Resuscitation Outcomes Consortium (ROC) Prehospital Resuscitation Using an Impedance Valve

• Sponsor: University of Washington (Other)
• Overall Status: Terminated
• CT.gov ID: NCT00394706
• Collaborator: National Heart, Lung, and Blood Institute (NHLBI) (NIH), National Institute of Neurological Disorders and Stroke (NINDS) (NIH), Canadian Institutes of Health Research (CIHR) (Other), Defence Research and Development Canada (Industry), Heart and Stroke Foundation of Canada (Other), American Heart Association (Other)
• Enrollment: 11,738
• Locations: 9
• Arms: 4
• Duration (Months): 37
• Patients Per Site: 1304.2
• Patients Per Site Per Month: 35.3

Study Details

Study Description

Brief Summary

The purpose of this study is to look at two different treatments during a cardiac arrest that occurs outside of the hospital and whether either or both treatments will increase the number of people who live to hospital discharge. A cardiac arrest is when the heart stops pumping blood to the body.

Condition or Disease	Intervention/Treatment	Phase
Heart Arrest	Device: Impedance Threshold Device (ITD); Device: Sham ITD; Other: Analyze early; Other: Analyze later	Phase 3

Detailed Description

The first treatment involves using a device called the Impedance Threshold Device (ITD). The ITD is a small hard plastic device about the size of a fist that is attached to the face mask or airway tube used during CPR (cardiopulmonary resuscitation). The ITD provides increased blood flow back to the heart during chest compressions until the heart starts beating on its own again.

The other treatment involves the amount of CPR given before the emergency medical services (EMS) providers first look at the heart rhythm to determine if a shock is needed. A person would receive either about 30 seconds of chest compressions or about 3 minutes of compressions before checking the heart rhythm. Giving some compressions before checking the heart rhythm increases the blood being circulated to the body. Researchers do not know how many compressions before the rhythm check are necessary to save more lives.

Depending on the circumstances of the cardiac arrest a person may receive only one of these treatments or both of these treatments. The purpose of the research study is to determine if more people live when either the real ITD is used or if additional CPR is given before looking at the heart rhythm the first time. This study is being conducted in 9 different areas throughout the United States and Canada by the Resuscitation Outcomes Consortium (ROC). About 15,000 patients will be enrolled in this research study.

Study Design

• Study Type: Interventional
• Actual Enrollment: 11738 participants
• Allocation: Randomized
• Intervention Model: Factorial Assignment
• Masking: Triple (Participant, Care Provider, Investigator)
• Primary Purpose: Treatment
• Official Title: Resuscitation Outcomes Consortium (ROC) Prehospital Resuscitation Using an Impedance Valve and Early Versus Delayed Analysis
• Study Start Date: Jun 1, 2007
• Actual Primary Completion Date: Nov 1, 2009
• Actual Study Completion Date: Jul 1, 2010

Arms and Interventions

Arm	Intervention/Treatment
Experimental: 1 Use of Impedance Threshold Device (ITD)	Device: Impedance Threshold Device (ITD); Use of Impedance Threshold Device (ITD)
Sham Comparator: 2 Sham ITD	Device: Sham ITD; Sham ITD
Other: 3 Analyze early. Upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR (cardiopulmonary resuscitation) may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Other: Analyze early; Upon EMS arrival at the scene of a non-traumatic cardiac arrest, an assessment of the cardiac rhythm is done to determine whether a defibrillatory shock is required.
Other: 4 Analyze late. Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Other: Analyze later; Upon EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is given prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.

Outcome Measures

Primary Outcome Measures

1. Survival to Hospital Discharge With Satisfactory Function (Modified Rankin Scale [MRS] of Less Than or Equal to 3). [Hospital discharge or death prior to discharge]

   The modified Rankin Score (mRS) measures the ability of patients to function independently. The scale goes from 0 (no symptoms) to 6 (death). Subjects with a mRS scores of three or less (i.e. better) at the time of hospital discharge were considered to have a positive outcome, resulting in a binary measure.

