Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
1 A critical review of endotracheal intubation: the ‘gold 2 standard’ of airway management in out-of-hospital’ 3 cardiac arrest? 4 ABSTRACT 5 For a patient in out-of-hospital cardiac arrest, the unobstructed supply of oxygen to 6 their lungs is of paramount importance. The clear flow of oxygen is achieved by airway 7 management. Tracheal intubation has long been perceived to be the gold standard of 8 airway management however evidence now suggests that this may no longer be the 9 case. The following project aimed to assess whether tracheal intubation remains the 10 gold standard. The project has reviewed a wide range of literature from varying 11 international sources and has discussed the major issues that they raised. The 12 discussion came to the conclusion that endotracheal intubation remains the gold 13 standard for quality of airway management once placed into the airway. However, this 14 is only the case when intubation is performed by a doctor and paramedic team. 15 Significant changes to training and pre-hospital practice are required, to ensure 16 endotracheal intubation remains the gold standard when performed by paramedics in 17 isolation. 18 19 INTRODUCTION 20 Emergency medicine is concerned with the treatment of acute illnesses and providing 21 immediate care to patients to stabilise them. The Emergency Medical Services (EMS) 22 provide this care in the pre-hospital setting. Emergency medical care in the United 23 Kingdom has reached a point of great change. In response to the Keogh review 2013, 24 aspects of emergency care will be centralised to large major trauma centres. Alongside 25 this, growing awareness of the importance of pre-hospital care will raise questions 26 about established methods of working. 27 The initial treatment of cardiac arrest is one such medical emergency the EMS will be 28 involved with. As part of the treatment of cardiac arrest the emergency medical 29 personnel aim to ensure a consistent flow of oxygen to the lungs. This is achieved by 30 the process of airway management. 31 In medicine, constant review and development is required to ensure optimal patient 32 care. This is the case with airway management as two main alternative methods are 33 used. The original method of endotracheal intubation and the more recently 34 introduced supraglottic airways. 35 In recent years the long presumed gold standard of airway management, endotracheal 36 intubation, has been questioned. The debate continues on an international scale and 37 in the following discussion evidence has been drawn on from across the global 38 resuscitation community. Ultimately a successful outcome for the patient is survival. 39 Therefore the objectives for this discussion became firstly to investigate the main 40 methods of airway management; discussing their advantages and disadvantages. The 41 secondary aim is to investigate the effect of the medical personnel involved on the 42 outcome of cardiac arrest treatment. It will be seen that other questions arise during 43 the project, concerning medical training. The discussion can be summarised by asking 44 the research question: “Is endotracheal intubation still the gold standard of airway 45 management for patients in out-of-hospital cardiac arrest?” 46 47 REVIEW & DISCUSSION 48 The biological and physical issues with ETI 49 To investigate the methods of airway management available, it is necessary to explore 50 the potential flaws which they may have. When any procedure is performed, one must 51 consider the possibility of problems that may occur both during and after the 52 procedure. For the purposes of this discussion it is necessary to classify the problems 53 of ETI under various sections to include: iatrogenic harm, oesophageal intubation and 54 time taken to place the endotracheal tube. Endotracheal intubation is a highly invasive 55 procedure and as such, this leads to the potential for complications. When combined 56 with the high-risk nature of treating out-of-hospital cardiac arrest, these problems can 57 be exacerbated. 