Early warning system (medical)

Last updated

Early warning systems
Sample Adult Deterioration Detection System chart.jpg
A sample of an Adult Deterioration Detection System designed for Australia
Synonyms ADDS; NEWS
Reference range Physiological normal observations will generate a score of zero
Purposeto predict the risk of an adverse event or patient deterioration
Test ofvariation in physiological measures

An early warning system (EWS), sometimes called a rapid response system or track-and-trigger chart, is a clinical tool used in healthcare to anticipate patient deterioration by measuring the cumulative variation in observations, most often being patient vital signs and level of consciousness. [1] EWSs emerged in the 1990s with research finding deterioration was often preceded by abnormal vital signs. Early warning systems are heavily utilised internationally with some jurisdictions mandating their use. [2]

Contents

Early warning systems are principally designed to identify a deteriorating patient earlier, allowing for early interventions and the prevention of adverse outcomes. EWS scores give a standardised classification to the degree of physiological abnormality, with higher scores representing a higher risk of deterioration. [3]

History

The first recorded EWS was developed by a team in James Paget University Hospital, Norfolk, United Kingdom, and presented at the May 1997 conference of the Intensive Care Society. [4] [5]

With the growth in electronic health records, many services have implemented EWS systems in their digital platforms. [2]

Design and impact

Early warning systems are typically designed based on statistical analysis of the degree of variation in any given observation (such as vital signs, consciousness or demographics), and corresponding associations with adverse events (such as ICU admission, cardiac arrest, or death). The most common observations utilised in EWSs to predict deterioration is respiratory rate, followed by heart rate, oxygen saturation, temperature, systolic blood pressure, then level of consciousness (either AVPU or GCS). A small number of EWSs include age and sex as predictors of deterioration, as both have associations with in-hospital mortality, however the benefit of including age is negligible and raises significant ethical concerns. [2] [6] Most EWSs are designed to generate a score of up to three for any one given measure. Further delimitation of variation beyond 3 in either direction is believed to not add any additional benefit with the increased complexity. [6]

EWSs generate an overall score intended to indicate the risk of a patient experiencing an adverse outcome, such as requiring ICU admission, cardiac arrest, or in-hospital death. As physiological observations go outside normal parameters, numeric scores are assigned for the severity of variation. The sum of these scores across all measures is the EWS score, with scores of certain values requiring an escalation of care (such as urgent review by senior clinicians or medical emergency team activation). The inclusion of criteria requiring mandatory escalation is the source of the 'track and trigger' nickname. [3] Some EWSs include both single-parameter MET criteria (such as sudden loss of consciousness, threat to airway patency, severe tachypnoea) and composite criteria (e.g., a cumulative score of >5). [6]

Throughout the world the EWS is based on the principle that clinical deterioration can be seen through changes in multiple physiological measurements, as well as large changes within a single variable. However, the scale is calibrated to different populations and sometimes expanded to include additional parameters, specific to different parts of the world. [4] The parameters scored may vary, as well as the weighting of the scores for worsening deterioration. Some systems also assign scores to other parameters including urine output, oxygen saturation, flow rate of oxygen administration and pain scores.

There is a lack of consensus on what constitutes the 'ideal' early warning score system. Comparing different systems in clinical use shows variation in which parameters are scored and how those scores are assigned to differing levels of deterioration. [7] There is however some evidence that certain parameters are better at predicting which patients will die within 24 hours than others. [8] This has led to a call in several countries for the development of a national early warning score that would allow a standardised approach to assessing and responding to deteriorating patients. [1]

Australian psychological research has found clinician preference for graduated colouring for each measure. Chart design, such as the use of colours, has a statistically significant effect on the speed and accuracy of identifying abnormal observations. Clinicians prefer EWSs charts that have greater ease of interpretation rather than ease of recording data. Additionally, EWSs charts have been designed to only include the most important observations for detecting deterioration, as additional observations complete with clinician attention and increase the level of effort required (and potential error rate). [9]

