Frequency-modulated orocutaneous stimulation promotes non-nutritive suck development in preterm infants with respiratory distress syndrome or chronic lung disease

Abstract

Objective: For the premature infant, extrauterine life is a pathological condition, which greatly amplifies the challenges to the brain in establishing functional oromotor behaviors. The extent to which suck can be entrained using a synthetically patterned orocutaneous input to promote its development in preterm infants who manifest chronic lung disease (CLD) is unknown. The objective of this study was to evaluate the effects of a frequency-modulated (FM) orocutaneous pulse train delivered through a pneumatically charged pacifier capable of enhancing non-nutritive suck (NNS) activity in tube-fed premature infants.

Study design: A randomized trial to evaluate the efficacy of pneumatic orocutaneous stimulation 3 × per day on NNS development and length of stay (LOS) in the neonatal intensive care unit among 160 newborn infants distributed among three sub-populations, including healthy preterm infants, respiratory distress syndrome (RDS) and CLD. Study infants received a regimen of orocutaneous pulse trains through a PULSED pressurized silicone pacifier or a SHAM control (blind pacifier) during gavage feeds for up to 10 days.

Result: Mixed modeling, adjusted for the infant's gender, gestational age, postmenstrual age and birth weight, was used to handle interdependency among repeated measures within subjects. A significant main effect for stimulation mode (SHAM pacifier vs PULSED orosensory) was found among preterm infants for NNS bursts per min (P=0.003), NNS events per min (P=0.033) and for total oral compressions per min (NNS+nonNNS) (P=0.016). Pairwise comparison of adjusted means using Bonferroni adjustment indicated RDS and CLD infants showed the most significant gains on these NNS performance indices. CLD infants in the treatment group showed significantly shorter LOS by an average of 2.5 days.

Conclusion: FM PULSED orocutaneous pulse train stimuli delivered through a silicone pacifier are effective in facilitating NNS burst development in tube-fed RDS and CLD preterm infants, with an added benefit of reduced LOS for CLD infants.

Figure 1

The NTrainer System handpiece and silicone pacifier assembly with an infant. Handpiece can be configured for the SHAM or PULSED conditions.

Figure 2

Probability distribution of GA and treatment starting PMA’s among preterm groups. [C = control SHAM, and NT = PULSED treatment conditions].

Figure 3

Minute-rate for NNS burst production among three preterm groups (HI-healthy infants, RDS-respiratory distress syndrome, and CLD-chronic lung disease). Groups were randomized to either SHAM or PULSED pacifier treatments. Significant main effect for stimulus condition (* p<.05, d=.41), and Bonferroni pairwise comparisons (** p<.05, d=.36; *** p<.01, d=.46). Error bars depict standard deviation.

Figure 4

Minute-rate for NNS Events among three preterm groups (HI-healthy infants, RDS-respiratory distress syndrome, and CLD-chronic lung disease). Groups were randomized to either SHAM or PULSED pacifier treatments. Significant main effect for stimulus condition (* p<.05, d=.36), and Bonferroni pairwise comparison for CLD infants (** p<.05, d=.42). Error bars depict standard deviation.

Figure 5

Minute-rate for NNS and nonNNS Oral Compressions among three preterm groups (HI-healthy infants, RDS-respiratory distress syndrome, and CLD-chronic lung disease). Groups were randomized to either SHAM or PULSED pacifier treatments. Significant main effect for stimulus condition (* p<.05, d=.41), and Bonferroni pairwise comparison for CLD infants (** p<.01, d=.50). Error bars depict standard deviation.

Figure 6

Length-of-stay (LOS) among three preterm groups (HI-healthy infants, RDS-respiratory distress syndrome, and CLD-chronic lung disease). Groups were randomized to either SHAM or PULSED pacifier treatments. A significant group by treatment interaction effect was present (p<.001), and Bonferroni pairwise comparisons for RDS (** p<.01, d=.47) and CLD infants (*** p<.05, d=.39). Error bars depict standard deviation.