The optimal threshold for prompt clinical review: An external validation study of the national early warning score.

AIMS AND OBJECTIVES: The aim of this study was to determine the optimal threshold for national early warning score in clinical practice. BACKGROUND: The national early warning score is an aggregate early warning score aiming to predict patient mortality. Studies validating national early warning score did not use standardised patient outcomes or did not always include clinical workload in their results. Since all patients with a positive national early warning score require a clinical workup, it is crucial to determine the optimal threshold to limit false-positive alerts. DESIGN: An external validation study using retrospectively collected data of patient admissions in six Belgian hospitals. METHODS: We adhered to the STARD guideline for reporting. Two sample groups were selected: the cross-sectional sample (admitted patients, 1 day every 4 months) and the serious adverse event sample (all patients with unexpected death, cardiac arrest and unplanned admission to the intensive care unit). The maximum registered national early warning score value was collected in both groups. Predictive values were used as estimates for clinical workload. RESULTS: We collected 1,523 in the cross-sectional sample and 390 patients in the serious adverse event sample. A national early warning score ≥5 had a predictive value of 6.8% and a negative predictive value of 99.5% to predict unexpected death, cardiac arrest with cardiopulmonary resuscitation or unplanned admission to intensive care (AUROC 0.841). The performance of national early warning score differed between outcome measures. Considering the predictive value, the optimal threshold for national early warning score is ≥5. CONCLUSIONS: We validated national early warning score to be applied in general hospital wards and confirmed the optimal threshold (≥5). RELEVANCE TO CLINICAL PRACTICE: When a patient has a national early warning score <5, we may assume that in the next 24 hr this patient is less likely to die unexpectedly, receive cardiopulmonary resuscitation or be transferred to the ICU. Because of the significant number of false positives when national early warning score is ≥5, hospitals should create workable guidelines for clinical practice.

The impact of nurse staffing levels and nurse's education on patient mortality in medical and surgical wards: an observational multicentre study.

BACKGROUND: Growing evidence indicates that improved nurse staffing in acute hospitals is associated with lower hospital mortality. Current research is limited to studies using hospital level data or without proper adjustment for confounders which makes the translation to practice difficult. METHOD: In this observational study we analysed retrospectively the control group of a stepped wedge randomised controlled trial concerning 14 medical and 14 surgical wards in seven Belgian hospitals. All patients admitted to these wards during the control period were included in this study. Pregnant patients or children below 17 years of age were excluded. In all patients, we collected age, crude ward mortality, unexpected death, cardiac arrest with Cardiopulmonary Resuscitation (CPR), and unplanned admission to the Intensive Care Unit (ICU). A composite mortality measure was constructed including unexpected death and death up to 72 h after cardiac arrest with CPR or unplanned ICU admission. Every 4 months we obtained, from 30 consecutive patient admissions across all wards, the Charlson comorbidity index. The amount of nursing hours per patient days (NHPPD) were calculated every day for 15 days, once every 4 months. Data were aggregated to the ward level resulting in 68 estimates across wards and time. Linear mixed models were used since they are most appropriate in case of clustered and repeated measures data. RESULTS: The unexpected death rate was 1.80 per 1000 patients. Up to 0.76 per 1000 patients died after CPR and 0.62 per 1000 patients died after unplanned admission to the ICU. The mean composite mortality was 3.18 per 1000 patients. The mean NHPPD and proportion of nurse Bachelor hours were respectively 2.48 and 0.59. We found a negative association between the nursing hours per patient day and the composite mortality rate adjusted for possible confounders (B = - 2.771, p = 0.002). The proportion of nurse Bachelor hours was negatively correlated with the composite mortality rate in the same analysis (B = - 8.845, p = 0.023). Using the regression equation, we calculated theoretically optimal NHPPDs. CONCLUSIONS: This study confirms the association between higher nurse staffing levels and lower patient mortality controlled for relevant confounders.

