The association between prehospital post-return of spontaneous circulation core temperature and survival after out-of-hospital cardiac arrest.

BACKGROUND AND IMPORTANCE: Following the return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA), a low body temperature on arrival at the hospital and on admission to the ICU is reportedly associated with increased mortality. Whether this association exists in the prehospital setting, however, is unknown. OBJECTIVE: The objective of this study was to investigate whether the initial, prehospital core temperature measured post-ROSC is independently associated with survival to hospital discharge in adult patients following OHCA. DESIGN, SETTING AND PARTICIPANTS: This retrospective observational study was conducted at East Anglian Air Ambulance, a physician-paramedic staffed Helicopter Emergency Medical Service in the East of England, UK. Adult OHCA patients attended by East Anglian Air Ambulance from 1 February 2015 to 30 June 2023, who had post-ROSC oesophageal temperature measurements were included. OUTCOME MEASURE AND ANALYSIS: The primary outcome measure was survival to hospital discharge. Core temperature was defined as the first oesophageal temperature recorded following ROSC. Multivariable logistic regression evaluated the adjusted association between core temperature and survival to hospital discharge. MAIN RESULTS: Resuscitation was attempted in 3990 OHCA patients during the study period, of which 552 patients were included in the final analysis. The mean age was 61 years, and 402 (72.8%) patients were male. Among them, 194 (35.1%) survived to hospital discharge. The mean core temperature was lower in nonsurvivors compared with those who survived hospital discharge; 34.6 and 35.2 °C, respectively (mean difference, -0.66; 95% CI, -0.87 to -0.44; P < 0.001). The adjusted odds ratio for survival was 1.41 (95% CI, 1.09-1.83; P = 0.01) for every 1.0 °C increase in core temperature between 32.5 and 36.9 °C. CONCLUSION: In adult patients with ROSC following OHCA, early prehospital core temperature is independently associated with survival to hospital discharge.

Prehospital invasive arterial blood pressure monitoring in critically ill patients attended by a UK helicopter emergency medical service- a retrospective observational review of practice.

BACKGROUND: Accurate haemodynamic monitoring in the prehospital setting is essential. Non-invasive blood pressure measurement is susceptible to vibration and motion artefact, especially at extremes of hypotension and hypertension: invasive arterial blood pressure (IABP) monitoring is a potential solution. This study describes the largest series to date of cases of IABP monitoring being initiated prehospital. METHODS: This retrospective observational study was conducted at East Anglian Air Ambulance (EAAA), a UK helicopter emergency medical service (HEMS). It included all patients attended by EAAA who underwent arterial catheterisation and initiation of IABP monitoring between 1st February 2015 and 20th April 2023. The following data were retrieved for all patients: sex; age; aetiology (medical cardiac arrest, other medical emergency, trauma); site of arterial cannulation; operator role (doctor/paramedic); time of insertion and, where applicable, times of pre-hospital emergency anaesthesia, and return of spontaneous circulation following cardiac arrest. Descriptive analyses were performed to characterise the sample. RESULTS: 13,556 patients were attended: IABP monitoring was initiated in 1083 (8.0%) cases, with a median age 59 years, of which 70.8% were male. 546 cases were of medical cardiac arrest: in 22.4% of these IABP monitoring was initiated during cardiopulmonary resuscitation. 322 were trauma cases, and the remaining 215 were medical emergencies. The patients were critically unwell: 981 required intubation, of which 789 underwent prehospital emergency anaesthesia; 609 received vasoactive medication. In 424 cases IABP monitoring was instituted en route to hospital. CONCLUSION: This study describes over 1000 cases of prehospital arterial catheterisation and IABP monitoring in a UK HEMS system and has demonstrated feasibility at scale. The high-fidelity of invasive arterial blood pressure monitoring with the additional benefit of arterial blood gas analysis presents an attractive translation of in-hospital critical care to the prehospital setting.

Decision support tool and suggestions for the development of guidelines for the helicopter transport of patients with COVID-19.

The novel coronavirus SARS-CoV2 emerged in December 2019 and is now pandemic. Initial analysis suggests that 5% of infected patients will require critical care, and that respiratory failure requiring intubation is associated with high mortality.Sick patients are geographically dispersed: most patients will remain in situ until they are in need of critical care. Additionally, there are likely to be patients who require retrieval for other reasons but who are co-incidentally infected with SARS-CoV-2 or shedding virus.The COVID-19 pandemic therefore poses a challenge to critical care retrieval systems, which often depend on small teams of specialists who live and work together closely. The infection or quarantining of a small absolute number of these staff could catastrophically compromise service delivery.Avoiding occupational exposure to COVID-19, and thereby ensuring service continuity, is the primary objective of aeromedical retrieval services during the pandemic. In this discussion paper we collaborated with helicopter emergency medical services(HEMS) worldwide to identify risks in retrieving COVID-19 patients, and develop strategies to mitigate these.Simulation involving the whole aeromedical retrieval team ensures that safety concerns can be addressed during the development of a standard operating procedure. Some services tested personal protective equipment and protocols in the aeromedical environment with simulation. We also incorporated experiences, standard operating procedures and approaches across several HEMS services internationally.As a result of this collaboration, we outline an approach to the safe aeromedical retrieval of a COVID-19 patient, and describe how this framework can be used to develop a local standard operating procedure.

MS4A4B is a GITR-associated membrane adapter, expressed by regulatory T cells, which modulates T cell activation.

In the aftermath of thymic negative selection, natural and adaptive regulatory T cells (Tregs) must acknowledge peripheral, "danger-free" self-Ag to ensure their sustained activity. In this paper, we show that natural and adaptive Tregs or T cells transduced with cDNA for Foxp3, just like Th1 cells, express members of the MS4A family of transmembrane molecules. Naive T cells transduced with MS4A4B become able to respond to lower levels of Ag. Using two family members, MS4A4B and MS4A6B, as baits in a yeast split-ubiquitin Treg library screen, we demonstrate their interaction with each other and with GITR, Orai1, and other surface receptors. Interaction of 4B with GITR augments GITR signaling and T cell IL-2 production in response to triggering with GITR ligand or anti-GITR Abs. This interaction provides a mechanism whereby MS4A family members, through lateral coassociation with costimulatory molecules, may amplify Ag signals. We propose that T cells preoccupied with immune defense use this MS4A family to enhance sensitivity to extrinsic Ag stimulation, ensuring its elimination, while Tregs use these adaptors to allow low level Ag signals to sustain regulatory function.