Survey of supraglottic airway devices usage in anaesthetic practice in South Indian State.

INTRODUCTION

Safe, effective airway management is the foundation of quality anaesthetic practice. The classic laryngeal mask airway (LMA) is one of the airway equipments, which revolutionised airway management in the anaesthetic history. The popularity of the LMA stems from perceived benefits over other airway devices.[1] Following success and popularity of Classic™ LMA, many different variants of this device have been designed and marketed.

There is no survey of supraglottic airway device (SGAD) usage done in India. Considering the widespread usage of the LMA and its variants in India we decided to get the first-hand user details about the practice of SGADs here.

METHODS

The survey was conducted during State anaesthesia conference during 2012. Participants were informed about this survey and encouraged to participate. They were provided survey form for filling (Appendix 1: Survey on the use of laryngeal mask ariway). Inclusion criterion was all qualified anaesthesiologists participating in the conference. Trainees were excluded from the survey.

Sample size was calculated as 100 assuming usage and awareness of 80% among practicing anaesthesiologists with an error of 10%.

RESULTS

Totally 400 anaesthesiologists including 75 trainees attended the conference. One hundred and fifteen questionnaires were filled up by the attending anaesthesiologists. Fifteen questionnaires were not taken into consideration for the analysis since they were filled up by the anaesthesia resident trainees. Hence, a total of 100 questionnaires (30% response) were analysed for the results. (Table 1: Results of Survey regarding use of SGAD)

Table 1

Results of survey (regarding use of SGAD)

The overwhelming majority of respondents (83%) used reusable SGADs in preference to disposabe ones. The most common SGAD used was classic™ LMA (28%), followed by ProSeal (20%) and i-gel (18%), Fastrach (17%) and Flexible type (15%).

Propofol was the agent of choice for SGAD insertion for majority of the respondents. Eleven percentage of the respondents used thiopentone sodium as an induction agent for insertion. 23% of the respondents used classic LMA not more than 40 times. Rest of the respondents used more than 40 times, sometimes until it was no longer usable [Figure 1]. 62% of the respondents who used i-gel reused it more than once. Some used it until it was no longer usable.

Figure 1

Reuse of laryngeal mask airway

DISCUSSION

The previously published surveys of LMA usage have been done in teaching hospitals in Western countries.[23] Our survey was conducted among the anaesthesiologists who work in wide spectrum of practice ranging from small nursing home to tertiary care referral centres. The most common SGAD used was classic LMA. Majority of practitioners preferred SGAD whenever possible.

There is growing body of evidence that the LMA has very high success rates and low complication rates.[23] However, 69% of users in this survey mentioned having faced problems with SGADs. Probably the high percentage of difficulty in insertion may reflect differing criteria for successful use. We did not ask questions regarding the selection of the size of SGAD for patients.

We found out some interesting information such as majority of anaesthesiologists using anticholinergic premedication and neuromuscular blocking agents for insertion of SGAD. Conventionally, LMA insertion and use has been with spontaneous ventilation only.[4] Though it has been used for positive pressure ventilation, muscle relaxants are not necessary for insertion.[45]

As per the manufacturer's instruction, classic LMA should not be used more than 40 times by autoclaving. Only 23% of the respondents in our survey used classic LMA not more than 40 times. Rest of the respondents used more than 40 times, sometimes until it was no longer usable. This is not surprising, particularly in difficult economic scenario where the healthcare cost is mounting every passing day. At the same time, are we compromising the patient safety? In vitro work suggests the cLMA and ProSeal LMA may be reused 130 and 80 times, respectively, before failing pre-use tests recommended by the manufacturer.[6] In vivo work supports 60 reuses.[7]

CONCLUSION

This survey shows that majority of anaesthesiologists reuse i-gel. It also shows that they use the classic LMA more than the manufacturer's recommended 40 times. It might lead to compromise in patient safety and have medico legal implication.