Official reprint from UpToDate®
www.uptodate.com
©2011 UpToDate®
High-frequency ventilation in adults
Authors
Anthony J Courey, MD
Robert C Hyzy, MD
Section Editor
Polly E Parsons, MD
Deputy Editor
Kevin C Wilson, MD
Last literature review version 18.3:
September 2010 | This topic last updated:
August 2, 2010
INTRODUCTION — High-frequency
ventilation (HFV) is a form of mechanical
ventilation that combines very high
respiratory rates (>60 breaths per minute)
with tidal volumes that are smaller than the
volume of anatomic dead space [1]. The
indications for HFV are limited and its use
should be coordinated by clinicians who have
experience using HFV.
This topic review describes the different types
of HFV, as well as patient selection, efficacy,
and potential harms. Alternative modes of
mechanical ventilation are described
separately. (See "Modes of mechanical
ventilation".)
TYPES OF HFV — There are four basic
types of HFV: high frequency jet ventilation,
high frequency oscillatory ventilation, high
frequency percussive ventilation, and high
frequency positive pressure ventilation (figure
1).
High frequency jet ventilation — High
frequency jet ventilation (HFJV) refers to
HFV delivered using a jet of gas (figure 1). It
is initiated by inserting into the lumen of the
endotracheal tube a small (14 to 16 gauge)
cannula, which is connected to a specialized
ventilator. An initial pressure of
approximately 35 pounds per square inch
(psi) drives the jet of gas from the cannula
with an initial respiratory rate of 100 to 150
breaths per minute and an inspiratory fraction
less than 40 percent (figure 2). The
inspiratory fraction is the inspiratory time
divided by the sum of the inspiratory and
expiratory times. Applied positive endexpiratory pressure (PEEP) can be added if
needed.
An arterial blood gas should be measured
approximately 15 minutes after the initiation
of HFJV:
•
•
•
Appropriate adjustments when the
arterial carbon dioxide tension
(PaCO2) is elevated include:
increasing the driving pressure in 5 psi
increments to a maximum of 50 psi,
increasing the inspiratory fraction in 5
percent increments to a maximum of
40 percent, increasing the frequency
in 10 breaths per minute increments to
a maximum of 250 breaths per minute,
or adding an another mode of
mechanical ventilation (see "Modes of
mechanical ventilation")
Appropriate adjustments when the
PaCO2 is low include: decreasing the
driving pressure in 5 psi decrements,
decreasing the inspiratory fraction in 5
percent decrements to a minimum of
20 percent, or decreasing the
frequency in 10 breaths per minute
decrements to a minimum of 100
breaths per minute
Appropriate adjustments when the
arterial oxygen tension (PaO2) is low
include: adding applied PEEP in 3 to
5 cmH2O increments, increasing the
driving pressure by 5 psi increments
to a maximum of 50 psi, or increasing
the inspiratory fraction in 5 percent
•
increments to a maximum of 40
percent
Appropriate adjustments when the
PaO2 is high include: decreasing the
fraction of inspired oxygen (FiO2) or
decreasing applied PEEP
A respiratory rate of approximately 150
breaths per minute is generally required
during HFJV. Use of ultrahigh frequency jet
ventilation (180 to 400 breaths per minute) in
patients with ARDS has been reported,
although the study had numerous important
limitations [2]. HFJV always requires
sedation and usually requires pharmacologic
paralysis also. (See "Sedative-analgesic
medications in critically ill patients:
Selection, initiation, maintenance, and
withdrawal" and "Use of neuromuscular
blocking medications in critically ill
patients".)
High frequency oscillatory ventilation —
High frequency oscillatory ventilation
(HFOV) uses an oscillatory pump to deliver a
respiratory rate of 3 to 15 Hertz (up to 900
breaths per minute) through the endotracheal
tube (figure 1). This rate is so fast that the
airway pressure merely oscillates around a
constant mean airway pressure. The
respiratory rate is set directly by the clinician.
The mean airway pressure is set by adjusting
the inspiratory flow rate and an expiratory
back pressure valve (similar to applied PEEP)
[3]. Some pumps allow the mean airway
pressure to be set directly.
The constant mean airway pressure maintains
alveolar recruitment, avoids low endexpiratory pressures, and avoids high peak
airway pressures. It also impacts oxygenation.
Specifically, a higher mean airway pressure is
associated with better oxygenation. HFOV
induces a higher mean airway pressure than
most modes of mechanical ventilation.
