Medical Student Research Fellowship for Summer 2007

Mentor: Lynn P. Roppolo
Department: Emergency Medicine
Room number: Parkland, Emergency Medicine Residency Administration
Mail Code: 8579
Phone number: 214-590-1350
E-mail: lynn.roppolo@utsouthwestern.edu

Project title: The Impedance Threshold Device (ITD) for acute hypovolemic hypotension in the emergency department (ED).

Human subjects IRB approved project number (where applicable): 012005-065

Project Type: Patient Based Research

Brief Description of Project: The purpose of the study is to determine if the ITD attached to a facemask or mouthpiece can increase blood pressure in patients who present to the emergency department with hypotension secondary to hypovolemia or relative hypovolemia.

Role of Medical Student: The student will screen patients in the ED to determine whether they meet study inclusion criteria and enrolling patients into the study. We anticipate screening about 10 patients/day and enrolling 1 to 2 patients/day. We hope to enroll at least 30 patients by the end of the summer research program. The student will collect additional data from the hospital chart 24 hours after admission. The student will record original patient measurements and data from the hospital chart, enter data into a database, analyze data, and produce a report in the form of an abstract and co-author a manuscript. The primary end-point for the study is response of blood pressure during use of the ITD for a 10-minute period.

Previous Research Activities or Publications with Medical Students (Students are in bold):

Kleinschmidt K, Roppolo L, Chavez C, Hayes R, Mesarwi O, Schaefer J, Wald R, Westfall A, Zaremba J, DeLemos J.Creation of a Databank of Patients with Possible Acute Coronary Syndromes (ACS): Characteristics, Demographics, and Serum Markers. Presented at the University of Texas Southwestern Medical Student Research Forum, January 2006, Dallas, Texas.

Roppolo LP, Ohman K, Pepe PE, Idris AH. The effectiveness of a short cardiopulmonary resuscitation course for laypersons. Circulation October 25 2005;112 (supplement II):325-326 (abstract 1627). Presented at the Annual Meeting of the American Heart Association, November 13, 2005, Dallas TX.

Idris AH, Roppolo LP, Ohman K, Pepe PE. A five-minute training program for automated external defibrillator use is more effective than a 4-hour course. Circulation October 25 2005;112 (supplement II):326 (abstract 1628). Presented at the Annual Meeting of the American Heart Association, November 13, 2005, Dallas TX.
Roppolo LP, Abele T, Martinez, B, White P, Klein KW, Minhajuddin ATM. A prospective study comparing standard laryngoscopy to the TrachView Fiberoptic System for tracheal visualization. Academic Emergency Medicine 2005;12: Accepted for presentation at the Society for Academic Emergency Medicine annual meeting in New York City, May 2005 and presented at the Texas College of Emergency Physicians' Annual Meeting, April 2005.

Roppolo L, Pepe P, Westfall A, Idris A, Wigginton J. Identification of agonal breathing by dispatchers to improve the detection and treatment of cardiac arrest. Crit Care March 2005; 9 (supplement 1):127.. Presented at the 25th International Congress on Intensive Care and Emergency Medicine, March 22, 2005, Brussels, Belgium.

Pepe PE, Roppolo LP, Westfall A and Idris AH. Assessment of agonal breathing improves the detection of cardiac arrest. Proceedings of the VIII Wolf Creek Conference on Resuscitation. Presented at the VIII Wolf Creek Conference, June 12, 2005, Palm Springs, CA

Roppolo LP, Westfall A, Pepe PE, Idris AH. Assessment of agonal breathing improves detection of cardiac arrest. Circulation October 26, 2004;110 (17) supplement III: III-456 (abstract). Presented at the Annual Scientific Sessions of the American Heart Association, Monday, Nov 8, 2004 in New Orleans, LA.

Roppolo LP, Hatten B, Brockman CR, Hynan LS, Waggenspack W, Martinez J. A prospective study comparing standard laryngoscopy to the Trachview Videoscope System for orotracheal intubation by emergency medicine residents and medical students. Ann Emerg Med 2004;43: Presented at the ACEP Scientific Assembly, October 2004.

ITD Project Summary

PURPOSE: The purpose of the study is to determine if the Impedance Threshold Device (ITD) attached to a facemask or mouthpiece can increase blood pressure in patients who present to the emergency department with hypotension secondary to hypovolemia or relative hypovolemia. The study is designed to test the hypothesis that use of the active ITD will result in a rapid rise in blood pressure secondary to an increase in cardiac output. Either an active or sham ITD will be applied to hypotensive patients who present to the emergency department with an initial systolic blood pressure of <95 mm Hg. The main endpoint of this portion of the study will be the rise in blood pressure over the first 10 minutes of time. Multiple additional clinical parameters will also be compared between the two groups of patients.
Patients in this study will still receive the current standard of care for hypotension, which currently consists of controlling the bleeding, reversing other potential causes of low blood pressure such as correcting hyperthermia, and administering fluids and/or blood products as appropriate.

