Hemolysis and cardiopulmonary bypass: meta-analysis and systematic review of contributing factors

Table 2 Summary of findings of published studies comparing plasma free hemoglobin (PFHb) and haptoglobin between vacuum assisted venous drainage (VAVD) and gravity assisted venous drainage (GAVD)

Vacuum assisted venous drainage compared to gravity assisted venous drainage in cardiac surgery patients underwent CPB
Outcomes	№ of participants (studies) Follow-up	Certainty of the evidence (GRADE)	Relative effect (95% CI)	Anticipated absolute effects
Outcomes	№ of participants (studies) Follow-up	Certainty of the evidence (GRADE)	Relative effect (95% CI)	Risk with placebo	Risk difference with Venous Drainage
Plasma Free Hemoglobin	170 (2 RCTs)	⨁⨁⨁⨁ High	–	The mean plasma Free Hemoglobin was 0	MD 5.37 higher (1.95 higher to 8.79 higher)

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI)
CI confidence interval, MD mean difference
GRADE Working Group grades of evidence
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect

ISSN: 1749-8090