The tidal volume (also called amplitude) is
small during HFOV, usually less than or
equal to the anatomic dead space. The
amplitude depends on the endotracheal tube
size and respiratory frequency: a smaller
amplitude results when the endotracheal tube
is small or the respiratory frequency is high
[4].
High frequency percussive ventilation —
High frequency percussive ventilation
(HFPV) combines HFV plus time cycled,
pressure-limited controlled mechanical
ventilation (ie, pressure control ventilation,
PCV). It can be conceptualized as HFOV
oscillating around two different pressure
levels, the inspiratory and expiratory airway
pressures [5]. HFPV improves oxygenation,
improves ventilation, and lowers airway
pressures (peak, mean, and end-expiratory),
compared to other modes of mechanical
ventilation. (See "Modes of mechanical
ventilation", section on 'Pressure-limited
ventilation'.)
HFPV is possible because of a device called a
phasitron. The phasitron is an inspiratory and
expiratory valve located at the end of the
endotracheal tube. High-pressure gas drives
the phasitron to deliver small tidal volumes at
a high frequency (200 to 900 beats per min),
superimposed on the inspiratory and
expiratory airway pressures of PCV. The
PCV is typically delivered at a respiratory
rate of 10 to 15 breaths per min.
HFPV does not require pharmacologic
paralysis. In addition, it clears secretions
more effectively than other types of HFV [5].
High frequency positive pressure
ventilation — High frequency positive
pressure ventilation (HFPPV) is rarely used
anymore, having been displaced by the types
of HFV discussed above. HFPPV is delivered
through the endotracheal tube using a
conventional ventilator whose frequency is
set near its upper limits (figure 1).
PATIENT SELECTION — There are no
universally accepted indications for HFV. Its
use has been described in a variety of clinical
situations, including ALI/ARDS,
bronchopleural fistula, inhalational injury,
blunt trauma induced ARDS, and head
injuries complicated by high intracranial
pressure [5-8].
•
•
ALI/ARDS — The theoretical benefit
of using HFV in patients with
ALI/ARDS relates to the small tidal
volumes. A strategy of low tidal
volume ventilation has been proven in
randomized trials to improve
mortality, possibly due to decreased
alveolar distension and ventilatorassociated lung injury. Although the
trials did not use HFV, many
clinicians suspect that HFV confers a
similar benefit. Until this is proven,
HFV should not be considered routine
care for patients with ALI/ARDS.
HFV is used by some clinicians when
there is persistent hypoxemia during
the first three days of mechanical
ventilation despite maximal
conventional therapy, although the
data to support this are limited [9,10].
(See "Mechanical ventilation in acute
respiratory distress syndrome", section
on 'Low tidal volume ventilation' and
"Ventilator-associated lung injury".)
Bronchopleural fistula — HFJV is
approved by the United States Food
and Drug Administration for
ventilating patients in whom a large
and persistent bronchopleural fistula
exists. However, the likelihood that
HFJV will allow the bronchopleural
fistula to close is unpredictable [6,7].
While HFJV may promote fistula
closure by limiting alveolar
distension, this may be outweighed in
some patients by increased plateau
airway pressure (alveolar pressure),
decreased oxygenation, or worse
hypercapnia [7]. (See "Management
of bronchopleural fistula in patients on
mechanical ventilation".)
HFV should be avoided in patients with
obstructive lung disease. The high respiratory
rate used for HFV shortens the expiratory
time, which can cause auto-PEEP and related
sequelae. (See "Positive end-expiratory
pressure (PEEP)", section on 'Auto (intrinsic)
PEEP'.)
EFFICACY — This section describes the
clinical evidence related to the different types
of HFV. Generally speaking, there is
evidence that HFOV and HFPV improve
oxygenation, although neither has been
shown to improve clinical outcomes (eg,
mortality, duration of mechanical ventilation,
or length of ICU stay).
HF jet ventilation — There is little moderate
or high quality data evaluating the efficacy of
HFJV in adults. One trial randomly assigned
a heterogeneous group of 309 patients with
acute respiratory failure to receive HFJV or
volume-limited mechanical ventilation [11].
There was no significant difference in
mortality or the duration of ICU stay. (See
"Modes of mechanical ventilation", section
on 'Volume-limited ventilation'.)
In another trial, seven patients who were
already receiving a traditional mode of
mechanical ventilation for respiratory failure
complicated by a bronchopleural fistula were
randomly assigned to either switch to HFJV
or continue their mode of ventilation [7].
