American Association for Respiratory Care’s
, VA 22042
In This Issue…
Notes from the Editors Jenni L. Raake, RRT, and Natalie Napolitano, MPH,
High Frequency Percussive Ventilation in the Pediatric
Rita Giordano, RRT-NPS
Case Study 1: Application of High Frequency Percussive
Ventilation in a Patient with Radiation Pneumonitis as a
Maureen Ginda, BS, RRT-NPS
Lung Protective Strategy while Awaiting Lung
Case Study 2: Application of High Frequency Percussive
Ventilation with Asthma
Cheryl Dominick, BS, RRT-NPS
Notes from the Editors
Jenni L. Raake, RRT, and Natalie Napolitano, MPH, RRT-NPS
This issue of the Bulletin is dedicated to a closer look at high frequency percussive ventilation
(HFPV), provided for us by three of our members from the Children’s Hospital of Philadelphia.
Rita Giordano kicks things off with an overview of HFPV, and Maureen Ginda and Cheryl
Dominick follow with interesting case studies on patients who were treated with HFPV in their
High Frequency Percussive Ventilation in the
Rita Giordano, RRT-NPS, Children’s Hospital of Philadelphia, Philadelphia, PA
What do you think of when you hear the words “high frequency”? To many of us who work in
respiratory care, high frequency means a type of mechanical ventilation that employs very
high respiratory rates (>150 breaths per minute) and small tidal volumes. The two types of
high frequency ventilators (HFV) most commonly utilized are the jet ventilator (HFJV, rate
100–600/minute) and the oscillatory ventilator (HFOV, rate 300–3000/minute). However,
there is a third type, and it is capable of providing high frequency ventilation to preterm
infants through adults.
Developed by Forrest Bird, MD, PhD, in the early 1980s, high frequency percussive ventilation
(HFPV) is provided by a pneumatically powered, time-cycled, pressure-regulated ventilator
that also delivers inspiratory and expiratory oscillations.1 It was approved for patient use by
the Food and Drug Administration in 1993. The HFPV Volume Diffusive Respirator (VDR-4®) is
engineered to provide oxygenation and carbon dioxide elimination using lung-protective
The phasitron piston mechanism, which acts as the inspiratory and expiratory valve, is driven
by a high-pressure gas supply at a rate of 200–900 beats per minute.1 The VDR provides
percussive sub-tidal volumes at high rates that are stacked in a stepwise fashion and are
superimposed onto conventional convective pressure control type breaths.1 The lung volumes
are progressively increased during inspiration with sub-tidal volume delivery until an
oscillatory plateau is reached and maintained at end-inspiration. The lung emptying occurs
during an oscillating passive exhalation to a desired end-expiratory pressure.1
The intrapulmonary percussions at high frequencies that are inherent in HFPV provide for
mobilization of secretions and more uniformed intrapulmonary gas exchange with improved
distal ventilation.2 Each percussive breath is responsive to changes in compliance of the lung.
The I:E ratio is usually maintained at 1:1, resulting in oscillatory plateau. With HFPV, the
convective positive-pressure breaths are controlled breaths, with no assisted breaths available
to the patient. Spontaneous breathing can be accomplished through a demand valve system
and is available throughout the breathing cycle.
The main differences between the high frequency machines are: mean airway pressures can
fluctuate with the HFPV and HFJV, whereas with the HFOV, mean airway pressures are held
constant under optimal conditions. Exhalation using the HFPV and HFJV is passive while with
the HFOV it is active. Weaning and liberation from the VDR-4 ventilator can be accomplished
through the continuous demand flow system.
Although documented evidence is limited, some have found that HFPV should be considered as
an option for patients with smoke inhalation injury and ARDS. Cioffe et al. published a case
series of 54 adult burn patients with inhalation injury who were prophylactically placed on the
VDR upon admission.3 They found a significantly lower rate of pneumonia and mortality in the
group treated with HFPV.
Reper et al. did a randomized trial of 35 adult patients with inhalation injury who were on
HFPV and conventional ventilation (CV), comparing gas exchange, lung injury, and
hemodynamics.4 The HFPV group showed a significant improvement in P/F ratio in the first 72
hours of use, with no difference in the hemodynamic status or clinical evidence of barotraumas
between the two groups.
