In the emergency system of ASL Toscana sud-est, a point-of-care analyzer is present on every advanced vehicle: physician-staffed rapid response vehicles and nurse-staffed ambulances. A complete blood gas analysis (pH, lactate, electrolytes, base excess, hemoglobin) is available in the field, before the patient sees a hospital, in 90 seconds.
This is not an experimental trial. It is daily operations across an entire provincial territory, with an organizational feature that would be difficult to imagine elsewhere: the test is not only performed by the physician. It is also performed by the nurse, on the vehicle, and the result is discussed in real time with the physician at the Operations Center to decide together on treatment and destination.
Antoine Belperio is a paramedic with the 118 emergency service in Arezzo, first author of the poster "Implementation of Point-of-Care Blood Gas Analysis in the COES Arezzo Prehospital Emergency System: Development of an Operational Protocol", presented at the [XIV SIMEU National Congress](LINK) in Naples (May 8-10, 2026, ID 053), together with S. Montemerani, A. Stocchi and M. Gennai [complete names and affiliations to be confirmed].
I asked him to tell us what a blood gas analyzer does in the hands of a crew in the field, when it really changes decisions, and what his team has built to standardize its use.
1. What a Blood Gas Analyzer Does in the Field
Antoine, let's start with the essentials. For those who don't work in prehospital care, why is a blood gas analysis in the field different from one done in the Emergency Department twenty minutes later?
POC blood gas analysis provides immediate decision support for the critical patient, allowing targeted therapy to be initiated directly on scene and guiding centralization to the most appropriate hospital facilities.
Looking at the data, although respiratory failure represents the main area (40%), over 60% of applications involve non-respiratory pathologies: major trauma (18%), cardiac arrest and post-ROSC (15%), sepsis and shock (12%), coma and altered consciousness (8-10%), dialysis emergencies and electrolyte disorders (5%), other (2.5%).
A methodological clarification: these percentages are calculated on the subsample of tests correctly recorded in the management system and attributable to a specific clinical indication, reconstructed from the subcategories of the pathology code.
The Operational Instruction identifies the main areas of application as major trauma, respiratory failure, sepsis, dialysis emergencies, cardiac arrest, coma, and electrocardiographic alterations related to electrolyte imbalances.
2. How Often It Changes a Decision
The literature has validated the feasibility and accuracy of prehospital POCT, but has not yet demonstrated an outcome benefit. In your field experience, how often does the blood gas result really change a decision? And does the Operational Instruction now put you in a position to measure it?
In field practice, the blood gas analysis result can substantially modify the patient's pathway, both regarding immediate treatment and the choice of destination hospital.
An example: the patient with suspected diabetic ketoacidosis. Without blood gas data, the decision between transport to a spoke hospital ten minutes away and centralization to a hub thirty minutes away may be based primarily on clinical assessment. The availability of objective parameters (pH, bicarbonates, lactate, glucose, electrolytes) instead allows quantification of the severity of the metabolic alteration and supports a more appropriate choice. Diabetic ketoacidosis is included among the possible causes of metabolic acidosis detectable in patients with altered mental status.
The same principle applies in other scenarios: in respiratory failure, blood gas analysis can guide the choice between CPAP and BiPAP; in sepsis, the lactate value can determine pre-alert and activation of the dedicated pathway; in major trauma, pH, lactate and base excess can support early activation of the massive transfusion protocol; in dialysis patients, the result may necessitate centralization to a facility with 24-hour dialysis availability; in cardiac arrest, it can contribute to identifying reversible causes.
Saying that blood gas analysis "changes the patient's fate" expresses operational experience, but from a scientific standpoint it is more correct to state that it can modify the decision-making process and care pathway. At present, we do not have a systematic measurement of how often this occurs.
The Operational Instruction can create the conditions to measure it, provided that prospective data collection records the clinical decision planned before the blood gas analysis, the test result, any modification of treatment, any modification of destination, pre-alert or activation of a specific pathway, and centralization times. This way it will be possible to move from clinical perception of usefulness to a measurable indicator of decision-making impact.
