TY - JOUR
T1 - The effect of hematocrit during hypothermic cardiopulmonary bypass in infant heart surgery
T2 - Results from the combined Boston hematocrit trials
AU - Wypij, David
AU - Jonas, Richard A.
AU - Bellinger, David C.
AU - Del Nido, Pedro J.
AU - Mayer, John E.
AU - Bacha, Emile A.
AU - Forbess, Joseph M.
AU - Pigula, Frank
AU - Laussen, Peter C.
AU - Newburger, Jane W.
N1 - Funding Information:
Supported by grants HL 063411 and RR 02172 from the National Institutes of Health and by the Farb Family Fund.
PY - 2008/2
Y1 - 2008/2
N2 - Objective: Two randomized trials of hematocrit strategy during hypothermic cardiopulmonary bypass in infant heart surgery have been performed. The first suggested worse outcomes were concentrated in patients with lower hematocrit levels (approximately 20%), whereas the second suggested there was little benefit to increasing the hematocrit level above 25%. The form of the relationship between continuous hematocrit levels and outcomes requires further study. Methods: In the two trials, 271 infants who underwent biventricular repair not involving the aortic arch were enrolled. Analysis was undertaken of the effects of hematocrit level, as a continuous variable, at the onset of low-flow cardiopulmonary bypass. Results: Psychomotor Development Index scores at age 1 year varied nonlinearly with hematocrit levels, with increasing scores up to 23.5% hematocrit (P < .001) and a plateau effect beyond 23.5% (P = .42), based on a piecewise linear model. Lower hematocrit levels were associated with more positive intraoperative fluid balance (P < .001 for linear trend) and marginally associated with higher serum lactate levels at 60 minutes after bypass (P = .08 for linear trend), but not with blood products given, nadir of cardiac index in the first 24 hours, or Mental Development Index scores. Conclusions: A hematocrit level at the onset of low-flow cardiopulmonary bypass of approximately 24% or higher is associated with higher Psychomotor Development Index scores and reduced lactate levels. Because the effects of hemodilution may vary according to diagnosis, age at operation, bypass variables such as pH strategy and flow rate, and other perioperative factors, this study cannot ascertain a universally "safe" hemodilution level.
AB - Objective: Two randomized trials of hematocrit strategy during hypothermic cardiopulmonary bypass in infant heart surgery have been performed. The first suggested worse outcomes were concentrated in patients with lower hematocrit levels (approximately 20%), whereas the second suggested there was little benefit to increasing the hematocrit level above 25%. The form of the relationship between continuous hematocrit levels and outcomes requires further study. Methods: In the two trials, 271 infants who underwent biventricular repair not involving the aortic arch were enrolled. Analysis was undertaken of the effects of hematocrit level, as a continuous variable, at the onset of low-flow cardiopulmonary bypass. Results: Psychomotor Development Index scores at age 1 year varied nonlinearly with hematocrit levels, with increasing scores up to 23.5% hematocrit (P < .001) and a plateau effect beyond 23.5% (P = .42), based on a piecewise linear model. Lower hematocrit levels were associated with more positive intraoperative fluid balance (P < .001 for linear trend) and marginally associated with higher serum lactate levels at 60 minutes after bypass (P = .08 for linear trend), but not with blood products given, nadir of cardiac index in the first 24 hours, or Mental Development Index scores. Conclusions: A hematocrit level at the onset of low-flow cardiopulmonary bypass of approximately 24% or higher is associated with higher Psychomotor Development Index scores and reduced lactate levels. Because the effects of hemodilution may vary according to diagnosis, age at operation, bypass variables such as pH strategy and flow rate, and other perioperative factors, this study cannot ascertain a universally "safe" hemodilution level.
UR - http://www.scopus.com/inward/record.url?scp=38649098135&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=38649098135&partnerID=8YFLogxK
U2 - 10.1016/j.jtcvs.2007.03.067
DO - 10.1016/j.jtcvs.2007.03.067
M3 - Article
C2 - 18242268
AN - SCOPUS:38649098135
SN - 0022-5223
VL - 135
SP - 355
EP - 360
JO - Journal of Thoracic and Cardiovascular Surgery
JF - Journal of Thoracic and Cardiovascular Surgery
IS - 2
ER -