Supraglottic Airway Device

Supreglottic Airway Device.

1. SUPRA GLOTTIC AIRWAY DEVICE Dr. Debojyoti Dutta Moderator- dr.sushil bhati S.M.S. MEDICAL COLLEGE

2. INTRODUCTION Devices that are used to maintain the airway patency and provide ventilation by placing just above the glottic opening. They sit outside the trachea and provide a hands free means of gas tight airway. Standard of airway management , filling the niche between facemask and tracheal tubes. Dr. Archie Brain developed LMA in 1982 as a modification of Goldman dental mask with ET tube. The first commercially available supraglottic airway device was LMA-Classic(1988).

3. CLASSIFICATION Based on Generation :- LMA First Generation Simple airway device. Low pressure pharyngeal seal May or may not protect from aspiration. Have no specific design to lessen the risk. Eg .- cLMA Flexible LMA All LMs Laryngeal tube Cobra perilaryngeal airway Second Generation Specially designed for safety. High pressure pharyngeal seal. Reduce the risk of aspiration. May be more efficacious in ventilation. Eg .- PLMA, Supreme LMA, Laryngeal tube suction 2, Laryngeal tube suction D, i -gel, SLIPA.

4. CLASSIFICATION Based on sealing mechanism – 1.Cuffed perilaryngeal sealer:- Non-directional non esophageal Sealers- cLMA , Flexible LMA, LMA unique. Directional Non-esophageal sealing- Fastrach LMA, ALMA. Directional esophageal sealing- Proseal LMA, Suprem LMA. 2.Cuffed pharyngeal sealer:- Without esophageal sealing: COPA, PAX. With esophageal sealing: Combitube , LT, LTS. 3.Cuff less preshaped sealer: - With esophageal sealing- Baska mask, i -gel. Without esophageal sealing- SLIPA , AirQ -SP.

5. CLASSIFICATION BASED ON THE NUMBER OF LUMEN- 1.Single Lumen Devices:- LMA-classic, LMA-unique, LMA-flexible, ILMA, C- trach , Soft seal, Laryngeal Airway Device(LAD), Ambu Laryngeal Mask, Pharyngeal airway express(PAX), Cobra Perilaryngeal Airway(CPLA), Laryngeal Tube(LT), Cuffed oropharyngeal airway, Stream Lined Liner of the Pharyngeal Airway(SLIPA), Glottic Aperture Seal Device. 2.Double Lumen Devices:- Proseal LMA, Combitube , Laryngeal Tube Suction(LTS), Airway Management Device(AMD). 3.Tripple Lumen Devices:- Elisha Airway Device(EAD).

6. INDICATION Alternative airway during GA specially in short surgical procedures and minor therapeutic or diagnostic procedures like radiation therapy, diagnostic and interventional radiology, endoscopy, ECT etc. Cardiopulmonary resuscitation to secure the airway. Essential part of difficult airway trolley. Primary airway device when urgent airway patency is required in lateral position as lesser time required to place LMA in the lateral position as against endotracheal intubation in this position. Relative indication- in professional singers to avoid vocal cord trauma.

7. CONTRAINDICATION Limited mouth opening (< 2 fingers) Local pathology in pharynx , larynx or upper airway. Trismus , facial or upper airway trauma Increase risk of aspiration- Morbid obese, > 14 week pregnant, prior opiods medication, delayed gastric empting, acute abdominal or thoracic injury, history of GERD, and hiatus hernia. Reduced lung compliance/increase work of breathing

8. ADVANTAGES Increased speed and ease of placement. Less requirement of expertise. Improved hemodynamic stability at induction and during emergence of anesthesia. Minimal IOP and ICP changes during insertion. Increase airway tolerance. Lower frequency of coughing during emergence. Improved oxygen saturation during emergence DISADVANTAGE Inadequate positive pressure ventilation. More chances of aspiration of gastric content. Sore throat. Vascular compression and nerve damage.

