Peter H. Breen

picture of Peter H. Breen

Associate Professor, Anesthesiology
School of Medicine

M.D., University of Manitoba, Canada, 1977
F.R.C.P.C (1986); A.B.A. (1986)

Phone: (714) 456-2818

University of California, Irvine
Dept. Anesthesiology, UCI Medical Center
Rm 227, Bldg 53, Rt 81A, 101 The City Drive
Mail Code: 1350
Orange, CA 92868
Research Interests
Gas Kinetics in Anesthesia during Non-Steady State; humidity sensor; carbon monoxide; cyanide; numerical analysis gas exchange modeling; anesthesia virtual reality simulation
Academic Distinctions
1999-2003 Invited member of Subcommittee on Equipment, Monitoring, and Engineering Technology (American Society of Anesthesiologists)
Research Abstract
Dr. Breen conducts research in the field of gas kinetics in anesthesia during non-steady state. For example, he has shown that proportional decreases in exhaled CO2 concentration and volume can be a marker of and measure decreases in cardiac output. These projects are conducted in experimental models, bench preparations, mathematical and computer models and clinical studies. These studies in gas exchange pathophysiology have direct importance to patients as clinical monitoring tools, during anesthesia and critical care medicine. The technology being developed for these research studies have crossover into both biomedical and engineering and computer science. In particular, Dr. Breen has invented and patented a fast response humidity sensor and an in-line mixing chamber (bymixer).

A second general research area is the study of the pathophysiology and optimal treatment of combined carbon monoxide and cyanide poisoning, which occurs during fire and smoke exposure. Dr. Breen's group has shown that the most important early maneuver in the cyanide component of the poisoning is cessation of toxic exposure, due to the initial, rapid and spontaneous metabolic and cardiovascular recovery. Further, they have identified a potential place for stroma-free methemoglobin during prolonged cyanide toxicity. Other research interests include studies of respiratory mechanics and monitoring during anesthesia (such as detection of bronchial flap-valve obstruction by exhaled flow monitoring) and refinements in the use of the laryngeal mask airway during anesthesia.

Dr. Breen's research interests also include the development of a numerical analysis virtual reality anesthesia simulator.


Fast response airway humidity sensor for patients

Bymixer Apparatus and Method for Fast-Response, Adjustable Measurement of Mixed Gas Fractions in Ventilation Circuits
Available Technologies
BREEN PH. Bymixer Apparatus and Method for Fast-Response Adjustable Measurement of Mixed Gas Fractions in Ventilation Circuits. U.S. Continuation in Part patent application (USPTO Serial No. 12/874,630). Filing Date: September 2, 2010
BREEN PH. How do changes in exhaled CO2 measure changes in cardiac output? A numerical analysis model. Journal of Clinical Monitoring and Computing, 2010 24: 413-419.
BREEN PH. Bymixer apparatus and method for fast-response, adjustable measurement of mixed gas fractions in ventilation circuits. United States Patent, Sept. 14, 2010; Number 7,793,659: 17 pages.
Rosenbaum A, Howard HC, Breen PH. Novel portable device measures preoperative patient metabolic gas exchange. Anesthesia & Analgesia, 2008; 106: 509-516.
Rosenbaum A, Kirby CW, BREEN PH. Bymixer system can measure O2 uptake and CO2 elimination in the anesthesia circle circuit. Canadian Journal of Anesthesia 2007; 54: 430-440.
Rosenbaum A, BREEN PH. Importance and interpretation of fast-response airway hygrometry during ventilation of anesthetized patients. Journal of Clinical Monitoring and Computing, 2007; 21: 137-146.
Rosenbaum A, Kirby C, BREEN PH. New metabolic lung simulator: development, description, and validation. Journal of Clinical Monitoring and Computing; 2007; 21: 71-82.
Rosenbaum A, Kirby C, BREEN PH. Measurement of oxygen uptake and carbon dioxide elimination utilizing the bymixer: validation in a metabolic lung simulator. Anesthesiology 2004; 100: 1427-1437.
Rosenbaum A, BREEN PH. Novel, adjustable, clinical bymixer measures mixed expired gas concentration in anesthesia circle circuit. Anesthesia & Analgesia, 2003; 97: 1414-1420
BREEN PH. Arterial Blood Gas and pH Analysis: Clinical Approach and Interpretation IN Monitoring During Critical Events; Editor, WC Wilson; Anesthesiology Clinics of North America, WB Saunders, Philadelphia; 2001; 19: 885-906
BREEN PH. Importance of temperature and humidity in the measurement of pulmonary oxygen uptake per breath during anesthesia. Annals of Biomedical Engineering 2000; 28: 1159-1164
Johnson JL, BREEN PH. How does positive end-expiratory pressure decrease pulmonary CO2 elimination in anesthetized patients? Respiration Physiology 1999; 118: 227-236
BREEN PH, Jacobsen BP. Carbon dioxide spirogram (but not capnogram) detects leaking inspiratory valve in circle circuit. Anesthesia & Analgesia 1997; 85: 1372-1376
BREEN PH, Serina ER, Barker SJ. Exhaled flow monitoring can detect bronchial flap-valve obstruction in a mechanical lung model. Anesthesia & Analgesia 1995; 81:292 296
BREEN PH, Isserles SA, Westley J, Roizen MF, Taitelman UZ. Combined carbon monoxide and cyanide poisoning: A place for treatment? Anesthesia & Analgesia 1995; 80:671 677
BREEN PH, Isserles SA. Right atrial bypass model in the dog. American Journal of Veterinary Research 1995; 56:208 214
BREEN PH, Isserles SA, Harrison BA, Roizen MF. Simple, computer measurement of pulmonary VCO2 per breath. Journal of Applied Physiology 1992; 72:2029 35
Isserles SA, BREEN PH. Can changes in end-tidal PCO2 measure changes in cardiac output? Anesthesia & Analgesia 1991; 73:808 14
NIH R01 HL-42637
Professional Societies
American Society of Anesthesiologists
Association of University Anesthesiologists (elected)
International Anesthesia Research Society
Research Center
General Clinical Research Center, UCIMC
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