Improving the Patient Experience with Indocyanine Green Lymphography

Since 2007, when indocyanine green lymphography was first introduced as a method of visualizing the superficial lymphatic system,1 this imaging study has become instrumental in lymphatic care.2 Indocyanine green lymphography is routinely performed in the outpatient clinic setting, but intense pain from its pH at the injection site remains a significant hurdle in the patient experience. Developing a relatively painless method of performing indocyanine green lymphography is important for patients to readily accept this imaging modality and for clinicians to be willing to perform it routinely. Our team set out to test previously recommended formulations of the indocyanine green dye to determine the optimal technique for our patients. One previously proposed idea for reducing the pain at indocyanine green injection sites was to mix the indocyanine green dye with an anesthetic agent (e.g., xylocaine 1%).3 A concern of this approach is the depressing effect lidocaine can have on lymphatic contractility.4 A more recent proposal was to utilize a cryogenic numbing device Cool Sense (CoolSense, Tel Aviv, Israel) to temporarily numb the site before injection.5 A third technique was discovered by our team while visiting Dr. Takumi Yamamato in 2018. We witnessed his team inject patients utilizing a formulation of indocyanine green with 5% dextrose solution with seemingly little patient discomfort. Given the importance of clarifying the most comfortable technique for patients, we tested the different formulations and techniques on ourselves. Specifically, we tested three formulations (indocyanine green with sterile water, indocyanine green with 1% lidocaine, and indocyanine green with 5% dextrose) and two techniques (Cool Sense versus no Cool Sense). All indocyanine green lymphography at our center is performed by a lymphatic surgeon (D.S.) or lymphatic surgery nurse practitioner (E.T.). Therefore, each individual injected the other at eight sites on the bilateral upper extremities with various formulations. Of note, the individual being injected was blinded to the formulation at each site. Although we also studied the potential role of Cool Sense at half the sites, the individual could not be blinded to this intervention. Our findings were consistent between the two individuals being injected. Specifically, the most painful injection occurred with indocyanine green and sterile water solution plus cryotherapy, with a visual analogue scale score 6 to 8. The least painful was found to be indocyanine green and 5% dextrose solution without cryotherapy, with a visual analogue scale score 0 to 1. Of note, regardless of formulation or use of the cryogenic device, excellent mapping of the lymphatic system was achieved from all injection sites (Fig. 1).Fig. 1.: Representative images of right upper extremity indocyanine green lymphography for volunteers E.T. (above) and D.S. (below). White arrows point to the ulnar injection site, and the arrows with an asterisk point to the radial injection. Regardless of the dye formulation used or the application of cryotherapy, adequate and equivalent visualization of the lymphatic channels was achieved.Today, we mix the stock 25 mg per vial indocyanine green powder (Diagnostic Green, Aschheim-Dornach, Germany) with 9.5 cc of 5% dextrose solution (Baxter, Deerfield, Ill.) and 0.5 cc of 5% albumin (Baxalta, Bannockburn, Ill.). We inject 0.1 cc of this modified indocyanine green solution intradermally with a 30-gauge needle. Over the past year, we have noted a significant drop in patient discomfort from this change in technique and wanted to share this experience. Optimizing the patient experience by reducing pain will ensure the best possible patient care and continued progress in the exciting field of lymphatic surgery. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article. No funding was received for this study.