Evaluation of an impedance threshold device in patients receiving active compression-decompression cardiopulmonary resuscitation for out of hospital cardiac arrest

University of Minnesota Duluth, Duluth, Minnesota, United States
Resuscitation (Impact Factor: 4.17). 07/2004; 61(3):265-71. DOI: 10.1016/j.resuscitation.2004.01.032
Source: PubMed


The purpose of this multicentre clinical randomized controlled blinded prospective trial was to determine whether an inspiratory impedance threshold device (ITD), when used in combination with active compression-decompression (ACD) cardiopulmonary resuscitation (CPR), would improve survival rates in patients with out-of-hospital cardiac arrest.
Patients were randomized to receive either a sham (n = 200) or an active impedance threshold device (n = 200) during advanced cardiac life support performed with active compression-decompression cardiopulmonary resuscitation. The primary endpoint of this study was 24 h survival. The 24 h survival rates were 44/200 (22%) with the sham valve and 64/200 (32%) with the active valve (P = 0.02). The number of patients who had a return of spontaneous circulation (ROSC), intensive care unit (ICU) admission, and hospital discharge rates was 77 (39%), 57 (29%), and 8 (4%) in the sham valve group versus 96 (48%) (P = 0.05), 79 (40%) (P = 0.02), and 10 (5%) (P = 0.6) in the active valve group. Six out of ten survivors in the active valve group and 1/8 survivors in the sham group had normal neurological function at hospital discharge (P = 0.1).
The use of an impedance valve in patients receiving active compression-decompression cardiopulmonary resuscitation for out-of-hospital cardiac arrest significantly improved 24 h survival rates.