58 Firstly one must acknowledge the potential for airway trauma when placing a hard 59 plastic tube into the trachea. Iatrogenic harm can occur to a number of places during 60 ETI including the vocal cords and the nasal passages. The most serious cases of airway 61 damage, those concerned with lacerations of the trachea, have been documented in 62 studies (Minambres et al., 2009). Despite being rare, they occur more regularly in the 63 performance of emergency intubation and must be included as a potential worst-case 64 outcome (Minambres et al., 2009). E. Minambres et al. in their meta-analysis state: 65 “Emergency intubation is the principal risk factor, increasing the risk of death 66 threefold compared to elective intubation (Minambres et al., 2009).” This quote refers 67 to the risk of post-intubation tracheal rupture. 68 A second consideration regarding intubation for out-of- hospital cardiac arrest should 69 be the unrecognised misplacement of the endotracheal tube. Tube misplacement can 70 result in the tracheal tube being placed too far into the lungs and entering one of the 71 bronchi. This would lead to aeration of one lung whilst the other receives little oxygen. 72 Although any form of tube misplacement is not a desired scenario, the risk of harm to 73 the patient is greatest when oesophageal intubation occurs. The unrecognised 74 misplacement of a tube in the oesophagus will cause the patient to return to the state 75 of hypoxia that airway management attempts to alleviate. Due to the fact that oxygen 76 from the endotracheal tube is now being supplied to the stomach instead of the lungs. 77 With the near total lack of oxygen to the brain and muscles, cell death is accelerated 78 and the patient’s already critical condition could potentially become irreversible and 79 fatal. This however is not the only risk; the likelihood of gastric aspiration also 80 increases. This is because oxygen is now inflating the stomach which distends it and 81 risks gastric fluid running back up the oesophagus and into the trachea. 82 protection that the tube did offer when placed correctly is also negated. 83 If gastric fluid enters the lungs, the patient is at risk of developing aspiration 84 pneumonia because of lung damage caused by the stomach acid and the pathogens 85 present in the fluid. 86 To summarise the threat of an oesophageal intubation to a patient, it is necessary to 87 turn to the study of M. Jemmett et al. This study clearly demonstrates the extent to 88 which an oesophageal intubation threatens the patient’s survival and impedes the 89 advanced life support process. 90 “Even inefficient bag-valve-mask ventilation is still superior to unrecognized 91 oesophageal placement of an endotracheal tube.” (M.Jemmett et al., 2003) 92 The third ETI problem is of a physical nature. Any invasive procedure needs to be 93 performed with suitable accuracy to prevent harm, whilst also paying regard to the fact Any 94 that the faster ventilation can be achieved, the better the outcome of the patient. This 95 was shown by the study of K.Kajino et al. that indicated; increased time from cardiac 96 arrest to placement of airway device led to decreased survival (K.Kajino et al., 2011). 97 This study however did not investigate a crucial factor in the use of ETI, the quality of 98 cardiopulmonary resuscitation (CPR) during OOHCA. 99 CPR chest compressions act as a replacement to the regular heartbeat of a patient 100 during cardiac arrest and thus should be maintained to a sufficient standard 101 throughout treatment. In the words of the ERC guidelines on basic life support “the 102 perfect solution is to deliver continuous compressions…” (J.P.Nolan et al., 2010) and 103 the latest ERC guidelines emphasise the fact that any intervention should minimise 104 the interruption of chest compressions to no more than ten seconds (C.Deakin et al., 105 2010). ETI has a large disadvantage in this respect when compared to SGA, ETI 106 requires longer to achieve successfully. As seen in the study of 2005, by C.Deakin et 107 al., which shows the mean time of insertion for the LMA to be 47 seconds compared to 108 an average of 52.0 seconds for the insertion of ETI (C.Deakin et al., 2005). Analysis of 109 the highest time taken for each individual method is perhaps more useful to 110 demonstrate a potential worst-case scenario. The time taken for insertion of SGA was 111 126 seconds however for ETI the longest time was substantially higher at 148 seconds 112 (C.Deakin et al., 2005) . When you recognise that the study was carried out on patients 113 undergoing elective surgery the figures present more reason for concern. Deakin et al. 114 go on to state, “It is probable that performance in the field is less successful” (C.Deakin 115 et al., 2005). In the pre-hospital setting many factors such as: situation, lack of access 116 to the airway or bystander pressure, could combine to further increase the time taken 117 for ETI to be successful, thus leaving a patient not only without oxygen but also 118 without a substitute for their heart. The interruption to CPR is one factor that 119 confronts the idea that ETI is the gold standard of airway management. It could be 120 argued that the time taken to insert an endotracheal tube could be more worthwhile to 121 a patient if used for CPR and the use of a SGA would allow this to occur. 