Anaesthesia, 2004, 59, pages 1091–1094 .....................................................................................................................................................................................................................
Prehospital airway management in Ambulance Services in the United Kingdom* S. Ridgway,1 I. Hodzovic,2 M. Woollard3 and I. P. Latto4 1 Specialist Registrar, Department of Anaesthetics and Intensive Care, Royal Gwent Hospital, Newport 2 Senior Lecturer, Department of Anaesthetics and Intensive Care Medicine, University Hospital of Wales College of Medicine, Heath Park, Cardiff CF14 4XN 3 Senior Lecturer in Emergency Medicine ⁄ Consultant Paramedic, Department of Academic Emergency Medicine, James Cook University Hospital, University of Teesside, Middlesbrough 4 Consultant Anaesthetist, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK Summary
A postal survey of the 38 Ambulance Services in the United Kingdom was undertaken to find out what equipment is provided for paramedic crews to aid tracheal intubation and to confirm tracheal placement. The response rate to our survey was 100%. Fourteen (37%) ambulance services provided neither stylet nor bougie to facilitate difficult intubation. The laryngeal mask airway was available to 15 (40%) ambulance services. Seventeen (45%) ambulance services had use of a needle cricothyroidotomy set. Twenty-nine (76%) ambulance services had no type of device other than a stethoscope to confirm tracheal tube placement. This survey showed wide variations in the equipment for airway management available to paramedic crews in the United Kingdom. We recommend provision of a standard set of airway management equipment to all paramedic crews in the United Kingdom together with introduction of appropriate training programmes. Keywords
Intubation, intratracheal. Prehospital emergency care. Equipment; airway management.
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Correspondence to: I. Hodzovic E-mail:
[email protected] *This paper has been presented (poster presentations) at the Difficult Airway Society Annual Scientific Meeting, Glasgow, December 2003 and at the World Congress of Anaesthesiologists, Paris, April 2004. Accepted: 2 August 2004
Effective airway management is vital in the treatment of critically ill patients. Emergency tracheal intubation in the prehospital setting is an accepted definitive procedure for airway management. Ambulance paramedics are the healthcare providers in the United Kingdom (UK) who are responsible for initial airway management in the outof-hospital setting. The attendance of physicians, and in particular anaesthetists, at emergencies in the prehospital setting is not mandatory in the UK and is unusual. Paramedics intubate patients who are often not in an optimal position [1] and without the benefit of muscle relaxants in an out-of-hospital environment. Tracheal intubation is considered to be more difficult in the prehospital setting than in the anaesthetic room [2]. A study by Katz et al. [3] in the United States showed that 25% (27 ⁄ 108) of patients were found to 2004 Blackwell Publishing Ltd
have improperly placed tracheal tubes, following out-ofhospital intubation by paramedics. Another study of prehospital intubation attempts by emergency medical technicians reported intubation failure rates of 49% (50 ⁄ 103) [4]. Hussain & Redmond found that up to 85% of patients with survivable injuries who die before reaching hospital may do so because of airway obstruction [5]. Nicholl et al. reported that only 63% of attempts at intubation by paramedics are successful [6]. Success at intubation will be influenced by availability of appropriate equipment. However, there is no information available on the equipment currently provided to paramedics for airway management in the UK. It was therefore decided to investigate what equipment is made available to paramedics for airway management by sending a questionnaire to all ambulance services. 1091
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Inadequacies in equipment could then be remedied, thus leading to improvements in airway management. Methods
Table 3 Equipment available (in addition to a stethoscope) to
paramedic crews to confirm tracheal intubation. Values are number (percentage). ODD only
A postal questionnaire was sent to the Chief Executives of all Ambulance Services in the UK. Incomplete information was followed up with a telephone call. The questionnaire was designed to determine what equipment is provided for paramedic crews to aid tracheal intubation and to confirm tracheal placement.
Capnography Capnography Colorimetric only and ODD device only No aid
Ambulance 4 (11%) 2 (5%) services (38)
2 (5%)
1 (3%)
29 (76%)
ODD, Oesophageal detector device.
