Lower vs Higher Oxygenation Target and Days Alive Without Life Support in COVID-19: The HOT-COVID Randomized Clinical Trial

Oxygen therapy in the intensive care unit

Oxygen therapy is a crucial treatment method for maintaining vital signs in patients in the intensive care unit. However, several controversial issues have emerged regarding its clinical application. This article analyzes current research trends in oxygen therapy in the intensive care unit and provides guidance and recommendations. Relevant literature was retrieved from the Web of Science Core Collection, and keyword co-occurrence and highly cited literature hotspot analyses were conducted using VOSviewer 1.6.19 software. The key topics related to oxygen therapy in the intensive care unit primarily focus on four areas: oxygen therapy and mechanical ventilation in the intensive care unit, extracorporeal membrane oxygenation therapy for coronavirus disease 2019 and its role in reducing mortality, research on hypoxia and oxygen saturation monitoring, and oxygen inhalation therapy in the intensive care unit. The analysis of highly cited literature indicates that the main research hotspots regarding oxygen therapy used in the intensive care unit focus primarily on conservative oxygen therapy, high-flow nasal oxygen therapy, comparisons of high- and low-oxygenation strategies, and research on hyperbaric oxygen therapy. First, the potential of conservative oxygen therapy to reduce mortality rates in the intensive care unit has attracted considerable attention; however, further clinical studies are needed to validate its optimal parameters and suitable patient populations. Second, high-flow nasal oxygen therapy has been shown to be effective in alleviating respiratory distress and reducing the need for intubation. This therapy can deliver oxygen flows of up to 60 L/min, effectively improving respiratory distress and decreasing intubation demands. In patients subjected to high-risk extubation, the combination of high-flow nasal oxygen therapy and noninvasive ventilation significantly lowers the rate of reintubation, making the combined approach one of the best strategies to prevent respiratory failure after extubation in the intensive care unit. Third, there are differences between lower and higher oxygenation strategies regarding their effects on patient mortality, long-term outcomes, and clinician preferences; however, there is currently no clear evidence indicating which strategy is superior. Clinicians' preferences regarding various oxygenation targets may impact the design of future studies. Finally, hyperbaric oxygen therapy is recognized as an effective supportive treatment for various critical conditions and has significant application value in acute severe traumatic brain injury, cerebral resuscitation, and cardiopulmonary resuscitation. Currently, researchers are continually exploring the latest oxygen therapies in the intensive care unit. Several randomized controlled clinical trials investigating automated oxygen control, novel high-flow nasal oxygen therapy, and combined oxygen therapy are underway. The results of these trials should be closely observed. Overall, this article provides a systematic review and valuable reference for the scientific and rational application of oxygen therapy in the intensive care unit. Future research should focus on verifying the optimal parameters of conservative oxygen therapy, assessing oxygen needs in different patient populations, evaluating the long-term effects of oxygen treatment, and developing novel oxygen therapy technologies and devices.

Oxygen targets in critically ill patients: from pathophysiology to population enrichment strategies

Oxygen supplementation is widely used to enhance oxygen delivery and to treat or prevent hypoxia; however, it requires careful management to avoid the harmful effects of excessive oxygen exposure. Both hyperoxia (inspiratory oxygen fraction exceeding 0.21) and hyperoxemia (arterial oxygen tension oxygen partial pressure [PaO2] > 100 mmHg) can contribute to lung injury, promote systemic vasoconstriction, and increase the production of reactive oxygen species, which can impair macromolecular and cellular functions. Conversely, in certain situations, hyperoxemia may provide benefits, such as hemodynamic stabilization in hyperdynamic shock, immunomodulation, and bactericidal effects. The literature presents conflicting evidence regarding the impact of different oxygen targets (i.e., PaO2 and/or peripheral saturation of oxygen [SpO2]) on both short- and long-term outcomes in patients with acute critical conditions, such as acute respiratory distress syndrome, sepsis, cardiac arrest, and acute central nervous system injuries. These discrepancies may stem from the small differences between the oxygenation targets used in randomized trials, the physiological limitations of PaO2 and SpO2 targets, which reflect blood oxygen content rather than oxygen delivery, the lack of measurements of microvascular function or oxygen delivery, and the heterogeneity in treatment response. Furthermore, advanced analytical methods (e.g., machine learning) are emerging as promising tools to implement population enrichment strategies. By refining patient sub-group identification, these approaches can significantly optimize precision medicine, enabling more personalized oxygen therapy tailored to individual patient characteristics.

