The Purpose of the study is to test the hypothesis that administration of an S-nitrosylating (SNO) agent can improve tissue oxygenation during transfusion of packed red blood cells (RBCs).
Transfusion is the most common therapeutic intervention employed to maintain and/or improve tissue and end-organ oxygen delivery. Despite the conceptual simplicity of this treatment recent studies indicate that RBC infusion often produces little clinical benefit and may actually harm the recipient by exacerbating rather than correcting anemia-induced tissue hypoxia. The main driver/regulator of tissue oxygenation is blood flow not blood oxygen content. In turn flow into the microvasculature is controlled by small molecules called S-nitrosothiols (SNOs), the most important of which is S-nitrosylated hemoglobin (SNO-Hb). The investigators determined that storage of human blood leads to rapid losses in SNO-Hb that are precisely paralleled by losses in the ability of stored RBCs to dilate blood vessels and thereby deliver oxygen. The investigators have now recently completed an autologous human blood transfusion that confirms the pre-clinical findings in that administration of 1 unit of packed RBCs to young healthy subjects did not improve tissue oxygenation and reduced circulating SNO-Hb levels. This novel mechanism for the loss of physiological activity in banked blood and, more importantly, a putative intervention for its correction, raise the possibility that restoration of NO bioactivity could correct the deficit in oxygen delivery. As such, The Investigators plan to repeat our transfusion study with the addition of administering an S-nitrosylating agent during RBC infusion.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
35
S-nitrosylating agent (SNO) Inhalation
Normal Saline transfusion
Blood transfusion (RBCs)
University Hospitals Cleveland Medical Center
Cleveland, Ohio, United States
RECRUITINGPeripheral Tissue Oxygenation
Measurement of small vessel blood flow and oxygenation status with near infrared spectroscopy (NIRS). NIRS can record the amount of oxygenated and de-oxygenated hemoglobin (the main protein in red blood cells) using different light frequencies shined through probes attached to the skin. The tissue oxygenation measurement is expressed as a percentage based on the ratio of oxygenated to de-oxygenated hemoglobin. It is continually-measured to see if it is changing in response to transfusion or administration of the study drug.
Time frame: Monitoring is continuous once the probes are placed on the skin. It will start approximately 30 minutes prior to blood transfsuion and continue overnight and then stopped next morning when subject is discharged. Total time is up to 24 hours.
Oxygen Utilization
Determined by measuring arterial and venous blood oxygen levels - Blood Gas (BG) A BG is a test that measures the the levels of oxygen (O2) in the blood obtained from an artery or vein. The test is used to check the function of the patient's lungs and how well they are able to move oxygen around the body. The amount of oxygen is expressed as percent of the overall amount of hemoglobin. The difference in the amount of oxygen in arterial and venous blood is calculated as the measure of oxygen utilization and if it is changing in response to transfusion or administration of the study drug.
Time frame: Blood samples are obtained every 3 to 6 hours before during and after blood transfsuion until subject is discharged Total time is up to 24 hour
Kidney Function Test
Blood samples will be assayed for markers of kidney function: creatinine - milligram per deciliter albumin - grams per deciliter blood urea nitrogen - milligram per deciliter This 3 blood markers are incorporated into a formula to calculate glomerular filtration rate or GFR. This is a measure of how well your kidneys are filtering your blood and if it is changing in response to transfusion or administration of the study drug.
Time frame: Blood samples are obtained every 3 to 6 hours before during and after blood transfsuion until subject is discharged Total time is up to 24 hour
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Liver Function Test
Blood samples will be assayed for markers of liver function: alanine transaminase or ALT - units per liter aspartate aminotransferase or AST - units per liter The individual values are determined then the AST/ALT ratio is calculated to provide further information on liver status and if it is changing in response to transfusion or administration of the study drug.
Time frame: Blood samples are obtained every 3 to 6 hours before during and after blood transfsuion until subject is discharged Total time is up to 24 hour
Assessment of Immune Status
The number of white blood cells is counted in each blood sample. White blood cells (also called leukocytes) are an important measure of how the immune system is working and if it is changing in response to transfusion or administration of the study drug. leukocytes - reported as cell counts
Time frame: Blood samples are obtained every 3 to 6 hours before during and after blood transfsuion until subject is discharged Total time is up to 24 hour