Comparison of the effects of supraglottic airway device and endotracheal tube on intracranial pressure in patients undergoing elective surgeries

The evolution of airway management highlights a shift towards supraglottic airway devices (SGAs) due to their advantages in minimizing post-operative complications and improving patient outcomes. Several studies have compared SGAs like LMA Protector to endotracheal tubes (ETT) in various surgical procedures, demonstrating benefits such as reduced hemodynamic stress response, lower incidence of post-operative symptoms, and better ventilatory parameters. Meta-analyses have also shown that second-generation SGAs provide better oropharyngeal leak pressure, with the LMA Protector exhibiting the highest efficacy. However, these devices have been sparingly studied in terms of ICP response. Rise in ICP noticed during tracheal stimulation during intubation would be well tolerated by healthy patients, but may be detrimental for certain subset of patients.Thus the current study aims to compare the effectiveness of the Laryngeal Mask Airway Protector (a second-generation supraglottic airway device) with the traditional endotracheal tube (ETT) in multiple aspects, primarily by assessing their impact on intracranial pressure as measured through Optic nerve sheath diamter (ONSD).The other comparative aspects include hemodynamic response, clinical performance of the devices and post-operative complications associated with their usage. The hypothesis is that SGAs will result in reduced alterations in ONSD, indicating potentially safer airway management.

Aim

To compare the effect of supraglottic airway device (LMA Protector) and endotracheal tube on intra cranial pressure as measured through optic nerve sheath diameter (ONSD) using transocular ultrasonography in patients scheduled to undergo elective surgeries.

Objectives

1. To compare the first attempt success rate between supraglottic airway device (LMA Protector) and endotracheal tube.

2. To compare the insertion time between supraglottic airway device (LMA Protector) and endotracheal tube.

3. To compare the ONSD measurements at various time intervals during surgery between supraglottic airway device (LMA Protector) and endotracheal tube.

4. To compare the hemodynamic response as measured through SBP, DBP, MAP and HR at various time intervals during surgery for both supraglottic airway device (LMA Protector) and endotracheal tube.

5. To compare the post-operative outcomes with respect to occurrence and severity of complications like sore throat, dysphagia and dysphonia for both supraglottic airway device (LMA Protector) and endotracheal tube.

Methodology

Participants will be randomly assigned to either the supraglottic airway (SGA) group or the ETT group.The study protocol outlines thorough pre anaesthesia workup including physical examinations, various tests and assessment of difficult airway. Patients will be advised on fasting and will be pre-medicated according to institutional guidelines. During anesthesia induction, standard procedures will be followed, including pre-oxygenation, induction with propofol and neuromuscular blockade. Airway management will vary based on group allocation, either with a supraglottic airway device (LMA Protector) or endotracheal intubation (ETT), with specific techniques outlined for each. Monitoring parameters, including hemodynamic parameters and optic nerve sheath diameter (ONSD), will be closely observed at designated time points pre and post-insertion of the airway devices. Analgesics and anti-emetics will be administered as necessary, and reversal agents will be used post-surgery. The study will also evaluate the post-operative complications like sore throat, dysphagia and dysphonia.

Outcome Measures

Following observations will be recorded in all the patients:

1. Number of attempts taken to establish an effective airway

2. Time for achieving effective airway- defined as the time from picking up of the airway device to the correct placement of it, which would be seen with one effective end tidal capnography waveform.

3. Optic nerve sheath diameter in millimeter will be measured before induction/baseline (T0), 1 minute after SGA placement/ ETT intubation (T1), 5 minutes after SGA placement/ ETT intubation (T5) and 10 minutes after SGA placement/ ETT intubation (T10).

4. Intraoperative hemodynamic parameters [SBP, DBP, MAP and HR] will be recorded pre induction (T0), 1 min after SGA placement/ ETT intubation (T1), 5 minutes after SGA placement/ ETT intubation (T5) and 10 minutes after SGA placement/ ETT intubation (T10).

5. Any adverse outcomes during the procedure like oxygen desaturation, soft tissue or dental trauma, blood stains on device.

6. The incidence and sore throat, dysphagia and dysphonia will be checked at 1 hour, 6 hours and 24 hours after surgery.

7. Degree of postoperative sore throat using a numerical rating scale, if any.