An example of an early warning system is the VitalPAC Early Warning System (ViEWS), designed in 2010 in response to a recommendation for a national EWS by the UK National Institute for Health and Care Excellence. [6] The ViEWS chart is:

VitalPAC Early Warning System
Observation3210123
Heart rate (bpm)<4141-5051-9091-110111-130>130
Respiratory rate (bpm)<99-1112-2021-24>24
Temperature (°C)<35.135.1-36.036.1-38.038.1-39.0>39.1
Systolic blood pressure (mmHg)<9291-100101-110111-249>250
Oxygen saturation (SpO2%)<9292-9394-95>95
Oxygen requirementsAir onlyAny supplemental oxygen
Level of consciousness (AVPU)Alert (A)Verbal (V)

Pain (P) Unresponsive (U)

A ViEWS score of 5 or higher was found to be associated with an approximate 82% incidence of death within 24 hours for patients in a Medical Assessment Unit where ViEWS was developed. [6]

Recent changes have also included non-specific nursing concern in EWSs. Research suggests that nursing staff are able to identify subtle changes in patient condition before physiological deterioration, with many EWSs explicitly stating that an absence of physiological variation does not preclude escalation of care due to nursing staff's concern. Many of the 'trigger' statements (i.e., the criterion for changes to care) in EWSs reference serious worry about a patient as cause for escalation. [10] [9]

Some EWSs allow for modifications to the scoring pattern to allow for individual differences and stable pathologies. For example, the Queensland Adult Deterioration Detection System includes "Modified Calling Criteria" that allow senior medical officers to authorise changes to the normal observation ranges for a patient. [9]

Criticism

Despite their wide utilisation, there has been little research into the clinical utility of EWSs. Some studies have however found that most EWSs have little clinical effectiveness, potentially due to poor design and implementation. [2] A 2021 Cochrane review of EWSs found that there is only low certainty in the quality of research on these systems, and that the evidence may indicate little to no difference in patient outcomes; no recommendations could be concluded in either regard. [11]

A 2021 study of the Queensland Adult Deterioration Detection System (Q-ADDS) found that while the system was only able to predict approximately half of the patients in a rural or remote hospital who experienced deterioration. Compared to the National Early Warning Score from the UK, Q-ADDS had a higher rate of prediction of deterioration (46.5% Q-ADDS vs 40.8% NEWS) but a higher rate of false-positives (3.2:1 Q-ADDS vs 2.4:1 NEWS). [12]

The efficacy of EWSs in improving patient outcomes is also reliant on a number of personal and structural factors. For example, a lack of clinician knowledge of the EWS, incomplete or incorrect vital sign measurement, and the influence of power between nursing and medical staff hinder detection of clinical deterioration. [3]

Early warning system implementations

United Kingdom

NEWS2 chart National Early Warning Score chart, Royal College of Physicians, version 2.png
NEWS2 chart

A range of Early Warning Scores have been developed in response to the needs of specific patient types (e.g. PEWS for children) or to support local best practice (NEWS in the UK).

NameAcronymDescription
Paediatric Early Warning Score [13] PEWSDesigned to support the use of Track and Trigger with patients under 16, who have different normal ranges for observations
Modified Early Obstetric Warning Score [14] MEOWSDesigned to support the use of Track and Trigger for all women receiving care from maternity services
Modified Early Warning Score [15] MEWSModified to meet the requirements of many people in various clinical situations.
National Early Warning Score [16] [1] NEWS & NEWS2Developed by the Royal College of Physicians to provide a national standard in the UK for Early Warning Scores (2012 and 2017)

In the UK, the Royal College of Physicians developed the National Early Warning Score (NEWS) in 2012 to replace local or regional scores. [16] [17] [18] The NEWS score is the largest national EWS effort to date and has been adopted by some international healthcare services. [1]

