Physiologic and Neurophysiologic Outcomes of Kangaroo Care

Susan M. Ludington, CNM, Ph.D., FAAN

Walters Professor of Pediatric NursingSusan.ludington@case.edu

Evolution of KMC Science

Case Studies Descriptive Studies Experimental

Studies Meta-Analyses Policies

Physiologic Outcomes

• Heart rate, stability, variability• Respiratory rate, stability, SaO2, apnea, PB• Temperature• Pain responses• All results cited in Ludington-Hoe et al., 2008. A

Clinical Guideline for Implementation of Kangaroo Care with Premature Infants of 30 or More Weeks Postmenstrual Age. Advances in Neonatal Care 8(3S), S3-S23. ( Supplement)

Heart Rate variables

• HR may not change or be different from incubator, or may rise 5 beats/min in KC

• HR usually higher in 2nd KC hour than 1st • Bradycardia is rare during KC• HR variability shows increased

sympathetic activity and overall predominance of parasympathetic activity during KC as compared to incubator

Respiratory Variables

• RR may be lower, or no different than in incubator or rise 10 breaths/min with KC

• RR usually more stable in KC (2nd sleep)• SaO2 may rise or drop 0.6 -1.0% with KC• Desats (Sao2<80%) increase in 2nd KC hr

in one study (Bohnhorst et al. 2004)

Breathing Patterns

• Apneas may not change or may decrease by 75% during KC

• A decrease in apneas is expected because apneas occur during arousals from sleep and sleep arousals drop during KC (Lehtonen & Martin, 2004).

• Periodic breathing decreases during KC

Temperature Changes

• Infant body temperature rises.• The coldest an infant will be is when he is

in an incubator or under a radiant warmer or swaddled

• In tropical environments, infant temps can exceed 38.0C with paternal KC.

• Each breast acts independently to keep a twin warm

Case Study #1

Data collection time

Tem

pera

ture

38.0

37.5

37.0

36.5

36.0

35.5

35.0

Subject #1

Maternal breast A

Baby A

Data collection time

Tem

pera

ture

38.0

37.5

37.0

36.5

36.0

35.5

35.0

Subject #1

Maternal Breast B

Baby B

Case Study # 1

Baby ABaby B

Pain Responses

• Heart rate is much less likely to rise with KC during pain as without KC or with sucrose

• Respiratory rate does not fluctuate so widely with KC during pain as without KC or with sucrose

• Crying may not occur with heelstick in KC, and crying time is greatly diminished with KC

Other physiologic responses• Cortisol levels (sign of stress) decrease during

as little as 20 minutes of KC compared to incubator period

• Weight gain is increased with KC• Head circumference is increased with KC• Body length is increased by 0.99 cm with KC• Fewer infections, probably due to increased

hydration, decreased water loss, and the dermal pathway of antigen/antibody transfer using D-squam (Case and Rainbow study in progress).

Neurophysiologic Outcomes

• Sleep indices• Brain Maturation • Brain Complexity• Cerebral Oxygenation

Neurophysiologic Outcomes

Neuroplasticity

• In first 3 years, the components of the brain and central nervous system can be changed by environmental events (internal and external environment).

• MALLEABILITY/FLEXIBILITY of the neurons, dendrites, axons, wiring, firing, and structure/function of brain.

Brain Growth Spurt

• During first and last trimesters of pregnancy brain grows very fast and is more receptive to environmental influences than at other times.

• Over 1st 3 years of life, brain reaches 75% of adult size

• Genetic contributions made by DNA which is laid down in neurons up to 12 months age, not after that.

Brain Maturation• Development of the brain that occurs over time:

– Nerves become covered with myelin sheath– Neurons grow larger (dendritic growth) (# is set by

term age)– Neurons connect with thousands of others to produce

thoughts, actions, feelings– Redundant neurons die off– Neurons travel from central germinal matrix to

periphery to form cortex in lobes and areas of brain– Communication between R and L hemispheres

occurs intelligence

Frontal LOBE

• Area of LIMBIC system –the emotional system of the human being

• The site for memory retention in the first 3 years of life – emotional memories establishing self-esteem, love, compassion, empathy, sympathy, importance, sense of belonging.

