Discussion

 

 

For successful airway management (AM) in patients requiring anesthetic care, availability of adequate equipment for difficult airway (DA) management is needed. In a comprehensive survey questionnaire regarding AM, we also evaluated to which extend this need is fulfilled at anesthesia departments in Austria.

 

Study Limitations

 

The study has some limitations. The questionnaire forms were mailed to the clinical directors; their answers may not necessarily be in accordance with those of the staff anesthetists of the departments. The major limitation of this survey questionnaire may be the relatively low response rate of 66 percent restricting the accuracy of the responses. 

 

Availability of a Difficult Airway Cart

 

The recently updated and newly released guidelines and recommendations for DA management (3, 4, 14, 18) again advocate the availability of a DA cart or an equivalent unit containing alternative and evaluated devices for difficult face-mask ventilation (MV) and conventional tracheal intubation for all anesthetizing locations. In this survey, a DA cart, including at least a flexible bronchoscope (FB), for the central or main operating area as provided in 80 percent and a DA cart or an equivalent unit was available or readily accessible for all anesthetizing locations in 32 percent.       

 

In a recently published survey including only university and university-affiliated teaching hospitals in Germany (10), the availability of a DA unit was provided in only 64 percent. In a survey in Denmark, published in 2004 (16), at least one DA unit was available in 89 percent, including a FB at the main operating area in 70 percent. In a previous survey (15), Canadian anesthetists had immediate access to a DA unit and a FB in 96 and 99 percent, respectively; this favorable availability of equipment for DA management was probably the result of the early activities of the Canadian airway focus group (6).  

 

General anesthesia in obstetric patients, particularly in urgent and emergency situations, is frequently associated with difficult MV and/or conventional tracheal intubation. In 1999, the American Society of Anesthesiologists task force on obstetrical anesthesia (1) already advocated the availability of DA unit and the access to a FB for all obstetric anesthesia workstations. In this survey, a DA unit for obstetric anesthesia workstations was available or readily accessible in 48 percent, comparable to the results of a survey performed in Denmark (16).

 

Alternative Devices for Ventilation

 

Laryngeal mask airways (LMAs) and esophageal-tracheal combitubes (ETCs) were the most commonly available alternative devices for ventilation. Standard LMAs and LMAs with an esophageal drain tube, the ProSeal LMA, were available in 100 and 78 percent, respectively, significantly higher than in a survey in Denmark (16). LMAs were recommended by the Canadian airway focus group (6)] and later included in the updated guidelines of American Society of Anesthesiologists task force on DA management (3) for rescue ventilation. For these situations, ProSeal LMAs may be probably more favorable (14); as with standard LMAs, they should be immediately available for all anesthesia workstations.

 

ETCs for rescue ventilation were readily available in 78 percent; this number is high probably because many anesthesia departments, particularly at rural institutions, are also involved in regional emergency medicine services. The use of the ETC as backup device in situations of difficult/impossible MV and/or conventional tracheal intubation was already recommended by the first published guidelines for DA management (1) and also by the Canadian recommendations for the unanticipated DA (6). Unfortunably, ETCs are available only in two sizes suitable for adult patients.

 

Laryngeal tubes were provided in 40 percent; they are currently not included in published guidelines and recommendations for DA management and require further evaluations for rescue ventilation.

 

Sets for percutaneous transtracheal catheter insertion and manual jet ventilation systems and sets for percutaneous cricothyrotomy were rarely available. Although current guidelines for DA management recommend the availability of these devices (3, 4, 14, 18), it appears questionable to use less familiar invasive techniques in rare emergency situations. Anesthetists are now familiar with the use of the various LMAs also in patients with DAs; LMAs were considered to be effective in situations of difficult/impossible MV and/or conventional tracheal intubation (14) and should replace invasive techniques as primary option (5).

 

Alternative Devices for Tracheal Intubation

 

FBs were the most commonly available alternative devices for tracheal intubation and the availability was quite widespread  (in 94 pecent), but still 6 percent of the departments participating in this survey questionnaire had no access to these devices. In a survey in Denmark (16), a FB was readily accessible for anesthetists in less than 80 percent. Preference of FBs for difficult conventional tracheal intubation is consistent with a survey recently performed in the United States (8). Reliance on only flexible bronchoscopy-assisted tracheal intubation was evaluated by Heidegger and co-workers (13) in a large prospective study; when the operators strictly adhered to the protocol, most problems with difficult conventional laryngoscopy were solved in a timely manner.

 

Intubating LMAs were provided in 78 percent comparable to a recent survey performed in Denmark (16). The intubating LMA was highly recommended by the Difficult Airway Society (14), but blind insertion of the tracheal tube should be replaced by guidance with a FB (9).

 

Conclusions

 

We demonstrated that there is much room for improvements in preparatory provisions for DA management at anesthesia departments in Austria. Benchmarking with the results of this survey and refining departmental directives may contribute to improved patient care. 

 

 

References