Secondary Outcome Measures

1. Survival to Hospital Discharge [Survival to hospital discharge or death before discharge]

2. Modified Rankin Score at 6 Months After Hospital Discharge [6 months post hospital discharge]

   The modified Rankin Score (mRS) measures the ability of patients to function independently. The scale goes from 0 (no symptoms) to 6 (death).

3. Adult Lifestyle and Function Version of Mini-Mental Status Exam at 6 Months [6 months post hospital discharge]

   The adult lifestyle and function interview (ALFI) version of the mini-mental status exam (MMSE) measures neurological status. The ALFI-MMSE has 23 items. It is scored from 0 to 22, with lower scores interpreted as being worse.

4. Health Utilities Index III Score and Geriatric Depression Scale Score 6 Months [6 months post hospital discharge]

   The Health Utilities Index Mark 3 system was used to evaluate generic health related quality of life (HRQL). The interview-administered version of HUI3 requires completion of a maximum of 39 questions. The HUI3 consists of eight attributes of general health (vision, hearing, speech, mobility, dexterity, emotion, cognition, and pain) with five or six levels per attribute. For each respondent, health status is described as a vector that combines the levels of each attribute. This information is then converted into a utility score of HRQL on a scale from perfect health (1.0) to death (0).

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

Inclusion Criteria:

• All persons of local age of consent or older who suffer non-traumatic cardiopulmonary arrest outside of the hospital in the study communities with defibrillation and/or delivery of chest compressions provided by emergency medical service (EMS) providers dispatched to the scene and do not meet any of the exclusion criteria.

Exclusion Criteria:

Common:

• Do not attempt resuscitation (DNAR) orders

• Blunt, penetrating, or burn-related injury

• Patients with exsanguinations

• Known prisoners

• Known pregnancy

• Non-ROC EMS agency/provider

For Analyzing Late versus Early

• EMS-witnessed arrests

• Non-EMS rhythm analysis (AED placed by police or lay responder is an exclusion but CPR by lay or other non-EMS responders is not)

For ITD:

• Tracheostomy present

• CPR performed with the mechanical compression "Autopulse" device.

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Alabama Resuscitation Center	Birmingham	Alabama	United States	35294
2	UCSD-San Diego Resuscitation Center	San Diego	California	United States	92103
3	Portland Resuscitation Outcomes Consortium, Oregon Health & Sciences University	Portland	Oregon	United States	97239
4	The Pittsburgh Resuscitation Network, University of Pittsburgh	Pittsburgh	Pennsylvania	United States	15213
5	Dallas Center for Resuscitation Research, University of Texas Southwestern Medical Center	Dallas	Texas	United States	75390
6	Seattle-King County Center for Resuscitation Research, University of Washington	Seattle	Washington	United States	98195
7	Milwaukee Resuscitation Network, Medical College of Wisconsin	Milwaukee	Wisconsin	United States	53226
8	University of Ottawa/University of British Columbia Collaborative RCC, Ottawa Health Research	Ottawa	Ontario	Canada	K1Y4E9
9	Toronto Regional Resuscitation Research Out-of-Hospital Network, University of Toronto	Toronto	Ontario	Canada	M5B1W8

Sponsors and Collaborators

• University of Washington
• National Heart, Lung, and Blood Institute (NHLBI)
• National Institute of Neurological Disorders and Stroke (NINDS)
• Canadian Institutes of Health Research (CIHR)
• Defence Research and Development Canada
• Heart and Stroke Foundation of Canada
• American Heart Association

Investigators

• Study Chair: Myron L Weisfeldt, MD, Johns Hopkins University

Study Documents (Full-Text)

None provided.

