***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: STUDY OBJECTIVE To develop an operational definition and a parsimonious list of postulated determinants for urban emergency department ( ED ) overcrowding .  METHODS A panel was formed from clinical and administrative experts in pre-hospital , ED and hospital domains . Key studies and reports were review ed in advance by panel members , an experienced health services research er facilitated the panel 's discussion s , and a formal content analysis of audiotaped recordings was conducted . RESULTS The panel considered community , patient , ED and hospital determinants of overcrowding . Of 46 factors postulated in the literature , 21 were not retained by the experts as potentially important determinants of overcrowding . Factors not retained included access to primary care services and seasonal influenza outbreaks . Key determinants retained included admitted patients awaiting beds and patient characteristics .  Ambulance diversion was considered to be an appropriate operational definition and proxy measure of ED overcrowding . CONCLUSION These results help to clarify the conceptual framework around ED overcrowding , and may provide a guide for future research . The relative importance of the determinants must be assessed by prospect i ve studies Objectives : To determine the impact of establishing walk-in centres alongside emergency departments ( EDs ) on attendance rates , visit duration , process , costs and outcome of care . Methods : Eight hospitals with co-located EDs and walk-in centres were compared with eight matched EDs without walk-in centres .  Site visits were conducted . Routine data about attendance numbers and use of re sources were analysed . A r and om sample of records of patients attending before and after the opening of walk-in centres  was also assessed . Patients who had not been admitted to hospital were sent a postal question naire . Results : At most sites , the walk-in centres did not have a distinct identity and there were few differences in the way services were provided compared with control sites . Overall , there was no evidence of an increase in attendance at sites with walk-in centres , but considerable variability across sites was found . The proportion of patients managed within the 4 h National Health Service target improved at sites both with and without walk-in centres . There was no evidence of any difference in reconsultation rates , costs of care or patient outcomes at sites with or without walk-in centres . Conclusions : Most hospitals in this study implemented the walk-in centre concept to a very limited extent . Consequently , there was no evidence of any effect on attendance rates , process , costs or outcome of care Background : A&E departments are key points of contact for many people with mental health problems . Various models of care have been developed in A&E departments for delivering mental health services , but few have been assessed for effectiveness . The present study aim ed to assess the impact of a dedicated A&E psychiatric nurse service on several outcomes relevant to patients and clinicians . Methods : A crossover design was used to introduce a  dedicated psychiatric nurse service ( comprising four experienced community psychiatric nurses ) into two busy UK A&E departments . St and ardised assessment s were completed for each patient , and a r and om sample of these independently assessed for quality . Data were also collected on the number of patients assessed , psychiatric nurse time employed , waiting times , onward referrals , repeat attendances , patient satisfaction , and staff views . Results : A&E staff referred about a third of patients judged to have mental health problems to the psychiatric nurse service ; approximately half of those assessed had a psychiatric history . On average , assessment s took 60 min and over 90 % of the formulated management plans were judged appropriate by independent assessors . The psychiatric nurse intervention had little impact on waiting times or satisfaction levels for mental health patients , although there was evidence of a change in onward referral patterns . Comment : Psychiatric nurse assessment services have been introduced in many A&E departments , although the evidence base for the effectiveness of this development is not well established . This study presents evidence that psychiatric nurses can provide an accurate assessment and referral service with advantages for patient care Patient safety and medical errors in ambulatory primary care are receiving increasing attention from policy makers , accreditation bodies and research ers , as well as by practising family physicians and their patients . While a great deal of progress has been made in underst and ing errors in hospital setting s , it is important to recognise that ambulatory setting s pose a very large and different set of challenges and that the types of hazards that exist and the strategies required to reduce them are very different . What is needed is a logical theoretical model for underst and ing the causes of errors in primary care , the role of healthcare systems in contributing to errors , the propagation of errors through complex systems and , importantly , for underst and ing ambulatory primary care in the context of the larger healthcare system . The authors have developed such a model using a formal ' systems engineering ' approach borrowed from the management sciences and engineering . This approach has not previously been formally described in the medical literature .This paper outlines the