Review of:Denver Metro Airway Study Group: “A Prospective Multicenter Evaluation of Prehospital Airway Management Performance in a Large Metropolitan Region.” Prehospital Emergency Care. 13(3):304-310, 2009.
The Science
This study from the Denver Metro Airway Study Group was organized by 18 hospitals and 34 transporting EMS agencies serving a population of 2.3 million. The goal of the study was to determine the following:
- The success rate of prehospital endotracheal intubation;
- The unrecognized tube “malposition” rate, and
- Predictors of incorrect tube position upon arrival to the emergency department (ED).
To collect this information required a considerable level of cooperation between competing hospitals groups and EMS agencies, as well as a significant commitment to collect data on every prehospital intubation attempt.
The researchers defined an attempt as “insertion of a laryngoscope with the intent to intubate or an attempt to pass an endotracheal tube (ETT) into the trachea or nostril.” The systems all required capnographic tube verification by either coloremtric or waveform method, as well as other techniques. Following each intubation, a card was filled out and given to the receiving ED physician for completion related to tube placement verification.
In all, 926 patients had an attempted intubation. Methods of airway management were determined for 97.5% (825/846) of those transported to a hospital and 33.8% (27/80) of those who died in the field. There were 150 trauma patients and 686 medical patients. For transported patients, 74.8% were successfully intubated, 20% had a failed intubation, 5.2% had an incorrectly positioned tube on arrival to the ED, and 0.6% had another method of airway management used. Incorrectly positioned tubes were significantly more common in pediatric patients (13.0%, compared with 4.0% for nonpediatric patients).
The authors concluded “Overall intubation success was low, and consistent with previously published series. The frequency of incorrectly positioned ETT was unacceptably high, and also consistent with prior studies. Our data support the need for ongoing monitoring of EMS providers practices of endotracheal intubation.”
The Street
I commend the Denver Metro Airway Study Group for taking on this phenomenal challenge. The role of prehospital intubation continues to be one of the most controversial topics of discussion in EMS. This study was well designed, and the quality of the data collected perhaps provided the authors some surprising results in that their success rates were lower than anticipated and their “malpositioned” tube rate higher than expected.
What I found striking is that 70% of the data came from run sheets and not from the data cards medics completed and provided to ED physicians at the hospital. ED physicians have been quick to criticize our performance but when given an opportunity to participate in a quality improvement initiative, they failed miserably.
Another point that must be taken into consideration with this study is that none of the intubations were performed with rapid sequence intubation (RSI) as it’s not within the scope of practice of the participating services. Would this have improved the success rate? Perhaps, since 25% of trauma intubations were unsuccessful. However, the pros and cons of this have been addressed by other studies.
Of even greater concern is the number of incorrectly positioned tubes discovered upon ED arrival. Of pediatric intubations, 13% weren’t in the trachea, compared to 4% of adult tubes.
And finally, despite being mandatory, capnography by any means was performed in only 70% of cases.
Although the authors state the obvious in their conclusion, I believe they explore more clearly in their discussion what many medical directors, me included, must strongly consider. “In light of the introduction of alternative methods of airway management techniques, we believe a better approach is to transition to these techniques and devices that ensure oxygenation and ventilation rather than focus on improving intubation success rates. Utilizing these alternative methods of airway management techniques could eliminate the need for intubation in high-risk patients for whom there is evidence of improved patient outcomes (for example, continuous positive airway pressure can be used to replace nasal intubation in chronic obstructive pulmonary disease [COPD] exacerbations).”
