March 5th, 2015
Has Lab Testing Become a Blood Sport for Cardiac Surgery Patients?
The CardioExchange Editors interview Colleen G. Koch, lead author of a study of the extent of blood testing in cardiac surgery patients at Cleveland Clinic. The article is published in the Annals of Thoracic Surgery and was covered in a recent CardioExchange news story.
For 1894 patients who underwent cardiac surgery at the Cleveland Clinic from January through June of 2012, there were 221,498 laboratory tests. Of those tests (mean, 115 per patient), 40% measured arterial or venous blood-gas levels, 18% assessed blood coagulation, 14% were for a complete blood count, 13% were for metabolic panels, and 5% were for blood cultures. The cumulative median volume of drawn blood during a hospital stay was 454 mL per patient.
CardioExchange Editors: Any reason to think Cleveland Clinic is better or worse than most hospitals when it comes to testing cardiac surgery patients’ blood?
Koch: Hospital systems vary according to whether they have primarily surgical or medical hospitalizations, the proportion of critically ill patients who require an ICU stay, and patient complexity. Any hospital with a similar ratio of surgical-to-medical hospitalizations and a similar patient acuity (i.e., degree of patient sickness) is likely to have findings similar to ours. If phlebotomy volumes are in excess, the patient is more likely to develop anemia.
Interestingly, in a separate recent investigation, our group studied the percentage of patients who came into the hospital with a normal hemoglobin value (not anemic) and followed their hemoglobin levels throughout hospitalization until hospital discharge to see whether they developed anemia. Among roughly 188,000 patients with medical or surgical hospitalizations in the Cleveland Clinic Health System, more than 70% developed anemia in the hospital. We found that patients who developed hospital-acquired anemia had worse outcomes (Koch et al. J Hosp Med 2013; 8:506). Other investigations report the association between higher phlebotomy volume and development of hospital-acquired anemia, so in the current study we sought to determine the amount of blood drawn for laboratory testing (phlebotomy volume) in the patients we cared for who were undergoing heart surgery.
Editors: You suggest that patients ask questions about the necessity of tests. Is this practical in most cases?
Koch: Yes, patients should be empowered to become more involved in their care and ask questions. Specifically, they should ask whether a test is necessary, should it be done every day, and or can smaller-volume test tubes be used? Cleveland Clinic has become a role model as an organization that embodies “patient-centered care.”
Editors: What can be done to change this culture?
Koch: Change begins with caregivers becoming aware of how their practices and processes influence patient outcomes. Second, you cannot manage what you do not measure. If caregivers were more aware of the total amount of blood taken throughout the care continuum, and how development of anemia relates to patient outcome and resource utilization, they might change how they practice.
Editors: Should this be assessed during hospital certifications?
Koch: Interestingly, 20 years ago, development of infections during the course of hospitalization was an event that occurred not infrequently. With increased measurement and emphasis on the morbidity implications of hospital-acquired infections, this outcome is a current metric for in-hospital quality of care.
I can only imagine that hospital-acquired anemia, which has many contributing factors (excess phlebotomy volume among them), may be on the radar as a possible quality metric, similar to hospital-acquired infections. Hospital-acquired anemia increases hospital resource utilization (total charges, length of stay) and, more important, is associated with greater patient mortality. Our current paper reports an association between increased red-blood-cell transfusion and excess phlebotomy volume. Of note, RBC transfusions are also expensive and have associated morbidity and mortality complications.
JOIN THE DISCUSSION
Are Dr. Koch’s findings likely to affect how your institution approaches blood testing in cardiac surgery patients?