INTRAPULMONARY PERCUSSIVE VENTILATION (IPV)


THEORY OF OPERATION

IPV combines percussive high rate positive pressure intermittent ventilation, CPAP, high density aerosol, medications and internal chest physiotherapy into a compact 15 to 20 minute treatment.

GOALS OF THERAPY

  1. Alveolar recruitment/ventilation to establish an effective blood gas interface.
  2. Effective resolution of atelectasis.
  3. Mobilization of retained endobronchial secretions.

IPV is able to accomplish therapeutic goals due to device entitled the phasitron. It is a combination venturi exhalation valve positioned at the proximal airway to regulate the flow of gases from the IPV unit to conform to pressures developing within the lungs. This is accomplished through the movement of the sliding venturi within the body of the phasitron. The flow of inspiratory gas is augmented by ambient entrainment of room air. When the IPV is driven by oxygen the approximate FIO2 varies between forty to fifty percent. The forward movement of the venturi is factored by the pressure developed within the airways due to retained secretions, mucosal and submucosal edema, and spasming of terminal bronchioles. This delivery of stacked percussive aerosol laden gases enables IPV therapy to overcome “preferential airways” and achieve alveolar ventilation.

The inspiratory phase of therapy combines aerosol, medications, and percussion controlled by a precise I/E ratio ( 1 to 2.5 ) and a wedge (CPAP) pressure that holds the airways open throughout the cycle. Gas is constantly exchanged through the expiratory port of the phasitron due to movement of the sliding venturi. The term “fluidic clutching,” describes movement of the sliding venturi as it responds to obstructions within the airways. When the flow of inspiratory gas and lung pressures equalize inspiration can be continued without increasing peak airway pressures. It is believed that at this time distal airway pressure approximates proximal pressures resulting in very effective ventilation. Percussion, aerosol, and medications continue to be administered. This portion of inspiration is termed “oscillatory equilibrium.”

SECRETION MOBILIZATION

The thorough rapid recruitment of the lungs combined with the adhesive forces holds the retained secretions in place while they are liquified and loosened. During the expiratory phase gases below the secretions move upwards towards the proximal airway sweeping the loosened secretions along.

Thin secretions-when adhesive forces are greater the cohesive forces- allows IPV to breech secretions to achieve lung recruitment. The adhesive forces of the secretions hold them into place while they are being hydrated and percussed.

When cohesive force is greater than adhesive force ( thick secretions ) gas flows around the retained secretions to achieve recruitment.

*NOTE: When treating patients with poor cough reflex, the therapist should rotate the frequency control from easy towards hard to find the proper resonant frequency to mobilize retained secretions. If this is not accomplished the frequency control should be returned to easy and the respirator drive pressure should be raised several PSI and the procedure repeated.

*CAUTION*
Patients with retained secretions, chronic hypoventilation, and an inability to cough effectively will normally require active suctioning and possible placement in drainage positioning.

 POSSIBLE CLUES:

  1. Drop in oxygen saturation.
  2. Brief periods of third degree AV heart block with associated
    hypoxemia.

The retained secretions and plugged areas are effectively percussed and liquified and secretions can be redeposited in the larger airways leading to the mentioned situations.

CLINICAL APPLICATIONS

  1. Chronic Obstructive Pulmonary Disease:
    1. Cystic Fibrosis
    2. Bronchitis
    3. Asthma
    4. Bronchiectasis
    5. Emphysema
  2. Neuromuscular Disorders
  3. Post Operative:
    1. Heart surgeries
    2. Lung Transplants
  4. Smoke Inhalation
  5. Pneumonia
  6. Immobilized Ciliary Syndrome
  7. Atelectasis
  8. Effects of Pulmonary Edema
  9. Drowning Victims

