Review Article | Open Access
Performance of the Afferent Limb of Rapid Response Systems in Managing Deteriorating Patients: A Systematic Review
Introduction. The clinical components of the rapid response system (RRS) are the afferent limb, to ensure identification of in-hospital patients who deteriorate and activation of a response, and the efferent limb, to provide the response. This review aims to evaluate the factors that influence the performance of the afferent limb in managing deteriorating ward patients and their effects on patient outcomes. Methods. A systematic review was performed for the years 1995–2017 by employing five electronic databases. Articles were included assessing the ability of the ward staffs to monitor, recognize, and escalate care to patient deterioration. The findings were summarized using a narrative approach. Results. Thirty-one studies met the inclusion criteria. The analysis revealed major themes enclosing several factors affecting management of patients having sudden deterioration. The monitoring and recognition process was conditioned by the lack of recording of physiological parameters, the influence of facilitators, including staff education and training, and barriers, including human and environmental factors, and poor compliance with the calling criteria. The escalation of care process highlighted the influence of cultural barriers and personal judgment on RRS activation. Mainly, delayed team calls were factors strongly associated with the increased risk of unplanned admissions to the intensive care unit and length of stay, hospital length of stay and mortality, and 30-day mortality. Conclusions. A combination of factors affects the timely identification and response to sudden deterioration by general ward staffs, leading to suboptimal care of patients, delayed or failed activation of RRS teams, and increased risks of worsening outcomes. The research efforts and clinical involvement to improve the governance of the factors limiting the performance of the afferent limb may ensure proper management of hospitalized patients showing physiological deterioration.
On general hospital wards, the timely treatment of patient deterioration before the onset of serious adverse events (SAEs) is achievable by alerting emergency teams of critical care clinicians. The Medical Emergency Team (MET) has been adopted, the first of these teams, in 1989 at the Liverpool Hospital in Sydney, Australia [1, 2], to supplement or replace the Cardiac Arrest Team (CAT) . Afterward, the Rapid Response Team (RRT) in the United States of America (USA), the Critical Care Outreach Service (CCOS) in the United Kingdom (UK), and the Critical Care Response Team (CCRT) in Canada [4–7] have been proposed. In 2006, the concept of the Rapid Response System (RRS) has merged the previous models of emergency teams by integrating four components [8, 9]. The afferent limb includes ward physicians and nurses to identify at-risk patients and to trigger a response based on the calling criteria. The efferent limb ensures the response with emergency teams of critical care doctors and nurses. The last two are the administrative limb, for coordinating all system components, and the quality improvement limb, for improving the function of the RRS [8, 9]. The calling criteria include vital signs, physiological parameters, and the level of consciousness, the objective criteria, and the staff “worried” criterion or concern about the patient, the subjective criterion. These tools are named the physiological track and trigger warning systems (TTSs) and consist of single-parameter systems, multiple-parameter systems, aggregate weighted scoring systems, and combination systems [10, 11].
The RRS has been designed to detect and respond to deteriorating patients outside the intensive care unit (ICU) [8, 9]. The concept of patient deterioration has been first emphasized by Schein et al.  by suggesting that derangement of clinical signs often anticipates cardiopulmonary arrest. Franklin and Mathew  have reported patient deterioration documented by physicians or nurses within 6 hours of cardiac arrest, emphasizing the failure to respond to cardiopulmonary, neurological, or respiratory deterioration. Jones et al.  have described a deteriorating patient as one with an increased risk of morbidity, organ dysfunction, protracted hospital stay, disability, or death. Mostly, the early detection and treatment of patients at risk of clinical deterioration improve their outcomes . A prospective cohort study involving 48 hospitals in the UK has shown high 90-day mortality among deteriorating ward patients, whereas early ICU admission within 4 hours of the assessment has strongly reduced mortality .
