The impact of the patient's initial NACA score on subjective and physiological indicators of workload during pre-hospital emergency care

Identifying and validating perceived workload metrics for emergency medical services

The most common workload surrogates used by Emergency Medical Services (EMS)- overall call volume (CV) and unit hour utilization (UHU)-have not been validated. This study investigates the relationship between EMS operational metrics and perceived workload, measured through the NASA task load index (TLX) survey. We paired crew member survey responses with the operational metrics based on dispatch data. Linear regression was used to evaluate the influence of each metric on perceived workload. Logistic regression was used to identify values of workload indicating a fair day's work. We found that the overall CV (p < 0.001, R2=0.32) and UHU (p < 0.001, R2=0.22) explained less variability in perceived workload than a priority (P)-stratified CV (p < 0.001, R2=0.41). However, we found no clear fair day's workload threshold. We conclude that a priority-stratified CV is a better workload surrogate than a CV and UHU.

Understanding The Role of Cognitive Load In Paramedical Contexts: A Systematic Review

Objectives: Cognitive load refers to the working memory resources required during a task. When the load is too high or too low this has implications for an individual's task performance. In the context of paramedicine and emergency medical services (EMS) broadly, high cognitive load could potentially put patient and personnel safety at risk. This systematic review aimed to determine the current understanding of the role of cognitive load in paramedical contexts.Methods: To do this, five databases were searched (Elsevier Embase, ProQuest Psychology, CINAHL, Ovid Medline, and Ovid PsychINFO) using synonyms of cognitive load and paramedical contexts. Included articles were full text, peer reviewed empirical research, with a focus on cognitive load and EMS work. Two reviewers screened titles, abstracts, and full text using a traffic light system against the inclusion and exclusion criteria. The quality of evidence was assessed using the GRADE framework. This study was registered on PROSPERO (CRD42022384246). No funding was received for this research.Results: The searches identified 73 unique articles and after title/abstract and full text screening, 25 articles were included in the final review. Synthesis of the research revealed 10 categories of findings in the area. These are clinical performance, cognitive processes, emotional responses, physical expenditure, physiological responses, equipment and ergonomics, expertise and experience, multiple loads, cognitive load measures, and task complexity.Conclusions: From these findings it was determined that there is agreement in terms of what factors influence cognitive load in paramedical contexts, such as cognitive processes, task complexity, physical expenditure, level of experience, multiple types of loads, and the use of equipment. Cognitive load influences clinical task performance and has a bi-directional relationship with emotion. However, the literature is mixed regarding physiological responses to cognitive load, and how they are best measured. These findings highlight potential intervention points where cognitive load can be managed or reduced to improve working conditions for EMS clinicians and safety for their patients.

Use of bitemporal NACA score documentation in prehospital emergency medical services- a retrospective study

BACKGROUND

The assessment of illness severity in the prehospital setting is essential for guiding appropriate medical interventions. The National Advisory Committee for Aeronautics (NACA) score is a validated tool commonly used for this purpose. However, the potential benefits of using bitemporal documentation of NACA scores to capture the dynamic changes in emergency situations remain uncertain. The objective of this study was to evaluate the potential benefit of bitemporal NACA score documentation in the prehospital setting, specifically in assessing the dynamic changes of emergencies and facilitating quality improvement through enhanced documentation practices.

METHODS

In this retrospective study, data from prehospital emergency patients were analyzed who received care from the physician response unit between January 1, 2018, and May 31, 2021. Patient demographics, NACA scores, indications for emergency care, and changes in NACA scores were extracted from medical records. Statistical analyses were performed to examine the associations between NACA scores, emergency categories, indications, and changes in NACA scores.

RESULTS

The study included 4005 patients, predominantly categorized as NACA III (33.7% at initial assessment, 41.8% at subsequent assessment) and NACA IV (31.6% at initial assessment, 22.4% at subsequent assessment). There was a significant improvement in NACA scores during the provision of prehospital care (p < 0.01). Notably, prehospital emergencies attributed to internal medical, neurological, traumatic, and paediatric causes demonstrated significant improvements in NACA scores (p < 0.01). Gender-specific differences were also observed.

