Macintosh laryngoscope effective tool to align I-gel to secure airway in patients under GA

Researchers have found in a new study that compared to the conventionally used blind insertion technique, the readily available Macintosh laryngoscope could be used as a clinically useful and cost effective tool to ensure proper alignment and function of I-gel™ , when used to secure the airway in patients under general anaesthesia.

In the arsenal of anesthesiologists engaged in airway management, supraglottic airway (SGA) devices are a well-established device. I-gel (Intersurgical, Wokingham, Berkshire, United Kingdom) is a second-generation supraglottic airway device that has a cuffless perilaryngeal sealing mechanism. It is simple to implant with low danger of tissue stress, and its biting block and strengthened tip create a more patent airway. I-gel and other SGAs are most often inserted using the blind insertion method described by Brain. Malpositioning of the SGA may result in a number of problems, including stomach insufflation, increased risk of aspiration, inadequate tidal volume, air leak, airway blockage, blood staining of the device, tissue damage, and nerve injury.

A recently published research investigated the effectiveness of the Macintosh laryngoscope in increasing the success rate when I-gel is used to secure the airway.

Included were 156 adult patients who were scheduled to have elective surgery under general anesthesia. All subjects were randomly split into two groups; I-gel was placed using a blind method in group A and a Macintosh-guided approach in group B. The major purpose of the research was to assess the incidence of ideal placement in both groups based on the glottic view score obtained with a fiberoptic bronchoscope. Also compared were the oropharyngeal leak pressure, hemodynamic parameters, and insertion characteristics. Categorical data were shown as ratios or percentages, whereas continuous data were displayed as means standard deviations or medians (95 percent confidence interval). The relative risk ratio was used to determine the degree of relationship between insertion method and the anatomical fit of the device. The laryngoscope-guided insertion group had considerably higher fiberoptic scores than the blind insertion group (P 0.0001). The incidence of malposition was 3.85% in the laryngoscopic insertion group and 39.4% in the blind insertion group (P 0.0001), respectively. Oropharyngeal leak pressure was significantly greater in the laryngoscope-guided insertion group compared to the blind insertion group (P 0.0001): 26.89 3.37 cm H2O against 24.50 3.00 cm H2O. Other insertion features, except insertion time, were similar across the two groups.

The results of our study indicate that there is a 39.74 percent risk of suboptimal positioning of I-gel when I-gel is inserted using the standard blind insertion technique, compared to only 3.85 percent when the same is inserted under vision using a Macintosh laryngoscope, indicating a relative risk of less than 1, or an 86.98 percent reduction in the risk of suboptimal positioning.

Moreover, the laryngoscope-guided approach generates higher OPLP values, indicating a substantial improvement in the anatomic fit and airway seal of the device. The easily accessible Macintosh laryngoscope might be utilized as a therapeutically helpful and cost-effective instrument to guarantee appropriate alignment and function of I-gel when used to secure the airway in patients undergoing general anesthesia.

Reference –

Vyas, Ankit; Bihani, Pooja; Jaju, Rishabh1; Paliwal, Naveen,; Tak, Mathura L.; Choudhary, Usha Comparison of the efficacy of Macintosh laryngoscope-guided insertion of I-gel™ with the conventional blind insertion technique – A randomised study, Indian Journal of Anaesthesia: June 2022 - Volume 66 - Issue 6 - p 449-455

doi: 10.4103/ija.ija_192_22