CONCISE SUMMARY OF PROJECT:
Once it has been determined that the subjects meet enrollment criteria based upon the inclusion and exclusion criteria, and informed consent is obtained, subjects will be randomized to either a sham ITD or an active (functional) ITD. The sham and active ITDs look identical. The devices will be kept in an opaque package, preventing anyone involved with the study from knowing whether any given device is a sham or active ITD based upon visual inspection. Baseline blood pressure, heart rate, respiratory rate, oxygen saturation, and clinical findings including quality of the pulse and quality of respirations will be recorded immediately. The facemask or mouthpiece/ITD will then be placed and hemodynamic parameters will be assessed every 2 minutes for a minimum of ten minutes. Researchers and subjects will be blinded regarding use of either an active or sham device. All devices will be coded in advance and none of the investigators will be aware of the code until after the patient enrollment is complete. Physiological parameters will continue to be assessed for a minimum of fifteen minutes. Standard therapies, including intravenous fluids, will be administered as deemed clinically necessary, regardless of the effect of the ITD. Patients will be encouraged to use the ITD after the initial ten-minute application as long as their systolic blood pressure remains <100 mmHg, up to 30 minutes. A number of key clinical parameters, as shown in Table 1, will be monitored and recorded.
Table 1. Key clinical parameters to be measured
Primary endpoint Change in systolic blood pressure over first 10 minutes of therapy. Blood pressure will be measured by cuff every 2 minutes
Secondary endpoints Heart rate recorded every 2 minutes, respiratory rate recorded every 5 minutes, quality of radial pulse, oxygen saturation measured transcutaneous and recorded every 5 minutes, arterial blood gases (pH, pO2, pCO2, base excess) when measured as part of routine care, initial hematocrit and hemoglobin, hematocrit and hemoglobin 1 and 6 hours after presentation to the ER, serum lactate, time to systolic blood pressure >100 mmHg, type and quantity of fluid administration, intubation rate, device tolerance, adverse event and complication rates, estimated blood loss in hypotension secondary to blood loss, time to discharge to floor , and final disposition

Physiological measurements: Continuous heart rate will be measured from an ECG monitor. Systolic and diastolic arterial blood pressures will be measured non-invasively with an automated sphygmomanometer blood pressure measurement device. Respiratory rate will be assessed by nursing personnel. Quality of the radial artery pulse pressure and respiratory effort is also assessed routinely by nursing personnel. While subjective, this important clinical parameter is often all that is available in the field to determine what interventions are going to be used in a wounded soldier.
Data analysis:
The active and sham ITD will be compared with respect to continuous outcome variables such as increase in blood pressure 10 minutes after ITD placement, time to measurable blood pressure or a 10 mmHg increase in blood pressure, by t-tests and by chi-square tests. Examination of the distribution of the variables will determine whether transformations are needed or non-parametric tests are preferable (Wilcoxon rank sum test instead of t-test, Friedman's rank test instead of repeated measures ANOVA). Descriptive statistics will be obtained for all variables. Results will consist of means ± 1 standard error and percentages. Data will be stratified based upon study site in some analyses.

CRITERIA FOR INCLUSION OF SUBJECTS:
Subjects that present to the emergency medicine department with systolic blood pressures < 95 mm Hg will be considered for study enrollment. A researcher will explain the nature of the study to the subject and obtain informed consent per federal regulations and Institutional Review Board governance. Once it has been determined that the subjects meet enrollment criteria based upon the inclusion and exclusion criteria, and informed consent is obtained, subjects will be randomized to either a sham ITD or an active (functional) ITD.
Patient inclusion and exclusion criteria:
Inclusion criteria:
Age 18-70,
Conscious patient,
Systolic BP < 95 mmHg upon initial ER reading,
Cause of hypotension: a) blood loss, or b) dehydration
CRITERIA FOR EXCLUSION OF SUBJECTS:
Exclusion criteria:
Age <18, >70
Hypotension secondary to heart failure
Unconscious or barely conscious
Complaints of chest pain (currently contraindication for use per FDA approved labeling)
History of heart failure (currently contraindication for use per FDA approved labeling)
Complaints of shortness of breath (currently contraindication for use per FDA approved labeling)
History of pulmonary hypertension
There are no restrictions on prior or concomitant therapy

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