Hideo Tohira

Audiovisual feedback device use by health care professionals during CPR: A systematic review and meta-analysis of randomised and non-randomised trials

OBJECTIVES A systematic appraisal of the literature to determine if audiovisual feedback devices can improve CPR quality delivered by health care practitioners (HCPs) and/or survival outcomes following cardiac arrest. METHODS We searched the Cochrane Central Register of Controlled Studies (CENTRAL) on The Cochrane Library, MEDLINE, EMBASE, CIHAHL and AUSTHEALTH in May 2013 for experimental and observational (human or manikin) studies examining the effect of the use of audiovisual feedback devices by HCPs in simulated and actual cardiac arrest. The primary outcome for human studies was survival to hospital discharge with good neurologic outcome. Secondary outcomes were other survival data and quality of CPR performance; the latter was also reported for manikin studies. RESULTS Three human interventional studies (n=2100) and 17 manikin studies met the inclusion criteria. Overall quality of included studies was poor, with significant clinical heterogeneity. All three human studies reported no significant change to any survival outcomes despite improvement in chest compression (CC) depth by 2.5 mm (95% CI 0.9-4.3), CC rate 6 min(-1) closer to 100 (95% CI 2.4-10.7) and a reduction in no-flow fraction by 1.9% on meta-analysis. Manikin studies showed similar improvements in CC parameters. CONCLUSION In both manikin and human studies, feedback during resuscitation can result in rescuers providing CC parameters closer to recommendations. There is no evidence that this translates into improved patient outcomes. The reason for this is not yet evident and further patient centered research is warranted.

Systematic review of predictive performance of injury severity scoring tools.

Many injury severity scoring tools have been developed over the past few decades. These tools include the Injury Severity Score (ISS), New ISS (NISS), Trauma and Injury Severity Score (TRISS) and International Classification of Diseases (ICD)-based Injury Severity Score (ICISS). Although many studies have endeavored to determine the ability of these tools to predict the mortality of injured patients, their results have been inconsistent. We conducted a systematic review to summarize the predictive performances of these tools and explore the heterogeneity among studies. We defined a relevant article as any research article that reported the area under the Receiver Operating Characteristic curve as a measure of predictive performance. We conducted an online search using MEDLINE and Embase. We evaluated the quality of each relevant article using a quality assessment questionnaire consisting of 10 questions. The total number of positive answers was reported as the quality score of the study. Meta-analysis was not performed due to the heterogeneity among studies. We identified 64 relevant articles with 157 AUROCs of the tools. The median number of positive answers to the questionnaire was 5, ranging from 2 to 8. Less than half of the relevant studies reported the version of the Abbreviated Injury Scale (AIS) and/or ICD (37.5%). The heterogeneity among the studies could be observed in a broad distribution of crude mortality rates of study data, ranging from 1% to 38%. The NISS was mostly reported to perform better than the ISS when predicting the mortality of blunt trauma patients. The relative performance of the ICSS against the AIS-based tools was inconclusive because of the scarcity of studies. The performance of the ICISS appeared to be unstable because the performance could be altered by the type of formula and survival risk ratios used. In conclusion, high-quality studies were limited. The NISS might perform better in the mortality prediction of blunt injuries than the ISS. Additional studies are required to standardize the derivation of the ICISS and determine the relative performance of the ICISS against the AIS-based tools.

Cardiopulmonary resuscitation quality and patient survival outcome in cardiac arrest: A systematic review and meta-analysis

