ORIGINAL ARTICLE Comparing performance and impact of first responders on outcome in prehospital emergency medicine in Switzerland

NATALIE URWYLER 1,2 , L ORENZ THEILER 1,3 , J OHANN SCHÖNHOFER 1, B RUNO KÄMPFEN 4, CHRISTOPHER STAVE 5, R OBERT GREIF 1 1University Department of Anesthesiology and Pain Therapy, University of Bern, Bern, Switzerland. 2Department of Pathology, Stanford University School of Medicine, Stanford, California, USA. 3Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, Florida, USA. 4Department of Anesthesiology, Spitalzentrum Oberwallis, Visp, Switzerland. 5Lane Medical Library & Knowledge Management Center, Stanford University School of Medicine, Stanford, California, USA.

CORRESPONDENCE : Background: Contradictory results are reported in the medical literature on effectiveness Natalie Urwyler of first responders in prehospital emergency medicine. In this study we evaluated Universitary Hospital of Bern responders performance and impact on outcome. 3010 Bern, Switzerland Methods: In a retrospective cohort study we evaluated the accuracy of diagnoses by E-mail: emergency physicians, paramedics, and general practitioners. We compared the natalie –[email protected] diagnosis made in the prehospital emergency situation to the diagnosis at discharge from the hospital. Primary outcome was the impact of accuracy of diagnosis on RECEIVED : 28-6-2012 mortality. Secondary outcomes were, 1) time on scene, 2) duration of hospitalization. The influence of clinical experience and postgraduate training on accuracy of diagnoses ACCEPTED : was of particular interest. 16-8-2012 Results: We evaluated 1241 diagnoses. admitted with a wrong or missing diagnosis showed an increased mortality risk ( P = 0.04, OR 1.9; CI 1.04-3.34). The time CONFLICT OF INTEREST : spent on scene and the duration of his/her hospital stay was shorter if the diagnosis was None correct. Emergency physicians, paramedics and general practitioners made diagnoses with comparable accuracy ( P = 0.139) but emergency physicians showed a significant ACKNOWLEDGEMENTS : increase in accuracy correlated to their years of clinical experience ( P < 0.001). After We thank Enrique Cuellar, PhD, postgraduate year six they reached a level of diagnostic accuracy > 90%. This effect for English language editing and important contributions to could not be shown for paramedics or general practitioners. the manuscript. We would like Conclusion: A correct diagnosis in prehospital emergency medicine reduces mortality to thank Katharina Seidl, and length of hospital stay. Trained emergency physicians make diagnoses with a high University Department of degree of accuracy. Therefore, they should be increasingly integrated into prehospital Anesthesiology and Pain emergency medicine, particularly for more severe cases. [Emergencias 2012;24:426-432] Therapy, University Hospital of Bern, Switzerland, who helped Keywords: Accuracy of Diagnosis. Prehospital Emergency Medicine. Emergency Medical collecting data. We thank Dr. Services. Emergency Physician. Paramedics. Postgraduate Training. Christian Seidl, University Department of Anesthesiology and Pain Therapy, University Hospital of Bern, Switzerland for participation on the board of certified emergency physicians. We would like to thank the Sanität Oberwallis, Visp, Switzerland for collaboration on this investigation.

426 Emergencias 2012; 24: 426-432 COMPARING PERFORMANCE AND IMPACT OF FIRST RESPONDERS ON OUTCOME IN PREHOSPITAL EMERGENCY MEDICINE IN SWITZERLAND