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    • "Included studies were published between 2000 and 2011 [11,12, 22,23,24,25,26], varying in size between 21 and 8,718 subjects (Table 1) [12, 22], with follow-up limited to the emergency or hospital setting in all but three reports [11, 22, 25]. Study quality was in general high. "
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    ABSTRACT: Introduction Uncertainty persists on the clinical impact of impedance threshold devices in out-of-hospital cardiac arrest. We conducted an updated systematic review on impedance threshold devices. Methods Several databases were searched for studies testing the effectiveness of impedance threshold devices in patients with cardiac arrest. The primary endpoint was long-term survival. Results Seven trials (11,254 patients) were included. In 4 studies (2,284 patients) impedance threshold devices were used with active compression-decompression-cardiopulmonary resuscitation, and in the others alone. Overall, impedance threshold devices did not impact on the rate of return of spontaneous circulation (odds ratio=1.17 [0.96-1.43], p=0.114), favorable neurologic outcome (odds ratio=1.56 [0.97-2.50], p=0.065), or long-term survival (odds ratio=1.22 [0.94-1.58], p=0.127). These analyses were fraught with heterogeneity (respectively, p=0.055, p=0.236, and p=0.011) and inconsistency (respectively, I-squared=51% , I-squared=27% , and I-squared=67%). Exploratory analysis showed that combined use of impedance threshold devices with active compression-decompression significantly increased the likelihood of return of spontaneous circulation (odds ratio=1.19 [1.00-1.40], p=0.045), favorable neurologic outcome (odds ratio=1.60 [1.14-2.25], p=0.006), and long-term survival (odds ratio=1.52 [1.11-2.08], p=0.009). The favorable impact of the interaction between impedance threshold devices and active compression-decompression was also confirmed at meta-regression analysis (respectively, b=0.195 [0.004-0.387], p=0.045, b=0.500 [0.079-0.841], p=0.018, b=0.413 [0.063-0.764], p=0.021). Conclusions The evidence base on impedance threshold devices is apparently inconclusive, with a neutral impact on clinically relevant outcomes. However, exploratory analysis focusing on the combined use of impedance threshold devices with active compression-decompression suggests that this combo treatment may be useful to improve patient prognosis.
    03/2014; 6(2):105-13.
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    • "Intrigued by the positive results of recent studies combining the ITD with active compression decompression CPR [12] [13] [14], we have also recently begun to explore whether adding an ITD to the performance of ACD CPR with an automated device that actively compresses and decompresses the chest would further improve short-term survival rates in our EMS system. We intend to continue to study this treatment combination as we try to improve the quality of care for our cardiac arrest patients. "
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    ABSTRACT: An impedance threshold device (ITD) has been developed for the treatment of cardiac arrest to augment circulation to the heart and brain during cardiopulmonary resuscitation (CPR). The ITD has ventilation timing lights that flash at 12 min(-1) to discourage excessive ventilation rates. Implementation of the ITD during conventional manual CPR in a large emergency medical services (EMS) system (Staffordshire, UK) is safe, feasible and will improve short-term survival. ITD use was implemented by the Staffordshire Ambulance Trust, which treats 1600 cardiac arrests per year with 90 advanced life support (ALS) units and an average response time of 6.3 min. During training, rescuers learned to use the ventilation timing lights to discourage hyperventilation. Rescuers applied the device after tracheal intubation. They were trained to allow the chest to recoil fully after each compression. Prospective ITD use in adults receiving conventional manual CPR for non-traumatic cardiac arrest was compared to matched historical controls receiving conventional manual CPR without inspiratory impedance. All received similar ALS care. The primary endpoint was admission to the emergency department (ED) alive following cardiac arrest. Chi-square, Fisher's exact and Kolmogorov-Smirnov tests were used for statistical analyses. Survival (alive upon ED admission) in all patients receiving an ITD (61/181 [34%]) improved by 50% compared to historical controls (180/808 [22%]) (P<0.01). Survival in patients presenting in asystole tripled in the group receiving an ITD (26/76 [34%]) compared with historical controls (39/351 [11%]) (P=0.001). There were no significant adverse events. The ITD was used safely and effectively in a large, diverse EMS system and markedly improved short-term survival for adult patients in non-traumatic cardiac arrest.
    Resuscitation 11/2005; 67(1):103-8. DOI:10.1016/j.resuscitation.2005.05.009 · 4.17 Impact Factor
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    • "doi:10.1016/j.resuscitation.2004.12.027 compression–decompression (ACD) CPR increases blood flow to the heart and brain [1] [2] [3] [4] and increases 24-h survival and improves neurological recovery [5]. Studies have also shown the benefit of an ITD on hemodynamics and shortand longer-term outcomes in humans receiving ACD CPR [6] [7] [8]. To date, there are no published reports on the hemodynamic effects of using the ITD during conventional CPR in humans. "
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    ABSTRACT: In animals in cardiac arrest, an inspiratory impedance threshold device (ITD) has been shown to improve hemodynamics and neurologically intact survival. The objective of this study was to determine whether an ITD would improve blood pressure (BP) in patients receiving CPR for out-of-hospital cardiac arrest. This prospective, randomized, double-blind, intention-to-treat study was conducted in the Milwaukee, WI, emergency medical services (EMS) system. EMS personnel used an active (functional) or sham (non-functional) ITD on a tracheal tube on adults in cardiac arrest of presumed cardiac etiology. Care between groups was similar except for ITD type. Low dose epinephrine (1mg) was used per American Heart Association Guidelines. Femoral arterial BP (mmHg) was measured invasively during CPR. Mean+/-S.D. time from ITD placement to first invasive BP recording was approximately 14 min. Twelve patients were treated with a sham ITD versus 10 patients with an active ITD. Systolic BPs (mean+/-S.D.) [number of patients treated at given time point] at T = 0 (time of first arterial BP measurement), and T=2, 5 and 7 min were 85+/-29 [10], 85+/-23 [10], 85+/-16 [9] and 69+/-22 [8] in the group receiving an active ITD compared with 43+/-15 [12], 47+/-16 [12], 47+/-20 [9], and 52+/-23 [9] in subjects treated with a sham ITD, respectively (p < 0.01 for all times). Diastolic BPs at T = 0, 2, 5 and 7 min were 20+/-12, 21+/-13, 23+/-15 and 25+/-14 in the group receiving an active ITD compared with 15+/-9, 17+/-8, 17+/-9 and 19+/-8 in subjects treated with a sham ITD, respectively (p = NS for all times). No significant adverse device events were reported. Use of the active ITD was found to increase systolic pressures safely and significantly in patients in cardiac arrest compared with sham controls.
    Resuscitation 07/2005; 66(1):13-20. DOI:10.1016/j.resuscitation.2004.12.027 · 4.17 Impact Factor
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