Table 3

Initiation criteria for iNO in all of the included studies

	Author	Initiation criteria for iNO
	Author	PH diagnosis	Echocardiographic findings	Surrogate marker of disease severity	Others
1	Ballard et al, 20068	N/A	N/A	MAP×FiO₂	N/A
2	Ballard et al, 201611	N/A	N/A	MAP×FiO₂	N/A
3	Hasan et al, 20179	N/A	N/A	N/A	N/A
4	Truog et al, 201410	N/A	N/A	N/A	N/A
5	Hsiao et al, 201920	Echocardiography	Details were not available	N/A	N/A
6	Nakanishi et al, 20234	N/A	N/A	N/A	N/A
7	Oka et al, 202313	Echocardiography (24%)	TR (PA >40 mmHg) D-shaped LV	OSI=MAP×FIO₂×100/SpO₂	N/A
8	Fraga et al, 202314	Echocardiography	RV pressure >½ sSBP estimated from TRJV. Bidirectional or right-to-left shunting through a PDA. Septal flattening or bowing at end-systole. TPV:RVET ratio, 0.2–0.3, moderately elevated PAP; ≤0.2, significantly elevated PAP.	N/A	N/A
9	Nakao et al, 201222	N/A	N/A	Oxygenation index	N/A
10	Iwatani et al, 202221	Cyanosis echocardiography	TR D-shaped LV	N/A	N/A

FiO_2, fraction of inspired oxygen; HRF, hypoxic respiratory failure; iNO, inhaled nitric oxide; LV, left ventricle; MAP, mean airway pressure; OSI, oxygen saturation index; PaO₂, partial pressure of oxygen; PAP, pulmonary artery pressure; PDA, patent ductus arteriosus; RV, right ventricle; RVET, right ventricular ejection time; SpO₂, peripheral oxygen saturation; sSBP, systolic systemic blood pressure; TPV, tricuspid peak velocity; TR, tricuspid regurgitation; TRJV, tricuspid regurgitant jet velocity.