Modelling the distribution of the oxygen-haemoglobin dissociation curve in vivo: An observational study

Few studies have explored the variability of the oxygen-haemoglobin dissociation curve in vivo. 96,428 blood gas measurements were obtained (80,376 arterial, 6959 venous) from a cohort of 7656 patients who were admitted to a large UK teaching hospital between 1 February 2020 and 31 December 2021 for a Covid-19 related admission with a positive PCR. There was consistent variation of the distribution of the oxygen-haemoglobin curve across most oxygen saturation strata with typical values at 91-92 % saturation (mean 8.1kPa, standard deviation sd 0.6 kPa or 60.8 mmHg sd 4.5 mmHg), with the exception of the highest strata of oxygen saturation of 99-100 % (mean 17.7 kPa, sd 8.1kPa or 132 mmHg sd 60.8). The higher oxygen partial pressures at higher oxygen saturations are a concern in view of the increased mortality observed in RCTs of higher oxygen saturation targets. However, the observational study design precludes any attribution of causality.

Managing Refractory Hypoxemia in Acute Respiratory Distress Syndrome Obese Patients with Veno-Venous Extra-Corporeal Membrane Oxygenation: A Narrative Review

Veno-venous extracorporeal membrane oxygenation (vvECMO) is a life-saving intervention for severe respiratory failure unresponsive to conventional therapies. However, managing refractory hypoxemia in morbidly obese patients poses significant challenges due to the unique physiological characteristics of this population, including hyperdynamic circulation, elevated cardiac output, and increased oxygen consumption. These factors can limit the effectiveness of vvECMO by diluting arterial oxygen content and complicating oxygen delivery. Refractory hypoxemia in obese patients supported by vvECMO often stems from an imbalance between ECMO blood flow and cardiac output. Hyperdynamic circulation exacerbates the recirculation of oxygenated blood and impairs the efficiency of oxygen transfer. To address these challenges, a stepwise, individualized approach is essential. Strategies to reduce oxygen consumption include deep sedation, neuromuscular blockade, and temperature control. Cardiac output modulation can be achieved through beta-blockers and cautious therapeutic hypothermia. Optimizing oxygen delivery involves improving residual lung function; high positive end-expiratory pressure ventilation guided by esophageal pressure monitoring; prone positioning; and adjustments to the ECMO circuit, such as using dual oxygenators, larger membranes, or additional drainage cannulas. This review highlights the interplay of physiological adaptations and technical innovations required to overcome the challenges of managing refractory hypoxemia in obese patients during vvECMO. By addressing the complexities of high cardiac output and obesity, clinicians can enhance the effectiveness of vvECMO and improve outcomes for this high-risk population.

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.

Effects of very early hyperoxemia on neurologic outcome after out-of-hospital cardiac arrest: A secondary analysis of the TTM-2 trial

PURPOSE

Hyperoxemia is common in patients resuscitated after out-of-hospital cardiac arrest (OHCA) admitted to the intensive care unit (ICU) and may increase the risk of mortality. However, the effect of hyperoxemia on functional outcome, specifically related to the timing of exposure to hyperoxemia, remains unclear.

METHODS

The secondary analysis of the Target Temperature Management 2 (TTM-2) randomized trial. The primary aim was to identify the best cut-off of partial arterial pressure of oxygen (PaO2) to predict poor functional outcome within the first 24 h from admission, with this period further separated into 'very early' (0-4 h), 'early' (8-24 h), and 'late' (28-72 h) periods. Hyperoxemia was defined as the highest PaO2 recorded during each period. Poor functional outcome was defined as a 6 months modified Rankin Score (mRS) of 4 to 6.

