The current recommendations for basic life support (BLS) allow a chest compression only cardiopulmonary resuscitation (CO-CPR) instead of applying chest compressions and ventilation to the victim if the rescuer is not capable or willing to deliver ventilation by rescue breaths.
The main reasons stated by laypersons for not delivering rescue breaths are the fear of harming the patient and the fear of being infected by the patient’s saliva 1.
The benefit of CO-CPR compared with no cardiopulmonary resuscitation (CPR) at all has been demonstrated by several study groups 2,3. CO-CPR may also increase the overall incidence of bystander CPR, as demonstrated by a 5-year increase in Arizona from 28 to 40%. Nevertheless, the findings are controversial as other studies show a benefit for full CPR with mouth-to-mouth ventilation 4.
The correct placement of supraglottic airway devices (SADs) is proven to be easy and safe even when performed by unskilled persons 5–7. Our investigation aims to prove that laypersons can use the laryngeal tube (LT) properly after reading a four-step written instruction 8.
Materials and methods
Two sets of instructions were utilized; four-step illustrated instructions on the correct utilization of the SADs were created, along with a second matching set including the addition of short written instructions. The aim was to allow randomization (and compare the effectiveness of illustration-only instructions vs. illustration plus written instruction) (Fig. S1, http://links.lww.com/EJEM/A43).
In August 2012, visitors and patients of the central hospital of the German armed forces were recruited to participate in this trial. After giving written consent and stating that they have no medical education or any knowledge of the LT, they were randomized to one of the sets of instructions. After reading the instruction they had to select the correct size LT, properly place the tube, and deliver ventilation by mouth. Sufficient ventilation was detected by a clear chest movement. The time required for successful placement was measured as the primary goal and was measured from first turning over the instruction card to the first successfully delivered ventilation.
After the first attempt, the correct utilization of the LT was demonstrated to the participants by a member of the study team. The participants then had to perform the LT placement for a second time. Primary endpoint again was the time from turning over the illustrated instruction until the first sufficiently delivered ventilation. Following the hands-on portion of the study, the participants answered a standardized questionnaire.
Laryngeal tubes suction disposable (LTS-D) size 4±5 (VBM Medical, Sulz am Neckar, Germany) were utilized. Artificial saliva (Krankenhausapotheke, Bundeswehrzentralkrankenhaus, Koblenz, Germany) was used to lubricate the LTs. The manikin used was a SimMan (Laerdal Medical Germany, Puchheim, Germany).
Statistical analysis was performed with SPSS 14.0 for Windows (SPSS Inc., Chicago, Illinois, USA).
Categorical data were analyzed with a χ2-test to find statistical differences in success rate with regard to sex, age, and the participation in a previous first-aid course.
t-test was used to calculate statistical differences between insertion time and type of instruction (illustration only or illustration and written), age, and sex. t-test for combined samples was implied to calculate the differences between the insertion times after the first and second attempt of each participant.
The data are presented as mean±SD unless stated otherwise.
In total, 71 participants were enrolled in the study. The median age of the participants was 43 years (minimum 12/maximum 76). Forty-six percent of the participants were male, 54% female. No sex-related differences could be detected (P=0.523).
Ninety percent of the participants had already completed a first-aid course, including a BLS skill station. The mean time elapsed since the last course was 11 years (minimum <1 year/maximum 43 years). There was no significant influence of a prior BLS training (P=0.551) on the shown performance.
Eighty-seven percent of the participants stated that they would perform chest compressions if they had to; 88% of those would even perform mouth-to-mouth ventilation.
A successful placement of the LT was managed by 53.3% of the participants during the first attempt and 98% during the second attempt. The mean time until a sufficient rescue breath was 124 s (±45 s) for the first attempt. The subgroup that used the illustrated instruction with written additional instructions had a mean time of 129 s (±35 s) compared with a mean time of 117 s (±15 s) in the illustration-only group (Fig. 1).
The second attempt after practical demonstration was performed by both groups with a mean time of 11 s (±3.3 s). Specifically, a mean time of 10 s (±3.6 s) for illustration and text subgroup, and 12 s (±2.75 s) for the illustration-only group was needed to deliver sufficient ventilation (Fig. 2).
