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Recent eLetters

Displaying 1-10 letters out of 753 published

  1. Emergency medicine: the job we're all waiting for?

    Much has been written about the current difficulties of recruiting and retaining doctors in key specialities: most recently psychiatry (1) and emergency medicine (2).

    Concurrently there has been a year-on-year decline in the number of doctors choosing to enter speciality training immediately upon finishing their FY2 year: in 2013 only 64% of FY2's chose to enter speciality training (3). Instead, many FY2's opt to work abroad, or to take trust grade positions.

    Currently, going "off-program" allows junior doctors the flexibility to develop their own skills and interests, in a way that rigidly structured training programs don't. It gives them a chance to take ownership of their own training, and to see their personal and professional development as their own responsibility, rather than an exercise in "hoop-jumping". They have a chance to work abroad, pursue additional qualifications or research, and to choose where they live and how many hours they work. They can choose to work in specialities that they didn't get to experience during the foundation program.

    As a "sessional" speciality which requires a broad portfolio of skills, and doesn't require continuity of care, emergency medicine could capitalise on juniors doctors' apparent desire to have greater flexibility and freedom in their training: trainees could be offered "half-time" contracts, which would leave them 6 months a year free to pursue other interests, degrees, or specialities.

    Similarly, a more permissive approach to offering sabbaticals, and a greater variety of less-than-full-time-training rotas would offer FY2's the best of both worlds: the flexibility associated with trust-grade work, and the support and development opportunities afforded by training jobs. Emergency departments would benefit from having committed doctors on full- time contracts, who would be guaranteed to return the following year to continue training.

    Svirko et al identified that one of the key factors repelling trainees from emergency medicine is the perceived lack of a "work-life- balance" (2): emergency departments can improve this by offering a wider variety of training contracts, to suit the different lifestyles and interests of the diverse group of doctors who are drawn to the emergency department.

    (1) Mukherjee, Psychiatric Bulletin (2013) 37: 210-214 (2) Svirko, Lambert et al Emerg. Med. J. 2014 31:556-561 (3) Foundation Programme Annual Report http://www.foundationprogramme.nhs.uk/pages/home/keydocs

    Conflict of Interest:

    None declared

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  2. Clinical Examination in place of end-tidal CO2

    Hunter and colleagues gives a good method to distinguish COPD and heart failure in a dyspnoeic patient. May i politely suggest an easier, clinical marker which can help in this distinction?

    This is based on the observation that patient who has prominent, bulging veins has COPD as the predominant cause for the breathlessness compared to the patient with heart failure who has collapsed, thready veins. The therapy can be directed accordingly and early benefits achieved using this clinical marker of distinction. Of course, this venous distension could reflect higher CO2 levels in the COPD patients. As a junior doctor, i found it much easier to cannulate these patients in emergency department compared to the congestive heart failure patients where cannulation was much more difficult.

    So, the quick clue for the acute on chronic breathless patient is bulging veins = worsening COPD, thready veins = worsening heart failure

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  3. Re: Clinical navigation for beginners: the clinical utility and safety of the Paramedic Pathfinder

    We applaud Newton et al[1] in their efforts developing the Paramedic Pathfinder tools. We feel that supporting paramedics in decision making regarding non-conveyance and use of alternative referral pathways is vital in meeting the challenges facing modern pre-hospital care, and appreciate their efforts in empowering pre-hospital staff to safely make decisions regarding such patients. However we remained unconvinced that protocolising the decision making process alone will improve the ability of pre-hospital clinicians to make the best use available resources to provide optimal clinical outcomes.

    Protocolising referral decisions is not a new concept. Snooks et al[2] investigated a protocolised approach to patients being diverted to a minor injury unit over the emergency department, and discovered no increase in the number of patients referred to an alternative point of care. Conversley, Mason et al[3] and Gray and Walker[4] identified that paramedics when given extended training in assessment, treatment and diagnostic skills were able to safely reduce attendance at the emergency department, while Clesham et al[5] showed that ambulance staff are able to correctly identify most patients that could be diverted away from the emergency department, without the need for a strict protocolised approach, if sufficient governance is in place to support them in making these decisions.

