An Impedance Threshold Device Increases Blood Pressure in Hypotensive Patients

Smith, Stephen W.; Parquette, Brent; Lindström, David; Metzger, Anja; Kopitzke, Joni; Clinton, Joseph E.

doi:10.1016/j.jemermed.2010.05.013

Cited by 13 publications

(11 citation statements)

References 18 publications

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“…In the first paper, 22 two elements of a study are described. Not all subjects were trauma patients, although they were included and described for the first time.…”

Section: Human Evidencementioning

confidence: 99%

“…2 However, the American Heart Association recommended the use of ITDs in their 2005 guidelines, and the US Federal Drug Administration approved the device for use in patients with low-circulating volume (except those patients with active congestive heart failure, dilated cardiomyopathy, pulmonary hypertension, aortic stenosis, flail chest, chest pain or shortness of breath) in 2003. 3,4 This article reviews the evidence for the use of ITDs in spontaneously breathing hypotensive trauma patients. Due to the differences in pathophysiology and the way negative intra-thoracic pressure is generated between patients in cardiac arrest and those who are spontaneously breathing, data from studies on cardiac arrest have not been included in this analysis.…”

Section: Introductionmentioning

confidence: 99%

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The use of impedance threshold devices in spontaneously breathing, hypotensive trauma patients

Henning

Smith

2014

Trauma

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Impedance threshold devices are a novel therapeutic option to increase blood pressure in the spontaneously breathing, hypotensive, trauma patient. They have multiple potential mechanisms of action. The most important is their ability to induce a more negative intrathoracic pressure during inspiration. They achieve this by the presence of a series of valves.These valves only open once the patient has generated a more negative intrathoracic pressure than is normally required for inspiration to occur. This negative intrathoracic pressure is thought to increase venous return and therefore cardiac output and subsequently blood pressure. This narrative review examines the evidence pertaining to the use of these devices in spontaneously breathing, hypotensive, trauma patients. While the literature supports the ability of these devices to increase systolic blood pressure in both animal and human models of hypotension, and more recently in patients with true pathological hypotension, potential flaws are discussed, and several key questions that have not been addressed by studies to date are highlighted. Notwithstanding these problems, impedance threshold devices may have a role in hypotensive trauma patients, particularly during the pre-hospital phase of care when available resources limit treatment options. Further work is required to prove both their clinical effectiveness and safety.

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“…In the first paper, 22 two elements of a study are described. Not all subjects were trauma patients, although they were included and described for the first time.…”

Section: Human Evidencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The use of impedance threshold devices in spontaneously breathing, hypotensive trauma patients

Henning

Smith

2014

Trauma

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“…5,[8][9][10]19,31,32 The most extensive experience is in the setting of CPR, where the intrathoracic pressure decrease is generated by chest-wall recoil during the CPR decompression phase, when the ITD prevents respiratory gas from entering the thorax except when a positive-pressure breath is delivered. In animals and patients in cardiac arrest and receiving standard CPR, enhancing the negative intrathoracic vacuum during the decompression phase with inspiratory resistance doubles blood flow to the heart and brain, 33 doubles blood pressure in patients 10 and doubles the likelihood of short-term, and in some cases long-term, survival.…”

Section: Clinical Relevance Of the Respiratory Pump Outcomes From CLImentioning

confidence: 99%

“…Studies have shed light on how to easily use the thoracic pump to augment venous blood flow return, lower intracranial pressure, and regulate cardiopulmonary-cerebral blood flow in spontaneously breathing individuals and in patients in cardiac arrest receiving cardiopulmonary resuscitation (CPR). [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Mechanisms Underlying the Hemodynamic Effectiveness of the Respiratory Pump…”

Section: Introductionmentioning

confidence: 99%

Optimizing the Respiratory Pump: Harnessing Inspiratory Resistance to Treat Systemic Hypotension

et al. 2011

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We review the physiology and affects of inspiration through a low level of added resistance for the treatment of hypotension. Recent animal and clinical studies demonstrated that one of the body's natural response mechanisms to hypotension is to harness the respiratory pump to increase circulation. That finding is consistent with observations, in the 1960s, about the effect of lowering intrathoracic pressure on key physiological and hemodynamic variables. We describe studies that focused on the fundamental relationship between the generation of negative intrathoracic pressure during inspiration through a low level of resistance created by an impedance threshold device and the physiologic sequelae of a respiratory pump. A decrease in intrathoracic pressure during inspiration through a fixed resistance resulting in a pressure difference of 7 cm H 2 O has multiple physiological benefits, including: enhanced venous return and cardiac stroke volume, lower intracranial pressure, resetting of the cardiac baroreflex, elevated cerebral blood flow oscillations, increased tissue blood flow/pressure gradient, and maintenance of the integrity of the baroreflexmediated coherence between arterial pressure and sympathetic nerve activity. While breathing has traditionally been thought primarily to provide gas exchange, studies of the mechanisms involved in animals and humans provide the physiological underpinnings for "the other side of breathing": to increase circulation to the heart and brain, especially in the setting of physiological stress. The existing results support the use of the intrathoracic pump to treat clinical conditions associated with hypotension, including orthostatic hypotension, hypotension during and after hemodialysis, hemorrhagic shock, heat stroke, septic shock, and cardiac arrest. Harnessing these fundamental mechanisms that control cardiopulmonary physiology provides new opportunities for respiratory therapists and others who have traditionally focused on ventilation to also help treat serious and often life-threatening circulatory disorders.

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“…14 Recently, this ITD technology has been used for treatment of hypotension in spontaneously breathing patients in several emergency medical services (EMS) systems across the United States. The new approach was first deployed with advanced life support (ALS) providers 15 and, more recently, by first responders who provide basic life support (BLS) and who are unable or unequipped to perform invasive hemodynamic interventions. We report here the results from the first case series of subjects experiencing hypotension secondary to both traumatic and nontraumatic hemorrhage.…”

mentioning

confidence: 99%

Use of respiratory impedance in prehospital care of hypotensive patients associated with hemorrhage and trauma

Convertino

Parquette

Zeihr

et al. 2012

Journal of Trauma and Acute Care Surgery

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An Impedance Threshold Device Increases Blood Pressure in Hypotensive Patients

Cited by 13 publications

References 18 publications

The use of impedance threshold devices in spontaneously breathing, hypotensive trauma patients

The use of impedance threshold devices in spontaneously breathing, hypotensive trauma patients

Optimizing the Respiratory Pump: Harnessing Inspiratory Resistance to Treat Systemic Hypotension

Use of respiratory impedance in prehospital care of hypotensive patients associated with hemorrhage and trauma

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