There was no significant difference in the size
of the chest tube leak (a measure of the
bronchopleural fistula), but the HFJV group
developed worse oxygenation and
hypercapnia after switching to the HFJV.
HF oscillatory ventilation — Most studies of
HFOV have been performed in adults with
ALI/ARDS [12-15]. In the largest multicenter
trial, 148 patients with ALI/ARDS were
randomly assigned to undergo mechanical
ventilation using HFOV or pressure control
ventilation (PCV) [12]. The PCV settings
targeted a tidal volume of 6 to 10 ml/kg of
actual body weight. The HFOV group had a
lower mortality rate that was not statistically
significant (37 versus 52 percent). The same
group also had a significantly higher mean
airway pressure and PaO2/FiO2 ratio,
although these differences did not persist
beyond 24 hours.
A meta-analysis of six randomized trials (365
patients), including the trial just described,
found that adults with ALI/ARDS who
received HFOV had significantly lower
hospital mortality or 30-day mortality than
those who received conventional mechanical
ventilation alone (39 versus 49 percent, RR
0.77, 95% CI 0.61-0.98) [15]. A limitation of
this meta-analysis was that some of the trials
that were included did not use low tidal
volume ventilation in their control groups,
which could bias the results in favor of
HFOV. When trials that allowed tidal
volumes ≥8 mL/kg were excluded and the
meta-analysis repeated, there was a trend
toward lower mortality among patients who
received HFOV (RR 0.67, 95% CI 0.44-1.03).
These results indicate that the repeat metaanalysis was too small to exclude or confirm
a clinically important effect and additional
trials are necessary to compare the effects of
HFOV and low tidal volume ventilation on
mortality. (See "Mechanical ventilation in
acute respiratory distress syndrome", section
on 'Low tidal volume ventilation'.)
The effects of HFOV combined with another
intervention have also been evaluated.
Generally speaking, HFOV improves
oxygenation when combined with inhaled
nitric oxide or recruitment maneuvers,
[16,17]. It may also prevent worsening of
hypoxemia when a patient returns to the
supine position following prone ventilation
[18]. None of these combinations have been
shown to improve important clinical
outcomes and all of the studies had significant
methodologic limitations.
It was hypothesized that the duration of
mechanical ventilation using a conventional
mode prior to HFOV correlates with mortality
[16]. However, a meta-analysis of nine
studies (two randomized trials and seven
observational studies) found no such
relationship, even after confounding variables
were considered [19]. Only the oxygenation
index was independently associated with
mortality. (See "Oxygenation and
mechanisms of hypoxemia", section on
'Oxygenation index'.)
HFOV at a respiratory rate greater than 6 Hz
may be required because the usual respiratory
rate of 3 to 6 Hz results in airway pressures
that are potentially not lung protective. The
feasibility of this approach was demonstrated
by a single center, prospective cohort study of
30 patients with ARDS who were receiving
HFOV after failing conventional lung
protective ventilation [20]. Among the
patients whose respiratory rates exceeded 6
Hz (range 6 to 15 Hz), most were able to meet
their oxygenation (PaO2 55 to 80 mmHg) and
ventilatory goals (pH 7.25 to 7.35). The effect
of this strategy on mortality is not known; as
a result, we cannot recommend this approach
as a rescue modality. (See "Mechanical
ventilation in acute respiratory distress
syndrome", section on 'Low tidal volume
ventilation'.)
HF percussive ventilation — HFPV improves
both oxygenation and ventilation without
hemodynamic instability or clinically evident
pulmonary barotrauma [5,21,22]. It may also
decrease intracranial pressure in patients with
head injuries [5].
•
•
A trial randomly assigned 35 patients
with inhalational injury to undergo
HFPV or volume-limited mechanical
ventilation [21]. The HFPV group had
significant improvement in the
PaO2/FiO2 ratio of the initial 72
hours, compared to the volumelimited ventilation group.
An uncontrolled trial of 54 patients
with ALI/ARDS demonstrated
improved oxygenation, decreased
physiologic shunting, and decreased
peak airway pressures after changing
the mode of ventilation to HFPV [22].
HARMS — HFV is not risk free. The high
respiratory rate shortens the expiratory time,
potentially causing auto-PEEP and dynamic
hyperinflation. The plateau airway pressure
(alveolar pressure) and mean airway pressure
are likely to increase if auto-PEEP and
dynamic hyperinflation develop, elevating the
risk of pulmonary barotrauma and
hemodynamic instability. This occurs despite
a lower peak airway pressure conferred by the
smaller tidal volumes. In one trial, the risk of
pulmonary barotrauma or hemodynamic
instability was the same for patients receiving
HFV compared to those receiving an
alternative mode of mechanical ventilation
[2]. (See "Pulmonary barotrauma during
mechanical ventilation" and "Physiologic and
pathophysiologic consequences of mechanical
ventilation", section on 'Hemodynamics'.)
