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Emerg Med J doi:10.1136/emermed-2012-201846
  • Original article

Prehospital anaesthesia performed in a rural and suburban air ambulance service staffed by a physician and paramedic: a 16-month review of practice

  1. David Lockey2
  1. 1East Anglian Air Ambulance, Cambridge, UK
  2. 2London's Air Ambulance, London, UK
  1. Correspondence to Dr Adam Chesters, East Anglian Air Ambulance, Marshall's Cambridge Airport, Cambridge, CRB 8RX UK; achesters{at}doctors.org.uk
  • Received 7 August 2012
  • Revised 22 November 2012
  • Accepted 26 November 2012
  • Published Online First 23 January 2013

Abstract

Introduction This paper describes the first 16-months experience of prehospital rapid sequence intubation (RSI) in a rural and suburban helicopter-based doctor-paramedic service after the introduction of a standard operating procedure (SOP) already proven in an urban trauma environment.

Method A retrospective database review of all missions between October 2010 and January 2012 was carried out. Any RSI or intubation carried out was included, regardless of age or indication. Patients who were intubated by Ambulance Service personnel prior to the arrival of the East Anglian Air Ambulance (EAAA) team were excluded.

Results The team was activated 1156 times and attended 763 cases. A total of 88 RSIs occurring within the study period were identified as having been carried out by the EAAA team and meeting inclusion criteria for review. There were no failed intubations that required a rescue surgical airway or the placement of a supraglottic airway device. For road traffic collisions (RTCs), the overall on-scene time for patients who required an RSI was 40 min (range 15–72 min). For all other trauma, the average on-scene time was 48 min (range 25–77 min), and for medical patients, the average time spent at scene was 41 min (range 15–94 min).

Conclusions We have demonstrated the successful introduction of a prehospital care SOP, already tested in the urban trauma environment, to a rural and suburban air ambulance service operating a fulltime doctor-paramedic model. We have shown a zero failed intubation rate over 16 months of practice during which time over 750 missions were flown, with 11.5% of these resulting in an RSI.

Introduction

The East Anglian Air Ambulance (EAAA) is a public-funded charity that provides two helicopter-based doctor-paramedic prehospital care teams during daylight hours to provide support to land ambulance crews across Norfolk, Suffolk, Bedfordshire and Cambridgeshire. The total population numbers covered approximately 3.2 million, and much of the area is rural. The team responds to major trauma and medical emergencies, with the latter accounting for approximately 20% of all missions. The doctors employed by the EAAA are typically senior registrars or consultants in either emergency medicine or anaesthetics. New doctors receive a period of induction during which they are supervised during all shifts by a consultant or specialist registrar in prehospital care, and are tested extensively on their knowledge and practical application of standard operating procedures (SOP).

In October 2010, the decision was taken to employ fulltime doctors and strive to provide a doctor-paramedic team on both aircraft, 7 days a week. This model replaced the previous situation in which volunteer doctors were used only if available. With the introduction of this model came a new governance structure. A governance system, which had already been in place in an urban prehospital care environment, was selected and introduced at the same time, and the first fulltime doctors were employed. New SOPs were introduced, one of which set out the delivery of prehospital anaesthesia.1 The philosophy for RSI at EAA is that patients should receive RSI on-scene if it is indicated. The techniques used should be safe, reproducible and achieve the standard set for the inhospital anaesthesia and UK prehospital anaesthesia safety guidelines. Preparation should maximise the chances of first-time intubation success, and scene times should be as short as possible. The SOP selected by EAAA has evolved in an urban prehospital trauma system, which has an experience of over 6000 RSIs and a high rate of successful intubation regardless of the experience or base specialty of the doctor.2

The SOP lists six indications for an RSI in the prehospital setting: (1) actual or impending airway failure; (2) ventilatory failure; (3) unconsciousness; (4) humanitarian indications; (5) injured patients who are unmanageable or severely agitated after a head injury and (6) anticipated clinical course. The patient is placed in a position away from direct sunlight, ideally with 360o access space. After adequate preoxygenation, a standard sequence of etomidate followed by suxamethonium is administered, and the tracheal tube is placed under direct vision and always over an intubating bougie. Following confirmation of correct tracheal tube placement, anaesthesia is maintained with boluses of morphine and midazolam, and neuromuscular blockade is continued with pancuronium. In the event of a failed intubation, there is a well-rehearsed sequence of immediate ‘drills’ to perform in order to improve intubation conditions, and after a second failed attempt, or if there is failure to adequately oxygenate or ventilate at any time, a supraglottic airway is placed, or a surgical airway is performed.