122 Other factors such as operator technique and the personnel performing intubation also 123 affect the time taken to place an endotracheal tube. These will be reviewed later in the 124 discussion. 125 Problems associated with supraglottic airways 126 So far the focus has been on endotracheal intubation, the perceived gold standard of 127 airway management and the problems it can cause. However, of equal importance are 128 any problems with the alternative methods of airway management. As mentioned in 129 the literature review, the SGA sits above the tracheal entrance as opposed to the 130 endotracheal tube, which sits in the trachea above the bronchi. This means that the 131 oxygen delivery is less direct using an SGA and therefore less efficient. The inefficient 132 oxygen delivery of the SGA is compounded by its lower sealing pressure when 133 compared to a cuffed endotracheal tube (JRCALC, 2008). Leakage from the SGA can 134 occur, potentially leading to gastric inflation due to oxygen entering the oesophagus. 135 The lower sealing pressure also means dislodgement is more likely and with 136 dislodgement comes a risk of trauma. In the hospital setting this problem can be 137 avoided somewhat as patient transportation can be kept to a minimum. In the case of 138 OOHCA the problem can be more severe as the patient must be moved as quickly as 139 possible to more advanced medical care. The LMA has been shown to cause airway 140 trauma whilst being placed and in rare cases has been associated with oesophageal 141 rupture. The risk of airway trauma can be reduced, with certain SGA giving a better 142 performance when investigated in trials (JRCALC, 2008) . 143 Advantages of ETI 144 The discussion thus far has focussed on the negative aspects of both methods of airway 145 management. The next stage of the discussion aims to investigate the benefits to the 146 patient of both ETI and SGA. 147 It is essential to remember that the primary role of airway management is to provide 148 a clear route for ventilation to the lungs. Delivery of oxygen to the lungs should be of 149 the highest priority. ETI is widely regarded to achieve the strongest ventilation and the 150 most efficient oxygen delivery to the lungs compared to other methods (J.P.Nolan et 151 al., 2010). This is due to the fact that the tube is placed inside the trachea thus 152 delivering oxygen into the airway at a greater depth. A second advantage is that correct 153 placement of the endotracheal tube allows CPR chest compressions to continue 154 without interruption. It enables a medical professional to solely focus on chest 155 compressions without the need to stop and manually ventilate a patient. 156 Improved protection from gastric aspiration is another advantage of ETI. The 157 endotracheal tube sits deeper inside the airway than an SGA and therefore it offers a 158 better seal against regurgitated gastric fluid. This will lower the risk of developing 159 aspiration pneumonia, if resuscitation is successful or damage to the airway caused by 160 gastric fluid. 161 ETI also gives the ability to insert a suctioning tube into the lungs of a patient. This 162 can be exceptionally useful in cardiac arrest as fluid may build up in the lungs of a 163 patient due to congestive cardiac failure. If it were not possible to suction fluid away 164 from the lungs then the patient would have limited gaseous exchange and ventilation 165 would be less effective in delivering oxygen to the blood. 166 The overall advantage of ETI has been indicated in the trial of H. E. Wang et al. 167 “Compared with successful SGA insertion, successful ETI was associated with 168 increased survival to hospital discharge with satisfactory functional status” (H.E.Wang 169 et al., 2012). This has been echoed in the study conducted by S.Tanabe et al. in Japan, 170 which indicates that ETI is significantly better than SGA devices (S.Tanabe et al., 171 2013). Arguably the most compelling evidence the study provides indicating that ETI 172 is a stronger option, is the data regarding return of spontaneous circulation (ROSC). 