European Journal of Cardiovascular Medicine

Mechanical ventilation is a vital intervention that alleviates respiratory distress and corrects hypoxemia and acute respiratory acidosis, presenting significant challenges for physicians in the ICU. Weaning from mechanical ventilation is a critical step in the management of patients recovering from respiratory failure [1]. It involves the gradual reduction of ventilator support, ultimately leading to extubation and the restoration of spontaneous breathing. However, approximately 30% of patients experience challenges in the weaning process [2] . Nearly 40% of a patient's time on mechanical ventilation is spent on the weaning process, underscoring its critical role in ICU management while posing a significant demand on resources [3]. Spontaneous Breathing Trials (SBTs) serve as the primary method for assessing a patient's readiness for weaning, traditionally performed using T-piece ventilation or low-level pressure support [4].

T-piece trials, practiced for decades, allow patients to breathe spontaneously without ventilator support and are considered to simulate post-extubation conditions [5]. However, the T-piece method can be associated with increased work of breathing and patient discomfort, potentially leading to trial failure or reintubation [6]. Recently, high-flow oxygen therapy (HFOT) has emerged as a promising alternative to deliver heated, and humidified oxygen at high flow rates up to 60 L/min. HFOT enhances oxygenation, reduces dead space, and provides minimal positive end-expiratory pressure (PEEP), thereby facilitating a smoother weaning transition [7,8].

Despite increasing interest in HFOT, evidence comparing its efficacy to traditional T-piece systems during the weaning phase remains limited. Studies have shown mixed outcomes regarding reintubation rates, ICU stay, and patient comfort, indicating a need for further investigation in diverse clinical settings [8,9]. This study aims to evaluate and compare the outcomes of high-flow oxygen with T-piece ventilation among patients receiving mechanical ventilation, primarily intubated for respiratory distress or low Glasgow Coma Scale (GCS), during the wean-off phase.

Study design and participants

This study was a randomized prospective, double-blinded controlled trial conducted between July 2023 and January 2025 in the Critical Care Unit (ICU) of BLDE, Shri B.M. Patil Medical College, Hospital and Research Centre, Vijayapura. Consecutive patients aged above 18 years with respiratory distress who received mechanical ventilation for at least 12 hours were screened. Written informed consent was taken from all patients or their legal surrogates.

Inclusion and exclusion criteria

Patients (aged above 18 years) who had received mechanical ventilation for a minimum duration of 12 hours were eligible and patients with tracheostomy, unwilling to continue life support, or intubated for over one month were excluded.

Sample size calculation

Using G*Power version 3.1.9.4 software, the sample size was calculated based on the comparison of lactate levels in the T-piece SBT group (mean = 1.9, SD = 0.8148) and the high-flow oxygen SBT group (mean = 1.4, SD = 0.8148). To achieve a power of 89% and a significance level of 5% for detecting a difference in means between two independent groups (t-test), the required total sample size was 110 patients, with 55 patients in each group.

Randomization and group allocation

Patients were randomized in a 1:1 ratio into two groups using a sealed opaque envelope technique. Group A received high-flow nasal cannula (HFNC) oxygen therapy and Group B received T-piece ventilation. Randomization was performed by the physician, and the allocation envelope was selected by the attending nurse.

Intervention protocol

Patients in the T-piece group were disconnected from the ventilator and connected to a T-piece device powered by an air entrainment nebulizer, which provided an FiO₂ of 0.4 at a flow rate of 8 L/min. In the high-flow group, ventilator settings were adjusted to inbuilt high-flow oxygen mode with FiO₂ set at 0.4 and flow at 60 L/min.

Spontaneous breathing trial (SBT) and monitoring

All patients underwent an SBT for 30 – 60 minutes or until signs of clinical intolerance. The FiO₂ was maintained at 0.4 in both groups to ensure uniform oxygenation levels. Each patient was examined for arterial blood gas (ABG) analysis, heart rate, oxygen saturation, and mean arterial pressure.

Post-SBT protocol

Patients who completed the SBT were reconnected to mechanical ventilation with their previous settings for a one-hour rest period, followed by direct extubation. If a patient failed the SBT, they were returned to mechanical ventilation and reassessed with daily SBTs using the same assigned method. Failure to pass SBT within 72 hours of the initial attempt was classified as a weaning failure. The use of prophylactic HFNC, pressure support (PS), or non-invasive ventilation (NIV) post-extubation for at least 48 hours was allowed based on physician discretion but was not protocolized.

Ethical Consideration

All participants or their legal surrogates provided written informed consent. The trial protocol was approved by the Institutional Ethics Committee (Ref. No: BLDE(DU)/IEC/948/2023-24) for ethical clearance and registered under the Clinical Trial Registry of India (CTRI/ 2023/ 07 /055168). Then the study was started.

Statistical Analysis

Data were analyzed using SPSS version 26. Continuous variables were expressed as mean ± SD and compared using the independent t-test. Categorical variables were analyzed using the chi-square (ꭓ²) test or Fisher’s exact test. A p-value < 0.05 was considered statistically significant. The primary outcome was weaning failure within 48 hours; secondary outcomes included ICU stay duration and post-extubation ABG changes.

