Detection of exhaled methane levels for monitoring trauma-related haemorrhage following blunt trauma: study protocol for a prospective observational study

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Abstract

Introduction

Early recognition and effective treatment of internal bleeding impose a cardinal challenge for trauma teams. The reduction of the superior mesenteric artery (SMA) blood flow is among the first compensatory responses to blood loss, thus being a promising candidate as a diagnostic tool for occult haemorrhage. Unfortunately, methods for monitoring the SMA flow have not been elaborated to date. Nevertheless, animal experiments suggest that exhaled methane (CH ₄) levels correspond to the SMA perfusion. We hypothesise that real-time detection of CH ₄ concentrations in the exhaled air is an applicable technique for the early recognition of haemorrhage in severely injured patients. We also hypothesise that exhaled CH ₄ levels reflect the volume of blood loss more accurately than conventional markers of blood loss and shock such as shock index, haemoglobin, base deficit, lactate, end-tidal carbon dioxide and sublingual microcirculatory indices.

Methods and analysis

One hundred and eleven severely injured (Injury Severity Score ≥16), intubated, bleeding patients sustaining blunt trauma will be included in this prospective observational study. Blood loss will be detected with CT and estimated with CT-linked radiologic software. Exhaled CH ₄ concentrations will be monitored by attaching a near-infrared laser technique-based photoacoustic spectroscopy apparatus to the exhalation outlet of the ventilator on patient arrival. The primary outcome is the volume of blood loss. Need for massive transfusion and 24-hour mortality will constitute secondary outcomes. The relation of exhaled CH ₄ to study outcomes and its performance in predicting blood loss in comparison with conventional shock markers and microcirculatory indices will be tested.

Ethics and dissemination

Our protocol (ID: 5400/2021-SZTE) has been registered on ClinicalTrials.gov (NCT04987411) and complies with the Declaration of Helsinki and has been approved by the medical ethics committee at the University of Szeged (Ref.nr.:121/2021-SZTE RKEB). It is in data collection phase, theresults will be shared with the scientific community through publication in a peer-reviewed journal.

Trial registration number

NCT04987411; ClinicalTrials.gov, registered on 27 July 2021.

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Most cited references 58

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Hemodynamic coherence and the rationale for monitoring the microcirculation

Can Ince (2015)

This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation following conditions of shock and cardiovascular compromise, and why it is important to monitor the microcirculation in such conditions. The article emphasizes that if resuscitation procedures are based on the correction of systemic variables, there must be coherence between the macrocirculation and microcirculation if systemic hemodynamic-driven resuscitation procedures are to be effective in correcting organ perfusion and oxygenation. However, in conditions of inflammation and infection, which often accompany states of shock, vascular regulation and compensatory mechanisms needed to sustain hemodynamic coherence are lost, and the regional circulation and microcirculation remain in shock. We identify four types of microcirculatory alterations underlying the loss of hemodynamic coherence: type 1, heterogeneous microcirculatory flow; type 2, reduced capillary density induced by hemodilution and anemia; type 3, microcirculatory flow reduction caused by vasoconstriction or tamponade; and type 4, tissue edema. These microcirculatory alterations can be observed at the bedside using direct visualization of the sublingual microcirculation with hand-held vital microscopes. Each of these alterations results in oxygen delivery limitation to the tissue cells despite the presence of normalized systemic hemodynamic variables. Based on these concepts, we propose how to optimize the volume of fluid to maximize the oxygen-carrying capacity of the microcirculation to transport oxygen to the tissues.

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Early prediction of massive transfusion in trauma: simple as ABC (assessment of blood consumption)?

A Dossett, William Dutton, Andrea C Nunez … (2009)

Massive transfusion (MT) occurs in about 3% of civilian and 8% of military trauma patients. Although many centers have implemented MT protocols, most do not have a standardized initiation policy. The purpose of this study was to validate previously described MT scoring systems and compare these to a simplified nonlaboratory dependent scoring system (Assessment of Blood Consumption [ABC] score). Retrospective cohort of all level I adult trauma patients transported directly from the scene (July 2005 to June 2006). Trauma-Associated Severe Hemorrhage (TASH) and McLaughlin scores calculated according to published methods. ABC score was assigned based on four nonweighted parameters: penetrating mechanism, positive focused assessment sonography for trauma, arrival systolic blood pressure of 90 mm Hg or less, and arrival heart rate > or = 120 bpm. Area under the receiver operating characteristic curve (AUROC) used to compare scoring systems. Five hundred ninety-six patients were available for analysis; and the overall MT rate of 12.4%. Patients receiving MT had higher TASH (median, 6 vs. 13; p < 0.001), McLaughlin (median, 2.4 vs. 3.4; p < 0.001) and ABC (median, 1 vs. 2; p < 0.001) scores. TASH (AUROC = 0.842), McLaughlin (AUROC = 0.846), and ABC (AUROC = 0.842) scores were all good predictors of MT, and the difference between the scores was not statistically significant. ABC score of 2 or greater was 75% sensitive and 86% specific for predicting MT (correctly classified 85%). The ABC score, which uses nonlaboratory, nonweighted parameters, is a simple and accurate in identifying patients who will require MT as compared with those previously published scores.