173 The study showed that the rate of ROSC was 7.24% in ETI cases compared to a greatly 174 reduced rate of 4.90% for cases using LMA (S.Tanabe et al., 2013). It could be argued 175 that this data is more useful as the measured ROSC was always accounted for before 176 hospitalisation (S.Tanabe et al., 2013). ROSC allows oxygen to be transported around 177 the body and metabolic waste to be removed. If ETI can achieve this rate of pre- 178 hospital ROSC, it could be clearly argued to be the gold standard. 179 Advantages of supraglottic airways 180 A major advantage of supraglottic airways is the speed at which they can be placed, as 181 described above. This speed could be argued to outweigh the benefit that ETI gives 182 when protecting the airway. In the words of C.Deakin et al., “Hypoxia is likely to be a 183 far larger contributor to morbidity than aspiration of gastric contents” (C.Deakin et 184 al., 2005) . Essentially saying survival depends on efficient oxygen delivery. 185 This means the speed at which the SGA can be placed could outweigh the lack of 186 protection from aspiration it provides. Therefore achieving ventilation as quickly as 187 possible could lead to a decrease in patient morbidity. C.Deakin et al. proceed to 188 discuss that hypoxia itself increases the chance of gastric aspiration (C.Deakin et al., 189 2005) . If one could prevent hypoxia then the threat of gastric aspiration could be 190 significantly reduced. However it must be remembered that ETI offers improved 191 protection and ventilation thus reducing hypoxia alongside risk of gastric inflation. 192 193 THE PERFORMANCE OF AIRWAY MANAGEMENBT TECHNIQUES 194 The biological importance of the actual airway management technique has been 195 thoroughly discussed above. Both points of view have been looked at with regard to 196 the actual biological performance of both of the suggested methods. However the 197 discussion has only briefly mentioned the medical personnel that are performing 198 airway management. It is equally important when investigating which method is the 199 gold standard to systematically review the training, the success and the failures of the 200 personnel performing ALS. The method of airway management relies on the technique 201 of the person who performs it. The literature review showed that the personnel 202 involved in ALS would vary dependent on the situation. To begin with it would be 203 worthwhile discussing the most common occurrence; intubation by paramedics. 204 Paramedic intubation 205 The first clear area of discussion is with regard to the training that paramedics receive 206 for airway management. During IHCD training 25 intubations are required of which 207 only 5 have to be unassisted. The critical reassessment of ambulance service airway 208 management in pre-hospital care, suggests that the number 25 is entirely arbitrary and 209 has no clinical reasoning (JRCALC., 2008) . This number becomes increasingly 210 worrying as the learning curve for intubation is investigated. 211 The learning curve for any skill aims to show the number of repeat performances 212 required in order to become competent in that given skill. Again it is necessary to turn 213 to Japan to investigate the most recent research in the field. The work of Toda et al. 214 indicated that after 30 intubations on patients undergoing elective surgery the success 215 rate was at 87% (S.Toda et al., 2013). 216 However, figure 1 shows that the learning curve is clearly flattening at this point. A 217 success rate of around 90% whilst being high is unacceptable in such a procedure, 218 which can have such serious complications (M.Jemmett et al., 2003). 219 220 221 222 223 224 Figure 1- A graph showing the learning curve for paramedic intubation by 32 225 paramedics in Japan (S.Toda et al.,2013) 226 227 The study can then be quoted as saying “The frequency of complications remains at a 228 high level even after training. It is desirable to conduct a more detailed and rigorous 229 assessment of the benefit of pre-hospital intubation that controls for the skill level of 230 paramedics” (S.Toda et al., 2013) . This quote shows the dangers of intubation when 231 performed by paramedics. The view of the study is clear, we cannot accurately 232 understand the precise number of intubations required to become “competent”. At 233 current, medical personnel may be undertaking