From the Guidelines
Volume control (VC) ventilation is the preferred mode for patients with acute respiratory distress syndrome (ARDS), as it allows for precise control of tidal volumes and minute ventilation, which is crucial in this patient population. This is based on the recommendations from the American Thoracic Society, European Society of Intensive Care Medicine, and Society of Critical Care Medicine, which suggest using lower tidal volumes (4–8 ml/kg predicted body weight) and lower inspiratory pressures (plateau pressure < 30 cm H2O) for patients with ARDS 1. In VC mode, the ventilator delivers a set tidal volume regardless of the pressure needed, making it useful for conditions requiring consistent minute ventilation.
Some key considerations when deciding between VC and pressure control (PC) ventilation include:
- Patient's lung mechanics: VC is suitable for patients with stable respiratory mechanics, while PC is better for those with varying compliance or high peak pressures.
- Underlying pathology: VC is useful for conditions like ARDS or neuromuscular disorders, while PC may be more suitable for patients with COPD or asthma.
- Ventilation goals: The decision between VC and PC should be individualized based on the patient's specific needs and goals.
It's essential to note that the choice between VC and PC ventilation should be based on the patient's specific condition and ventilation requirements, and regular reassessment is necessary as patient needs may change throughout their course of mechanical ventilation. The most recent and highest-quality study recommends targeting lower tidal volumes and inspiratory pressures to improve patient outcomes 1.
From the Research
Volume Control vs Pressure Control Ventilation
The decision to use volume control (VC) versus pressure control (PC) ventilation on a ventilator depends on various factors, including the patient's condition and the desired outcome.
- Volume-controlled ventilation (VCV) offers the safety of a pre-set tidal volume and minute ventilation, but requires the clinician to appropriately set the inspiratory flow, flow waveform, and inspiratory time 2.
- Pressure-controlled ventilation (PCV) limits the maximum airway pressure delivered to the lung, but may result in variable tidal and minute volume 2.
- PCV may offer lower work of breathing and improved comfort for patients with increased and variable respiratory demand 2.
- In patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS), PCV significantly reduced patient work of breathing relative to VCV 3.
Patient-Specific Considerations
- For patients who are not breathing spontaneously, PCV offers no advantage over VCV, especially when decelerating flow is available during VCV 2.
- In patients at high risk for acute respiratory distress syndrome, a strategy of mechanical ventilation that limits peak inspiratory pressure and tidal volume does not appear to reduce mortality and may increase morbidity 4.
- Pressure-limited ventilation can be used safely and is well tolerated as an initial mode of ventilatory support in patients with acute hypoxic respiratory failure 5.
Ventilatory Modes
- The choice between VC and PC ventilation should be based on the individual patient's needs and response to therapy 6.
- Dual-control modes, which are volume-targeted, pressure-limited, and time-cycled, may combine the beneficial characteristics of both VCV and PCV 2.
- The use of pressure-limited ventilation is associated with lower peak airway pressure and more rapid improvement in static thoracic compliance than volume-controlled ventilation 5.