Olfactory Stimulation by Vanillin Prevents Apnea in Premature Newborn Infants

Objective: Apnea is one of the most common problems in premature newborns. The present study aimed to determine the effect of olfactory stimulation by vanillin on prevention of apnea in premature newborns.
Methods: In this randomized controlled trial, 36 premature newborns with the postnatal age of 2 days and weight under 2500 grams referred to the hospitals affiliated to Shiraz University of Medical Sciences, were selected through simple random sampling and allocated into control and experimental groups. The experimental group received olfactory stimulation by saturated vanillin solution, while the control group received no interventions. The newborns of both groups were continuously monitored for presence/absence of apnea and number of episodes of apnea as well as arterial blood oxygen saturation and heart rate for 5 days. The data were analyzed by independent Student t-test and repeat measure ANCOVA.
Findings: The presence of apnea revealed to be significantly different between the two groups in the first, second, and fourth day of the study (P<0.05). The number of episodes of apnea during five days was also significantly different between the study groups (t=8.32, P<0.05). Using olfactory stimulation by vanillin caused a 3.1-fold decrease in apnea and the effect size was 0.72. Moreover, the two groups were significantly different regarding the arterial blood oxygen and heart rate during the study period (P<0.05).
Conclusion: This study indicated the beneficial effect of saturated vanillin solution on apnea; therefore, it may be used for prevention and treatment of apnea in premature infants. Further studies are needed to improve evidence-based practice in this regard.

Keywords
Vanillin; Apnea; Premature Infant; Newborn; Olfactory; Chemical Stimulation