Research Summaries

     A study conducted by Susan M. Ludington was aimed at determining how skin-to-skin (Kangaroo) contact affected the energy expenditure of preterm infants. This study was conducted on eight preterm infants. Four hypotheses were proposed for the study: heart rate of the preterm infant will decrease with skin-to-skin contact, sleep time will increase when compared to awake time with skin-to-skin contact, duration of the sleep state will increase, and preterm infant activity decreases with skin-to-skin contact.  These were important for Ludington to determine because other studies have shown that energy expended is less energy available for growth of the preterm infant.
     The preterm infants in this study were clothed only in a diaper for the skin-to-skin intervention. The infant was held in the upright position between the mother’s breasts. The mother was seated in a stationary chair beside the crib of the infant. During the pre and post skin-to-skin observation, the infants were placed in the left lateral position under two blankets wearing a t-shirt and a cap.
    No correlation between skin-to-skin contact and decreased heart rate occurred. However, the other three hypotheses were supported. There was an increased percentage of sleep time compared to awake time with skin-to-skin contact, the duration of the sleep state was increased with skin-to-skin contact, and preterm infant activity level was decreased during skin-to-skin. From these results, skin-to-skin contact is beneficial to the infant to decrease energy expenditures, thus increasing the energy available for growth. However, it must be considered that only eight infants participated in this study.
 

Charpak, N., Ruiz-Pelaez, J., Figueroa, Z., & Charpak, Y. (1997). Kangaroo mother versus traditional care for newborn infants =< 2000 grams: A randomized, controlled trail. Pediatrics 100(4), 682-688.

    This study was done to compare Kangaroo Mother Care to traditional care in low birth-weight (LBW) infants. The study was conducted in a tertiary hospital with infants less than or equal to 2000 grams. Out of 1084 infants, 786 were randomized. 382 of the infants had Kangaroo Care, and 364 of the infants had traditional care. This study was an open randomized, controlled trial. The LBW infants that participated in the Kangaroo Care portion of the trial were held upright for 24 hours attached to their mother’s chest, and the mothers acted as the infants’ incubators. The infants were kept in the upright position until they showed signs of rejecting the position by pushing away or crying. The mothers breastfed the infants and formula supplements were given by the mother as needed. The control infants were kept in an incubator.
    The results of this study revealed that overall infection in the Kangaroo Care infants was decreased in comparison to the traditional care infants. However, these infection rates were not significant. Growth was very similar between the two groups. Hospital stay was shorter in the infants who received kangaroo care. Kangaroo care has the advantage of decreased cost of health care. This is especially important in low socioeconomic groups that may not have resources to traditionally care for a LBW infant.
    The sample size for this study is adequate to determine the comparison between traditional and Kangaroo Care of the LBW infant. However, the applicability of this study is of concern to the US. Many mothers are unable to leave work in order to provide Kangaroo Care 24 hours a day. This probelem is especially evident in the case of single mothers. This study supports Kangaroo Care mainly with the correlation between Kangaroo Care and decreased hospital stay when compared to traditional LBW infant care. In addition, Kangaroo Care in this study had no more adverse effects than traditional care.

Ludington-Hoe, S., Anderson, G., & Hollingsead, A. (1999). Birth-related fatigue in 34-36-week preterm neonates: Rapid recovery with very early kangaroo (skin-to-skin) care. Journal of Obstetrical Gynecological and Neonatal Nursing 28(1), 94-100.

    This study of six 34-36 week neonates with 5 minute APGAR scores of 6 or greater suggest that Kangaroo Care in the delivery room may be beneficial to the neonates. These six neonates may not be representative of all 34-36 week neonates, but their progress is to be considered. The temperatures of theses neonates reached a thermoneutral range quickly. Heart rate, respiratory rate and oxygen saturation all remained normal for these infants during the Kangaroo Care, with very few exceptions. By 48 hours after birth, all neonates in the study were able to go home. These neonates received Kangaroo Care for six hours after birth. Two nurse researchers gathered the data on the neonates, and they alternated care of the mother and neonate to prevent bias. The neonates were breastfed during Kangaroo Care when they appeared hungry. Two of the neonates in the study had respiratory grunting prior to the Kangaroo Care, and this resolved along with warmed, humidified oxygen during Kangaroo Care. The neonates slept through most of the Kangaroo Care and appeared relaxed. Overall, this study suggests that Kangaroo Care started in the delivery room may help neonates to recover quickly from birth-related fatigue.

Legault, M. & Goulet, C. (1995) Comparison of kangaroo care and traditional methods of removing preterm infants from incubators. Journal of Obstetrical Gynecological and Neonatal Nursing 24(6), 501-506.

