Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technologies. Further information about how the evidence for this briefing was selected is available on request by contacting

Published evidence

This briefing summarises 2 prospective studies and 1 multicentre retrospective observational study, which include:

  • 577 nurse events comparing the System for Electronic Notification and Documentation (SEND) with paper-based observation charts

  • 18 wards comparing the Vitalpac technology with standard care

  • 251,266 admissions comparing scores from the latest version of the National Early Warning Score (NEWS2) to the earlier version (NEWS) using either the SEND or Vitalpac systems.

These studies were carried out across 3 different NHS trusts.

Overall assessment of the evidence

There is limited published evidence on applying the technologies in this briefing to NEWS2 early warning alerts and the associated outcomes for deteriorating adult patients in hospital.

Both of the identified prospective studies reported outcomes relevant to the NHS care pathway. One study concluded that using the technology can save healthcare professionals' time when capturing and recording physiological observations and calculating a NEWS2-based score. The second prospective study found that using the technology can increase physiological observations, and reduce unplanned intensive care admissions and cardiac arrests.

The multicentre retrospective study reported clinical outcomes stratified by patients at risk of, or with confirmed, type II respiratory failure. It found that the NEWS2 oxygen saturation (SpO2) scoring modifications to NEWS do not improve discrimination of adverse outcomes in patients with documented type II respiratory failure or reduce discrimination of adverse outcomes in patients at risk of type II respiratory failure.

Future large, multicentre prospective studies in the NHS would help develop the evidence base. These should focus on relevant outcomes, such as the accuracy of NEWS2 alerts, and report clinical outcomes, such as a need for a higher level of care, cardiac arrest incidence, length of stay in hospital, and mortality, when compared with standard care. Further research could identify which groups of patients would benefit from this technology the most. A full economic evaluation of introducing such a system to the NHS is also needed, including the resources required to respond to increased alerts.

The following summarises the clinical evidence and its strengths and limitations.

Wong et al. (2017)

Intervention and comparator(s)

Intervention: SEND system (n=296). Comprising manual data entry at the patient's bedside, on a roll stand mounted tablet, alongside the vital signs monitor.

Comparator: paper-based observation chart (n=281).

Key outcomes

The observation recording process was divided into 'view chart' and 'take vital signs' tasks. The former was defined as the task of locating and opening the chart, the latter was defined as measuring and documenting vital signs. Any interruptions were timed, classified and excluded from the overall comparison.

Overall, the mean time to complete a set of physiological observations and output a NEWS2-based early warning score was lower using SEND (150 seconds; 95% confidence interval [CI]: 130 seconds to 172 seconds) than paper-based observation charts (215 seconds; 95% CI: 177 seconds to 262 seconds). The treatment effect ratio was 0.70 (95% CI: 0.57 to 0.85, p<0.001), equivalent to a 30% reduction in time.

Of the 2 tasks, 'view chart' and 'take vital signs', the greatest time savings were observed in the latter. The mean time to locate and open the chart was 13 seconds (95% CI: 10 seconds to 17 seconds) using SEND and 18 seconds (95% CI: 13 seconds to 27 seconds) using paper (treatment effect ratio 0.36, p=0.052). The mean time to measure and document a set of physiological observations was 140 seconds (95% CI: 120 seconds to 164 seconds) using SEND and 194 seconds (95% CI: 156 seconds to 241 seconds) using a paper chart (treatment effect ratio 0.72, p=0.005).

Strengths and limitations

There were a relatively large number of nurse events observed, but the study was only in 1 NHS trust, and may not be generalisable across the wider NHS.

Measurements were taken between 9am and 5pm on weekdays only, and may not reflect practice outside those times.

Nurses were aware that they were being measured, which may have altered their normal behaviour (the Hawthorne Effect).

Greengross et al. (2014) (poster)

Intervention and comparator(s)

Intervention: Vitalpac system.

Comparator: unclear.

Key outcomes

The mean number of observations per patient increased from less than 3 to more than 4 per day. The completeness of observations was sustained at more than 99%. Observations taken on time increased from 55% to 85%. Night-time observations increased from 40% of those expected to 100%. Unplanned admissions to the intensive care unit (ICU) reduced by 54%. Cardiac arrests reduced by 70%, equivalent to 120 fewer per year.

Strengths and limitations

A relatively large number of wards were observed, but the study was only in 1 NHS trust, and may not be generalisable across the wider NHS.

This study was conducted using the earlier version of NEWS scoring, but the alert system and care pathway would still be generalisable to NHS practice.

There is limited further information to make a judgement on the study's strengths and limitations. However, resource requirements such as increased availability of advanced nurse practitioners and medical response teams were not reported in this study.

Pimentel et al. (2019)

Intervention and comparator(s)

Intervention: NEWS2 scores using the SEND system in Oxford and Vitalpac system in Portsmouth.

Comparator: NEWS scores using the SEND system in Oxford and Vitalpac system in Portsmouth.

Key outcomes

Primary outcome: in-hospital death within 24 hours of an observation set.

Secondary outcomes: cardiac arrest, unanticipated ICU admission, and either cardiac arrest, unanticipated ICU admission or death within 24 hours of an observation set.

The NEWS2 adjustment for patients with or at risk of type 2 respiratory failure (T2RF) differs from NEWS in the assignment of weights to measured SpO2 (NEWS weights SpO2 values below 96%; NEWS2 below 88%). Additionally, for patients with or at risk of T2RF when receiving oxygen, NEWS2 assigns weights for SpO2 values above 92%.

Among 251,266 adult admissions, 48,898 were identified to be at risk of T2RF by diagnostic coding. In this group, NEWS2 showed statistically significant lower discrimination (c-statistic; 95% CI) for identifying in-hospital mortality within 24 hours (0.860; 0.857 to 0.864) than NEWS (0.881; 0.878 to 0.884). For 1,394 admissions with documented T2RF, discrimination was similar for both systems: NEWS2 (0.841; 0.827 to 0.855), NEWS (0.862; 0.848 to 0.875). For all secondary endpoints, NEWS2 showed no improvements in discrimination.

Strengths and limitations

This study was clearly reported and focused on patient subgroups relevant to the new SpO2 scoring method in NEWS2.

Large and clinically relevant cohorts of patients admitted with, or at risk of, T2RF were generated for analysis through the retrospective datasets. Vital signs measured throughout the patient's hospital journey were incorporated in complete observation sets. Multiple imputation methods were used to account for missing values.

Limitations identified by the authors include potential misclassification of the diagnostic codes and records of oxygen prescription that the study relied on to categorise patients with, or at risk of, T2RF. The local database did not include documentation of the 'new confusion' part of the assessment of consciousness in NEWS2, so this was omitted from the analyses. Evaluation of the cardiac arrest and unanticipated ICU admission secondary outcomes in the documented T2RF group should be interpreted with caution, given the small numbers of these events (fewer than 100).

In the documented T2RF group, NEWS and NEWS2 were comparable in terms of composite outcomes, but NEWS2 reduced the alerts by up to 39%, without increasing mortality. This may illustrate the impact of limitations of using diagnostic codes (including chronic obstructive pulmonary disease and obesity) to identify the 'at risk of T2RF' group.

Recent and ongoing studies

Bonnici et al. 2016 published the study protocol for a non-randomised stepped-wedge design evaluation of the SEND system in approximately 60,000 admissions, across 4 hospitals in one NHS trust. The company said that the results are due for submission shortly.

Other companies have also said that ongoing studies are in progress to quantify the benefits of these systems in the NHS.