Effect of hemofiltrated whole blood pump priming on hemodynamics and respiratory function after the arterial switch operation in neonates

BACKGROUND

Primed blood might have some deleterious effects on neonates during cardiopulmonary bypass (CPB) due to unbalanced electrolytes and inflammatory mediators. We hemofiltrated pump-primed blood before CPB to reduce inflammatory mediators and to adjust pH and the concentrations of electrolytes. The current study investigated the effects of hemofiltrated whole blood priming on hemodynamics and respiratory function after CPB in neonates.

METHODS

Patients who underwent the arterial switch operation in the neonatal period for transposition of the great arteries with intact ventricular septum were chosen for this study. Seventeen patients underwent CPB with hemofiltrated blood priming (group HF) and 23 patients underwent CPB with nonhemofiltrated blood priming (group N). The concentrations of electrolytes and bradykinin and high molecular weight kininogen of the primed blood before and after hemofiltration were measured. At 4 hours after completion of CPB, the left ventricular percent fractional shortening, and the relation between the mean velocity of shortening and the end-systolic wall stress (stress velocity index), were measured by echocardiogram in 7 patients in group HF and 6 patients in group N. Alveolar--arterial oxygen tension difference (AaDO2) and respiratory index (AaDO2 divided by arterial oxygen tension) were measured at several points for 48 hours after CPB in all patients.

RESULTS

Hemofiltration of the primed blood maintained electrolytes within a physiologic level and significantly reduced the concentrations of bradykinin (5,649 +/- 1,353 pg/mL versus 510 +/- 35 pg/mL, p < 0.05) and high molecular weight kininogen (52.7% +/- 3.2% versus 40.1% +/- 3.0% of normal plasma value, p < 0.05). The percent of fractional shortening at 4 hours after completion of CPB was significantly higher in group HF (n = 7) than in group N (n = 6) (22.0% +/- 0.7% versus 16.0% +/- 0.4%, p < 0.01). There was also a trend toward better stress velocity index in group HF than in group N (0.81 +/- 0.81 versus -2.17 +/- 0.45, p = 0.09). AaDO2 and respiratory index were significantly lower in group HF than in group N for 48 hours after CPB, respectively (p < 0.05).

CONCLUSIONS

Hemofiltrated fresh whole blood used for CPB priming attenuated cardiac impairment at early reperfusion periods and reduced pulmonary dysfunction in neonates with transposition of the great arteries with intact ventricular septum. This therapeutic strategy may have an advantage in preventing lung and heart dysfunction in pediatric patients who need CPB priming with blood.

The effect of dialyzer reprocessing on performance and beta 2-microglobulin removal using polysulfone membranes

Increased biocompatibility and lower cost are the two major arguments favoring routine dialyzer reprocessing. The impact of longer-term reprocessing is critical to the practical use of polysulfone membranes (PMs), because of the possibility of decreasing efficiency and performance, especially in the removal of beta 2-microglobulin (beta 2M), a protein that has been implicated in the development of dialysis-associated amyloidosis (DDA). In this study, we examine urea clearance (Kd), urea mass transfer coefficient (h0), ultrafiltration coefficient (K(uf)), and percent removal of beta 2M up to 24 uses. The study involved 11 patients on hemodialysis for 5.27 +/- 4.6 years, with a mean age of 62.5 +/- 9.7 years and average run-time treatment of 2.78 +/- 0.3 hours. PMs were tested after being reprocessed manually using bleach and formaldehyde. The efficacy of the dialyzer was examined on uses 1, 5, 10, 15, 20, and 24, and the percent removal of beta 2M was determined except in the twentieth use and corrected for ultrafiltration. The Kd obtained through 24 uses showed no significant change, although h0 was significantly increased in the fifteenth use, and K(uf) was significantly increased in the 10th and 20th use (P < 0.05). The percent removal of beta 2M increased significantly from 44.1 +/- 2.8 (mean +/- SEM) in the first use to 59.4 +/- 2.19 (P < 0.05) in the 10th use, and 62.1 +/- 4.07 and 63.1 +/- 4.27 in the 15th and 24th uses, respectively (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)