Clinical performance measurement, in a health system intervention, involves how measures are created, how they are implemented, and the evidence of their potential benefits and harms . The RRS aims to reduce SAEs including cardiac arrest, unplanned admissions to the ICU, and death [8, 9]; however, the effectiveness of RRSs in improving patient outcomes remains controversial [18–20]. Regardless, evidence from recent meta-analyses [21–23] has suggested that implementation of RRSs has substantially reduced non-ICU cardiac arrests, hospital mortality, and unexpected mortality in the adult population without an evident effect on ICU admission rates. Afferent limb failure (ALF) has been indicated as the presence of documented MET calling criteria without a MET call before an in-hospital serious event  and has been proposed as a performance measure of RRSs . Practically, the performance of the afferent limb is difficult to evaluate. Winters et al.  have indicated facilitators and barriers to system implementation, such as acceptance and leadership of the RRS, rates of calling the RRS, and trigger mechanisms. Besides, different factors may encourage or inhibit the effective use of the MET system by ward nurses . The dynamic of the afferent limb relies on the interaction and collaboration between physicians and nurses with different clinical skills. The activity of these clinicians involves sequential passages: monitoring of vital signs and physiologic parameters, recognizing of patient deterioration, implementation of the treatment for at-risk patients, and the request for help with activation of RRS teams (Figure 1). This review aims to evaluate the factors that influence the performance of the afferent limb, affecting the ability to monitor, recognize, and escalate care to deteriorating ward patients, and their effects on patient outcomes.
2.1. Study Design
2.2. Eligibility Criteria and Study Selection
The eligibility criteria to include studies agreed with the SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research type) tool  (Table B in Supplementary Materials). The review included primary research studies on factors influencing the ability to monitor, recognize, and escalate care to patient deterioration; assessing the effects of these factors on patient outcomes; conducted on general wards; involving adult patients (>18 years of age), ward physicians, or ward nurses in acute hospitals; and published in English between 1995 and 2017. Lee et al.  first outlined, in 1995, the concept of the RRS as critical care clinicians responding to deteriorating patients outside the ICU, so the present research included papers following this work. The exclusion criteria included editorials, commentaries, opinion papers, reviews, pediatric patients, and non-English languages.
2.3. Search Strategy
A systematic search covered the literature published between 1 January 1995 and 31 December 2017 by using five electronic databases. The web search contemplated the bibliographic databases CINAHL, Medline, ScienceDirect, Scopus, and the search engine Google Scholar. In addition, the reference lists of the selected papers were examined to identify further relevant studies. The search involved different keywords combined with the Boolean logic. The following terms were included: deteriorating patients, rapid response systems, medical emergency team, rapid response team, critical care outreach service, critical care response team, patient monitoring, patient recognizing, escalation of care, and general wards (Table C in Supplementary Materials).
2.4. Quality Assessment
All included papers were evaluated by the Quality Assessment Tool for Studies with Diverse Designs (QATSDD) instrument , which allows the quality assessment of studies with different methodological designs, such as quantitative, qualitative, and mixed methods studies. The QATSDD includes 14–16 items with a three-point scale by assigning a score to each study.
2.5. Data Extraction and Synthesis
The records identified by the search were imported into the reference management software Zotero. After screening the title and the abstract of each article, the entire manuscripts suitable for inclusion were read. One single researcher extracted the data according to predefined criteria, including authors, year and country, aim and design, sample and outcome measures, and findings. All the eligible studies were assessed for their quality. The reviewed studies presented heterogeneous designs. Therefore, the synthesis of the data followed the narrative synthesis proposed by Popay et al. . This approach to a systematic review uses words and texts instead of numbers to summarize and explain the results of the synthesis.
3.1. Study Selection
The search from all sources generated 11,640 articles. The removal of duplicates and nonrelevant papers produced 121 potential studies. Following a full-text review, 31 articles were included (Figure 2).