Introduction Nevertheless, general practitioners are still fre - quently involved in prehospital emergency medi - Despite a decades-long evolution in the sophis - cine in Switzerland. tication of emergency medical services (EMS), there In this study we evaluated the performance of is no consensus on the effectiveness of prehospital first responders within the newly reorganized first responders and their relative impact on Swiss EMS system by evaluating the accuracy of outcome. Although it is generally acknowledged prehospital diagnosis and its impact on patient that safe and timely transport is needed for most outcome. A correct diagnosis leads to the initia - individuals experiencing an acute medical problem, tion of accurate emergency treatment and gives a experts have questioned the composition and value broader measure of the effect of first responder of EMS systems 1-4 . A landmark Canadian study performance compared to evaluation of specific showed equal or better outcome when emergency skills (e.g. airway management). patients received basic life support provided by emergency medical technicians compared to ad - vanced life support provided by emergency physi - Methods cians or paramedics in a prehospital emergency setting 5. On the other hand, a British study showed We evaluated the effectiveness of prehospital that appropriately trained emergency physicians emergency medicine on patient outcome by rank - bring hospital-level interventions to critically injured ing the accuracy of the prehospital diagnosis in and unwell patients in the prehospital emergency two categories: The first category was “correct di - setting and thereby provide a level of care beyond agnosis”, second “wrong” and “missing diagno - that provided by paramedics 6. Other studies sis” were analyzed as one category. The primary showed that first responders with superior training outcome was the impact of accuracy of diagnosis in emergency medicine had higher success rates in on mortality, defined as death occurring within 30 prehospital airway management compared to less days after admission to the hospital. Secondary trained first responders 7-9 . Several studies compar - outcomes were: 1) Time on scene in minutes ing ground and helicopter transport showed a de - spent with the patient in the prehospital emer - crease in mortality due to the speed of the helicop - gency situation, defined as time of arrival on ter and the higher specialized training in scene until departure from the scene of incidence; emergency medicine of the helicopter rescue 2) Duration of hospitalization in days, and 3) The teams 10-14 . The condition of an emergency patient number of laboratory tests blood draws ordered can worsen rapidly in a life-threatening situation. In upon admission in the a prehospital environment, quick decision-making (ED) within the first 24 hours. and rapid initiation of treatment are critical and of - Patient outcome parameters were compared ten lifesaving 15,16 . Making the correct diagnosis, between patients with a “correct” diagnosis and based on proper patient assessment, is crucial to patients with a “wrong or missing diagnosis”. Pa - initiating an appropriate emergency treatment. In tients rescued by a land-based EMS show a wide addition, correct assessment of the severity of a variety in severity of different diseases and injuries. case is a prerequisite for starting appropriate triag - We used the NACA Score to distinguish between ing and specific assignment to the rapid response patients with a potentially life threatening injury team of the receiving hospital 17,18 . or disease (NACA Ն 4) and patients without a life Over the last two decades organizational struc - threatening injury or disease (NACA < 4; Table tures of EMS in Switzerland have changed. A na - 1) 20,21 . We also used the NACA Score system to tion-wide emergency number was introduced comparable to 911 in the USA. An additional Table 1. The National Advisory Committee on Aeronautics change was to integrate emergency physicians in - (NACA) Score to the EMS systems starting in helicopter EMS. Prior to these changes, general practitioners were NACA Patient status Necessary Intervention called to see prehospital emergency patients (e.g., I Slight injury or illness No medical intervention II Moderately heavy injury or illness Ambulatory medical treatment patients involved in car accidents or patients with III Heavy, but not life threatening Stationary medical treatment medical problems at home). Today various land- injury or illness based EMS units have systems where an emer - IV Heavy injury or illness, life threat cannot be excluded gency physician is added to the team of para - V Acute mortal danger Emergency medical measures medics if a life-threatening medical condition is VI Acute cardiac or respiratory arrest Emergency medical measures suspected, similar to EMS systems in Germany 19 . VII Death Emergency resuscitation

Emergencias 2012; 24: 426-432 427 N. Urwyler et al.