Fifty-four adult trauma patients with post-injury ARDS and refractory hypoxemia who were
studied by Hurst et al. showed improvement in oxygenation with HFPV, with a decrease in
peak airway pressures without significant barotrauma.5 Hurst et al. also took a look at 100
adults with acute respiratory failure who were randomized to CV or HFPV.6 The defined
endpoints were P/F ratio and intrapulmonary shunt fraction. No difference was seen between
the time it took to reach these endpoints. However, the investigators did note significantly
lower airway pressures for the ARDS patients on HFPV throughout the study period.
Velmahos et al. reported a case series of 32 adult medical and surgical ARDS patients with
consistent case exchange failure on CV that was transitioned to HFPV.7 After transition to
HFPV, P/F ratio and PIP improved within one hour, with sustained improvement throughout
the study period.
Recent studies in the pediatric population have been in the burn and inhalation injury
population. Mlcak et al. performed a randomized, prospective trial of 43 children with
inhalation injury, randomizing them to CV or HFPV.8 The HFPV group maintained adequate
ventilation with lower PIPs, with a trend towards lower mortality and incidence of ventilator
Carmen et al. also evaluated smoke injury patients, taking a prospective look at 64 patients
with ARF who were randomized to CV or HFPV.9 The CV group utilized low tidal volume
ventilation with 6-8 cc/kg. The results showed significant improvement in oxygenation and PIP
in the HFPV group.
At the Children’s Hospital of Philadelphia, we have utilized the VDR-4 on patients with
burn/smoke injury, ARDS with secretion clearance issues, and bronchiolitis. We have also used
it as a lung protection and recruitment strategy. With the VDR-4 HFPV we have been
successful in improving ventilation and oxygenation, and providing lung recruitment and
secretion removal, while maintaining patients at a lower airway pressure compared to
1. Salim A, Martin M. High-frequency percussive ventilation. Crit Care Med
2. Freitag L, Long WM, Kim CS, et al. Removal of excessive bronchial secretions by
asymmetric high-frequency oscillations. J Appl Physiol 1989;67:614-619.
3. Cioffi WG, Rue LW, Graves TA, et al. Prophylactic use of high-frequency percussive
ventilation in patients with inhalation injury. Ann Surg 1991;213:575-582.
4. Reper P, Wibaux O, Van Laeke D, et al. High frequency percussive ventilation and
conventional ventilation after smoke inhalation: A randomized study. Burns
5. Hurst JM, Branson RD, DeHaven CB. The role of high-frequency ventilation in posttraumatic
respiratory insufficiency. J Trauma 1987;27:236-242.
6. Hurst JM, Branson RD, Davis L, et al. Comparison of conventional mechanical
ventilation and high frequency ventilation. Ann Surg 1990;211:486-491.
7. Velmahos GC, Chan LS, Tatevossian R, et al. High-frequency percussive ventilation
improves oxygenation in patients with ARDS. Chest 1999;116:440-446.
8. Mlcak RP, Suman OE, Sanford AP, et al. Comparison of high frequency percussive
ventilation in pediatric patients with inhalation injury. J Burns Surg Wound Care (serial
9. Carmen B, Cahill T, Warden G, et al. A prospective, randomized comparison of volume
diffusive respirator vs conventional ventilation for ventilation of burned children. J
Burn Care Rehabil 2002;23:444-448.
Case Study 1: Application of High Frequency
Percussive Ventilation in a Patient with
Radiation Pneumonitis as a Lung Protective
Strategy while Awaiting Lung Transplant
Maureen Ginda, BS, RRT-NPS, Children’s Hospital of Philadelphia, Respiratory Care
Department, Philadelphia, PA
Introduction: The case describes the use of HFPV as a lung protective strategy to treat and
prevent additional air leak syndrome.
Case: A six-year-old patient with neuroblastoma was diagnosed at 20 months of age and
underwent a course of treatment that included resection of the tumor, chemotherapy,
radiation, and stem cell transplant. At five years of age the child was found to have radiation
pneumonitis and shortly thereafter was listed for lung transplantation. The patient presented
to the emergency department with a right sided pneumothorax for which a chest tube was
placed. Hours later the child was admitted to the general care area on high flow nasal cannula
for six weeks.
