Abstract 63: Use of an Impedance Threshold Device in Hypotensive Patients in the Emergency Department.
Background: Hypotension is a common finding in patients who present to the emergency department. By increasing venous return, an impedance inspiratory threshold device (ITD) has been shown to increase systolic blood pressure (SBP) and survival rates in animals in shock, and to increase SBP in humans with orthostatic hypotension as well as dialysis patients with intradialytic hypotension. We evaluated the use of an ITD attached to a facemask in spontaneously breathing hypotensive patients to determine its effect on SBP when used in conjunction with standard therapy.
Methods: Following consent, patients with a SBP ≤ 95 mm Hg were randomized in a double blind controlled trial to breathe for 10 min through one of two devices: an ITD designed to open at an inspiratory pressure of -6 cm H2O or a sham device with no inspiratory resistance. Patients were excluded for dyspnea, chest pain, cardiopulmonary disease, or altered mental status. Standard therapy was delivered including use of O2 through the ITD and intravenous crystalloid solution as determined by the attending physician. SBP was measured before, during, and after use.
Results: Baseline SBP and heart rates were similar in the active ITD (n=15) and sham control (n=18) patients. Maximum SBP was increased 12 ± 8 mmHg with the active ITD vs 5 ± 6 mmHg with the sham device (p<0.01), with no significant change in heart rate from baseline. Four additional patients felt claustrophobic and could not tolerate breathing through the active ITD. There were no adverse events associated with ITD use.
Conclusions: Use of an ITD in hypotensive patients in the emergency department resulted in a rapid increase in SBP compared with a sham device in control patients. This device provides an easily applied adjunctive therapy for spontaneously breathing hypotensive patients, without adverse effects.