a procedure of which the training 234 required is not truly understood. This argument becomes ever more apparent when 235 compared to the research of Konrad et al., which aimed to create a learning curve for 236 the skills learnt by anaesthesia trainees. At the 25 intubations required in IHCD 237 regulation, the trainees had only reached a success rate of 70% (C.Konrad et al., 1998) 238 . To achieve the same level of success as the above study the trainees required an 239 average of 57 attempts at intubation (C.Konrad et al., 1998). It is worth considering 240 that these anaesthetics trainees were intubating patients on a more regular basis than 241 the paramedics above. 242 If we assume that the learning curve for this study is a potential worst-case scenario 243 then paramedics today are receiving insufficient training in the procedure of 244 endotracheal intubation. The number of intubations required by paramedic training 245 regulation is under half that of the average number required to achieve 90% success 246 rate in Konrad’s study. In addition, paramedics are not involved with the more 247 advanced anaesthetic procedures, also seen in the study. These advanced procedures 248 will undoubtedly improve the skillset of the practitioner. However, if the training for 249 supraglottic airways is also insufficient then overall neither process would have an 250 advantage. This is not the case; supraglottic airway insertion requires little training in 251 comparison with ETI. The procedure is far less invasive and SGA insertion does not 252 require the need for laryngoscopy, a technique which takes time to master. 253 It must be remembered that training is not solely based on the initial level of success 254 of a practitioner. The time it takes for a skill acquired to fade is equally important and 255 the opportunities for the skill to be used should be discussed. The Critical 256 Reassessment for Ambulance Service airway management makes its views clear by 257 stating “Skill fade is faster with more complex tasks” before concluding to say that the 258 skill fade is faster with ETI than with SGA (JRCALC, 2008) . The research of Reutzler 259 et al. investigated the skill retention after 3 months of paramedics who were newly 260 introduced to the techniques of airway management (Reutzler et al.,2011) . Initially 261 the success rate of intubation was at 78%, with the SGA insertion rate being 100% for 262 5 out of 6 of the supraglottic airway devices available. However after 3 months the 263 success rate of ETI dropped to 58% whilst the SGA rate remained constant (Reutzler 264 et al., 2011). This clearly indicates that the skill fade for intubation is greatly increased 265 compared to that of supraglottic airway insertion. The increased skill fade can be 266 argued to undermine the belief in ETI as a gold standard. Arguing that these 267 paramedics were very inexperienced and that skill fade may lessen for those who have 268 been operating for longer can counteract this view. Undoubtedly this would be true for 269 paramedics who are regularly exposed to intubation, perhaps by working as part of the 270 HEMS teams. 271 However, it has become clear that many paramedics in active operation perform so 272 few intubations that they could easily be considered relatively inexperienced in 273 endotracheal intubation. Paramedics in certain EMS have been shown to perform an 274 average of 1-2 intubations per annum (JRCALC, 2008) . Can something be a gold 275 standard if skill fade is such an issue? 276 The problem of skill fade could be negated if regular training was facilitated. This 277 presents further problems for ETI and advantages for SGA. The use of SGA has become 278 commonplace in elective surgery and due to this the use of ETI has diminished 279 (JRCALC, 2008) . This means that the opportunities for paramedic intubation practice 280 have become reduced whilst the chances to use supraglottic airways have increased 281 substantially. Importantly, practising intubation opens up issues of consent when it 282 occurs on a patient. Patients having anaesthesia conducted are required to consent to 283 the procedure which they are having performed in advance, for cases of non- 284 immediate lifesaving care (D.G.Bogod et al., 2006) . 285 When a training procedure is being carried out during elective surgery, additional 286 specific consent is not always required. 