AIM To conduct a systematic review and meta-analysis to determine whether cardiopulmonary resuscitation (CPR) quality, as indicated by parameters such as chest compression depth, compression rate and compression fraction, is associated with patient survival from cardiac arrest. METHODS Five databases were searched (MEDLINE, Embase, CINAHL, Scopus and Cochrane) as well as the grey literature (MedNar). To satisfy inclusion criteria, studies had to document human cases of in- or out-of hospital cardiac arrest where CPR quality had been recorded using an automated device and linked to patient survival. Where indicated (I(2)<75%), meta-analysis was undertaken to examine the relationship between individual CPR quality parameters and either survival to hospital discharge (STHD) or return of spontaneous circulation (ROSC). RESULTS Database searching yielded 8,842 unique citations, resulting in the inclusion of 22 relevant articles. Thirteen were included in the meta-analysis. Chest compression depth was significantly associated with STHD (mean difference (MD) between survivors and non-survivors 2.59 mm, 95% CI: 0.71, 4.47); and with ROSC (MD 0.99 mm, 95% CI: 0.04, 1.93). Within the range of approximately 100-120 compressions per minute (cpm), compression rate was significantly associated with STHD; survivors demonstrated a lower mean compression rate than non-survivors (MD -1.17 cpm, 95% CI: -2.21, -0.14). Compression fraction could not be examined by meta-analysis due to high heterogeneity, however a higher fraction appeared to be associated with survival in cases with a shockable initial rhythm. CONCLUSIONS Chest compression depth and rate were associated with survival outcomes. More studies with consistent reporting of data are required for other quality parameters.

A systematic review of air pollution and incidence of out-of-hospital cardiac arrest

Introduction Studies have linked air pollution with the incidence of acute coronary artery events and cardiovascular mortality but the association with out-of-hospital cardiac arrest (OHCA) is less clear. Aim To examine the association of air pollution with the occurrence of OHCA. Methods Electronic bibliographic databases (until February 2013) were searched. Search terms included common air pollutants and OHCA. Studies of patients with implantable cardioverter defibrillators and OHCA not attended by paramedics were excluded. Two independent reviewers (THKT and TAW) identified potential studies. Methodological quality was assessed by the Newcastle-Ottawa Scale. Results Of 849 studies, 8 met the selection criteria. Significant associations between particulate matter (PM) exposure (especially PM2.5) and OHCA were found in 5 studies. An increase of OHCA risk ranged from 2.4% to 7% per interquartile increase in average PM exposure on the same day and up to 4 days prior to the event. A large study found ozone increased the risk of OHCA within 3 h prior to the event. The strongest risk OR of 3.8–4.6% per 20 parts per billion ozone increase of the average level was within 2 h prior to the event. Similarly, another study found an increased risk of 18% within 2 days prior to the event. Conclusions Larger studies have suggested an increased risk of OHCA with air pollution exposure from PM2.5 and ozone.

Assessment of Effective Hepatic Blood Flow in Critically Ill Patients by Noninvasive Pulse Dye-Densitometry

Abstact.Purpose: Effective hepatic blood flow (EHBF) is thought to reflect splanchnic perfusion and the metabolic state of the liver. This study was conducted to examine the relationship between cardiac output (CO) and EHBF using pulse dye-densitometry (PDD) in nonseptic and septic patients, and to assess the prognostic value of this relationship. Methods: The subjects were 33 critically ill patients, 16 of whom met the criteria for sepsis. Indocyanine green (ICG) was given via a central venous catheter to each patient. CO (l/min) and EHBF (l/min) were assessed with PDD. Results: CO and EHBF were significantly correlated in the nonseptic patients (r = 0.92, P < 0.001), but not in the septic patients (r = 0.38, P = 0.15). The ratio of EHBF to CO (EHBF/CO) in the septic patients was significantly lower than that in the nonseptic patients (0.08 ± 0.04 vs 0.22 ± 0.05; P < 0.001). Moreover, in the septic patients, the EHBF/CO ratios of nonsurvivors were significantly lower than those of survivors (0.06 ± 0.04 vs 010 ± 0.02; P < 0.01). Conclusions: In nonseptic patients, the EHBF decreased in relation to the CO. However, the EHBF/CO ratio of septic patients was lower than that of nonseptic patients, suggesting that inadequate splanchnic perfusion or metabolic change occurs in septic patients. Furthermore, the lower EHBF/CO ratio was related with a fatal outcome in septic patients. PDD could be a clinically useful method of assessing splanchnic conditions in critically ill patients.

