Laboratory testing during critical care transport: point-of-care testing in air ambulances

A review of temperature-related challenges and solutions for the Abbott i-STAT and Siemens Healthineers epoc devices

The Abbott i-STAT and Siemens Healthineers epoc are commonly used in the provision of care during emergency medical services calls and other settings. Maintaining these systems within manufacturer's temperature claims in these settings poses challenges across the world. This review summarizes solutions that have been reported in the peer-reviewed literature and proposes additional strategies to further address these challenges. A literature search was performed with Clarivate's Web of Science from inception to August 3, 2022. Search terms included i-STAT, epoc, temperature, cold, hot, heat, freeze, frozen, prehospital, disaster, POCT, point of care, blood gas, helicopter, airplane, and ambulance. One author also reviewed manually every issue of the Journal of Paramedic Practice. The search identified 17 solutions for addressing temperature-related challenges with the i-STAT device, nine solutions for i-STAT cartridges, one solution for the epoc device, and one solution for the epoc test card. The majority of solutions were highly portable and consisted of widely available, inexpensive components. The solutions demonstrated only partial or entirely questionable effectiveness in achieving temperature control. The search also identified five reports on the impact of storage temperatures on cartridges and test cards. The reports suggested that these reagents may be able to withstand storage at temperatures outside of manufacturer's claims with only minimal deterioration in performance. The heterogeneity of solutions and the paucity of evidence on their effectiveness suggest that additional strategies are needed to better understand and further address temperature-related challenges with these systems. A collaborative approach and shared decision making are recommended.

Implementation and challenges of portable blood gas measurements in air medical transport

OBJECTIVES

Ventilator management in prehospital settings using end-tidal CO₂ can lead to inappropriate ventilation in the absence of point of care blood gas (POCBG) measurements. Implementation of POCBG testing in helicopter Emergency Medical Services (HEMS) is limited in part because of concern for preanalytical and analytical errors due to altitude, vibration, and other associated environmental factors and due to insufficient documentation of implementation challenges.

METHODS

We performed accuracy and precision verification studies using standard materials tested pre-, in-, and post-flight (n=10) in a large HEMS agency. Quality assurance error log data were extracted and summarized for common POCBG errors during the first 31 months of use and air medical transport personnel were surveyed regarding POCBG use (n=63).

RESULTS

No clinically significant differences were found between pre-, in-, and post-flight blood gas measurements. Error log data demonstrated a reduction in device errors over time. Survey participants found troubleshooting device errors and learning new clinical processes to be the largest barriers to implementation. Continued challenges for participants coincided with error log data including temperature and sampling difficulties. Survey participants indicated that POCBG testing improved patient management.

CONCLUSIONS

POCBG testing does not appear to be compromised by the HEMS environment. Temperature excursions can be reduced by use of insulated transport bags with heating and cooling packs. Availability of POCBG results in air medical transport appeared to improve ventilator management, increase recognition of ventilation-perfusion mismatch, and improve patient tolerance of ventilation.

Point-of-Care Testing Practices, Failure Modes, and Risk-Mitigation Strategies in Emergency Medical Services Programs in the Canadian Province of Alberta

CONTEXT.—

Emergency medical services (EMS) programs have been using point-of-care testing (POCT) for more than 20 years. However, only a handful of reports have been published in all of that time on POCT practices in field settings.

OBJECTIVE.—

To provide an overview of POCT practices and failure modes in 3 of Alberta's EMS programs, and to propose risk-mitigation strategies for reducing or eliminating these failure modes.

DESIGN.—

Details about POCT practices, failure modes, and risk-mitigation strategies were gathered through (1) conversations with personnel, (2) in-person tours of EMS bases, (3) accompaniment of EMS personnel on missions, (4) internet searches for publicly available information, and (5) a review of laboratory documents.