9. LMA- Classic Comprised of three main components Airway Tube Mask Inflation line Mask designed to conform to the contours of the hypopharynx with its lumen facing the laryngeal opening. Made of medical grade silicone, it can be autoclaved and reused many times. Seal pressure =25cmH2O

10. SIZE SELECTION Mask Size Patient size /Body Weight Maximum Cuff Inflation Volume (Air) 1 Neonates/Infants up to 5 kg Up to 4 mL 1.5 Infants 5–10 kg Up to 7 mL 2 Infants/Children 10–20 kg Up to 10 mL 2.5 Children 20–30 kg Up to 14 mL 3 Children 30–50 kg Up to 20 mL 4 Adults 50–70 kg Up to 30 mL 5 Adults 70–100 kg Up to 40 mL 6 Large Adults over 100 kg Up to 50 mL

11. PREPARATION PRIOR TO INSERTION Select the proper size of LMA. Inspect the LMA for any tear , blockage . Slowly deflate the cuff to form a smooth flat wedge shape . Over inflate: look for leak. Use a water soluble lubricant to lubricate the posterior surface of LMA just prior to insertion. Avoid excessive amounts of lubricant -on the anterior surface of the cuff or -in the bowl of the mask. Avoid lignocaine jelly for lubrication .

12. INSERTION TECHNIQUE Position: Neck flexed and head extended. Use non-inserting hand to stabilize occiput . Jaw should be pulled down by assistant. LMA tube be grasped like a pen with index finger pressing the point where tube joins mask. Place the tip of the LMA against the inner surface of the patient’s upper teeth. Aperture facing forward, the tip pressed upwards against the hard palate. Mask is advanced into pharynx to ensure that tip remains flattened and avoids the tongue.

13. Continue.. Neck is kept flexed and head extended. Press the mask into the posterior pharyngeal wall using the index finger. Continue pushing with your index finger and g uide the mask downward into position. Grasp the tube firmly with the other hand and then withdraw your index finger from the pharynx. Press gently downward with your other hand to ensure the mask is fully inserted.

14. Continue.. Inflate the mask with the recommended volume of air. Do not over-inflate the LMA. Normally the mask should be allowed to rise up slightly out of the hypo pharynx as it is inflated to find its correct position. Insert a bite-block or roll of gauze to prevent occlusion of the tube. Now the LMA can be secured utilizing the same techniques as those employed in the securing of an endotracheal tube.

15. OTHER METHODS OF INSERTION 1. Thumb index method. 2.Partial inflation method. 3.180 degree rotation method. 4.Laryngoscopy aided method. 5.Stylet aided method. 6.Insertion from the side of the mouth opening.

16. SIGNS OF CORRECT PLACEMENT The slight outward movement of the tube upon LMA inflation. The presence of a smooth oval swelling in the neck around the thyroid and cricoid area, or no cuff visible in oral cavity. Ventilate the patient while confirming equal breath sounds over both lungs in all fields and the absence of ventilatory sounds over the epigastrium . Part of LMA Position Distal tip of silicone cuff Upper esophageal sphinter Sides of the cuff Pyriform fossa Upper part of the cuff Tounge base

17. PROBLEMS Failure to press the deflated mask up against the hard palate or inadequate lubrication or deflation can cause the mask tip to fold back on itself. Once the mask tip has started to fold over, this may progress, pushing the epiglottis into its down-folded position causing mechanical obstruction . If the mask tip is deflated forward it can push down the epiglottis causing obstruction If the mask is inadequately deflated it may either push down the epiglottis enter the glottis.

18. INTUBATION WITH C-LMA 1.Blind intubation. 2.Fibrescope guided. 3.retrograde. 4.Lighted stylet guided. 5.Nasotracheal intubation. DISADVANTAGES :- 1.Standard tube not long enough to insert. 2.Pilot tube may kincked . 3.Cricoid pressure make it difficult to pass the tube. 4.Paediatric-largest uncuffed tube too small to allow good seal for PPV. 5.Removal of the LMA disturbs the ET tube 6. PPV not always possible due to moderate pharyngeal seal. 7.More risk of aspiration

19. Steps to reduce the chance of aspiration Avoid in patients who are un-fasted, or have factors predispose to regurgitation. Routinely test the cuff for defects before use. Avoid lubricating the anterior surface of the mask, since the lubricant may be aspirated. Insert the LMA only when adequate depth of anesthesia has been reached. Avoid disturbing the patient during emergence from anesthesia. Keep the cuff inflated till the patient is awake. Action after aspiration Do not attempt to remove LMA. Disconnect the circuit and allow to drain the fluid while head is down & to the side. Suction the LMA & give 100% O2. Ventilate manually with low gas flow & small TV. Evaluate tracheobronchial tree & suction the remaining fluid with FOB. Intubate when aspiration below vocal cords.

