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1.  Using genetic algorithms to optimise current and future health planning - the example of ambulance locations 
Background
Ambulance response time is a crucial factor in patient survival. The number of emergency cases (EMS cases) requiring an ambulance is increasing due to changes in population demographics. This is decreasing ambulance response times to the emergency scene. This paper predicts EMS cases for 5-year intervals from 2020, to 2050 by correlating current EMS cases with demographic factors at the level of the census area and predicted population changes. It then applies a modified grouping genetic algorithm to compare current and future optimal locations and numbers of ambulances. Sets of potential locations were evaluated in terms of the (current and predicted) EMS case distances to those locations.
Results
Future EMS demands were predicted to increase by 2030 using the model (R2 = 0.71). The optimal locations of ambulances based on future EMS cases were compared with current locations and with optimal locations modelled on current EMS case data. Optimising the location of ambulance stations locations reduced the average response times by 57 seconds. Current and predicted future EMS demand at modelled locations were calculated and compared.
Conclusions
The reallocation of ambulances to optimal locations improved response times and could contribute to higher survival rates from life-threatening medical events. Modelling EMS case 'demand' over census areas allows the data to be correlated to population characteristics and optimal 'supply' locations to be identified. Comparing current and future optimal scenarios allows more nuanced planning decisions to be made. This is a generic methodology that could be used to provide evidence in support of public health planning and decision making.
doi:10.1186/1476-072X-9-4
PMCID: PMC2828441  PMID: 20109172
2.  Emergency department overcrowding and ambulance transport delays for patients with chest pain 
Objective
Emergency department overcrowding sometimes results in diversion of ambulances to other locations. We sought to determine the resulting prehospital delays for cardiac patients.
Methods
Data on consecutive patients with chest pain who were transported to Toronto hospitals by ambulance were obtained for a 4-month period in 1997 and a 4-month period in 1999, which represented periods of low and high emergency department overcrowding respectively. Multivariate analyses were used to model 90th percentile system response (initiation of 9-1-1 call to arrival on scene), on-scene (arrival on scene to departure from scene) and transport (departure from scene to arrival at hospital) intervals. Predictor variables were study period (1997 or 1999), day of the week, time of day, geographic location of the patient, dispatch priority, case severity, return priority and number of other patients with chest pain transported within 2 hours of the index transport.
Results
A total of 3609 patients (mean age 66.3 years, 50.3% female) who met the study criteria were transported by ambulance during the 2 study periods. There were no significant differences in patient characteristics between the 2 periods, despite the fact that more patients were transported during the second period (p < 0.001). The 90th percentile system response interval increased by 11.3% from the first to the second period (9.7 v. 10.8 min, p < 0.001), whereas the on-scene interval decreased by 8.2% (28.0 v. 25.7 min, p < 0.001). The longest delay was in the transport interval, which increased by 28.4% from 1997 to 1999 (13.4 v. 17.2 min, p < 0.001). In multivariate analyses, the study period (1997 v. 1999) remained a significant predictor of longer transport interval (p < 0.001) and total prehospital interval (p = 0.004).
Interpretation
An increase in overcrowding in emergency departments was associated with a substantial increase in the system response interval and the ambulance transport interval for patients with chest pain.
PMCID: PMC140469  PMID: 12566332
3.  Pre-hospital care time intervals among victims of road traffic injuries in Iran. A cross-sectional study 
BMC Public Health  2010;10:406.
Background
Road traffic injuries (RTIs) are a major public health problem, requiring concerted efforts both for their prevention and a reduction of their consequences. Timely arrival of the Emergency Medical Service (EMS) at the crash scene followed by speedy victim transportation by trained personnel may reduce the RTIs' consequences. The first 60 minutes after injury occurrence - referred to as the "golden hour"- are vital for the saving of lives. The present study was designed to estimate the average of various time intervals occurring during the pre-hospital care process and to examine the differences between these time intervals as regards RTIs on urban and interurban roads.
Method
A retrospective cross-sectional study was designed and various time intervals in relation to pre-hospital care of RTIs identified in the ambulance dispatch centre in Urmia, Iran from 20 March 2005 to 20 March 2007. All cases which resulted in ambulance dispatches were reviewed and those that had complete data on time intervals were analyzed.
Results
In total, the cases of 2027 RTI victims were analysed. Of these, 61.5 % of the subjects were injured in city areas. The mean response time for city locations was 5.0 minutes, compared with 10.6 minutes for interurban road locations. The mean on-scene time on the interurban roads was longer than on city roads (9.2 vs. 6.1 minutes, p < 0.001). Mean transport times from the scene to the hospital were also significantly longer for interurban incidents (17.1 vs. 6.3 minutes, p < 0.001). The mean of total pre-hospital time was 37.2 (+/-17.2) minutes with a median of 32.0. Overall, 72.5% of the response interval time was less than eight minutes.
Conclusion
The response, transport and total time intervals among EMS responding to RTI incidents were longer for interurban roads, compared to the city areas. More research should take place on needs-to and access-for EMS on city and interurban roads. The notification interval seems to be a hidden part of the post-crash events and indirectly affects the "golden hour" for victim management and it needs to be measured through the establishment of the surveillance systems.
doi:10.1186/1471-2458-10-406
PMCID: PMC2918553  PMID: 20618970
4.  Computer assisted assessment and advice for "non-serious" 999 ambulance service callers: the potential impact on ambulance despatch 
Emergency Medicine Journal : EMJ  2003;20(2):178-183.
Design: Pragmatic controlled trial. Calls identified using priority dispatch protocols as non-serious were allocated to intervention and control groups according to time of call. Ambulance dispatch occurred according to existing procedures. During intervention sessions, nurses or paramedics within the control room used a computerised decision support system to provide telephone assessment, triage and, if appropriate, offer advice to permit estimation of the potential impact on ambulance dispatch.
Setting: Ambulance services in London and the West Midlands.
Subjects: Patients for whom emergency calls were made to the ambulance services between April 1998 and May 1999 during four hour sessions sampled across all days of the week between 0700 and 2300.