RESULTS.—

Practices were most standardized and robust in the community paramedicine program (single service provider, full laboratory oversight), and least standardized and robust in the air ambulance program (4 service providers, limited laboratory oversight). Common failure modes across all 3 programs included device inoperability due to cold weather, analytical validation procedures that failed to consider the unique challenges of EMS settings, and a lack of real-time electronic transmission of results into the health care record.

CONCLUSIONS.—

A provincial framework for POCT in EMS programs is desirable. Such a framework should include appropriate funding models, laboratory oversight of POCT, and relevant expertise on POCT in EMS settings. The framework should also incorporate specific guidance on quality standards that are needed to address the unique challenges of performing POCT in field settings.

Point-of-Care Laboratory Data Collection During Critical Care Transport

OBJECTIVE

Critical care transport involves a high level of intensive clinical care in a resource-limited environment. These patients require multiple assessments guiding specialty treatments, including blood product administration, intravenous electrolyte replacement, ventilator management, and extracorporeal membrane oxygenation. This study aims to measure the usage of point-of-care (POC) laboratory data during critical care transport.

METHODS

Data were collected via electronic medical record review over 1 year of use in a hospital-based critical care rotor wing, fixed wing, and ground critical care transport team in the Southeastern United States.

RESULTS

One hundred twenty POC tests were performed during 1,075 critical care transports over the 1-year period (8.9%). Patient transportations involved 35 extracorporeal membrane oxygenation, 21 medical, 17 cardiac, 13 neonatal, 11 respiratory failure, 8 gastrointestinal bleeding, 6 neurologic, 5 pediatrics, 3 trauma, and 1 organ donor. Seventy-eight POC laboratory tests (65%) required intervention, including ventilator changes (39.7%), electrolyte replacement (35.8%), blood products (7.6%), and other (12.8%). The remaining 42 (35%) POC laboratory tests confirmed no intervention was necessary (n = 35) and that ongoing treatments were effective (n = 7).

CONCLUSION

POC laboratory testing performed during critical care transport guides providers in performing essential emergent interventions in a timelier manner that may benefit critically ill patients.

Geospatial Science and Point-of-Care Testing: Creating Solutions for Population Access, Emergencies, Outbreaks, and Disasters

Objectives: (a) To understand how to integrate geospatial concepts when implementing point-of-care testing (POCT); (b) to facilitate emergency, outbreak, and disaster preparedness and emergency management in healthcare small-world networks; (c) to enhance community resilience by using POCT in tandem with geographic information systems (GISs) and other geospatial tools; and (d) to advance crisis standards of care at points of need, adaptable and scalable for public health practice in limited-resource countries and other global settings.

Content: Visual logistics help integrate and synthesize POCT and geospatial concepts. The resulting geospatial solutions presented here comprise: (1) small-world networks and regional topography; (2) space-time transformation, hubs, and asset mapping; (3) spatial and geospatial care paths™; (4) GIS-POCT; (5) isolation laboratories, diagnostics isolators, and mobile laboratories for highly infectious diseases; (6) alternate care facilities; (7) roaming POCT—airborne, ambulances, space, and wearables; (8) connected and wireless POCT outside hospitals; (9) unmanned aerial vehicles; (10) geospatial practice—demographic care unit resource scoring, geographic risk assessment, and national POCT policy and guidelines; (11) the hybrid laboratory; and (12) point-of-careology.

Value: Small-world networks and their connectivity facilitate efficient and effective placement of POCT for optimal response, rescue, diagnosis, and treatment. Spatial care paths™ speed transport from primary encounters to referral centers bypassing topographic bottlenecks, process gaps, and time-consuming interruptions. Regional GISs position POCT close to where patients live to facilitate rapid triage, decrease therapeutic turnaround time, and conserve economic resources. Geospatial care paths™ encompass demographic and population access features. Timeliness creates value during acute illness, complex crises, and unexpected disasters. Isolation laboratories equipped with POCT help stop outbreaks and safely support critically ill patients with highly infectious diseases. POCT-enabled spatial grids can map sentinel cases and establish geographic limits of epidemics for ring vaccination.