Respiratory failure continued despite maximal medical therapies, including noninvasive bi-level
ventilation, antibiotics, high dose steroids, and bronchodilators. The progression of the disease
process led to transfer to the ICU, where inotropic infusions were started. Due to poor carbon
dioxide clearance, the patient was subsequently intubated and placed on HFPV via the VDR-4
MODE PIP/PEEP RATE Mean airway
ph PaCO2 PaO2
SIMV PC 50/8 35 24 7.0-7.16 100-130 >100 on 50%
HFPV* 42/7 20/550 23 7.3-7.4 70-80 >100 on 40%
*weaned off epinephrine and dopamine infusions within 24 hours of HFPV starting
After five days of HFPV the patient’s pulmonary status improved and the ventilation strategy
was transitioned to pressure control SIMV with the intent of beginning a pulmonary
rehabilitation program in preparation for transplantation. Within 36 hours bilateral
pneumothoraces and pneumomediastium developed. The patient was again treated with
bilateral chest tubes and placed back on HFPV.
MODE PIP/PEEP RATE Mean airway
pH PaCO2 PaO2
SIMV PC 52/8 60 25 7.4 80’s 90 on 50%
HFPV 35/7 25/500 18 7.4 80’s 90’s on 50%
Within 24 hours all air leaks were resolved. The patient remained on these settings for 18
days, with no further air leaks.
Due to an anticipated long wait for lungs, along with the patient’s inability to participate in
rehabilitation and worsening multisystem organ failure, the patient was deactivated from the
active transplant list. One day later support was withdrawn at the family’s request.
Discussion: Although this case did not have a positive outcome, the therapeutic use of the
VDR-4 HFPV accomplished our goals of maintaining acceptable pH while treating and
preventing additional barotrauma.
BILATERAL AIR LEAK ON SIMV/PC
AFTER 36 HOURS OF HFPV
Case Study 2: Application of High Frequency
Percussive Ventilation with Asthma
Cheryl Dominick, BS, RRT-NPS, Children’s Hospital of Philadelphia, Respiratory Care
Department, Philadelphia, PA
Introduction: The case describes the application of HFPV for lung recruitment, secretion
mobilization, and ventilation in a patient with severe asthma.
Case: A seven-year-old male presented to an outside hospital limp and cyanotic with initial
SpO2 of 80%. He was stabilized on ventilator settings and transferred to Children’s Hospital of
Philadelphia. On arrival to the PICU, he was placed on SIMV with a RR of 24, tidal volume of
200, Peep of 6, and pressure support of 10 with 40% FiO2. He was started on Q1H
bronchodilators and epinephrine for hypotension, and was paralyzed in order to control
The patient was weaned from vent support, transitioned to Q4H bronchodilators, and
extubated to a nasal cannula on hospital day three. The patient had been extubated for 48
hours when he began having acute and severe desaturations to the high 60s. Due to his
hypoxemia, he was reintubated. Despite conventional ventilation and prone positioning, he
continued to be hypoxemic with saturations in the 70s to low 80s. Nitric oxide was started
with no improvement.
On chest x-ray his ETT was in good position, his right lung was hyper-inflated, and he had
complete lung collapse on the left with shift of the mediastinal structures. Bronchoscopy by
ENT demonstrated copious secretions in the branches of the left bronchi. However, no mucus
plug was noted. Some secretions, but not all, were able to be removed via bronchoscopy.
Saturations increased to 90% with aggressive hand-ventilation.
Immediately following the bronchoscopy the decision was made to place the patient on HFPV.
Over a period of three hours we saw significant improvement in his saturations and were able
to wean his oxygen supplementation from 100% to 30%; he was off nitric oxide within eight
hours. The patient remained on HFPV for two days and was successfully extubated to a nasal
cannula the next day (hospital day seven).
VDR settings were as follows:
FIO2/NO Conv Rate Perc Rate PIP Peep MAP
Initial 100/20 20 600 35 6 20
1 hour 70/20 15 600 30 6
3 hours 30/10 15 650 20 6 12
Discussion: Many strategies are used for secretion mobilization in patients with respiratory
failure. HFPV combines the benefits of high frequency ventilation and conventional bulk flow
gas exchange, resulting in effective secretion mobilization. We report the successful use of
HFPV for secretion mobilization in severe asthma.
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