*7.2.2 Device description, technical aspects*

The cLMA consists of the following parts (**Figure 2**):


by turning off the ventilator and closing the adjustable pressure limiting valve of the circuit. A fixed gas flow of 3 L/min is started and the pressure allowed to rise.

*LMA: laryngeal mask airway, ILA: intubating laryngeal airway, LTS: Laryngeal Tube Suction, LTS-D: Laryngeal*

**Oesophageal sealing Pharyngeal sealer Perilaryngeal sealers**

Combitube (Covidien-Nellcor

LMA Classic (Teleflex, USA)

LMA Flexible (Teleflex, USA) AuraOnce LMA (Ambu, Denmark) Aura-i LMA (Ambu, Denmark) Air-Q ILA (Mercury Medical, USA)

LMA ProSeal (Teleflex, USA)

AuraGain LMA (Ambu, Denmark)

i-gel (Intersurgical, UK)

Baska mask (Baska Versatile Laryngeal Mask Pvt. Ltd., Australia)

Cobra PLA (Pulmodyne, USA) LMA Unique (Teleflex, USA)

Rusch Easy Tube (Teleflex, USA) LMA Supreme (Teleflex, USA) VBM LTS II (VBM, Germany) LMA Guardian (Teleflex, USA) King LTS-D (Ambu, Denmark) LMA Protector (Teleflex, USA)

None (1st generation) VBM Laryngeal Tube (VBM,

*Special Considerations in Human Airway Management*

Gastric channel (2nd generation)

Gastric channel + selfenergising mechanism of

*Classification of supraglottic airways.*

seal

**Table 1.**

Germany)

USA)

b. Auscultation just lateral to the thyroid cartilage for an audible noise

c. Manometer stability test- The fresh gas flow is set at 3 l/minute of oxygen and the adjustable pressure limiting valve of the circle system is closed. As the pressure from the breathing system increases, the aneroid manometer dial is observed to note airway pressure at which the dial attains stability and no further rise in pressure is seen. A maximum pressure of 40 cm H2O is allowed.

Correct placement of the LMA can be checked by a simple test. A soap bubble solution is placed over the tip of the drain tube. If the tip of the LMA is in the laryngopharynx, bubbling or bursting of soap solution column will occur during

The original Laryngeal Mask Airway (cLMA, Intavent Direct, Maidenhead, UK) was the first SGAs introduced into clinical practice. It was invented by Dr. Archie Brain in the United Kingdom 1981 and was introduced into clinical practice in 1988.

There are various methods of assessment of OLP [62].:

a. Audible noise over the patient's mouth

*Tube Suction disposable, PLA: perilaryngeal airway.*

positive pressure ventilation.

**7.2 First generation SGA**

**256**

*7.2.1 LMA classic* ™ *(cLMA)*

• Elliptical mask

The angle between the mask and shaft is 30°. The machine end of the shaft has a standard 15-mm adapter. Two flexible vertical bars at the junction of the shaft and mask prevent obstruction of the ventilating lumen by the epiglottis (**Figure 3**). Reusable devices are constructed of medical grade silicone designed to provide an oval seal around the laryngeal inlet and act as a sleeve joint at the upper oesophagus. The single use devices have a cuff constructed of polyvinyl-chloride.

The classic laryngeal mask is available in eight sizes, as shown in **Table 2**.