20. LMA - UNIQUE Single use , PVC made , cheaper. Tube – stiffer , Cuff- less compliant. Less rise of intracuff presuure with N2O. More difficult to insert. Size same as cLMA .

21. FLEXIBLE LMA Flexometallic tube- narrower & longer. Has a rigid preformed angle at the cuff. Seal pressure=20cmH2O More difficult to insert. Introducer helps to stabilize the airway tube during insertion & it is removed once mask is in place. It has a less incidence of dislodgement once placed. More useful in head & neck surgeries, ENT and upper torso procedures where need to reposition the airway is prevalent Problems- Disruption of spiral reinforce wire, Increased airway resistance , limits endoscope & tracheal tube passage , unsuitable for MRI.

22. AMBU AURA LARYNGEAL MASK Ambu Auraonce - single-use LM with a preformed curve. The Ambu Aura40 is the reusable, silicone version of the Ambu AuraOnce . The Ambu Aura- i designed to facilitate intubation like ILMA. Three parts- an airway tube, a mount area, and a bowl including the inflatable cuff .. All these three areas are molded as single unit for extra safety - no separation .. Facilitate insertion without exerting force on the upper jaw in neutral position. A reinforced tip reduces the risk of the device folding back during insertion. integrated inflation line and no epiglottic bars at the airway orifice.

23. SOFT SEAL LARYNGEAL MASK similar to the single-use LMA. The ventilation orifice is wider and it is characterized by the absence of mask aperture bars. Cuff is more elliptical. insertion with the cuff partially inflated is recommended. A maximum intracuff pressure of 60 cm H2O is recommended. may be used as an intubation conduit. The large bowl of the device and its PVC Construction inhibit easy insertion.

24. PERILARYNGEAL AIRWAY single use, PVC made, latex free . It has a breathing tube with a large inner diameter to increase air flow. In the proximal end it has a standard 15 mm connection Novel head design- Grill of soft bar with Cobra head shape. Lies infront of laryngeal inlet. Tip deflects epiglottis. Bars allow ventilation & instrumentation. Internal ramp to guide ETT to wards glottis Proximal high volume low pressure cuff- seals hypopharynx . PLA offers a more effective seal, and a better fiberoptic score as the c-LMA.

25. ADVANTAGES Easy to insert. Large lumen allows larger ETT & fibrescope . Sealing pressure higher than C-LMA. Can be used for parcutaneous dilatational cricothyroidotomy . DISADVANTAGES Less airway protection –as tip lies above the oesophageal inlet. Airway obstruction.

26. INTUBATING LARYNGEAL AIRWAY medical-grade silicon and latex free. airway tube is curved similar to the anatomical curve of the upper airway to eliminate the need to bend the tube further during use, which can lead to kinking. Mask- keyhole outlet to direct ETT to laryngeal inlet. 3 ridges – on inflation of mask, these ridges move against the posterior pharynx and improve anterior mask seal. After intubation , ILA can be removed without dislodging the ETT using a reusable "ILA Removal Stylet ”. Low airway seal, high risk of aspiration.

27. INTUBATING LMA A modification of the c-LMA. A rigid (stainless steel) anatomically curved,short & wide bored shaft that follows the anatomical curve of the palate and the post pharyngeal wall. An epiglottic elevator bar at the mask aperture Armoured flexible ET tube with a longitudinal and a horizontal black line- coincides with the epiglottic elevating bar. The Stabilizer Rod of 25cm . Seal pressure=60cmof H2O max. Body weight ILMA size Air volume Tracheal Tube 30-50kg 3 20ml 7mm 50-70kg 4 30ml 7.5mm 70-100kg 5 40ml 8mm

28. INSERTION Position: Neutral Hold rigid handle parallel to patient’s chest. Glide the mask along the palate till the straight part of the rigid tube is parallel to the chin. Rotate the rigid handle directing towards patient’s nose till it can not be advanced. Inflate the cuff & check ventilation. Introduce FETT with black line faceing rigid handle till 15 cm mark. Now grip ILMA handle firmly and lift it forward by few mms without levering. Advance the tube using clinical judgment. Inflate the cuff and check for tracheal intubation.