    Nurses need to establish a method of removing preterm infants from incubators to promote early parent-infant bonding, without exposing the infant to cold-stress. Legault and Goulet conducted a quasi-experimental study to compare the Kangaroo (skin-to-skin) with the traditional method (blanket-wrapped infants) of removing the infant from the incubator. This study, using a time-series design, was the first to measure the infants’ skin temperature, heart rate, respiratory rate, and oxygen saturation of each of the 71 mother-infant dyads subjected to both method. The mother’s satisfaction was also measured using the Maternal Satisfaction Questionnaire (15 items that rated satisfaction on a 5-point Likert scale) and a second questionnaire that noted the mother’s preferred method and an explanation for that choice.
     The Kangaroo Method produced little variation in physiologic parameters, with less variation in oxygen saturation and longer duration of testing than the traditional method, and heat production almost the same as an incubator. This method allows the infant to be held in a ventral position at an angle of ~ 60 degrees which decreased the compression of the diaphragm. Mothers expressed satisfaction with both methods since each gave them the opportunity to hold their newborns for the first time. However, the Kangaroo Method allowed more intimacy and therefore was preferred by most mothers. The Kangaroo Method is safe and allows early parent-infant bonding.

Bosque, E.M., Brady, J.P., Affonso, D.D., & Wahlberg, V. (1995). Physiologic measures of kangaroo versus incubator care in a tertiary-level nursery. Journal of Obstetrical Gynecological and Neonatal Nursing 24(3), 219-226.

    This prospective study was conducted to determine the safety and feasibility of prolonged Kangaroo Care of very-low-birth-weight infants in a tertiary-level nursery in terms of the amount of apnea, bradycardia, and oxygen desaturation. A convenience sample of 8 mother-infant pairs participated in a long-term (3 weeks), repeated measure design study in which kangaroo care was implemented 4 hours a day, 6 days a week and compared to pre- and post-kangaroo care in incubators. Heart rate, respiratory rate, % sleep time, and skin temperature were measured daily and recorded continuously on a polygraph for 8 hours each week.
    Apnea, bradycardia, and oxygen saturation, heart rate, and respiratory rate of kangaroo care were similar to incubator care. Although the percent sleep time and skin temperature were lower during kangaroo care, the difference were statistically but not clinically significant.

Bauer, J., Sonthaimer, D., Fischer, C., & Linderkamp, O. (1996). Metabolic rate and energy balance in very low birth weight infants during kangaroo holding by their mothers and fathers. The Journal of Pediatrics, 129(4), 608-611.

    This study was conducted to compare the effects of parental Kangaroo Care on oxygen consumption, carbon dioxide production, energy expenditure, temperatures (skin and rectal), heart rate, respiratory rate, arterial oxygen saturation, and behavioral states.  Eleven very low birth weight infants were studied before, during, and after kangaroo care. A cardiorespiratory monitor continuously monitored heart rate, respiratory rate, and oxygen saturation. Infant skin (lower leg) and rectal temperatures, and the skin temperature of the parent, were continuously recorded. The Prechtl Behavioral State Scale (5 behavioral states describing the level of eye opening, respirations, movement, and crying) was used to record the infant behavior throughout the study.  A Deltatrac II metabolic monitor was used intermittently to recorded oxygen consumption and carbon dioxide production and used to calculate the respiratory quotient and energy expenditure.
    Parental Kangaroo Care had no effect on heart rate, respiratory rate, arterial oxygen saturation, oxygen consumption, or carbon dioxide production.  Parental Kangaroo Care did increase the infants skin temperature, with a greater increase in core and skin temperature, heart rate, and respiratory rate during paternal rather than maternal Kangaroo Care.  These results suggest increased oxygen consumption during paternal Kangaroo Care, since oxygen consumption increases linearly with rising heart rate. The increase in skin temperature is not associated with the increase in rectal temperature or increase oxygen consumption and therefore the skin temperature increase was due to conduction of heat from the parent and not as a result of increased heat production. Kangaroo Care does not adversely effect energy expenditure.

Tessier, R., Cristo, M., Velez, S., Giron, M., Figueroa de Calume, Z., Ruiz-Palaez, J.G., Charpak, Y., & Charpak, N. (1998). Kangaroo mother care and the bonding hypothesis. Pediatrics 102(2), 390-391.

    This randomized, controlled trial included 488 mother-infant dyads who were studied to determine the effect of Kangaroo Care on the mother’s feelings and perceptions of her premature birth experience (degree of competence, worry, stress, social support) and on mother-infant bonding. The participants were randomly divided into two groups: the Kangaroo Mother Care (KMC) group in which mothers maintained skin-to-skin contact 24 hours a day and the traditional care (TC) group in which the infants were kept in incubators. The Mother’s Perception of Premature Birth Questionnaire (a 5-point Likert scale) addressed the mother’s perception of social support, feelings and worries of her LBW infant, and her sense of competence at 24 hours after birth and when the infant reached 41 weeks’ gestational age. The mother and infant were observed during breastfeeding at  41 weeks of gestational age and emotional bonding was assessed using the Nursing Child Assessment Feeding Scale.
     Mothers in the KMC group felt more competent, especially when Kangaroo Care began soon after birth (healthier infants had early close contact with their mothers).  Although infants with poor to bad health status at birth have delayed onset of the intervention, Kangaroo Care is also beneficial during their perinatal period. Mothers in the KMC group felt more isolated than those in the TC group, especially those whose infants stayed in the hospital longer. This difference may be due to an overwhelming feeling of responsibility without sufficient help. Social support should be added to KMC intervention. The infant’s health status may be a greater factor of the mother’s more sensitive behavior than Kangaroo Care. Kangaroo Care did not produce a bonding effect, but rather a resilience effect.