Systematic review of oxygenation and clinical outcomes to inform oxygen targets in critically ill trauma patients

Oxidative stress in trauma patients receiving a restrictive or liberal oxygen strategy - A sub-study of the TRAUMOX2 trial

INTRODUCTION

A liberal supplemental oxygen approach is recommended for all severely injured trauma patients despite limited evidence. Liberal oxygen administration may cause oxidative stress. The aim of this study was to investigate the effect of an early restrictive oxygen strategy versus a liberal oxygen strategy in adult trauma patients on biomarkers of oxidative stress within 48 h of hospital admission.

MATERIALS AND METHODS

This was a single-centre, sub-study of an international, randomised controlled trial TRAUMOX2. In TRAUMOX2, patients were randomised shortly after trauma to a restrictive oxygen strategy (arterial oxygen saturation target of 94 %) or a liberal oxygen strategy (12-15 L of oxygen per minute or fraction of inspired oxygen of 0.6-1.0) for 8 h. Blood samplings were performed at four time points within 48 h after randomisation: upon arrival at the trauma centre, and at eight, 24, and 48 h post-randomisation. The primary outcome was the plasma level of malondialdehyde (MDA) 24 h post-randomisation. Secondary outcomes were numerous, and included the level of MDA at other time points, superoxide dismutase (SOD) at all time points, 30-day mortality, and major respiratory complications.

RESULTS

The sub-study included 90 adult trauma patients. The median MDA levels at 24 h post-randomisation was 60.9 μM (95 % CI 49.5 to 73.4) in the restrictive oxygen group and 56.7 μM (95 % CI 46.9 to 68.2) in the liberal oxygen group, corresponding to a difference of -4.2 μM (95 % CI -19.8 to 10.5; P = 0.35). No significant differences were found in MDA or SOD at the other time points either. Neither did we find a significant difference in 30-day mortality or major respiratory complications.

CONCLUSIONS

In this sub-study of the TRAUMOX2 trial, no significant differences were found in biomarkers of oxidative stress between a restrictive oxygen strategy and liberal oxygen strategy in adult trauma patients.

Early Restrictive vs Liberal Oxygen for Trauma Patients: The TRAUMOX2 Randomized Clinical Trial

Importance

Early administration of supplemental oxygen for all severely injured trauma patients is recommended, but liberal oxygen treatment has been associated with increased risk of death and respiratory complications.

Objective

To determine whether an early 8-hour restrictive oxygen strategy compared with a liberal oxygen strategy in adult trauma patients would reduce death and/or major respiratory complications.

Design, Setting, and Participants

This randomized controlled trial enrolled adult trauma patients transferred directly to hospitals, triggering a full trauma team activation with an anticipated hospital stay of a minimum of 24 hours from December 7, 2021, to September 12, 2023. This multicenter trial was conducted at 15 prehospital bases and 5 major trauma centers in Denmark, the Netherlands, and Switzerland. The 30-day follow-up period ended on October 12, 2023. The primary outcome was assessed by medical specialists in anesthesia and intensive care medicine blinded to the randomization.

Interventions

In the prehospital setting or on trauma center admission, patients were randomly assigned 1:1 to a restrictive oxygen strategy (arterial oxygen saturation target of 94%) (n = 733) or liberal oxygen strategy (12-15 L of oxygen per minute or fraction of inspired oxygen of 0.6-1.0) (n = 724) for 8 hours.

Main Outcomes and Measures

The primary outcome was a composite of death and/or major respiratory complications within 30 days. The 2 key secondary outcomes, death and major respiratory complications within 30 days, were assessed individually.

Results

Among 1979 randomized patients, 1508 completed the trial (median [IQR] age, 50 [31-65] years; 73% male; and median Injury Severity Score was 14 [9-22]). Death and/or major respiratory complications within 30 days occurred in 118 of 733 patients (16.1%) in the restrictive oxygen group and 121 of 724 patients (16.7%) in the liberal oxygen group (odds ratio, 1.01 [95% CI, 0.75 to 1.37]; P = .94; absolute difference, 0.56 percentage points [95% CI, -2.70 to 3.82]). No significant differences were found between groups for each component of the composite outcome. Adverse and serious adverse events were similar across groups, with the exception of atelectasis, which was less common in the restrictive oxygen group compared with the liberal oxygen group (27.6% vs 34.7%, respectively).

Conclusions and Relevance

In adult trauma patients, an early restrictive oxygen strategy compared with a liberal oxygen strategy initiated in the prehospital setting or on trauma center admission for 8 hours did not significantly reduce death and/or major respiratory complications within 30 days.

