Correlazione tra diminuzione del tono vagale e gravità della Disfunzione Somatica in neonati pretermine di peso molto basso alla nascita, valutata con la variabilità della frequenza cardiaca dello spettro di frequenza e cortisolo salivare

Abstract

ABSTRACT
Osteopathic manipulative treatment (OMT) is evolving in the neonatal intensive care unit (NICU) setting. Studies showed its efficacy in length of stay and hospitalization costs reduction. Moreover, it was suggested that OMT has a modulatory effect on the preterm infants’ autonomic nervous system (ANS), influencing saturation and heart rate. Even if OMT is based on the palpatory examination of the somatic dysfunctions (SD), there are controversies about its identification and clinical relevance. The objective of this study was to evaluate the inter-rater reliability, clinical characteristics, and functional correlation of the SD Grade score with the heart rate variability (HRV) and the salivary cortisol (sCor) using a multivariate linear model approach. To evaluate those features, we implemented an ad hoc SD examination for preterm infants that was performed by 2 trained osteopaths. It was based on the new variability model of SD that includes an SD Grade assessment procedure. The ANS features were assessed by frequency parameters of HRV studying high frequency (HF), low frequency (LF), and HF/LF, whereas sCor was tested with a radioimmunoassay. The ANS assessment was standardized and performed before SD testing. Sixty-nine premature infants were eligible. SD Grade showed excellent concordance between the blinded raters. Using SD Grade as a grouping variable, the infants presented differences in GA, Apgar, pathological findings, length of stay, and ventilatory assistance. In our multivariate model, HF, LF, and LF/HF resulted linearly correlated with SD Grade. Instead, sCor presented a linear correlation with 5’ Apgar and respiratory distress syndrome but not with SD Grade. SD Grade was in line with the natural history of the underdevelopment due to prematurity. Our models indicate that the cardiac vagal tone is linearly related with SD Grade. This finding may improve the multidisciplinary decision making inside NICU and the management of modifiable factors, like SD, for cardiac vagal tone regulation.

METHODS
In order to investigate the autonomic regulation in preterm infants and its correlation with SD Grade, we performed a single-center cross-sectional study based on the data recorded during the daily clinical practice in the period between February 2017 and October 2018 in the tertiary level of the NICU of Del Ponte Hospital in Varese. All the infants’ families provided the signed informed consent for the use of these data for research purposes. The Provincial Ethics Committee of Varese approved the study on February 14, 2017 and all the peri- and postnatal data were retrieved from an electronic dataset; they included information about demographic entities, delivery, medical procedures, and perinatal and maternal information. We assessed SD referring to the examination of the VM within NZ.

RESULTS:

Sixty-nine patients were examined, 35 males (51%) and 34 females (49%), with a mean GA of 28.9 ± 2.4 days and a mean birth weight of 1103.4 ± 274.1 g.

The SD grading assessment revealed 0 patients with SD Grade 0 or Grade 1; this result makes us understand how a premature baby always shows significant fascial adaptations. Within the sample, 40 (58%) patients showed a SD Grade 2 and 29 (42%) a SD Grade 3. At birth, the mean Apgar 5’ score of the entire sample was 7.96 ± 1.18 and 39 (56%) of them were delivered by Cesarian section.

Among clinical variables stratified by SD Grade, the body weight, GA, Apgar 5’, RDS, Jaundice, length of stay (LOS), and time to autonomous respiration (TAR) demonstrated a statistically significant difference, as reported in Table 1. The reliability of the SD Grade was measured based on the results reported by 2 experienced, board-certified, osteopaths who were blinded to the exam results of the peer-rater. Notably, in this specific setting, the global agreement for SD Grade on 69 preterm infants was excellent with an ICC of 0.864 (0.773–0.918).