title: Speed of blood withdrawal and accurate measurement of oxygen content in mixed venous blood.
abstract: BACKGROUND
  Measurement of mixed venous oxygen saturation helps determine whether cardiac output and oxygen delivery are sufficient for metabolic needs. As recommended by the American Association of Critical-Care Nurses guideline, blood samples for determining mixed venous oxygen saturation are obtained by slowly, in 1 to 2 minutes, withdrawing 1.5 mL of blood from the distal port of the pulmonary artery catheter. In theory, the negative force of rapid withdrawal could pull oxygenated blood from the pulmonary capillary bed, causing falsely elevated saturation values.
  
  
  OBJECTIVE
  To determine if the speed of withdrawal affects oxygen content in blood samples used to measure mixed venous oxygen saturation.
  
  
  METHODS
  The sample consisted of heart failure patients with pulmonary artery catheters admitted to a cardiac intensive care unit. A prospective, randomized, 2 × 2 crossover design was used to compare mixed venous oxygen saturation in blood samples obtained quickly or slowly. A total of 50 sets of saturation values were analyzed. Each set included 1 blood sample obtained slowly, in 1 to 2 minutes, and 1 obtained rapidly, in 5 seconds.
  
  
  RESULTS
  The mean difference in saturation values between the fast and the slow groups was -0.3 (CI, -1.5 to 0.8; P = .55), indicating that no meaningful systematic bias is attributable to fast withdrawal of blood.
  
  
  CONCLUSIONS
  Rapid blood sampling does not falsely elevate measurements of mixed venous oxygen saturation.
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Katie
authors.initials: K
authors.lastname: Jaschke
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Dianna
authors.initials: D
authors.lastname: Brown
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Alicia
authors.initials: A
authors.lastname: Clark
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Sarah
authors.initials: S
authors.lastname: Doull
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Ashley
authors.initials: A
authors.lastname: English
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Nicole
authors.initials: N
authors.lastname: Hoover
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Philip
authors.initials: P
authors.lastname: Jones
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: David
authors.initials: D
authors.lastname: Klamm
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Chung
authors.initials: C
authors.lastname: Odom
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Brenna
authors.initials: B
authors.lastname: Primrose
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System.
authors.forename: Kristin
authors.initials: K
authors.lastname: Sollars
authors.affiliation: Katie Jaschke, Dianna Brown, Alicia Clark, Sarah Doull, Nicole Hoover, and David Klamm are staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City, Kansas City, Missouri. Ashley English, Chung Odom, Brenna Primrose, and Kristin Sollars were staff nurses in the cardiac intensive care unit at Saint Luke's Hospital of Kansas City when the study was done. English is now a nurse practitioner for the Saint Luke's internal medicine group in Kansas City, Missouri. Odom is now a staff nurse in the surgical trauma intensive care unit at University of Arkansas Medical Center in Little Rock. Primrose is now an acute care nurse practitioner in the neurosurgical intensive care unit at Saint Luke's Hospital. Sollars is now a clinical education specialist in critical care for Saint Luke's Health System, Kansas City, Missouri. Philip Jones is a senior biostatistician for the cardiovascular outcomes group, Mid-America Heart Institute, Kansas City, Missouri. Marci Ebberts is a clinical education specialist for Saint Luke's Health System. mebberts@saint-lukes.org.
authors.forename: Marci
authors.initials: M
authors.lastname: Ebberts
mesh_terms: D001784:Blood Gas Analysis; D002302:Cardiac Output; D002407:Catheterization, Swan-Ganz / Q000379:methods; D064648:Critical Care Nursing / Q000379:methods*; D018592:Cross-Over Studies; D005260:Female; D006333:Heart Failure / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000097:blood*; D018962:Phlebotomy / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D010100:Oxygen