3.2. Study Characteristics
The studies represented 11 countries with the majority originated from Australia (), followed by the Netherlands (), the UK (), the USA (), and Canada () with one study each from Brazil, Denmark, Finland, Greece, Italy, and Spain. The study setting included community, teaching, and university hospitals () and one simulation scenario (27 quantitative, two qualitative, and two mixed methods studies). The sample size ranged from 14 ward staff members to 125,132 patients of the MERIT trial. The population included patients, physicians, and nurses on general hospital wards (Table D in Supplementary Materials).
3.3. Study Quality Assessment
The average QATSDD score was 53.34% with a range between 40.47% and 73.8%. The overall quality of the studies was moderate to strong. Few studies reported the evidence of the sample size, the target group of a reasonable size, and relevance of the user involvement in the design. The statistical assessment of validity and reliability was poor. Most studies described adequately the research settings and procedures for data collection and recruitment.
3.4. Synthesis of Results
Previous studies identified three stages that affect the efficiency of the afferent limb, such as monitoring, recognizing, and escalating care to patient deterioration [25, 32]. These findings were consistent with the objectives of the present review. Therefore, the reported studies [33–63] followed these stages and were presented in the table format (Tables 1–3) and in the text format. Besides, the common areas within the studies were categorized into themes relevant to the objectives of the review.
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.
EWS: early warning score; TTS: track and trigger system; HR: heart rate; RR: respiratory rate; SBP: systolic blood pressure; T°: temperature; SpO2: peripheral oxygen saturation; MEWS: modified early warning score; SBAR: situation-background-assessment-recommendation; ICU: intensive care unit; NEWS: national early warning score; MET: medical emergency team; RRT: rapid response team; CM: critical messages; h: hours.
MET: medical emergency team; RRS: rapid response system; min: minutes; ICU: intensive care unit; LOS: length of stay; OR: odds ratio; h: hours; ALF: afferent limb failure; HR: heart rate; MAP: mean artery pressure; RR: respiratory rate; SpO2: peripheral oxygen saturation; MERIT: medical early response, intervention, and therapy; RRT: rapid response team; METal: medical emergency team alert; SBP: systolic blood pressure; APACHE II: acute physiologic assessment and chronic health evaluation; SAPS II: simplified acute physiology score; MODS: multiple organ dysfunction syndrome; RRC: rapid response call; UCR: urgent clinical review.
3.5. Monitoring Deteriorating Patients
Eleven papers investigated monitoring of deteriorating patients, treating the following themes: lack of recording, poor documentation of the respiratory rate, and influence of facilitators and barriers. Overall, the lack of recording of physiological measurements was observed in all reported papers [33–43]. In the MERIT trial , monitoring, recording, and responding to vital signs changes were lacking. Indeed, MET calls were documented in only 30% of patients with the calling criteria before ICU admissions, and several patients with documented MET criteria were identified less than 15 minutes before an adverse event. McGain et al.  reported complete documentation of medical and nursing review and vital signs in only 17% of patients after major surgery in five hospitals. Similarly, Chen et al.  showed the lack of at least one vital sign in 77% of patients with adverse events. Ludikhuize et al.  documented the complete recording of vital signs in 30–66% of assessments. Differently, Pantazopoulos et al.  described documentation of vital signs every 6 hours performed only by 43% of nurses. Tirkkonen et al.  assessed suboptimal documentation of vital signs in normal wards versus wards with automated noninvasive monitoring (74% vs. 96%, ), especially relevant for the respiratory rate (17% vs. 75%, ). Besides, ALF was more common among patients with automated versus traditional monitoring (81% vs. 53%, ), emphasizing the role of timely interventions to obtain benefits from extensive monitoring, and was independently related to increased hospital mortality. The work of Cardona-Morrell et al.  evidenced vital signs assessments in 52% of nurse-patient interactions. They reported five vital signs (blood pressure, heart rate, respiratory rate, temperature, and SpO2) monitored on average in 21% of cases and only in 6% of patients in a surgical ward. Lastly, Considine et al.  reported evidence of abnormal physiological parameters in 79.8% of patients, but only in 19.7% of them were abnormalities documented.
