Review of: Wirtz DD, Ortiz C, Newman DH: Unrecognized misplacement of endotracheal tubes by ground prehospital providers. Prehospital Emergency Care. 11(2):213-218, 2007
This was a prospective consecutive case observational study in New York City. The researchers examined the records of all EMS patients who had been intubated in the field or were intubated within 10 minutes of arrival at their emergency department (ED). Confirmation of tube placement was determined by ED physicians who ranged from resident to attending.
During the study period, 192 patients were enrolled. Overall, 132 (69%) were intubated prior to arrival. Of these, 12 (9%) were found to be misplaced, 11 in the esophagus and one in the hypopharyngeal (just above the cords) space. They further identified 20 (15%) where the tube was in the right mainstem bronchus, but this was not considered misplacement. Only one patient with a misplaced tube survived to hospital discharge.
They concluded: The rate of esophageal misplacement of endotracheal tubes in the prehospital environment in our urban setting and the poor clinical course of patients with unrecognized misplacement is consistent with previous reports, suggesting that the benefit of prehospital airway management does not clearly supercede the potential risks.
We all agree that misplaced endotracheal tubes represent a grave risk to patients. However, does this study provide us any additional information? My first criticism of the study is the use of the ED physician assessment as the Gold Standard for tube placement. In this study, physicians were able to make the determination through a number of tests without actually placing a laryngoscope into the patient. Physicians were allowed to make the determination of misplacement based on lung sounds, gastric sounds, presence of suspected gastric contents in the tube or capnography. The ED physicians were not held to a standardized procedure.
I m not suggesting malice, but I ve seen ET tubes innocently yanked out by docs because they didn t look right when in fact I knew they were properly placed.
What this study failed to tell us was the number of attempts required by EMS for each tube, as well as what tube confirmations were used. It appears from the paper that confirmation of techniques used varied greatly.
Additionally, those patients requiring ED intubation almost always received paralytics upon arrived at the hospital. EMS documented the two primary reasons for not attempting prehospital intubation was the close proximity to the hospital and the need for induction agents.
I commend the authors for attempting to measure the tube misplacement rate in their system. However, the rate of misplacement and the intubation rate overall dropped for a period of time during the study because EMS became aware that there were being monitored. It rose later in the study but did not return to the initial baseline. Word clearly got around that the study was occurring, but the EMS providers were not notified prior to its inception.
The question of whether pre-hospital intubation is safe and, if not, what steps we need to take to make it safe can only be answered if we use a uniform dataset for airway management, such as the one designed by Dr. Henry Wang.
We need to know how many attempts were made, what types of conditions presented, what tube confirmation technique was used, and the results. We need to have verification of placement by ED physician performed using a standardized technique, such as a combination of waveform capnography and direct laryngoscopy.
Although I agree with the authors conclusion, I m not convinced this study proves it. Let s keep trying, though - our patients lives depend on it.