Simulated kangaroo care in very preterm infants does not reduce physiological instability: the COSYBABY randomised controlled cross-over trial

Abstract

Introduction: Infants who are born very preterm experience frequent episodes of physiological instability including apnoea, oxygen desaturation and bradycardia due to immaturity of the pulmonary and nervous systems. Parental contact, such as kangaroo care, may reduce physiological instability. However, there may be long periods when parents cannot be with their baby. The BABYBE SYSTEM® is a medical device designed to simulate kangaroo care.

Methods: We conducted a randomised cross-over trial to determine whether episodes of apnoea and other episodes of physiological instability were reduced when infants were on an active BABYBE mattress. Each infant was included in the study for five consecutive days, with successive 12-h periods of the BABYBE® mattress being switched on or off. Episodes of physiological instability were identified from recordings of the vital signs monitors and compared with clinical notes. Generalised estimating equations models were used to compare physiological instability when the BABYBE mattress was switched on vs. off.

Results: A total of 23 infants born before 32 weeks' gestation were included in the main analysis. There was no significant difference between the number of apnoeic episodes infants experienced in the 12-h period when the BABYBE mattress was on compared with when the mattress was switched off (difference between conditions = 1.5 apnoeas, 95% CI: -0.2-3.2, p = 0.09). The number of episodes of apnoea identified from vital signs recordings were much higher than those documented in the clinical records (a total of 1,157 apnoeic episodes were identified across all infants from vital signs recordings compared with a total of 27 documented in clinical/nursing notes of the same infants).

Discussion: This trial does not provide evidence of a benefit of the BABYBE mattress for improving physiological stability in preterm infants. This study provides confirmation of the under-recognition of apnoeic episodes in clinical notes and the benefit of assessing electronic recordings of vital signs to gain a more complete picture of physiological stability.

Keywords: apnoea; bradycardia; desaturation; kangaroo care; newborn; preterm.

Figure 1

Participant flow chart.

Figure 2

Frequency of episodes of apnoea and example recording. (A) Histogram of number of apnoeas in each infant averaged over the 12-h recording periods (including periods when the BABYBE mattress was on and off). (B) An example apnoea identified from the vital signs recordings. Top row shows the impedance pneumography (IP) signal, with clear oscillations indicating chest wall movement before the apnoea. An apnoea of 23 s is indicated by the grey shaded area, detected using the algorithm developed and validated in independent infants (8) (see Methods). The heart rate and oxygen saturation subsequently drop. A second apnoea of 20 s also causes a drop in heart rate and oxygen saturation.

Figure 3

Episodes of physiological stability when infants were on the active BABYBE mattress compared with when the mattress was off. Average number of apnoeic episodes (A,B), bradycardias (C,D) and oxygen desaturations (E,F) when infants were on the active BABYBE mattress (red) compared with when the mattress was off (black). Data is presented as an average across all 12-h recording periods (A,C,E) and across each of the 12-h recording periods (B,D,F). The infants were randomised to initially start the trial on the BABYBE mattress (n = 12, indicated with circular points in B,D,F) or with the mattress switched off (n = 11, indicated with square points in B,D,F). Crosses/points indicate the median and error bars indicate the lower and upper quartiles.