    We commend the safe approach taken by the authors in retrospectively applying the tool to patients seen by North West Ambulance Service staff. However we are concerned that this may not be generalisable to ambulance staff in other areas of the country. Recent performance data[6] demonstrated that as of April 2014 NWAS were the poorest performing Trust in the country for emergency department conveyance and calls closed via telephone triage. We would like to see the Pathfinder tools retrospectively applied to patients seen by pre-hospital clinicians in other areas of the country before stating that they categorically reduce hospital admissions, as the effect of the tools may be weakened - or even detrimental - when applied to Trusts performing stronger against these metrics. Additionally, where the patient had not been conveyed or referred to another agency, there was no follow up in the study to determine if this was a safe and appropriate thing to do. It would seem vital to ensure that the patients that the tool recommends for non-conveyance were not discharged in error.

    In attempting to be easily applied by all front-line staff, the tools also fail to account for the grade of clinician making the clinical decision. As already stated, improved training allows paramedics to avoid ED admissions more often[3-5], so it would be important to establish if this triage tool performs equally well for each grade of clinician. One would presume that the sensitivity and specificity of a clinician making the same decision without the tool should increase as their clinical grade becomes more senior, but this increased experience and knowledge risks being over-ridden by the use of a rigid protocol unless some flexibility is built in. Additionally, the tool makes use of the Pre-Hospital Early Warning Score (PHEWS) to filter out patients at risk. As with similar track-and-trigger protocols, this fails to consider patients with baseline "abnormal" physiology, nor does it allow for normal paediatric physiology, despite Paramedic Pathfinder being recommended for use in anyone over the age of five. Strictly applying PHEWS further reduces the clinician's autonomy in deciding what they feel is best for their patient.

    Although we welcome the efforts of Newton et al in developing a tool to assist paramedics in making such clinical decisions, we are concerned that the Paramedic Pathfinder tool risks reducing highly trained and experienced pre-hospital professionals to a flowchart, with no scope to take account of a patient's holistic needs or wishes. When providing increased training and skills to front-line staff has been shown to just as effectively reduce ED attendance safely, this paper provides no compelling evidence that increased reliance on rigid and inflexible protocols instead will achieve a better outcome for patients. We feel that Paramedic Pathfinder will become a useful tool in providing clinicians with a safety net when making decisions regarding use of alternative referral pathways, especially when used by less qualified pre-hospital practitioners, but this can only be achieved in concert with improved training and increased clinical autonomy for pre-hospital practitioners, and the tool needs to be validated in a national setting before widespread implementation can be supported.

    James Goulding, Paramedic, Yorkshire Ambulance Service NHS Trust.
    Dr Nick Plummer, Academic foundation doctor, Lancashire Teaching Hospitals NHS Foundation Trust.

    [1] Newton, M., Tunn, E., Moses, I., et al. 2013. Clinical navigation for beginners: the clinical utility and safety of the Paramedic Pathfinder. Emerg Med J Published Online First: 7 October 2013.
    [2] Snooks, H., Foster, T., et al. 2004. Results of an evaluation of the effectiveness of triage and direct transportation to minor injuries units by ambulance crews. Emerg Med J , 21(1), 105-111
    [3] Mason, S., Knowles, E., et al. 2007. Effectiveness of paramedic practitioners in attending 999 calls from elderly people in the community: cluster randomised controlled trial. Brit Med J, 335(7626), 919.
    [4] Gray, J. T. and Walker, A. (2008). Avoiding admissions from the ambulance service: a review of elderly patients with falls and patients with breathing difficulties seen by emergency care practitioners in South Yorkshire. Emerg Med J , 25(3), 168-171.
    [5] Clesham K, Mason S, Gray J et al. 2008. Can emergency medical service staff predict the disposition of patients they are transporting? Emerg Med J 25(10): 691-4
    [6] AACE (2014) Measuring Patient Outcomes: Clinical Quality Indicators [online at: http://aace.org.uk/national-performance/ accessed 19/06/2014]

    Conflict of Interest:

    None declared

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  4. Access to a helipad and the impact to the hospital

    We read with interest the article written by Freshwater et. al. (1) 'Extending access to specialist services: the impact of an onsite helipad and analysis of the first 100 flights' and were very impressed with the findings and at the outset we would like to congratulate the authors on this innovative analysis. This paper demonstrates the great impact retrievals and transfers can have on the referred hospital, however we provide some constructive criticism on the article below.