More Information

Additional Information:

• Click here for more information about the ROC PRIMED Trial

Publications

• Aufderheide TP, Nichol G, Rea TD, Brown SP, Leroux BG, Pepe PE, Kudenchuk PJ, Christenson J, Daya MR, Dorian P, Callaway CW, Idris AH, Andrusiek D, Stephens SW, Hostler D, Davis DP, Dunford JV, Pirrallo RG, Stiell IG, Clement CM, Craig A, Van Ottingham L, Schmidt TA, Wang HE, Weisfeldt ML, Ornato JP, Sopko G; Resuscitation Outcomes Consortium (ROC) Investigators. A trial of an impedance threshold device in out-of-hospital cardiac arrest. N Engl J Med. 2011 Sep 1;365(9):798-806. doi: 10.1056/NEJMoa1010821.

• Responsible Party: Susanne May, Principal Investigator, University of Washington
• ClinicalTrials.gov Identifier: NCT00394706
• Other Study ID Numbers: 29919; HL077863
• First Posted: Nov 1, 2006
• Last Update Posted: Aug 9, 2018
• Last Verified: Jul 1, 2018

• Keywords provided by Susanne May, Principal Investigator, University of Washington: cardiac arrest; cardiopulmonary resuscitation
• Additional relevant MeSH terms: Heart Arrest

Study Results

Participant Flow

Recruitment Details	Clinical sites enrolled patients during a run-in period with the first patient enrolled on June 7, 2007. The run-in period ranged from from 2 to 6 months across the sites. The last patient was enrolled in the evaluable phase on November 6, 2009. All patients were enrolled in the pre-hospital EMS setting.

Arm/Group Title	Analyze Early + ITD	Analyze Early + Sham	Analyze Early, Not in ITD vs Sham	Analyze Later + ITD	Analyze Later + Sham	Analyze Later, Not in ITD vs. Sham	Not in AEvAL, ITD Device	Not in AEvAL, Sham
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR (cardiopulmonary resuscitation) may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of ITD (Impedance Threshold Device) by EMS providers in the prehospital setting.	Analyze early: upon EMS arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of a sham ITD by EMS providers in the pre-hospital setting.	Analyze early. Upon EMS arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Neither an ITD nor sham device used.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of a sham ITD by EMS providers in the pre-hospital setting.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Neither an ITD nor sham device used.	Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, local policy determines the length of CPR done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Impedance Threshold Device used by EMS providers in the pre-hospital setting.	Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, local policy determines the length of CPR done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Sham ITD used by EMS providers in the pre-hospital setting.
Period Title: Overall Study
STARTED	1819	1862	1624	1633	1636	1384	929	851
COMPLETED	1815	1860	1615	1632	1634	1377	926	851
NOT COMPLETED	4	2	9	1	2	7	3	0

Baseline Characteristics

Arm/Group Title	Analyze Early + ITD	Analyze Early + Sham	Analyze Early, Not in ITD vs Sham	Analyze Later + ITD	Analyze Later + Sham	Analyze Later, Not in ITD vs. Sham	Not in AEvAL, ITD Device	Not in AEvAL, Sham	Total
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR (cardiopulmonary resuscitation) may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of ITD (Impedance Threshold Device) by EMS providers in the prehospital setting.	Analyze early: upon EMS arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of a sham ITD by EMS providers in the pre-hospital setting.	Analyze early. Upon EMS arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Neither an ITD nor sham device used.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of a sham ITD by EMS providers in the pre-hospital setting.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Neither an ITD nor sham device used.	Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, local policy determines the length of CPR done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Impedance Threshold Device used by EMS providers in the pre-hospital setting.	Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, local policy determines the length of CPR done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Sham ITD used by EMS providers in the pre-hospital setting.	Total of all reporting groups
Overall Participants	1817	1861	1621	1631	1633	1379	929	851	11722
Age (Count of Participants)
<=18 years	1 0.1%	2 0.1%	2 0.1%	1 0.1%	4 0.2%	0 0%	1 0.1%	0 0%	11 0.1%
Between 18 and 65 years	734 40.4%	809 43.5%	687 42.4%	693 42.5%	675 41.3%	590 42.8%	381 41%	370 43.5%	4939 42.1%
>=65 years	1082 59.5%	1050 56.4%	932 57.5%	937 57.4%	954 58.4%	789 57.2%	547 58.9%	481 56.5%	6772 57.8%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	67.3 (16.3)	66.6 (16.4)	66.3 (17.0)	67.2 (16.6)	67.1 (16.4)	66.3 (16.7)	67.7 (16.3)	66.7 (16.7)	66.9 (16.6)
Sex: Female, Male (Count of Participants)
Female	609 33.5%	673 36.2%	605 37.3%	615 37.7%	578 35.4%	486 35.2%	313 33.7%	303 35.6%	4182 35.7%
Male	1208 66.5%	1188 63.8%	1016 62.7%	1016 62.3%	1055 64.6%	893 64.8%	616 66.3%	548 64.4%	7540 64.3%
Region of Enrollment (participants) [Number]
United States	733 40.3%	764 41.1%	411 25.4%	691 42.4%	698 42.7%	400 29%	534 57.5%	489 57.5%	4720 40.3%
Canada	1084 59.7%	1097 58.9%	1210 74.6%	940 57.6%	935 57.3%	979 71%	395 42.5%	362 42.5%	7002 59.7%

