DOI: 10.1111/jocs.13258 NEW TECHNOLOGIES Intraoperative thermographic imaging to assess myocardial distribution of Del Nido cardioplegia Prashant Rao MD, MRCP 1 | Jack B. Keenan MD 2 | Taufiek K. Rajab MD 2 | Alice Ferng PhD 2 | Samuel Kim MD 2 | Zain Khalpey MD, PhD, FETCS 2 1 Sarver Heart Center, University of Arizona, Tucson, Arizona 2 Division of Cardiothoracic Surgery, Department of Surgery, University of Arizona College of Medicine, Tucson, Arizona Correspondence Prashant Rao, Sarver Heart Center, University of Arizona, 1501 N Campbell Ave, Tucson, AZ 85724. Email: prashant.rao@doctors.org.uk Abstract We describe the intraoperative non-invasive use of an infrared (IR) camera to monitor Del Nido cardioplegia delivery in patients undergoing cardiac surgery. Thermal pictures were taken pre- and post-cardioplegia and at timed points after arrest, and compared to readings from a transseptal temperature probe. There was good concordance between the transseptal probe and the IR camera temperature readings. This non-invasive technique, which assesses cardioplegic distribution, may help to determine when additional doses of Del Nido cardioplegia are required during periods of cardioplegic arrest. KEYWORDS cardioplegia, myocardial protection, thermographic imaging 1 | INTRODUCTION Inadequate myocardial protection during cardiopulmonary bypass when the heart is arrested leads to biventricular failure, arrhythmias, and low cardiac output. 1 The most common technique for myocardial protection is intermittent cold cardioplegia. In order for cardioplegia to be effective, it must be distributed to all areas of the heart. Repeated smaller doses of cardioplegia can be given at regular intervals (usually 20-40 min) after the initial arresting dose to maintain hypothermia. However, inadequate delivery of antegrade cardioplegia solution may still occur, particularly in the presence of coronary stenoses and left ventricular hypertrophy. 2 Many surgeons rely on a transseptal needle temperature probe to monitor the temperature of the myocardial septum. Although these readings may accurately assess temperature within the myocardial septum, they may not reflect global myocardial temperatures or provide data regarding temperature heterogeneity. Thermographic imaging potentially overcomes this problem. Intro- duced into cardiac surgery in the 1970s, cardiac thermography is a technique which can detect ischemic areas of the heart. 3 However, it never gained widespread use because older generation thermal cameras were low resolution, bulky, and required an arduous technical set-up. In recent years, there have been several advances in this technology, including the development of smaller camera sizes as well as increased portable usability, resolution, temperature capture, and sensitivity. Current-generation handheld thermal cameras are small enough to sterilely drape and fit into surgical overhead lights. These improvements have made thermographic imaging a viable operating-room technology for monitoring myocardial protection with cold cardioplegia and may help to determine when additional doses of Del Nido cardioplegia are required. 2 | TECHNIQUE Five patients undergoing coronary artery bypass graft (CABG) surgery were randomly selected to undergo thermographic imaging. Approval was obtained from our Institutional Review Board to present these patients. Myocardial protection consisted of moderate hypothermia (32°C), and an initial dose of 1 L of 4°C antegrade Del Nido (DN) cardioplegia solution through the aortic root over a period of approximately 2 min. The heart was completely arrested and cooled with topical ice slush. Additional 500-mL cardioplegia doses at 20-min intervals were infused if global myocardial temperature increased more than 10°C following the initial arresting dose and 50 mL was J Card Surg. 2017;1–4. wileyonlinelibrary.com/journal/jocs © 2017 Wiley Periodicals, Inc. | 1