    Although this article is a first in investigating the success of a new helipad at the University Hospital Southampton (UHS), we feel that the authors have overlooked more updated and recent data on the number of missions flown annually in the UK. The Association of Air Ambulances' website, under the document '2013 Framework for A High Performing Air Ambulance(2)', states that 19 charity air ambulances flew approximately 25500 missions in 2012. This is considerably more than the 19,000 stated within the article. Following this, additional numbers of charities have been established, thus we feel that the total figures until the time this article was published will be far greater. This updated information would have only strengthened the findings of this study.

    On a similar note, regarding 'blue-light' times vs normal speed drive times, a more recent article by McKeekin et. al. (3) states that whilst the software used is appropriate to estimate 'blue-light' times from normal speed drive times (as stated by the authors in the article), more importantly there needs to be adjustments made in the software to account for population density, traffic and other factors involved. This again is more recent evidence than that quoted by the authors in this paper (4) (5).

    Due to the nature of this type of study, the results are quite subjective because it is human decision whether to send the patient via air to the hospital. That human is not always the same and changes per shift, and therefore there may be some times where patients were sent to UHS or alternative sites when others would not have made that decision. This can alter the results, and therefore for future studies, it is important to address this issue to ensure results are as accurate as possible. We appreciate that the sample size was small because the service was new, however we would suggest that in future, the data would be more accurate if a larger sample size is analysed over a greater period, by comparing with other trauma centres which have helipads. Also it is important to compare results internationally to better understand the findings in a national and international context. Finally, a discussion into the implications on the staff, resources and wards of the hospital since the introduction of the helipad would be equally important.

    Once again, we commend the authors on a brilliant piece of work, and look forward to reading further articles exploring into this topic further.

    1. Freshwater ES, Dickinson P, Crouch R, Deakin CD, Eynon CA. Extending access to specialist services: the impact of an onsite helipad and analysis of the first 100 flights. Emergency Medicine Journal. 2014;31:121-5.

    2. Association of Air Ambulances. Framework for A High Performing Air Ambulance. 2013:9. Available from: http://www.associationofairambulances.co.uk/resources/events/AOAA- Framework%202013-OCT13-%20Final%20Document.pdf [Accessed on 13.04.2014]

    3. McMeekin P, Gray J, Ford GA, Duckett J, Price CI. A comparison of actual versus predicted emergency ambulance journey times using generic Geographic Information System software. 2013;0:1-5.

    4. Lerner EB, Billittier AS. Delay in ED arrival resulting from a remote helipad at a trauma center. Air Med J. 2000;19(4):134-6.

    5. Hunt RC, Brown LH, Cabinum ES, Whitley TW, Prasad NH, Owens CF, Jr., et al. Is ambulance transport time with lights and siren faster than that without? Ann Emerg Med. 1995;25(4):507-11.

    Conflict of Interest:

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  5. Don't ignore the ASA grade.

    We welcome our Edinburgh colleagues' further contribution1 to the emergency medicine literature regarding procedural sedation for relocating hip prostheses. Their work raises a number of points worthy of debate.

    The number of patients in their study is unlikely to accurately determine a relationship between ASA grade and complication rates. This is particularly so for (meaningful) sentinel adverse events and outcomes since we have demonstrated that these are rare2, occurring in only about 1% of patients sedated with propofol. The notion that ASA grade has no influence on complication rate defies logic. Since the Edinburgh paper was submitted, a consensus working party adverse event reporting tool has been published3 allowing meaningful comparison of data between studies. Dawson and colleagues' work would be more helpful if re-analysed using these parameters, rather than (undefined) apnoea (as opposed to apnoea >60s) and desaturation <90% at any time (as opposed to <75% at any time or <90% for >60s).

