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The epidemiology of adults with severe sepsis and septic shock in Scottish emergency departments
  1. Alasdair Gray1,
  2. Kirsty Ward2,
  3. Fiona Lees2,
  4. Colin Dewar3,
  5. Sarah Dickie4,
  6. Crawford McGuffie5,
  7. On behalf of the STAG steering committee
  1. 1Emergency Department, Royal Infirmary of Edinburgh, Edinburgh, UK
  2. 2Scottish Trauma Audit Group, NHS National Services Scotland, Paisley, UK
  3. 3Emergency Department, Victoria Hospital, Kirkcaldy, UK
  4. 4Emergency Department, Crosshouse Hospital, Kilmarnock, UK
  5. 5Emergency Department, Crosshouse Hospital, Kilmarnock, UK, and, Chairman of the Scottish Trauma Audit Group
  1. Correspondence to Dr Crawford McGuffie, Consultant in Emergency Medicine, Associate Medical Director, Ayrshire and Arran Health Board, Chairman, Scottish Trauma Audit Group, Emergency Department, Crosshouse Hospital, Kilmarnock KA2 OBE, UK; crawford.mcguffie{at}aaaht.scot.nhs.uk

Abstract

Background The Surviving Sepsis Campaign (SSC) promotes a bundle approach to the care of septic patients to improve outcome. Some have questioned the capability of delivering the bundle in emergency departments (EDs). The authors report the epidemiology and 6 h bundle compliance of patients with severe sepsis/septic shock presenting to Scottish EDs.

Methods Analysis of the previously reported Scottish Trauma Audit Group sepsis database was performed including 20 mainland Scottish EDs. A total of 308 910 attendances were screened (between 2 March and 31 May 2009), and 5285 of 27 046 patients were identified after case note review and included on the database. This analysis includes patients who had severe sepsis/septic shock before leaving the ED. Epidemiological, severity of illness criteria, and ED management data were analysed.

Results 626 patients (median age 73; M/F ratio 1:1; 637 presentations) met entrance criteria. The median number of cases per site was 16 (range 3–103). 561 (88.1%) patients arrived by ambulance. The most common source of infection was the respiratory tract (n=411, 64.5%) The most common physiological derangements were heart rate (n=523, 82.1%), respiratory rate (n=452, 71%) and white cell count (n=432, 67.8%). The median hospital stay was 9 days (IQR 4–17 days). 201 (31.6%) patients were admitted to critical care within 2 days, 130 (20.4%) directly from the ED. 180 patients (28.3%) died. There was poor compliance with all aspect of the SSC resuscitation bundle.

Conclusions Sepsis presentations are of variable frequency but have typical epidemiology and clinical outcomes. SSC bundle resuscitation uptake is poor in Scottish EDs.

  • Audit
  • care systems
  • clinical care
  • emergency department
  • infection
  • diagnosis
  • thromboembolic disease

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Background

Sepsis is one of the leading causes of hospital admission and death worldwide.1 ,2 Despite improving outcomes in healthcare, mortality related to sepsis remains high.3 ,4 The Surviving Sepsis Campaign (SSC) promotes a bundle approach to the care of patients with sepsis in an attempt to reduce mortality.5 Many professional organisations including the College of Emergency Medicine (CEM) have adopted this systematic approach for the early care of patients with sepsis or septic shock by making it a specialty quality standard.6 Some have questioned the evidence supporting the components of this bundle, its appropriateness for all patients, and the difficulty in safely delivering it in ‘real life’.7 ,8 Three large pragmatic international trials are currently investigating whether all or some of the components of the sepsis bundle can be delivered and improve outcome.9–11 Given the continued international interest in sepsis and the lack of epidemiological sepsis data, the Scottish Trauma Audit Group (STAG) decided to investigate the prevalence of sepsis in patients admitted to Scottish hospitals and to describe the epidemiology and early care received by this patient group. This report describes the characteristics, emergency department (ED) care and outcome of the patients presenting with severe sepsis or septic shock in Scottish EDs contributing to this national audit.

Methods

An analysis of the previously reported STAG sepsis database was performed.12 Twenty of the 25 mainland district general and teaching hospital EDs participated in the audit (online appendix 1).