Trial Registration

ClinicalTrials.gov Identifier: NCT05146700.

Clinicians' attitudes towards supplemental oxygen for trauma patients - A survey

INTRODUCTION

The Advanced Trauma Life Support guidelines (ATLS; 2018, 10th ed.) recommend an early and liberal supplemental oxygen for all severely injured trauma patients to prevent hypoxaemia. As of 2024, these guidelines remain the most current. This may lead to hyperoxaemia, which has been associated with increased mortality and respiratory complications. We aimed to investigate the attitudes among clinicians, defined as physicians and prehospital personnel, towards the use of supplemental oxygen in trauma cases.

MATERIALS AND METHODS

A European, web-based, cross-sectional survey was conducted consisting of 23 questions. The primary outcome was the question: "In your opinion, should all severely injured trauma patients always be given supplemental oxygen, regardless of arterial oxygen saturation measured by pulse oximetry?".

RESULTS

The survey was answered by 707 respondents, which corresponded to a response rate of 52 %. The respondents were predominantly male (76 %), with the largest representation from Denmark (82 %), and primarily educated as physicians (62 %). A majority of respondents (73 % [95 % CI: 70 to 76 %]) did not support that supplemental oxygen should always be provided to all severely injured trauma patients without consideration of their arterial oxygen saturation as measured by pulse oximetry (SpO2), with no significant difference between physicians and non-physicians (p = 0.08). Based on the respondents' preferred dosages, the median initial administered dosage of supplemental oxygen for spontaneously breathing trauma patients with a normal SpO2 in the first few hours after trauma was 0 (interquartile range [IQR] 0-3) litres per minute, with 58 % of respondents opting not to provide any supplemental oxygen. The lowest acceptable SpO2 goal in the first few hours after trauma was 94 % (IQR 92-95). In clinical scenarios with TBI, higher dosage of supplemental oxygen and fraction of inspired oxygen (FiO2) were preferred, as well as targeting partial pressure of oxygen in arterial blood as opposed to adjusting the FiO2 directly, compared to no TBI.

CONCLUSION

Almost three out of four clinicians did not support the administration of supplemental oxygen to all severely injured trauma patients, regardless of SpO2. This corresponds to a more restrictive approach than recommended in the current ATLS (2018, 10th ed.) guidelines.

High risk and low prevalence diseases: Blast injuries

INTRODUCTION

Blast injury is a unique condition that carries a high rate of morbidity and mortality, often with mixed penetrating and blunt injuries.

OBJECTIVE

This review highlights the pearls and pitfalls of blast injuries, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Explosions may impact multiple organ systems through several mechanisms. Patients with suspected blast injury and multisystem trauma require a systematic evaluation and resuscitation, as well as investigation for injuries specific to blast injuries. Blast injuries most commonly affect air-filled organs but can also result in severe cardiac and brain injury. Understanding blast injury patterns and presentations is essential to avoid misdiagnosis and balance treatment of competing interests of patients with polytrauma. Management of blast victims can also be further complicated by burns, crush injury, resource limitation, and wound infection. Given the significant morbidity and mortality associated with blast injury, identification of various injury patterns and appropriate management are essential.

CONCLUSIONS

An understanding of blast injuries can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

Hyperoxia is associated with a greater risk for mortality in critically ill traumatic brain injury patients than in critically ill trauma patients without brain injury

OBJECTIVE

The role of hyperoxia in patients with traumatic brain injury (TBI) remains controversial. The objective of this study was to determine the association between hyperoxia and mortality in critically ill TBI patients compared to critically ill trauma patients without TBI.

DESIGN

Secondary analysis of a multicenter retrospective cohort study.

SETTING

Three regional trauma centers in Colorado, USA, between October 1, 2015, and June 30, 2018.

PATIENTS

We included 3464 critically injured adults who were admitted to an intensive care unit (ICU) within 24 h of arrival and qualified for inclusion into the state trauma registry. We analyzed all available SpO2 values during the first seven ICU days. The primary outcome was in-hospital mortality. Secondary outcomes included the proportion of time spent in hyperoxia (defined as SpO2 > 96%) and ventilator-free days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In-hospital mortality occurred in 163 patients (10.7%) in the TBI group and 101 patients (5.2%) in the non-TBI group. After adjusting for ICU length of stay, TBI patients spent a significantly greater amount of time in hyperoxia versus non-TBI patients (p = 0.024). TBI status significantly modified the effect of hyperoxia on mortality. At each specific SpO2 level, the risk of mortality increases with increasing FiO2 for both patients with and without TBI. This trend was more pronounced at lower FiO2 and higher SpO2 values, where a greater number of patient observations were obtained. Among patients who required invasive mechanical ventilation, TBI patients required significantly more days of ventilation to day 28 than non-TBI patients.