Impact: Geospatial solutions generate inherently optimal and logical placement of POCT conceptually, physically, and temporally as a means to improve crisis response and spatial resilience. If public health professionals, geospatial scientists, and POCT specialists join forces, new collaborative teamwork can create faster response and higher impact during disasters, complex crises, outbreaks, and epidemics, as well as more efficient primary, urgent, and emergency community care.

Diagnosis of acute serious illness: the role of point-of-care technologies

Access to rapid diagnostic information is a core value of point-of-care (POC) technology. This is particularly relevant in acute, emergency, and critical care settings where diagnostic speed and precision directly guide the management of patients with potentially life-threatening conditions. Many POC diagnostics described in the literature, however, remain largely unproven and have yet to enter the market entirely. Only a few have traversed the translation and commercialization pathways to reach widespread clinical adoption. Moreover, even technologies that have successfully translated to the patient bedside still frequently lack an evidence base showing improvement of clinical outcomes. In this review, we present aspects of diagnosis of acute life-threatening diseases and describe the potential role of POC technologies, emphasizing the available evidence of clinical outcomes. Finally, we discuss what is needed to identify clinically meaningful new technologies and translate them toward the long-promised goal of better health through rapid POC diagnosis.

Temperature-sensitive Medications in Interfacility Transport: The Ice Pack Myth

INTRODUCTION

Critical Care Transport teams use various strategies to maintain temperature sensitive drugs and equipment at optimal temperature. The purpose of this study was to examine the effectiveness of current passive refrigeration of temperature sensitive transport medications/equipment.

METHODS

Initially, we performed a retrospective review of transport durations. Subsequently, an experimental paradigm was created using a temperature probe inside of the transport cooler packs utilizing various configurations and initial starting temperatures with high and low "in range" temperature margins of 8°C (max) and 2°C (min).

RESULTS

The mean round-trip transport time was 2.5 hours and over 15% of transports last longer than 4 hours. At a starting temperature of -3.9°C, the cooler and ice pack maintained "in range" temperatures for 3 hours. When the ice pack starting temperature was -12.9°C, high temperatures excursions weren't experienced until 6 hours 55 minutes, but initially low excursions fell below for up to 3 hours. iSTAT^® cartridges remained within range between 1-4 hours at cooler and ice pack starting temperature of -3.9°C.

CONCLUSION

The current system of passive refrigeration does not appear to be sufficient for safely storing medications or point-of-care testing equipment for our transport services. This might reveal a flaw in the existing practices around medication refrigeration in transport.

[Point-of-care testing in preclinical emergency medicine]

BACKGROUND

Measurement of biological signals directly at the patient (point-of-care testing, POCT) is an established standard in emergency medicine when test results are needed quickly and within a reliable time frame or if external testing requires a disproportionate effort.

OBJECTIVES

Currently, the rapid test for β-HCG in urine and POCT measurement of lactate, blood gases, cardiac tropinin, haemoglobin, and hematocrit are well established in emergency medicine. POCT of copeptin, fatty acid-binding proteins (FABP), procalcitonin, coagulation values, natriuretic peptides, D-dimer, and toxicological substances are of future interest. In this article, the appropriate use of point-of-care testing in prehospital emergency medicine is discussed.

RESULTS

Application of POCT is dependent of the underlying conditions, the availability of appropriate devices, and of suitable reference methods in a central laboratory. In addition, economical and quality aspects play an important role.

CONCLUSION

In emergency departments, POCT is currently developing into a standard measuring method for a number of markers because hospital laboratories are increasingly being merged and consequently reduce their emergency-analytic services. In countries with a high density of hospitals, however, preclinical POCT should be reduced to the minimum necessary.

Dynamic Temperature and Humidity Environmental Profiles: Impact for Future Emergency and Disaster Preparedness and Response

Introduction

During disasters and complex emergencies, environmental conditions can adversely affect the performance of point-of-care (POC) testing. Knowledge of these conditions can help device developers and operators understand the significance of temperature and humidity limits necessary for use of POC devices. First responders will benefit from improved performance for on-site decision making.