Table 4 Airway management devices available to paramedic
Results
crews in the UK. Values are number (percentage).
Replies were received from 35 ambulance services initially and from the remaining three services after sending a reminder, thus giving a 100% response. Devices available to paramedic crews in the UK to facilitate difficult intubation are presented in Tables 1 and 2. All 38 ambulance services had the adult curved laryngoscope. In addition, two (5%) services had the adult straight blade laryngoscope and one (3%) had the McCoy laryngoscope. The paediatric straight blade laryngoscope was available to 15 (39%) services and the curved paediatric laryngoscope was available to 8 (21%) services. Eleven (29%) services had both curved and straight paediatric blades. Four (11%) services did not have paediatric blades available. Equipment available to confirm tracheal intubation included the oesophageal detector device, capnography and colorimetric device (Table 3). In two (5%) services capnography was available for helicopter crews only and in two (5%) for ground ambulances only. In one service only a colorimetric device was available. Nine (24%) services had neither tracheal intubation aids (stylet or bougie) nor a device to confirm tracheal placement. Table 1 Tracheal intubation aids available to paramedic crews in
the UK. Values are number (percentage).
Ambulance services (38)
Stylet only
Bougies only
Stylet and Bougie
No aid
16 (42%)
3 (8%)
5 (13%)
14 (37%)
Table 2 Types of bougie available to paramedic crews. Values
are number (percentage).
Ambulance services (38)
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Multiple-use bougie
Single-use bougie
Angled tip
Straight tip
Angled tip
Straight tip
2 (5%)
2 (5%)
3 (8%)
1 (3%)
Cricothyroidotomy set Nasopharyngeal airway LMA Ambulance 32 (84%) services (38)
Combitube Needle
15 (39%) 1 (3%)
Surgical
17 (45%) 0 (0%)
LMA, laryngeal mask airway.
The results of the survey regarding additional airway management devices available to paramedic crews in the UK are shown in Table 4. One service (3%) had just the needle cricothyroidotomy kit available, whereas one (3%) had all four airway devices available. Five services (13%) had none of the above devices and one (3%) of these five had neither bougies nor stylets to aid tracheal intubation. Discussion
This survey found wide variations in the availability of equipment for airway management to paramedic crews in the United Kingdom. Equipment shortages could impair their ability to provide adequate oxygenation. Our results show that more ambulance services had the stylet available than the bougie (21 [55%] vs. 8 [21%]); and 14 (37%) had neither. Gataure et al. compared the efficacy of the bougie and stylet when used by anaesthetists in a simulated difficult intubation and showed an increased success with the multiple-use bougie [7]. Pitt & Woollard [8], from the Welsh Ambulance Service, concluded that the multiple-use bougie is of value in difficult intubations for paramedics and there appears to be only a slight risk of adverse airway events. Training with the bougie was recommended prior to clinical use [8]. When used by paramedics, however, the multiple-use bougie and the stylet gave comparable results in simulated difficult intubation in a manikin [9]. 2004 Blackwell Publishing Ltd
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Anaesthesia, 2004, 59, pages 1091–1094 S. Ridgway et al. Prehospital airway management . ....................................................................................................................................................................................................................