CONCLUSION

Our study suggests that the bitemporal documentation of NACA scores can be advantageous in the prehospital setting and may have implications for research, practice, and policy.

Prevalence and severity of pediatric emergencies in a German helicopter emergency service: implications for training and service configuration

This study primarily aims to determine the frequency of life-threatening conditions among pediatric patients served by the DRF, a German helicopter emergency service (HEMS) provider. It also seeks to explore the necessity of invasive procedures in this population, discussing the implications for HEMS crew training and service configuration based on current literature. We analyzed the mission registry from 31 DRF helicopter bases in Germany, focusing on 7954 children aged 10 or younger over a 5-year period (2014-2018). Out of 7954 identified children (6.2% of all primary missions), 2081 (26.2%) had critical conditions. Endotracheal intubation was needed in 6.5% of cases, while alternative airway management methods were rare (n = 14). Half of the children required intravenous access, and 3.6% needed intraosseous access. Thoracostomy thoracentesis and sonography were only performed in isolated cases.  Conclusions: Critically ill or injured children are infrequent in German HEMS operations. Our findings suggest that the likelihood of HEMS teams encountering such cases is remarkably low. Besides endotracheal intubation, life-saving invasive procedures are seldom necessary. Consequently, we conclude that on-the-job training and mission experience alone are insufficient for acquiring and maintaining the competencies needed to care for critically ill or injured children. What is Known: • Pediatric emergencies are relatively rare in the prehospital setting, but their incidence is higher in helicopter emergency medical services (HEMS) compared to ground-based emergency services. What is New: • On average, HEMS doctors in Germany encounter a critically ill or injured child approximately every 1.5 years in their practice, establish an IV or IO access in infants or toddlers every 2 years, and intubate an infant every 46 years. • This low frequency highlights the insufficiency of on-the-job training alone to develop and maintain pediatric skills among HEMS crews. Specific interdisciplinary training for HEMS crews is needed to ensure effective care for critically unwell pediatric patients.

Can video communication in the emergency medical communication centre improve dispatch precision? A before-after study in Norwegian helicopter emergency medical services

OBJECTIVES

Dispatching helicopter emergency medical services (HEMS) to the patients with the greatest medical or logistical benefit remains challenging. The introduction of video calls (VC) in the emergency medical communication centres (EMCC) could provide additional information for EMCC operators and HEMS physicians when assessing the need for HEMS dispatch. The aim of this study was to evaluate the impact from VC in the EMCC on HEMS dispatch precision.

DESIGN

An observational before-after study.

SETTING

The regional EMCC and one HEMS base in Mid-Norway.

PARTICIPANTS

EMCC operators and HEMS physicians at the EMCC and HEMS base in Trondheim, Norway.

INTERVENTION

In January 2022, VC became available in emergency calls in Trondheim EMCC. Data were collected from 2020 2021 (pre-intervention) and 2022 (post-intervention).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the proportion of seriously ill or injured HEMS patients, defined as a National Advisory Committee for Aeronautics (NACA) score between 4 and 7. The secondary outcome was the proportion of inappropriate dispatches, defined as missions with neither provision of additional competence nor any logistical contribution based on quality indicators for physician-staffed emergency medical services.

RESULTS

811 and 402 HEMS missions with patient contact were included in the pre- and post-intervention group, respectively. The proportion of missions with NACA 4-7 was not significantly changed after the intervention (OR 1.21, 95% CI 0.92 to 1.61, p=0.17). There was no significant change in HEMS alarm times between the pre- and post-intervention groups (7.6 min vs 6.4 min, p=0.15). The proportion of missions with neither medical nor logistical benefit was significantly lower in the post-intervention group (28.4% vs 40.3%, p=0.007).

CONCLUSION

The results from this study indicate that VC is a promising, feasible and safe tool for EMCC operators in the complex HEMS dispatch process.

