Review Article

Performance of the Afferent Limb of Rapid Response Systems in Managing Deteriorating Patients: A Systematic Review

Table 1

Summary of relevant studies on monitoring deteriorating patients.

Year
Authors
Country
Aim
Design
Sample
Outcome measures
Findings

2005
Hillman et al. [33]
Australia
To investigate the effectiveness of the MET system in reducing the incidence of cardiac arrests, unplanned admissions to ICU, and deaths
Cluster randomized controlled trial in 23 hospitals
MERIT (medical early response, intervention, and therapy) study: 11 hospitals with the CAT (56,756 patients), 12 hospitals with the MET system (68,376 patients)
Cardiac arrests, unplanned ICU admissions, or unexpected deaths
(i) No substantial difference in the incidence of cardiac arrests, unplanned ICU admissions, or unexpected deaths
(ii) The MET was involved in only 30% of patients with the calling criteria before ICU admissions
(iii) Several cases of cardiac arrests (53%, 46%), unplanned ICU admissions (21%, 36%), and unexpected deaths (34%, 25%) were identified less than 15 min before the event in the control and MET hospitals, respectively

2008
McGain et al. [34]
Australia
To describe factors associated with incomplete postoperative documentation of vital signs
Retrospective observational study in five hospitals
211 adult patients after major surgery
Documentation of medical and nursing reviews and vital signs
(i) In the first 3 days after surgery, 17% of patient records had complete documentation of vital signs (BP, HR, RR, T°, and SpO2) and medical and nursing reviews
(ii) The most undocumented observation was the RR (15.4%)

2008
Van Leuvan and Mitchell [35]
Australia
To determine the frequency of vital sign measurements and differences in the frequency between specific vital signs
Retrospective observational study in one tertiary hospital
1,597 unique vital signs recorded in 62 patients
Readings of vital signs from all patient charts
(i) Documentation of vital signs was significantly lower for RR (1.0 reading/day) vs. BP (5.0 readings/day), HR (4.4 readings/day), and T° (4.2 readings/day), for all comparisons

2009
Chen et al. [36]
Australia
To examine the effect of the MET system introduction on the documentation rate of vital signs during the MERIT study
Post hoc analysis in 23 hospitals
Vital signs (HR, RR, and SBP) 15 min–24 h before an adverse event (cardiac arrest, death, or unexpected ICU admission) or an emergency team call
Association between undocumented vital signs, hospital characteristics, and MET allocation
(i) The lack of at least one vital sign in 77% of patients with adverse events
(ii) The RR was the lowest documented sign in the control and MET hospitals and was three times missing than the HR and SBP
(iii) The MET system improved documentation of the RR and SBP before the emergency team review () and documentation over time ()

2012
Ludikhuize et al. [37]
Netherlands
To describe measurements and documentation of vital signs and usefulness of the MEWS in detecting deteriorating patients by nurses
Retrospective observational study in one university hospital
204 patients in general wards with SAEs (2,688 measures of one or more vital signs 48 h before the event)
All documented vital parameters
(i) 81% of patients had a MEWS ≥3 at least once 48 h before the event (cardiopulmonary arrest, unplanned ICU admission, unexpected death, and emergency surgery)
(ii) Even with the MEWS ≥3, recordings of vital signs were incomplete: RR, diuresis, and SpO2 were documented in only 30–66% of assessments

2012
Pantazopoulos et al. [38]
Greece
To test the relationship between nurse demographics and correct identification of clinical situations warranting specific actions and MET activation
Cross-sectional survey in one tertiary hospital
94 nurses in general wards
Factors influencing MET activation by nurses
(i) Only 43% of nurses recorded vital signs every 6 h
(ii) RR and GCS were the less recorded vital signs
(iii) Nurses with a 4-year educational course identified a higher rate of emergencies requiring MET activation; those with training in BLS and ALS courses showed better management of cardiac or respiratory emergencies

