The Laryngeal Mask Airway: Its Role in Anesthetic Practice

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The Laryngeal Mask AirwayIts Role in Anesthetic
Practice

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Laryngeal Mask Airway(LMA)

• Developed by British anesthesiolosist
• Archie Brain
• Based on careful anatomic and
• physiologic studies of human pharynx
• More effective ventilatory device
• than the face mask
• Less stimulating than the endotracheal
• tube

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Correct Insertion of Laryngeal Mask Airway
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Basic Uses

• Ambulatory surgery for healthy adults
• and children
• Short, peripheral procedures
• urologic surgery, gynecologic procedures,
• inguinal hernia repair,
• surgery on upper or lower extremities
• Patients
• should not be obese
• should have not a history of esophageal
• reflux or hiatal hernia

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Specialized Uses

• Anesthesia Outside the Operating Room
• Patients with Cardiovascular Disease
• Patients Having Neurosurgical Procedures
• Head, Neck, and Ocular Surgeries
• Pulmonary Medicine and Thoracic Surgery
• Patients with Difficult-to-Manage Airways

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• Anesthesia Outside the Operating Room
• Minor therapeutic or diagnostic procedures
• Radiation therapy, diagnostic and interventional
• radiology, endoscopy, and cardioversion
• LMA provides a better airway than face mask,
• especially in children
• LMA excludes the need for tracheal intubation.
• Eliminating the risk of subglottic mucosal damage
  
• and the possiblity of tracheal stenosis

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• Patients with Cardiovascular Disease
• In patients with coronary artery disease who
  require general anesthesia for relatively short
  procedures
• LMA insertion
• less extended cardiovasculr response
• During emergence from general anesthesia
• Maintained hemodynamic stability

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• Patients Having Neurosurgical Procedures
• Costa e Silva and Brimacombe
• Simply replacing the ETT with the LMA
• at the end of procedure
• General anesthesia? ??? ???? ??
• hypertension, coughing, and bucking??
• ???? ??? ??
• Neurosurgical repair of intracranial aneurysm,
  patients with increased intracranial pressure
• Avoid hypertension
• Hemodynamic stability
• -gtLMA may be beneficial

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• Head, Neck, and Ocular Surgeries
• Flexible LMA model
• Soft and bent easily in any direction
• Minimal interference with surgical field
• LMA ??? ??(in ophthalmic procedure)
• smooth induction
• cough free emergence
• the risk for intraocular hypertension ??
• -gt use for patient with elevated
• intraoccular pressure

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• Pulmonary Medicine and Thoracic Surgery
• Diagnostic fiberoptic laryngoscopy
• and bronchoscopy
• can be performed readily through the LMA
• (under topical anesthesia with sedation
• or under general anesthesia)
• Useful as a conduit for Nd-YAG laser
• ablation of tracheal and carinal tumor
• Useful for the placement of tracheal and
• bronchial stents
• Useful In the intensive care unit
• fiberoptic-guided percutaneous tracheostomy

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• Patients with Difficult-to-Manage Airways(1)
• In patient with a short mandible or a high and
• anteriorly displaced larynx
• intubation may be difficult or impossible
• -gt LMA frequently can be inserted easily
• ?? LMA? anatomically superior design? ??
• The LMA is intended to fit into a
  potential space
• of pharynx
• Benumof
• In patients whose tracheas cannot be
• intubated due to unfavorable anatomy
• -gt LMA should be immediately available and
• considered as the first treatment of choice

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• Patients with Difficult-to-Manage Airways(2)
• Major advantage of LMA
• adequate ventilation can be maintained
• in most patient
• Intubating LMA (LMA-Fastrach)
• specifically designed as a ventilatory device
• and as a conduit for tracheal intubation
• suitable for use in the operating room
• and in other patient care areas, such as
• intensive care and emergency medicine

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Problems and Controversies
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• Several problems
• Failed insertion
• Gastric insufflation
• Excessive airway leakage
• Pharyngeal and laryngeal trauma
• Nerve palsies
• Laryngospasm and brochspasm
• Regurgitation with or without aspiration
• Most problems
• Relate to inappropriate use, misunderstanding
• of LMA capabilities, or simply a lack of
  training
• and experience
• Significant reduction in the number of problems
• was reported when training was provided
• in an optimal learning environment

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• Controversies
• Regurgitation and Pulmonary Aspiration
• Positive-Pressure Ventilation
• Use for Prolonged Procedures

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• Regurgitation and Pulmonary Aspiration
• LMA dose not offer complete protection against
• aspiration if regurgetation of the gastric
• contents or vomiting occurs
• Risk factor
• Mobid obesity, airway difficulties, emergency
  surgery,
• and gastroesophageal reflux
• Overall risk for pulmonary aspiration
• (In 1995, Brimacombe and Berry)
• LMA approximately 2/10,000
• ETT approximately 1.7/10,000

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• Positive-Pressure Ventilation
• LMA in patients with normal lung compliance
• ???? ???? Positive pressure ventilation? ??
• Tidal volumes 68 ml/kg
• Airway pressure 1520cm H2O ? ??
• To prevent gastric insufflation and oropharyngeal
• leakage
• Ventilation through LMA Vs ETT
• No significant differences
• No difference in gastric insufflation
• when mean peak airway pressures were
• maintained at approximately 17cm H2O
• Most important factor for successful positive
• pressure ventilation
• Correct positioning the device
• select appropriately sized LMA
• use standard insertion technique

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• Use for Prolonged Procedures
• The LMA is recommended for procedures
• lasting approximately 2 or 3 hours
• Potential risk for trauma to the pharyngeal
• mucosa during extended procedures
• Recent studies
• To reduce the risk of mucosal trauma
• a associated with LMA
• LMA cuff inside pressure should not exceed
• 60cm H20
• LMA cuff pressure monitoring is recommended
• for procedures lasting more than 2 hours