This will be an observational study. The continuous hemoglobin monitor will be connected to the patient and hemoglobin measurement data will be collected. Routine laboratory hemoglobin monitoring will occur concurrently at a pre-specified frequency as well as at the physician's discretion based on usual clinical information. The physician will be blinded to the continuous hemoglobin monitoring readings and therefore patient care will not be affected by the use of the monitor. Once the study has ended, the data will then be analyzed to assess for correlation between continuous hemoglobin monitoring readings and laboratory hemoglobin measurement.