3. The Nursing Model and the Operations Center
There's one fact that struck me: nurse-staffed ambulances maintain stable volumes over two years (95 and 95), while physician-staffed vehicles drop from 184 to 162. For an international reader, a paramedic who performs and interprets a blood gas analysis in the field is an uncommon scenario. How does this model work?
The reduction in tests attributed to Alpha units, from 184 in 2024 to 162 in 2025, does not indicate a lower propensity of physicians to use blood gas analysis. It is mainly related to a remodeling of territorial coverage, with a different distribution of operational configuration between physician-staffed vehicles and nurse-staffed ambulances. The difference between the two years must therefore be interpreted in light of actual operational hours and different resource distribution, not only by comparing absolute numbers.
In the current organizational model, the nurse can decide to perform blood gas analysis based on the patient's clinical condition or on indication from the physician at the Operations Center. The result is then transmitted to the Operations Center and discussed with the physician, with whom treatment and the most appropriate hospital destination are agreed upon.
This is therefore not a completely autonomous and isolated process, but an advanced nursing model integrated with supervision and remote decision support from the Operations Center. The Operational Instruction itself defines POC blood gas analysis as a tool intended for both medical personnel and advanced nursing personnel, used in the decision-making process in collaboration with the Operations Center.
4. Feasibility and Technical Limitations
Managing an analyzer aboard a moving vehicle presents different challenges from a hospital laboratory. From temperature fluctuations to calibration to quality controls: what are the main critical issues and how are they managed?
The Operational Instruction directly addresses the critical nodes of feasibility and timing, considering workloads and operational conditions. Technical times are standardized: instrument calibration in 160-180 seconds and analytical response in 90 seconds, with operating temperatures between 10°C and 35°C.
The most critical aspects in daily use concern cartridge storage, compliance with operating temperatures, temperature fluctuations inside the vehicle, quality controls, and operator training. Added to these are correct patient identification, sample quality, risk of hemolysis or contamination, and the need to correctly record and transmit the result.
The clinical utility of the data depends on its analytical reliability: a result obtained quickly but under inadequate preanalytical or operational conditions can lead to inappropriate decisions. The Operational Instruction was also created to ensure diagnostic accuracy and safety in prehospital use of the instrument.
A central point is network integration: immediate communication of blood gas parameters to the Operations Center allows the destination hospital to be alerted before the patient's arrival, anticipating activation of dedicated pathways.
5. The Role of Technology Partners
A crucial aspect for the functioning of such a complex POCT network is technological support and device management. What role can collaboration with industry and technology partners play in implementing and managing such an articulated model?
Collaboration with qualified technology partners represents a fundamental element for the implementation and sustainability of such a widespread and complex POCT network.
In our case, within the current rental supply arrangement, collaboration with Siemens Healthineers has represented important technological support for the development and management of the project.
Managing Point-of-Care analyzers installed aboard moving emergency vehicles (physician-staffed vehicles and nurse-staffed ambulances) presents unique challenges, related to temperature fluctuations and the need for constant and rapid calibrations, such as the 160-180 seconds required by our protocol.
Thanks to technological solutions and support from Siemens, we have been able to ensure that each device strictly meets the quality and diagnostic accuracy requirements demanded. This scientific-technological partnership has allowed effective integration of analytical systems with our IT network, making real-time data traceability possible and effectively validating the reliability of the entire framework of our new Operational Instruction.
6. The Gap That Started Everything
So far we've talked about what blood gas analysis can do in the field. Let's come to the problem that gave rise to your work. Under-registration at 58% in 2024 and 68% in 2025, therefore worsening. How did this data emerge?
The need for this work arose from objective data that emerged from our gap analysis: systematic under-registration of point-of-care blood gas tests that reached 58% in 2024 and 68% in 2025.
We were facing a paradox: POC blood gas analysis was being used in the field to guide therapy for critical patients, but more than half of this clinical data was not being tracked at the administrative and IT level. There was a need to fill this void and build a standardized procedure.
