Safer and more efficient vital signs monitoring protocols to identify the deteriorating patients in the general hospital ward: an observational study

Background: The frequency at which patients should have their vital signs (e.g. blood pressure, pulse, oxygen saturation) measured on hospital wards is currently unknown. Current NHS monitoring protocols are based on expert opinion but supported by little empirical evidence. The challenge is finding the balance between insufficient monitoring (risking missing early signs of deterioration and delays in treatment) and over-observation of stable patients (wasting resources needed in other aspects of care).

Objective: Provide an evidence-based approach to creating monitoring protocols based on a patient's risk of deterioration and link these to nursing workload and economic impact.

Design: Our study consisted of two parts: (a) an observational study of nursing staff to ascertain the time to perform vital sign observations; and (b) a retrospective study of historic data on patient admissions exploring the relationships between NEWS and risk of outcome over time. These were underpinned by opinions and experiences from stakeholders.

Setting and participants: Observational study: observed nursing staff on 16 randomly selected adult general wards at four acute NHS hospitals.
Retrospective study: extracted, linked and analysed routinely collected data from two large NHS acute trusts; data from over 400,000 patient admissions and 9,000,000 vital sign observations.

Results: Observational study found a variety of practices, with two hospitals having registered nurses take the majority of vital sign observations and two favouring healthcare assistants or student nurses. However, whoever took the observations spent roughly the same length of time. The average was 5:01 minutes per observation over a "round" including time to locate and prepare the equipment and travel to the patient area.
Retrospective study created survival models predicting the risk of outcomes over time since the patient was last observed. For low-risk patients, there was little difference in risk between 4h and 24h post-observation.

Conclusions: We explored several different scenarios with our stakeholders (clinicians and patients), based on how "risk" could be managed in different ways. Vital sign observations are often done more frequently than necessary from a bald assessment of the patient's risk and we show that a maximum threshold of risk could theoretically be achieved with less resource. Existing resources could therefore be redeployed within a changed protocol to achieve better outcomes for some patients without compromising the safety of the rest.
Our work supports the approach of the current monitoring protocol, whereby patients' NEWS2 score guides observation frequency. Existing practice is to observe higher-risk patients more frequently and our findings have shown that this is objectively justified. It is worth noting that important nurse-patient interactions take place during vital sign monitoring and should not be eliminated under new monitoring processes.
Our study contributes to the existing evidence on how vital sign observations should be scheduled. However, ultimately, it is for the relevant professionals to decide how our work should be used.