Main outcome measures: Triage decision, ambulance cancellation, attendance at an emergency department.
Results: In total, there were 635 intervention calls and 611 controls. Of those in the intervention group, 330 (52.0%) were triaged as not requiring an emergency ambulance, and 119 (36.6%) of these did not attend an emergency department. This compares with 55 (18.1%) of those triaged by a nurse or paramedic as requiring an ambulance (odds ratio 2.62; 95% CI 1.78 to 3.85). Patients triaged as not requiring an emergency ambulance were less likely to be admitted to an inpatient bed (odds ratio 0.55; 95% CI 0.33 to 0.93), but even so 30 (9.2%) were admitted. Nurses were more likely than paramedics to triage calls into the groups classified as not requiring an ambulance. After controlling for age, case mix, time of day, day of week, season, and ambulance service, the results of a logistic regression analysis revealed that this difference was significant with an odds ratio for nurses:paramedics of 1.28 (95% CI 1.12 to 1.47).
Conclusions: The findings indicate that telephone assessment of Category C calls identifies patients who are less likely to require emergency department care and that this could have a significant impact on emergency ambulance dispatch rates. Nurses were more likely than paramedics to assess calls as requiring an alternative response to emergency ambulance despatch, but the extent to which this relates to aspects of training and professional perspective is unclear. However, consideration should be given to the acceptability, reliability, and cost consequences of this intervention before it can be recommended for full evaluation.
doi:10.1136/emj.20.2.178
PMCID: PMC1726071  PMID: 12642540
5.  Evaluation of emergency ambulance characteristics under several criteria. 
Health Services Research  1979;14(2):160-176.
A methodology and analysis are presented for evaluating response time characteristics of emergency ambulance systems. The methodology is based on a Monte Carlo simulation technique and a heuristic optimal-seeking technique for locating emergency ambulances under several criteria based on response time distribution. Optimization criteria include minimum mean system response time, minimum system fractile response time and minimum level-loaded response time. The evaluation methodology is applied to the metropolitan area of Los Angeles County. Ambulance response characteristics and loads are discussed in detail. From these results alternative dispatch polices can be evaluated. Complementing the analysis is a presentation of a sensitivity analysis and an analysis of existing ambulance sites. Unique to the methodology is the adaption of the heuristic optimal-seeking technique to include any of the three criteria and the effectiveness of the methodology for analyzing small or large ambulance systems.
PMCID: PMC1072111  PMID: 511579
6.  Influence of socioeconomic factors on medically unnecessary ambulance calls 
Background
Unnecessary ambulance use has become a socioeconomic problem in Japan. We investigated the possible relations between socioeconomic factors and medically unnecessary ambulance calls, and we estimated the incremental demand for unnecessary ambulance use produced by socioeconomic factors.
Methods
We conducted a self-administered questionnaire-based survey targeting residents of Yokohama, Japan. The questionnaire included questions pertaining to socioeconomic characteristics, dichotomous choice method questions pertaining to ambulance calls in hypothetical nonemergency situations, and questions on the city's emergency medical system. The probit model was used to analyze the data.
Results
A total of 2,029 out of 3,363 targeted recipients completed the questionnaire (response rate, 60.3%). Probit regression analyses showed that several demographic and socioeconomic factors influence the decision to call an ambulance. Male respondents were more apt than female respondents to state that they would call an ambulance in nonemergency situations (p < 0.05). Age was an important factor influencing the hypothetical decision to call an ambulance (p < 0.05); elderly persons were more apt than younger persons to state that they would call an ambulance. Possession of a car and hesitation to use an ambulance negatively influenced the hypothetical decision to call an ambulance (p < 0.05). Persons who do not have a car were more likely than those with a car to state that they would call an ambulance in unnecessary situations.
Conclusion
Results of the study suggest that several socioeconomic factors, i.e., age, gender, household income, and possession of a car, influence a person's decision to call an ambulance in nonemergency situations. Hesitation to use an ambulance and knowledge of the city's primary emergency medical center are likely to be important factors limiting ambulance overuse. It was estimated that unnecessary ambulance use is increased approximately 10% to 20% by socioeconomic factors.
doi:10.1186/1472-6963-7-120
PMCID: PMC1950705  PMID: 17655772
7.  Developing an analytical tool for evaluating EMS system design changes and their impact on cardiac arrest outcomes: combining geographic information systems with register data on survival rates 
Background
Out-of-hospital cardiac arrest (OHCA) is a frequent and acute medical condition that requires immediate care. We estimate survival rates from OHCA in the area of Stockholm, through developing an analytical tool for evaluating Emergency Medical Services (EMS) system design changes. The study also is an attempt to validate the proposed model used to generate the outcome measures for the study.
Methods and results
This was done by combining a geographic information systems (GIS) simulation of driving times with register data on survival rates. The emergency resources comprised ambulance alone and ambulance plus fire services. The simulation model predicted a baseline survival rate of 3.9 per cent, and reducing the ambulance response time by one minute increased survival to 4.6 per cent. Adding the fire services as first responders (dual dispatch) increased survival to 6.2 per cent from the baseline level. The model predictions were validated using empirical data.
Conclusion
We have presented an analytical tool that easily can be generalized to other regions or countries. The model can be used to predict outcomes of cardiac arrest prior to investment in EMS design changes that affect the alarm process, e.g. (1) static changes such as trimming the emergency call handling time or (2) dynamic changes such as location of emergency resources or which resources should carry a defibrillator.
doi:10.1186/1757-7241-21-8
PMCID: PMC3579715  PMID: 23415045
Out-of-hospital cardiac arrest; Defibrillation; Response time; Survival rate; Geographic information systems; Fire services
8.  General practitioner attendance at emergencies notified to ambulance control. 
For two years doctors from a small village went to the scene of emergency calls received by ambulance control. On 80% of the occasions when the doctor was called at the same time as the ambulance was dispatched the doctor arrived before the ambulance. There were 24 incidents, 16 of which were road traffic accidents. In two cases the doctor established a clear airway in an unconscious patient before the ambulance arrived. Two patients were trapped in their vehicles and were given parenteral analgesics. Four patients required intravenous fluids. The call out system provided first aid for patients before the ambulance arrived and medical assistance to the emergency services at serious accidents. Patients who did not require hospital attention could be examined and treated at the scene, making the ambulance available for other duties and reducing the number of patients taken to the hospital accident and emergency department.