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The Shock Index revisited – a fast guide to transfusion requirement? A retrospective analysis on 21,853 patients derived from the TraumaRegister DGU®

Manuel Mutschler, Ulrike Nienaber, Matthias Münzberg … (2013)

Introduction Isolated vital signs (for example, heart rate or systolic blood pressure) have been shown unreliable in the assessment of hypovolemic shock. In contrast, the Shock Index (SI), defined by the ratio of heart rate to systolic blood pressure, has been advocated to better risk-stratify patients for increased transfusion requirements and early mortality. Recently, our group has developed a novel and clinical reliable classification of hypovolemic shock based upon four classes of worsening base deficit (BD). The objective of this study was to correlate this classification to corresponding strata of SI for the rapid assessment of trauma patients in the absence of laboratory parameters. Methods Between 2002 and 2011, data for 21,853 adult trauma patients were retrieved from the TraumaRegister DGU® database and divided into four strata of worsening SI at emergency department arrival (group I, SI <0.6; group II, SI ≥0.6 to <1.0; group III, SI ≥1.0 to <1.4; and group IV, SI ≥1.4) and were assessed for demographics, injury characteristics, transfusion requirements, fluid resuscitation and outcomes. The four strata of worsening SI were compared with our recently suggested BD-based classification of hypovolemic shock. Results Worsening of SI was associated with increasing injury severity scores from 19.3 (± 12) in group I to 37.3 (± 16.8) in group IV, while mortality increased from 10.9% to 39.8%. Increments in SI paralleled increasing fluid resuscitation, vasopressor use and decreasing hemoglobin, platelet counts and Quick’s values. The number of blood units transfused increased from 1.0 (± 4.8) in group I to 21.4 (± 26.2) in group IV patients. Of patients, 31% in group III and 57% in group IV required ≥10 blood units until ICU admission. The four strata of SI discriminated transfusion requirements and massive transfusion rates equally with our recently introduced BD-based classification of hypovolemic shock. Conclusion SI upon emergency department arrival may be considered a clinical indicator of hypovolemic shock in respect to transfusion requirements, hemostatic resuscitation and mortality. The four SI groups have been shown to equal our recently suggested BD-based classification. In daily clinical practice, SI may be used to assess the presence of hypovolemic shock if point-of-care testing technology is not available.

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Author and article information

Journal

Journal ID (nlm-ta): BMJ Open

Journal ID (iso-abbrev): BMJ Open

Journal ID (hwp): bmjopen

Journal ID (publisher-id): bmjopen

Title: BMJ Open

Publisher: BMJ Publishing Group (BMA House, Tavistock Square, London, WC1H 9JR )

ISSN (Electronic): 2044-6055

Publication date Collection: 2022

Publication date (Electronic): 6 July 2022

Volume: 12

Issue: 7

Electronic Location Identifier: e057872

Affiliations

[1 ]departmentDepartment of Traumatology , University of Szeged , Szeged, Hungary

[2 ]departmentDepartment of Medical Physics and Informatics , University of Szeged , Szeged, Hungary

[3 ]departmentInstitute of Surgical Research , University of Szeged , Szeged, Hungary

[4 ]departmentDepartment of Sports Medicine , University of Szeged , Szeged, Hungary

Author notes

[Correspondence to ] Dr Petra Hartmann; hartmann.petra@ 123456med.u-szeged.hu

Author information

Péter Jávor http://orcid.org/0000-0002-5628-9355

Article

Publisher ID: bmjopen-2021-057872

DOI: 10.1136/bmjopen-2021-057872

PMC ID: 9260765

PubMed ID: 35793921

SO-VID: 66f124be-3ecc-499a-a2b2-5945e9269ea3

License:

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

History

Date received : 30 September 2021

Date accepted : 17 June 2022

Funding

Funded by: National Research Development and Innovation Office OTKA Research;

Award ID: FK138839

Funded by: Hungarian Academy of Sciences Bolyai János Research grant;

Award ID: BO/00605/21/5

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ScienceOpen disciplines: Medicine

Keywords: accident & emergency medicine,bleeding disorders & coagulopathies,protocols & guidelines,trauma management

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ScienceOpen disciplines: Medicine

Keywords: accident & emergency medicine, bleeding disorders & coagulopathies, protocols & guidelines, trauma management

Detection of exhaled methane levels for monitoring trauma-related haemorrhage following blunt trauma: study protocol for a prospective observational study

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IEEE: COVID-19 related research

Most cited references 58

Hemodynamic coherence and the rationale for monitoring the microcirculation

Early prediction of massive transfusion in trauma: simple as ABC (assessment of blood consumption)?

The Shock Index revisited – a fast guide to transfusion requirement? A retrospective analysis on 21,853 patients derived from the TraumaRegister DGU®

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