    The successful relocation rate of 78% is poor and likely reflects the limited use of propofol in their study - 87 of 204 patients (30%). Our work has previously demonstrated success rates of about 95% with this agent (their references five and six). It is our opinion that a deep level of sedation is required to enable relocation of a joint on which such large muscle groups act. Propofol reliably allows this, as indeed does larger doses of midazolam; it is the short duration of action of the former that is its key advantage. We applaud their cautious approach to the sedation of this elderly patient group. An updated version of our protocol which they quote is available (www.enlightenme.org/); notable features include the use of nasal capnography and an emphasis on a smaller (0.5mg/kg) bolus and top- up for this age group.

    Refs

    1. Dawson N, Dewar A, Gray A, et al. Association between ASA grade and complication rate in patients receiving procedural sedation for relocation of dislocated hip prostheses in a UK emergency department. Emerg Med J 2014;31:207-209 2. Newstead B, Bradburn S, Appelboam A, et al. Propofol for adult procedural sedation in a UK emergency department: Safety profile in 1008 cases. BJA 2013;111(4):651-5 3. Mason K, Green S, Placevoli, et al. Adverse event reporting tool to standardize the reporting and tracking of adverse events during procedural sedation: a consensus document from the World SIVA International Sedations Task Force. BJA 2012;108(1):13-20

    Conflict of Interest:

    We have published in this clinical arena in this and another journal.

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  6. Re:AP pelvis and frog lateral for a limping child

    Many thanks for your letter. With the benefit of hindsight, the radiographs do show signs suggestive of SUFE. However, the original radiographs were reviewed by a senior A&E doctor in a peripheral hospital, and reported by a consultant radiologist as possible Perthes. This was also the working diagnosis of a consultant paediatric orthopaedic surgeon who reviewed the chid in clinic. SUFE was not suspected possibly because of the child's very young age. An MRI was requested due to the abnormal appearance of the femoral epiphysis, but the appointment was missed. Had a frog lateral radiograph been arranged, the diagnosis would have been more obvious.

    Whilst we share your concern on radiation exposure, missing the diagnosis as illustrated in this case is a bigger worry. These radiographs are routinely reviewed by junior frontline doctors that are not necessarily experienced in assessing the paediatric hip. We would normally use MRI to further investigate cases of hip pain, but in this particular case, the purpose of a CT was to delineate the bony architecture with 3D reformats to plan possible surgical intervention for the missed slip.

    A frog lateral view only may well be sufficient to diagnose most hip pathology; however, we would be cautious in recommending this without prospective evidence across a large number of patients, with radiographs assessed by frontline doctors.

    Conflict of Interest:

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  7. Mobile apps - are we culturally out of signal?

    As an avid user of mobile apps currently working in Emergency Medicine, I enjoyed reading this article (and have since downloaded a couple of apps!). I have found mobile apps are a useful adjunct to my work in the Emergency Department, most commonly for checking drug doses using the British National Formulary app or using a Snellen Chart app in a departmental bay.

    I do think, however, if mobile apps are to be integrated into clinical practice that there needs to be a regulatory and cultural revolution. Authoritative signs dictating 'do not use your mobile phone' litter many hospitals and, in my opinion, have contributed to patients challenging my use of them. Additionally, there is the cultural perception that if you are 'checking your phone' you are probably on a social media site when in actual fact you could well be checking the hospital's antibiotic guidelines for a septic patient.

    From a regulatory point of view, I think at the moment we need to be cautious when using these apps. Very few of these have approval of regulatory bodies such as the Medicines and Healthcare products Regulatory Agency (MHRA) in the case of the UK. If we are using these apps to diagnose and manage patients, we need to view them as much of a medical device as a pulse oximeter.

    Emergency Medicine is incredibly varied and, for that reason, is probably the most ideal specialty to embrace mobile apps. I cannot see a future for the specialty without mobile apps but I think we need to be careful and open about using them.

    Conflict of Interest:

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  8. Is videolaryngoscope superior to direct laryngoscopes for tracheal intubation during chest compressions?