RESULTS

A total of 1,631 patients were analysed for the 'very early' and 'early' periods, and 1,591 in the 'late period'. In a multivariate logistic regression model, a PaO2 above 245 mmHg during the very early phase was independently associated with a higher probability of poor functional outcome (Odds Ratio, OR = 1.63, 95 % Confidence Interval, CI 1.08-2.44, p = 0.019). No significant associations were found for the later periods.

CONCLUSIONS

Very early hyperoxemia after ICU admission is associated with higher risk of poor functional outcome after OHCA. Avoiding hyperoxia in the initial hours after resuscitation should be considered.

Heterogeneity of treatment effect: the case for individualising oxygen therapy in critically ill patients

Oxygen therapy is ubiquitous in critical illness but oxygenation targets to guide therapy remain controversial despite several large randomised controlled trials (RCTs). Findings from RCTs evaluating different approaches to oxygen therapy in critical illness present a confused picture for several reasons. Differences in both oxygen target measures (e.g. oxygen saturation or partial pressure) and the numerical thresholds used to define lower and higher targets complicate comparisons between trials. The duration of and adherence to oxygenation targets is also variable with consequent substantial variation in both the dose and the dose separation. Finally, heterogeneity of treatment effects (HTE) may also be a significant factor. HTE is defined as non-random variation in the benefit or harm of a treatment, in which the variation is associated with or attributable to patient characteristics. This narrative review aims to make the case that such heterogeneity is likely in relation to oxygen therapy for critically ill patients and that this has significant implications for the design and interpretation of trials of oxygen therapy in this context. HTE for oxygen therapy amongst critically ill patients may explain the contrasting results from different clinical trials of oxygen therapy. Individualised oxygen therapy may overcome this challenge, and future studies should incorporate ways to evaluate this approach.

Sociodemographic, Clinical, and Ventilatory Factors Influencing COVID-19 Mortality in the ICU of a Hospital in Colombia

BACKGROUND AND OBJECTIVES

The COVID-19 pandemic posed significant challenges to healthcare systems worldwide, and mortality rates were driven by a complex interaction of patient-specific factors, one of the most important being those related to the scheduling of invasive mechanical ventilation. This study examined the sociodemographic, clinical, and ventilatory factors associated with mortality in COVID-19 patients admitted to the ICU of a hospital in Colombia.

METHODS

A retrospective cohort study was conducted, involving 116 patients over the age of 18 who were admitted to the ICU with a confirmed diagnosis of COVID-19 between March 2020 and May 2021. Data were collected from the patients' medical records. Statistical analysis was performed using SPSS version 24®. Odds ratios (OR) and 95% confidence intervals were calculated to identify factors associated with COVID-19 mortality, followed by adjustment through binary logistic regression.

RESULTS

It was found that 65.5% of the patients were male, with a mean age of 64 ± 14 years, and the overall mortality rate was 49%. Factors significantly associated with higher mortality included male sex (OR: 6.9, 95% CI: 1.5-31.7), low oxygen saturation on admission (OR: 7.6, 95% CI: 1.1-55), and PEEP settings at 96 h (OR: 8, 95% CI: 1.4-45). Mortality was not influenced by socioeconomic status or health system affiliation.

CONCLUSIONS

This study identified male sex, age over 65 years, PEEP greater than 10 cmH2O at 96 h of mechanical ventilation, and low oxygen saturation as significant factors associated with higher mortality in COVID-19 patients, while no significant associations were found with socioeconomic status or health system affiliation. These findings highlight the importance of focusing on clinical management and ventilatory strategies in reducing mortality, particularly for high-risk groups, rather than relying on socioeconomic factors as predictors of outcomes.

Subgroup analyses and heterogeneity of treatment effects in randomized trials: a primer for the clinician

PURPOSE OF REVIEW

To date, most randomized clinical trials in critical care report neutral overall results. However, research as to whether heterogenous responses underlie these results and give opportunity for personalized care is gaining momentum but has yet to inform clinical practice guidance. Thus, we aim to provide an overview of methodological approaches to estimating heterogeneity of treatment effects in randomized trials and conjecture about future paths to application in patient care.