The impact of new prehospital practitioners on ambulance transportation to the emergency department: A systematic review and meta-analysis

Objective To conduct a systematic review and meta-analysis to examine the impact of new prehospital practitioners (NPPs), including emergency care practitioners (EmCPs), paramedic practitioners and extended care paramedics (ECPs), on ambulance transportation to the emergency department (ED). Methods We searched MEDLINE, Embase, CINAHL and AUSTHealth databases, and hand searched emergency medicine journals and journal reference lists for relevant papers. To be included, studies were required to target one type of NPP and compare outcomes such as the frequencies of conveyance to the ED, discharge at scene, subsequent ED attendance and/or appropriateness of care between NPPs and conventional ambulance crews. Three investigators independently selected relevant studies. The risk of bias in individual studies was assessed using a validated checklist. We conducted meta-analyses for comparisons which had acceptable heterogeneity (I2<75%) and reported pooled estimates of ORs with 95% CIs. Results 13 studies were identified from 16 584 citation reports. EmCPs were most frequently studied. The majority of studies (77%) did not fully report important potential confounders. NPPs were less likely to convey patients to the ED and more likely to discharge patients at the scene than conventional ambulance crews. Pooled ORs for conveyance to the ED and discharge at the scene by ECPs were 0.09 (95% CI 0.04 to 0.18) and 10.5 (95% CI 5.8 to 19), respectively. The evidence for subsequent ED attendance and appropriateness of care was equivocal. Conclusions The NPP schemes reduced transport to the ED; however, the appropriateness of the decision of the NPPs and the safety of patients were not well supported by the reported studies.

Evidence-based paramedic models of care to reduce unnecessary emergency department attendance – feasibility and safety

BackgroundAs demand for Emergency Department (ED) services continues to exceed increases explained by population growth, strategies to reduce ED presentations are being explored. The concept of ambulance paramedics providing an alternative model of care to the current default ‘see and transport to ED’ has intuitive appeal and has been implemented in several locations around the world. The premise is that for certain non-critically ill patients, the Extended Care Paramedic (ECP) can either ‘see and treat’ or ‘see and refer’ to another primary or community care practitioner, rather than transport to hospital. However, there has been little rigorous investigation of which types of patients can be safely identified and managed in the community, or the impact of ECPs on ED attendance.Methods/DesignSt John Ambulance Western Australia paramedics will indicate on the electronic patient care record (e-PCR) of patients attended in the Perth metropolitan area if they consider them to be suitable to be managed in the community. ‘Follow-up’ will examine these patients using ED data to determine the patient’s disposition from the ED. A clinical panel will then develop a protocol to identify those patients who can be safely managed in the community. Paramedics will then assess patients against the derived ECP protocols and identify those deemed suitable to ‘see and treat’ or ‘see and refer’. The ED disposition (and other clinical outcomes) of these ‘ECP protocol identified’ patients will enable us to assess whether it would have been appropriate to manage these patients in the community. We will also ‘track’ re-presentations to EDs within seven days of the initial presentation. This is a ‘virtual experiment’ with no direct involvement of patients or changes in clinical practice. A systems modelling approach will be used to assess the likely impact on ED crowding.DiscussionTo date the efficacy, cost-effectiveness and safety of alternative community-based models of emergency care have not been rigorously investigated. This study will inform the development of ECP protocols through the identification of types of patient presentation that can be considered both safe and appropriate for paramedics to manage in the community.

The ability of early warning scores (EWS) to detect critical illness in the prehospital setting: A systematic review☆

AIM To examine whether early warning scores (EWS) can accurately predict critical illness in the prehospital setting and affect patient outcomes. METHODS We searched bibliographic databases for comparative studies that examined prehospital EWS for patients transported by ambulance in the prehospital setting. The ability of the different EWS, including pre-alert protocols and physiological-based EWS, to predict critical illness (sensitivity, odds ratio [OR], area under receiver operating characteristic [AUROC] curves) and hospital mortality was summarised. Study quality was assessed using the Newcastle-Ottawa Scale. RESULTS Eight studies were identified. Two studies compared the use of EWS to standard practice using clinical judgement alone to identify critical illness: the pooled diagnostic OR and summary AUROC for EWS were 10.9 (95%CI 4.2-27.9) and 0.78 (95%CI 0.74-0.82), respectively. A study of 144,913 patients reported age and physiological variables predictive of critical illness: AUROC in the independent validation sample was 0.77, 95% CI 0.76-0.78. The high-risk patients stratified by the national early warning score (NEWS) were significantly associated with a higher risk of both mortality and intensive care admission. Data on comparing between different EWS were limited; the Prehospital Early Sepsis Detection (PRESEP) score predicted occurrence of sepsis better than the Modified EWS (AUROC 0.93 versus 0.77, respectively). CONCLUSION EWS in the prehospital setting appeared useful in predicting clinically important outcomes, but the significant heterogeneity between different EWS suggests that these positive promising findings may not be generalisable. Adequately powered prospective studies are needed to identify the EWS best suited to the prehospital setting.

