Abstract 2832: An Impedance Threshold Device Applied by Prehospital Emergency Responders Increases Blood Pressure in Spontaneously Breathing Hypotensive Patients
Introduction: Inspiratory impedance technology has been shown to uniquely enhance vital organ circulation in spontaneously breathing hypotensive patients by lowering intrathoracic pressure during inspiration. The enhanced inspiratory vacuum increases cardiac preload, lowers intracranial pressure and modulates autonomic nervous system output.
Hypothesis: An impedance threshold device (ITD) is a safe and effective therapy for spontaneously breathing patients with hypotension secondary to various etiologies.
Methods: Patients >25 lbs with hypotension (systolic blood pressures [SBP] <100 mmHg [adults]; <90 mmHg [children]) secondary to various etiologies (e.g. hypovolemia, dehydration, sepsis, orthostatic intolerance, dialysis) were treated by ALS and BLS providers from a county-based EMS system with an ITD (ResQGARD® ITD 7.0; Advanced Circulatory Systems, Inc.) using either an expiratory resistance-free facemask or mouthpiece. Patients were excluded if they complained of shortness of breath, chest pain or had predefined cardiopulmonary history criteria. Patients breathed through the ITD for up to 30 minutes. Vital signs were recorded before, during and after use. IV therapy was administered if indicated but no vasopressors were given. The primary endpoint was SBP change during ITD use. A paired Students t test was used to analyze data (expressed as mean±SD).
Results: The ITD was applied to 47 patients (23 males) with an age of 62.3±20.0 years. One patient did not tolerate the ITD. A total of 39/46 patients received concurrent IV therapy. The baseline SBP (mmHg) was 81.3±11.7 before ITD use and 108.7±17.5 (p<0.001) during an average duration use of 16.4±7.3 minutes. SBP also increased from 83.0±13.8 to 103.0±11.2 mmHg in the seven patients who did not receive IV therapy (p<0.001). Diastolic BPs in both groups increased 33% and 38% respectively (p<0.05). BP increases were sustained after ITD discontinuation. The ITD was well tolerated by >95% of patients.
Conclusion: ITD use on hypotensive patients in the prehospital setting, with or without concurrent IVs, resulted in a ≥20 mmHg rise in SBP. The ITD is a safe, effective and novel therapy that ALS and BLS providers can use to rapidly and noninvasively treat hypotension due to various etiologies.