An intervention including the national early warning score improves patient monitoring practice and reduces mortality: A cluster randomized controlled trial.

AIMS: To investigate the impact of the national early warning score on the frequency and the quality of vital sign registration and to study the association between protocol compliance and patient mortality. DESIGN: We conducted a post hoc data analysis of a stepped wedge cluster randomized controlled trial (RCT) in six hospitals. METHODS: All adult, non-pregnant patients admitted to 24 wards were included. The intervention comprised an observation protocol using the national early warning score combined with a pragmatic medical response strategy. Data collection lasted from October 2013-May 2015. Patient comorbidity scores and vital signs were sampled every 4 months on each ward. All vital signs in the 24 hr before a serious adverse event were collected. RESULTS: Patients (N = 60,956) were included of which 32,722 in the intervention group. Comorbidity scores were sampled in 3,600 patients and vital signs in 2,951 patients. In 668 patients, vital signs were collected before a serious adverse event. The mean number of vital signs per observation increased significantly in the intervention group. The observation frequency increased in patients with a serious adverse event and decreased in patients without a serious adverse event. Protocol compliance was negatively associated with patient mortality adjusted for comorbidity and age. CONCLUSION: Our intervention improved patient monitoring practice and reduced mortality. IMPACT: The impact of early warning scores on patient monitoring practice and patient outcomes remains unclear. Our intervention improved the observation of patients and reduced patient mortality. These results could support hospitals in their decision to implement rapid response systems. TRIAL REGISTRATION: We have registered this study in the clinicaltrials.gov database (identifier: NCT01949025).

In-hospital mortality after serious adverse events on medical and surgical nursing units: a mixed methods study.

AIMS AND OBJECTIVES: To investigate the circumstances of nursing care eight hours before serious adverse events (=SAE's) on medical and surgical nursing units with subsequent in-hospital mortality in order to identify the extent to which these SAE's were potentially preventable. BACKGROUND: The prevention of SAE 's in acute care is coming under increasing scrutiny, while the role nursing care plays in the prevention of acute critical deterioration of patients is unclear. METHODS: Retrospective review of patient records of 63 SAE's in a Belgian teaching hospital where death was the final outcome following a cardiac arrest team call or unplanned ICU admission from an acute care unit. Data from chart reviews were combined with data regarding working conditions on the nursing unit at the time of the events and experts' opinions regarding the preventability of the outcomes. Finally, a pilot survey of staff nurses about their experiences with deteriorating patients and knowledge of vital signs and call criteria was conducted independently of the chart abstractions and case reviews. RESULTS: Experts were almost five times more likely to designate a case as potentially preventable when a cardiac arrest team call was the terminal event and were 40% less likely to designate a case as potentially preventable when more observations were documented in patient records. Survey results revealed that nurses were often unaware that their patients were deteriorating before the crisis. Nurses also reported threshold levels for concern for abnormal vital signs that suggested they would call for assistance relatively late in clinical crises. CONCLUSION: Renewed attention to accurate recording, documentation and interpretation of vital signs in hospital nursing practice appears needed. RELEVANCE TO CLINICAL PRACTICE: Timely detection of deteriorating patients to assist staff to improve their outcomes appears to be jeopardised by a number of practices and factors and merits deeper study.

The introduction of a rapid response system in acute hospitals: A pragmatic stepped wedge cluster randomised controlled trial.

