Purpose;

The study quantified functional measures of red blood cell mass and oxygen in neonatal tissues using a non-invasive optical technique: near infrared optical spectroscopy (NIRS). The study is determined the absolute concentrations of deoxygenated and oxygenated hemoglobin and calculate the tissue hemoglobin saturation and total hemoglobin concentration in vivo. NIRS technique use to assessing and defining tissue status in the anemic state and the tissue's response to transfusions, as well as in monitoring hemoglobin and hematocrit without pain or loss of blood.

Hypothesis;

NIRS measurements of hemoglobin and hemoglobin saturation in tissues before and after red-cell transfusions in VLBW infants will determine the true effect of the transfusions, and develop more substantial guidelines regarding indications for transfusion. The accuracy of conventional (invasive) measurements of Hb and Hct could be comparison with results from the NIRS technique and clinical usefulness of the NIRS technique could be evaluated by comparison with trends in conventionally measured values taking fluid status into account.

The red to near-infrared part of the electromagnetic spectrum (600 to 1000 nm) allows photons to penetrate a few centimeters below the surface of the skin. These photons are non-ionizing and do not induce local heating. Quantitative optical spectroscopy in the 600-1000 nm region thus allows safe, non-invasive measurements of the concentrations of blood, water, and lipids in tissues. NIRS spectroscopy has been in use for clinical studies (UCI HS#1995-563 HS#2002-2306). These studies have shown clearly the enormous sensitivity of quantitative NIRS spectroscopy to hemodynamic events in tissues.

Procedure;

NIRS measurements will be conducted on the muscle, on the upper leg,arm or on the back, abdomen and the head. The actual location will depend upon the neonate position and size. A small soft plastic optical fibers probe will be place to the select study areas and thhe time of the measurement will not exceed 1 hour.

Anticipate risk and benefit;

Near-infrared light does not ionize biological tissue and poses no significant health risk. Since water absorption is low within this spectral range, local heating of the tissue is also minimal. Burns and heat damage to the neonate are highly unlikely.

There are no known direct therapeutic benefits of this procedure.

Inclusion Criteria:

• infants weighing less than 1500 grams at birth
• infants receiving at least one packed red blood cell transfusion

Exclusion Criteria:

• neonates who are too unstable as determined by the clinicians for additional human contact