Objective

To create dynamic temperature and humidity profiles that can be used to assess the environmental robustness of POC devices, reagents, and other resources (eg, drugs), and thereby, to improve preparedness.

Methods

Surface temperature and humidity data from the National Climatic Data Center (Asheville, North Carolina USA) was obtained, median hourly temperature and humidity were calculated, and then mathematically stretched profiles were created to include extreme highs and lows. Profiles were created for: (1) Banda Aceh, Indonesia at the time of the 2004 Tsunami; (2) New Orleans, Louisiana USA just before and after Hurricane Katrina made landfall in 2005; (3) Springfield, Massachusetts USA for an ambulance call during the month of January 2009; (4) Port-au-Prince, Haiti following the 2010 earthquake; (5) Sendai, Japan for the March 2011 earthquake and tsunami with comparison to the colder month of January 2011; (6) New York, New York USA after Hurricane Sandy made landfall in 2012; and (7) a 24-hour rescue from Hawaii USA to the Marshall Islands. Profiles were validated by randomly selecting 10 days and determining if (1) temperature and humidity points fell inside and (2) daily variations were encompassed. Mean kinetic temperatures (MKT) were also assessed for each profile.

Results

Profiles accurately modeled conditions during emergency and disaster events and enclosed 100% of maximum and minimum temperature and humidity points. Daily variations also were represented well with 88.6% (62/70) of temperature readings and 71.1% (54/70) of relative humidity readings falling within diurnal patterns. Days not represented well primarily had continuously high humidity. Mean kinetic temperature was useful for severity ranking.

Conclusions

Simulating temperature and humidity conditions clearly reveals operational challenges encountered during disasters and emergencies. Understanding of environmental stresses and MKT leads to insights regarding operational robustness necessary for safe and accurate use of POC devices and reagents. Rescue personnel should understand these principles before performing POC testing in adverse environments.

FergusonWJ, LouieRF, TangCS, Paw UKT, KostGJ. Dynamic temperature and humidity environmental profiles: impact for future emergency and disaster preparedness and response. Prehosp Disaster Med. 2014;29(1):1-8.

Interchangeability of blood gas, electrolyte and metabolite results measured with point-of-care, blood gas and core laboratory analyzers

BACKGROUND

The random use of point-of-care, blood gas and core laboratory analyzers to measure electrolytes and metabolites increases the variability in test results. This study was designed to determine whether these results performed on whole blood (point-of-care and blood gas) and plasma (core laboratory) platforms are interchangeable without a risk of clinically relevant discrepancies.

METHODS

The interchangeability of the blood gas analysis, electrolytes, glucose, lactate and hemoglobin results performed with three stat platforms (i-STAT, Radiometer ABL 825, RapidLab 865) and two core laboratory platforms (Roche Modular P800 and Sysmex XE-2100) were evaluated using samples from critically ill patients.

RESULTS

For pH, pCO(2), pO(2) and Ca(2+), good correlation (r-values 0.96-1.00) was observed for all comparative analyzers and the biases were within clinically acceptable limits. Potassium, sodium, glucose, lactate and hemoglobin measured with stat analyzers was highly correlated with measurements performed using the laboratory analyzers, r-values 0.89-1.00 and slopes 0.83-1.07. Mean differences with significant bias (p<0.0001) were found for sodium with blood gas analyzers and hemoglobin with i-STAT.

CONCLUSIONS

The blood gas, K(+), Na(+), Ca(2+), glucose and lactate results measured with stat and core laboratory analyzers can be used in different clinical settings for critical care management. However, when monitoring small changes in sodium concentrations, the use of single analyzer is encouraged to avoid analytical differences (acceptance limit ± 2%) and misinterpretation of results measured with multiple analyzers. The users of the i-STAT at low hemoglobin values overdiagnose anaemia. Thus, prior to transfusion, the use of hemoglobin concentrations measured with laboratory analyzers is preferable.