Outcome Measures

1. Primary Outcome

Title	Survival to Hospital Discharge With Satisfactory Function (Modified Rankin Scale [MRS] of Less Than or Equal to 3).
Description	The modified Rankin Score (mRS) measures the ability of patients to function independently. The scale goes from 0 (no symptoms) to 6 (death). Subjects with a mRS scores of three or less (i.e. better) at the time of hospital discharge were considered to have a positive outcome, resulting in a binary measure.
Time Frame	Hospital discharge or death prior to discharge

Outcome Measure Data

Analysis Population Description

Analyses of both interventions excluded subjects who suffered arrest secondary to drowning, strangulation, or electrocution; or for whom the primary outcome was unknown. Additionally, the ITD vs. Sham analysis excluded subjects who did not have the device applied, had study exclusions, or who had a response time of more than 15 minutes.

Arm/Group Title	Analyze Early	Analyze Later	Active ITD	Sham ITD
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Sham ITD used by EMS providers in the pre-hospital setting.
Measure Participants	5290	4643	4373	4345
Number [participants]	310 17.1%	273 14.7%	254 15.7%	260 15.9%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Analyze Early, Analyze Later
	Comments	Comparison of the rates of MRS <=3 in Analyze Early vs. Analyze Later arms using a linear mixed effect model with an identity link and random effects to account for the cluster randomization.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.59
	Comments	Two sided test with an a priori threshold of 0.05 for declaring statistical significance.
	Method	Mixed Models Analysis
	Comments
Method of Estimation	Estimation Parameter	Risk Difference (RD)
	Estimated Value	-0.2
	Confidence Interval	(2-Sided) 95%; -1.1 to 0.7
	Parameter Dispersion	Type: Value:
	Estimation Comments	Estimate of the rate of MRS <= 3 in Analyze Later arm minus rate in Analyze early arm.

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Active ITD, Sham ITD
	Comments	Comparison of the rates of MRS <=3 in Active ITD and Sham treatment arms, adjusted for sequential monitoring.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.71
	Comments	To adjust for group sequential monitoring, the point estimate was bias-adjusted (Whitehead 1986) and confidence intervals and P values calculated from the maximum likelihood based ordering of the outcome(Emerson and Fleming, 1990)
	Method	t-test, 2 sided
	Comments
Method of Estimation	Estimation Parameter	Risk Difference (RD)
	Estimated Value	-0.1
	Confidence Interval	(2-Sided) 95%; -1.1 to 0.8
	Parameter Dispersion	Type: Value:
	Estimation Comments	Estimate of the rate of MRS <= 3 in the active ITD arm minus the rate in the Sham ITD arm.

2. Secondary Outcome

Title	Survival to Hospital Discharge
Time Frame	Survival to hospital discharge or death before discharge

Outcome Measure Data

Analysis Population Description

Analyses of both interventions excluded subjects who suffered arrest secondary to drowning, strangulation, or electrocution; or for whom the primary outcome was unknown. Additionally, the ITD vs. Sham analysis excluded subjects who did not have the device applied, had study exclusions, or who had a response time of more than 15 minutes.