Seven papers indicated poor documentation of the respiratory rate. Indeed, this vital sign was the less documented, the recording rate was 14–17% [34–36, 38, 39, 43], and only one report indicated a higher recording rate (30–66%) .
Four papers underlined the role of facilitators and barriers [36, 38, 40, 43]. A post hoc study  found that missing documentation of vital signs was significantly reduced with the introduction of the MET system. Pantazopoulos et al.  observed a high level of judgment, including MET activation, in nurses graduated from a 4-year against a 2-year degree course; besides, those trained with Basic Life Support and Advanced Life Support courses identified and managed cardiac or respiratory emergencies better. Ludikhuize et al.  reported better calculations of Modified Early Warning Score by nurses in protocolized wards (three times daily measurements of vital signs) versus control wards (70% vs. 2%, ). Besides, compliance with measurements of vital signs was better in protocolized wards versus the control group (68% vs. 4%) with more reliable RRT activation. Lastly, Smith and Aitken  identified factors interfering with monitoring and escalation of clinical deterioration, including the lack of monitoring equipment, the workload, interactions and conflicts between the staff, and interactions with patients.
3.6. Recognizing Deteriorating Patients
Six papers described recognition of deteriorating patients, treating the following themes: compliance with the calling criteria and impact of communication. Five papers explored the compliance with the Early Warning Scores (EWSs), reporting poor adherence with the protocol [44–48]. The EWSs utilize deviation of multiple parameters from the normal ones, weighted and converted into a single score, with higher risks of clinical deterioration for higher scores. The Early Warning Scoring system was developed in 1997 by Morgan et al. . Later, it was proposed the Modified Early Warning Score (MEWS)  and the National Early Warning Score (NEWS) adopted across the National Health Service (NHS) in the UK . In this review, Donohue and Endacott  underlined the use of a visual evalution by comparing the patient's clinical condition over time by nurses who used the MEWS to quantify deterioration after recognition of the clinical instability. A simulation study  reported the MEWS correctly determined by only 11% of the trained nurses; however, the trained group assessed the patient immediately (77% vs. 58%, ) and measured the respiratory rate twice as frequently compared to the nontrained nurses (53% vs. 25%, ). Kolic et al. found  an incorrect calculation of the NEWS in 18.9% of patients with an inadequate clinical response in 25.9% of cases and scoring errors more frequently with higher NEW scores. The study by van Galen et al.  showed vital signs monitoring performed as agreed with the doctors in only 41% of patients; besides, 43% of measurements had a critical MEWS (≥3) 48 hours before ICU admissions, but only 1% of measurements had a correct calculation. Lastly, Petersen et al.  documented low adherence to the EWS monitoring frequency often during busy periods and at night, low rate calls of the junior doctors for patients with a high EWS, and barriers for negative feelings toward the MET system by nurses.
One paper highlighted the role of communication between clinicians. Wong et al.  reported messages between nurses and physicians with information on the calling criteria before the ICU transfer in about 39% of patients, but only 45% of messages included two or more vital signs.
3.7. Escalating Care to Deteriorating Patients
Fourteen papers explored escalation of care to deteriorating patients, treating the following themes: influence of cultural barriers and personal judgment, delayed team calls, and effects of delays on clinical outcomes. Four papers identified cultural barriers preventing timely escalation of care [50, 52, 55, 59]. Jones et al.  described the traditional approach of initially calling ward doctors by nurses (72%) who would call the MET for a patient they were worried, even with normal vital signs (56%). A survey of Canadian nurses  underlined the fear of criticism (15.4%) and the hierarchical model of alerting the responsible physician before the MET call (75.9%), also if respondents (48%) would activate the MET system for a patient they were concerned about. Local sociocultural factors and intraprofessional hierarchies were other barriers to RRS activation . Radeschi et al.  indicated the covering physician as the major barriers to MET activation for nurses (62%); besides, the reluctance to the MET call in a patient fulfilling the calling criteria (21%) was more frequent for nurses than for doctors.
