Incidence of admission ionised hypocalcaemia in paediatric major trauma: protocol for a systematic review and meta-analysis.

INTRODUCTION: Hypocalcaemia forms part of the 'diamond of death' in major trauma, alongside hypothermia, acidosis and coagulopathy. In adults, admission hypocalcaemia prior to transfusion is associated with increased mortality, increased blood transfusion requirements and coagulopathy. Data on paediatric major trauma patients are limited. This systematic review and meta-analysis aims to describe and synthesise the available evidence relevant to paediatric trauma, admission hypocalcaemia and outcome. METHODS AND ANALYSIS: The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines will be used to construct this review. A planned literature search for articles in the English language will be conducted from inception to the date of searches using MEDLINE on the EBSCO platform, CINAHL on the EBSCO platform and Embase on the Ovid platform. The grey literature will also be searched. Both title and abstract screening and full-text screening will be done by two reviewers, with an adjudicating third reviewer. Heterogeneity will be assessed using the I2 test, and the risk of bias will be assessed using the ROBINS-I tool. A meta-analysis will be undertaken using ratio measures (OR) and mean differences for measures of effect. When possible, the estimate of effect will be presented along with a CI and a p value. ETHICAL REVIEW AND DISSEMINATION: Ethical review is not required, as no original data will be collected. Results will be disseminated through peer-reviewed publications and at academic conferences. PROSPERO REGISTRATION NUMBER: CRD42023425172.

Comparison of deliberate self-harm incidents attended by Helicopter Emergency Medical Services before and during the first wave of COVID-19 in the East of England.

INTRODUCTION: There is significant interest in the mental health impact of the COVID-19 pandemic. Helicopter Emergency Medical Services (HEMS) attend the most seriously unwell and injured patients in the community; their data therefore present an early opportunity to examine self-harm trends. The primary aim was to compare the incidence of deliberate self-harm incident (DSH-I) encounters by HEMS before and during the first wave of COVID-19. METHODS: Data were obtained from all three East of England HEMS: total number of activations and stand-downs, number of DSH-I activations and stand-downs, self-harm mechanism and number of 'severe' DSH-I patient encounters, in two 61-day periods: 1 March to 30 April in 2019 (control) and 2020 (COVID-19). Severe DSH-I was defined as cardiac arrest and/or died prehospital. Proportions were compared with a Fisher's exact test. RESULTS: There were a total of 1725 HEMS activations: n=981 (control) and n=744 (COVID-19), a decrease of 24.2% during COVID-19. DSH-I patient encounters increased by 65.4%: n=26 (control) and n=43 (COVID-19). The proportion of encounters that were DSH-I and severe DSH-I both significantly increased during COVID-19: p=0.002 and p=0.001, respectively. The absolute number of hangings and falls from height both approximately tripled during COVID-19, whereas the number of other mechanisms remained almost constant. CONCLUSION: Despite a reduction in overall HEMS patient encounters, there were significant increases in both the proportion of DSH-Is and their severity attended by HEMS during the first wave of the COVID-19 pandemic in the East of England.

End-tidal and arterial carbon dioxide gradient in serious traumatic brain injury after prehospital emergency anaesthesia: a retrospective observational study.

OBJECTIVES: In the UK, 20% of patients with severe traumatic brain injury (TBI) receive prehospital emergency anaesthesia (PHEA). Current guidance recommends an end-tidal carbon dioxide (ETCO2) of 4.0-4.5 kPa (30.0-33.8 mm Hg) to achieve a low-normal arterial partial pressure of CO2 (PaCO2), and reduce secondary brain injury. This recommendation assumes a 0.5 kPa (3.8 mm Hg) ETCO2-PaCO2 gradient. However, the gradient in the acute phase of TBI is unknown. The primary aim was to report the ETCO2-PaCO2 gradient of TBI patients at hospital arrival. METHODS: A retrospective cohort study of adult patients with serious TBI, who received a PHEA by a prehospital critical care team in the East of England between 1 April 2015 and 31 December 2017. Linear regression was performed to test for correlation and reported as R-squared (R2). A Bland-Altman plot was used to test for paired ETCO2 and PaCO2 agreement and reported with 95% CI. ETCO2-PaCO2 gradient data were compared with a two-tailed, unpaired, t-test. RESULTS: 107 patients were eligible for inclusion. Sixty-seven patients did not receive a PaCO2 sample within 30 min of hospital arrival and were therefore excluded. Forty patients had complete data and were included in the final analysis; per protocol. The mean ETCO2-PaCO2 gradient was 1.7 (±1.0) kPa (12.8 mm Hg), with moderate correlation (R2=0.23, p=0.002). The Bland-Altman bias was 1.7 (95% CI 1.4 to 2.0) kPa with upper and lower limits of agreement of 3.6 (95% CI 3.0 to 4.1) kPa and -0.2 (95% CI -0.8 to 0.3) kPa, respectively. There was no evidence of a larger gradient in more severe TBI (p=0.29). There was no significant gradient correlation in patients with a coexisting serious thoracic injury (R2=0.13, p=0.10), and this cohort had a larger ETCO2-PaCO2 gradient, 2.0 (±1.1) kPa (15.1 mm Hg), p=0.01. Patients who underwent prehospital arterial blood sampling had an arrival PaCO2 of 4.7 (±0.2) kPa (35.1 mm Hg). CONCLUSION: There is only moderate correlation of ETCO2 and PaCO2 at hospital arrival in patients with serious TBI. The mean ETCO2-PaCO2 gradient was 1.7 (±1.0) kPa (12.8 mm Hg). Lower ETCO2 targets than previously recommended may be safe and appropriate, and there may be a role for prehospital PaCO2 measurement.