The fifth vital sign? Nurse worry predicts inpatient deterioration within 24 hours

Abstract

Introduction: Identification of hospitalized patients with suddenly unfavorable clinical course remains challenging. Models using objective data elements from the electronic health record may miss important sources of information available to nurses.

Methods: We recorded nurses' perception of patient potential for deterioration in 2 medical and 2 surgical adult hospital units using a 5-point score at the start of the shift (the Worry Factor [WF]), and any time a change or an increase was noted by the nurse. Cases were evaluated by three reviewers. Intensive care unit (ICU) transfers were also tracked.

Results: 31 159 patient-shifts were recorded for 3185 unique patients during 3551 hospitalizations, with 169 total outcome events. Out of 492 potential deterioration events identified, 380 (77%) were confirmed by reviewers as true deterioration events. Likelihood ratios for ICU transfer were 17.8 (15.2-20.9) in the 24 hours following a WF > 2, and 40.4 (27.1-60.1) following a WF > 3. Accuracy rates were significantly higher in nurses with over a year of experience (68% vs 79%, P = 0.04). The area under the receiver operator characteristic curve (AUROC) was 0.92 for the prediction of ICU transfer within 24 hours.

Discussion: This is a higher accuracy than most published early warning scores.

Conclusion: Nurses' pattern recognition and sense of worry can provide important information for the detection of acute physiological deterioration and should be included in the electronic medical record.

Keywords: clinical deterioration; informatics; inpatient; nursing; physiological pattern recognition.

Figure 1.

Worry Factor Score criteria. The Worry Factor Score is a very simple, 5-level scale. Scores 0 or 1 (above the dotted line) indicate the scoring nurse does not believe the patient is actively deteriorating. Scores of 2–4 (below the dotted line) indicate increasing level of worry or certainty that a patient is deteriorating.

Figure 2.

Worry Factor (WF) accuracy by nurse experience. Percentage of potential deteriorations confirmed by reviewers. The graph shows the total percentage of instances that were considered real deterioration by the reviewers, by years of experience of the nurse filling out the worry factor. The difference is statistically significant between less than 1 year of experience, and 1 or more.

Figure 3.

Provider and nurse actions by worry factor (WF) score and number of instances the WF increased during a shift. Number of potential deteriorations and nursing and provider response to increasing worry factor. The graph shows the total number of instances of increased WF by the WF score reached. The line indicates the total number of potential deterioration events (instances of increased worry factor by the nurse). The number of potential deterioration events is smaller for the higher WF scores (more severe deterioration events are rarer). The bars illustrate the proportion of actions taken by the nurse: “no action” means the nurses did not call the provider, “Provider was called” means the provider was notified by the nurse but did not evaluate the patient at the bedside, “Provider was called and came to bedside” means that the provider was notified and performed a bedside evaluation.