A low-cost method for measuring the temperature of IV fluids through IV tubing or IV bags would be a game changer for the safety of the OpenFluidWarmer design. I have purchased three GY-906 BAA IR temperature sensors this week for testing. I am encouraged by medical temperature measurement studies that have shown that non-contact IR temperature sensors can achieve +/- 0.5°C measurement accuracy. 

Temperature sense of the IV fluid at the IV bag will ensure that the operator has a double check on inlet IV fluid temperature. Inlet temperature determines the length of IV tubing that is to be immersed in the water bath, water bath set point temperature, and IV fluid flow rate. 

Temperature sense of the IV fluid in the IV tube at the outlet of the OpenFluidWarmer will ensure that IV fluid is not warmed above the threshold at which hemolysis begins to occur. Warming the fluid above temperature can be caused by immersing too much length of IV tubing in the temperature bath, using too high of a water bath setpoint temperature, assuming too high of an inlet IV fluid temperature, or using too low of a IV fluid flow rate.

Without IV fluid temperature measurement at the inlet and outlet, the burden is on operator to ensure that the IV fluid remains within the normal operating temperature limits. Incorporating IV fluid temperature sense can help reduce the burden on the operator and help quickly identify over temperature hazardous conditions. 

I remain skeptical that there might be an accurate, low-cost method to measure IV fluid temperatures through IV tubing and IV bags, but am confident that there is something to be learned from testing these GY-906 BAA IR temperature sensors.