• Pleasing TOUCH is best stimulator of LIMBIC system. ( Ollauson et al., 2003)

Signs of Brain Maturation• Enlarging head size due to dendritic and cell body

expansion and migration• Increasing control over bodily functions, ie. -respiratory rate becomes more regular,

- heart rate becomes more regular- HR and RR become more cohesive(↓ RSA-respiratory sinus arrhythmia)- less physiologic and behavioral disruption with distrubance-sleep becomes more organized-brain firing patterns change and do so without damage-brain structure changes without damage (Scher 1997, Scher et al., 2002)

How to Measure Brain Maturation

1. SLEEP PATTERNS2. HEART RATE/RESPIRATORY RATE

PATTERNS3. BRAIN ACTIVATION by EEG patterns by

regular EEG (expensive) or by aEEG (amplitude EEG - using new bed side brain monitor) and by Near Infrared Sprectroscopy

Not so much duration, or density of any sleep stage, or number of sleep stage episodes, but, cycling between quiet sleep and active sleep is what is important

what is important in SLEEP

Active sleep =REM=Dream sleep=continuous EEG pattern

Quiet sleep =Non REM=NREM=No dreamsSynaptogenesis between neurons occurs in =discontinuous EEG pattern

Cycles take about 60 minutes to complete

Think of your pet, watching him sleep

REMREM REM

NREM NREM

This is a healthy sleep patternThis is a very good cycling pattern

So in every hour, you would like to see an EEG pattern that shows:

REM

NREM

REM

NREM

1 hour 2nd hour

But, In the NICU, infants demonstrate a very chaotic version of this cycling pattern.Cycling is needed for normal development. Quiet Sleep is needed to produce Active Sleep.

In any 3 hour period you should see 3 cycles between REM (dreaming)

sleep & NREM (quiet) sleep completed:

REM

NREM

REM

NREM

REM

NREM

State

HR

RR

REM Sleep is supposed to be somewhat active, so HR increases and RR is irregular

What do we see during Kangaroo Care?

Pre-KC: • Same as baseline patternIn KC: • Normal cycling & less magnitude in 2nd cycle• Few, if any, tachycardic/bradycardic • HR -variation is within normal limits• Non-chaotic pattern

chaotic pattern of activity,quiet HR & RR

Pre-KC KC

What does this mean?

In the cerebal cortex: Synapses between the 3 levels of neurons are occurring and synapses are becoming reinforced for longevity and complexity as needed to provide regular cycling

Cycling is needed for normal growth

Sleep Cycling

Neuronal Synapses & Growth

But preemies are demonstrating 48 hours of non-cycled sleep patterns

a) Does this continue thru hospitalization? YESb) Does the lack of cycling or delay in cycling affect

post-discharge sleep? No normal sleep pattern for two years post discharge (Scher, 1997)

• Maturation changes are reflected in the spectral characteristics of Respiration, ECG/Heart rate, Pulse oximetry, Chin EMG, Eye movements, EEG.CALLED DYSMATURITY INDEX and

DIMENSIONAL ANALYSIS OF COMPLEXITY

Test Conditions

Incubator Group

SSC Group

Results

Pediatrics 2006 report:

• Arousals were lower in SSC group than controls (p<.01) over entire study period as well as during test-pretest matched segments of QS (p<.0001) and AS (p<.007).

• REMs were lower in SSC period in SSC group (p <.01) and in AS segments (p < .02)

• Indeterminate sleep lower in SSC (p < .03) when confounders were included in the regression.

• QS increased during SSC

• State transitions decreased during SSC

Results with N=109Continued

Dysmaturity Index Findings

• When studied over 32-40 weeks:– Respiratory Regularity better than term & 44 wks– AS time better than term and 44 wks– Arousals the same as term – QS time better than term and 44 wks– Cycle length better than term and same as 44 wks– Spectral beta and spectral correlation better than term

and 44 wks– 5 areas of right hemisphere (the one that responds to

sensory stimulation) more mature than non-KC preterms

BETTER BRAIN MATURATION

• THIS SINGLE NURSING INTERVENTION IMPROVES BRAIN MATURATION. NO other single nursing intervention has been shown to do this (Scher M, Ludington-Hoe, SM, Kaffashi, F., Johnson, M, Holditch-Davis, D, & Loparo KA. Neurophysiologic assessment of brain maturation: preliminary results of an eight-week trial of skin contact with preterm infants. Sleep Medicine, 2008