AIM: Deterioration of hospitalised patients is often missed, misinterpreted, and mismanaged. Rapid Response Systems (RRSs) have been proposed to solve this problem. This study aimed to investigate the effect of an RRS on the incidence of unexpected death, cardiac arrest with cardiopulmonary resuscitation (CPR), and unplanned intensive care unit (ICU) admission. METHODS: We conducted a stepped wedge cluster randomised controlled trial including 14 Belgian acute care hospitals with two medical and two surgical wards each. The intervention comprised a standardised observation and communication protocol including a pragmatic medical response strategy. Comorbidity and nurse staff levels were collected as potential confounders. RESULTS: Twenty-eight wards of seven hospitals were studied from October 2013 until May 2015 and included in the final analysis. The control group contained 34,267 patient admissions and the intervention group 35,389. When adjusted for clustering and study time, we found no significant difference between the control and intervention group in unexpected death rates (1.5 vs 0.7/1000, OR 0.82, 95%CI 0.34-1.95), cardiac arrest rates (1.3 vs 1.0/1000, OR 0.71, 95%CI 0.33-1.52) or unplanned ICU admissions (6.5 vs 10.3/1000, OR 1.23, 95%CI 0.91-1.65). CONCLUSION: Our intervention had no significant effect on the incidence of unexpected death, cardiac arrest or unplanned ICU admission when adjusted for clustering and study time. We found a lower than expected baseline incidence of unexpected death and cardiac arrest rates which reduced the statistical power significantly in this study.

Six-day postoperative impact of a standardized nurse observation and escalation protocol: a preintervention and postintervention study.

PURPOSE: The purpose of the study is to determine the impact of a standardized nurse observation and escalation protocol on observation frequency, the measurement of vital signs, and the incidence of in-hospital mortality and resurgery. METHODS: This is a preintervention and postintervention study by analysis of patient records for a 6-day postoperative period of all adult patients hospitalized in 4 hospital wards after surgery during a preintervention (November 2010 to March 2011; n = 2359) and postintervention (November 2011 to March 2012; n = 1888) period implementing a standardized nurse observation and escalation protocol including the Modified Early Warning Score. RESULTS: The mean patient observation frequency per nursing shift increased from 0.9076 (95% confidence interval [CI], 0.8921-0.9231) preintervention to 0.9940 (95% CI, 0.9708-1.0172; P < .001) postintervention and was lower in case of 6-day postoperative mortality (0.6686 [95% CI, 0.4984-0.8388] vs other patients 0.9475 [95% CI, 0.9340-0.9610]; P = .003) or resurgery (0.8402 [95% CI, 0.7894-0.8909] vs other patients 0.9564 [95% CI, 0.9378-0.9657]; P = .003). The mean number of vital signs measured per observation episode increased from a mean of 1.81 (95% CI, 1.79-1.83) preintervention to 2.45 (95% CI, 2.39-2.51; P < .001) postintervention. The relative risk reduction was 73.7% (95% CI, 22.8-91.0; P = .015) for 6-day postoperative in-hospital mortality and 30.9% (95% CI, 9.5-47.2; P = .007) for 6-day postoperative resurgery.

Segment and joint angles of hind limb during bipedal and quadrupedal walking of the bonobo (Pan paniscus).

We describe segment angles (trunk, thigh, shank, and foot) and joint angles (hip, knee, and ankle) for the hind limbs of bonobos walking bipedally ("bent-hip bent-knee walking," 17 sequences) and quadrupedally (33 sequences). Data were based on video recordings (50 Hz) of nine subjects in a lateral view, walking at voluntary speed. The major differences between bipedal and quadrupedal walking are found in the trunk, thigh, and hip angles. During bipedal walking, the trunk is approximately 33-41 degrees more erect than during quadrupedal locomotion, although it is considerably more bent forward than in normal human locomotion. Moreover, during bipedal walking, the hip has a smaller range of motion (by 12 degrees ) and is more extended (by 20-35 degrees ) than during quadrupedal walking. In general, angle profiles in bonobos are much more variable than in humans. Intralimb phase relationships of subsequent joint angles show that hip-knee coordination is similar for bipedal and quadrupedal walking, and resembles the human pattern. The coordination between knee and ankle differs much more from the human pattern. Based on joint angles observed throughout stance phase and on the estimation of functional leg length, an efficient inverted pendulum mechanism is not expected in bonobos.