POSSIBLE CONTRAINDICATIONS

  1. Fresh blood- discontinue therapy until the problem is resolved. Dried darkened blood has probably been retained and the aerosol and percussion action have loosened it.
  2. Unresolved Pneumothorax- can proceed with caution in this situation by utilizing a low drive pressure, rapid frequency, and by creating a leak at the phasitron by disconnecting the red manometer line.
  3. Fractures of ribs- alveolar recruitment is thorough in most situations and in this instance could create a pneumothorax or pneumothoraces
  4. Pulmonary Embolus- percussive action may dislodge and move emboli
ASSEMBLY OF BREATHING CIRCUIT COMPONENTS WITH RESPIRATOR

  1. Components are color coded to correspond with the appropriate respirator bulk head connectors.
  2. Attach straight harness connectors to respirator bulk head connectors.
  3. Assemble phasitron and aerosol generator ( green to green ).
  4. Attach harness connectors to Phasitron/Aerosol generator.
    1. white tubing to white phasitron cap
    2. yellow tubing to aerosol generator port
    3. 90 degree red tubing to Phasitron proximal airway port
    4. green tubing to remote switch port

RESPIRATOR ( IPV ) SETUP

  1. The reduction regulator ( black knob ) sets the drive pressure which is noted on the PSI
    gauge atop the unit. NOTE: Normal operation range ( 25-45 PSI ).
  2. The frequency valve sets the respiratory rate.
    1. low range frequency - <95bpm
    2. twelve o'clock setting- 180-210 bpm
    3. high range frequency- > 225 bpm
  3. Source gases
    1. medical air
    2. oxygen - FIO2 40-55%

ADMINISTERING THERAPY

  1. Select source gas. (Use a 50 PSI gas source, either air or oxygen. Do not hook to
    flowmeter).
  2. Set proper driving pressure utilizing the reduction regulator. Normal operational range
    25-45 PSI.
  3. Give the normal amount of medications but add enough dilutent to total 20cc
  4. Set the frequency control for patient comfort. Normally start at mid to high range
    frequency.
  5. Encourage the patient to actively breathe during the inspiratory phase. By actively breathing the patient will minimize “cheek flapping” and “nasal venting.”
    1. Normal inspiratory phase is 5 to 10 seconds and the unit is activated by the therapist or patient by utilizing the remote switch. On occasion some patients prefer a longer
      inspiratory time. Do not allow the patient to fatigue.
    2. During the expiratory phase, 20 seconds or longer, the patient is encouraged to
      continue breathing through the mouthpiece to continue to receive medications.
  6. When administering IPV directly to a tracheostomy tube, use the entrainment gate
    with the green pressure relief sleeve on it. Also leave the cuff deflated when
    administering IPV directly to a trach tube when the patient is not being mechanically
    ventilated.
  7. When administering IPV to a mechanically ventilated patient use the entrainment gate
    with the green pressure relief sleeve on it.
  8. The nebulizer and phasitron are permanent equipment and must be changed once a day.
    these can be pasteurized. The colored tubing harness does not require daily cleaning
    but should be wiped down with cleaning agent between patients.

NOTE: to improve mobilization of retained secretions scan the entire frequency range to find the proper resonance. If this movement does not mobilize retained secretions, reset the frequency to the easy setting and selectively begin to raise the respirator drive pressure several PSIG and repeat the frequency control movement.

TROUBLESHOOTING / MAINTENANCE

  1. All rubber components should be lubed at least weekly. Use the provided lube tube.
  2. Unit autocycles without depressing the remote control. Check end connectors/o-rings
    on the green harness line. If the problem is not corrected the respirator may be the
    culprit or the cartridge or internal check valve may be leaking. Return for service.
  3. Remote control “sticks”. Disassemble the remote switch and clean the components or
    replace with a new assembly.
  4. Aerosol generator will not mist. Replace the baffle diffractor and cap or replace the
    unit.
  5. Patient manometer does not register. Internal orifice clogged. Return for service. Also
    check the harness filter on the red line.
  6. Leak in reduction regulator. Replace regulator internal components.
  7. Broken harness connectors. Replace with A50041 straight adaptor or A50042 90
    degree adaptor.
  8. Will not nebulize. Check to see that the harness has been assembled properly. The
    yellow line one way valve must point towards the aerosol generator.
  9. Loss of frequency variation. Return unit for recalibration service.

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