formal systems approach , presents our visual model of the system , and describes some experiences with and potential applications of the model for monitoring and improving safety . Applications include providing a framework to help focus research efforts , creation of new ( visual ) error reporting and taxonomy systems , furnishing a common and unambiguous vision for the healthcare team , and facilitating retrospective and prospect i ve analyses of errors and adverse events . It is aim ed at system re design for safety improvement through a computer-based patient-centred safety enhancement and monitoring instrument ( SEMI-P ) . This model can be integrated with electronic medical records ( EMRs ) Objectives : To describe an experience of emergency department ( ED ) overcrowding and ambulance bypass . Methods : A prospect i ve observational study at Royal Perth Hospital , a major teaching hospital . Episodes of ambulance bypass and their characteristics were recorded . Results : From 1 July 1999 to 30 June 2001 , there were 141 episodes of ambulance bypass ( mean duration 187 min , range 35–995 ) . Monday was the most common day with 39 ( 28 % ) episodes . Entry block alone was the most common reason bypass was activated ( n=38 , 30.4 % ) . The mean number of patients in ED  at these times was 40 ( occupancy 174 % ) , including nine in the corridor , seven awaiting admission , and 14 waiting to be seen . Episodes attributable to entry block were typically preceded by a presentation rate of ⩾10 patients per hour for ⩾2 hours ( OR 6.2 , 95 % CI 4.3 to 8.5 ) . Mid-afternoon to early evening was the most common time for activation  . Ambulance bypass  is increasing in frequency and duration . Conclusions : Entry overload result ing in entry block results from overwhelming numbers of patients presenting to the ED in a short space of time . Entry block impairs access to emergency care . Unless something is done in the near future , the general public may no longer be able to rely on EDs for quality and timely emergency care . A “ whole of system ” approach is necessary to tackle the problem OBJECTIVE Some low-acuity emergency department ( ED ) presentations are considered convenience visits and potentially avoidable with improved access to primary care services . This study assessed the frequency and determinants of patients ' efforts to access alternative care before ED presentation . METHODS Patients aged 17 years and older were r and omly selected from 2 urban ED sites in Edmonton .  Survey data were collected on use and characteristics of alternative care before the ED visit . Information was also collected on patient demographics and factors influencing their perception of whether the ED was the best care option . RESULTS Of the 1,389 patients approached , 905 ( 65 % ) completed the survey and data from 894 participants were analyzed . Sixty-one percent reported that they sought alternative care  before visiting the ED . Eighty-nine of the patients who attempted alternative access before the ED visit felt that the ED was their best care option . Results of the multivariate logistic regression analysis showed that injury presentation , living arrangements , smoking status and whether or not patients had a family practitioner were predictors for seeking alternative care before visiting the ED . CONCLUSION Most ambulatory patients attempt to look for other sources of care before presenting to the ED . Despite this attempted access to alternative care , while patients wait for ED care , they perceive that the ED is their best care option at that point in time BACKGROUND ED overcrowding is fast becoming a national crisis although no definition exists . The purpose of this study is to develop and pilot a sampling form that accurately reflects the concept of ED Overcrowding . MATERIAL / METHODS A 26- question site-sampling form was design ed based on input from academic physicians at 11 medical schools nationwide . The study was conducted at an inner city Academic medical center . Site-samplings were conducted at 20 times over a one-week period by an independent observer . These times ranged from very slow to severely overcrowded . Information was obtained by counting patients in the waiting room , ED rooms , ED halls and registration /triage , ancillary services , the charge nurse , and the attending physicians . The charge nurse , and ED physicians rated the degree of overcrowding and the ED physician rated the feeling of being rushed . A ' combined outcome variable ' was created which consisted of the average responses of nurses and physician 's opinion of ED overcrowding and physician 's feeling of being rushed . All other data was compared to this outcome variable . RESULTS Seven questions were significantly correlated with the combined outcome variable . These were the number of people in the waiting room , patients awaiting triage , patients awaiting registration , full patient rooms , hallway patient , patients awaiting beds , and total registered patients . According to this scale our ED was overcrowded 20 % of the time . CONCLUSIONS This analysis clarifies the definition of overcrowding , helps indicate the variance among responses to overcrowding questions , and provides the foundation for prospect i ve analysis of overcrowding in multiple EDs 
    Output:
    
RESULTS There is an established international literature on ED crowding .
It suggests consistently that crowding has significant negative consequences .
CONCLUSIONS While current evidence is poor , this does not justify maintaining current practice which risks lives .