Maturity by COMPLEXITY

• Complexity is called Dimensional Analysis• There are 3 measures we look at (sample

entropy, approximate entropy, probabalistic complexity, and deterministic complexity)

Complexity Results

• In all measures of complexity, preterm infants who received KC from 32-40 weeks pma had better brain maturation than fullterm infants and similar healthy preterms who did not get Kangaroo Care. (Kaffashi F, Scher M, Ludington-Hoe SM, & Loparo, KA. Complexity analysis of neonatal EEG. In press for J. Electroencephalography. )

Effect of Nursing Care on Brain Activation

• Near Infrared Reflective Spectroscopy is a measure taken by a machine that can be used at the bedside.

• It measures cerebral blood volume, blood flow, cerebral oxygenation, cerebral oxygenated and deoxygenated hemoglobin – all NON-INVASIVELY

• When brain tissue is activated, changes in blood flow cause change in oxygenation and this is picked up by machine

Effect of Nursing• Opening incubator doors • Handling• Heel Stick• Conversation• Blanket tucking• Overhead pagingEach reduced cerebral blood volume by 17-40% for 5-60

secondsThese occurred 28-45 times in a 2 hour periodSpectrometry picked up 63% more desaturation events than

SaO2 monitoring does (Gagnon, Leung & Macnab, 1999. A J Perinatol 16(1), 7-11).

Effects of Nursing

• Vital Signs are very disruptive to cerebral blood flow and– -Reduce blood flow by 14%– -Reduce blood volume by 8%– -Reduce oxygenation by 7-56%

– CHANGING DIAPERS is Similarly Disruptive(Adcock et al., 1999, Neonatal intensive care

applications of near-infrared spectroscopy. Clin Perinatol 26(4), 893-903)

Effects of Nursing

• Weighing the infant with lowered lights, sound, and containment of extremities vs. no change in environment- measured Pain, HR, SaO2, salivary cortisol, and cerebral oxygenation

• Weighing with environment change resulted in less pain, lower HR increase, no change in cortisol, and increased cerebral oxygenation levels. Better than no environment change.

Cateline, Tordjman, Morin, Oger, Sizun, 2005. Clinical, physiologic, and biologic impact of environmental and behavioral interventios in neonates during a routine nursing procedure. J Pain 6(12), 791-797.

Effect of Environment• The Loud and Well Nursery is still bad, because

it prevents/minimizes quiet sleep, sustains active sleep, minimizes good quality cycling.

• Though changes proposed in 1985 (Gottfried et al., Infant Stress Under Intensive Care), sound levels continue to be above recommended levels despite physical redesign of nurseries and staff training. Equipment, alarms, staff talking and infant fussiness contribute to even higher sound levels (Byers et al., 2006. Sound level exposure of high risk infants in different environmental conditions, Neonatal Network, 25(1), 25-32.)

Jackie Martin – Roanoke, VA NICU

• Comparing brain activation during incubator care and during KC

• Similar to heart rate variability, there appears to be increased activation of the brain during KC (improved cerebral blood flow and cerebral oxygenation probably mediated by stabilized cardiorespiratory parameters during sleep) as compared to incubator.

• So, if it were your infant, would you want the baby to have better or lesser brain blood flow and oxygenation? THIS IS A NO-BRAINER!!

This is the Best quiet time in the NICU for brain maturation

Kangaroo and Hand TouchFor the Limbic Brain!!!

Brain Outcomes

• Kangaroo Care is the best NON-SEPARATION. Separation from mother during stressful periods/painful procedures during the first two weeks of life permanently alters µOpioid receptor binding capacity in the brain in rats and is expected to do so in humans – a PERMANENTLY BAD change in the brain (Weaver SA, Diorio J, Meaney MJ. 2007. Maternal separation leads to persistent reductions in pain sensitivity in female rats. J. of Pain 8(12), 962-969.)