evaluate the assessment of severity of cases by the to the NACA Score given by the board of certified first responders in the prehospital emergency situ - emergency physicians based on the final diagnosis ation. in the discharge letter. We conducted a retrospective cohort study of A standard rescue team consists of one para - patients rescued by a land-based EMS system medic and one driver. In cases where the dis - (Sanität Oberwallis, Visp, Switzerland). The co - patcher suspects a life-threatening event horts were patients admitted to a Level lll trauma (NACA Ն 4), an emergency physician is brought center (Spitalzentrum Oberwallis, Visp, Switzer - to the scene. In addition, paramedics have the land) in the alpine region of Switzerland with a opportunity to call for an emergency physician if “correct diagnosis” versus patients admitted with they feel that they need more on-scene support. a “wrong” or “missing diagnosis”. The nearest In cases already involving a general practitioner, Level I is two hours away by an additional emergency physician is rarely sent ground transportation or 45 minutes by rescue to the scene. The effect of clinical experience, helicopter over a mountain chain of > 4000 m el - training and education on accuracy of diagnosis evation and frequently challenging weather condi - was of particular interest. We correlated the accu - tions. Therefore, the common practice is to trans - racy of diagnosis to years of clinical experience port patients to a Level III trauma center for initial and postgraduate training of the three groups of treatment and stabilization. If necessary, patients first responders (emergency physicians, para - are later transported to a Level I trauma center. medics, general practitioners). The classification of the hospital was done accord - Emergency Physicians: “Emergency Physician ing to the American College of Surgeons Trauma SGNOR” (Swiss Society of Emergency and Rescue Program 22 . The level lll trauma center evaluated in Medicine) is a certification which can be achieved our study provides primary care, resuscitation, in combination with one of the main specialties of emergency operation, stabilization, and transfer acute medicine (e.g. anesthesiology, surgery or in - for definitive care 24 hours, seven days a week. ternal medicine). After graduation from a Swiss or Compared to a level l trauma center it does not Swiss-accredited university medical school (6 provide neuro- or cardiac surgery. years), a minimum of three years of postgraduate Participants included all patients rescued by training are required to become a certified emer - the EMS in one year (2008) and brought to the gency physician. One year of residency in internal level lll trauma center. Inter-hospital transports medicine, one in anesthesiology, and a three were excluded because diagnoses were made by month full-time rotation in an Emergency Depart - the physicians of the transferring hospital. ment and an (ICU) are A board of three SGNOR certified emergency mandatory. The third year can be in another spe - physicians reviewed all cases retrospectively. De - cialty of acute medicine (e.g. surgery, pediatrics, termination of accuracy of diagnosis and NACA orthopedics) 23 . In this study, emergency physicians Score was accomplished by comparing the text in were both “in training” (post graduate year, PGY the electronic case reporting system of the EMS 3 – 6) and “certified” (up to 25 years of clinical prehospital diagnosis to the diagnosis in the dis - experience). charge letter, also in text form. The diagnosis at Paramedics: Paramedic certification in Switzer - discharge was considered as accurate. The prehos - land requires three years of full-time training in a pital diagnosis was rated as “correct” if the main College of Higher Vocational Education. The train - diagnosis responsible for the medical emergency ing consists of about 2000 hours of theoretical situation was correct. The prehospital diagnosis learning and about 3400 hours of practical learn - was rated as “wrong” if the main diagnosis was ing in an EMS. Internships of two to three weeks wrong. The diagnosis was rated as “missing diag - have to be undertaken in an ED, ICU, or anesthe - nosis” if the first responders only described symp - siology. All paramedics in this study were “certi - toms in their report but failed to provide a diag - fied”, their clinical experience was between one nosis. To guarantee a majority decision in every and eighteen years. case, the number of certified emergency physician General Practitioners: General practitioners at - of the board was uneven. Members of the board tend a Swiss or Swiss-accredited university med - were blinded to the composition of the rescue ical school (6 years). Following medical school, team and patient data was anonymized before re - graduates embark on a mandatory five-year post - view and analysis. graduate training program in general internal First responders gave a NACA Score for each medicine. At least two years of in-hospital train - case. Its accuracy was evaluated by comparing it ing are followed by one year of outpatient train -

428 Emergencias 2012; 24: 426-432 COMPARING PERFORMANCE AND IMPACT OF FIRST RESPONDERS ON OUTCOME IN PREHOSPITAL EMERGENCY MEDICINE IN SWITZERLAND

1326 patients rescued by EMS and admitted to level III trauma center

3 inter-hospital transports

1323 patients

Figure 2. Information on admitting medical disciplines and se - verity of cases at admission separated by a dotted line. Correc - ted NACA Score given by the board of certified emergency 82 patients data physicians was used, no patient was NACA Vll on admission. not available