PMCID: PMC1442003  PMID: 6430397
9.  Prehospital Management of Gunshot Patients at Major Trauma Care Centers: Exploring the Gaps in Patient Care 
Trauma Monthly  2013;18(2):62-66.
Background
Prehospital management of gunshot-wounded (GW) patients influences injury-induced morbidity and mortality.
Objectives
To evaluate prehospital management to GW patients emphasizing the protocol of patient transfer to appropriate centers.
Patients and Methods
This prospective study, included all GW patients referred to four major, level-I hospitals in Mashhad, Iran. We evaluated demographic data, triage, transport vehicles of patients, hospitalization time and the outcome.
Results
There were 66 GW patients. The most affected body parts were extremities (60.6%, n = 40); 59% of cases (n = 39) were transferred to the hospitals with vehicles other than an ambulance. Furthermore, 77.3% of patients came to the hospitals directly from the site of event, and 22.7% of patients were referred from other medical centers. EMS action intervals from dispatchers to scene departure was not significantly different from established standards; however, arrival to hospital took longer than optimal standards. Additionally, time spent at emergency wards to stabilize vital signs was significantly less in patients who were transported by EMS ambulances (P = 0.01), but not with private ambulances (P = 0.47). However, ambulance pre-hospital care was not associated with a shorter hospital stay. Injury Severity was the only determinant of hospital stay duration (β = 0.36, P = 0.01) in multivariate analysis.
Conclusions
GW was more frequent in extremities and the most patients were directly transferred from the accident site. EMS (but not private) ambulance transport improved patients' emergency care and standard time intervals were achieved by EMS; however more than a half of the cases were transferred by vehicles other than an ambulance. Nevertheless, ambulance transportation (either by EMS or by private ambulance) was not associated with a shorter hospital stay. This showed that upgrade of ambulance equipment and training of private ambulance personnel may be needed.
doi:10.5812/traumamon.10438
PMCID: PMC3860682  PMID: 24350154
Wounds, Gunshot; Triage; Emergency Medical Services; Wounds and Injuries; Iran
10.  Emergency Medical Transportation—A Survey of California Ambulance Operations 
California Medicine  1972;116(2):35-43.
The most urgent recommendation expressed by physicians, Red Cross officials, ambulance operators and others polled in this ambulance survey was to make much more emergency medical care training available to ambulance personnel. Very few sick and injured receive first aid before an ambulance arrives. Therefore there is also an urgent need to train and motivate the public to provide first aid at the scene of the emergency. Urban ambulances usually respond within 10 minutes, but often rural ambulances take more than 30 minutes to reach an emergency. It is during this interim that lives which could be saved by prompt first aid are lost. Little use has been made of aircraft as emergency ambulances; in 1968, only one emergency trip in 1500 was made by helicopter. Also, California has fewer ambulances which make fewer emergency trips on a population basis than the country at large.
Communications at all levels need attention. Seventy-eight percent of the ambulance operations serving the public are not listed among the emergency numbers on the inside front page of telephone directories. Less than ten percent of ambulances have direct radio communication with hospitals.
In California most ambulance services are commercially operated and there are formidable financial problems which must be solved before these services can be brought into place as a part of the emergency medical care system.
PMCID: PMC1518233  PMID: 5059665
11.  Evaluation of an algorithm for estimating a patient's life threat risk from an ambulance call 
Background
Utilizing a computer algorithm, information from calls to an ambulance service was used to calculate the risk of patients being in a life-threatening condition (life threat risk), at the time of the call. If the estimated life threat risk was higher than 10%, the probability that a patient faced a risk of dying was recognized as very high and categorized as category A+. The present study aimed to review the accuracy of the algorithm.
Methods
Data collected for six months from the Yokohama new emergency system was used. In the system, emergency call workers interviewed ambulance callers to obtain information necessary to assess triage, which included consciousness level, breathing status, walking ability, position, and complexion. An emergency patient's life threat risk was then estimated by a computer algorithm applying logistic models. This study compared the estimated life threat risk occurring at the time of the emergency call to the patients' state or severity of condition, i.e. death confirmed at the scene by ambulance crews, resulted in death at emergency departments, life-threatening condition with occurrence of cardiac and/or pulmonary arrest (CPA), life-threatening condition without CPA, serious but not life-threatening condition, moderate condition, and mild condition. The sensitivity, specificity, predictive values, and likelihood ratios of the algorithm for categorizing A+ were calculated.
Results
The number of emergency dispatches over the six months was 73,992. Triage assessment was conducted for 68,692 of these calls. The study targets account for 88.8% of patients who were involved in triage calls. There were 2,349 cases where the patient had died or had suffered CPA. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of the algorithm at predicting cases that would result in a death or CPA were 80.2% (95% confidence interval: 78.6% - 81.8%), 96.0% (95.8% - 96.1%), 42.6% (41.1% - 44.0%), 99.2% (99.2% - 99.3%), 19.9 (18.8 - 21.1), and 0.21 (0.19 - 0.22), respectively.
Conclusion
A patient's life threat risk was quantitatively assessed at the moment of the emergency call with a moderate level of accuracy.
doi:10.1186/1471-227X-9-21
PMCID: PMC2770982  PMID: 19845937
12.  Medical emergency motorcycle – is it useful in a Scandinavian Emergency Medical Service? 
Background
Medical emergency motorcycles (MEM) can be used in time-critical conditions like cardiac arrest and multi-traumatized patients in an attempt to reduce the response time. Other potential benefits with MEM are more efficient patient evaluation, reduction of unnecessary EMS car ambulance missions and reduced cost. The potential benefits have been evaluated in this study. The incidence of accidents when operating the vehicle was also of interest.
