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Kirk Shelley, MD/PhD

Professor Emeritus of Anesthesiology

Research Summary

Dr. Kirk Shelley has extensive experience in pulse oximeter waveform research and the development of patient monitoring devices.

As an ambulatory anesthesiologist, Dr. Shelley is committed to the development of the best possible noninvasive monitoring technology. Dr. Shelley's focus has been on the photoplethysmographic waveform (PPG). His primary goal has been to understand the physiology that creates the PPG with an emphasis on its venous and respiratory components. His secondary goal is the utilization of this understanding to develop new methods of patient monitoring. Dr. Shelley believes that the state-of-the-art digital signal processing methods combined with new understandings of cardiovascular physiology will allow for significant breakthroughs in this field.

Specialized Terms: Pulse oximeter waveform analysis; Photoplethysmography; Ambulatory Care; Anesthesiology; Biochemistry; Cardiovascular Diseases; Electrical Engineering Or Electronics; Internal Medicine; Medical Devices; Surgery; Medical Devices; Non-invasive Cardiovascular Monitoring; Patient Monitoring; Pulse Oximeter Research

Extensive Research Description

The main thrust of my work has involved pulse oximetry technology. The pulse oximeter is the most commonly used clinical monitor in the healthcare system.  The photoplethysmographic (PPG) waveform is at the core of pulse oximeter technology. I have worked to expand the understanding and use of this noninvasive cardiopulmonary waveform.  Some of my most cited papers are educational and provocative in nature.  They challenge the reader to re-examine this ubiquitous wave for features beyond its primary use of oxygen saturation measurement.  These papers point out that the PPG contains information regarding the cardiovascular, pulmonary and autonomic systems. [1-4]

1.      Shelley, K.H., Photoplethysmography: Beyond The Calculation Of Arterial Oxygen Saturation And Heart Rate. Anesth Analg, 2007. 105(6 Suppl): p. S31-6.

2.         Shelley, K.H. and S. Shelley, Pulse Oximeter Waveform: Photoelectric Plethysmography, in Clinical Monitoring: Practical Applications for Anesthesia and Critical Care, C.L. Lake, R.L. Hines, and C.D. Blitt, Editors. 2001, W.B. Saunders Company: Philadelphia PA. p. 420-428.

3.         Alian, A.A. and K.H. Shelley, Photoplethysmography. Best Pract Res Clin Anaesthesiol, 2014. 28(4): p. 395-406.

4.         Alian, A.A. and K.H. Shelley, Photoplethysmography: Analysis of the pulse oximeter waveform, in Monitoring Technologies In Acute Care Environments, J.M. Ehrenfeld and M. Cannesson, Editors. 2014, Springer New York. p. 165-178.

In the process of studying the pulse oximeter waveform (PPG) I have discovered a number of unanticipated features.  These have included the impact of peripheral venous blood on the waveform. This has allowed for the explanation of device artifact as well the calculation of new clinical parameters.  Most notably, this research is the key component of a new monitoring technique that my laboratory developed for the detection of blood loss during pediatric cases. (1-4)

1.         Shelley KH, Dickstein M, Shulman SM. The detection of peripheral venous pulsation using the pulse oximeter as a plethysmograph. J Clin Monit 1993;9:283-7.

2.         Shelley K, Tamai D, Jablonka D, Gesquiere M, Stout R, Silverman D. The effect of venous pulsation on the forehead pulse oximeter wave form as a possible source of error in SPo2 calculation. Anesth Analg 2005;100:743-7.

3.         Walton ZD, Kyriacou PA, Silverman DG, Shelley KH. Measuring venous oxygenation using the photoplethysmograph waveform. J Clin Monit Comput 2010;24:295-303.

4.         Alian AA, Atteya G, Gaal D, Golembeski T, Smith BG, Dai F, Silverman DG, Shelley K. Ventilation-Induced Modulation of Pulse Oximeter Waveforms: A Method for the Assessment of Early Changes in Intravascular Volume During Spinal Fusion Surgery in Pediatric Patients. Anesth Analg 2016;123:346-56.

The photoplethysmographic (PPG) waveform is created by the interaction of the cardiac, pulmonary and autonomic systems.  By studying this interaction, one can gain clues as to a patient’s condition as well as ways of optimizing it via therapeutic interventions. One of the earliest observations was the impact of ventilation on the PPG waveform.  Through my research, it was discovered that both cardiac output (stroke volume) and pre-load (venous) blood are modulated.  These modulations can be identified and quantified.  Through optimization of these parameters it was found that they could be used to guide IV fluid therapy during hypovolemia. (1-4)

1.         Shelley KH, Awad AA, Stout RG, Silverman DG. The use of joint time frequency analysis to quantify the effect of ventilation on the pulse oximeter waveform. J Clin Monit Comput 2006;20:81-7.

2.         Shelley KH, Jablonka DH, Awad AA, Stout RG, Rezkanna H, Silverman DG. What is the best site for measuring the effect of ventilation on the pulse oximeter waveform? Anesth Analg 2006;103:372-7.

3.         Alian AA, Galante NJ, Stachenfeld NS, Silverman DG, Shelley KH. Impact of central hypovolemia on photoplethysmographic waveform parameters in healthy volunteers part 2: frequency domain analysis. J Clin Monit Comput 2011;25:387-96.

4.         Scully CG, Selvaraj N, Romberg FW, Wardhan R, Ryan J, Florian JP, Silverman DG, Shelley KH, Chon KH. Using time-frequency analysis of the photoplethysmographic waveform to detect the withdrawal of 900 mL of blood. Anesth Analg 2012;115:74-81.



Research Interests

Ambulatory Care; Anesthesiology; Biochemistry; Cardiovascular Diseases; Cardiovascular Physiological Phenomena; Electronics, Medical; Plethysmography; Monitoring, Intraoperative

Research Images

Selected Publications