    In a manikin study simulating cardiopulmonary resuscitation, Tandon et al.1 showed that intubation time was shorter for GlideScope?? videolaryngoscope than direct laryngoscope. This result agrees with the findings of Shin et al2 and Xanthos et al3 in manikin studies simulating cardiopulmonary resuscitation. However, in other similar manikin studies, GlideScope?? videolaryngoscope was not superior to direct laryngoscope with regard to intubation time.4,5 In all these manikin studies,1-5 the authors suggest that further clinical trials are required to evaluate the effectiveness of the studied devices in patients. One of important reasons for this statement is that the manikin cannot precisely reproduce the intubation conditions of real patients. Also, the airway scenarios simulated in manikin studies cannot represent real clinical situations. Despite numerous manikin comparing GlideScope?? videolaryngoscope and direct laryngoscope for tracheal intubation during cardiopulmonary resuscitation, it is really unclear what these contradictory results can tell us for clinical decision-marking. Rai and Popat6 have pointed out that manikin studies often reveal results that are impossible to interpret or even contradictory to subsequent human studies. An example of this is a recent randomized controlled clinical trial by Arima et al7 comparing the Airwayscope and direct laryngoscope for tracheal intubation in prehospital patients primarily with cardiac arrest. In manikin studies simulating cardiopulmonary resuscitation, the Airwayscope has been demonstrated to be superior to direct laryngoscope for tracheal intubation.8,9 However, when tracheal intubation was performed by experienced emergency physicians in the prehospital cardiopulmonary resuscitation patients, the Airwayscope did not show superior efficacy to direct laryngoscope in relation to intubation time, success rate, and difficulty of intubation. Moreover, initial intubation with the Airwayscope failed in 20 cases but was followed by successful intubation with the direct laryngoscope. A major cause of failed first intubation attempt with the Airwayscope was oral vomitus or secretion contamination, which was found in 45 of the total 109 cases (41%) in this clinical study.7 Simple or even sophisticated manikins cannot model vomitus or secretions regurgitated from the esophagus or trachea due to increased intra-thoracic pressure from chest compressions.8 Here, we would like to echo Behringer and Kristensen10 that manikin studies may be warranted in the evaluation of new intubation equipment as a means to teach a technique, maintain safety and oversee conduct of an ensuing clinical study, but they are of negligible value as sole predictors of any given airway device's value in the clinical realm. Thus, to obtain robust evidence regarding exact role of videolaryngoscopes in airway management of cardiopulmonary resuscitation patients, randomized controlled trials comparing each videolaryngoscope against an established alternative (for example, direct laryngoscope) in actual clinical settings are still needed. Shi Yu Wang, Fu Shan Xue, Rui Ping Li Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China. Correspondence to Fu Shan Xue, Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 33 Ba-Da-Chu Road, Shi-Jing-Shan District, Beijing 100144,China. Email: xuefushan@aliyun.com; fushan.xue@gmail.com References 1. Tandon N, McCarthy M, Forehand B, et al. Comparison of intubation modalities in a simulated cardiac arrest with uninterrupted chest compressions. Emerg Med J 2013; In Press. doi:10.1136/emermed2013-202783. 2. Shin DH, Choi PC, Han SK. Tracheal intubation during chest compressions using Pentax-AWS?, GlideScope?, and Macintosh laryngoscope: a randomized crossover trial using a mannequin. Can J Anesth 2011; 58:733-9. 3. Xanthos T, Stroumpoulis K, Bassiakou E, et al. Glidescope? videolaryngoscope improves intubation success rate in cardiac arrest scenarios without chest compressions interruption: a randomized cross-over manikin study. Resuscitation 2011; 82:464-7. 4. Kim YM, Kang HG, Kim JH, et al. Direct versus video laryngoscopic intubation by novice prehospital intubators with and without chest compressions: A pilot manikin study. Prehosp Emerg Care 2011; 15:98-103. 5. Kim YM, Kim JH, Kang HG, et al. Tracheal intubation using Macintosh and 2 video laryngoscopes with and without chest compressions. Am J Emerg Med 2011; 29:682-6. 6. Rai MR, Popat MT. Evaluation of airway equipment: man or manikin? Anaesthesia 2011; 66:1-3. 7. Arima T, Nagata O, Miura T, et al. Comparative analysis of airway scope and Macintosh laryngoscope for intubation primarily for cardiac arrest in prehospital setting. Am J Emerg Med 2014; 32:40-3. 8. Komasawa N, Ueki R, Itani M, et al. Validation of the Pentax-AWS Airwayscope utility as an intubation device during cardiopulmonary resuscitation on the ground. J Anesth 2010; 24:582-6. 9. Komasawa N, Ueki R, Kohama H, et al. Comparison of Pentax-AWS Airwayscope video laryngoscope, Airtraq optic laryngoscope, and Macintosh laryngoscope during cardiopulmonary resuscitation under cervical stabilization: a manikin study. J Anesth 2011; 25:898-903. 10. Behringer EC, Kristensen MS. Evidence for benefit vs novelty in new intubation equipment. Anaesthesia 2011; 66 Suppl 2:57-64.

