Short summary

Sepsis is estimated to affect more than 30 million people globally. 

Detecting sepsis is notoriously difficult and there are no systems in place utilized prehospitally. In Denmark, the Mobile Emergency Care Unit (the MECU), manned by a physician and paramedic, is able to draw blood cultures and take venous lactate measurements before administering antibiotics. 

This study aims to conduct a quality control on the ability of the MECU to recognize and treat sepsis by confirming the amounts of in-hospitally diagnosed cases. Furthermore the study investigates whether the blood cultures falls within an acceptable range of contamination. 

Rationale

Sepsis is a life-threatening condition where a dysregulated host response to infection leads to organ dysfunction and possibly failure. It is estimated that sepsis affects more than 30 million people globally, leading to 6 million deaths, with mortality up to 50% of all diagnosed with septic shock. 

It is known that early recognition of sepsis and treatment thereof is crucial for survival and improvement in outcome, and mortality increases with 3-7.6% with every one hour delay of antibiotic treatment. 

Many studies have found that training in recognition of sepsis by the Emergency Medical Services (EMS) personnel improves time to antibiotics, as the emergency department administer antibiotics earlier than normally upon arrival given the initial prehospital diagnosis has been forwarded as sepsis. A Danish study found that patients with bacterial meningitis diagnosed upon arrival will have a median time to antibiotic therapy of 1,3 hours compared to 8,5 hours when diagnosed after admission. This time difference in diagnosing bacterial meningitis on admission or later, and the subsequent time to antibiotics (TTA) was of significance in in-hospital mortality (14% vs. 30%).

However, some studies have found no significant change in mortality when time to antibiotics was decreased.  A Dutch intervention trial sought to determine whether antibiotics administered prehospitally would have a positive effect on mortality, but found no significant difference in neither mortality, ICU admissions, nor length of admission. Another study done by the EMS in Western Sweden also found that there were no significant associations between mortality and time to antibiotics. 

In Denmark, the EMS consists of not only ambulances operated by paramedics and emergency technicians (EMTs) but also of Mobile Emergency Care Unit (MECU) staffed with an emergency physician with specialist training in anesthesiology and a paramedic. Only the physician on the MECU can administer antibiotics in Denmark; this emphasizes the importance of the first responding emergency unit's capability in detecting and realizing the need for antibiotics in a patient so that the MECU can be requested and treatment initiated quickly. Determination of administering antibiotics is done at the discretion of the attending anaesthesiologist manning the MECU. 

The purpose of administering antibiotics prehospitally is of high importance in prophylaxis of bacteraemia and in TTA when the prehospital tentative diagnosis is infection or risk hereof. 

Blood cultures

Blood cultures (BCs) taken prehospitally is a relevant and important diagnostic tool and aids in bringing time to con- or affirmation of bacteraemia down. Prehospitally and in-hospitally focus on contamination must be kept, as it in one Danish study has been found that 11,6% of all positive BCs contain pathogens considered to be contamination. By far the dominating pathogen has been S. Epidermidis as well as other coagulase-negative staphylococci.

Prehospitally when working in less-than-optimal conditions it is often easiest to draw blood cultures from the peripheral venous catheter as this is being placed. This, however, has proven to be associated with higher contamination rates and might account for growth findings in BCs and potentially lead to unnecessary or incorrect antibiotic treatment. 

At the Department of Clinical Microbiology, Odense University Hospital, the blood culture positivity rate has been approximately 7% to 8% from 2013 to 2017, including contaminants.

The purpose of this retrospective study is to conduct a quality control of the obtaining of blood cultures and of antibiotics given in the prehospital setting by the MECU in Odense in the Region of Southern Denmark in a time interval of 5 years (2013-2018). The primary purpose is to associate the prehospital tentative diagnosis (assigned by the MECU) with the final diagnosis (ICD10 from hospital charts) including: 

1: An indication for antibiotic therapy and 

2: An assessment of the feasibility and potential benefit of the blood cultures obtained. 

3: A description of the bacteria found in the blood cultures.

The association between initial prehospital diagnosis and final the diagnosis will be compared.

Secondly the patients seen by the MECU will be characterized in diagnosis (ICD10), age, sex and the first set of vital parameters (HR, BP, RR, SAT, GCS, TP, ECG). 

Description of the cohort

The cohort is defined as all patients age 18 or older that were given antibiotics prehospitally within the time period of Nov. 1st 2013 to Oct. 31st 2018.

Data and biological material

Register data 

Collaborating researchers and departments

The Prehospital Research Unit, Region of Southern Denmark 

• Consultant Professor Søren Mikkelsen, PhD

Department of Clinical Microbiology, Odense University Hospital

• Associate professor Ulrik, MD, DMSc 

Publications associated with the project

Mikkelsen VS, Gregers MCT, Justesen US, Schierbeck J, Mikkelsen S. Pre-hospital antibiotic therapy preceded by blood cultures in a physician-manned mobile emergency care unit. Acta Anaesthesiol Scand. 2021 Jan 6. doi: 10.1111/aas.13777. Epub ahead of print. PMID: 33405246.