Arm/Group Title	Analyze Early	Analyze Later	Active ITD	Sham ITD
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Sham ITD used by EMS providers in the pre-hospital setting.
Measure Participants	5290	4643	4373	4345
Number [participants]	427 23.5%	372 20%	357 22%	355 21.8%

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Analyze Early, Analyze Later
	Comments	Comparison of the rates of survival to hospital discharge in Analyze Early vs. Analyze Later arms using a generalized estimating equations model with an identity link, grouping on cluster.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.92
	Comments	Two sided test with an a priori threshold of 0.05 for declaring statistical significance.
	Method	GEE
	Comments
Method of Estimation	Estimation Parameter	Risk Difference (RD)
	Estimated Value	-0.1
	Confidence Interval	(2-Sided) 95%; -1.2 to 1.1
	Parameter Dispersion	Type: Value:
	Estimation Comments	Estimate of the rate of survival to hospital discharge in Analyze Later arm minus rate in Analyze early arm.

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Active ITD, Sham ITD
	Comments	Comparison of the rates of survival to hospital discharge in Active ITD and Sham treatment arms.
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	0.99
	Comments
	Method	t-test, 2 sided
	Comments
Method of Estimation	Estimation Parameter	Risk Difference (RD)
	Estimated Value	0.0
	Confidence Interval	(2-Sided) 95%; -1.2 to 1.1
	Parameter Dispersion	Type: Value:
	Estimation Comments	Estimate of the rate of survival to hospital discharge in the active ITD arm minus rate in the Sham ITD arm.

3. Secondary Outcome

Title	Modified Rankin Score at 6 Months After Hospital Discharge
Description	The modified Rankin Score (mRS) measures the ability of patients to function independently. The scale goes from 0 (no symptoms) to 6 (death).
Time Frame	6 months post hospital discharge

Outcome Measure Data

Analysis Population Description

ITT population, survived to hospital discharge, consented to participate in the post-discharge substudy, and with at least one post-discharge assessment.

Arm/Group Title	Analyze Early	Analyze Later	Active ITD	Sham ITD
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Sham ITD used by EMS providers in the pre-hospital setting.
Measure Participants	308	274	218	223
Mean (Standard Deviation) [units on a scale]	1.7 (1.8)	1.8 (1.8)	1.8 (1.9)	1.6 (1.7)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Analyze Early, Analyze Later
	Comments	Linear regression was used to assess associations between post-discharge measures and treatment group comparisons with adjustment for baseline characteristics. Site was adjusted for to accommodate clustering of patients within sites. All regression analyses used robust standard errors to accommodate non-constant variances.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.07
	Confidence Interval	(2-Sided) 95%; -0.20 to 0.34
	Parameter Dispersion	Type: Value:
	Estimation Comments	Mean MRS for Analyze Later minus mean MRS for Analyze Early (i.e. positive values favor Analyze Later).

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Active ITD, Sham ITD
	Comments	Linear regression was used to assess associations between post-discharge measures and treatment group comparisons with adjustment for baseline characteristics. Site was adjusted for to accommodate clustering of patients within sites. All regression analyses used robust standard errors to accommodate non-constant variances.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.14
	Confidence Interval	(2-Sided) 95%; -0.17 to 0.44
	Parameter Dispersion	Type: Value:
	Estimation Comments	Mean MRS for Active ITD minus mean MRS for Sham ITD (i.e. positive values favor the active device).

4. Secondary Outcome

Title	Adult Lifestyle and Function Version of Mini-Mental Status Exam at 6 Months
Description	The adult lifestyle and function interview (ALFI) version of the mini-mental status exam (MMSE) measures neurological status. The ALFI-MMSE has 23 items. It is scored from 0 to 22, with lower scores interpreted as being worse.
Time Frame	6 months post hospital discharge

Outcome Measure Data

Analysis Population Description

ITT population, survived to hospital discharge, consented to participate in the post-discharge substudy, and with at least one post-discharge assessment.

