Effects of routine procedures on salivary cortisol in mechanically ventilated neonates

Even though the stress secondary to invasive procedures has been investigated, less attention has been paid to the stimulation or pain caused by routine procedures on neonates. The changes in salivary cortisol concentration in mechanically ventilated NICU patients during routine procedures were monitored to provide reference and guidance for pain management. 80 mechanically ventilated neonates in the hospital from Sep 2021 to Mar 2022 were selected. The salivary cortisol levels of the neonates were monitored during nursing procedures and were categorized by their risk levels to the following groups: high-risk (endotracheal suctioning and arterial blood sampling), moderate-risk (gastric tube insertion, venipuncture), and low-risk (bedside bathing and diaper changes). The changes in heart rate were also recorded and compared. The concentration of cortisol in the saliva of the neonates was 1.5 ± 0.8 nmol/L during the sleeping state, 6.2 ± 1.3 nmol/L during endotracheal suctioning, 6.4 ± 1.4 nmol/L during arterial blood sampling, 6.1 ± 1.2 nmol/L during venipuncture, 4.4 ± 1.1 nmol/L during gastric tube insertion, 3.5 ± 0.8 nmol/L during bedside bathing, and 3.3 ± 0.9 nmol/L during a diaper change. The results revealed a statistically significant effect between routine procedures on salivary cortisol levels. Compared with the neonates in the control sleep state, there was a significant (P < 0.05) change in salivary cortisol concentration of infants undergoing high and moderate-risk nursing procedures. There was a small but significant (P < 0.05) change in salivary cortisol levels in infants who underwent low-risk procedures compared to infants in the control sleep state. Further, the fluctuation of salivary cortisol levels in routine procedures was more frequent compared with routine handling at night. The fluctuations of salivary cortisol concentration in high-risk procedures were larger than that of infants who underwent low-risk procedures, with the difference being statistically significant (P < 0.05). It was also determined that the top four influencing factors on the infants' heart rate were arterial blood sampling venipuncture, intubation, endotracheal suctioning, and gastric tube insertion (P < 0.05). Monitoring the saliva cortisol concentration index and heart rates can reflect the impact of different routine procedures on newborns and can be used to manage neonatal pain in the future.