(389) Maternal Physiologic Adaptations During Transport

Objective: Maternal physiologic adaptations during maternal transportation are not well understood. We sought to describe the fetal and maternal changes during maternal transport as described by maternal physiologic parameters, according to transport type.

Study Design:

We evaluated maternal physiologic changes in all maternal transports from 5/2021-5/2022 at a single, level IV maternal care facility. Patients with a singleton, non-anomalous viable fetuses were evaluated. All patients had pre-transport and intra-transport maternal vital sign assessment, which were analyzed and compared by transport type – ground, flight rotor or fixed wing. Maximum altitude for each transport was also recorded. Patients were excluded due to missing participant data. Mann Whitney U and Chi-square tests were used as appropriate.

Results:

85 transports occurred during the study period with complete vital sign information, 51 (60%) by rotor/fixed wing transport and 34 (40%) by ground transport. Most of the transports were for PPROM and PTL. There was no difference in age, BMI, parity, race, and type of insurance between the type of transport. Compared to patients transferred via ground transport, the patients transported via flight-rotor and fixed wing, were more likely to be from a rural designated hospital (p < 0.001). Maternal oxygen saturations were noted to decrease significantly in rotor/fixed wing transports (-1.0, [-3,0]) compared to those transported via ground (0, [0, 1] p=0.007; Figure/Table). Other vital signs – heart rate, blood pressure and respiratory rate did not differ between flight and ground transport (p >0.05, Table). Upon further examining vital signs for flights below and above altitudes of 3000 feet, there were no statistically significant difference.

Conclusion: There are changes in maternal oxygen saturations in individuals who are transported via air transport. Current physiologic thresholds should be updated when undergoing maternal transport.