There are also complications unique to type
of HFV. As an example, HFJV is associated
with necrotizing tracheobronchitis,
endotracheal tube mucus inspissation, and
variability of cardiac output [23]. Proper gas
humidification reduces the likelihood of
necrotizing tracheobronchitis or endotracheal
tube mucus inspissation.
SUMMARY AND RECOMMENDATIONS
•
•
•
•
•
High-frequency ventilation (HFV)
combines a very high respiratory rate
with tidal volumes that are smaller
than the volume of anatomic dead
space. (See 'Introduction' above.)
There are four types of HFV: highfrequency jet ventilation (HFJV),
high-frequency oscillatory ventilation
(HFOV), high-frequency percussive
ventilation (HFPV), and highfrequency positive pressure ventilation
(HFPPV). (See 'Types of
HFV' above.)
There are no universally accepted
indications for HFV. Its use has also
been described in a variety of clinical
situations. HFV should be avoided in
patients with obstructive lung disease.
(See 'Patient selection' above.)
There is evidence that HFOV and
HFPV improve oxygenation, although
neither has been conclusively shown
to improve clinical outcomes (eg,
mortality, duration of mechanical
ventilation, or length of ICU stay).
(See 'Efficacy' above.)
HFV is not risk free. Potential harms
include intrinsic positive endexpiratory pressure (auto-PEEP),
dynamic hyperinflation, and related
sequelae (eg, pulmonary barotrauma,
hemodynamic instability). In addition,
there are specific risks associated with
each type of HFV. (See
'Harms' above.)
Use of UpToDate is subject to the
Subscription and License Agreement.
REFERENCES
1. Standiford, TJ, Morganroth, ML.
High-frequency ventilation. Chest
1989; 96:1380.
2. Gluck, E, Heard, S, Patel, C, et al. Use
of ultrahigh frequency ventilation in
patients with ARDS. A preliminary
report. Chest 1993; 103:1413.
3. Fessler, HE, Derdak, S, Ferguson,
ND, et al. A protocol for highfrequency oscillatory ventilation in
adults: results from a roundtable
discussion. Crit Care Med 2007;
35:1649.
4. Hager, DN, Fessler, HE, Kaczka, DW,
et al. Tidal volume delivery during
high-frequency oscillatory ventilation
in adults with acute respiratory
distress syndrome. Crit Care Med
2007; 35:1522.
5. Salim, A, Martin, M. High-frequency
percussive ventilation. Crit Care Med
2005; 33:S241.
6. Carlon, GC, Ray C, Jr, Klain, M,
McCormack, PM. High-frequency
positive-pressure ventilation in
management of a patient with
bronchopleural fistula. Anesthesiology
1980; 52:160.
7. Bishop, MJ, Benson, MS, Sato, P,
Pierson, DJ. Comparison of highfrequency jet ventilation with
conventional mechanical ventilation
for bronchopleural fistula. Anesth
Analg 1987; 66:833.
8. Eastman, A, Holland, D, Higgins, J, et
al. High-frequency percussive
ventilation improves oxygenation in
trauma patients with acute respiratory
distress syndrome: a retrospective
review. Am J Surg 2006; 192:191.
9. Mehta, S, Granton, J, MacDonald, RJ,
et al. High-frequency oscillatory
ventilation in adults: the Toronto
experience. Chest 2004; 126:518.
10. David, M, Weiler, N, Heinrichs, W, et
al. High-frequency oscillatory
ventilation in adult acute respiratory
distress syndrome. Intensive Care
Med 2003; 29:1656.
11. Carlon, GC, Howland, WS, Ray, C, et
al. High-frequency jet ventilation. A
12.
13.
14.
15.
16.
17.
18.
prospective randomized evaluation.
Chest 1983; 84:551.
Derdak, S, Mehta, S, Stewart, TE, et
al. High-frequency oscillatory
ventilation for acute respiratory
distress syndrome in adults: a
randomized, controlled trial. Am J
Respir Crit Care Med 2002; 166:801.
Bollen, CW, van Well, GT, Sherry, T,
et al. High frequency oscillatory
ventilation compared with
conventional mechanical ventilation in
adult respiratory distress syndrome: a
randomized controlled trial
[ISRCTN24242669]. Crit Care 2005;
9:R430.