Methods
A prospective study was performed when MEM was introduced as a trial in an urban ambulance service in Norway.
Results
A total of 703 MEM missions were registered in the period. The mean emergency driving time was significantly shorter for the MEM than for the ambulance car located at the same station (6 min 24 seconds vs. 6 min 54 seconds). In addition to time-critical conditions, the MEM was used to evaluate patients when the need for emergency medical assistance was uncertain, and this practice lead to a reduced number of unnecessary car ambulance missions. No accidents involving the MEM were registered in the study period. The hourly cost of running the MEM was € 29 vs. € 75 for a car ambulance. However, the actual cost benefit is smaller since the weather conditions make it impossible to run a MEM in wintertime.
Conclusion
The small reduction in driving time when using a MEM instead of a car ambulance was statistically significant but probably of little clinical importance. The number of unnecessary car ambulance missions was reduced. It was cheaper to operate a MEM than a car ambulance, but the cost-effectiveness was reduced since the MEM could not operate 12 months a year. The lack of accidents may be contributed to the extensive training of the drivers and the fact that the vehicle was operated in daylight only.
doi:10.1186/1757-7241-17-9
PMCID: PMC2652419  PMID: 19239681
13.  Prehospital digital photography and automated image transmission in an emergency medical service – an ancillary retrospective analysis of a prospective controlled trial 
Background
Still picture transmission was performed using a telemedicine system in an Emergency Medical Service (EMS) during a prospective, controlled trial. In this ancillary, retrospective study the quality and content of the transmitted pictures and the possible influences of this application on prehospital time requirements were investigated.
Methods
A digital camera was used with a telemedicine system enabling encrypted audio and data transmission between an ambulance and a remotely located physician. By default, images were compressed (jpeg, 640 x 480 pixels). On occasion, this compression was deactivated (3648 x 2736 pixels). Two independent investigators assessed all transmitted pictures according to predefined criteria. In cases of different ratings, a third investigator had final decision competence. Patient characteristics and time intervals were extracted from the EMS protocol sheets and dispatch centre reports.
Results
Overall 314 pictures (mean 2.77 ± 2.42 pictures/mission) were transmitted during 113 missions (group 1). Pictures were not taken for 151 missions (group 2). Regarding picture quality, the content of 240 (76.4%) pictures was clearly identifiable; 45 (14.3%) pictures were considered “limited quality” and 29 (9.2%) pictures were deemed “not useful” due to not/hardly identifiable content. For pictures with file compression (n = 84 missions) and without (n = 17 missions), the content was clearly identifiable in 74% and 97% of the pictures, respectively (p = 0.003). Medical reports (n = 98, 32.8%), medication lists (n = 49, 16.4%) and 12-lead ECGs (n = 28, 9.4%) were most frequently photographed. The patient characteristics of group 1 vs. 2 were as follows: median age – 72.5 vs. 56.5 years, p = 0.001; frequency of acute coronary syndrome – 24/113 vs. 15/151, p = 0.014. The NACA scores and gender distribution were comparable. Median on-scene times were longer with picture transmission (26 vs. 22 min, p = 0.011), but ambulance arrival to hospital arrival intervals did not differ significantly (35 vs. 33 min, p = 0.054).
Conclusions
Picture transmission was used frequently and resulted in an acceptable picture quality, even with compressed files. In most cases, previously existing “paper data” was transmitted electronically. This application may offer an alternative to other modes of ECG transmission. Due to different patient characteristics no conclusions for a prolonged on-scene time can be drawn. Mobile picture transmission holds important opportunities for clinical handover procedures and teleconsultation.
doi:10.1186/1757-7241-21-3
PMCID: PMC3568016  PMID: 23324531
Telemedicine; Teleconsultation; Digital image; Emergency medical service; Picture transmission; Photo transmission
14.  Management of myocardial infarction: implications for current policy derived from the Nottingham Heart Attack Register. 
British Heart Journal  1992;67(3):255-262.
OBJECTIVE--A register of patients with heart attacks in the Nottingham Health District has been maintained since 1973. Data from 1982 to 1984 inclusive, a period before trials of thrombolytic therapy started in Nottingham, were analysed to provide background information for the introduction of a policy of routine thrombolysis for appropriate patients. DESIGN--Data were collected prospectively on all patients transported to hospital in the Nottingham Health District with suspected myocardial infarction in the years 1982-84 and on patients treated at home during that time. SETTING--Two district general hospitals responsible for all emergency admissions in the health district. PATIENTS--6712 patients admitted to hospital with suspected myocardial infarction and 1887 patients found dead on arrival at hospital. Approximately 1500 patients in whom a myocardial infarction was suspected were treated at home, but only 125 were identified who had a definite or probable infarction. RESULTS--Among the patients admitted within 24 hours of the onset of symptoms, the median delay from onset to hospital admission was 174 minutes; 25% of patients were admitted within 91 minutes. The only factor that seemed to affect the time taken was the patient's decision to call a general practitioner or an emergency ambulance. If a general practitioner referred the patient to hospital the median delay was 247 minutes, compared with 100 minutes when the patient summoned an ambulance. Ninety three per cent of all patients were transported by ambulance. The median time from the call for the ambulance to hospital arrival was 29 minutes. Once a patient was admitted to hospital, the time to admission and general practitioner involvement seemed relatively unimportant as predictors of outcome. Patients admitted more than nine hours after onset of symptoms with a diagnosis of definite or probable infarction had a poorer outcome than those admitted earlier (in-hospital mortality 22.4% v 13.1%). The fatality rates of those admitted to a coronary care unit or to an ordinary medical ward are similar. CONCLUSION--Although the introduction of thrombolytic therapy has brought with it an increased awareness of the need to minimise any delay in time to admission, it seems that in a predominantly urban area like Nottingham, patients with a suspected heart attack will continue to be admitted to hospital most quickly if an ambulance crew rather than a general practitioner is called. Because the ambulance crew was in contact with such patients for only a short time it seems unlikely that administration of a thrombolytic drug in the ambulance would be helpful.