29. Continue.. After confirmation of tracheal intubation deflate the ILMA cuff. Remove FETT connector Insert the stabilizing rod in the FETT to keep it in place. Remove the ILMA gently over the stabilizing rod until it is clear of the oral cavity. Stablize the FETT to prevent accidental extubation . Remove ILMA and the stabilizing rod. Reconnect FETT connector and the breathing circuit and confirm position again

30. CHANDY’S MANEUVER They increases the seal pressure and aligns the axes of trachea and FETT. First step : Rotating ILMA in coronal & sagittal plane in an attempt to find least resistant ventilation position. Second step : is to grasp the handle and use it to draw LMA forward 2-5 mm in a lifting action without levering teeth.

31. ADVANTAGES Useful in “can’t intubate , can’t ventilate” scenarios. Allows fast insertion into correct position without moving patient’s head or neck. Can be used alone or as a guide to intubation. Facilitates ventilation between ILMA insertion and ETT insertion Good conduit for fibreoptic intubation in presence of blood or clot in oral cavity. Difficult laryngoscopic view is irrelevent to the success of ILMA intubation. DISADVANTAGES More likely to dislodge in head or neck manipulation. Unsuitable for MRI. Difficulty in insertion with limited mouth opening. On removal of ILMA , tracheal tube can be displaced downwards.

32. PROSEAL LMA Reusable , silicon made , most specialized modification of c-LMA. Modifications:- ( i ) oesophageal drain tube (ii) posterior inflatable cuff (iii) reinforced airway tube (iv) integral bite block (v) introducer Higher leak pressure(35cm of H2O) than c-LMA(25cm of H2O). Size- in 7 sizes (1-5) like the C-LMA with drainage tube of 8,10,10,14,16,16&18 Fr respectively.

33. INSERTION ( i ) Standard: identical to the cLMA , but demanding careful attention to detail. (ii) Introducer: a metal introducer is attached to the concave side of the device. It is then introduced in the same manner as an intubating LMA. (iii) Bougie -guided: a bougie is placed upside down into the oesophagus and the PLMA is railroaded into place via the drain tube (suction catheters or orogastric tubes are alternatives).This technique had a significantly higher success rate. Positioning:- The easy passage of an orogastric tube into the stomach via the oesophageal tube has been shown to correlate with optimal anatomical airway positioning over the larynx.

34. ADVANTAGES Increased airway seal improves the PPV. Decreased chance of aspiration- 1.Oesophageal opening is isolated from the airway. 2.Drain tube vents gas leaked into the oesophagus . 3.On regurgitation drain tube vents the fluid & small solid particles beyond the pharynx. 4. The large bulk of the PLMA reduces the space available for regurgitated fluid to ‘pool’. 5. Increased oesophageal and pharyngeal seal decreases the risk of any pooled fluid entering the laryngeal inlet. Simple tests enable correct positioning of the PLMA to be confirmed. The stomach may be accessed with an orogastric tube.

35. DISADVANTAGES 1. Less suitable as an intubating device as an ILMA b/c narrow airway tube. 2.Slightly longer time required to insert than C-LMA. 3.Can cause airway obstruction by- compression of supraglottic structure or cuff in folding. 4.Contraindicated for intraoral surgery .

36. LMA - SUPREME Single use, PVC made 2 nd generation LMA. Has features of P-LMA, I-LMA & LMA unique. ( i ) Single use , PVC- (cf.LMA unique). (ii) Large inflatable plastic cuff, but no posterior cuff (cf. PLMA) (iii) Oesophageal drain tube (iv) Preformed semi-rigid tube (v) Fins in the mask bowl to prevent epiglottic obstruction(cf. PLMA, cLMA ) Pharyngeal seal is intermediate between cLMA and PLMA( 26–30 cm H2O) Oesophageal seal not reported.

37. ADVANTAGES The reinforced tip reduces the risk of fold-over, compared with the PLMA. Anatomic curve that facilitates easy insertion. A drain tube to allow gastric aspiration. A high volume/ low pressure cuff which generates higher seal pressure (36.1 vs 27.4cm H20 of LMA unique). A built-in bite block and fixation tab to help secure the airway 4- An oval airway cross section for improved stability of the airway DISADVANTAGES drain tube runs through the middle of the airway tube (rather than next to it in the PLMA) dividing it into two narrow lumens. This limits its use for airway inspection and for use as a conduit for intubation. Being made of PVC, the SLMA may cause more trauma than silicone devices

38. LMA C- Trach Enables combined ventilation, visualization, and intubation. High first attempt intubation success rate of 91%. Fiberoptic technology allows real time visualization of the glottic opening and of the ET tube passing through the vocal cords. Ideal in rescue/difficult airway situations . Completely portable and wireless system weighs less than eight ounces. Easy to learn and very effective

39. INSERTION Inserted exactly the same as the LMA Fastrach . Once the airway is secured and patient is being ventilated The viewer is switched on, placed in the magnetic connector and a clear image of the larynx is displayed in real time. The ET tube can be viewed as it enters the trachea. Once the patient is intubated , the viewer is removed and the mask is removed leaving the ET tube in place. Problems:- 1. It has a poorer image quality than a flexible fiberoptic endoscope. 2. It cannot be used easily in the patient with a limited mouth opening. 3. The view may be obstructed by secretions, lubricant, or blood.

