Study Shows Bedside Blood Testing Lowers Infant Mortality By Up To 74 Percent Following Congenital Heart Surgery

Published on: 07/10/2003
Miami, FL — In hospitals nationwide, three out of four infants who die after undergoing high-risk congenital heart surgery could survive if doctors monitored blood at the bedside and rapidly detected and corrected life-threatening oxygen deficiencies, according to data presented today at the 4th World Congress on Pediatric Intensive Care. The results, reported by Miami Children’s Hospital, were based on survival outcomes in infants whose blood was rapidly tested hourly following surgery, with a point-of-care, hand-held device that tests two drops of blood in two minutes. Compared to national averages, the data showed a 74 percent decline in deaths in babies at highest risk, and a 63 percent drop in deaths overall. 

“The ability to use a tiny blood sample to accurately test lactate levels, a sensitive marker of oxygen debt, in two minutes at the bedside of an infant and then immediately adjust therapy is a major advance in our ability to make life-saving treatment decisions,” said Dr. Anthony Rossi, MD, Director of Cardiac Intensive Care at Miami Children’s Hospital in Miami, FL. “These are definitive and clinically significant findings that, for the first time, show how technological advances in blood testing directly and dramatically improve even the most fragile infant’s chance of survival.” 

The highest risk infants who undergo heart surgery normally have a one in three chance of dying (29.6%) often because post-surgical deficiency of oxygen cannot be diagnosed quickly enough. According to Steven Melnick, MD, Medical Director of pathology at Miami Children’s Hospital, central laboratory samples often take more blood than infants can spare, and time delays are inevitable when transporting specimens to and from the intensive care unit, leading to delays in clinical decision-making. 

“Our ability to bring the lab to the patient gives the lab a much greater role in effecting patient survival,” said Dr. Melnick. “The use of point-of-care testing in infants means that we can test specimens and doctors can react within a five minute window to correct the onset of oxygen deficiency. We know of no other way to test for lactate and adjust therapy all within five minutes. We hope these data will influence care and, ultimately, lower the nation’s rate of infant death, after congenital heart surgery, once more hospitals begin to use the available technology.” 

The Miami Children’s Hospital study used point-of-care testing to monitor oxygen debt by measuring blood lactate for the first 24 hours post-surgery. To determine if treatment should be escalated, diminished or unchanged, i-STATâ System point-of-care testing was used at the bedside every hour for the first four hours after surgery, and then at four to six hour intervals, with immediate therapy changes if necessary. Infant outcomes were then compared pre-and post-use of i-STAT System testing: 
    Infants who underwent heart surgery between July 2001 and April 2003 (n=310) in the i-STAT group were compared to a historical cohort of infants who underwent surgery from June 1995 through June 2001 (n=884). 
    The mean patient weight, age, and risk score for the specific congenital heart surgery performed were not significantly different between the two groups. Total cardiopulmonary bypass time was shorter for the historical group (p=0.001). 
    Overall mortality was found to be 2.6% (=8/310) in the i-STAT group and 7.1% in the historical group (=63/884) (p=0.004). 
    The highest risk infant group showed a reduction in mortality from 29.6% (=21/71) to 7.7% (=2/26). 

A searchable national pediatric database from the Healthcare Cost and Utilization Project (HCUPNet) revealed that there was essentially no change in the overall mortality (7.2 percent to 6.5 percent) or the highest risk group (22.6 percent to 29.5 percent) from 1997 to 2000. These findings from a national database suggest that, the reduction in mortality rate at Miami Children’s Hospital is not explained by changes in pediatric congenital heart surgery practices that may have occurred between 1997 and 2000. 


According to Dr. Rossi, the data have implications for infant care worldwide. “These are the first of several studies we will be releasing,” he added. “We hope Miami Children’s Hospital outcome data will set a standard for other hospitals throughout the country.”

Founded in 1950, Miami Children’s Hospital is the only licensed specialty hospital for children in South Florida. The 268-bed medical complex offers medical care and services for children from birth to age 21.

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