Prior to the introduction of the SOP, all current members of the clinical team underwent extensive theoretical and practical training in order to become familiar with any changes to their current clinical practice. The aim of this paper is to describe the first 16-months experience prehospital RSI in a rural and suburban helicopter-based doctor-paramedic service using an SOP already proven in an urban trauma environment. This service evaluation has been registered with the East of England Ambulance Service Audit and Research Department.

Methods

The duty crew enters detailed and contemporaneous information regarding every mission into a specifically designed database. This database (using FileMaker Pro V.11, FileMaker International, Middlesex, UK) is searchable using any one or more of the data entry variables. A check-box field is ticked on the record of any patient who required an RSI, and there is also a check-box field for ‘intubation’. Data collected is in keeping with the international consensus meeting on reporting of prehospital airway management.3

A retrospective database review of all missions that occurred between 10 October 2010 (the first day of operations with the systems in place) and 31 January 2012 was carried out. The mission database at both the operational bases was searched using the terms ‘RSI’ and ‘intubation’. The written record for all missions identified was obtained where possible. A data collection form was designed and all data entered by hand, with cross-checking of hard copies of written records. Inclusion criteria were any RSI or intubation carried out during the selected time frame, regardless of age or indication. Patients who were intubated by Ambulance Service personnel prior to the arrival of the EAAA team were excluded from the analysis, as were cases in which full records were unavailable. Data collected included information regarding the base specialty and grade of the doctor performing the procedure, the documented grade of view (using the Cormack and Lehane grading system4), the indication for RSI, any documented failed intubations and information regarding scene times. In addition, all clinicians who were active during the study period were contacted to ask if there were additional cases that may not have been added to the database.

Results

The breakdown of mission statistics during the study period is given in table 1. The team was activated 1156 times, and attended 763 cases (in 34% of cases, the team was not required and stood down before landing). Trauma accounted for a higher number of missions requiring RSI than did serious medical problems (79% vs 21%, respectively) (table 2). Road traffic collisions made up the bulk of the trauma workload (71% of the trauma cases requiring RSI). Of all the missions attended, 11.5% resulted in an RSI. There were no failures to intubate.

Table 1

Number of missions attended and RSIs performed

Table 2

Types of mission requiring RSIs completed at each base

The initial search of the database identified 95 RSIs or intubations in the study period. An additional five cases were identified which were pending entry onto the database (figure 1). On examination of the written records, nine were then excluded because these patients were all in cardiac arrest and had been intubated prior to the arrival of the EAAA team. Two cases were attended by both aircraft teams and duplicated in the database. One further case was excluded because although it appeared in the database, the written record was missing, hence, further analysis could not take place. After a comprehensive search, and after application of the exclusion criteria, a total of 88 RSIs occurring within the study period were identified as having been carried out by the EAAA team. There were no failed intubations during the study period that required a rescue surgical airway or the placement of a supraglottic airway device. All patients underwent successful placement of a tracheal tube prior to transport to the receiving hospital.

Figure 1

Identification of RSI data over a 16-month period.