PMCID: PMC1024802  PMID: 1554544
15.  Cardiac arrest in Ontario: circumstances, community response, role of prehospital defibrillation and predictors of survival. 
OBJECTIVES: To describe the patient characteristics, circumstances and community response in cases of out-of-hospital cardiac arrest; to evaluate the effect on survival of the introduction of prehospital defibrillation; and to identify factors that predict survival. DESIGN: Population-based before-and-after clinical trial. SETTING: Five Ontario communities: London, Sudbury, the Greater Niagara region, Kingston and Ottawa. PATIENTS: A consecutive sample of 1510 primary cardiac arrest patients who were transported to hospital by ambulance over 2 years. INTERVENTION: The use of defibrillators by ambulance attendants. MAIN OUTCOME MEASURES: Patient characteristics (sex and age), circumstances of arrest (place, whether arrest was witnessed and cardiac rhythm), citizen response (whether cardiopulmonary resuscitation [CPR] was started by a bystander, time to access to emergency medical services and time to initiation of CPR), emergency medical services response (ambulance response time, time to initiation of CPR and time to rhythm analysis with defibrillator) and survival rates. MAIN RESULTS: A total of 92.1% of the patients were 50 years of age or older, and 68.3% were men. Overall, 79.6% of the arrests occurred in the home. The average ambulance response time for witnessed cases was 7.8 minutes. The overall survival rate was 2.5%. The survival rates before and after defibrillators were introduced were similar, and the general functional outcome of the survivors did not differ significantly between the two phases. Factors predicting survival included patient's age, ambulance response time and whether CPR was started before the ambulance arrived. CONCLUSIONS: The survival rate was lower than expected. The availability of prehospital defibrillation did not affect survival. To improve survival rates after cardiac arrest ambulance response times must be reduced and the frequency of bystander-initiated CPR increased. Once these changes are in place a beneficial effect from advanced manoeuvres such as prehospital defibrillation may be seen.
PMCID: PMC1336161  PMID: 1623465
16.  Emergency (999) calls to the ambulance service that do not result in the patient being transported to hospital: an epidemiological study 
Emergency Medicine Journal : EMJ  2002;19(5):449-452.
Methods: The first 500 consecutive non-transported patients from 1 March 2000 were identified from the ambulance service command and control data. Epidemiological and clinical data were then obtained from the patient report form completed by the attending ambulance crew and compared with the initial priority dispatch (AMPDS) code that determined the urgency of the ambulance response.
Results: Data were obtained for 498 patients. Twenty six per cent of these calls were assigned an AMPDS delta code (the most urgent category) at the time the call was received. Falls accounted for 34% of all non-transported calls. This group of patients were predominantly elderly people (over 70 years old) and the majority (89%) were identified as less urgent (coded AMPDS alpha or bravo) at telephone triage. The mean time that an ambulance was committed to each non-transported call was 34 minutes.
Conclusions: This study shows that falls in elderly people account for a significant proportion of non-transported 999 calls and are often assigned a low priority when the call is first received. There could be major gains if some of these patients could be triaged to an alternative response, both in terms of increasing the ability of the ambulance service to respond faster to clinically more urgent calls and improving the cost effectiveness of the health service. The AMPDS priority dispatch system has been shown to be sensitive but this study suggests that its specificity may be poor, resulting in rapid responses to relatively minor problems. More research is required to determine whether AMPDS prioritisation can reliably and safely identify 999 calls where an alternative to an emergency ambulance would be a more appropriate response.
doi:10.1136/emj.19.5.449
PMCID: PMC1725980  PMID: 12205005
17.  Telephone triage of cardiac emergency calls by dispatchers: a prospective study of 1386 emergency calls. 
British Heart Journal  1994;71(5):440-445.
OBJECTIVES--To evaluate the handling of potential cardiac emergency calls by dispatchers, to determine their final diagnosis and urgency, and to determine the value of the main complaint in predicting urgency and the ability of the dispatchers to recognise non-urgent conditions. DESIGN--Prospective data collection and recording of main complaint of emergency calls placed via the 06-11 alarm telephone number with follow up to hospital when the patients were transported and the general practitioner when they were not. SETTING--Dispatch centres of the emergency medical services in Amsterdam (urban area) and Enschede (rural area). PATIENTS--1386 consecutive adult subjects of emergency calls placed by citizens about chest problems or unconsciousness not caused by injury. MAIN OUTCOME MEASURES--Frequency of characteristics of the calls, outcome in diagnosis, and assessment of urgency. RESULTS--69 (5%) patients were dead when the ambulance arrived. Diagnosis was established in 1071 patients (77%). The disorders most often reported were cardiac, with acute ischaemia in 15% of all subjects. In 28% of cases and for each presenting complaint no organic explanation was found. Overall 39% of all emergency calls were urgent; the urgency rate was lowest for calls for people with abdominal discomfort. Dispatchers correctly identified 90% of the non-urgent calls, but 55% of the calls that they identified as urgent proved to be non-urgent. CONCLUSION--Currently, direct dialling for an ambulance without the intervention of a general practitioner imposes a high work load on emergency systems and hospitals because triage by dispatchers is not sufficiently accurate. It may be possible to increase the accuracy of triage by developing and testing decision algorithms.
PMCID: PMC483720  PMID: 8011407
18.  Attributing the responsibility for ambulating patients: A qualitative study 
Background
Functional decline has been identified as a leading negative outcome of hospitalization for older person. Functional decline is defined as a loss in ability to perform activities of daily living including a loss of independent ambulation. In the hospital literature, a patient’s loss in ability to independently ambulate during the hospital stay varies between 15 and 59%. Lack of ambulation and deconditioning effects of bed rest are one of the most predictable causes of loss of independent ambulation in hospitalized older persons. Nurses have been identified as the professional most capable of promoting walking independence in the hospital setting. However, nurses do not routinely walk patients.