A second version of the score was introduced in 2017. The revised version was optimised for the identification of sepsis, alternative oxygen targets in people with underlying lung disease, and the onset of delirium. [1] Additional implementation guidance was issued in March 2020. [19] While many hospitals still use other scores, it has been proposed that all healthcare organisations should use the same score, plus clinical judgement, for diagnosis in the interest of patient safety. [20] Clinical judgment should always be applied as a patient can deteriorate whilst presenting a score of zero. A score of zero does not indicate a stable set of vital signs. Research suggests this patient score can predict worsening condition in care home residents, and that the score could be used in care home settings as well as in hospitals. [21] [22]

Australia

Standard 8 of the National Safety and Quality Health Service (NSQHS) Standards is Recognising and Responding to Acute Deterioration, which centres on the early detection of deterioration and escalation of care. Action 8.4 of the standard explicitly states that health services are to "graphically document and track changes in agreed observations to detect acute deterioration over time, as appropriate for the patient", and outlines the minimum observations to be taken of all patients. The implementation advise specifically recommends the use of track and trigger charts (also called observation and response charts) to monitor patient physiological status, and encourages the use of digital EWS to improve early detection where properly implemented. [23]

The Australian Commission on Safety and Quality in Health Care has also released the National Consensus Statement: Essential elements for recognising and responding to acute physiological deterioration. The statement reiterates the recommendation for track and trigger charts in Australian public and private hospitals, and includes specialist charts that include lactate measurements for sepsis pathway patients. [24]

Queensland

Queensland Health has developed a range of observation charts used by most public hospitals in the state of Queensland, Australia, designed to meet the requirements of Action 8.4 of the NSQHS Standards. A very small number of Queensland Health facilities have their own EWS charts in use. [25] The family of charts includes:

  • the Queensland Adult Deterioration Detection System (Q-ADDS), with variations for certain care pathways and rural and remote facilities,
  • the Queensland Maternity Early Warning Tool (Q-MEWT), which has variations for antenatal and postnatal patients,
  • the Queensland Children's Early Warning Tool (Q-CEWT), which has variations depending on the specific child's age,
  • the Queensland Neonatal Early Warning Tool (Q-NEWT).

Q-ADDS was developed as a research project by the University of Queensland for Queensland Health to standardise 25 existing observation charts. The chart was designed primarily from The Prince Charles Hospital's observation chart (which was an adaptation of Canberra Hospital's observation chart) and the Children's Early Warning Tool by the Royal Children's Hospital, Brisbane. [9]

Q-ADDS has been shown to be able to predict deterioration approximately half of the time, however no other EWS has shown any marked improvement in accuracy over Q-ADDS. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Triage</span> Emergency medical process

In medicine, triage is a process by which care providers such as medical professionals and those with first aid knowledge determine the order of priority for providing treatment to injured individuals and/or inform the rationing of limited supplies so that they go to those who can most benefit from it. Triage is usually relied upon when there are more injured individuals than available care providers, or when there are more injured individuals than supplies to treat them.

<span class="mw-page-title-main">Cardiac arrest</span> Sudden failure of heart beat

Cardiac arrest is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly circulate around the body and the blood flow to the brain and other organs is decreased. When the brain does not receive enough blood, this can cause a person to lose consciousness and brain cells can start to die due to lack of oxygen. Coma and persistent vegetative state may result from cardiac arrest. Cardiac arrest is also identified by a lack of central pulses and abnormal or absent breathing.

<span class="mw-page-title-main">Sepsis</span> Life-threatening response to infection

Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs.

<span class="mw-page-title-main">Extracorporeal membrane oxygenation</span> Technique of providing both cardiac and respiratory support

Extracorporeal membrane oxygenation (ECMO), is a form of extracorporeal life support, providing prolonged cardiac and respiratory support to persons whose heart and lungs are unable to provide an adequate amount of oxygen, gas exchange or blood supply (perfusion) to sustain life. The technology for ECMO is largely derived from cardiopulmonary bypass, which provides shorter-term support with arrested native circulation. The device used is a membrane oxygenator, also known as an artificial lung.