Kruskal-Wallis test was used. Chi-square test or Fisher’s exact test analyzed frequency data. A sig - 1241 patients evaluated by the board nificance level of p < 0.05 was considered as sig - of certified emergency physicians nificant. Effect sizes for frequency data are given as odds ratio (OR) with 95% confidence intervals (CI). Statistical analysis was performed using SPSS Figure 1. Study Flow Chart 18.0 (IBM Corporation, New York, USA). ing in cooperation with private practice centers. The last two years provide electives in other med - Results ical specialties (e.g. surgery, gynecology and ob - stetrics, pediatrics). A board exam must be A total of 1326 patients were rescued by the passed. Additionally a four-day course in basic land-based EMS system and brought to the level emergency medicine has to be completed during lll trauma center. Three interhospital transports residency 24 . All general practitioners in this study were excluded. Of the remaining 1323 patients, were board certified and practicing in their own data was not available for 82 cases. A total of offices. Their clinical experience was between 11 1241 cases with complete data sets underwent and 36 years. evaluation for accuracy of diagnosis and retro - Prehospital data was collected from the elec - spective assessment of NACA Score by the board tronic case reporting system of the EMS. The di - of certified emergency physicians (Figure 1). Pa - agnosis at discharge was obtained from the dis - tients had a median age of 62 years (IQR 39 -78), charge letter in the electronic patient data (range < 1 year to 99 years) with a peak between management system of the admitting level III 60 to 90 years 120 (10%) were children, 597 trauma center. Data was entered into a dedicated (48%) were female patients and 644 (52%) male. database for further analysis. The study was ap - Admitting disciplines and distribution of severity proved by the relevant Swiss Institutional Review of cases are shown in Figure 2. Board (CCVEM 030/09, Commission Cantonale Patients with a potentially life threatening in - Valaisanne d’éthique Médical, Sion, Switzerland). jury or disease (NACA Ն 4) admitted with a Data were checked for normality by visual wrong or missing diagnosis had an increased evaluation of the shape of the normality distribu - mortality risk (p = 0.04, OR 1.9; CI 1.04 – 3.34). tion curve (QQ-plot). All data were represented For patients without a life-threatening injury or using graphical data analysis and subsequently disease (NACA < 4) there was no statistical differ - subjected to the standard statistical tests, as de - ence in mortality (p = 0.13). The time needed to scribed below. Data between the two groups make a correct diagnosis did not increase the were compared with Student’s t-test or ANOVA time spent with the patient on scene in the pre - for multiple groups if normality could be as - hospital emergency situation. On the contrary, sumed. Otherwise, Mann-Whitney u-test or time on scene with the patient was shorter for pa -

Emergencias 2012; 24: 426-432 429 N. Urwyler et al.

Table 2. Impact of accuracy of diagnosis on patient outcome for patients with a possibly life threatening injury or disease (NACA Ն 4) and for patients without (NACA < 4) NACA Ն 4 NACA < 4 Diagnoses Wrong or P Diagnoses Wrong or P n (%) missing n (%) missing n (%) n (%) Death n (%) 20 32 0.035 040.059 Time on scene min (SD) 19.8 (11.6) 22.6 (12.2) 0.005 16.9 (11.8) 18.1 (10.1) 0.169 Blood draws (SD) 1.84 (1.65) 1.78 (1.35) 0.65 0.81 (0.9) 1.23 (1.16) < 0.001 Hospitalization days (SD) 6.3 (7.5) 8.2 (7.3) 0.003 3.4 (5.0) 5.4 (6.8) < 0.001 Time on scene = time of arrival on scene until departure from the scene of incidence in minutes spent with the patient in the prehospital emergency situation, Lab count blood draws = number of blood draws laboratory values ordered within the first 24 hours after admission of the patient, hospitalization days = duration of hospital stay in days. tients NACA Ն 4 with a correct diagnosis. For pa - (p = 0.022). The same effect of increased accuracy tients NACA < 4 there was no difference in time in more severe cases could not be shown for para - on scene spent with the patient in the prehospital medics (NACA < 4 = correct in 47%, NACA Ն 4 emergency situation. Significantly fewer laborato - correct in 50%, p = 0.554) or for general practi - ry tests blood draws were ordered in the first 24 tioners (NACA < 4 = correct in 46%, NACA Ն 4 hours in patients with NACA < 4 who were admit - correct 49% p = 0.666). Both paramedics and ted with a correct diagnosis. In patients NACA Ն general practitioners showed increased numbers of 4 there was no difference in the number of labo - wrong diagnoses in patients with NACA Ն 4. This ratory tests blood draws ordered. Hospital stays of effect was highly statistically significant for para - patients admitted with a correct diagnosis were medics (p < 0.001) and to a lesser extent for gen - significantly shorter compared to patients admit - eral practitioners (p = 0.009, Table 3). ted with a wrong or missing diagnosis. This find - The correlation of accuracy of diagnosis to ing was independent of the NACA Score (Table years of clinical experience and postgraduate 2). training showed a statistically highly significant in - Overall (NACA 1 – 7), emergency physicians, crease for emergency physicians (p < 0.001). After paramedics and general practitioners made pre - PGY 6, they reached an accuracy of prehospital hospital diagnoses with a comparable accuracy of diagnosis of > 90% in our study sample. A similar approximately 50% (p = 0.139, Table 3). Emer - effect could not be shown for paramedics or for gency physicians made a diagnosis in > 99% of general practitioners. Both remained at a level of the cases whereas paramedics and general practi - accuracy of about 50% even as they gained more tioners made no diagnosis in > 30% of the cases. clinical experience. In patients without a life-threatening event Over all (NACA 1 – 7), emergency physicians, (NACA < 4), diagnoses made by emergency physi - paramedics and general practitioners assessed cians were accurate in 45% of the cases. In more NACA Scores with a comparable accuracy of ap - severe cases (NACA Ն 4), emergency physicians proximately 50% (p = 0.096). Emergency physi - increased their accuracy of diagnosis to 60% cians underestimated NACA scores less often com -