Arm/Group Title	Analyze Early	Analyze Later	Active ITD	Sham ITD
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Sham ITD used by EMS providers in the pre-hospital setting.
Measure Participants	318	265	214	226
Mean (Standard Deviation) [units on a scale]	18.3 (6.0)	18.5 (5.5)	18.0 (6.3)	18.7 (5.5)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Analyze Early, Analyze Later
	Comments	Linear regression was used to assess associations between post-discharge measures and treatment group comparisons with adjustment for baseline characteristics. Site was adjusted for to accommodate clustering of patients within sites. All regression analyses used robust standard errors to accommodate non-constant variances.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.06
	Confidence Interval	(2-Sided) 95%; -0.71 to 0.83
	Parameter Dispersion	Type: Value:
	Estimation Comments	Mean ALFI-MMSE for Analyze Later minus mean ALFI-MMSE for Analyze Early (i.e. positive values favor Analyze Later).

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Active ITD, Sham ITD
	Comments	Linear regression was used to assess associations between post-discharge measures and treatment group comparisons with adjustment for baseline characteristics. Site was adjusted for to accommodate clustering of patients within sites. All regression analyses used robust standard errors to accommodate non-constant variances.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	-0.66
	Confidence Interval	(2-Sided) 95%; -1.61 to 0.28
	Parameter Dispersion	Type: Value:
	Estimation Comments	Mean ALFI-MMSE for Active ITD minus mean ALFI-MMSE for Sham ITD (i.e. positive values favor the active device).

5. Secondary Outcome

Title	Health Utilities Index III Score and Geriatric Depression Scale Score 6 Months
Description	The Health Utilities Index Mark 3 system was used to evaluate generic health related quality of life (HRQL). The interview-administered version of HUI3 requires completion of a maximum of 39 questions. The HUI3 consists of eight attributes of general health (vision, hearing, speech, mobility, dexterity, emotion, cognition, and pain) with five or six levels per attribute. For each respondent, health status is described as a vector that combines the levels of each attribute. This information is then converted into a utility score of HRQL on a scale from perfect health (1.0) to death (0).
Time Frame	6 months post hospital discharge

Outcome Measure Data

Analysis Population Description

ITT population, survived to hospital discharge, consented to participate in the post-discharge substudy, and with at least one post-discharge assessment.

Arm/Group Title	Analyze Early	Analyze Later	Active ITD	Sham ITD
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required.	Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.	Sham ITD used by EMS providers in the pre-hospital setting.
Measure Participants	273	240	191	189
Mean (Standard Deviation) [units on a scale]	0.74 (0.34)	0.73 (0.35)	0.71 (0.36)	0.75 (0.33)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Analyze Early, Analyze Later
	Comments	Linear regression was used to assess associations between post-discharge measures and treatment group comparisons with adjustment for baseline characteristics. Site was adjusted for to accommodate clustering of patients within sites. All regression analyses used robust standard errors to accommodate non-constant variances.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	0.00
	Confidence Interval	(2-Sided) 95%; -0.06 to 0.05
	Parameter Dispersion	Type: Value:
	Estimation Comments	Mean HUI for Analyze Later minus mean HUI for Analyze Early (i.e. positive values favor Analyze Later).

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Active ITD, Sham ITD
	Comments	Linear regression was used to assess associations between post-discharge measures and treatment group comparisons with adjustment for baseline characteristics. Site was adjusted for to accommodate clustering of patients within sites. All regression analyses used robust standard errors to accommodate non-constant variances.
	Type of Statistical Test	Superiority
	Comments
Statistical Test of Hypothesis	p-Value
	Comments
	Method
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	-0.02
	Confidence Interval	(2-Sided) 95%; -0.08 to 0.05
	Parameter Dispersion	Type: Value:
	Estimation Comments	Mean HUI for Active ITD minus mean HUI for Sham ITD (i.e. positive values favor the active device).

