Preliminary Data: Episodic hemoglobin sampling during transplantation in 13 pediatric patients at NMC revealed the following: anemic values occurred in 69% (9/13) of the patients, with 38% (5/13) of those having 3 or more anemic values (lowest hgb: 1.7g/dL); polycythemic values occurred in 13% (2/13) of the patients (highest hgb: 14.8g/ dL). All patients displayed hypotension during the operative period despite having CVP measurements that matched pre-transplant values. During a recent introductory session for the Masimo Rainbow SET monitor and sensor probe, a toddler undergoing liver, small bowel, and pancreas transplant was observed and hemoglobin values were noted from both the Masimo monitor and conventional episodic blood sampling. Values obtained from both sources simultaneously revealed ≤ 1 g/dL discrepancy between the measurement methods in 100% of the values.