Modification of Trusler's Formula for the Pulmonary Artery Banding

BackgroundThe major difficulty of pulmonary artery banding (PAB) is optimal intraoperative adjustment. In this study, a target intraoperative shunt ratio (Qp/Qs) was utilised to evaluate a fixed Trusler's formula for the degree of PAB of infants destined for either univentricular or biventricular surgical route.MethodsTen consecutive infants (median age, 1.62 months) undergoing PAB through median sternotomy were studied. A fixed Trusler's formula (20 mm + 1 mm/kg body weight) was used to set the initial band size, and subsequent intraoperative adjustment was based on target Qp/Qs (using oxymetric data). Suitable target Qp/Qs was set ≤0.5 for the biventricular repair group (six patients) and ≤0.3 for the univentricular palliation group (four patients).ResultsIn the biventricular group, the target mean Qp/Qs of 0.4 was achieved according to the fixed formula. However the band size was narrower in the univentricular group by 2.25 mm to achieve the target mean Qp/Qs of 0.27 instead of a higher level (2.2) with the fixed formula.ConclusionUsing the intraoperative Qp/Qs calculation, the circumference of the band was in agreement with the fixed formula of Trusler for the biventricular repair group, however a narrower band size is recommended for the univentricualr palliation group.