CVPU = confused, responds to voice, responds to pain, unresponsive.
Use SpO2 Scale 2 if target saturations are 88–92% under the direction of a qualified clinician.
Each observation has a score. The total score determines the potential clinical risk and what should happen next. Higher scores also mandate closer monitoring:
Total score 0–4: low risk, ward‐based response
Score 3 in any single parameter: low–medium risk, urgent ward‐based response
Total score 5–6: medium risk, urgent response by a team with competence in the assessment and management of acutely ill patients and in recognising when the escalation to a critical care team is appropriate
Total score 7 or more: high risk, urgent response by a team which must include staff with critical care skills, including airway management.
Table 1.2 UK severity of illness classification.
Source: Reproduced with permission from the Department of Health.15
| Level 0 | Patients whose needs can be met through normal ward care in an acute hospital |
| Level 1 | Patients at risk of their condition deteriorating, or those recently relocated from higher levels of care, whose needs can be met on an acute ward with additional advice and support from the critical care team |
| Level 2 | Patients requiring more detailed observation or intervention including support for a single failing organ system or post‐operative care and those stepping down from higher levels of care |
| Level 3 | Patients requiring advanced respiratory support alone or basic respiratory support together with support of at least two organ systems. This level includes all complex patients requiring support for multi‐organ failure |
Level 2 is equivalent to HDU care.
Level 3 is equivalent to ICU care.
Early experience in the UK suggested that medical emergency teams instead of cardiac arrest teams reduced ICU mortality and the number of cardiac arrests, partly through an increase in ‘do not attempt CPR’ orders.11 In 1999, the report ‘Critical to Success – the place of efficient and effective critical care services within the acute hospital’14 re‐emphasised the concept of the patient at risk, advocating for better training of medical and nursing staff and ‘outreach’ critical care. The report commented that intensive care is something that tends to happen within four walls, but that patients should not be defined by what bed they occupy, but by their severity of illness (see Table 1.2).
Following this, ‘Comprehensive Critical Care – a review of adult critical care services’15 was published and reiterated the idea that patients should be classified according to their severity of illness and the necessary resources mobilised. With this report came funding for critical care outreach teams and an expansion in critical care beds. In the USA and parts of Europe, there is considerable provision of level 1 and 2 facilities. In most UK hospitals it is recognised that there are not enough16,17 even with the 10% increase in critical care beds that has taken place in England between 2011 and 2018.18
Although there are many different variations of early warning scores in use, it is probably the recognition of abnormal physiology, however measured, and a protocol that requires inexperienced staff to call for help that makes a difference, rather than the score itself. Patients at particular risk are recent emergency admissions, after major surgery, and following discharge from intensive care.
Do Early Warning Scores and Medical Emergency Teams Make a Difference?
Early warning scores are based on the use of aggregate weighting scoring systems, whereas the original MET calling criteria were based on single parameters, including the concern of ‘worried’ ward staff. The idea behind these trigger systems is very simple: patients often have a prolonged period of physiological instability prior to admission to the ICU, and the earlier this can be identified, the better the overall outcome.
There does not seem to be evidence that implementation of a single parameter trigger system alone improves patient outcomes, but there is evidence that the introduction of aggregate weighting scoring systems (e.g. NEWS2) improves survival and reduces unplanned ICU admissions and cardiac arrests. Likewise, when compared with standard care, medical emergency teams improve hospital survival, reduce unplanned ICU admissions, and reduce cardiac arrests, although their effect on hospital length of stay and ICU mortality remains unclear.19
The UK has focussed on identifying the deteriorating patient using aggregate weighting scoring systems, but the response to patients identified as being sick requires significant improvements. In Australia, where medical emergency teams are established, the identification of deteriorating patients using a single parameter trigger system has been less successful. Overall, for a rapid response system to be effective, it appears that a whole system approach is needed which includes trigger systems that identify deteriorating patients, clinician‐led medical emergency teams, and continuing education programmes.
ABCDE – An Overview
History, examination, differential diagnosis followed by treatment will not immediately help someone who is critically ill. Diagnosis is irrelevant when the things that kill first are literally A (airway compromise), B (breathing problems), and C (circulation problems) – in that order. What the patient needs is resuscitation not deliberation. Patients can be alert and ‘look’ well from the end of the bed, but the clue is often in objective vital signs and key test results. Box 1.2 summarises the physiological and biochemical markers of severe illness. A common theme in studies is the inability of hospital staff to recognise when a patient is at risk of deterioration, even when these abnormalities are documented.
Box 1.2 Markers of Severe Illness
Physiological
Signs of sympathetic activation e.g. tachycardia, hypertension, pale, shut down
Signs of hypoperfusion (see Chapter 5)
Signs of organ failure (see
