Effectiveness of Diaphragmatic Function and Parasternal Intercostal Muscles Functions as Predictors for Successful Weaning From Mechanical Ventilation

Mechanical ventilation is a commonly used therapeutic strategy in the Intensive care unit (ICU) by providing adequate oxygenation and ventilation until improvement of the patient's condition.

Serious consequences usually follow prolonged mechanical ventilation (MV) such as barotraumas and ventilator-associated pneumonia.

On the other hand, early discontinuation of ventilation is associated with adverse cardiovascular events. Therefore, time of extubation should be anticipated properly.

Respiratory muscle dysfunction is one of the leading reasons for difficult to wean population.

There is growing evidence about the use of diaphragmatic ultrasound in evaluating both need for and weaning from mechanical ventilation. However, diaphragmatic ultrasound carry some drawbacks such as lack of echogenicity and difficult to examine left side.

Extra-diaphragmatic muscles (including parasternal intercostal muscles, scalene muscles, and sternocleidomastoid) act hand-in-hand with diaphragm to complete mechanical pump actions therefore in case of diaphragmatic dysfunction accessory respiratory muscles increase their work. This could be a possible compensatory mechanism.

Evidence support the use of parasternal intercostal muscles as a predictor of need and weaning from mechanical ventilation with perfect inter-observer reliability that could provide further details about respiratory capacity/load harmony.

We, therefore, decided to study ultrasound assessment of these muscles during weaning from MV in critically ill patients.