Mentzelopoulos, SD, Roussos, C,
Koutsoukou, A, et al. Acute effects of
combined high-frequency oscillation
and tracheal gas insufflation in severe
acute respiratory distress syndrome.
Crit Care Med 2007; 35:1500.
Sud, S, Sud, M, Friedrich, JO, et al.
High frequency oscillation in patients
with acute lung injury and acute
respiratory distress syndrome
(ARDS): systematic review and metaanalysis. BMJ 2010; 340:c2327.
Mehta, S, MacDonald, R, Hallett, DC,
et al. Acute oxygenation response to
inhaled nitric oxide when combined
with high-frequency oscillatory
ventilation in adults with acute
respiratory distress syndrome. Crit
Care Med 2003; 31:383.
Ferguson, ND, Chiche, JD, Kacmarek,
RM, et al. Combining high-frequency
oscillatory ventilation and recruitment
maneuvers in adults with early acute
respiratory distress syndrome: the
Treatment with Oscillation and an
Open Lung Strategy (TOOLS) Trial
pilot study. Crit Care Med 2005;
33:479.
Demory, D, Michelet, P, Arnal, JM, et
al. High-frequency oscillatory
19.
20.
21.
22.
23.
ventilation following prone
positioning prevents a further
impairment in oxygenation. Crit Care
Med 2007; 35:106.
Bollen, CW, Uiterwaal, CS, van
Vught, AJ. Systematic review of
determinants of mortality in high
frequency oscillatory ventilation in
acute respiratory distress syndrome.
Crit Care 2006; 10:R34.
Fessler, HE, Hager, DN, Brower, RG.
Feasibility of very high-frequency
ventilation in adults with acute
respiratory distress syndrome. Crit
Care Med 2008; 36:1043.
Reper, P, Wibaux, O, Van Laeke, P, et
al. High frequency percussive
ventilation and conventional
ventilation after smoke inhalation: a
randomised study. Burns 2002;
28:503.
Hurst, JM, Branson, RD, DeHaven,
CB. The role of high-frequency
ventilation in post-traumatic
respiratory insufficiency. J Trauma
1987; 27:236.
Angus, DC, Lidsky, NM,
Dotterweich, LM, Pinsky, MR. The
influence of high-frequency jet
ventilation with varying cardiac-cycle
specific synchronization on cardiac
output in ARDS. Chest 1997;
112:1600.
GRAPHICS
Modes of high frequency ventilation
Modes of high frequency ventilation. With high frequency positive pressure ventilation (top),
high-pressure conditioned gas (a) is delivered during inhalation and flows predominantly through
an endotracheal tube (b) to the patient with partial escape to the atmosphere. During exhalation,
the gas exits through an optional one-way valve (c). With high frequency jet ventilation (middle),
conditioned high-pressure gas enters from a cannula (a) at a selected level along the endotracheal
tube or trachea (c). This gas entrains additional conditioned gas (b) by the Venturi effect. During
exhalation the gas exits passively through an optional one-way valve (d). With high frequency
oscillation (bottom), the piston or diaphragm (a) oscillates while fresh conditioned gas (bias
flow) enters (b) and exhaust gas exits (c) at a balanced constant rate. The bias flow ports can be
positioned anywhere along the path from the external tip of the endotracheal tube to within the
trachea itself.
Initial jet ventilator settings
* If the patient was hypoxic with controlled mechanical ventilation, driving pressure should be
adjusted as necessary to achieve a mean airway pressure equal to that present during controlled
mechanical ventilation. If minute ventilation under those conditions is not at least equal to that
present during controlled mechanical ventilation, driving pressure should be further increased
until this condition is met before obtaining arterial blood gas levels. If the patient was
hypercapnic with controlled mechanical ventilation, driving pressure should be adjusted as
necessary to achieve a minute ventilation two times that present during controlled mechanical
ventilation. If mean airway pressure exceeds 110 percent of that present during controlled
mechanical ventilation before obtaining that minute ventilation, arterial blood gas levels should
be obtained at that point before further increasing driving pressure. In individual patients,
changes in rate may have opposite effects on PaCO2.
• Careful monitoring of peak, mean, and end-expiratory airway pressure as well as minute
ventilation and oximetry should be performed when any change is made in ventilatory
parameters. Only experienced personnel should use high-frequency jet ventilation. Redrawn
from: Standiford, TJ, Morganroth, ML, Chest 1989; 96:1383.