Objective
The purpose of this study was to explore the relationship between nurses’ attributions of responsibility for ambulating hospitalized patients and their decisions about whether to ambulate.
Methods
A descriptive, secondary analysis of data gathered for a parent study was conducted. Grounded dimensional analysis was used to analyze the data. Participants consisted of 25 registered nurses employed on medical or surgical units from two urban hospitals in the United States.
Results
Nurses fell into two groups: those who claimed ambulation of patients within their responsibility of practice and those who attributed the responsibility to another discipline. Nurses who claimed responsibility for ambulation focused on patient independence and psychosocial well-being. This resulted in actions related to collaborating with physical therapy, determining the appropriateness of activity orders, diminishing the risk and adjusting to resource availability. Nurses who attributed the responsibility deferred decisions about initiating ambulation to either physical therapy or medicine. This resulted in actions related to waiting, which involved, waiting for physical therapy clearance, physician orders, risks to decrease, and resources to improve before ambulating.
Conclusions
Nurses who claimed responsibility for ambulating patients within their domain of practice described actions that promoted patient independent function and were more likely to get patient s up to ambulate.
doi:10.1016/j.ijnurstu.2013.02.007
PMCID: PMC3711943  PMID: 23465958
Hospital; Nursing care; Ambulating; Older patients; Grounded dimensional analysis
19.  Effect of reducing ambulance response times on deaths from out of hospital cardiac arrest: cohort study 
BMJ : British Medical Journal  2001;322(7299):1385-1388.
Objectives
To determine the association between ambulance response time and survival from out of hospital cardiopulmonary arrest and to estimate the effect of reducing response times.
Design
Cohort study.
Setting
Scottish Ambulance Service.
Subjects
All out of hospital cardiopulmonary arrests due to cardiac disease attended by the Scottish Ambulance Service during May 1991 to March 1998.
Main outcome measures
Survival rate to hospital discharge and potential improvement from reducing response times.
Results
Of 13 822 arrests not witnessed by ambulance crews but attended by them within 15 minutes, complete data were available for 10 554 (76%). Of these patients, 653 (6%) survived to hospital discharge. After other significant covariates were adjusted for, shorter response time was significantly associated with increased probability of receiving defibrillation and survival to discharge among those defibrillated. Reducing the 90th centile for response time to 8 minutes increased the predicted survival to 8%, and reducing it to 5 minutes increased survival to 10-11% (depending on the model used).
Conclusions
Reducing ambulance response times to 5 minutes could almost double the survival rate for cardiac arrests not witnessed by ambulance crews.
What is already known on this topicThree quarters of all deaths from myocardial infarction occur after cardiac arrest in the communitySurvival after out of hospital arrest is much lower in the United Kingdom than the United StatesWhat this study addsAmbulance response times are independently associated with defibrillation and survivalDecreasing the target for response to 90% of calls from 14 minutes to 8 minutes would increase survival from 6% to 8%A response time of 5 minutes would increase survival to 10-11%
PMCID: PMC32251  PMID: 11397740
20.  Early stroke care in Italy—a steep way ahead: an observational study 
Emergency Medicine Journal : EMJ  2006;23(8):608-611.
Objectives
To measure the performance of selected Italian emergency medical system (EMS) dispatch centres managing calls for patients suffering from stroke. Data on outcome and on early treatment in the ED were collected.
Methods
Prospective data collection for a trimester from interventions for a suspected stroke in 13 EMS dispatch centres over five Italian regions.
Results
Altogether, 1041 calls for a suspected stroke were analysed. Mean intervals of the sequential phases were 2.3±2 minutes between call and ambulance dispatch, 8.4±5.5 minutes to reach the patient, 14.5±8.5 minutes on the scene, and 40.2±16.2 minutes between call and arrival at the ED. Interventions were performed in 56% of cases by a basic life support (BLS) crew, advanced life support (ALS) crews intervened in 28% of cases, and a combination of ALS and BLS in the remaining 16%. Mean diagnostic interval was 99±85 minutes between emergency system call and the first CT scan. This was performed 71±27 minutes after ED admission. Only 1.6% were admitted to a stroke unit. One month outcome according to GCS was good recovery in 32%, moderate disability in 28%, severe disability in 14%, and death in 25% of the patients.
Conclusions
Mean times show a rapid response of the selected EMS dispatch centres to calls for a suspected stroke. Nevertheless, mean times of the ED phase are still unacceptable according to international guidelines such as Brain Attack Coalition and American Stroke Association guidelines. Efforts should be spent to reduce the time between the arrival and the CT scan and more patients should be admitted to a stroke unit.
doi:10.1136/emj.2005.032219
PMCID: PMC2564161  PMID: 16858091
emergency medicine; prehospital; stroke
21.  Study of early warning of accident and emergency departments by ambulance services. 
OBJECTIVE: To determine the warning time given to accident and emergency (A&E) departments by the ambulance service before arrival of a critically ill or injured patient. To determine if this could be increased by ambulance personnel alerting within five minutes of arrival at scene. METHODS: Use of computerised ambulance control room data to find key times in process of attending a critically ill or injured patient. Modelling was undertaken with a scenario of the first responder alerting the A&E department five minutes after arrival on scene. RESULTS: The average alert warning time was 7 min (range 1-15 min). Mean time on scene was 22 min (range 4-59 min). In trauma patients alone, the average alert time was 7 min, range 2-15 min, with an average on scene time of 23 min, range 4-53 min. There was a potential earlier alert time averaging 25 min (SD 18.6, range 2-59 min) if the alert call was made five minutes after arrival on scene. CONCLUSIONS: A&E departments could be alerted much earlier by the ambulance service. This would allow staff to be assembled and preparations to be made. Disadvantages may be an increased "alert rate" and wastage of staff time while waiting the ambulance arrival.