<span class="mw-page-title-main">Spirometry</span> Pulmonary function test

Spirometry is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is helpful in assessing breathing patterns that identify conditions such as asthma, pulmonary fibrosis, cystic fibrosis, and COPD. It is also helpful as part of a system of health surveillance, in which breathing patterns are measured over time.

<span class="mw-page-title-main">Acute pancreatitis</span> Medical condition

Acute pancreatitis (AP) is a sudden inflammation of the pancreas. Causes include a gallstone impacted in the common bile duct or the pancreatic duct, heavy alcohol use, systemic disease, trauma, elevated calcium levels, hypertriglyceridemia, certain medications, hereditary causes and, in children, mumps. Acute pancreatitis may be a single event, it may be recurrent, or it may progress to chronic pancreatitis and/or pancreatic failure.

<span class="mw-page-title-main">Vital signs</span> Group of medical indicators

Vital signs are a group of the four to six most crucial medical signs that indicate the status of the body's vital (life-sustaining) functions. These measurements are taken to help assess the general physical health of a person, give clues to possible diseases, and show progress toward recovery. The normal ranges for a person's vital signs vary with age, weight, sex, and overall health.

The respiratory rate is the rate at which breathing occurs; it is set and controlled by the respiratory center of the brain. A person's respiratory rate is usually measured in breaths per minute.

<span class="mw-page-title-main">SOFA score</span> Medical assessment

The sequential organ failure assessment score, previously known as the sepsis-related organ failure assessment score, is used to track a person's status during the stay in an intensive care unit (ICU) to determine the extent of a person's organ function or rate of failure. The score is based on six different scores, one each for the respiratory, cardiovascular, hepatic, coagulation, renal and neurological systems.

Hospital emergency codes are coded messages often announced over a public address system of a hospital to alert staff to various classes of on-site emergencies. The use of codes is intended to convey essential information quickly and with minimal misunderstanding to staff while preventing stress and panic among visitors to the hospital. Such codes are sometimes posted on placards throughout the hospital or are printed on employee identification badges for ready reference.

The Garling Report is a 2008 report prepared by the office of the Australian Commissioner Peter Garling, SC following a series of high-profile medical mishaps in the New South Wales public hospital system. For the duration of the commission, it was well covered by mass media. Its final 139 recommendations stimulated considerable discussion and controversy.

<span class="mw-page-title-main">Trauma in children</span> Medical condition

Trauma in children, also known as pediatric trauma, refers to a traumatic injury that happens to an infant, child or adolescent. Because of anatomical and physiological differences between children and adults the care and management of this population differs.

<span class="mw-page-title-main">Monitoring (medicine)</span> Observation of a disease, condition or one or several medical parameters over time

In medicine, monitoring is the observation of a disease, condition or one or several medical parameters over time.

Pupillometry, the measurement of pupil size and reactivity, is a key part of the clinical neurological exam for patients with a wide variety of neurological injuries. It is also used in psychology.

Vital Sign Alert System is an alert system designed by nurses at Sentara Norfolk General Hospital in Norfolk, Virginia. The alert system, which replaced an ineffective early warning scoring (EWS) system, is a unique creation designed specifically to enhance patient monitoring on medical–surgical and step-down nursing units without increasing the nurse's workload.

A rapid response system (RRS) is a system implemented in many hospitals designed to identify and respond to patients with early signs of clinical deterioration on non-intensive care units with the goal of preventing respiratory or cardiac arrest. A rapid response system consists of two clinical components, an afferent component, an efferent component, and two organizational components – process improvement and administrative.

Pediatric early warning signs (PEWS) are clinical manifestations that indicate rapid deterioration in pediatric patients, infancy to adolescence. A PEWS score or PEWS system refers to assessment tools that incorporate the clinical manifestations that have the greatest impact on patient outcome.

Respiratory compromise describes a deterioration in respiratory function with a high likelihood of rapid progression to respiratory failure and death. Respiratory failure occurs when inadequate gas exchange by the respiratory system occurs, with a low oxygen level or a high carbon dioxide level.