Fourteen of the 38 services (37%) had neither the bougie nor the stylet. Only two of the 38 services (5%) used the multiple-use angled tip bougie, which has been shown to be superior to the disposable (Portex) bougie [10, 11]. The single-use bougie is also more likely to cause trauma [12]. Paramedics at out-of-hospital cardiac arrests do not work in ideal conditions for intubation [1]. It seems probable that the use of the multiple-use angled tip bougie would increase their intubation success rates. The straight paediatric blade is recommended for infants and requires a different technique of insertion from the curved paediatric blade [13]. The latter blade is commonly used in children >1 year of age. Therefore we propose that paediatric blades, both curved and straight, should be made available to paramedic crews in the UK and suitable training should be given on manikins. All 38 services provided their paramedic crews with the curved Macintosh adult laryngoscope blade. Two of the 38 services also had the straight bladed laryngoscope and one had the McCoy laryngoscope available. A straight [14] or McCoy blade [15] may improve the view at laryngoscopy. However, extra skill and training are required for these laryngoscopes to be effective. Having a choice of blades may be confusing to the inexperienced operator. There is no evidence that suggests it is appropriate to have either the straight or the McCoy blade available for paramedics. In this survey, 76% of ambulance services did not provide any device, other than a stethoscope, for confirmation of tracheal tube placement. The clinical signs of tracheal intubation may be misleading and unreliable in the prehospital setting. In hospital anaesthetic practice, auscultated breath sounds were reported to be present in 48% of the unrecognised oesophageal intubations [16]. Confirmation of intubation and ventilation with capnography is one of the minimum standards of monitoring used by UK anaesthetists in hospitals [17]. Although a number of end-tidal CO2 devices are manufactured for use in the prehospital setting, availability may be limited by expense. In our survey, only two of the 38 ambulance services (5%) provide their ground ambulance crews with the capnograph. The oesophageal detector device, on the other hand, is cheap, simple and convenient to use [18, 19]. Furthermore, in patients with cardiac arrest the sensitivity of the oesophageal detector device in detecting correct placement of tracheal tube was reported to be 100% [20]. In contrast, the sensitivity of an end-tidal CO2 monitoring device to correctly indicate tracheal tube placement in cardiac arrest patients was only 70% [20]. The oesophageal detector device is an effective and portable device for confirming tracheal intubation [18, 21], which relies upon differences in the rigidity of the tracheal and oesophageal walls. It consists of a catheter mount connected to either a 60 ml syringe or a rubber 2004 Blackwell Publishing Ltd
bulb. Training for paramedics in its use should be mandatory. In the absence of simple aids for tracheal intubation and devices for confirmation of tracheal placement the potential for both failed intubation and undetected oesophageal placement are increased. Commonly used alternatives to ventilation via a tracheal tube are ‘bag-valve-mask ventilation’ or insertion of a laryngeal mask airway. When ventilation with facemask and laryngeal mask airway are compared, the laryngeal mask airway allows effective ventilation and better oxygenation [22]. However, only 15 of the 38 ambulance services (40%) had the laryngeal mask airway available. This device can be successfully inserted where access to the airway is limited [22] and is easy to insert even for inexperienced users [23]. Pennant & Walker found that paramedic personnel can more easily insert a laryngeal mask airway than a tracheal tube, thereby instituting effective ventilation [24]. They recommended that the laryngeal mask airway should be available in all areas where resuscitation is performed. In cases of difficult mask ventilation and unanticipated difficult tracheal intubation, the laryngeal mask airway often provides rescue ventilation [24, 25]. It is not the inability to intubate, but the failure to oxygenate that must be avoided. Needle cricothyroidotomy sets were available in 17 of the 38 ambulance services (45%). Needle cricothyroidotomy is one of the mandatory skills required of State Registered Paramedics by the Health Professions Council. However, this technique may only provide effective ventilation when used with an adjustable high pressure ventilating device [26], which are not routinely available on the UK ambulances. The availability of needle cricothyroidotomy kit to paramedic crews in the UK needs urgent re-evaluation. A recent editorial has addressed the difficulties in defining indications for transtracheal jet ventilation for anaesthetists [27]. There are wide variations in the airway management equipment that is available to different ambulance services and this does not suggest an evidence-based approach. This is clearly undesirable. A strong case can be made for including the angled tip multiple-use bougie, the oesophageal detector device and the laryngeal mask airway in the equipment available to paramedic crews in the UK. This should be combined with appropriate training programmes. Further research is needed to explore the impact of the introduction of this equipment on the prehospital management of patients. References 1 Birkinshaw R, McKinnon K, Kitching G, Ryan B. Intubation in difficult positions. Pre-Hospital Immediate Care 1998; 2: 59–62.
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