Two papers identified the impact of personal judgment on team activation. Shearer et al.  reported missing RRS calls because the bedside staff believed the clinical situation was under control (51.8%) or RRS activation was not necessary for staff experience with patient deterioration (14%). Davies et al.  showed low adherence (25%) to six criteria for RRT activation related to different importance given by ward staffs to the different calling criteria.
Nine papers reported delayed or missed MET calls from 21.4% to 57% of patients who had documented calling criteria with delayed team alerts ranging from 15 minutes to 24 hours [51, 53–56, 58, 60–62]. Eight papers assessed the patient outcomes related to delayed calls [53, 54, 56, 58, 60–63]. Calzavacca et al.  found less delayed MET activation, 5 years after RRS implementation, in a recent cohort versus a control cohort of patients (22% vs. 40.3%, ). They reported delayed MET activation associated with the increased risk of unplanned ICU admission (OR 1.79, 95% CI 1.33–2.93, ) and hospital mortality (OR 2.18, 95% CI 1.42–3.33, ). Similarly, Trinkle and Flabouris  documented 22.8% of ALF in patients with adverse events that, compared to patients without ALF, presented a higher risk of unscheduled ICU admissions (34.4 vs. 22.5%, ) and hospital mortality (52.5% vs. 31.9%, ) through multiple, as opposed to single, time periods. Boniatti et al.  found 21.4% of delayed calls, significantly higher for physicians versus nurses (29.2% vs. 17.6%, ); besides, 30-day mortality after the MET review was higher in patients with delayed compared to timely MET activation (61.8% vs. 41.9%, ). A post hoc analysis of the MERIT study  reported delayed calls in 30.2% of patients with the increased risk of unplanned ICU admissions (OR 1.56, 95% CI 1.23–2.04, ) and death (OR 1.79, 95% CI 1.43–2.27, ) in the control and MET hospitals. Barwise et al.  described delayed RRT activation in 57% of patients associated with higher hospital mortality (15% vs. 8%, OR 1.6, ), 30-day mortality (20% vs. 13%, OR 1.4, ), and hospital length of stay (LOS) (7 vs. 6 days, relative prolongation 1.10, ) compared to the no-delay group. Castano-Avila et al.  reported delayed alerts (41.25%) in patients admitted to the ICU. These admissions showed a significantly higher APACHE II score, SAPS II score, MODS rate, and nonsignificant longer length of ICU stay. Gupta et al.  showed 24.6% of delayed rapid response calls related to the increase of in-hospital mortality (34.7% vs. 21.2%, ) and longer hospitalization (11.6 vs. 8.4 days, ). Lastly, Sprogis et al.  underlined a high frequency of delayed escalation of care by ward clinicians with 58% of patients without a documented response by nurses to first urgent clinical review criteria, and 12% of hospital mortality for patients requiring MET activation.
This review explores the literature on different aspects interfering with the performance of the afferent limb of RRSs. The research identifies several factors enabling or inhibiting the ability of ward staffs to monitor and record physiologic parameters, recognize physiological deterioration, and escalate care to unexpectedly deteriorating patients.