CONCLUSIONS

Critically ill trauma patients with a TBI spend a greater proportion of time in hyperoxia compared to those without a TBI. TBI status significantly modified the effect of hyperoxia on mortality. Prospective clinical trials are needed to better assess a possible causal relationship.

A multicenter cluster randomized, stepped wedge implementation trial for targeted normoxia in critically ill trauma patients: study protocol and statistical analysis plan for the Strategy to Avoid Excessive Oxygen (SAVE-O2) trial

Background

Targeted normoxia (SpO₂ 90–96% or PaO₂ 60–100 mmHg) may help to conserve oxygen and improve outcomes in critically ill patients by avoiding potentially harmful hyperoxia. However, the role of normoxia for critically ill trauma patients remains uncertain. The objective of this study is to describe the study protocol and statistical analysis plan for the Strategy to Avoid Excessive Oxygen for Critically Ill Trauma Patients (SAVE-O2) clinical trial.

Methods

Design, setting, and participants: Protocol for a multicenter cluster randomized, stepped wedge implementation trial evaluating the effectiveness of a multimodal intervention to target normoxia in critically ill trauma patients at eight level 1 trauma centers in the USA. Each hospital will contribute pre-implementation (control) and post-implementation (intervention) data. All sites will begin in the control phase with usual care. When sites reach their randomly assigned time to transition, there will be a one-month training period, which does not contribute to data collection. Following the 1-month training period, the site will remain in the intervention phase for the duration of the trial.

Main outcome measures: The primary outcome will be supplemental oxygen-free days, defined as the number of days alive and not on supplemental oxygen. Secondary outcomes include in-hospital mortality to day 90, hospital-free days to day 90, ventilator-free days (VFD) to day 28, time to room air, Glasgow Outcome Score (GOS), and duration of time receiving supplemental oxygen.

Discussion

SAVE-O2 will determine if a multimodal intervention to improve compliance with targeted normoxia will safely reduce the need for concentrated oxygen for critically injured trauma patients. These data will inform military stakeholders regarding oxygen requirements for critically injured warfighters, while reducing logistical burden in prolonged combat casualty care.

Trial registration

ClinicalTrials.govNCT04534959. Registered September 1, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05688-6.

Association Between Hyperoxia, Supplemental Oxygen, and Mortality in Critically Injured Patients

Supplemental Digital Content is available in the text.

OBJECTIVES:

Hyperoxia is common among critically ill patients and may increase morbidity and mortality. However, limited evidence exists for critically injured patients. The objective of this study was to determine the association between hyperoxia and in-hospital mortality in adult trauma patients requiring ICU admission.

DESIGN, SETTING, AND PARTICIPANTS:

This multicenter, retrospective cohort study was conducted at two level I trauma centers and one level II trauma center in CO between October 2015 and June 2018. All adult trauma patients requiring ICU admission within 24 hours of emergency department arrival were eligible. The primary exposure was oxygenation during the first 7 days of hospitalization.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

Primary outcome was in-hospital mortality. Secondary outcomes were hospital-free days and ventilator-free days. We included 3,464 critically injured patients with a mean age of 52.6 years. Sixty-five percent were male, and 66% had blunt trauma mechanism of injury. The primary outcome of in-hospital mortality occurred in 264 patients (7.6%). Of 226,057 patient-hours, 46% were spent in hyperoxia (oxygen saturation > 96%) and 52% in normoxia (oxygen saturation 90–96%). During periods of hyperoxia, the adjusted risk for mortality was higher with greater oxygen administration. At oxygen saturation of 100%, the adjusted risk scores for mortality (95% CI) at Fio₂ of 100%, 80%, 60%, and 50% were 6.4 (3.5–11.8), 5.4 (3.4–8.6), 2.7 (1.7–4.1), and 1.5 (1.1–2.2), respectively. At oxygen saturation of 98%, the adjusted risk scores for mortality (95% CI) at Fio₂ of 100%, 80%, 60%, and 50% were 7.7 (4.3–13.5), 6.3 (4.1–9.7), 3.2 (2.2–4.8), and 1.9 (1.4–2.7), respectively.

CONCLUSIONS:

During hyperoxia, higher oxygen administration was independently associated with a greater risk of mortality among critically injured patients. Level of evidence: Cohort study, level III.