The Effect of Mechanical Ventilation Modes on Salivary Cortisol Levels of Premature Babies

Abstract Objective: Respiratory failure is common in preterm infants and mechanical ventilation treatment may be required. Pain and stress in newborns during mechanical ventilation may have negative effects on neurological development of the babies. Salivary cortisol level is one of the important non-invasive tests to detect stress. In this study, we aimed to examine the relationship between mechanical ventilation modes and stress levels by measuring salivary cortisol level of the preterm infants. Methods: The study group consisted of 65 preterm infants on respiratory support, and 43 control preterm infants. Neonatal Infant Pain Scale (NIPS) was used to evaluate the pain. To determine the stress level, salivary cortisol level was studied in saliva samples taken in the morning and in the evening on the 4th postnatal day. Results: The morning and evening salivary cortisol levels of the infants in the study group were found to be significantly higher than the babies in the control group (p<0.001; p<0.001, respectively). Both morning and evening salivary cortisol levels of infants on invasive mechanical ventilation were found to be higher than the cortisol values of infants on non-invasive mechanical ventilation (p<0.001; p<0.001, respectively). Pressure Support mode and Synchronised Intermittant Positive Pressure Ventilation mode did not differ in cortisol levels either in the morning or in the evening (p=0.402; p=0.391, respectively). However in non-invasive modes, nasal Synchronised Intermittant Mandatory Ventilation caused higher cortisol levels compared to nasal Continous Positive Pressure Ventilation mode both in the morning and in the evening samples (p=0.031; p=0.038, respectively). Conclusion: Increased salivary cortisol levels in invasive modes show that intubation causes pain and stress in newborns. For this reason, we assume that physicians and nurses have important duties for the pain and stress management of infants undergoing mechanical ventilation.