Table 3. Accuracy of prehospital diagnosis by each group of Table 4. Accuracy of prehospital assessment of severity of first responders in percent, (Confidence Interval, CI = 95%), cases by each group of first responders in percent, (Confidence sub analysis for patients with a potentially life threatening Interval, CI = 95%), sub analysis for patients with a potentially injury or disease (NACA Ն 4) life threatening injury or disease (NACA Ն 4) EP PM GP p Total EP PM GP p Total %%%values number %%%values number (CI) (CI) (CI) of cases (CI) (CI) (CI) of cases Global Global Correct 55 (49-60) 48 (45-52) 47 (41-53) 0.139 612 Correct 50 (44-56) 47 (43-51) 41 (36-47) 0.096 575 Incorrecto 45 (39-51) 17 (14-20) 21 (17-26) < 0.001 297 Overestimated 20 (16-26) 9 (7-11) 3 (3-8) < 0.001 130 Missing diagnosis 1 (0-2) 35 (32-39) 32 (27-37) < 0.001 332 Underestimated 29 (24-35) 44 (41-48) 54 (48-60) < 0.001 536 Sub analysis of patients Ն NACA 4 Sub analysis of patients Ն NACA 4 Correct 60 (52-67) 50 (44-55) 49 (40-57) 0.062 307 Correct 49(42-56) 11 (8-15) 7 (4-13) < 0.001 124 Wrong 40 (33-47) 26 (22-32) 28 (21-36) 0.009 180 Overestimated 10 (6-15) > 1 (0-2) 1 (0-4) < 0.001 19 Missing diagnosis < 1 (0-3) 24 (19-30) 24 (17-31) < 0.001 100 Underestimated 41(34-49) 89 (85-92) 92 (86-96) < 0.001 444 EP = Emergency physicians; PM = Paramedics; GP = General practitio - EP = Emergency physicians; PM = Paramedics; GP = General practitio - ners. ners.

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pared to paramedics or general practitioners in Switzerland in emergency medicine for general (p < 0.001). In patients NACA Ն 4 emergency practitioners is brief (a four day series of courses physicians were more likely to correctly assess within five years of post graduate education). If NACA scores (49%) than paramedics (11%) and general practitioners continue to participate in the general practitioners (7%; p < 0.001). Additionally Swiss EMS system, their education in prehospital paramedics and general practitioners underesti - emergency medicine needs to be extended. As mated the severity of cases in about 90% of the shown for emergency physicians, postgraduate patients NACA Ն 4 (p < 0.001, Table 4). continuous education can improve accuracy of di - agnosis and thereby reduce mortality. The positive effect of training in decision-making is also reflect - Discussion ed in the low number of cases where emergency physicians did not make a diagnosis (Table 3) 27,28 . A correct diagnosis made in the prehospital The fact that paramedics and general practitioners emergency situation decreases mortality and the underestimated life-threatening events in 90% of length of stay in the hospital. To make a correct their patients with NACA Ն 4 is disturbing (Table diagnosis in the prehospital emergency situation 4). Patients with NACA Ն 4 may die if diseases or does not increase the time on scene spent with injury patterns are not recognized correctly. This the patient. In patients admitted without a poten - issue needs to be addressed in future education of tially life threatening injury or disease (NACA < 4), these two groups of first responders. a correct diagnosis even decreases the number of The strength of the changes in the Swiss EMS blood draws laboratory values ordered in the first system over the last two decades lie in an in - 24 hours. Therefore education in prehospital creased accuracy of prehospital diagnosis and a emergency medicine for any group of first respon - decreased underestimation of severity of cases, ders should focus on making a correct diagnosis. both due to the integration of highly trained Overall first responders evaluated in this study emergency physicians. These results are compara - sample showed a surprisingly low accuracy of di - ble to the study of Klemmen et al., where they agnoses of about 50%. For emergency physicians found a decrease in mortality at hospital admis - we found a strong positive correlation between sion for patients with traumatic brain injury after diagnostic accuracy and clinical experience and the introduction of emergency physicians into the postgraduate education. After six years of clinical EMS system 29 . A higher number of correct diag - practice as emergency physicians, they reached a noses may also be the reason why Calvagno et al. diagnostic accuracy rate >90%. This finding is found an association between patients transport - supported by other studies 21,25 . In many European ed by a Helicopter EMS and survival, in their re - countries, the minimum requirement for residency cently published database analysis 14 . in on of the main medical specialties of acute One limitation in our study is the geographical medicine (e.g. anesthesiology, surgery, internal setting of the alpine region in Switzerland. We medicine) is five to six years. Bedside-structured could not evaluate the influence of accuracy of di - training of competencies within a resident train - agnosis on in terms of the selection of the ing program in emergency medicine and suffi - receiving trauma center. This alpine geographical cient patient contact seem to be of great impor - setting requires that patients are stabilized in a tance for providing accurate prehospital Level lll trauma center before transport to a Level diagnoses. Specialized emergency medical train - l trauma center as a standard practice. A second ing can significantly improve diagnostic accuracy limitation is our identification of the diagnosis at in a prehospital emergency setting 26 . A similar in - discharge as "accurate." This might not have been crease in accuracy of diagnosis was not found true for every case. A third limitation is the possi - with paramedics or general practitioners. This ble loss of information from the unrecorded “spo - suggests that a broad and solid medical education ken record” in the ED. Nevertheless, we believe in emergency medicine is necessary to improve that evaluating all 1241 diagnoses in text-form re - prehospital diagnostic accuracy above 50%. The flects an accurate picture of what was reported to three years of education for paramedics may not the team in the hospital. provide enough medical training to recognize A correct diagnosis made in a prehospital more complex medical problems or injury pat - emergency situation by a first responder decreases terns. More postgraduate training with a focus on mortality and the length of stay in the hospital. patient assessment and correct diagnosis could To make a correct diagnosis in the prehospital set - improve their performance. The required training ting does not increase the time on scene spent