RECENT FINDINGS

Despite their limitations, traditional subgroup analyses are still the most reported approach. More recent methods based on subphenotyping, risk modeling and effect modeling are still uncommonly embedded in primary reports of clinical trials but have provided useful insights in secondary analyses. However, further simulation studies and subsequent guidelines are needed to ascertain the most efficient and robust manner to validate these results for eventual use in practice.

SUMMARY

There is an increasing interest in approaches that can identify heterogeneity in treatment effects from randomized clinical trials, extending beyond traditional subgroup analyses. While prospective validation in further studies is still needed, these approaches are promising tools for design, interpretation, and implementation of clinical trial results.

Long-term mortality and health-related quality of life with lower versus higher oxygenation targets in intensive care unit patients with COVID-19 and severe hypoxaemia

PURPOSE

The aim of this study was to evaluate one-year outcomes of lower versus higher oxygenation targets in intensive care unit (ICU) patients with coronavirus disease 2019 (COVID-19) and severe hypoxaemia.

METHODS

We conducted pre-planned analyses of one-year mortality and health-related quality of life (HRQoL) in the Handling Oxygenation Targets in COVID-19 trial. The trial randomised 726 ICU patients with COVID-19 and hypoxaemia to partial pressure of arterial oxygen targets of 8 kPa (60 mmHg) versus 12 kPa (90 mmHg) during ICU stay up to 90 days, including readmissions. HRQoL was assessed using EuroQol visual analogue scale (EQ-VAS) and 5-level 5-dimension questionnaire (EQ-5D-5L). Outcomes were analysed in the intention-to-treat population. Non-survivors were assigned the worst possible score (zero), and multiple imputation was applied for missing EQ-VAS values.

RESULTS

We obtained one-year vital status for 691/726 (95.2%) of patients and HRQoL data for 642/726 (88.4%). At one year, 117/348 (33.6%) of patients in the lower-oxygenation group had died compared to 134/343 (39.1%) in the higher-oxygenation group (adjusted risk ratio: 0.85; 98.6% confidence interval (CI) 0.66-1.09; p = 0.11). Median EQ-VAS was 50 (interquartile range, 0-80) versus 40 (0-75) (adjusted mean difference: 4.8; 98.6% CI  - 2.2 to 11.9; p = 0.09) and EQ-5D-5L index values were 0.61 (0-0.81) in the lower-oxygenation group versus 0.43 (0-0.79) (p = 0.20) in the higher-oxygenation group, respectively.

CONCLUSION

Among adult ICU patients with COVID-19 and severe hypoxaemia, one-year mortality results were most compatible with benefit of the lower oxygenation target, which did not appear to result in more survivors with poor quality of life.

The physiological basis for individualized oxygenation targets in critically ill patients with circulatory shock

BACKGROUND

Circulatory shock, defined as decreased tissue perfusion, leading to inadequate oxygen delivery to meet cellular metabolic demands, remains a common condition with high morbidity and mortality. Rapid restitution and restoration of adequate tissue perfusion are the main treatment goals. To achieve this, current hemodynamic strategies focus on adjusting global physiological variables such as cardiac output (CO), hemoglobin (Hb) concentration, and arterial hemoglobin oxygen saturation (SaO2). However, it remains a challenge to identify optimal targets for these global variables that best support microcirculatory function. Weighting up the risks and benefits is especially difficult for choosing the amount of oxygen supplementation in critically ill patients. This review assesses the physiological basis for oxygen delivery to the tissue and provides an overview of the relevant literature to emphasize the importance of considering risks and benefits and support decision making at the bedside.

PHYSIOLOGICAL PREMISES

Oxygen must reach the tissue to enable oxidative phosphorylation. The human body timely detects hypoxia via different mechanisms aiming to maintain adequate tissue oxygenation. In contrast to the pulmonary circulation, where the main response to hypoxia is arteriolar vasoconstriction, the regulatory mechanisms of the systemic circulation aim to optimize oxygen availability in the tissues. This is achieved by increasing the capillary density in the microcirculation and the capillary hematocrit thereby increasing the capacity of oxygen diffusion from the red blood cells to the tissue. Hyperoxia, on the other hand, is associated with oxygen radical production, promoting cell death.

