 Randomization process will be carried out based on days of the week. Patients will be enrolled in one group every two days. For example, starting on the week when we begin the trial, we will assign Monday patients to the control group, Tuesday patients to the experimental group, Wednesday patients to the control group... Two groups are similar in characteristics. Depending on whether the subject has been randomized into the control or experimental group, we will not use or use the SpHb monitor to obtain measurements. To obtain measurements, we place the probe of the device on the patients finger and record the hemoglobin level determined by the Masimo Radical-7 Pulse CO-Oximeter. 