High frequency ventilation is a mechanical ventilation technique which utilizes a high frequency and low tidal volume. The ventilator is set to breathe more times per minute than a person would independently, and the amount of air pushed into the lungs is lower than that which would normally be pulled in with a normal breath. There are some advantages to high frequency ventilation which can make it a useful tool for providing ventilation to patients who cannot breathe independently.
Several different ventilation techniques are used in high frequency ventilation, including jet ventilation, oscillatory ventilation, and positive pressure ventilation. In all cases, the patient is on a mechanical ventilator because the patient cannot breathe on his or her own. Patients often wind up on ventilators when they are in the intensive care unit, and ventilators can be key to supporting patients while they recover. However, they can also be dangerous; patients can develop lung damage during prolonged ventilator use, for example, and this is when high frequency ventilation can be useful.
This type of ventilation reduces the risk of barotrauma, or damage to the lungs, significantly. It can be used in patients of all ages, and can be especially useful for premature infants with lungs which are not completely formed yet. High frequency variation effectively keeps the lung open, reducing the amount of inflation and deflation which occurs, along with lowering pressure variations, which can protect the lungs from damage.
Studies have suggested that gas mixing and gas exchange under high frequency ventilation can be better than those under other forms of mechanical ventilation. Like other forms of ventilation, high frequency violation can impact the heart rate, and cause the patient to retain fluids. It is also possible to cause barotrauma with this ventilation technique, making it important to check the ventilator settings and monitor the patient while he or she is on the ventilator.
This type of mechanical ventilation may be recommended if a patient is not doing well on a conventional ventilator, or if a patient is at risk of lung damage while on a ventilator. Doctors may also switch to high frequency ventilation if the settings on a conventional ventilator must be dangerously high for the patient's oxygen level to be satisfactory.
There are some risks to switching to high frequency ventilation. Some patients do not do well with this type of mechanical ventilation, in which case changing ventilators could cause them to go into a decline. The types of ventilators used are also harder to work around because the tubing is stiffer, which can be a problem for nurses and other support staff.