Adverse Events

Arm/Group Title	Analyze Early + ITD		Analyze Early + Sham		Analyze Early, Not in ITD vs Sham		Analyze Later + ITD		Analyze Later + Sham		Analyze Later, Not in ITD vs. Sham		Not in AEvAL, ITD Device		Not in AEvAL, Sham
Arm/Group Description	Analyze early: upon EMS (emergency medical services) arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR (cardiopulmonary resuscitation) may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of ITD (Impedance Threshold Device) by EMS providers in the prehospital setting.		Analyze early: upon EMS arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of a sham ITD by EMS providers in the pre-hospital setting.		Analyze early. Upon EMS arrival at the scene of a non-traumatic cardiac arrest, the EMS providers assess the cardiac rhythm as soon as possible. Approximately thirty seconds of CPR may be done prior to an assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Neither an ITD nor sham device used.		Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of Impedance Threshold Device by EMS providers in the pre-hospital setting.		Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Use of a sham ITD by EMS providers in the pre-hospital setting.		Analyze later: upon the EMS arrival at the scene of a non-traumatic cardiac arrest, three minutes of CPR is done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Neither an ITD nor sham device used.		Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, local policy determines the length of CPR done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Impedance Threshold Device used by EMS providers in the pre-hospital setting.		Upon the EMS arrival at the scene of a non-traumatic cardiac arrest, local policy determines the length of CPR done prior to the assessment of the cardiac rhythm to determine whether a defibrillatory shock is required. Sham ITD used by EMS providers in the pre-hospital setting.
All Cause Mortality
	Analyze Early + ITD		Analyze Early + Sham		Analyze Early, Not in ITD vs Sham		Analyze Later + ITD		Analyze Later + Sham		Analyze Later, Not in ITD vs. Sham		Not in AEvAL, ITD Device		Not in AEvAL, Sham
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)		/ (NaN)
Serious Adverse Events
	Analyze Early + ITD		Analyze Early + Sham		Analyze Early, Not in ITD vs Sham		Analyze Later + ITD		Analyze Later + Sham		Analyze Later, Not in ITD vs. Sham		Not in AEvAL, ITD Device		Not in AEvAL, Sham
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	154/2310 (6.7%)		193/2321 (8.3%)		122/2051 (5.9%)		166/2156 (7.7%)		174/2191 (7.9%)		121/1839 (6.6%)		181/1336 (13.5%)		152/1278 (11.9%)
Hepatobiliary disorders
Liver lacerations	0/2310 (0%)	0	0/2321 (0%)	0	0/2051 (0%)	0	0/2156 (0%)	0	0/2191 (0%)	0	0/1839 (0%)	0	0/1336 (0%)	0	1/1278 (0.1%)	1
Respiratory, thoracic and mediastinal disorders
Airway bleeding	62/2310 (2.7%)	64	79/2321 (3.4%)	79	28/2051 (1.4%)	28	67/2156 (3.1%)	67	67/2191 (3.1%)	69	26/1839 (1.4%)	28	60/1336 (4.5%)	61	51/1278 (4%)	51
Pulmonary edema	98/2310 (4.2%)	99	120/2321 (5.2%)	121	98/2051 (4.8%)	98	104/2156 (4.8%)	104	118/2191 (5.4%)	118	99/1839 (5.4%)	101	134/1336 (10%)	135	108/1278 (8.5%)	109
Skin and subcutaneous tissue disorders
Defibrillator burns to chest	0/2310 (0%)	0	0/2321 (0%)	0	1/2051 (0%)	1	0/2156 (0%)	0	0/2191 (0%)	0	0/1839 (0%)	0	0/1336 (0%)	0	0/1278 (0%)	0
Other (Not Including Serious) Adverse Events
	Analyze Early + ITD		Analyze Early + Sham		Analyze Early, Not in ITD vs Sham		Analyze Later + ITD		Analyze Later + Sham		Analyze Later, Not in ITD vs. Sham		Not in AEvAL, ITD Device		Not in AEvAL, Sham
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/2310 (0%)		0/2321 (0%)		0/2051 (0%)		0/2156 (0%)		0/2191 (0%)		0/1839 (0%)		0/1336 (0%)		0/1278 (0%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.