40. i -GEL Novel SAD designed by UK anaesthetist, Muhammed Nasir . ( i ) Single use. (ii) Cuffless : the mask is made of a soft polymer and is shaped similarly to an inflated LMA posteriorly with its anterior shape designed to ‘fit the perilaryngeal structures’. (iii) Narrow-bore oesophageal drain tube. (iv) Short, wide-bore airway tube. (v) Integral bite block (vi) Contains an epiglottic rest at the anterior part of the cuff which reduces the possibility of epiglottis ‘down folding’ and airway obstruction.

41. Continue… Mask is made of a thermoplastic elastomer (SEBS-Styrene Ethylene Butadiene Styrene) that has the flexibility and feel of human tissue. . After placement, body heat from the patient activates the gel component of this airway which expands to fill the void in the hypopharynx where the device rests. Advantages:- 1. easy to insert: due to a combination of a very,very low coefficient of friction when lubricated & absence of cuff. 2. truncated tip, with the aim of reducing post-use dysphagia . 3. wide lumen make it well worth for both airway rescue and as a conduit for assisted intubation. 4. A gastric channel allows for suctioning and placement of a nasogastric tube. 5.Though oesophageal seal is low but enough (according to the manufacturer).

42. LARYNGEAL TUBE multiuse, latex-free, single-lumen silicon tube two low pressure cuffs (proximal and distal). The distal balloon (esophageal balloon) seals the airway distally The proximal balloon ( oropharyngeal balloon) seals both the oral and nasal cavity. Two anterior ,oval ventilating vents between the cuffs. Cough pressure 60cmH2O 4 types- LT, LT-D, LTS-II, LTs-D

43. INSERTION Open the mouth app. 3 cm using the thumb and index finger technique in neutral position of head. Hold like a pen in the area of the teeth marks (three black marks). Insert centrally along the hard palate into the hypopharynx . Advance until a slight resistance is felt. The center black line should n be level with the upper front teeth. Inflate the cuffs considering the respective colour code. Connect bag to the 15 mm standard connector. place the tube deeper, inflate the cuffs and withdraw until ventilation is optimized results in the best depth of insertion because tissue is retracted away from the laryngeal inlet.

44. SIZE VOLUME(ml) 10 1 20 2 35 2.5 45 3 60 4 80 5 90

45. ADVANTAGES Easy insertion. 2.High ventilation pressure can be used. Better protection from aspiration. Can be used to intubate the trachea. DISADVANTAGES 1.Airway obstruction. 2.Displacement on head & neck movement. 3. Cuff rupture 4. Trauma to pharynx.

46. ESOPAHGEAL- TRACHEAL COMBITUBE PVC double lumen supraglottic airway device with two inflatable balloons 2 Lumens: tracheal and pharyngeal Ventilation -either tracheal or esophageal intubation 95% of cases tube enters the esophagus Proximal balloon-seals the oral and the nasal cavity Distal balloon - seals either the esophagus or the trachea, depending on which of these the ETC has been sited. Size- 37 Fr for height up to 5 ft. 41 Fr for height above 5.5 ft. Between 5-5.5ft – either of these.

47. INSERTION Neutral position. Lift the tongue and lower jaw upward to open the oropharynx . Lubricate the tube with sterile, water soluble lubricant. Insert the Combitube so that it curves in the same direction as the natural curvature of the pharynx . If resistance is met, withdraw tube and attempt to reinsert. Advance tube until the patient’s teeth are between the two black lines. Inflate the blue pilot cuff with 100ml of air from the large syringe. Inflate the white pilot cuff with 15ml of air from the small syringe. Begin ventilation through the longer tube . If auscultation of breath sounds is good and gastric inflation is negative, continue and vice versa.