The 4 'A's Test (4AT) is a bedside medical scale used to help determine if a person has positive signs for delirium. The 4AT also includes cognitive test items, making it suitable also for use as a rapid test for cognitive impairment.

ReSPECT stands for Recommended Summary Plan for Emergency Care and Treatment. It is an emergency care and treatment plan (ECTP) used in parts of the United Kingdom, in which personalized recommendations for future emergency clinical care and treatment are created through discussion between health care professionals and a person. These recommendations are then documented on a ReSPECT form.

References

  1. 1 2 3 4 5 Williams B (ed)., ed. (2017). National Early Warning Score (NEWS) 2 – Standardising the assessment of acute illness severity in the NHS. ISBN   978-1-86016-682-2.
  2. 1 2 3 4 Gerry, Stephen; Bonnici, Timothy; Birks, Jacqueline; Kirtley, Shona; Virdee, Pradeep S; Watkinson, Peter J; Collins, Gary S (20 May 2020). "Early warning scores for detecting deterioration in adult hospital patients: systematic review and critical appraisal of methodology". BMJ. 369: m1501. doi:10.1136/bmj.m1501. ISSN   1756-1833. PMC   7238890 . PMID   32434791.
  3. 1 2 3 Saab, Mohamad M.; McCarthy, Bridie; Andrews, Tom; Savage, Eileen; Drummond, Frances J.; Walshe, Nuala; Forde, Mary; Breen, Dorothy; Henn, Patrick; Drennan, Jonathan; Hegarty, Josephine (November 2017). "The effect of adult Early Warning Systems education on nurses' knowledge, confidence and clinical performance: A systematic review". Journal of Advanced Nursing. 73 (11): 2506–2521. doi:10.1111/jan.13322. hdl:10468/5370. ISSN   0309-2402. PMID   28440892.
  4. 1 2 Wright MM, Morgan RJ, Williams F (1997). "An early warning scoring system for detecting developing critical illness". Clin Intensive Care. 8: 100. doi:10.3109/tcic.8.2.93.110 (inactive 1 November 2024).{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link)
  5. ↑ Gao, H; McDonnell, A; Harrison, DA; Moore, T; Adam, S; Daly, K; Esmonde, L; Goldhill, DR; Parry, GJ; Rashidian, A; Subbe, CP; Harvey, S (April 2007). "Systematic review and evaluation of physiological track and trigger warning systems for identifying at-risk patients on the ward". Intensive Care Medicine. 33 (4): 667–79. doi:10.1007/s00134-007-0532-3. PMID   17318499. S2CID   785355.
  6. 1 2 3 4 5 Prytherch, David R.; Smith, Gary B.; Schmidt, Paul E.; Featherstone, Peter I. (August 2010). "ViEWS—Towards a national early warning score for detecting adult inpatient deterioration". Resuscitation. 81 (8): 932–937. doi:10.1016/j.resuscitation.2010.04.014. PMID   20637974.
  7. ↑ Psirides A, Hill J, Hurford S (2013). "A review of rapid response team activation parameters in New Zealand hospitals". Resuscitation. 84 (8): 1040–1044. doi:10.1016/j.resuscitation.2013.01.022. PMID   23376581.
  8. ↑ Prytherch DR, Smith GB, Schmidt PE, Featherstone PI (2010). "ViEWS—Towards a national early warning score for detecting adult inpatient deterioration". Resuscitation. 81 (8): 932–937. doi:10.1016/j.resuscitation.2010.04.014. PMID   20637974.
  9. 1 2 3 4 Preece, Megan; Horswill, Mark; Hill, Andrew; Watson, Marcus (May 2010). "The Adult Deterioration Detection System (ADDS) Chart" (PDF). Australian Commission on Safety and Quality in Health Care . Retrieved 10 January 2025.
  10. ↑ Douw, Gooske; Schoonhoven, Lisette; Holwerda, Tineke; Huisman-de Waal, Getty; van Zanten, Arthur R H; van Achterberg, Theo; van der Hoeven, Johannes G (December 2015). "Nurses' worry or concern and early recognition of deteriorating patients on general wards in acute care hospitals: a systematic review". Critical Care. 19 (1): 230. doi: 10.1186/s13054-015-0950-5 . ISSN   1364-8535. PMC   4461986 . PMID   25990249.