PMCID: PMC1347052  PMID: 10505913
22.  An Observational Study of Patient Characteristics Associated with the Mode of Admission to Acute Stroke Services in North East, England 
PLoS ONE  2013;8(10):e76997.
Objective
Effective provision of urgent stroke care relies upon admission to hospital by emergency ambulance and may involve pre-hospital redirection. The proportion and characteristics of patients who do not arrive by emergency ambulance and their impact on service efficiency is unclear. To assist in the planning of regional stroke services we examined the volume, characteristics and prognosis of patients according to the mode of presentation to local services.
Study design and setting
A prospective regional database of consecutive acute stroke admissions was conducted in North East, England between 01/09/10-30/09/11. Case ascertainment and transport mode were checked against hospital coding and ambulance dispatch databases.
Results
Twelve acute stroke units contributed data for a mean of 10.7 months. 2792/3131 (89%) patients received a diagnosis of stroke within 24 hours of admission: 2002 arrivals by emergency ambulance; 538 by private transport or non-emergency ambulance; 252 unknown mode. Emergency ambulance patients were older (76 vs 69 years), more likely to be from institutional care (10% vs 1%) and experiencing total anterior circulation symptoms (27% vs 6%). Thrombolysis treatment was commoner following emergency admission (11% vs 4%). However patients attending without emergency ambulance had lower inpatient mortality (2% vs 18%), a lower rate of institutionalisation (1% vs 6%) and less need for daily carers (7% vs 16%). 149/155 (96%) of highly dependent patients were admitted by emergency ambulance, but none received thrombolysis.
Conclusion
Presentations of new stroke without emergency ambulance involvement were not unusual but were associated with a better outcome due to younger age, milder neurological impairment and lower levels of pre-stroke dependency. Most patients with a high level of pre-stroke dependency arrived by emergency ambulance but did not receive thrombolysis. It is important to be aware of easily identifiable demographic groups that differ in their potential to gain from different service configurations.
doi:10.1371/journal.pone.0076997
PMCID: PMC3792886  PMID: 24116195
23.  Clinical evaluation of the Emergency Medical Services (EMS) ambulance dispatch-based syndromic surveillance system, New York City 
Since 1998, the New York City Department of Health has used New York City Emergency Medical Services (EMS) ambulance dispatch data to monitor for a communitywide rise in influenzalike illness (ILI) as an early detection system for bioterrorism. A clinical validation study was conducted during peak influenza season at six New York City emergency deparments (EDs) to compare patients with ILI brought in by ambulance with other patients to examine potential biases associated with ambulance dispatch-based surveillance. We also examined the utility of 4 EMS call types (selected from 52) for case detection of ILI. Clinical ILI was defined as fever (temperature higher than 100°F) on history or exam, along with either cough or sore throat. Of the 2,294 ED visits reviewed, 522 patients (23%) met the case definition for ILI, 64 (12%) of whom arrived by ambulance. Patients with ILI brought in by ambulance were older, complained of more severe symptoms, and were more likely to undergo diagnostic testing, be diagnosed with pneumonia, and be admitted to the hospital than patients who arrived by other means. The median duration of symptoms prior to presenting to the ED, however, was the same for both groups (48 hours). The selected call types had a sensitivity of 58% for clinical ILI, and a predictive value positive of 22%. Individuals with symptoms consistent with the prodrome of inhalational anthrax were likely to utilize the EMS system and usually did so early in the course of illness. While EMS-based surveillance is more sensitive for severe illness and for illness affecting older individuals, there is not necessarily a loss of timeliness associated with EMS-based (versus ED-based) surveillance.
doi:10.1007/PL00022315
PMCID: PMC3456558  PMID: 12791779
24.  Primary Angioplasty for the Treatment of Acute ST-Segment Elevated Myocardial Infarction 
Executive Summary
One of the longest running debates in cardiology is about the best reperfusion therapy for patients with evolving acute myocardial infarction (MI). Percutaneous transluminal coronary angioplasty (ANGIOPLASTY) is a surgical treatment to reopen a blocked coronary artery to restore blood flow. It is a type of percutaneous (through-the-skin) coronary intervention (PCI) also known as balloon angioplasty. When performed on patients with acute myocardial infarction, it is called primary angioplasty. Primary angioplasty is an alternative to thrombolysis, clot-dissolving drug therapy, for patients with acute MI associated with ST-segment elevation (STEMI), a change recorded with an electrocardiogram (ECG) during chest pain.
This review of the clinical benefits and policy implications of primary angioplasty was requested by the Ontario Health Technology Advisory Committee and prompted by the recent publication of a randomized controlled trial (RCT) in the New England Journal of Medicine (1) that compared referred primary angioplasty with on-site thrombolysis. The Medical Advisory Secretariat reviewed the literature comparing primary angioplasty with thrombolysis and other therapies (pre-hospital thrombolysis and facilitated angioplasty, the latter approach consisting of thrombolysis followed by primary angioplasty irrespective of response to thrombolysis) for acute STEMI.
There have been many RCTs and meta-analyses of these RCTs comparing primary angioplasty with thrombolysis and these were the subject of this analysis. Results showed a statistically significant reduction in mortality, reinfarction, and stroke for patients receiving primary angioplasty. Although the individual trials did not show significant improvements in mortality alone, they did show it for the outcomes of nonfatal reinfarction and stroke, and for an end point combining mortality, reinfarction, and stroke. However, researchers have raised concerns about these studies.
A main concern with the large RCTs is that they lack consistency in methods. Furthermore, there is some question as to their generalizability to practice in Ontario. Across the RCTs, there were differences in the type of thrombolytic drug, the use of stenting versus balloon-only angioplasty, and the use of the newer antiplatelet glycoprotein IIb/IIIa. The largest trial did not offer routine follow-up angioplasty for patients receiving thrombolysis, which is the practice in Ontario, and the meta-analysis included trials with streptokinase, an agent seldom used in hospitals in Ontario. Thus, the true magnitude of mortality benefit can only be surmised from head-to-head comparisons of current standard therapies for primary angioplasty and for thrombolysis.