Comparing the first attempt with regard to the two different instruction methods, the difference in time was not significant (P>0.498). However, concerning the time until the correct placement during the second attempt, a statistically significant difference (P=0.023) between the two groups could be shown. An absolute saving of 1.76 s (95% confidence interval −3.28 to −0.25) was measured.
With respect to the intraindividual difference between the first and the second attempt, a significant improvement (P<0.001) was observed.
In the first attempt, the LT was introduced in the wrong way by 18% of participants. About 34% of the participants did not insert the LT deep enough. Fifty-three percent of the participants had a problem in inflating the cuffs properly.
The size of the LT according to the default body height of the manikin of 170 cm was chosen correctly by 90% of the participants. After the second attempt, 69% of the participants assessed the application of the LT as ‘easy’ or ‘quite easy’.
Seventy-five percent of the participants mentioned that they would prefer to use an LT during CPR instead of having to perform mouth-to-mouth ventilation. Ninety-seven percent of the participants stated that the placement of LTs during CPR should be included in BLS courses in the future.
The current ERC Guidelines for CPR recommend a CO-CPR performed by laypersons if they are not willing or able to deliver ventilation to a patient through mouth-to-mouth technique 9.
The present study was created to investigate the effectiveness of LT placement by laypersons, following written instructions. The intention was to find out whether it is reasonable to establish a public access airway management system comparable with the public access defibrillation system as a supplement to the BLS algorithm.
This study has shown that a proper placement of an LT is possible, even if the performing layperson is not trained in airway management. However, a skill demonstration and training should be mandatory to achieve an effective LT placement within a short period. An interruption of chest compressions is not necessary. The airway management would adhere to the recommendations of the ERC Guidelines 10.
Training increased the success rate to a level of more than 98%. In our opinion, this high proportion of successful and fast placements justifies the consideration of implementing a public access airway management system.
However, our study showed as well that written instructions only as a stand-alone education is not sufficient. The two main pitfalls were: first, the participants were surprised by how deep the LT had to be placed within the manikin’s throat, although the respective mark on the LT was accurately identified. This resulted in a number of misplacements of the LT. Second, the inflation of the cuffs was a problem (Fig. S2, http://links.lww.com/EJEM/A44). The technique for inflating the cuffs of the LT properly was not explained in the written instructions in a way all participants understood. Nevertheless, 69% of the participants described the handling of the LT as easy or quite easy.
Some limitations of our study have to be mentioned. First, of course, we used a manikin instead of an anesthetized patient to perform LT placement by untrained laypersons. There is always a difference in placing SADs in manikins compared with human beings.
Second, we enrolled only 71 persons in our study. This unfortunately resulted in a weak power of our trial.
Another fact we could not simulate properly was the individual stress level each layperson would certainly have during a real-life emergency situation. We designed this simple four-step written as well as pictured instruction, assuming that first-aid providers, who are trained in the use of the LT, can utilize it as backup information, when problems occur.
In this study, we could verify that laypersons are able to place an LT in a manikin and deliver sufficient ventilation guided by illustrated written instructions only. Furthermore, we showed that a single skill demonstration enables the participants to place the LT within the recommended time frame of the current ERC Guidelines. If mouth-to-mouth ventilation can be avoided by using an LT, delivering ventilation for CPR in this way is highly acceptable by lay participants.
As major obstacles, the correct inflation of the cuffs and the correct depth of insertion of the LT were identified. Perhaps self-sealing SADs like the IGel (Intersurgical GmbH, St Augustin, Germany) could avoid one of these problems and make the correct placement even more likely 11.
Implementing a standardized SAD training within BLS/first-aid courses seems to be as reasonable as the already implemented automatic external defibrillator training and should be advocated. The ratio of laymen performing a full CPR, compared with CO-CPR, could be increased by using SADs.
Equipment of the Department of Anaesthesiology, Bundeswehrzentralkrankenhaus Koblenz was used (airway management dummy).
Conflicts of interest
There are no conflicts of interest.
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