(Part Two of an evidence review by Jamie Todd)
A small number of UK pre-Hospital Care Providers have trialled or used custom made devices in order to perform a large Needle, trochar or seldinger wire guided placement of a small diameter short cuffed tube through the Cricothyroid membrane. This skill was available to ALL paramedics in those regions although one service has recently with drawn these devices (Anecdotal report due to high cost and reported failures).
Most common is the Quicktrach II (VBM, 2018) and this represents a group of similar tube over large bore needle or trochar devices. Numerous studies including (Tomas Henlin, 2017) demonstrate these devices have a longer procedure time, more complications, an increased number of attempts and in some reports very high failure rates particularly in the obese. This means often the technique has to be modified and in one UK ambulance service and also in my anecdotal experience a surgical incision often has to be made to allow passage of the device at all and certainly to prevent excess force being used to penetrate the cricothyroid membrane which has the risk of puncturing the rear wall of the Larynx. (Henderson, 2018) There is also the risk with short tube devices of the tube entering the tissue layers in a laminar fashion (Again especially when a lot of force has to be used to insert) thus leading the operator to believe they have a successful placement until ventilation takes place with the result of tissue inflation and surgical emphysema.
A systematic review of multiple such devices concluded that there was little current evidence as to the superiority or success rates for each device given that the numbers reported in many papers are so small. (Langvad, 2018) Time taken to perform (Oft reported as 120-180 seconds) may also be critical in determining patient outcome where the patient was likely to have been hypoxic at the start of the procedure and may have been since the initial call to the pre-hospital emergency services.
Anecdotally in paramedic use in the emergency Pre-hospital can’t ventilate can’t oxygenate type scenario, a highly stressed situation for the clinicians involved I have heard of reported success rates from 0-50% for various devices although the numbers of procedures performed are incredibly small. This may also be partly explained by equipment familiarity, given the rarity of this procedure we are asking a clinician likely at their most stressed to use a piece of equipment that they may not have opened or used in training for some time.