Assessing the Value of Multimodal Interfaces: A Study on Human-Machine Interaction in Weld Inspection Workstations

Multimodal user interfaces promise natural and intuitive human-machine interactions. However, is the extra effort for the development of a complex multisensor system justified, or can users also be satisfied with only one input modality? This study investigates interactions in an industrial weld inspection workstation. Three unimodal interfaces, including spatial interaction with buttons augmented on a workpiece or a worktable, and speech commands, were tested individually and in a multimodal combination. Within the unimodal conditions, users preferred the augmented worktable, but overall, the interindividual usage of all input technologies in the multimodal condition was ranked best. Our findings indicate that the implementation and the use of multiple input modalities is valuable and that it is difficult to predict the usability of individual input modalities for complex systems.

Workflow interruption and nurses' mental workload in electronic health record tasks: An observational study

BACKGROUND

Workflow interruptions are common in modern work systems. Electronic health record (EHR) tasks are typical tasks involving human-machine interactions in nursing care, but few studies have examined interruptions and nurses' mental workload in the tasks. Therefore, this study aims to investigate how frequent interruptions and multilevel factors affect nurses' mental workload and performance in EHR tasks.

METHODS

A prospective observational study was conducted in a tertiary hospital providing specialist and sub-specialist care from June 1^st to October 31^st, 2021. An observer documented nurses' EHR task interruptions, reactions and performance (errors and near errors) during one-shift observation sessions. Questionnaires were administered at the end of the electronic health record task observation to measure nurses' mental workload for the electronic health record tasks, task difficulty, system usability, professional experience, professional competency, and self-efficacy. Path analysis was used to test a hypothetical model.

RESULTS

In 145 shift observations, 2871 interruptions occurred, and the mean task duration was 84.69 (SD 56.68) minutes per shift. The incidence of error or near error was 158, while 68.35% of errors were self-corrected. The total mean mental workload level was 44.57 (SD 14.08). A path analysis model with adequate fit indices is presented. There was a relationship among concurrent multitasking, task switching and task time. Task time, task difficulty and system usability had direct effects on mental workload. Task performance was influenced by mental workload and professional title. Negative affect mediated the path from task performance to mental workload.

CONCLUSIONS

Nursing interruptions occur frequently in EHR tasks, come from different sources and may lead to elevated mental workload and negative outcomes. By exploring the variables related to mental workload and performance, we offer a new perspective on quality improvement strategies. Reducing harmful interruptions to decrease task time can avoid negative outcomes. Training nurses to cope with interruptions and improve competency in EHR implementation and task operation has the potential to decrease nurses' mental workload and improve task performance. Moreover, improving system usability is beneficial to nurses to mitigate mental workload.

Paramedic Student Clinical Performance During High-Fidelity Simulation After a Physically Demanding Occupational Task: A Pilot Randomized Crossover Trial

INTRODUCTION

Paramedic duties include assessing, treating, and maneuvering patients in physically challenging environments. Whether clinical skills and patient care are affected by these occupational demands is unknown. High-fidelity simulation affords the opportunity to study this in a controlled setting.

METHODS

Using a randomized crossover design, 11 regional paramedicine students and graduates (mean ± SD age = 23 ± 2 years) completed two, 20-minute high-fidelity simulations that included cardiopulmonary resuscitation (CPR) immediately after either an acute bout of occupational physical activity (OPA) or a rest period (REST). Heart rate, respiratory rate, and mean arterial pressure were measured throughout. Clinical performance was scored using the Global Rating Score and a patient care record. Measures of CPR efficacy were recorded in the manikin.

RESULTS

There were no significant differences in Global Rating Score ( P = 0.07, ES = 0.03) or CPR efficacy between conditions. Patient care record accuracy was higher after the OPA versus REST simulations (mean ± SD = 61.8 ± 12.6% vs. 55.5 ± 12.0%, P = 0.03, ES = 0.5). Mean heart rate was higher during OPA simulations versus REST simulations (121 ± 14 vs. 84 ± 9 beats per minute, P < 0.01, ES = 3.1), as was mean respiratory rate (19 ± 3 vs. 16 ± 3 breaths per minute, P < 0.01, ES = 1.0). Mean arterial pressure was higher for OPA versus REST at simulation start (105 ± 11.3 vs. 95.8 ± 11.8 mm Hg, P = 0.01, Effect Size = 0.8), although not different after simulation.

