Weaning patients from the ventilator in the intensive care unit is sometimes difficult because of three main interrelated etiologies: impaired lung, heart or diaphragm function. In this context, ultrasonography performed during tests for extubation of patients may enable the diagnosis of cardiac dysfunction, loss of pulmonary aeration, diaphragm dysfunction, and venous congestion, thereby reducing the number of failures in extubation.

The combination of TTE (Trans Thoracic Echocardiography), LUS (Lung Ultrasound), DUS (Diaphragmatic ultrasound) and VEXUS (Venous excess Ultrasound) may enable the identification of the etiology of weaning failure and reduce the number of extubation failures by enabling the development of an appropriate treatment strategy. With this study, it is aimed to contribute to the literature in this sense.

The aim of this study is to reduce the number of extubation failures by defining the etiology of weaning failure and developing appropriate treatment strategies by using intensive care ultrasonography applications in combination (defining cardiac, pulmonary, diaphragmatic and venous congestion).

Most patients can be extubated after the first SBT (spontaneous Breathing Trial). A patient who fails extubation is automatically classified as difficult weaning, and intensive care professionals frequently encounter patients who are difficult to wean from mechanical ventilation.

Before performing a new SBT following a failed SBT, the cause of the failure should be determined and an appropriate treatment strategy developed.

Inclusion Criteria:

• Invasive mechanical ventilation > 24 hours Eligibility to weaning from mechanical ventilation

Exclusion Criteria:

• Age < 18 years old
• Severe skin lesions or infections that cannot perform ultrasound
• Severe subcutaneous emphysema that cannot perform ultrasound
• Patients with a known neuromuscular disease
• Patients with a duration of mechanical ventilation <24 hours,
• Patients with severe mitral stenosis, severe mitral regurgitation, or prosthetic mitral valve

The researchers aimed to predict the success and failure of extubation and measure the associated ultrasound indices with the combined ultrasound-guided weaning protocol in all critically ill patients over the age of 18 who remain on mechanical ventilator for more than 24 hours and are thought to be ready for weaning. Evaluations will be made just before the spontaneous breathing trial and at the end of the spontaneous breathing trial in critically ill patients undergoing mechanical ventilation.