Electromyographic activity of preterm newborns in the kangaroo position: a cohort study

OBJECTIVE To compare the electromyographic activity of preterm newborns placed in the kangaroo position with the activity of newborns not placed in this position. DESIGN A cohort study. SETTING A Kangaroo Unit sector and a Nursery sector in a secondary and tertiary care at a mother-child hospital in Recife, Brazil. PARTICIPANTS Preterm infants of gestational age 27-34 weeks (n=38) and term infants (n=39). PRIMARY AND SECONDARY OUTCOME MEASURES Surface electromyography was used to investigate muscle activity in the brachial biceps at rest. 3 groups were designed: (1) preterm newborns in the kangaroo position (PT-KAN), where the newborn remains in a vertical position, lying face down, with limbs flexed, dressed in light clothes, maintaining skin-to-skin contact with the adult's thorax. Her electromyographic activity was recorded at 0 h (immediately before starting this position), and then at 48 h after the beginning of the position (but newborns were kept in the kangaroo position for 8-12 h per day) and at term equivalent age (40±1 weeks); (2) preterm newborns not in the kangaroo position (PT-NKAN), in which measurements were made at 0 h and 48 h; and (3) term newborns (T), in which measurements were made at 24 h of chronological age. RESULTS The Root Mean Square (RMS) values showed significant differences among groups (F(5,108)=56.69; p<0.001). The multiple comparisons showed that RMS was greater at 48 h compared to 0 h in the preterm group in the kangaroo position, but not in the group not submitted in the kangaroo position. The RMS in the term equivalent aged group in the kangaroo position was also greater when compared with those in the term group. CONCLUSIONS The kangaroo position increases electromyographic activity in the brachial biceps of preterm newborns and those who have reached the age equivalent to term.