval from

the Institutional Ethics Committee IECand written informed consent

60 patients between the age of 18 59 years belonging to ASA Physical Status I or II undergoing surgeries in the supine position under general anaesthesia with an oral endotracheal tube will be recruited for the study

Using a computergenerated sequence patients will be randomly allocated into two groups Details of the group assignments will be sealed in sequentially numbered opaque envelopesv One anaesthesiologist will prepare the study drug in a syringe according to group assignment Another anaesthesiologist who will be blinded to the group assignments will inject the study drug intubate the patient and record the study parameters

Group DR Patients will receive intratracheal 075 percentage ropivacaine 4 mland dexmedetomidine 50 mcg made upto 5 ml with normal saline

Group S Patients will receive intratracheal normal saline 5 ml

All patients will be subjected to a detailed pre-anesthetic evaluation

On the day of surgery nil per oral status will be confirmed Standard American Society of Anesthesiologists ASA monitors will be attached to the patient and baseline vitals such as heart rate HR Systolic blood pressure SBP Diastolic blood pressure DBP Mean Arterial Pressure MAP and oxygen saturation SPO2 will be recorded

Intravenous access will be secured and a balanced salt solution will be started.

Patients will be first preoxygenated with 100 percent oxygen for 3 minutes. Premedication consisting of 10 mcg per kg glycopyrrolate 01mg per kg ondansetron and 001 mg per kg midazolam intravenously iv will be given Induction will be done using fentanyl 2 mcg per kg and propofol 1 2 mg per kg iv till loss of verbal response Injection atracurium 0 5mg per kg iv will be given for muscle relaxation

After 3 minutes of injecting the relaxant direct laryngoscopy using Macintosh laryngoscope will be done and 5 ml of the study drug will be sprayed onto the glottis and into the trachea using a mucosal atomizer device for uniform surface anesthesia The patient will be ventilated for 2 minutes and then intubated with a cuffed polyvinyl chloride PVC endotracheal tube of size 7 mm in females and 8 mm in males using a MacIntosh laryngoscope All intubations will be done by an experienced Anaesthesiologist

Air entry will be checked bilaterally and tube position confirmed by end tidal CO2 ETCO2 tracing The endotracheal cuff will be inflated and maintained at a pressure of 2030 cm H2O with the help of a cuff pressure manometer Anesthesia will be maintained with oxygen air and Isoflurane and intermittent bolus doses of Atracurium Intraoperatively patients will receive routine standard of care

At the end of surgery the neuromuscular block will be reversed with injection glycopyrrolate 10 mcg per kg and injection neostigmine 005 0 07 mg per kg iv After adequate recovery patients will be extubated

The SBP DBP MAP SPO2 before induction T0 before surface anesthesia T1 after surface anesthesia T2 before intubation T3 after intubation T4 and 1 min after intubation T5 3mins after intubation T6 and 5 mins after intubation T7 will be noted

Severity of sore throat and hoarseness of voice will be assessed at 0 2 6 12 and 24 hr after extubation as per the grading criteria below

Grading of Sore Throat

0No sore throat

1 Mild sore throat complained of sore throat only when asked

2Moderate sore throat selfreported sore throat

3Severe sore throat pain and discomfort in the pharynx causing hoarseness or vocal change

Grading of Hoarseness of voice

0 No hoarseness

1 Mild hoarseness complained of hoarseness only when asked

2 Moderate hoarseness selfreported hoarseness

3Severe hoarseness observable change in voice