Fifty percent of children that survive a critical illness are anemic at discharge from the pediatric intensive care unit (PICU)(1). Given that there are approximately 9000 PICU admissions/year in Canada, this represents almost 4500 children per year. Anemia is associated with abnormal neurocognitive development in infants and young children. A contributor to PICU anemia is the excessive amount of blood testing and iatrogenic blood losses(2). Non-invasive continuous hemoglobin monitoring (Sp-Hb) have been developed in the medical setting in an attempt to minimize invasive blood testing and reduce blood losses. The Radical 7 Masimo device (Masimo corporation, Irvine, CA) is one of the popular devices used for non-invasive hemoglobin monitoring. Its accuracy has been previously investigated in various populations(3-6). The objective of this study is to investigate the validity of the Radical 7 Masimo device at measuring hemoglobin trends non-invasively in critically ill children.

This will be a prospective observational study. We will include 1) all patients that are admitted to the PICU of the CHUSJ after a cardiac surgery, 2) that are aged less than 6 months on the day of admission and that 3) have an arterial line inserted.

All children studied will have an arterial line inserted at the time of surgery that will allow for arterial-Hb measurements. As this study is strictly observational, all arterial-Hb measurements will be requested by the medical treating team as clinically indicated. We will install, on admission, the spectrophotometric adhesive sensor required for Sp-Hb measurements on each patient (Masimo Rainbow R1 20 for children over 30 kg and R1 20L for those under 30 kg). The sensor will be applied on the hand or foot that does not have an arterial cannula. The sensor will be covered with an impermeable black shield to prevent optical interference.

We will collect all the arterial-Hb measurements performed in the 48 hours after PICU admission as well as all the Sp-Hb readings performed at the time of the arterial samples. The blood samples drawn from the arterial catheter will be analyzed using a laboratory CO-oximeter (model ABL820; Radiometer, Copenhagen, Denmark). Simultaneous recording of Sp-Hb will performed within 10 seconds after the arterial blood sample is drawn. We will also collect demographic data and clinical data on each patient; age, weight, sex, ethnicity, type of cardiac surgery, blood transfusions. At the CHUSJ PICU, all clinical and demographic data is systematically recorded in our electronic database (Intellispace Critical Care and Anesthesia, Philips Medical Systems). Data on red cell transfusions are recorded through the TracelineTM database that is made available to our research group through Héma-Québec. Data will be extracted from our database by our research assistant.

Inclusion Criteria:

• 1) patients that are admitted to the PICU of the CHUSJ after a cardiac surgery, 2) that are aged less than 6 months on the day of admission and that 3) have an arterial line inserted.

Children admitted to the PICU after a cardiac surgery