The total number of tests actually performed is what emerges from comparing two sources: 279 tests in 2024 (of which 184 attributed to Alpha physician-staffed vehicles and 95 to India nurse-staffed ambulances) and 257 in 2025 (162 Alpha and 95 India). The registration gap represents the difference between these tests, obtained directly from the analyzer memory, and those correctly entered in the Operations Center management system.
7. How to Reconstruct Data That Doesn't Exist
If under-registration is the problem, how did you reconstruct the denominator of tests actually performed? This is a question I think anyone reading the poster will ask.
The denominator was reconstructed through direct download of tests stored in the EPOC analyzers present on emergency vehicles.
Data downloaded from the instruments were subsequently compared with tests present in the Operations Center management system. This made it possible to distinguish tests actually performed in the field, those correctly recorded in the management system, and those performed but not recorded.
Under-registration therefore derives from a comparison between two different sources: on one hand the instrumental data, considered as a reference for activity actually performed, and on the other hand the administrative-clinical data present in the management system.
There is also an organizational peculiarity to make explicit: in two stations the same EPOC analyzer is used during the day by the India nurse-staffed ambulance and at night by the Alpha physician-staffed vehicle. To make the analysis uniform, these stations were conventionally considered as Alpha units operating 24 hours. This methodological choice may influence the distribution of tests between the two types of vehicles, while not modifying the overall total.
8. Building the Protocol
The work is co-authored with Montemerani, Stocchi and Gennai, who work in different services: COES, the Emergency Department of San Donato Hospital, Pegaso 2 helicopter emergency service. How did you build the procedure together?
Our different affiliations, between the COES Arezzo Unit, the Emergency Medicine and Surgery Unit of San Donato Hospital, and the Pegaso 2 Helicopter Emergency Service Unit in Grosseto, allowed us to combine complementary skills. This enabled us to analyze the problem from multiple perspectives: from logistical management on the emergency vehicle to continuity of care in the Emergency Department. Discussing and validating together every step of the new Operational Instruction ensured that the protocol was not only theoretical, but sustainable and applicable in the reality of prehospital emergency care.
9. Volumes and Variability
Your system performs about 280 blood gas analyses per year across the entire territory, physician-staffed vehicles and nurse-staffed ambulances combined. The technology is distributed widely, but use remains selective. Is this the appropriate volume, or alongside under-registration is there also an issue of underutilization?
Alongside under-registration there probably also exists an issue of variability in instrument use.
Currently the decision to perform blood gas analysis depends largely on the assessment of the healthcare provider present on scene. This makes use highly operator-dependent: faced with similar clinical conditions, different professionals may decide differently whether or not to perform the test.
The observed volume therefore cannot be automatically interpreted as either appropriate or insufficient. Rather, the work shows that, in the absence of shared indications, it is not possible to establish with certainty whether blood gas analysis was correctly reserved for critical patients or was omitted in some potentially eligible cases.
This second gap, relating to appropriateness and uniformity of use, was one of the main reasons for creating the Operational Instruction. The document defines clinical conditions, threshold values, and care pathways in which the test may be indicated. POC blood gas analysis is available on all ALS and nurse-staffed vehicles of COES Arezzo and is intended for highly critical clinical conditions.
The goal is not to indiscriminately increase the number of tests, but to ensure that patients with similar clinical characteristics receive the same assessment, regardless of the professional or vehicle that responded.
Antoine Belperio is a paramedic with the 118 emergency service in Arezzo (COES Unit, ASL Toscana sud-est), with approximately ten years of experience in emergency care. He divides his time between field emergency services, mass casualty incident management, and activity as an instructor, both for specialty courses and in the university setting. He pursues research projects related to the introduction of new technologies to improve care in the field.
https://www.linkedin.com/in/antoine-belperio/
Poster: Belperio A, Montemerani S, Stocchi A, Gennai M. "Implementation of Point-of-Care Blood Gas Analysis in the COES Arezzo Prehospital Emergency System: Development of an Operational Protocol." XIV SIMEU National Congress, Naples, May 8-10, 2026. ID 053.
The Operational Instruction is currently under approval within the Operations Center protocol review process initiated in preparation for accreditation.
Disclosure: the POCT analyzers supplied to COES Arezzo are provided on rental by Siemens Healthineers.
