1. Specific Bypass Conditions Determine Safe Minimum Flow Rate
Vesa Anttila, MD, Ikuo Hagino, MD, David Zurakowski, PhD, Yusuke Iwata, MD, Lennart Duebener, MD, Hart G.W. Lidov, MD, Richard A. Jonas, MD 
The Annals of Thoracic Surgery 
Volume 80, Issue 4, Pages (October 2005)
DOI: /j.athoracsur
Copyright © 2005 The Society of Thoracic Surgeons Terms and Conditions

2. Fig 1
Functional capillary density (FCD): FCD was lower after 34°C low-flow period to 15°C and 25°C (*p < 0.05). FCD was lower after low-flow period with 10 mL/kg/min flow rate compared to 25 and 50 mL/kg/min flow rate (*p < 0.05). For animals subjected to temperature of 34°C during the low-flow period, the subgroup with the lowest flow rate (10 mL·kg−1·min−1) had significantly lower FCD values compared with all other groups (p < 0.001). Temperature and flow rate were found to be significant multivariable predictors of FCD during rewarming (F = 31.0, p < 0.001, and F = 30.6, p < 0.001, respectively).
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2005 The Society of Thoracic Surgeons Terms and Conditions

3. Fig 2
Tissue oxygenation index (TOI): univariate analysis indicated that temperature and flow rate had a significant impact on TOI (p < 0.001, ANOVA, F test). However, regarding the duration of low flow or hematocrit, there were no significant differences (p = 0.49 and p = 0.07, t tests, respectively). Multivariate analysis detected a highly significant effect for temperature (F = 54.5, p < 0.001) and flow rate (F = 32.5, p < 0.001) on TOI. No temperature and flow rate interactions were found (p = 0.21). (*p < 0.05.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2005 The Society of Thoracic Surgeons Terms and Conditions

4. Fig 3
During rewarming, the functional capillary density (FCD) was negatively correlated with functional outcome (neurologic deficit score [NDS]) on postoperative day 1 (POD1). (r = -0.66, p < 0.001). Multiple regression indicated that FCD is a predictor of NDS (POD1) independent of flow rate and temperature. The fitted regression equation (solid line) for predicting NDS (̂) in points from FCD (x) is: ̂ = 260 – 2.2x.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2005 The Society of Thoracic Surgeons Terms and Conditions

5. Fig 4
An inverse correlation was found between the tissue oxygenation index (TOI) and the neurologic deficit score (NDS) on postoperative day 1 (POD1; r = -0.45, p < 0.001). Multiple regression analysis indicated that TOI is a predictor of NDS (POD1) independent of flow rate and temperature. The fitted regression equation (solid line) for predicting NDS (̂) in points from TOI (x) is: ̂ = 315 – 3.5x.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2005 The Society of Thoracic Surgeons Terms and Conditions

6. Fig 5
No damage was found in the cerebrum, except in animals undergoing a bypass temperature of 34°C and a flow rate 10 mL·kg−1·min−1(ml/kg/min). The total histologic score in this group was significantly higher compared with other groups (median scores, 11 versus 0; p < 0.001).
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2005 The Society of Thoracic Surgeons Terms and Conditions