High-frequency artificial lung ventilation/SH (nurse)

High-frequency ventilation (HFO) is a non-conventional type of artificial lung ventilation. Ventilation of the patient's/client's lungs takes place with small breathing volumes at high frequency. Small tidal volumes combined with high frequency ensure minimal fluctuations in airway pressures and volumes, resulting in a reduced risk of lung injury.
 * In conventional artificial lung ventilation, we calculate the minute volume (MV) by multiplying the respiratory rate by the tidal volume, from which we must subtract the volume of dead space present in the airways.
 * → MV = f x (Vt&minus;Vd).


 * For HFO MV, we calculate by multiplying the frequency by the tidal volume squared → MV = f x Vt2.

Indications

 * ARDS (Acute Respiratory Distress Syndrome).
 * Congestive lung.
 * Newborns.

Contraindications

 * Chronic obstructive pulmonary disease (COPD).
 * Status asthmaticus.
 * Pulmonary emphysema.
 * Intracranial hypertension.

HFO modes

 * HFPPV = high frequency positive pressure ventilation; f=60-100 cycles/min.
 * - this frequency can also be achieved on a conventional ventilator.


 * HFJV = high frequency jet ventilation; f=80-600 cycles/min.
 * - the breathing mixture is forced under high energy into the patient's airway by a jet.


 * HFALV = high frequency alternating pressure ventilation; f= 120-400 cycles/min.
 * HFOV = high frequency oscillatory ventilation; f=180-900 cycles/min.

Parametry HFO

 * Frequency of breaths given in Hz (1Hz = 60 breaths).
 * Amplitude (7–130 cmH2O).
 * Inspiration Time (30–50 % cyklu).
 * mPaw (5–55 cm H2O).

HFO design

 * Ensuring DC patency - oro- or naso-tracheal intubation, tracheostomy.
 * Deep sedation and relaxation of the patient/client.
 * We do not suction the patient/client.
 * Regular X-ray checks.
 * HF fan requirements:
 * High reliability and durability.
 * Ability to deliver a given breathing mixture, FiO2 21-100%.
 * Provision of DC humidification.
 * DC pressure monitoring, alarm activation and ventilation shutdown at critical pressure.

Patient/client monitoring

 * Monitor physiological functions (BP, P, SpO2, CVP, TT, GCS, etc.).
 * We perform arterial ASTRUP just before starting HFO, then 10 minutes after starting and then 1 h according to the doctor's orders and on the following days at least 3 times a day.
 * Monitor and record values on the fan.
 * We observe the symmetry of vibration from the collarbones to the thighs.

Disadvantages of HFO

 * Noise, deterioration of climatic conditions around the bed.
 * Difficult physical examination of the patient.
 * More difficult positioning of patients.
 * Cannot provide "weaning".
 * HFO is a problem during patient transport.
 * Negative family perception.

Side effects of HFO

 * Decrease in BP.
 * Formation of mucus plugs.
 * Increasing intraluminal pressure.
 * Barotrauma.

Fan care

 * The ventilation circuit is disposable, but can be sterilized in a plasma sterilizer.
 * Alcohol and solvents must not be used on external surfaces.
 * Do not place anything on top of the fan.
 * The temperature sensor is disinfected with alcohol disinfection.

References used

 * Interpretation MUDr. Lukáše Pokorného
 * Interpretation MUDr. Lukáše Pokorného