CURRENT STATE OF RESEARCH

Clinical trials in critically ill patients have primarily focused on comparing macrocirculatory endpoints and outcomes based on stroke volume and oxygenation targets. Some earlier studies have indicated potential benefits of conservative oxygenation. Recent trials show contradictory results regarding mortality, organ dysfunction, and ventilatory-free days. Empirical studies comparing various targets for SaO2, or partial pressure of oxygen indicate a U-shaped curve balancing positive and negative effects of oxygen supplementation.

CONCLUSION AND FUTURE DIRECTIONS

To optimize risk-benefit ratio of resuscitation measures in critically ill patients with circulatory shock in addition to individual targets for CO and Hb concentration, a primary aim should be to restore tissue perfusion and avoid hyperoxia. In the future, an individualized approach with microcirculatory targets will become increasingly relevant. Further studies are needed to define optimal targets.

Lower or higher oxygenation targets in the intensive care unit: an individual patient data meta-analysis

PURPOSE

Optimal oxygenation targets for patients with acute hypoxemic respiratory failure in the intensive care unit (ICU) are not clearly defined due to substantial variability in design of previous trials. This study aimed to perform a pre-specified individual patient data meta-analysis of the Handling Oxygenation Targets in the ICU (HOT-ICU) and the Handling Oxygenation Targets in coronavirus disease 2019 (COVID-19) (HOT-COVID) trials to compare targeting a partial pressure of arterial oxygen (PaO2) of 8-12 kPa in adult ICU patients, assessing both benefits and harms.

METHODS

We assessed 90-day all-cause mortality and days alive without life support in 90 days using a generalised mixed model. Heterogeneity of treatment effects (HTE) was evaluated in 14 subgroups, and results graded using the Instrument to assess the Credibility of Effect Modification Analyses (ICEMAN).

RESULTS

At 90 days, mortality was 40.4% (724/1792) in the 8 kPa group and 40.9% (733/1793) in the 12 kPa group (risk ratio, 0.99; 95% confidence interval [CI] 0.92-1.07; P = 0.80). No difference was observed in number of days alive without life support. Subgroup analyses indicated more days alive without life support in COVID-19 patients targeting 8 kPa (P = 0.04) (moderate credibility), and lower mortality (P = 0.03) and more days alive without life support (P = 0.02) in cancer-patients targeting 12 kPa (low credibility).

CONCLUSION

This study reported no overall differences comparing a PaO2 target of 8-12 kPa on mortality or days alive without life support in 90 days. Subgroup analyses suggested HTE in patients with COVID-19 (moderate credibility) and cancer (low credibility).

Ventilator-Associated Pneumonia, Ventilator-Associated Events, and Nosocomial Respiratory Viral Infections on the Leeside of the Pandemic

The COVID-19 pandemic has had an unprecedented impact on population health and hospital operations. Over 7 million patients have been hospitalized for COVID-19 thus far in the United States alone. Mortality rates for hospitalized patients during the first wave of the pandemic were > 30%, but as we enter the fifth year of the pandemic hospitalizations have fallen and mortality rates for hospitalized patients with COVID-19 have plummeted to 5% or less. These gains reflect lessons learned about how to optimize respiratory support for different kinds of patients, targeted use of therapeutics for patients with different manifestations of COVID-19 including immunosuppressants and antivirals as appropriate, and high levels of population immunity acquired through vaccines and natural infections. At the same time, the pandemic has helped highlight some longstanding sources of harm for hospitalized patients including hospital-acquired pneumonia, ventilator-associated events (VAEs), and hospital-acquired respiratory viral infections. We are, thankfully, on the leeside of the pandemic at present; but the large increases in ventilator-associated pneumonia (VAP), VAEs, bacterial superinfections, and nosocomial respiratory viral infections associated with the pandemic beg the question of how best to prevent these complications moving forward. This paper reviews the burden of hospitalization for COVID-19, the intersection between COVID-19 and both VAP and VAEs, the frequency and impact of hospital-acquired respiratory viral infections, new recommendations on how best to prevent VAP and VAEs, and current insights into effective strategies to prevent nosocomial spread of respiratory viruses.

