Does a 4 diagram manual enable laypersons to operate the Laryngeal Mask Supreme®? A pilot study in the manikin

Abstract

Background: Bystander resuscitation plays an important role in lifesaving cardiopulmonary resuscitation (CPR). A significant reduction in the "no-flow-time", quantitatively better chest compressions and an improved quality of ventilation can be demonstrated during CPR using supraglottic airway devices (SADs). Previous studies have demonstrated the ability of inexperienced persons to operate SADs after brief instruction. The aim of this pilot study was to determine whether an instruction manual consisting of four diagrams enables laypersons to operate a Laryngeal Mask Supreme® (LMAS) in the manikin.

Methods: An instruction manual of four illustrations with speech bubbles displaying the correct use of the LMAS was designed. Laypersons were handed a bag containing a LMAS, a bag mask valve device (BMV), a syringe prefilled with air and the instruction sheet, and were asked to perform and ventilate the manikin as displayed. Time to ventilation was recorded and degree of success evaluated.

Results: A total of 150 laypersons took part. Overall 145 participants (96.7%) inserted the LMAS in the manikin in the right direction. The device was inserted inverted or twisted in 13 (8.7%) attempts. Eight (5.3%) individuals recognized this and corrected the position. Within the first 2 minutes 119 (79.3%) applicants were able to insert the LMAS and provide tidal volumes greater than 150 ml (estimated dead space). Time to insertion and first ventilation was 83.2 ± 29 s. No significant difference related to previous BLS training (P = 0.85), technical education (P = 0.07) or gender could be demonstrated (P = 0.25).

Conclusion: In manikin laypersons could insert LMAS in the correct direction after onsite instruction by a simple manual with a high success rate. This indicates some basic procedural understanding and intellectual transfer in principle. Operating errors (n = 91) were frequently not recognized and corrected (n = 77). Improvements in labeling and the quality of instructional photographs may reduce individual error and may optimize understanding.

Figure 1

Laryngeal mask Supreme^® and indicator labels. BMV ISO connector and estimated depth of insertion (mouth) were labeled red.

Figure 2

Instruction sheet. Four diagram instruction manual. Essential steps of insertion are presented in chronologic order (1-4) and manual maneuvers highlighted with red arrows and "close-ups". Key commands were shown as speech balloons. Picture 1: "recline the head"; Picture 2: "insert the device up to the indicator label"; Picture 3: 20 ml of air; Picture 4: compress the bag valve 5 times; chest will rise and fall.

Figure 3

Number and origin of errors and individual correction. Data are numbers.

Figure 4

Time to insertion and gender. No significant difference was found between genders in time to insertion. Data are mean ± SD.

Figure 5

Rate of success and previous BLS education. Data are presented as percentages. No significant difference was found between. BLS providers and participants without BLS training (P = 0.84).

Figure 6

Participant's classification with regard to school and faculty. Data are total numbers.