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  9. AP pelvis and frog lateral for a limping child

    We read the article "AP pelvis and frog lateral for a limping child"(1) with some concern for radiation safety. The AP pelvis radiograph at presentation does not show merely slight irregularity of the articular surface as stated in the article, but a reduction of height of 50% of the left femoral capital epiphysis, increased density projected across the growth plate, loss of clarity and contour of the growth plate and lateralisation of the left hip - all classical signs of slipped epiphysis. In our hospital we performed a study by which we reviewed all cases where an AP and lateral pelvis had been performed over a period of 2 years (2). This showed that the AP view very rarely demonstrated abnormality not seen on the lateral view, whereas the converse is not true. Our protocol since 2008 is frog lateral only for painful hip except where there is a history of trauma. To our knowledge there have been no missed diagnoses as a result of this policy. If any further investigation is required we prefer MRI to CT, which delivers high dose to the gonads in hip examinations.

    1.Sultan J, Ali F. Emerg Med J Published online first. 13th January 2014 doi 10.1136/ememed-2013 203366

    2. Is a single radiograph adequate screening for possible slipped upper femoral epiphysis? Gummow A, McGurk SF, WilkinsonAG. Pediatr Radiol (2008) 38 (Suppl 3) S537

    Conflict of Interest:

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  10. COMMENTS ON: "BET 3: Evaluation of intra-aortic balloon support in cardiogenic shock"

    COMMENTS ON: "BET 3: Evaluation of intra-aortic balloon support in cardiogenic shock"

    Maria Cristina Acconcia(a), MD, Flavia Chiarotti(b), DStat, Francesco Romeo(c), MD, Quintilio Caretta(d*), MD.

    (a)Department of Cardiovascular Disease, University of Rome - La Sapienza, Rome, Italy (b)Department of Cell Biology and Neuroscience, Italian National Institute of Health, Rome, Italy (c)Department of Cardiovascular Disease, University of Rome - Tor Vergata, Rome, Italy (d) Department of Clinical and Experimental Medicine, University of Florence, Florence, Italy

    *Corresponding author at: Quintilio Caretta, MD, Clinical and Experimental Medicine, University of Florence, Largo Brambilla, 3 - 50134 Florence, Italy. Tel: 0039-3487809379; Fax: 0039-06-20904008;E-mail: qcaretta@unifi.it.

    In the meta-analysis "The outcome of intra-aortic balloon pump support in acute myocardial infarction complicated by cardiogenic shock according to the type of revascularization" by Romeo et al (2013), we assessed the impact of intra-aortic balloon pump (IABP) on in-hospital mortality, safety end points (stroke, severe bleeding) and long-term survival, using risk ratio (RR) and risk difference (RD) estimates(1). We found that IABP support did not significantly affected the risk of death in patients who did not undergo reperfusion, while it reduced significantly in the Thrombolysis (TT) subgroup and significantly increased in the percutaneous coronary intervention (PCI) subgroup the in-hospital mortality.

