Proseal Laryngeal Mask Airway With or Without Introducer-tool Stabilization for Pressure Controlled Ventilation
Condition: Airway Remodeling
MeSH terms: Airway Remodeling
Study type: Interventional

Summary: 
      ProSeal laryngeal mask airway (PLMA) has become an effective alternative to tracheal tube for
      gaining airway access and for the institution and maintenance of positive pressure
      ventilation (PPV) in patients undergoing short-to-moderate duration (20-60 minutes) surgery
      under GA. The PLMA is the more preferred supra-glottic airway access device for advantages
      therein over the other SGA's, including having an option of dedicated introducer-tool (ease
      of placement), availability of esophageal opening (allows regurgitated fluid to bypass the
      airway), and reinforced main body tube (prevents luminal compression). Additionally, as
      compared to other supra-glottic airway devices, the PLMA device has been found to be more
      consistent in providing PPV to patients' lungs during GA. However, not uncommonly, PLMA
      itself is not consistent in maintaining trouble-free PPV owing to the vulnerability to
      position change, especially secondary to the rhythmic movement posited by back pressure
      during PPV. This movement vulnerability induced by PPV may be because of the size/shape of
      PLMA cuff that does fit upon placement but gets vulnerable to undue movement during PPV.

      We hypothesize that keeping the introducer-tool in position after insertion of PLMA result in
      greater stabilization of PLMA in position by minimizing the movement that occurs due to
      back-pressure effect on the cuff during positive pressure ventilation. This randomized study
      intends to evaluate whether keeping the introducer-tool in position (after PLMA insertion)
      accords greater positional stabilization to the PLMA and thereby offers greater efficacy for
      achieving adequate pressure control ventilation in paralyzed anesthetized adults undergoing
      elective surgery.
    

Detailed description: 
      Supraglottic airways (SGA) have become a standard proposition in management of the upper
      airway. These devices have suitably interposed its utility as airway conduit between the
      facemask and the tracheal tube in terms of anatomical position and degree of invasiveness.
      These devices sit outside of trachea but provide a hands-free means of achieving a gas-tight
      airway. In the year 1989, the first SGA, the classic laryngeal mask airway (C-LMA), became
      available. As time went on, additional variants of LMA came into use.

      The ProSeal Laryngeal mask airway (PLMA), introduced in 2000, is by far the most specialized
      SGA device. It comprises of four main subparts: the cuff, inflation line with pilot balloon,
      airway tube, and the gastric drain tube. All components are made of silicone and are
      latex-free. Studies indicate that size 3/4 is most preferable for adult women and size 4/5
      for adult men.

      The airway (breathing, ventilation) tube of the PLMA is shorter and smaller in diameter than
      its C-LMA counterpart. PLMA's wire-reinforced body makes it more flexible and yet resistant
      to luminal compression. The locating-strap on the anterior distal tube of PLMA prevents
      finger slipping off the tube and also provides an insertion slot for an 'introducer-tool'. An
      additional safety accessory vent under the drainage tube in the bowl help avoid secretions
      from pooling and accessing the upper airway. The PLMA has a deeper bowl than C-LMA and has a
      bite-block between the airway and drain tubes at the level of teeth to prevent device injury.

      In a correctly positioned PLMA, the cuff tip lies behind the cricoid cartilage at the origin
      of the esophagus; allows liquids/gases a bypass escape from the stomach and reduces the risk
      of gastric insufflation, regurgitation and pulmonary aspiration; and provides information
      about the PLMA position. The drain tube is designed to prevent the epiglottis from occluding
      the airway tube, thus eliminating the need for aperture bars. A gastric tube, doppler probe,
      temperature probe can be passed into the oesophagus through the drainage port.

      The PLMA also has a second dorsal cuff which pushes the mask anteriorly to provide a better
      seal around the glottic aperture.

      As per the standard guidelines, an introducer-tool (a curved, malleable, silicone-coated
      blade with a guiding handle) is used to facilitate placing an PLMA in the pharyngo-laryngeal
      slot, and helps greatly with the first-insertion placement success.

      Once in place, the PLMA offers a dependable conduit through which effective PPV can be
      instituted. Interestingly, although the PLMA placement and position adequacy has a static
      corollary to it and that the institution of PPV situates a dynamic airflow system; not
      uncommonly, there are problems to effective PPV even through an adequately placed PLMA. The
      rhythmic PPV which leads to back pressure onto the PLMA cuff often result in subtle cuff
      movements resulting in leak at the desired PPV pressure.

      Based on past clinical data in unit regarding safety of this procedure we hypothesize that
      keeping the introducer-tool in position (after facilitating insertion of PLMA) minimizes
      unwanted position changes owing to back pressure effect of PPV on the PLMA cuff, and
      therefore, would enable us to achieve and maintain adequate ventilation during GA.

      We plan this study with an objective to compare efficacy of PLMA with or without introducer
      tool assisted stabilization during PPV in anaesthetized paralyzed patients undergoing short
      to moderate duration surgery.
    

Intervention name(s): PLMA with introducer; PLMA without introducer
Intervention type(s): Device; Device
Intervention description(s): The pro-seal laryngeal mask airway (PLMA) will be inserted along with introducer tool which will be kept in-situ throughout the duration of positive pressure ventilation; The pro-seal laryngeal mask airway (PLMA) will be inserted along with introducer tool which will be removed after insertion and patient will be ventilated using PLMA without the introducer in-situ throughout the duration of positive pressure ventilation
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Patients will be randomly allocated into 2-groups. Group-1 will be the 'PLMA with Introducer' group and group-2 will be the 'PLMA without Introducer' group.
Masking: Single (Participant)
Primary purpose: Other