CONCLUSIONS

Paramedicine students including recent graduates performed as well, or better, in a simulated clinical scenario immediately after occupation-specific acute physical exertion compared with a REST, despite higher physiological exertion. Whether this is the case for more experienced but potentially less physically fit paramedics in the workforce warrants investigation.

Interhospital transport of critically ill patients: A prospective observational study of patient and transport characteristics

BACKGROUND

The cohort of critically ill patients transported between Intensive Care Units (ICUs) in Norway has not been studied previously. The aim of this study was to describe the characteristics of patients and transports for different types of interhospital transfers and explore whether there were differences in morbidity and mortality between the different transfer categories and the general Norwegian ICU population.

METHODS

All transports of critically ill adult patients transferred between two geographically different Intensive Care Units during a one-year period were registered. Patient and transport data were obtained from The Norwegian Intensive Care Registry, The Norwegian Cause of Death Registry, the hospital Electronic Patient Journal, the Air Ambulance Journal System, and the Emergency Medical Communication Centre database.

RESULTS

821 transports of 788 surgical and medical patients were enrolled. Simplified Acute Physiology Scores (SAPSII) were 43, 36 and 38 for urgent secondary transport, non-urgent secondary transport and return transfers, respectively. These were comparable to nationwide SAPSII scores that were 40 for university hospitals and 34 for local hospitals during the same time period. The return transfers had a median SOFA-score of 4.7 and 53% were mechanically ventilated. Only 33% of return transfers were performed by established teams.

CONCLUSION

Intensive care patients transferred between ICUs are as critically ill as the rest of the ICU population, with a similar morbidity and mortality. The return transfers of ICU-patients appear under-triaged compared to secondary transports in terms of allocated resources.

Simulation Training in Neuroangiography-Validation and Effectiveness

Purpose

Simulators are increasingly used in the training of endovascular procedures; however, for the use of the Mentice vascular interventional system trainer (VIST) simulator in neuroradiology, the validity of the method has not yet been proven. The study was carried out to test the construct validity of such a simulator by demonstrating differences between beginner and expert neurointerventionalists and to evaluate whether a training effect can be demonstrated in repeated cases for different levels of experience.

Methods

In this study 4 experts and 6 beginners performed 10 diagnostic angiographies on the VIST simulator (Mentice AB, Gothenburg, Sweden). Of the cases four were non-recurring, whereas three were repeated once and ten subjects performed all tasks. Additionally, another expert performed only five non-recurring cases. The simulator recorded total time, fluoroscopy time, amount of contrast medium and number of material changes. Furthermore, gaze direction and heart rate were recorded, and subjects completed a questionnaire on workload.

Results

Beginners and experts showed significant differences in total duration time, fluoroscopy time and amount of contrast agent (all p < 0.05). Gaze direction, dwell time and heart rate were similar between both groups. Only beginners improved during training with respect to total duration time, fluoroscopy time and amount of contrast agent. If a case was previously known to them, the total duration and fluoroscopy time were significantly shortened (p < 0.001).

Conclusion

This study demonstrated both the construct validity of a diagnostic neuroangiography simulator as well as a significant training effect for beginners. Therefore, in particular beginner neurointerventionalists should use such simulation tools more extensively in their initial training.

The NACA score as a predictor of ventricular cardiac arrhythmias - A retrospective six-year study

BACKGROUND

Helicopter Emergency Medical Service (HEMS) conducts the evaluation of a patient's condition using NACA score before transporting the patient to hospital. The conditions inside the rescue helicopter limit or even make it impossible to conduct some medical procedures. An appropriate classification of the patient may lead to a lower possibility of occurrence of adverse events during the flight. The aim of the research was to evaluate the correlation of NACA score with the cardiac arrhythmia that may be life threatening.

METHODS

A retrospective observational study included a group of 47,131 patients, who were transported by HEMS services between 2012 and 2017. The research was conducted using the analysis of variance ANOVA running a post hoc test. In order to calculate the correlation of variables, Kruskal-Wallis and r-Pearson tests were carried out, interpreting the results according to J. Gilville's scale. The significance level was set at α = 0,05.