The association of arterial partial oxygen pressure with mortality in critically ill sepsis patients: a nationwide observational cohort study

BACKGROUND

Although several trials were conducted to optimize the oxygenation range in intensive care unit (ICU) patients, no studies have yet reached a universal recommendation on the optimal a partial pressure of oxygen in arterial blood (PaO2) range in patients with sepsis. Our aim was to evaluate whether a relatively high arterial oxygen tension is associated with longer survival in sepsis patients compared with conservative arterial oxygen tension.

METHODS

From the Korean Sepsis Alliance nationwide registry, patients treated with liberal PaO2 (PaO2 ≥ 80 mm Hg) were 1:1 matched with those treated with conservative PaO2 (PaO2 < 80 mm Hg) over the first three days after ICU admission according to the propensity score. The primary outcome was 28-day mortality.

RESULTS

The median values of PaO2 over the first three ICU days in 1211 liberal and 1211 conservative PaO2 groups were, respectively, 107.2 (92.0-134.0) and 84.4 (71.2-112.0) in day 1110.0 (93.4-132.0) and 80.0 (71.0-100.0) in day 2, and 106.0 (91.9-127.4) and 78.0 (69.0-94.5) in day 3 (all p-values < 0.001). The liberal PaO2 group showed a lower likelihood of death at day 28 (14.9%; hazard ratio [HR], 0.79; 95% confidence interval [CI] 0.65-0.96; p-value = 0.017). ICU (HR, 0.80; 95% CI 0.67-0.96; p-value = 0.019) and hospital mortalities (HR, 0.84; 95% CI 0.73-0.97; p-value = 0.020) were lower in the liberal PaO2 group. On ICU days 2 (p-value = 0.007) and 3 (p-value < 0.001), but not ICU day 1, hyperoxia was associated with better prognosis compared with conservative oxygenation., with the lowest 28-day mortality, especially at PaO2 of around 100 mm Hg.

CONCLUSIONS

In critically ill patients with sepsis, higher PaO2 (≥ 80 mm Hg) during the first three ICU days was associated with a lower 28-day mortality compared with conservative PaO2.

Conservative versus liberal oxygen therapy for intensive care unit patients: meta-analysis of randomized controlled trials

BACKGROUND

It remains unclear whether conservative oxygen therapy (COT) or liberal oxygen therapy (LOT) is more beneficial to the clinical outcomes of intensive care unit (ICU) patients. We systematically reviewed the efficacy and safety of conservative versus liberal oxygen therapy for ICU patients.

METHODS

We systematically searched PubMed, Embase, Web of Science, Scopus, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, MedRxiv, and BioRxiv for reports on randomized controlled trials (RCTs) that compared the effects of COT versus LOT on the clinical outcomes of ICU patients published in English before April 2024. The primary outcome was the mortality rate, secondary outcomes included ICU and hospital length of stay, days free from mechanical ventilation support (MVF), vasopressor-free time (VFT), and adverse events.

RESULTS

In all, 13 RCTs involving 10,632 patients were included in analyses. Meta-analysis showed COT did not reduce mortality at 30-day (risk ratio [RR] = 1.01, 95% confidence interval [CI] 0.94 to 1.09, I2 = 42%, P = 0.78), 90-day (RR = 1.01, 95% CI 0.95 to 1.08, I2 = 9%, P = 0.69), or longest follow-up (RR = 1.00, 95% CI 0.95 to 1.06, I2 = 22%, P = 0.95) compared to LOT in ICU patients. In subgroup analyses, no significant difference was observed between the two groups in terms of the different ICU, baseline P/F, and actual PaO2. In addition, COT did not affect ICU length of stay, hospital length of stay, or VFT, it only affected MVF days.

CONCLUSIONS

COT did not reduce all-cause mortality in ICU patients. Further RCTs are urgently needed to confirm the impact of COT strategy on specific populations.