Table 1.

Patients pathway from fetal diagnosis to surgery

Age	Event
20 w + 5 d	Prenatal diagnosis of TGA-IVS, no signs of a restrictive foramen ovale (FO)
36 w + 5 d	Prenatal ultrasound showing a mobile FO flap, opening up to two-thirds into the left atrium and allowing bidirectional flow. Does not meet criteria for an emergency BAS. Planned caesarean at 38 weeks, followed by admission to the neonatology intensive care unit with the possibility of urgent BAS
0 d 38 w + 3 d	Delivered by planned caesarean section due to maternal indication. Apgar score at 1, 5, and 10 min were 6, 7 and 8, respectively. First saturation measurement at 5 min was 25% (preductal). Heart rate was >100 bpm, and the infant was crying loudly
	CPAP with PEEP 8 cmH2O was started, and FiO2 was incrementally increased to 1.0, with pre-and post-ductal saturation measurements of 50% and 70%, respectively
0–1 h	CPAP with PEEP 7 (FiO2 1.0) was continued at the Neonatal ICU, with pre-and post-ductal saturations of 45–55% and 70–75%, respectively
0–6 h	Gradual increase of oxygen saturation to 85–90% (preductal) and 90–93% (post-ductal) with CPAP PEEP 6 and FiO2 0.8
	Blood gas analysis
	1st measurement (1.5 h post-birth): Capillary: pH: 7.02 pCO2: 10.8 kPa pO2: 3.7 kPa BE: −12 Lactate: 5.9 mmol/L O2 saturation: 49% Hb: 9.3 mmol/L 2nd measurement (2.5 h post-birth): Arterial: pH: 7.25 pCO2: 6.8 kPa pO2: 3.5 kPa BE: −6 Lactate: 2.4 mmol/L O2 saturation: 59% Hb: 7.3 mmol/L 3rd measurement (3.5 h post-birth): Arterial: pH: 7.33 pCO2: 4.6 kPa pO2: 5.2 kPa BE: −5 Lactate: 1.8 mmol/L O2 saturation: 55% Hb: 6.8 mmol/L
	Confirmation of diagnosis: TGA-IVS, aorta in right anterior position to the pulmonary artery, tricuspid semilunar valves, coronary anatomy 1LCx-2R (according to the Leiden Convention coronary coding system)1
3 d	Successful arterial switch operation with Lecompte maneuver and closure of the FO
32 m	Patient is doing well, no developmental delays or disorders. Good biventricular systolic function, mild neo-aortic root dilatation, trivial neo-aortic valve regurgitation, no pulmonary branch stenosis

BAS, balloon atrial septostomy; CPAP, continuous positive airway pressure; FiO₂, fraction of inspired oxygen; FO, oval fossa; IVS, intact ventricular septum; h, hours; m, months; PEEP, positive end-expiratory pressure; TGA, transposition of the great arteries; w, weeks.

¹Gittenberger-de Groot et al. J Thorac Cardiovasc Surg 2018;156:2260-9.