INFANT STAR HFV/IMV TECHNIQUE

Insure that the oscillator on/off toggle switch is in the off position
Adjust the amplitude completely full counterclockwise
Rotate the mechanical pop-off full clockwise
Turn the key/lock mechanism to the on position
set the frequency to 10-15 Hz
record the Paw seen in the monitoring window labeled mean
turn the on/off toggle switch to the on position
increase the amplitude until the patient's chest vibrates visually
at this fixed amplitude, reduce the IMV rate by one half
increase the PEEP level to compensate for the drop in Paw caused by the reduction in mechanical rate until the Paw post initiation of HFV is the same as the pre-HFV value recorded in step 6
HOLD the above settings for 15-30 minutes observing the patient monitors for oxygenation and ventilation and get ABG if indicated
if the PCO2 continues to drop reduce the imv rate in increments of 2-5 until ten breaths per minute is reached. Let the Paw now fall with the changes in rate. In general the I-time can be adjusted in the range of 0.2-0.8 sec. During HFV the IMV breaths may not result in the same degree of chest excursion as in the IMV only mode. This is due to a lower variation around a mean lung volume. DO NOT attempt to compensate for this reduced chest movement with more PIP because the pulmonary parenchyma can readily over-distend and worsen the air leak
as further reduction in rate can be made, do so by one b/m with a final minimum rate of 2-5, always monitor the oxygenation, ventilation and xrays.

WARNING-when initiating and maintaining HFV patients, be sure to adhere to the following:

it is highly recommended that skin surface monitoring be available at all times for trending purposes of both CO2 and O2
DO NOT USE the mechanical pop-off as the primary pressure limiting device for IMV breaths. By doing so amplitude (energy) may bleed out the pop off.
MEAN AIRWAY PRESSURE (Paw) is the primary monitoring parameter for oxygen
AO ALARMS are indicative of an INCOMPATIBLE CIRCUIT OR BLOCKAGE causing high resistance . Clear blockage or replace with patient circuit of at least 10mm id.
HFV AMPLITUDE is the preferred method of maintaining PaCO2 levels. Paw via PEEP/CPAP is the preferred method of maintaining PaO2 parameters.
PEEP/CPAP levels will often be HIGHER than on conventional mechanical ventilation. It is not unusual to utilize baselines greater than 10-15 cmH2O. As long as Paw is acceptable and PaO2 is adequate, DO NOT worry about high levels of PEEP/CPAP unless the cardiovascular system is being impaired.

HFV-ONLY TECHNIQUE OF INITIATING HIGH FREQUENCY

While in the conventional IMV mode, check the Infant Star monitoring window and record the Paw.
Insure that the ON/OFF toggle switch is in the OFF position
Adjust the AMPLITUDE knob completely full COUNTERCLOCKWISE.
Rotate the mechanical pop-off full CLOCKWISE
Turn the KEY/LOCK mechanism to the ON POSITION.
Seth the FREQUENCY to 10-15Hz.
Turn the ON/OFF toggle switch to the ON position
INCREASE THE AMPLITUDE until the patient's chest vibrates visually
At this amplitude, turn the IMV MODE control to the CPAP DEMAND MODE. The IMV rate will now stop and the patient is on HFV-ONLY.
INCREASE the CPAP level to compensate for the drop in Paw caused by the elimination of mechanical IMV breaths until the Paw post initiation of HFV is the same as the pre-HFV value recorded. It is not unusual for PEEP/CPAP levels to be in the “teens”.
HOLD the above settings for 15-30 minutes observing the patient monitors for oxygenation and ventilation. Obtain an arterial blood gas and chest x-ray if indicated.
If the PCO2 continues to drop and the PO2 is maintained or improved, STOP at these HFV settings. Should there be any question as to the effectiveness of HFV-ONLY, DO NOT hesitate to return to the conventional IMV MODE.

HFV/IMV WEANING:

In general, the infant is ready to come off HFV when the IMV rate is less than 10/min; the Paw is less than 10cmH2O and FIO2 is less than .40.
When the time is appropriate as noted above. LEAVE THE FREQUENCY ALONE and start weaning back slowly on the HFV AMPLITUDE in increments of 2-5cm H2O until the CO2 begins to rise. The infant's spontaneous respirations at this point are unable, with a lower HFV, to remove CO2 effectively.
OBTAIN an arterial blood gas to validate the skin surface monitoring devices. Once the PaCO2 is at the clinically desired limit, STOP reducing the amplitude.
REDUCE the PEEP to the baseline considered normal for IMV-ONLY support. DO NOT drop below 3 cmH20. A slight increase in mechanical rate may be necessary at this time.
The duration of weaning is dependent upon the patient. While maintaining the established CO2 reference, lower the amplitude slightly. If the CO2 remains unchanged, either the infant's respirations are effective or HFV is partially assisting.
REDUCE the Paw to at least 5 cmH2O. The FIO2 should also be weaned down to at least .40. Continue to REDUCE the AMPLITUDE until a CO2 rise occurs or until the amplitude is at its lowest position.
TURN-OFF the HFV toggle switch. The infant is now on low IMV ONLY

HFV-ONLY WEANING:

In general, the patient is ready to come off HFV-ONLY when the Paw is less than 10cmH2O and the FIO2 is less than .40
When the weaning time is appropriate. LEAVE THE FREQUENCY ALONE and start weaning back slowly on the AMPLITUDE in increments of 2-5 cmH2O until the CO2 begins to rise. The infant's spontaneous respirations at this point are unable, with a lower HFV, to remove CO2 effectively.
OBTAIN an arterial blood gas to validate the skin surface monitoring devices. Once the PaCO2 is at the desired clinical limit. STOP reducing amplitude.
REDUCE the CPAP to the baseline considered normal for CPAP-ONLY support. DO NOT reduce lower than 3 cmH2O.
The duration of weaning is determined by the patient. While maintaining an established CO2 and O2 reference, continue reducing AMPLITUDE. If the CO2 remains unchanged, either the infant's spontaneous respirations are sufficient to maintain ventilation or HFV is still partially assisting.
REDUCE the Paw to at least 5-10cm H2O. The FIO2 should be reduced to at least 0.40. CONTINUE to reduce amplitude until a CO2 rise occurs or until the amplitude is at its lowest position.
TURN OFF the HFV. The infant is now on CPAP only.