RESULTS

The average number of points using NACA score for the studied group was 4,06 (SD ± 1,38). Twelve heart rhythms were selected while evaluating correlations using NACA score. There was a significant relation between the ECG variable and NACA score (p = 0,003). There was a very strong correlation between NACA score and the following: VF/pVT (r-Pearson = 0,856; p = 0,006), PEA (r-Pearson = 0,810; p = 0,015) and Asystole (r-Pearson = 0,728; p = 0,026).

CONCLUSIONS

NACA score allows to predict the risk of occurrence of ventricular arrhythmia of the myocardium as well as cardiac arrest. The possibility of occurrence of a life-threatening rhythm is significantly higher in patients classified as NACA IV or higher.

Workload and influencing factors in non-emergency medical transfers: a multiple linear regression analysis of a cross-sectional questionnaire study

Background

Human workload is a key factor for system performance, but data on emergency medical services (EMS) are scarce. We investigated paramedics’ workload and the influencing factors for non-emergency medical transfers. These missions make up a major part of EMS activities in Germany and are growing steadily in number.

Methods

Paramedics rated missions retrospectively through an online questionnaire. We used the NASA-Task Load Index (TLX) to quantify workload and asked about a variety of medical and procedural aspects for each mission. Teamwork was assessed by the Weller teamwork measurement tool (TMT). With a multiple linear regression model, we identified a set of factors leading to relevant increases or decreases in workload.

Results

A total of 194 non-emergency missions were analysed. Global workload was rated low (Mean = 27/100). In summary, 42.8% of missions were rated with a TLX under 20/100. TLX subscales revealed low task demands but a very positive self-perception of performance (Mean = 15/100). Teamwork gained high ratings (Mean TMT = 5.8/7), and good teamwork led to decreases in workload. Aggression events originating from patients and bystanders occurred frequently (n = 25, 12.9%) and increased workload significantly. Other factors affecting workload were the patient’s body weight and the transfer of patients with transmittable pathogens.

Conclusion

The workload during non-emergency medical transfers was low to very low, but performance perception was very positive, and no indicators of task underload were found. We identified several factors that led to workload increases. Future measures should attempt to better train paramedics for aggression incidents, to explore the usefulness of further technical aids in the transfer of obese patients and to reconsider standard operating procedures for missions with transmittable pathogens.

Single mission workload and influencing factors in German prehospital emergency medicine - a nationwide prospective survey of 1361emergency missions

Background

Workload is a major determinant of system performance and human well-being. This study aims to evaluate workload in prehospital emergency medicine on a single mission level and investigates influencing factors originating from medical scenarios, patient-provider interaction, EMS logistics and teamwork.

Methods

In a nationwide study, German paramedics were asked to evaluate single missions for perceived workload by completing the NASA Task-Load-Index (TLX). A variety of candidate variables were documented and tested for influence on the TLX through multivariate regression analysis.

Results

One thousand three hundred sixty-one emergency missions were analysed. Global workload scored in medium ranges (Median TLX 41.00/100; IQR 24.25–57.50). 263 missions achieved very low (< 20/100) and 52 missions achieved very high (> 80/100) levels of workload. Severity of distress as indicated by the NACA score (delta TLX 2.71 per 1 NACA point), execution of invasive procedures (e.g. delta TLX 8.20 for intravenous access), obese patients (delta TLX 0.05 per 1 kg of weight) and aggression incidences (e.g. delta TLX 10.54 for physical aggression), amongst others, resulted in significant increases in workload. Good teamwork decreased workload by 2.18 points per 1 point on the Weller-Teamwork Measurement Tool.

Conclusion

Distinct factors result in significant increases in workload for EMS paramedics. Improvements in training for certain medical scenarios, strategies against aggression events and enhancements in EMS logistics - especially for the transfer of obese patients – should be implemented and tested for their presumably positive effect on workload, EMS performance and paramedics’ well-being.

Electronic supplementary material

The online version of this article (10.1186/s13049-019-0650-2) contains supplementary material, which is available to authorized users.