Monitoring of deteriorating patients in this review emphasized the lack of recording since measurements and documentation of physiological parameters had high variability, and they were rarely recorded and often undocumented [33–43]. The literature suggests the need for more reliable monitoring of vital signs. In an ICU, patients have continuous monitoring of multiple physiological parameters. In a general ward, monitoring may be intermittent or continuous, manual or automated, and often includes only traditional vital signs. Intermittent monitoring is not always adequate to highlight timely changes in vital signs. Nonetheless, evidence of effectiveness was insufficient to recommend continuous vital signs monitoring as routine practice in general wards . The monitoring process required both a correct interpretation of physiologic disorders and an adequate response to these observations . The optimal frequency of vital sign measurements to increase the likelihood of detecting clinical deterioration is unclear. In the UK, the minimum frequency of monitoring should be at least every 12 hours . An Australian consensus statement suggested the frequency of observation at least once per 8-hour shift , while another statement suggested the intermittent assessment of vital signs should occur every 12 hours or preferably every 6 hours . The trends of vital signs compared to the value of vital signs alone substantially improved the accuracy of deterioration detection and were independent predictors of critical illness in ward patients . Basic biochemistry and hematology results were other relevant signs for early detection of the patient in crisis . Spanish papers emphasized an alert system to avoid emergency ICU admissions with early identification of patient deterioration based on laboratory tests selected for organ failure. The authors reported a decrease in the ICU mortality rate after admissions of at-risk patients by evaluating the alteration of these laboratory tests  and by extending this evaluation to weekends and public holidays . Ward nurses were indicated as responsible for the assessment, recording, and documentation of vital signs ; however, evidence indicates their poor compliance with vital signs monitoring. Chua et al.  described the incomplete vital signs monitoring and interpretation by nurses for the excessive workload and the lack of recognition of the importance of vital signs, particularly the respiratory rate. Similarly, Mok et al.  explored nurses’ attitudes revealing the limited understanding of key indicators of deterioration. Furthermore, nurses indicated monitoring of vital signs as being time consuming, overwhelming, and unnecessary for patients with stable conditions [74, 75].
Poor documentation of the respiratory rate in the reviewed studies underlined frequent and repeated omissions of this measurement during vital signs monitoring [34–36, 38, 43]. Comparable findings are demonstrated by other researchers. The respiratory rate was the most commonly undocumented observation with the missing rate ranging from 0.8% to 61.8% of patients in different hospitals . Elliott  reported poor understanding regarding the importance of the respiratory rate as vital signs by nurses for inadequate knowledge of the respiratory rate assessment, nurses’ perception of the patient’s acuity, and the lack of time. Moreover, the respiratory rate was claimed as an early indicator of serious illness, such as shock, sepsis, and respiratory insufficiency, since its increase reflects hypoxia and metabolic acidosis .
Facilitators and barriers to the monitoring process highlighted different issues in the selected studies. RRS implementation substantially increased the vital signs recording , while higher degrees and training courses helped nurses to better identify emergencies and patient deterioration . Standardized measurements of the vital signs and MEWS allowed more efficient activation of ward physicians and RRS teams by nurses . The failure to monitor was correlated to the lack of monitoring equipment and human and environmental interfering factors . Published studies identify comparable results. The nurses attending a MET training session showed a greater intention to call the MET and correctly identified most MET activation criteria . Moreover, strategies as educational development and modification of clinical processes of patient monitoring could improve recognizing and managing of deteriorating patients by nurses .
Recognition of deteriorating patients in this review suggested poor compliance with the EWS protocol. Indeed, there was a low percentage of correct measurements, particularly with high EWS ranges, worsening of clinical responses at weekends, increased mortality with incorrect responses, and low agreement with the monitoring frequency, particularly during busy periods and at night [44, 46–48]. Furthermore, the favorable effects of the training to improve compliance with the EWS were also described . Previous papers suggest similar issues. The EWSs had a good predictive value for patient deterioration and improve patient outcomes, but inaccurate recordings or inappropriate reactions to abnormal scores could reduce these benefits . Besides, the efficiency of the EWSs depended on the patient cohort, facilities available, and the staff training and attitude . Regardless, the EWSs could not replace clinical judgment and clinical skills [80, 81].