By taking a more restrictive sample of the available studies, the Medical Advisory Secretariat conducted a review that was more consistent with patterns of practice in Ontario and selected trials that used accelerated alteplase as the thrombolytic agent.
Results from this meta-analysis suggest that the rates for primary angioplasty are significantly better for mortality, reinfarction, and stroke, in the short term (30 days), and for mortality, reinfarction, and the combined end point at 6 months. When primary angioplasty was compared with in-hospital thrombolysis, results showed a significant reduction in adverse event rates associated with primary angioplasty. However, 1 large RCT of pre-hospital thrombolysis (i.e., thrombolysis given by paramedics before arriving at the hospital) compared with primary angioplasty documented that pre-hospital thrombolysis is an equivalent intervention to primary thrombolysis in terms of survival. Furthermore, a meta-analysis of studies that compared pre-hospital thrombolysis with in-hospital thrombolysis showed a reduction in all hospital mortality rates in favour of pre-hospital thrombolysis, supporting the findings of the pre-hospital thrombolysis study. (2)
Clinical trials to date have reported that hospital stay is often reduced for patients who receive primary angioplasty compared with thrombolysis. Using a cost-analysis performed alongside the only study from Ontario, the Medical Advisory Secretariat concluded that there might be savings associated with primary angioplasty. These savings may partly offset the investment the provincial government would have to make to increase access to this technology. These savings should also be shown outside of a clinical trial protocol if the overall efficiencies of primary angioplasty are to be verified.
Based on this health technology policy analysis, the Medical Advisory Secretariat concludes that primary angioplasty has advantages with respect to mortality and combined end points compared with in-hospital thrombolysis (Level 1 evidence). However, pre-hospital thrombolysis improves survival compared with in-hospital thrombolysis (Level 1 evidence) and is equivalent to primary angioplasty (Level 1 evidence).
Results from the literature review raise concerns about the loss of therapeutic advantage due to treatment delays, time lapse from symptom onset to revascularization, time-of-day variations, the hospital volume of procedures, and the ability of hospitals to achieve in practice what RCTs have shown.
Furthermore, questions relevant to applying primary angioplasty widely, involve the diagnosis by paramedics, ambulance diversion protocols, paramedic training, and inter-hospital transfer protocols. These logistical considerations need to be addressed to realise the potential to improve patient outcomes. In its analysis, the Medical Advisory Secretariat concludes that it is unrealistic to reorganise the emergency medical services across Ontario to fully implement a primary angioplasty program.
Finally, it is important to evaluate the potential of this technology in the context of Ontario’s health system. This includes urban and rural considerations, the ability to expand access to primary angioplasty and to minimize symptom-to-assessment time through a diverse strategy including public awareness. Therefore, a measured, evaluative approach to adopting this technology is warranted.
Furthermore, the alternative approach to pre-hospital or early thrombolysis, especially within 120 minutes from onset of symptoms, should be considered when developing the approach to improving outcomes for acute MI. This could include efforts to decrease the symptom-to-thrombolysis time through strategies such as a concerted public education program to expedite presentation to emergency rooms after onset of symptoms, a pre-hospital ECG and thrombolysis checklist in ambulances to reduce door-to-needle time on arrival at emergency rooms, and, especially in remote areas, access to pre-hospital thrombolysis.
The Medical Advisory Secretariat therefore recommends that this analysis of primary angioplasty be viewed in the overall context of all interventions for the management of acute MI and, in particular, of improving access to primary angioplasty and maximising the use of early thrombolysis.
Outcomes for patients with acute MI can be improved if efforts are made to optimise the interval from symptom onset to thrombolysis or angioplasty. This will require concerted efforts, including public awareness through education to reduce the symptom-to-emergency room time, and maximising efficiencies in door-to-intervention times for primary angioplasty and for early thrombolysis.
Primary angioplasty and early thrombolysis cannot be considered in isolation from one another. For example, patients who have persistent STEMI 90 minutes after receiving thrombolysis should be considered for angioplasty (“rescue angioplasty”). Furthermore, for patients with acute MI who are in cardiac shock, primary angioplasty is considered the preferred intervention. The concomitant use of primary angioplasty and thrombolysis (“facilitated angioplasty”) is considered experimental and has no place in routine management of acute MI at this time. In remote parts of the province, consideration should be given to introducing pre-hospital thrombolysis as the preferred intervention through upgrading a select number of paramedics to advanced care status.
PMCID: PMC3387753  PMID: 23074449
25.  Mobile Phones, in Combination with a Computer Locator System, Improve the Response Times of Emergency Medical Services in Central London 
INTRODUCTION
The aim of this study was to determine whether mobile phones and mobile phone locating devices are associated with improved ambulance response times in central London.
PATIENTS AND METHODS
All calls from the London Ambulance Service database since 1999 were analysed. In addition, 100 consecutive patients completed a questionnaire on mobile phone use whilst attending the St Thomas's Hospital Emergency Department in central London.
RESULTS
Mobile phone use for emergencies in central London has increased from 4007 (5% of total) calls in January 1999 to 21,585 (29%) in August 2004. Ambulance response times for mobile phone calls were reduced after the introduction of the mobile phone locating system (mean 469 s versus 444 s; P = 0.0195). The proportion of mobile phone calls made from mobile phones for life-threatening emergencies was higher after injury than for medical emergencies (41% versus 16%, P = 0.0063). Of patients transported to the accident and emergency department by ambulance, 44% contacted the ambulance service by mobile phone. Three-quarters of calls made from outside the home or work-place were by mobile phone and 72% of patients indicated that it would have taken longer to contact the emergency services if they had not used a mobile.
CONCLUSIONS
Since the introduction of the mobile phone locating system, there has been an improvement in ambulance response times. Mobile locating systems in urban areas across the UK may lead to faster response times and, potentially, improved patient outcomes.
doi:10.1308/003588408X242079
PMCID: PMC2443303  PMID: 18325208
Mobile; Phone; Emergency; Locator; Response; Trauma

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