ATC vs PSV for Weaning in Patients With Respiratory Failure

Mechanical ventilation is a cornerstone in the management of patients with acute respiratory failure, but prolonged dependence on the ventilator is associated with increased morbidity, mortality, and healthcare costs. Weaning, the process of transitioning a patient from mechanical ventilation to spontaneous breathing, is a critical phase that requires careful timing and appropriate methodology. The spontaneous breathing trial (SBT) is a widely used tool to assess weaning readiness, and several ventilatory modes have been developed to optimize this step. Among these, Automatic Tube Compensation (ATC) and Pressure Support Ventilation (PSV) are two commonly applied modes, each with distinct physiological principles.

ATC is designed to compensate precisely for the resistance imposed by the endotracheal tube, aiming to reproduce the normal work of breathing as if the patient were breathing without the artificial airway. In contrast, PSV provides a fixed level of pressure support throughout inspiration, which assists respiratory muscles and reduces the work of breathing but may not adapt dynamically to changes in flow or resistance. Although both modes are frequently used in intensive care units, evidence comparing their effectiveness in facilitating weaning and extubation success has been variable, with some studies suggesting physiological advantages of ATC but limited data on clinical outcomes.

his prospective randomized clinical trial was conducted to address this gap by directly comparing ATC and PSV as SBT modes in adult patients with acute respiratory failure receiving invasive mechanical ventilation. Patients were screened for weaning readiness using standardized clinical and physiological criteria and were subsequently randomized to undergo SBT with either ATC or PSV. Interventions were delivered following established ICU protocols to ensure safety and uniformity across groups.

Throughout the study, key respiratory and gas exchange parameters were monitored before and after the SBT to assess physiological responses to the two modes. Extubation decisions were based on predefined criteria to minimize variability in clinical judgment. Patients were followed for early post-extubation outcomes to evaluate the clinical impact of each mode on weaning success. The primary endpoint focused on improvement in oxygenation, while secondary endpoints included respiratory mechanics and post-extubation outcomes. The study adhered to ethical regulations, with written informed consent obtained prior to enrollment. By providing a structured comparison of these two modes, the study contributes to the evidence guiding optimal weaning strategies in adult critically ill patients, potentially improving clinical outcomes and optimizing ICU resource utilization.

Statistical analysis was performed using SPSS software (version 16.0; IBM Corp., Armonk, NY, USA). The required sample size was calculated a priori to provide 80% power to detect a clinically meaningful difference in the primary outcome at a two-sided significance level of 0.05. Continuous variables were expressed as mean ± standard deviation and compared between groups using appropriate parametric tests. Categorical variables were presented as frequencies and percentages, and analyzed using the Chi-square test or Fisher's exact test as indicated. A P value < 0.05 was considered statistically significant. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curve analysis, with calculation of sensitivity, specificity, positive predictive value, and negative predictive value.

The results of this completed study provide valuable clinical evidence regarding the optimal mode of spontaneous breathing trials in adult patients with acute respiratory failure. By comparing ATC and PSV, the study highlights differences in physiological responses and clinical outcomes between the two modes. These findings can help refine weaning protocols, support clinical decision-making, and contribute to improving extubation success rates and patient outcomes in intensive care settings. Moreover, the results may serve as a reference for future research and guideline development, particularly in resource-limited environments.

Inclusion criteria

• Age ≥18 years.
• Admitted with acute respiratory failure (ARF).
• On mechanical ventilation with Puritan-Bennett 840 ventilator for ≥24 hours.
• Considered for weaning after improvement or resolution of underlying cause.
• Fully conscious.
• Minimal or no requirement for vasoactive drugs or sedation.
• Adequate gas exchange (PaO₂/FiO₂ >200 at PEEP 5 cmH₂O and FiO₂ <0.5) Rapid shallow breathing index (RSBI) <105 breaths/min/L.

Exclusion criteria

• Age <18 years.
• Pre-existing chronic obstructive pulmonary disease (COPD).
• Neuromuscular disorders.
• Hemodynamic instability requiring high-dose vasoactive support.
• Persistent altered level of consciousness.
• Ongoing sedation.
• Severe metabolic or electrolyte disturbances.
• Morbid obesity (BMI ≥40 kg/m²).
• Tracheostomy.
• Pregnancy.
• Refusal to participate by patient or legal guardian.