Dead space fractions in neonates following first-stage palliation for hypoplastic left heart syndrome

(1) To characterise changes in dead space fraction during the first 120 post-operative hours in neonates undergoing stage 1 palliation for hypoplastic left heart syndrome, including hybrid procedure; (2) to document whether dead space fraction varied by shunt type (Blalock-Taussig shunt and Sano) and hybrid procedure; and (3) to determine the association between dead space fraction and outcomes.

Retrospective chart review in neonates undergoing stage 1 palliation for hypoplastic left heart syndrome in a cardiac intensive care unit over a consecutive 30-month period. A linear mixed model was used to determine the differences in dead space over time. Multivariable linear regression and a multivariable linear mixed model were used to assess the association between dead space and outcomes at different time points and over time, respectively.

Thirty-four neonates received either a Blalock-Taussig shunt (20.5%), Sano shunt (59%), or hybrid procedure (20.5%). Hospital mortality was 8.8%. Dead space fractions in patients undergoing the hybrid procedure were significantly lower on day 1 (p = 0.01) and day 2 (p = 0.02) and increased over time. A dead space fraction >0.6 on post-operative days 3-5 was significantly associated with decreased duration of mechanical ventilation in all surgical groups (p 0.6 on post-operative days 3-5 was associated with lower duration of mechanical ventilation in all surgical groups. A more comprehensive, prospective assessment of dead space in this delicate patient population would likely be beneficial in improving outcomes.