Trends in traumatic out-of-hospital cardiac arrest in Perth, Western Australia from 1997 to 2014

AIM This study aims to describe and compare traumatic and medical out-of-hospital cardiac arrest (OHCA) occurring in Perth, Western Australia, between 1997 and 2014. METHODS The St John Ambulance Western Australia (SJA-WA) OHCA Database was used to identify all adult (≥ 16 years) cases. We calculated annual crude and age-sex standardised incidence rates (ASIRs) for traumatic and medical OHCA and investigated trends over time. RESULTS Over the study period, SJA-WA attended 1,354 traumatic OHCA and 16,076 medical OHCA cases. The mean annual crude incidence rate of traumatic OHCA in adults attended by SJA-WA was 6.0 per 100,000 (73.9 per 100,000 for medical cases), with the majority resulting from motor vehicle collisions (56.7%). We noted no change to either incidence or mechanism of injury over the study period (p>0.05). Compared to medical OHCA, traumatic OHCA cases were less likely to receive bystander cardiopulmonary resuscitation (CPR) (20.4% vs. 24.5%, p=0.001) or have resuscitation commenced by paramedics (38.9% vs. 44.8%, p<0.001). However, rates of bystander CPR and resuscitation commenced by paramedics increased significantly over time in traumatic OHCA (p<0.001). In cases where resuscitation was commenced by paramedics there was no difference in the proportion who died at the scene (37.2% traumatic vs. 34.3% medical, p=0.17), however, fewer traumatic OHCAs survived to hospital discharge (1.7% vs. 8.7%, p<0.001). CONCLUSIONS Despite temporal increases in rates of bystander CPR and paramedic resuscitation, traumatic OHCA survival remains poor with only nine patients surviving from traumatic OHCA over the 18-year period.

Is it Appropriate for Patients to be Discharged at the Scene by Paramedics

Abstract Background: Outcomes of patients who are discharged at the scene by paramedics are not fully understood. Objective: We aimed to describe the risk of re-presentation and/or death in prehospital patients discharged at the scene. Methods: We conducted a retrospective cohort study using linked ambulance, emergency department (ED), and death data. We compared outcomes in patients who were discharged at the scene by paramedics with those who were transported to ED by paramedics and then discharged from ED between January 1 and December 31, 2013 in metropolitan Perth, Western Australia. Occurrences of subsequent ambulance requests, ED attendance, hospital admission and death were compared between those discharged at the scene and those discharged from ED. Results: There were 47,330 patients during the study period, of whom 19,732 and 27,598 patients were discharged at the scene and from ED, respectively. Compared to those discharged from ED, those discharged at the scene were more likely to subsequently: request an ambulance (6.1% vs. 1.8%, adjusted odds ratio [adj OR] 3.4; 95% confidence interval [CI] 3.0–3.9), attend ED (4.6% vs. 1.4%, adj OR 3.3; 95% CI 2.8–3.8), be admitted to hospital (3.3% vs. 0.8%, adj OR 4.2; 95% CI 3.4–5.1). Those discharged at the scene tended towards an increased likelihood of death (0.2% vs. 0.1%, adj OR 1.8; 95% CI 0.99–3.2) within 24 hours of discharge compared to those discharged from ED. Conclusion: Patients attended by paramedics who were discharged at the scene had more subsequent events than those who were transported to and discharged from ED. Further consideration needs to be given to who is suitable to be discharged at the scene by paramedics.