The indication given for the majority of the RSIs is presented in table 3 and was ‘actual or impending airway compromise’ (n=34, 38.6%), followed by ‘unconsciousness’ (n=29, 33%) and ‘head injury with uncontrollable agitation’ (n=15, 17%). ‘Humanitarian reasons’ accounted for 4.5% (n=4), and ‘ventilatory failure’ and ‘anticipated clinical course’ both accounted for three cases (3.4% each). The majority of RSIs were carried out by doctors with anaesthetic (n=47, 53.4%) and emergency medicine backgrounds (n=40, 45.5%). One case was performed by a general practitioner (who had received advanced anaesthetic training) (n=1, 1.1%). Registrars from both anaesthetic and emergency medicine backgrounds account for 77.2% of all RSIs performed (42% and 35.2%, respectively). The remaining 22.8% were carried out by anaesthetic consultants (11.4%), emergency medicine consultants (10.2%) and a general practitioner (1.1%). This data is presented in figure 2. The view at laryngoscopy for the majority of all RSIs performed were Grades I and II (table 4). Grade III views were reported in 10 cases. Anaesthetic registrars obtained a Grade I view in 15/37 (40.5%) cases, and emergency registrars achieved 15/31 (48.4%). By comparison, anaesthetic consultants documented Grade I views in 70% of cases and, likewise, emergency medicine consultants in 77.8% of cases.

Table 3

Indications for RSI

Table 4

Laryngeal view (Cormack–Lehane) by base specialty and experience

Figure 2

Number of intubations by specialty and grade.

There was a wide range of scene times (table 5). For trauma involving RTCs, the overall on-scene time for patients who required an RSI was 40 min (range 15–72 min). For all other trauma, the average on-scene time for this group of patients was 48 min (range 25–77 min), and for medical patients, the average time spent on-scene was 41 min (range 15–94 min). Overall, the average time spent on-scene by EAAA crews who performed an RSI was 41 min.

Table 5

Average (range) times spent on-scene by type of mission in minutes

Discussion

This paper describes the case-mix and RSI profile of a physician-staffed rural and suburban air ambulance. In this retrospective study of 16 months practice of prehospital RSI delivery following the adoption of a new SOP, governance structure and crew configuration, we found that all 88 patients who underwent the intervention were successfully intubated prior to transfer to hospital. There were no failed intubations requiring a surgical airway or the placement of a supraglottic airway device. A similar review of the same SOP in the urban trauma environment found a 99.8% (399/400) intubation success rate.1 This safety rate compares favourably with a recently published meta-analysis of prehospital physician and paramedic prehospital intubation success rates.5

We have also presented data on the time spent on-scene for this group of patients who undergo an RSI. The average scene time of 41 min is approximately made up of 20 min from the arrival of the team to the delivery of the anaesthetic, and 20 min to then depart from the scene. There is a wide range of all scene times presented, and this reflects the individual nature of the cases encountered in prehospital care. We split the trauma cases into RTC and non-RTC trauma, in case prolonged extrications were resulting in longer scene times and skewing our data. All the EAAA clinical teams practice the delivery of an RSI regularly in an attempt to reduce scene times. The National Confidential Enquiry into Patient Outcome and Death from trauma identified that treatment and transport by a helicopter-based team compared with a ground ambulance-based team was associated with a longer on-scene time (36.9 min vs 25.3 min).6 The delivery of an RSI by a prehospital care team may be considered to be one or the more time-consuming advanced interventions, thus, the average figures presented by us are in line with this published data. However, the use of helicopter transport of seriously injured patients to Levels I and II trauma centres, compared with ground services, has been associated with improved survival to hospital discharge.7 A robust bypass policy allows the safe aeromedical transport of seriously ill and injured patients to the most appropriate hospital.

Conclusion

This study demonstrates the successful introduction of a prehospital care SOP already tested in the urban trauma environment, to a rural and suburban air ambulance service operating a fulltime doctor-paramedic model. We have shown a zero-failure intubation rate over 16 months of practice during which time over 750 missions were flown with 11.5% of these resulting in an RSI.

Footnotes

  • Contributors AC had the idea for the service evaluation, performed data collection and analysis, and wrote the final manuscript. NK performed data collection and analysis, and contributed to the final manuscript. JM and DL assisted with data analysis, and contributed to and reviewed the final manuscript.

  • Funding None.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

References

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Poll

Among patients with minor TBI (GCS 13-15) getting CT scans ≥ 24 hours after injury, what proportion have a traumatic finding?

Results

0.5% - 43% response rate
3% - 41% response rate
10% - 16% response rate

Related original article: PCT head imaging in patients with head injury who present after 24 h of injury: a retrospective cohort study