287 The consent to anaesthesia report details the text below as guidelines to whether 288 specific consent is needed for a training procedure: 289 “The risks and benefits of each procedure and its components, both to the 290 patient concerned and to society in general, must be considered; 291 • The harms should be minimised as much as possible, e.g. by close supervision, 292 prior practice on manikins, etc.; 293 • The benefits should be maximised as much as possible, e.g. by close 294 supervision, and targeting skills to practitioners most likely to use them in the 295 future; 296 • Alternatives should be considered, e.g. other ways of learning/maintaining 297 skills, other techniques.” (D.G.Bogod et al., 2006) 298 If we consider the above for the case of training paramedics in SGA and ETI it is clear 299 which approach is more favourable and easier to achieve. ETI is a highly invasive 300 procedure when compared to SGA and therefore it is far easier to train paramedics in 301 SGA insertion. 302 The final point highlights this with the statement ‘alternatives should be considered’ 303 the difficulty of obtaining consent for ETI is limiting the ongoing training that it 304 requires. The report goes on to talk about paramedic students in particular and argues 305 that as long as the procedure is not dangerous or invasive then specific consent is not 306 required (D.G.Bogod et al., 2006). This creates the situation where the regular 307 training that is required to prevent ETI skill fade in paramedics cannot be easily 308 achieved. Whereas SGA insertion is far easier to obtain consent for and thus far easier 309 to practice. A dichotomy is created, where the harder skill is at odds with the 310 opportunities to practice it and again this suggests that ETI cannot achieve the gold 311 standard it is perceived to be. 312 Intubation by doctors and paramedics 313 Whilst intubation by a solely paramedic team is commonplace, a team consisting of a 314 doctor and a paramedic also regularly intubate patients. The addition of a doctor to 315 the emergency team is normally seen as part of a HEMS team and adds a new level to 316 the discussion. 317 It is necessary to turn to the HEMS system of Queensland Australia to investigate 318 whether a doctor does make a difference. The doctors involved were all consultants or 319 registrars in emergency medicine, intensive care or anaesthesia and would therefore 320 have had many years of training. 321 The study of Gunning et al. showed failure rate of in-hospital intubation was 0.1% to 322 0.4% whilst the failure rate of intubation in the pre-hospital setting was 2.4% 323 (M.Gunning et al., 2009) . This low figure also concurs with other studies that have 324 occurred around the world who have recorded 100% success rates (M.Gunning et al., 325 2009) . This is due to the fact that the doctor adds the experience of regularly 326 performing intubations. ETI becomes a more standard procedure when you have this 327 paramedic and doctor team. 328 Gunning et al. conclude by saying “Well-trained doctor paramedic teams… can safely 329 perform RSI and ETI in the pre-hospital and emergency environment” (M.Gunning et 330 al., 2009) . It is clear that having a doctor present has a positive effect on the outcome 331 of intubation. It can be seen that hospital standards can be brought to the pre-hospital 332 setting and that efficient and effective ventilation can be achieved. 333 334 CONCLUSION 335 The discussion has clearly shown that the question “Is endotracheal intubation still 336 the gold standard of airway management for patients in out-of-hospital cardiac arrest” 337 leads to a complex set of problems to address. 338 Firstly, one can conclude that from a biological point of view that endotracheal 339 intubation remains the gold standard for airway management. It delivers oxygen 340 deeper into the lungs than a supraglottic airway, thus ensuring that oxygen will enter 341 the circulatory system with greater efficacy. The higher sealing pressure of an 342 endotracheal tube compared to that of a supraglottic airway will reduce oxygen leakage 343 and give a stronger protection against gastric aspiration. Overall ETI achieves a faster 344 return of spontaneous circulation. 