Light Therapy in Cardiopulmonary Bypass Surgery

The goal of this study is to determine whether or not exposure to blue spectrum light reduces acute kidney injury and systemic inflammation in subjects undergoing cardiopulmonary bypass. Subjects scheduled to undergo cardiopulmonary bypass surgery will be exposed to either bright (1000 lux) blue spectrum (480nm) light or to ambient, white fluorescent light for a 24 hour photoperiod the day prior to surgery and for a 24 hour photoperiod in the immediate postoperative period.

Light modifies the biology and physiology of mammals, including humans. The cellular biology of both the immune system, as well as, the cells comprising tissues and organs (e.g., kidney, liver) are under the regulation of light and exhibit circadian rhythms. Studies show that the severity of organ injury varies with the time of the day, the duration of the day, and the season. This variation is due to the biology of circadian rhythms, and light is the principle environmental cue entraining circadian biology. More recent data suggest that modulating the spectrum of light to which an organism is exposed may therapeutically modulate the cellular response to stress or injury. Specifically, exposure to a short (24 hour) photoperiod of high illuminance, blue spectrum light attenuated liver and kidney injury when animals were subjected to ischemia/reperfusion (I/R), a model in which the blood flow to an organ is temporarily reduced and then restored. A predominant cause of organ injury in this model is the misdirected and exacerbated inflammation of a type of immune cell called the neutrophil. However, blue light inhibited neutrophil infiltration into the ischemic kidney and liver, and thereby reduced inflammation and neutrophil-mediated organ injury. Cardiopulmonary bypass (CPB) surgery is an operation characterized by excessive inflammation and a high risk of organ injury, particularly acute kidney injury (AKI). Thus, we hypothesize that exposure to blue light, by comparison to standard environmental, white fluorescent light, will reduce inflammation, organ injury and improve the outcome of patients undergoing CPB.

Exposure to high illuminance (1000 lux), blue spectrum (480nm) light for the 24 hour photoperiod prior to surgery and for the 24 hour photoperiod immediately after surgery

Exposure to high illuminance (1000 lux), blue spectrum (480 nm) light for a 24-hour photoperiod immediately before surgery and a 24-hour photoperiod immediately after surgery

Change in serum creatinine concentration at 24 hours after surgery compared to preoperative baseline creatinine concentration

Change in serum BUN concentration at 24 hours after surgery compared to preoperative baseline BUN concentration

Change in serum cytokine concentrations comparing serum concentrations at 24 hours after surgery to serum concentrations immediately (with 1 hour) after surgery

Inclusion Criteria: age greater than or equal to 18 years undergoing cardiopulmonary bypass surgery Exclusion Criteria: Blindness Immunocompromised or immunosuppressed state Anticipated survival < 24 hours

Yuan D, Collage RD, Huang H, Zhang X, Kautza BC, Lewis AJ, Zuckerbraun BS, Tsung A, Angus DC, Rosengart MR. Blue light reduces organ injury from ischemia and reperfusion. Proc Natl Acad Sci U S A. 2016 May 10;113(19):5239-44. doi: 10.1073/pnas.1515296113. Epub 2016 Apr 25.

Castro RA, Angus DC, Hong SY, Lee C, Weissfeld LA, Clermont G, Rosengart MR. Light and the outcome of the critically ill: an observational cohort study. Crit Care. 2012 Jul 24;16(4):R132. doi: 10.1186/cc11437.