Respiration and The Airway With Laryngeal Masks
Condition: Supraglottic Airway Devices
Study type: Observational

Summary: 
      Baska® mask (Proact Medical Systems, Frenchs Forest NSW, Australia) is displayed in figure 1
      which is the latest addition to an array of supra-glottic airway devices in clinical use. It
      has a non-inflatable cuff, which is moulded to take up the shape of the supraglottic airway,
      potentially reducing the risk of oropharyngeal tissue and/or nerve damage induced by cuff
      over inflation, a known complication with other supraglottic airways. However, the cuff
      differs from other non-inflatable cuffs in that it is continuous with the central channel of
      the device. As the pressure increases with positive pressure ventilation ,the cuff itself is
      inflated which may improve the seal so reducing leak and make ventilation more efficient. The
      Baska mask has two ports (one for venting and other for gastric tube insertion ), so it
      incorporates an inlet that fits into the upper oesophagus and the dorsal surface of the cuff
      is moulded to direct any oropharyngeal contents away from the glottis and towards the side
      channels to which suction can be attached to facilitate aspiration of this space. These
      features may reduce the risk of pulmonary aspiration of secretions or gastric contents that
      accumulate in the supraglottic area. In addition, there is integrated bite-block, which
      reduces the risk of patients biting and blocking the airway. There is insertion tab which is
      an extended hand-tab attached to the cuff that permits the operator to control the degree of
      flexion of the device during the insertion. The Baska® mask is inserted in the neutral head
      position, which may reduce the need for neck manipulation. Initial experience with Baska®mask
      has demonstrated it to be a suitable airway device for procedures less than 2 hours or when
      endotracheal intubation is not required.

      I-gel airway (Intersurgical Ltd, Workingham, Berkshire,United Kingdom) is displayed in figure
      2 which is second generation supraglottic airway devices (SADs) that was introduced in 2007.
      The I-gel is a single use (SADs) composed of a soft ,gel-like, non-inflatable cuff made from
      a thermoplastic elastomer. It has a widened , flattened stem with a rigid bite block that
      acts as a buccal stabilizer to reduce axial rotation and mal-positioning and a port for
      gastric tube insertion. It is a latex free device that does not require digital insertion
      into mouth of patient. With an epiglottic rest and wider and shorter stem, the I-gel gives an
      optimal view of the glottis with a fiber- optic scope so a shorter tube is ideal for
      endotracheal tube placement. Moreover, I-gel can be inserted as fast as classic LMA
      (Laryngeal Mask Airway) with adequate ventilation in patients and has no major airway
      complications. Therefore, it could be a good alternative to classic LMA in emergency airway
      management or general anesthesia.
    

Detailed description: 
      The study will be carried on adult female patients to reduce variability in size of the
      chosen device to enable the investigators to analyze the performance parameters of the two
      devices with greater authority. The study will be done on anesthetized paralyzed adult female
      patients undergoing elective gynecological operations that require neuromuscular block but
      not necessarily tracheal intubation. The investigators will recruit 60 adult female(18-55
      years old, ASAI&II) patients to a prospective randomized crossover clinical trial. Patients
      with history of upper respiratory tract infections, obstructive sleep apnea , potentially
      full stomach( trauma, morbid obesity BMI> 35, pregnancy, history of gastric regurgitation and
      heart burn), those with esophageal reflux (hiatus hernia), and those of coagulation disorders
      will be excluded from the study. All patients will be assessed pre-operatively El-Ganzouri
      airway score to assess the expected difficulty of intubation and patients with airway scores
      ≥ 5 will be excluded from the study.The patients will be randomly allocated into two
      groups(the Baska Mask group & the I-gel group; each group is 30 patients) using computer
      generated program . An online randomization program (http://www.randomizer.org) will be used
      to generate random list and to allocate patients into the study groups. Random allocation
      numbers will be concealed in opaque closed envelops. The patient and investigator assessing
      study outcomes will all be blinded to the study groups allocation.
    

Intervention name(s): Baska Mask; I-gel
Intervention type(s): Device; Device
Intervention description(s): used in adult low risk females undergoing elective gynecological operations; used in adult low risk females undergoing elective gynecological operations
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        adult female patients undergoing elective gynecological operations.
      
Keywords: Anesthesia, General; Baska; I-gel