48. INDICATION Patients in irreversible respiratory arrest (i.e. narcotic overdose, hypoglycemia ). Patients in cardiac arrest. Ventilation in normal/abnormal airways Failed intubation Unconscious patients without a gag reflex, and in need of ventilatory support CONTRAINDICATION Intact gag reflex Under 4 feet tall & Under 16 years of age Conscious – arouseable patient Known esophageal disease (cancer, varices ) Ingestion of caustic substances Stoma or functional surgical airway Partial or complete FBAO CONSIDER: Latex Allergy

49. ADVANTAGES Requires minimal training May be more useful in non-fasted patients Successful passage and ventilation in many patients via esophageal route Portable, useful in remote setting Functions in either the trachea or esophagus DISADVANTAGES Only adult and small adult sizes Potential for esophageal trauma Problems maintaining seal in some patients

50. EASY TUBE The Easy Tube is new disposable, polyvinyl -chloride, double-lumen, latex-free, supra-glottic airway device. It has a close design to the Combitube , intended to be more friendly to use. Allows ventilation in either esophageal or tracheal position, however it is expected to enter the esophagus in most cases. However, the Easy Tube had a better fiberoptic view and a shorter time to achieve an effective airway, with similar ventilatory performances with the ETC

51. STREAMLINED LINER OF THE PHARYNGEAL AIRWAY Plastic made, uncuffed , disposable ,2 nd generation SAD. Anatomically pre-shaped to line the pharynx. Hollow & boot shaped distal part- Toe- rest in the oesophageal entrance. Bridge- fits to the pyriform fossa . Heel- anchor in correct position & connect the airway tube. Two lateral bulges- relieve pressure on Hypoglossal& recurrent laryngeal NV. Large capacity chamber-store regurgited fluid. Available in 6 sizes- relate to dimension across the bridge: 47, 49, 51, 53, 55, and 57 mm.

52. ADVANTAGES Easy to insert. Greater airway sealing pressure. N2O has no effect on sealing pressure- as no cuff. Effective protection against aspiration during PPV CONTRAINDICATED Upper airway abnormality.

53. CUFFED OROPHARYNGEAL AIRWAY PVC made , single use ,1 st generation. The distal cuff inflate below the soft palate, behind the tongue, above the epiglottis, and within the oropharynx . Available in five sizes: 7, 8, 9, 10, and 11 cm length with cuff inflation volume of 20, 25, 30, 35, and 40 ml respectively. Insertion like Gudel’s oropharyngeal airway. COPA is recommended for use in spontaneously breathing patients with no risk factors for aspiration. It is quick and easy to place. Easy size selection & low cost. Less airway protection

54. ELISHA AIRWAY DEVICE Silicon made , latex free, latest. three separate channels for ventilation, intubation, and gastric tube insertion. Ventilation channel (VC) and Intubation channel (IC) are side-by-side but join at the ventilation outlet situated in front of the laryngeal inlet. The VC has a standard 15 mm connector at th proximal end. The IC allows passage of an 8.0 mm ET tube for blind or fiberoptic -guided intubation. Gastric tube channel (GTC) has an outlet located in the distal end of the device.

55. Two high-volume, low-pressure cuffs. Proximal cuff seals the oropharynx and nasopharynx & distal cuff seals esophagus. Both are inflated through a single pilot port with 50 cc of air resulting in an intra-balloon pressure of approximately 70 cm H2O. Provide combination of 3 functions in a single device: ventilation, intubation (blind and/or fiberoptic -aided) without interruption of ventilation, and gastric tube insertion.

56. OTHER NEWER SAD Eldor Laryngeal Airway. Glottic Aperture Seal Airway. Glossopalatine Tube. Etc.

57. EFFICACY VS SAFETY For the evaluation of efficacy (absolute & relative ) small clinical trials can be used. Contrary, evaluations of safety ( like ventilation failure rates , more pertinently the risk of aspiration ) may need studies in larger scale with larger populations. Therefore the risk profile of a new device (unless it is particularly unsafe) is unlikely to be established for several years after introduction.

58. SUMMARY There is no solid evidence of any device performing better than the classic LMA among the first generation SADs. In the second-generation SADs- The PLMA proved top be very efficacious and safe in both routine and advanced uses SAD with a drain tube has become the first choice as the standard of care. Other newer SADs like i -gel, SLMA, and LTS-II have increasing positive evidence of their superiority. All these developments in the field of SAD paved the way to take an ever larger role in modern airway management.

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