The data collection period had both a prospective and retrospective phase. Patients who attended hospital between 2 March and 31 May 2009 were identified prospectively from ED records. This process identified 308 910 initial patient attendances.

Hospital information systems were then interrogated to ascertain whether the patient had an inpatient stay of at least 2 days. Patients who died within the first 2 days, and therefore may have been omitted from data collection, were identified retrospectively by the Local Audit Coordinators using General Register Office Scotland records, and eligible patients were included for analysis. Patients who had an obviously non-infective reason for attendance, such as acute cardiac ischaemia, trauma or stroke, and all patients aged <17 years were excluded.

This process identified 27 046 ED patients who required case note review to determine the presence of the following ‘sepsis’ criteria (figure 1): (1) suspicion or confirmation of infection within 2 days of ED presentation; (2) presence of two of the following physiological criteria: temperature >38.3°C or <36°C; heart rate >90 beats/min; respiratory rate >20/min; white cell count >12 000/μl or <4000/μl or >10% immature forms; acutely altered mental status; systolic blood pressure <90 mm Hg; and blood glucose >7.7 mmol/l (in the absence of diabetes).5 Data were then collected retrospectively on a variety of demographic, physiological, process and outcome variables using a standardised proforma (online appendix 3). All patients were followed to discharge or death.

Figure 1

Patient screening and inclusion criteria.

A total of 5285 ED patients fulfilled the entry criteria. The difficulties encountered in obtaining and extracting data from case notes (27 046 sets of case notes were reviewed) were such that a pragmatic decision was taken to stop data collection in July 2010. This meant 1395 (26%) patients did not have full data collection and so were not available for analysis. Of the 20 participating hospitals, eight (40%) collected a full dataset for all patients who met the inclusion criteria. Completion at the other hospitals ranged between 21% and 95%.

This analysis only includes patients who fulfilled criteria for severe sepsis or septic shock before leaving the ED. Epidemiological, physiological and severity of illness criteria and early ED management data were collated, analysed and presented using mainly descriptive analysis (proportion, median, IQR and range). The Z test was used to calculate the difference between two proportions, and differences between medians were calculated using the Mann–Whitney U test. All differences are reported along with their associated 95% CIs and p value.

All data were anonymised before submission to the STAG central team at ISD (Information Services Division). The Caldicott guardian of each participating health board was informed of the audit and the processes involved. ISD, as part of NHS National Services Scotland, uses strict rules around information governance and the protection of information. All health information is held securely and managed according to data protection regulations.

Results

During the study period, there were 308 910 attendances at the 20 participating hospitals. A total of 5285 (1.7%) of these patients developed criteria for diagnosis of sepsis within 2 days of presentation. The prevalence rate between hospitals ranged from 0.7% to 3.1% of attendances. Data were available for analysis in 3890 (73.6%) patients with sepsis. Of these, 626 had 637 (16.4%) presentations with signs and symptoms of severe sepsis or septic shock before discharge from the ED. The median number of ED cases per site was 16 (range 3–103).

Patient characteristics

The median age of patients was 73 years (range 17–98) and the male to female ratio was 1:1.

Mode and time of arrival

The majority of patients arrived by ambulance (n=561, 88.1%). Attendance was ‘out of hours’ (between 20:00 and 07:59 or at the weekend) for 311 (49%) patients. A consultant was more likely to be documented to be in attendance ‘in hours’ than ‘out of hours’ (16.3% vs 3.6% (difference 12.7%, 95% CI 8.1% to 17.3%, p<0.05)).

Sepsis criteria, infection source and sepsis bundle compliance

The most common suspected source of infection was the respiratory tract (n=411, 64.5%) (table 1. The most common physiological derangements at the time of first record of meeting sepsis criteria were heart rate (n=523, 82.1%), respiratory rate (n=452, 71%) and white cell count (n=432, 67.8%) (figure 2). The number of identified abnormal Systemic Inflammatory Response Syndrome (SIRS) criteria is detailed in table 2. Table 3 gives the compliance with the CEM sepsis guidelines6 and the initial 6 h bundle of the SSC.5

Table 1

Presumed source of infection

Figure 2

Type of physiological abnormality at time of patient inclusion in audit (first signs of sepsis).

