An introduction to
Intrathoracic Pressure Regulation Therapy
49-2057-000, 01
What is Intrathoracic Pressure Regulation?
Intrathoracic Pressure
Regulation (IPR) is a therapy
that enhances negative
pressure in the chest and has
been shown in studies to
effectively improve circulation
of blood to the brain and other
vital organs.1
Pressure and Natural Physiology
Intrathoracic Pressure
The body continually
regulates the circulation of
blood by using positive and
negative pressures inside
the thoracic cavity to
maintain equilibrium.
Positive vs. Negative Pressure
The thoracic cavity is like a bellows…
Positive Pressure
Negative Pressure

PUSHES air away

Creates a vacuum

Inhibits blood return

PULLS fluid and air in

Principle behind CPAP therapy

Principle behind IPR therapy
Normal Physiology
When you exhale (exhalation),
you create a slight positive
pressure, which…
 Forces air out
 Inhibits blood return to the
heart
 Increases intracranial
pressure (ICP)
Conversely when you inhale
(inspiration), you create a slight
negative pressure, which…
 Pulls air into lungs
 Returns blood to the chest
 Lowers ICP
Effect of Intrathoracic Pressure on Blood Flow
Respiration and
circulation are closely
linked. Dating back to
1967, we have known
there is an inverse
relationship between
intrathoracic pressure
and blood flow.
Intrathoracic Pressure (cmH2O)
As intrathoracic
pressure decreases...
blood flow increases.
Blood Flow, Abdominal Vena Cava (l/min-1)
Moreno et al. Respiratory regulation of splanchnic and systemic venous return. Am J Physiol 1967;213:455-465.
Intrathoracic Pressure and ICP Linked
Animal Model with
40% Bleed - No Intervention
Pressures with No Intervention
5
Intrathoracic
Pressure
-5 cmH2O
Intracranial
Pressure
-15
5
0 mmHg
-10
75
Aortic
Pressure
55 mmHg
35
Cerebral
Perfusion
Pressure
75
55 mmHg
35
2 Seconds per Division
Convertino et al. Resp Care 2011;56:846-857.
Compensation and Decline
Normal Physiology - Compensation
The body regulates pressures as
part of its normal compensatory
response.
Under stress, such as when
exercising, one breathes harder,
faster, deeper; this…
•
Enhances negative
pressure in the thoracic
cavity
•
Lowers intracranial
pressure (ICP) to improve
blood flow to the brain
Body in Trouble
However, sometimes a body is
unable to adequately
compensate.
Example: Shock
1.
Heart rate increases in an effort
to maintain sufficient blood flow
2.
Intrathoracic pressure is
modulated in an effort to increase
perfusion
3.
Eventually, body is unable to
adequately compensate and
blood pressure drops
Result: Insufficient perfusion to
protect the brain and other vital
organs.
Intrathoracic Pressure Regulation (IPR)
Positive Pressure
Results:
Continuous positive airway pressure (CPAP)
and positive pressure ventilation (PPV)
are common and well accepted therapies
for pulmonary edema.
1.
Drives fluid out of the lungs
2.
Decreases preload
3.
Decreases cardiac output
4.
Decreases blood pressure
IPR = Negative Pressure
IPR leverages negative intrathoracic pressure to
enhance perfusion; studies1 have shown that it...
Enhances negative intrathoracic pressure2
(i.e. increases the vacuum in the chest), which...
① Draws more blood back to the heart3,7
(i.e. increases preload), which leads to increased
cardiac output and blood pressure
and
① Decreases intracranial pressure (ICP)4,5,6
which makes it easier to get blood into and out of
the brain (i.e. increases cerebral perfusion)
Intrathoracic Pressure Regulation (IPR)
Normal Breathing
(Decreased cardiac output)
(Increased cardiac output)
IPR Therapy
Enhances Negative Pressure
Impact of IPR
ResQGARD ITD
ResQPOD ITD
IPR Therapy is simply using the “other
side of pressure,” enhancing negative
pressure to improve perfusion.
Studies1 show that IPR Therapy:
 Enhances negative intrathoracic
pressure2
 Increases preload3
 Increases cardiac output3
 Increases blood pressure7
 Lowers ICP4,5
 Results in more forward cerebral blood
flow, better perfusion of the brain.6
Intrathoracic Pressure Regulation Therapy
helping the body help itself
Intrathoracic Pressure
Impedance Threshold Devices (ITDs) Deliver IPR
Studies Show1
ResQPOD ITD
ResQGARD ITD
How it Works
Enhances circulation in
patients undergoing CPR
during cardiac arrest
(profound shock)
Prevents the influx of air
during chest wall recoil to
enhance negative
intrathoracic pressure
Enhances circulation in
spontaneously breathing
patients with low blood
pressure (shock)
Creates a slight amount of
therapeutic resistance
during inhalation to
enhance negative
intrathoracic pressure
The Evidence
Impact of IPR on Pressures
Animal Model with 40% Bleed
No IPR
With IPR
5
Intrathoracic
Pressure
-5 cm H2O
Intracranial
Pressure
-15
5
0 mmHg
-10
75
Aortic
Pressure
55 mmHg
35
Cerebral
Perfusion
Pressure
75
55 mmHg
35
2 Seconds per Division
Convertino et al. Resp Care 2011;56:846-857.
Cerebral Blood Flow
ON / OFF Effect of IPR
Mean CBF Velocity (cm/sec)
80
70
60
50
40
IPR On
IPR Off
30
0
100
200
300
400
Time (secs)
Cooke et al. Human autonomic and cerebrovascular responses to inspiratory impedance. J Trauma 2006;60:1275-1283.
For More Information
www.AdvancedCirculatory.com
info@AdvancedCirculatory.com
1-877-737-7763
References
1. The generally cleared indication for the ResQPOD and ResQGARD ITDs available for sale in the
United States is for a temporary increase in blood circulation during emergency care, hospital, clinical,
and home use. Research is ongoing in the United States (US) to evaluate the longer-term benefits of
the ResQPOD and ResQGARD for other specific indications. The studies listed here are not intended
to imply specific outcomes-based claims not yet cleared by the US FDA.
2. Lurie KG, Zielinski T, McNite S, Aufderheid T, Voelckel W. Use of an inspiratory impedance valve
improves neurologically intact survival in a porcine model of ventricular fibrillation. Circulation 2002;
105(1):124-129.
3. Lurie, KG, Voelckel WG, Zielinski T, et al. Improving standard cardiolpulmonary resuscitation with an
inspiratory impedance threshold valve in a porcine model of cardiac arrest. Anesth Analg 2001;93:64955.
4. Aufderheide TP, Alexander C, Lick C, et al. from laboratory science to 6 emergency medical services
systems: new understanding of the physiology of cardiopulmonary resuscitation increases survival rates
after cardiac arrest. Crit Care Med 2008;36(11):S397-S404.
5. Alexander C, Yannopoulos D, Aufderheide T, et al. Dual mechanism of blood flow augmentation to the
brain using an impedance threshold device in a pediatric model of cardiac arrest. Circulation 2007;
116(16):II-433.
6. Lurie KG, Mulligan KA, McNite S, Detloff B, Lindstrom P, Lindner KH. Optimizing standard
cardiopulmonary resuscitation with an inspiratory impedance threshold valve. Chest 1998;113(4):10841090.
7. Pirrallo RG, Aufderheide TP, Provo TA, Lurie KG. Effect of an inspiratory impedance threshold device
on hemodynamics during conventional manual cardiopulmonary resuscitation. Resuscitation
2005;66:13-20.