To compare tidal volumes, inflating pressures and other ventilator variables of infants receiving synchronized intermitted mandatory ventilation with volume guarantee during emergency neonatal transport with those of infants receiving synchronized intermitted mandatory ventilation without volume guarantee.Retrospective observational study.A regional neonatal emergency transport service.We enrolled 77 infants undergoing emergency neonatal transfer. Forty-five infants were ventilated with synchronized intermittent mandatory ventilation with volume guarantee and 32 with synchronized intermitted mandatory ventilation without volume guarantee.Infants received synchronized intermitted mandatory ventilation with or without volume guarantee during interhospital emergency neonatal transport using a Fabian + nCPAP evolution neonatal ventilator (Software Version: 4.0.1; Acutronic Medical Instruments, Hirzel, Switzerland).We downloaded detailed ventilator data with 0.5 Hz sampling rate. We analyzed data with the Python computer language and its data science packages. The mean expiratory tidal volume of inflations was lower and less variable in infants ventilated with volume guarantee than in babies ventilated without volume guarantee (group median 4.8 vs 6.0 mL/kg; p = 0.001). Babies ventilated with synchronized intermittent mandatory ventilation with volume guarantee had on average lower and more variable peak inflating pressures than babies ventilated without volume guarantee (group median 15.5 vs 19.5 cm H2O;p = 0.0004). With volume guarantee, a lower proportion of the total minute ventilation was attributed to ventilator inflations rather than to spontaneous breaths between inflations (group median 66% vs 83%; p = 0.02). With volume guarantee, babies had fewer inflations with tidal volumes greater than 6 mL/kg and greater than 8 mL/kg (group medians 3% vs 44% and 0% vs 7%, respectively; p = 0.0001). The larger tidal volumes in the non-volume guarantee group were not associated with significant hypocapnia except in one case.During neonatal transport, synchronized intermittent mandatory ventilation with volume guarantee ventilation reduced the occurrence of excessive tidal volumes, but it was associated with larger contribution of spontaneous breaths to minute ventilation compared with synchronized intermitted mandatory ventilation without volume guarantee.