Table 2

Number of abnormal physiological criteria* at time of patient inclusion in audit (first signs of sepsis)

Table 3

Sepsis resuscitation bundle compliance

Admission and outcome

The median length of stay was 9 days (IQR 4–17 days). Two hundred and one (31.6%) patients were admitted to critical care within 2 days of attendance, 130 (20.4%) directly from the ED. A further nine patients were admitted to critical care within 6 h of developing signs of severe sepsis in the ED, but were admitted from an inpatient area. Patients were more likely to go to critical care directly from ED if a consultant was documented to be in attendance (44.4% vs 17.7% (difference 26.7%, 95% CI 14.0% to 39.4%, p<0.05)). Patients were more likely to go to critical care directly from ED out of hours than in hours; however this difference was not significant (22.5% vs 18.4% (difference 4.1%, 95% CI −2.2% to 10.4%, p=0.20)). Patients who were admitted to critical care were younger than those who were not (67 years (IQR 55–76) vs 75 years (IQR 65–83) (difference 8 years, 95% CI 4 to 12, p<0.05)).

A total of 180 patients (28.3%) died during the index hospitalisation, 10 within the ED and 59 (9.3%) within 1 day of attendance. Men were more likely to die than women, although not significantly (30.3% vs 26.3% (difference 4%, 95% CI −3.0% to 11%, p=0.27)). Patients who died were older than those who did not (77 years (IQR 68–85) vs 71 (IQR 60–80) (difference 6 years, 95% CI 3 to 9, p<0.05)). Patients who were admitted to critical care were more likely to die than those who were not, but not significantly (30.8% vs 27.1% (difference 3.7%, 95 CI −3.9% to 11.3%, p=0.33)).

Discussion

This is the first study to describe the characteristics and ED interventions in severe sepsis and septic shock across Scotland. This is in the context of recent international and UK-based initiatives to improve standards of care in severe sepsis in the ED.5 ,6 The CEM published standards for the management of severe sepsis and septic shock in May 2009. Recent modifications to the original CEM standards have resulted in the ‘sepsis six’ standards to be completed within 1 h of ED presentation.13

The median age of patients in our study was 73 years, with a distribution skewed towards patients 60 years or older. This is consistent with previous studies of ED patients with sepsis.14 During the index hospitalisation, 28.3% of patients died. This is similar to the mortality in the early goal-directed therapy group (30.5%) in the seminal study by Rivers et al 15 and the SOAP study in Europe (36%).3 Previously published UK data have suggested a mortality of 40% for patients admitted with severe sepsis to intensive care (National Audit and Research Centre) and 43% for patients presenting to the ED.4 Despite the lower than expected mortality, compliance with the individual components of the 6 h sepsis bundle was found to be extremely low.

The SSC recommended that intravenous antibiotic therapy be started as early as possible and within the first hour of recognition of septic shock and severe sepsis. There is increasing evidence that antibiotic administration in the first hour is one of the principal determinants of survival in severe sepsis.16 We found antibiotic administration in the first 3 h of the identification of sepsis in Scottish EDs to be comparable to previously reported performance internationally (66% in 3 h vs 67.9% within 6 h of presentation in the SSC international performance improvement initiative17). The CEM recommends that 50% of patients receive antibiotics within 1 h; our performance was found to be lower at 32.3%.12

The CEM recommended that 95% of cases should have blood cultures and documented serum lactate measurement. Performance in Scottish EDs was found to be lower than the recommended standards with regard to both investigations: 29% of patients had blood cultures (79% before antibiotics) and 55% had a lactate measurement documented within 6 h of development of sepsis.

