The Role of Mechanical Ventilation in ARDS Management

Mechanical ventilation is a crucial component of ARDS management, as it provides support for the patient's breathing while minimizing the risk of ventilator-induced lung injury (VILI). In this article, we will explore the role of mechanical ventilation in ARDS management.

What is Mechanical Ventilation?

Mechanical ventilation is a medical intervention that provides respiratory support to patients who are unable to breathe adequately on their own. It involves using a machine that delivers oxygen-rich air to the patient's lungs through a tube inserted into their airway.

In ARDS, mechanical ventilation is essential in managing the patient's respiratory failure. The goal of mechanical ventilation in ARDS is to improve oxygenation while minimizing the risk of VILI.

Lung Protective Ventilation Strategy

A lung-protective ventilation strategy is the preferred approach to mechanical ventilation in patients with ARDS. This strategy involves using low tidal volumes and positive end-expiratory pressure (PEEP) to minimize the risk of VILI.

Tidal volume refers to the volume of air delivered to the lungs with each breath. In ARDS, using a low tidal volume of 6 ml/kg of predicted body weight is recommended. This helps to prevent overdistension of the lungs, which can cause further damage.

PEEP is a constant pressure applied to the airway at the end of expiration to keep the lungs open. In ARDS, using a higher PEEP can help to recruit collapsed alveoli and improve oxygenation. However, using excessive PEEP can cause lung overdistension, leading to VILI. Therefore, the optimal PEEP level is determined based on the patient's individual needs.

Ventilator Settings

Adjusting the ventilator settings is crucial in optimizing oxygenation and minimizing the risk of VILI in ARDS patients. The following ventilator settings are commonly adjusted in ARDS management:

1. FiO2: FiO2 refers to the fraction of inspired oxygen delivered to the patient. In ARDS, starting with a high FiO2 is necessary to achieve adequate oxygenation. However, using excessive FiO2 can cause oxygen toxicity. Therefore, the FiO2 is gradually weaned down to maintain an oxygen saturation of 88-95%.

2. Respiratory rate: Respiratory rate refers to the number of breaths delivered per minute. In ARDS, a lower respiratory rate is preferred to minimize the risk of VILI.

3. Inspiratory flow rate: Inspiratory flow rate refers to the speed at which the ventilator delivers the breath. In ARDS, using a slower inspiratory flow rate can improve gas distribution and minimize the risk of VILI.

4. Plateau pressure: Plateau pressure refers to the pressure in the lungs at the end of inspiration. In ARDS, keeping the plateau pressure below 30 cmH2O is recommended to prevent overdistension of the lungs.

Prone Positioning

In severe ARDS cases, prone positioning is recommended as an adjunct therapy to mechanical ventilation. Prone positioning involves turning the patient onto their stomach, which helps to redistribute lung perfusion and improve oxygenation.

Prone positioning has been shown to improve oxygenation and reduce mortality in patients with severe ARDS. However, prone positioning can cause complications such as pressure ulcers and airway obstruction, and should be carefully monitored.

Complications of Mechanical Ventilation

Mechanical ventilation is not without risks. VILI, barotrauma, and ventilator-associated pneumonia (VAP) are some of the complications associated with mechanical ventilation in ARDS patients.

VILI is a form of lung injury caused by excessive tidal volumes, high inspiratory pressures, and repeated opening and closing of