Table 3.

Risk of bias assessment of included nonrandomized studies using the ROBINS-I tool

	Confounding	Selection of participants	Classification of interventions	Deviation from intended intervention	Missing data	Measurement of outcomes	Selection of the reported results	Overall risk of bias judgment
NMP studies
Ravikumar et al. [21]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Selzner et al. [22]	Moderate	Serious	Low	Low	Low	Low	Low	Serious
Bral et al. [23]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Liu et al. [26]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
HMP studies
Guarrera et al. [12]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Dutkowski et al. [13]	Moderate	Low	Low	Serious	Low	Low	Low	Serious
Guarrera et al. [14]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Van Rijn et al. [15]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Patrono et al. [16]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Schlegel et al. [17]	Moderate	Low	Low	Serious	Low	Low	Low	Serious
Ravaioli et al. [18]	Moderate	Low	Low	Low	Low	Low	Low	Moderate
Rayar et al. [19]	Moderate	Low	Low	Low	Low	Low	Low	Moderate

NMP, normothermic machine perfusion; HMP, hypothermic machine perfusion.