345 Secondly, with regard to time, supraglottic airways offer a quicker time of placement 346 into the airway; both in the pre-hospital setting and during elective surgery. This is 347 due to the procedure for endotracheal intubation being more complex and invasive 348 than for SGA. 349 The final area of discussion focussed on the performance of airway management and 350 this leads to the most concerning conclusion. It concluded that paramedics are 351 significantly less effective when inserting endotracheal tubes than when performing 352 supraglottic airway insertion. This conclusion can be applied with regard to time 353 taken, misplacement and damage caused. 354 It can also be seen that paramedic training is significantly responsible for this lack of 355 skill. The IHCD regulations for training were seen to be unproven and learning curve 356 analysis showed that intubation skill levels remained low after the training 357 programmes. One can also confirm that the skill fade for intubation is much greater 358 than for supraglottic airways. However, the discussion also concludes that if a doctor 359 is present whether performing or supervising, the success rate is improved. 360 Overall one can summarise that in the current pre-hospital medical situation, 361 endotracheal intubation remains the gold standard, when performed by a combined 362 doctor and paramedic team. However, currently the paramedic training, both after 363 qualification and during it, is insufficient. This needs to be improved so that the 364 benefits of endotracheal intubation can be reliably used in all cases of cardiac arrest. 365 Endotracheal intubation is the gold standard of airway management for patients in 366 out-of-hospital cardiac arrest, however the circumstances surrounding its use must be 367 improved. As part of the current changes to emergency medicine thought should be 368 given to further reassessment of the long-standing techniques of airway management. 369 To ensure optimal pre-hospital medical standards for treating out-of-hospital cardiac 370 arrest is maintained. 371 REFERENCES CITED 372 1. Miñambres, E. (2009) Tracheal rupture after endotracheal intubation: a literature 373 systematic review, European journal of cardiothoracic surgery, Vol 35,no.6, p.1056- 374 1062 375 2. Jemmett, M.E., Kendal, K.M., Fourre, M.W., and Burton,J.H. (2003) Unrecognised 376 misplacement of endotracheal tubes in a mixed urban to rural emergency medical 377 services setting , Academic emergency medicine, Vol 10,no.9 p. 961-965. 378 3. Kentaro Kajino et al Comparison of supraglottic airway versus endotracheal 379 intubation for the pre-hospital treatment of out-of-hospital cardiac arrest... September 380 2011, Critical Care. Vol 15, no.5 381 4. Nolan, J.P., et al. (2010) Pre-hospital cardiac arrest guidelines, European 382 resuscitation council. 383 5. Deakin, C., et al. (2010) Advanced adult life support guidelines. European 384 Resuscitation Council. http://www.resus.org.uk/pages/als.pdf. 385 6.Deakin, C., et al. (2005) Securing the prehospital airway: a comparison of laryngeal 386 mask insertion and endotracheal intubation by UK paramedics. Emergency Medical 387 Journal, Vol 22, no 1,p. 64-67. 388 7. JRCALC. (2008) A critical reassessment of ambulance service airway management 389 in pre-hospital care. Emergency medical journal, Vol 27, no 3, p.226-233 390 8. Wang, H.E., et al. (2012)Endotracheal 391 insertion in out-of-hospital cardiac arrest. Resuscitation, Vol. 83, no 9 pp. 1061-1066. intubation versus supraglottic airway 392 9. Tanabe, S., et al (2013) Comparison of neurological outcome between tracheal 393 intubation and supraglottic airway device insertion in out-of-hospital cardiac arrest 394 patients: A nationwide, population-based, observational study... Journal of 395 Emergency medicine, Vol. 44, no 2 ,p. 389-397. 396 10. Toda, J., Toda,A, and Arakawa, J. (2013) Learning curve for paramedic 397 endotracheal intubation and complications, The international journal of emergency 398 medicine, Vol 6. no 38, online access journal 399 11. Konrad, C., et al. (1998) 400 a recommended number of cases for anaesthetic procedure?, Anaesthesia Analgesia, 401 Vol 86, no 3, p. 635-639. 402 12. Reutzler.K, et al. (2011) 403 paramedics using seven different airway devices- a manikin study. Resuscitation 404 journal, Vol 82. no 5, p593-597 405 13 Bogod, D.G., et al. (2006). Consent for Anaesthesia- Revised Edition, The 406 association of anaesthetists of Great Britain and Ireland, London. 407 14. Gunning, M., et al. (2009) Emergency intubation: a prospective multicentre 408 descriptive audit in an Australian helicopter emergency medical service.. 1, 2009, 409 EMJ, Vol. 26, no 1, p. 65-69. Learning manual skills in anaesthesiology: Is there Performance and skill retention of intubation by