Poor communication between nurses and physicians in the reviewed studies was expressed by the low quality of critical messages on patient deterioration and the positive relationship between the quality of messages and hospital survival . Similarly, a previous study indicated the role of inadequate communication between clinicians in management of patient deterioration .
Escalation of care to deteriorating patients in the present review underlined the effects of cultural barriers and personal judgment on the response. Cultural barriers as the nurses’ hierarchical approach, intraprofessional hierarchies between the ward clinicians, and reluctance to call the MET prevented timely response activation by the ward staffs [50, 52, 55, 59]. Subjective judgment induced a failure to respond when the staff judged the clinical situation to be under control in the ward and poor compliance toward RRS activation for low adherence to the calling criteria [55, 57]. Analogously, the previous study by Odell et al.  suggested that nurses used intuitive judgment to assess deterioration, using vital signs to confirm their findings. Another study  indicated hierarchical organization and poor interprofessional communication as causes of delayed escalation, underlining also the role of the high workload and overconfidence.
Delayed team calls in the reviewed studies involved several patients (21-57%) who fulfilled the calling criteria for emergency teams [51, 53–56, 58, 60–62]. Mostly, there was a strong increase in the risks of unplanned ICU admissions [53, 54, 58], hospital LOS [60, 62], hospital mortality [53, 54, 58, 60, 62], 30-day mortality [56, 60], and prolonged ICU LOS  related to delayed or missed alerts. The main trigger for timely MET calls was the concern about the patient for nurses, and delayed calls were higher for physicians than for nurses . Similar findings are underlined by previous studies. A multicenter study  in 17 ICUs demonstrated 71% of admissions with unnecessary delays for organizational issues rather than patient-related problems. Similarly, Sankey et al.  reported 64.6% of delayed escalation of care greater than 4 hours in 793 patients before the ICU transfer and a substantial increase in in-hospital mortality for delays over 12 hours. The reasons for delayed team calls are linked to the difference between the diverse calling criteria used and the role of the staff “worried” criterion to activate the MET system, which involves ward nurses much more frequently than doctors. Santiano et al.  reported that the “worried” criterion was the most frequent reason for MET calls (29% of 3,194 team calls) in six acute hospitals. They also underlined that this subjective criterion often relied on clinical intuition and judgment of ward nurses. Similarly, Mezzaroba et al.  confirmed as the most frequent reason (37.7%) for emergency team activation was the ward team seriously concerned about the patient’s clinical instability. Furthermore, the subjective worry or concern criterion by nurses was considered relevant in the early recognition and treatment of deteriorating patients .
This review presents several weaknesses. The clinical performance of the afferent limb must consider the differences in warning tools, activation thresholds, and team compositions, doctors, nurses, or other clinicians, physician-led versus nurse-led. Second, the heterogeneity of interventions, study designs, and populations precluded a meta-analysis. Last, one single researcher performed the present review. The credibility of a systematic review may be limited by inappropriate eligibility criteria, the inadequate literature search, or the failure to optimally synthesize results . Moreover, data extraction by two independent reviewers should be used to reduce errors . Nonetheless, a recent paper  reported the great prevalence of extraction errors in systematic reviews, although these errors seem to have only a moderate impact on the results and conclusion of the reviews. This research, conducted by one single reviewer, clearly adheres to the protocol, the inclusion and exclusion criteria, the literature search, and the synthesis of results by increasing the transparency and credibility of the process.
The bedside treatment of patient deterioration on general wards is a complex issue involving physicians and nurses with different expertise. A combination of factors affects the timely identification and response to sudden deterioration by general ward staffs, leading to suboptimal care of patients, delayed or failed activation of RRS teams, and increased risks of worsening outcomes. The research efforts and clinical involvement to improve the governance of the factors limiting the performance of the afferent limb may ensure proper management of hospitalized patients showing physiological deterioration.
Conflicts of Interest
The author declares no conflicts of interest.
Supplementary data associated with this article can be found in Tables A, B, C, and D. (Supplementary Materials)
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