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432 Emergencias 2012; 24: 426-432 COMPARING PERFORMANCE AND IMPACT OF FIRST RESPONDERS ON OUTCOME IN PREHOSPITAL EMERGENCY MEDICINE IN SWITZERLAND

Rendimiento e impacto de los primeros respondedores en la evolución de la medicina de emergencias prehospitalaria en Suiza

Urwyler N, Theiler L, Schönhofer J, Kämpfen B, Stave C, Greif R Introducción: Existen resultados contradictorios sobre la eficacia de los primeros respondedores en emergencias extra - hospitalarias. Este estudio evalúa el rendimiento y el impacto de estos profesionales en el resultado. Método: Es un estudio de cohortes retrospectivo donde se evalúa la precisión de los médicos de emergencia, paramé - dicos y médicos generales. Se comparó el diagnóstico realizado en la situación de emergencia prehospitalaria frente al diagnóstico al alta del hospital. El resultado primario fue el impacto de la precisión del diagnóstico sobre la mortalidad. Los resultados secundarios fueron: 1) tiempo en la escena, y 2) duración de la hospitalización. Se valoró especialmente la influencia de la experiencia clínica y de la formación de postgrado. Resultados: Se evaluaron 1.241 diagnósticos. Los pacientes ingresados con el diagnóstico incorrecto o sin diagnóstico mostraron un mayor riesgo de mortalidad (p = 0,04, OR 1,9, IC 1,04-3,34). El tiempo en la escena y el tiempo de in - greso hospitalario fue menor si el diagnóstico fue el correcto. Los médicos de emergencias, paramédicos y médicos ge - neralistas diagnostican con una precisión comparable (p = 0,139), pero en el caso de los médicos de emergencias se demostró un aumento significativo de la precisión en relación a sus años de experiencia (p < 0,001). Después de 6 años de experiencia, alcanzan una precisión diagnóstica mayor del 90%. Este efecto no se pudo demostrar en paramé - dicos ni en médicos generales. Conclusión: El diagnóstico prehospitalario correcto reduce la mortalidad y la estancia hospitalaria. Los médicos forma - dos en emergencias tienen una nivel de precisión diagnóstica mayor. Por lo tanto, estos médicos deben ser incluidos en el sistema de emergencias prehospitalarias, sobre todo para los casos más graves. [Emergencias 2012;24:426-432]

Palabras clave: Precisión diagnóstica. Medicina en emergencia prehospitalaria. Servicios médicos de emergencias. Mé - dicos de emergencias. Paramédicos. Formación postgrado.

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