  11. ↑ McGaughey, Jennifer; Fergusson, Dean A; Van Bogaert, Peter; Rose, Louise (22 November 2021). Cochrane Central Editorial Service (ed.). "Early warning systems and rapid response systems for the prevention of patient deterioration on acute adult hospital wards". Cochrane Database of Systematic Reviews. 2025 (1): CD005529. doi:10.1002/14651858.CD005529.pub3. PMC   8608437 . PMID   34808700.
  12. 1 2 Le Lagadec, Marie Danielle; Dwyer, Trudy; Browne, Matthew (December 2021). "Patient Deterioration in Australian Regional and Rural Hospitals: Is the Queensland Adult Deterioration Detection System the Criterion Standard?". Journal of Patient Safety. 17 (8): e1879 –e1883. doi:10.1097/PTS.0000000000000689. ISSN   1549-8425. PMID   32175963.
  13. ↑ Cadman, Jeni. "PEWS – NHS Institute for Innovation and Improvement". www.institute.nhs.uk. Archived from the original on 15 April 2016. Retrieved 10 May 2016.
  14. ↑ "MEOWS – Norfolk and Norwich University Hospital MEOWS Guidelines". www.nnuh.nhs.uk. Retrieved 10 May 2016.[ permanent dead link ]
  15. ↑ Subbe C.P.; Kruger M.; Gemmel L. (2001). "Validation of a modified Early Warning Score in medical admissions". Quarterly Journal of Medicine. 94 (10): 521–6. doi:10.1093/qjmed/94.10.521. PMID   11588210.
  16. 1 2 National Early Warning Score Development and Implementation Group (NEWSDIG) (2012). National Early Warning Score (NEWS): standardising the assessment of acute-illness severity in the NHS. London: Royal College of Physicians. ISBN   978-1-86016-471-2.
  17. ↑ National Institute for Health and Clinical Excellence . Clinical guideline 50: Acutely ill patients in hospital . London, 2007.
  18. ↑ "Acute care toolkit 6: the medical patient at risk: recognition and care of the seriously ill or deteriorating medical patient" (PDF). Royal College of Physicians of London. May 2013.
  19. ↑ "National Early Warning Score (NEWS) 2. Standardising the assessment of acute illness severity in the NHS. Additional Implementation Guidance March 2020" . Retrieved 2 June 2020.
  20. ↑ Inada-Kim, Matt; Nsutebu, Emmanuel (20 March 2018). "NEWS 2: an opportunity to standardise the management of deterioration and sepsis". BMJ. 360: k1260. doi:10.1136/bmj.k1260. PMID   29559439. S2CID   4210138.
  21. ↑ Deeney, Brendan (27 September 2023). "Is NEWS2 accurate for care home residents in hospital?". NIHR Evidence. doi:10.3310/nihrevidence_60021 . Retrieved 27 September 2023.
  22. ↑ Barker, Robert (2023). "National Early Warning Scores Following Emergency Hospital Transfer: Implications for Care Home Residents". Journal of the American Medical Directors Association. 24 (5): 653–656. doi:10.1016/j.jamda.2023.01.013. PMID   36822235.
  23. ↑ "National Safety and Quality Health Service Standards". Australian Commission on Safety and Quality in Health Care (2nd ed.). 2021. Retrieved 10 January 2025.
  24. ↑ "National Consensus Statement: Essential elements for recognising and responding to acute physiological deterioration". Australian Commission on Safety and Quality in Health Care (3rd ed.). 2021. Retrieved 10 January 2025.
  25. ↑ "Recognising and Responding to Acute Deterioration Audit Tool Definitions" (PDF). Clinical Excellence Queensland. Queensland Health. 2018. Retrieved 10 January 2025.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.