sandra l. smith, phd, aprn, nnp-bc associate professor university of louisville, school of nursing
DESCRIPTION
The Effect of Mechanical Tactile Stimulation on Autonomic Nervous System Function in Preterm Infants. Sandra L. Smith, PhD, APRN, NNP-BC Associate Professor University of Louisville, School of Nursing [email protected]. Consequences of Neonatal Stress. - PowerPoint PPT PresentationTRANSCRIPT
The Effect of Mechanical Tactile Stimulation on Autonomic Nervous System Function in Preterm Infants
Sandra L. Smith, PhD, APRN, NNP-BCAssociate Professor
University of Louisville, School of [email protected]
Environmental Sources of Neonatal Stress
Painful procedures Noise and lighting Maternal separation Temperature fluctuation Hypoxia and hyperoxia
Glucocorticoids Oxygen consumption Energy expenditure Temperature fluctuations Hypoxemia
Consequences of Neonatal Stress
The stress response is meant to be limited and of short durationMassage may improve vagal activity, sleep, and growth by attenuating the
stress response (Arora et al., 2005; Diego et al., 2003, 2007; Field et al., 2006)
STRESS
Hypothalamus
Pituitary
Adrenal
MedullaCortex
CatecholaminesGlucocorticoids
Sympathetic‘fight or flight’
Parasympathetic‘rest & recovery’
++ GC, Catecholamines,Overriding SNS response
-- GC, Catecholamines,SNS/PNS balance
PHYSIOLOGIC INSTABILITY↑ HR, RR, BP
PHYSIOLOGIC STABILITYNormal HR, RR, BP
HPA AXIS
L O U I S V I L L E . E D U
HypothesisIn preterm infants, twice daily mechanical tactile stimulation (MTS) will promote autonomic nervous system function as
measured by heart rate variability (HRV)
L O U I S V I L L E . E D U
ScreenedN=175
IneligibleN=44
EligibleN=131
EnrolledN=52
MTSN=27
Incomplete DataN=10
ControlN=25
Incomplete DataN=5
ControlN=20
MTSN=17
Procedures and Testing Schema
• Medically stable 29-32 week preterms• Randomized to MTS or Control
• MTS: 20 minute prescribed compression and manipulation of soft tissues followed by joint flexion/extension
• Masked to HCP and Parents• LMTs provided MTS and Control
L O U I S V I L L E . E D U
Infant Characteristics
MTS ControlGender 8F/9M 11F/9M
Ethnicity47% Hispanic
53% White13% Hispanic
7% White
Birth PMA (wk) 31.6 ± 0.8 31.3 ± 0.9
Entry PMA (wk) 32.7 ± 0.8 32.3 ± 0.7
Birth Weight (g) 1522 ± 238 1598 ± 277
Entry Weight (g) 1522 ± 238 1590 ± 272
Weight @ Study End
2186 ±352 2247 ±337
Smith et al., J.Perinatol., 2012
• Cyclical change in R-R interval mediated by the ANS– The interaction and adaptability of SNS and PNS
• ECG data were acquired continuously prior to, during, and post MTS or CTL– Pre, during, and post session epochs were extracted for
analysis– HRV measures were calculated from the ECG
• Fast Fourier Transform (FFT) analysis– Estimates cardiac modulation by ANS– Regions are specific to the SNS and PNS
HRV
Burr, 1992; David et al., 2007; Malik & Camm, 1993; Longin et al., 2006; Ori et al., 1992; Patural et al., 2004; Sanhi et al., 2000
HRV Regions of ANS Activity
Sympathetic nervous system (0.02-0.2 Hz)
Parasympathetic nervous system (>0.2 – 2.0 Hz)
LF/HF ratio Higher = Sympathetic Lower = Parasympathetic
0.2 .02 2.0 Hertz
wk 0 wk 1 wk 2 wk 3 wk 40
2
4
6
8
10
12
14
16
18
MTSControl
LF:H
F R
atio
(SEM
)
wk 0 wk 1 wk 2 wk 3 wk 40
2
4
6
8
10
12
14
16
18*
‡
*
Males (n = 18) Females (n = 19)
*p < 0.5 between MTS & CTL at wk 3 and 4‡p < 0.05 MTS & CTL baseline to wk 4 J.Perinatol. (2012)
PRE SESSION
wk 0 wk 1 wk 2 wk 3 wk 40
5
10
15
20
25
LF:H
F R
atio
(SEM
)
wk 0 wk 1 wk 2 wk 3 wk 40
5
10
15
20
25
MTSControl
Males (n = 18) Females (n = 19)
J.Perinatol. (2012)NS between groups by sex
MTS or CTL SESSION
wk 0 wk 1 wk 2 wk 3 wk 40
2
4
6
8
1012
141618
wk 0 wk 1 wk 2 wk 3 wk 40
2
4
6
8
10
12
14
16
18
LF:H
F R
atio
(SEM
) MTSControl
Males (n = 18) Females (n = 19)
*
*p < 0.5 between MTS & CTL at wk 3 (J.Perinatol., 2012)
POST SESSION
HRV 6 HOURS POST SESSION WEEK 2Males (4 MTS, 4 CONTROL)
baseline cares sleep cares sleep4
5
6
7
8
9
10
11 MassageControl
LF:H
F R
atio
(SEM
)
Smith, et al. unpublished data
L O U I S V I L L E . E D U
Conclusions• Twice daily MTS promoted improved HRV in preterm
male infants• The trajectory of LF:HF ratio in MTS males
approximates those of the term infant reported by Patural et al. (2008)
• The MTS intervention did not increase LF:HF ratio; thus MTS appears non-stressful
• A well delivered intervention may improve male infant’s adaptation to stressful events
• The long term effects of MTS on preterm infant adaptation to daily stressors is unknown
L O U I S V I L L E . E D U
• Laurie Moyer-Mileur, PhD• Shannon Haley, PhD, LMT and team of LMTs• Hillarie Slater, BS• Robert Lux, PhD• Nancy Allen, ECG technician• Funding
– NIH NCCAM R 21 (LMM, PI)– University of Utah Interdisciplinary Research Grant, College
of Nursing, and Department of Pediatrics
Acknowledgements