    Humphrey et al (2013) recently performed a short-cut review to establish whether IABP improves mortality in cardiogenic shock after acute myocardial infarction (2) including our meta-analysis(1) . In Table 3 they stated that the use of the observational studies and the different mortality rates among the three subgroups (83.9% for the no reperfusion subgroup, 66.9% for the TT subgroup, and 38.4% for the PCI subgroup), suggested a weakness of the study. They concluded that "the role of IABP support in patients with cardiogenic shock from myocardial infarction remains unclear, without evidence of clear confirmed benefit compared to conventional therapy, especially when PCI is available". With respect to these remarks we would like to make some comments. First, the statement on the observational studies is formally correct, but in the scientific literature the evidence of IABP support in cardiogenic shock is mainly based on registry data, due to feasibility; indeed, in our meta-analysis the inhospital mortality was analyzed on 14186 patients from 16 studies, 13 observational, including 13526 patients, and 3 randomised controlled trials, contributing with 22, 40, and 598 patients, respectively. Furthermore in our meta-analysis we adopted the more conservative random effect model to take into account heterogeneity among studies. In adjunct Benson and Hartz (2000) performed meta-analyses of randomised clinical trials and observational studies and found that treatment effect estimates from observational studies reported after 1984 were similar to those obtained in randomised controlled trials(3). Also, in their meta-analyses based on randomised clinical trials and observational studies on identical clinical topics, Concato et al (2000) found that the average results of well-designed observational studies (with either a cohort or a case-control design) were markedly similar to those of the randomised controlled trials(4). Finally, an integrated approach is advisable because "Discarding observational evidence when randomised trials are available is missing an opportunity. Conversely, abandoning plans for randomised trials in favour of quick and dirty observational designs is poor science"(5). Second, we think that the authors did not take into appropriate account the role of reperfusion strategies as confounding factor in the meta- analysis. Indeed, from a clinical point of view it is quite different to support patients affected by cardiogenic shock with IABP alone, or with IABP in combination with TT or PCI. This is clearly demonstrated in our meta-analysis by the fact that the three groups of patients who did not receive IABP support (control groups) had significantly different in- hospital mortality rates due to the clinical treatment (83.9%, 66.9%, 38.4%, for no reperfusion, TT and PCI, respectively) (see Figure 4 in Romeo et al, 2013)(1). Thus the actual impact of IABP support could be assessed only if the subgroups were stratified according to clinical treatment. And this must not be interpreted as a gap, but as correct application of the statistical method. Finally, we performed a trial sequential analysis (TSA) using TSA program (The Copenhagen Trial Unit, Center for Clinical Intervention Research CTU, Denmark; version 0.9 beta; available at www.ctu.dk/tsa)(6,7) to settle any further doubt. TSA provides the required information size, a threshold for a statistical significant treatment effect and a threshold for futility. We calculated the relative risk reduction (RRR) both for RR and RD, using the event proportion observed in the control group (i.e. the basal risk) and the actual difference in risks between the experimental and control group observed in our meta-analysis. TSA performed on TT and on PCI subgroups demonstrated that the sample sizes were adequate to verify the hypotheses. The required number of participants was reached in both subgroups of patients (TT: RR, n=1646 and RD, n=1287, RRR=26.6%; PCI: RR, n=2671 and RD, n=2523, RRR=-18.2%). The monitoring boundaries constructed to detect significance were crossed by the z-curves. Thus, our meta- analysis can be considered as conclusive in contrast with the final statement by Humphrey et al (2013)(2).

    References 1. Romeo F, Acconcia MC, Sergi D, et al. The outcome of intra-aortic balloon pump support in acute myocardial infarction complicated by cardiogenic shock according to the type of revascularization: A comprehensive meta-analysis. Am Heart J 2013:165:679-92. 2. BET 3: Evaluation of intra-aortic balloon support in cardiogenic shock. Emerg Med J 2013;30:1063-4. 3. Benson K, Hartz AJ. A comparison of observational studies and randomized, controlled trials. N Engl J Med 2000;342:1878-86. 4. Concato J, Shah N, Horwitz RI. Randomized, controlled trials, observational studies, and the hierarchy of research designs. N Engl J Med 2000;342:1887-92. 5. Ioannidis JPA, Haidich A-B, Lau J. Any casualties in the clash of randomised and observational evidence? No--recent comparisons have studied selected questions, but we do need more data. 2001;322:879-80. 6. Thorlund K, Engstr?m J, Wetterslev J, et al. User manual for trial sequential analysis (TSA). Copenhagen Trial Unit, Centre for Clinical Intervention Research, Copenhagen, Denmark. 2011. p. 1-115. Available from www.ctu.dk/tsa 7. Wetterslev J, Thorlund K, Brok J, et al. Estimating required information size by quantifying diversity in a random-effects meta- analysis. BMC Medical Research Methodology 2009;9:86.

    Conflict of Interest:

    None declared

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