Early fluid resuscitation, with either colloids or crystalloids, is recommended as part of the SSC guidelines (grade 1B). The CEM sepsis standards require documented evidence that the first intravenous crystalloid bolus (up to 20 ml/kg) was given in 75% of cases within 1 h and in 100% of cases before leaving the ED. The fluid resuscitation component of severe sepsis management was found to be below the CEM standards in Scottish EDs. Only 48% of patients with a systolic blood pressure 90 mm Hg, 43% with lactate >4 mmol/l, and 51% with both received documented fluid resuscitation within 6 h. Despite the problems inherent in the early recognition of severe sepsis, these figures are surprisingly low, particularly when compared with published figures from elsewhere in the UK. Eighty-four per cent of patients received fluid resuscitation in a study based in three EDs in the West Midlands.13 However, given the number of patients with status regarding intravenous fluid resuscitation recorded as unknown (23–36%), this particular result has to be interpreted with caution. Vasopressor use in non-responders was also found to be low (35–42%), which is consistent with previously reported reluctance among Scottish emergency medicine specialist registrars to initiate treatment with norepinephrine and dobutamine.18

Early recognition of severe sepsis and septic shock is clearly pivotal to the initiation of time-dependent interventions. The difficulty inherent in differentiating sepsis from other acute presentations to ED is illustrated by the most common physiological derangements highlighted in this study, namely heart rate and respiratory rate, with temperature being deranged in <50% of cases. Moreover, systolic blood pressure was noted to be deranged in only 26% of cases at the point of inclusion in the study. Clinical reliance on the development of hypotension before consideration of potential sepsis may delay diagnosis and treatment. The high rate of attendance by ambulance (88.1%) would indicate that there might be a role for prehospital screening similar to models currently practised in other time-critical conditions (ST elevation, myocardial infarction or acute stroke). Currently, up to 56% of critically ill patients arrive at hospital unannounced.19 A prehospital sepsis screening tool has been advocated and would be expected to increase the perceived acuity and subsequent need for senior ED involvement.20 Although 5285 patients fulfilled the entry criteria, it was only possible to record full data for 3890 (74%) of the cases. This was due to a combination of time constraints and difficulties encountered in obtaining data from case notes. There was considerable variation in the completeness of data collection between sites, and this may be a source of potential bias. Although we cannot accurately quote the total number of patients with severe sepsis in the 3-month period of the study, we are able to report on a large sample (637 attendances) of patients and the completion of CEM and SSC guidelines in this group. The findings are based on patients attending Scottish EDs and are specific to the Scottish healthcare system, but many of the factors that constrain performance against time-dependent interventions have been shown to be consistent across emergency care systems in the developed world.

Despite the relatively low mortality compared with other studies, there is evidence that compliance with both the CEM sepsis and SSC guidelines remains a challenge across Scottish EDs. Further work is needed on the factors that result in delayed recognition of severe sepsis and possible tools to improve early diagnosis and initiation of currently recommended time-dependent treatments. It is hoped that the currently running international trials of early goal-directed therapy in severe sepsis will provide greater clarity as to whether all of the currently recommended components of this therapy are indeed time dependent and the relevant contributions of the component parts to reductions in mortality from severe sepsis.9–11 The impact of senior ED clinicians, overcrowding and prehospital screening on time to intervention and clinical outcome are further areas that require research.

References

Footnotes

  • Members of the STAG steering committee are listed in online appendix 1.

  • Funding Scottish Trauma Audit Group (STAG) is part of the Quality Improvement Programme at ISD (Information Services Division), a division of NHS National Services Scotland. STAG was set up in 1991 to audit the management of seriously injured patients in Scotland. It achieved its aims and stopped collecting trauma data in 2002. Since then the team have worked on a range of national audit projects and during 2009/2010 completed an audit of sepsis management in Scotland. This report was published in November 2010 and is available on the STAG website http://www.stag.scot.nhs.uk along with further information on STAG and its current programme of work.

  • Competing interests None.

  • Patient consent Data are presented as part of a National Scottish Audit. All data were anonymised before submission to the STAG central team at ISD (Information Services Division). The Caldicott guardian of each participating health board was informed of the audit and the processes involved. ISD, as part of NHS National Services Scotland, employs strict rules around information governance and the protection of information. All health information is held securely, and managed according to data protection regulations.

  • Ethics approval The STAG Sepsis Audit did not involve anything being done to patients beyond normal clinical management; it therefore did not require formal ethical approval.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement ISD are the information custodians of the STAG sepsis database; however, all participating sites are actively encouraged to request access to their own site-specific data particularly for governance or management purposes. National level data are also available for governance or research purposes; however, release of such data is managed through a strict information governance and information security policy.

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