Research question: Can PBUF provide more physiologic values for glucose, sodium, potassium and lactate throughout the cardiopulmonary bypass period without an increased incidence of adverse events?
Background: The values for glucose, sodium, potassium and lactate in blood primes for subjects weighing less than 8 kg are known to be non-physiologic. The process of priming the cardiopulmonary bypass circuit is not standardized across institutions and there are several methods used to correct for known prime value issues. The investigators documented the prime values for 20 subjects weighing less than 8 kg and then performed pre-bypass ultrafiltration (PBUF) on the prime for those same circuits to achieve more physiologic prime values. The investigators were cautious not to implement too significant of a change as the investigators assessed the technique and documented that plasma-free hemoglobin importantly did not rise and that measured osmolality was still slightly above the normal range.
Study type: Prospective randomized controlled study.
Hypothesis: The investigators hypothesize that pre cardiopulmonary bypass ultrafiltration (PBUF) can provide more physiologic prime values for glucose, sodium, potassium and lactate. Plasma-free hemoglobin will not increase with the technique. Osmolality will be maintained slightly above the normal range. PBUF will not negatively impact clinical outcome measures and may improve them.
Specific Aim 1 To determine if use of PBUF will result in more physiologic values for glucose, sodium, potassium and lactate during and immediately after cardiopulmonary bypass.
Specific Aim 2 To determine if PBUF can be achieved with no increase in plasma free hemoglobin while maintaining plasma osmolality within acceptable range during and immediately after cardiopulmonary bypass.
Specific Aim 3 To determine if use of PBUF will result in improved clinical outcomes after surgery on cardiopulmonary bypass.
Randomization: Prior to surgery, subjects will be randomized to one of the two study groups using a randomly permuted blocks design.
Statistical analysis: Analyses will be performed on an intention to treat basis. Comparisons of subject characteristics and outcomes will be made using the two-sample t test or Wilcoxon rank sum test for continuous variables, and Fisher's exact test for categorical variables. If imbalances in patient factors exist between the two groups, linear and logistic regression will be used to compare outcomes for the groups adjusting for these potential confounders.
Sample size calculation: Sample size is calculated for comparisons of subjects in the normal range of values for the PBUF and standard care groups. This will be done separately for glucose, sodium, potassium, and lactate; each comparison will be performed at the 0.0125 level of significance. If 70% of standard care subjects are in the normal range versus 90% of PBUF subjects, a total of 176 subjects (88 per group) would be required to achieve 80% power. With 350 eligible subjects that meet inclusion criteria based on 2017 numbers and 75% consent rate the investigators will be able to enroll 260 subjects in 1 year.
Given COVID-19 restrictions, the study is on hold.
