Use of respiratory impedance in prehospital care of hypotensive patients associated with hemorrhage and trauma: A case series
ABSTRACT The respiratory pump can be optimized to enhance circulation in patients with hypotension by having patients spontaneously breathe through a low level of inspiratory resistance. This can be achieved with an impedance threshold device (ITD) designed to provide 7 cm H2O resistance during spontaneous inspiration with minimal resistance during expiration. Little is known about the effects of harnessing this physiological concept to increase blood pressure (BP) in the prehospital setting of care for patients with hypotension caused by blood loss or trauma. In this case series, we report on the feasibility, effectiveness, and safety of rapidly deploying the ITD by first responders to treat hypotension secondary to blood loss and trauma in the urban setting by emergency medical services personnel.
Hemodynamic data from hypotensive patients (pretreatment systolic BP [SBP] <100 mm Hg) from 3 U.S. cities where the ITD is deployed were evaluated. The primary end point was maximum change in SBP and diastolic BP (DBP) from before to during ITD use in patients with hypotension secondary to documented blood loss or trauma. Secondary end points were device tolerance, whether the patient felt "better," change in heart rate, O2 saturation, and adverse events.
Of the 255 hypotensive patients treated, there were 26 categorized with blood loss and 13 with trauma. In this 39-patient subgroup, the SBP and DBP (mean ± SD) increased from 79 ± 14 mm Hg and 48 ± 12 mm Hg before ITD placement to 110 ± 17 mm Hg and 66 ± 14 mm Hg after ITD placement (p < 0.001). Breathing through the ITD resulted in no reported adverse events, was well tolerated, and resulted in feeling "better" in more than 85% of the patients.
Use of an ITD by emergency medical services personnel on hypotensive spontaneously breathing patients secondary to blood loss and trauma increased SBP and DBP and was feasible, well tolerated, and not associated with adverse effects (e.g., increased bleeding).
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ABSTRACT: An impedance threshold device (ITD) intended for use in the spontaneously breathing patient has been shown to raise blood pressure in hypotensive patients. This device has not been evaluated in patients with hypotension secondary to trauma. This study focused on changes in key vital signs when the ITD was added to the paramedic treatment protocol for hypotensive patients with prehospital traumatic injury.Journal of Trauma and Acute Care Surgery 09/2014; 77(3 Suppl 2):S140-S145. DOI:10.1097/TA.0000000000000368 · 1.97 Impact Factor
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ABSTRACT: BACKGROUND: Impedance threshold device technology harnesses the patient's normal physiological mechanisms to increase circulation during hypotensive crises. We report the first clinical use of one version of this device on a spontaneously breathing hypotensive pregnant woman. OBJECTIVE: The objective of our study was to report this case to help Emergency Medical Service rescue personnel to noninvasively treat hypotensive but conscious spontaneously breathing patients. CASE REPORT: A 28-year-old woman who was 21 weeks pregnant developed frank syncope at home but recovered spontaneously. When Emergency Medical Service paramedics arrived, her initial blood pressure and heart rate were 115/80 mm Hg and 125 beats/min, respectively. She suddenly complained of feeling anxious and developed profound bradycardia and hypotension, followed by 20 s of asystole. An impedance threshold device (ResQGARD(TM)) with -7 cmH2O resistance to inspiration was rapidly applied using a facemask. After four spontaneous breaths, blood pressure increased from 62/40 mm Hg to 106/66 mm Hg. She was hemodynamically stable thereafter. CONCLUSIONS: In this case report, the multiple physiological effects of inspiration through -7 cmH2O resistance helped this pregnant hypotensive patient to rapidly and noninvasively restore adequate perfusion and reduced the duration of her hypotensive episode. To our knowledge, this is the first report of this technology in a pregnant hypotensive but spontaneously breathing patient.Journal of Emergency Medicine 06/2013; 45(4). DOI:10.1016/j.jemermed.2013.03.036 · 1.18 Impact Factor