Mechanical ventilation is a common intervention in the ICU for patients who cannot maintain adequate oxygenation. Prolong use of mechanical ventilation is costly and carries risks, making timely weaning and extubation critical. However, determining the right moment to discontinue ventilation is complex and prone to errors, with some patients being extubated too soon and others kept on support unnecessarily. This situation leads to complications and may affect clinical outcome. To address this challenge, various criteria have been developed to assess readiness for weaning and reduce risks.

This study was carried out on 110 patients suffering from respiratory distress with an age range from 18 to 70 years. A statistically significant difference was observed in the length of ICU stay between the two groups. Patients weaned using high-flow oxygen therapy had shorter ICU stays compared to those managed with the T-piece method. Additionally, post-extubation arterial blood gas (ABG) values showed significant improvements in the high-flow group, whereas the T-piece group demonstrated no statistically significant changes. The weaning method was also found to be significantly associated with the reason for intubation. Table 1 demonstrates the comparison of the length of ICU stay and duration of mechanical ventilation between patients in the high-flow oxygen (HFO) and T-piece groups, revealing a significant reduction in ICU stay in the HFO group.

Table 1: Comparison of ICU stay and mechanical ventilation duration between study groups

Patients in the HFO group had significantly shorter ICU stays (5.47 vs. 7.29 days, p = 0.019), indicating earlier recovery and discharge readiness compared to the T-piece group. Table 2 shows the within-group comparison of arterial blood gas parameters in the HFO and T-piece groups before and after extubation. The HFO group showed significant improvements in pH, PaO₂, and PaCO₂, while the T-piece group showed no significant changes.

Table 2: Arterial blood gas (ABG) changes before and after extubation within each group

Improvement in post-extubation PaO₂ and PaCO₂ in the HFO group was statistically significant (p < 0.05), suggesting better oxygenation and ventilation dynamics after extubation. Table 3 presents a direct comparison of post-extubation ABG parameters between the two groups, further underscoring the superior efficacy of the high-flow method in optimizing oxygenation.

Table 3: Comparison of post-extubation ABG parameters between groups

Significantly higher post-extubation PaO₂ (p = 0.014) and PaCO₂ (p = 0.013) in the HFO group indicate improved gas exchange and ventilatory adaptation. A statistically significant association was observed between the method of weaning and the primary reason for intubation (p = 0.000). Patients intubated due to dyspnea were more likely to be weaned using high-flow oxygen, whereas those with low GCS were predominantly managed with the T-piece method.

The present study evaluated the outcomes of high-flow oxygen therapy and T-piece ventilation in patients undergoing spontaneous breathing trials (SBTs) during the weaning phase from mechanical ventilation. The findings suggest that high-flow oxygen (HFO) offers significant advantages in terms of respiratory stability, patient comfort, and reduced reintubation rates compared to the traditional T-piece method. High-flow oxygen has gained attention as a non-invasive respiratory support strategy that delivers heated and humidified oxygen at high flow rates, improving oxygenation, reducing anatomical dead space, and providing a small degree of positive airway pressure [10,11]. Several clinical trials have demonstrated that HFO facilitates more comfortable breathing and reduces the work of breathing during the weaning process [12, 13]. Our study aligns with these findings, showing that patients in the HFO group had fewer complications, improved tolerance, and better weaning success.

In contrast, the T-piece method, while effective in simulating post-extubation conditions, may impose greater respiratory workload and discomfort, especially in patients with marginal respiratory reserve [13]. The increased respiratory effort required during T-piece trials may predispose some patients to weaning failure or reintubation, as observed in a subset of our T-piece cohort. Our results are consistent with previous randomized trials that support the use of HFO in post-extubation management. Hernández et al. found that high-flow oxygen significantly reduced the risk of reintubation and respiratory failure after planned extubation in high-risk patients compared to conventional oxygen therapy [14]. Similarly, Maggiore et al. reported enhanced oxygenation and comfort in patients receiving HFO compared to T-piece trials [15].

Despite these promising findings, it is important to note that weaning strategies must be individualized. Patient factors such as the underlying cause of mechanical ventilation, comorbidities, and respiratory mechanics play a crucial role in determining the appropriate SBT modality. While HFO may be particularly beneficial in patients recovering from hypoxemic respiratory failure, others may still respond well to T-piece trials. Limitations of our study include the single-center design and a relatively small sample size, which may affect the generalizability of the results. Additionally, long-term outcomes such as ICU length of stay and mortality were not the primary focus of this analysis. Further multicenter studies with larger cohorts are warranted to validate our findings and optimize SBT protocols.

This study demonstrates that both high-flow oxygen therapy and T-piece ventilation are viable strategies for conducting spontaneous breathing trials during the weaning phase from mechanical ventilation. However, patients managed with high-flow oxygen showed more favorable outcomes in terms of respiratory stability, reduced reintubation rates, and improved tolerance to weaning. These findings suggest that high-flow oxygen may offer a more effective and patient-friendly alternative in specific clinical scenarios, particularly in individuals initially intubated for respiratory distress or altered consciousness. While both modalities hold clinical relevance, individualized assessment remains crucial. Future larger-scale, multicentric trials are warranted to validate these results and guide standardized weaning protocols in intensive care settings.

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