2013
Tirkkonen et al. [39]
Finland
To study the factors associated with delayed MET activation and increased hospital mortality
Prospective observational study in one tertiary hospital
A cohort of 569 MET reviews for 458 patients with 5.9% of general ward beds equipped with automatic noninvasive monitoring of vital functions
Documentation of vital signs and vital dysfunctions 6 h before a MET call with reference to automated patient monitoring
(i) Vital signs were more frequently documented in patients with automated monitoring vs. normal monitoring (96% vs. 74%, )
(ii) The RR was alarmingly low (75% vs. 17%, ) 0–6 h before MET activation
(iii) ALF occurred more often among automated monitored vs. normal monitored patients (81% vs. 53%, )

2014
Ludikhuize et al. [40]
Netherlands
To study the effect of three times daily measurements (protocolized group) of the MEWS vs. measurements clinically indicated (control group) on implementation of the RRS
A quasi–experimental study in one university hospital
Sample of patients in 10 protocolized wards and in 8 control wards (372 vs. 432, respectively) Measurements in patients in protocolized and in control wards (3,585 vs. 3,013, respectively)(i) Nurses estimated the MEWS from vital signs in 70% (2513/3,585) of patients in the protocolized wards vs. 2% (65/3,013) in the control group ()
(ii) Compliance with the measurement regime (≥3 times per day) was 68% (819/1,205), measurements in the control group were 4% (47/1,232) only
(iii) In protocolized wards, there were twice as much RRT calls per admission

2016
Cardona-Morrell et al. [41]
Australia
To establish vital signs monitoring practices of nurses and adherence to the health service protocol
Prospective observational study in one teaching hospital
42 general ward nurses with 441 patient interactions
Vital signs monitoring (HR, BP, RR, T°, SpO2, level of consciousness, urine output, and pain)
(i) Vital signs were assessed in 52% (229/441) of interactions
(ii) The minimum five measures (BP, HR, RR, T°, and SpO2) were taken in 6–21% of instances of vital signs monitoring

2016
Considine et al. [42]
Australia
To explore documentation of physiological observations by nurses in acute care
Prospective observational study in one public hospital
178 patients of ward units and emergency department
Physiological observations in the preceding 24 h (ward patients) or 8 h (emergency department)
(i) The most documented vital signs were RR, SpO2, HR, and SBP while the least documented were T° and conscious state
(ii) There was evidence of one or more abnormal physiological parameters in 79.8% (142/178) of patients with documented abnormalities in only 19.7% of them (28/142)

2016
Smith and Aitken [43]
UK
To investigate the use of a single-parameter TTS for implementation of the NEWS tool by nurses. To report the characteristics of patients and triggers. To explore barriers and facilitators to patient monitoring
Mixed methods study in one university hospital
263 physiological triggers of 74 patients from general wards
Cross-sectional survey of 105 nurses
Barriers and facilitators to monitoring a deteriorating patient with a single-parameter TTS
Nursing staff perceptions of the TTS
(i) The most recorded physiological trigger was the SBP (59%, 156/263) and the least recorded was the RR (14%, 36/263)
(ii) Barriers and facilitators to monitor and escalate abnormal vital signs of patients were as follows:
(a) Lack of equipment for vital signs monitoring (equipment)
(b) Barriers to both effective monitoring of patients and the escalation process (workload)
(c) Conflicting priorities between different members of the nursing staff (interactions between the staff)
(d) Patients that may not consent to record observations (interactions with patients)

MET: medical emergency team; ICU: intensive care unit; CAT: cardiac arrest team; min: minutes; BP: blood pressure; HR: heart rate; RR: respiratory rate; T°: temperature; SpO2: peripheral oxygen saturation; SBP: systolic blood pressure; h: hours; MEWS: modified early warning score; SAEs: serious adverse events; GCS: Glasgow Coma Scale; BLS: basic life support; ALS: advanced life support; ALF: afferent limb failure; RRS: rapid response system; TTS: track and trigger system; NEWS: national early warning score.