6 research outputs found
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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
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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 pre-hospital emergency anesthesia (PHEA). Current guidance recommends an end-tidal carbon dioxide (ETCO2) of 4.0-4.5kPa (30.0-33.8mmHg) to achieve a low-normal arterial partial pressure of CO2 (PaCO2), and reduce secondary brain injury. This recommendation assumes a 0.5kPa (3.8mmHg) 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. The secondary aims evaluated the relationship between the gradient and i) the severity of TBI, and ii) the presence of co-existing thoracic injury.
Methods
A consecutive series of adult patients with serious TBI that received a PHEA over a 32-month period were included (1 April 2015 to 31st December 2017). Patients without a PaCO2 sample within 30 minutes of hospital arrival were excluded. ETCO2 and PaCO2 data were compared with a Mann-Whitney U Test. Fisher’s exact test was used to compare proportions. Linear regression was performed to test for correlation and reported as R-squared (R2) with gradient of the slope (m).
Results
Forty patients had complete data. The median gradient was 1.6 [0.9-2.2] kPa (12.0mmHg), with moderate correlation (R2=0.23, p=0.002). There was no evidence of a larger gradient in more severe TBI (p=0.46). There was no significant gradient correlation in patients with a co-existing serious thoracic injury (R2=0.13, p=0.10), and this cohort had a larger gradient, 2.1 [1.2-5.6] kPa (15.8mmHg), p=0.01. Patients who underwent prehospital arterial blood sampling had an arrival PaCO2 of 4.6 [4.6-4.8] kPa (34.5mmHg).
Conclusion
There is only moderate correlation of ETCO2 and PaCO2 at hospital arrival in patients with serious TBI. The median ETCO2-PaCO2 gradient was 1.6 [0.9-2.2] kPa (12.0mmHg), greater than previously reported. Lower ETCO2 targets than previously recommended may be safe and appropriate, particularly in the presence of thoracic injury. There may be a role for pre-hospital PaCO2 measurement
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Incidence of admission ionised hypocalcaemia in paediatric major trauma: protocol for a systematic review and meta-analysis.
Peer reviewed: TrueAcknowledgements: The authors would like to acknowledge and thank Catherine Hancox and the Defence Medical Academic Library Team for their assistance with the search strategy.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
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Incidence of admission ionised hypocalcaemia in paediatric major trauma: protocol for a systematic review and meta-analysis
Peer reviewed: TrueAcknowledgements: The authors would like to acknowledge and thank Catherine Hancox and the Defence Medical Academic Library Team for their assistance with the search strategy.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