The “regular preemie”

and the VSBW preemie

By Elizabeth Kelley Buzbee AAS, RRT-NPS, RCP

Infant mortality • Infant mortality is defined

as the number of babies who die in the first year of life/1000 live births.

• According to the CIA fact book , the USA had an IM rate of 6.37 in 2007. There are 41 countries with better stats than we have.

• http://en.wikipedia.org/wiki/List_of_countries_by_infant_mortality_rate_(2005)

Problems with comparisons• A 2006 article in U.S. News & World Report

states, "First, it's shaky ground to compare U.S. infant mortality with reports from other countries. The United States counts all births as live if they show any sign of life, regardless of prematurity or size. This includes what many other countries report as stillbirths.

• In Austria and Germany, fetal weight must be at least 500 grams (1 pound) to count as a live birth…...

• In Belgium and France, births at less than 26 weeks …. And some countries don't reliably register babies who die within the first 24 hours of birth.

• Thus, the United States is sure to report higher infant mortality rates. For this very reason, the Organization for Economic Cooperation and Development, which collects the European numbers, warns of head-to-head comparisons by country." http://en.wikipedia.org/wiki/Infant_mortality_rate

Newborn morbidity & mortality

• The single most common cause of mortality and morbidity in the newborns in the USA is prematurity.

• Among the 4,058,814 births in the USA in 2000, (11.6%) were born preterm as defined as less than 37 weeks gestational and (1.43%) were VLBW [AGRQ]

• According to the March of Dimes, about 12 percent of babies … are … preterm and of these, 84% are born between 32-36 weeks [risk of HMD] with 10% between 28-31 and only 6% of these less than 28 weeks premature. http://www.musckids.com/health_library/hrpregnant/ptl.htm

risk factors for prematurity include:• Teenage unwed pregnancy. [15 YO &

younger also at high risk of preeclampsia which can lead to eclamsia [Seizures in the mom] the treatment for eclampsia is delivery of the baby.[Merck manual]

• Maternal history of early labor, multiple miscarriages or abortions [ 1 preterm labor increases risk 15%; 2 increases risk 32%. [Czervinske pp.20]

• Multiple births [twins, triplets] vrs singletons [role played by fertility drugs may be significant] According to the U of Washington, Up to 40 % of twins, most triplets and all quadruplets are born prematurely ……In the past 20 years, the number of multiple births has nearly doubled http://uwnews.washington.edu/ni/article.asp?articleID=2995

• Poor prenatal care [see teenaged moms]

The VSBW infant less than 1500 grams:• Prematurity is defined as a

child born before 37 weeks• the VLWB infant is the one

whose birth weight is less than 1500 gram [.68 pounds]

• This category of infants accounts for the highest neonatal mortality and morbidity among newborns, as well as significant tangible and intangible lifelong costs to the family and society for medical care, and ancillary health and educational services. [AGRQ]

• 96% of infants with birth weights between 1251 and 1500 grams survive

• in contrast to 77% of infants with birth weight less than 1250 grams [Stevenson, Wright, Lemons, et al., 1998] [AGRQ]

2nd trimester: Gestation and development

• week # 16 bronchioles are forming

• type I and Type II cells are starting to differentiate

• week 24: Surfactant is starting to be created at week 24

• airways terminate into lung buds, and there are no true alveolar sac and ducts at this time

2nd trimester: Gestation and development

• week 20: capillaries start at the alveolar level, but are still incomplete by 24 weeks.

• Week 26 is the time that true diffusion of gases can occur

• 24th week Diaphragm is fully functional and the baby establishes his FRC with breathing fluid

2nd trimester: Gestation and development

• By 20 weeks, the spinal cord get myelin & baby starts a sleep cycle.

• If he becomes hypoxemic at this point he can respond with increased VE—but chemoreceptors are not dependable

• week 16 lower intestines collect meconium

• 18th week fetus sucks and swallows amniotic fluid

3rd trimester: Gestation and development

• At week 30 the fetus will “practice breathing” is at a RR of 30 bpm

• Surfactant at near normal rates by week 36, so IRDS is rare unless the mom has diabetes

• True alveoli are present• By 28 weeks some regulation of

body functions [nervious system] and by 32 week more reflexes present

• the peripheral chemoreceptors react to lower Pa02 during this time-- but are still unreliable

3rd trimester: Gestation and development

• With alveoli and pulmonary capillaries formed, gas diffusion is complete—will not be as good as adults for quite some time.

• P(A-a)D02 is twice the adults.

conclusions • a 24-week premature infant is

only considered ‘potentially viable,’ many will not make it

• premature infants over 26 weeks have fair mortality with frequent serious lifelong problems

• most 28-week premature infants have excellent prognosis

• premature infants of 36-38 weeks are basically “feeders and growers”.. we feed them and they grow.

• VLBW infants have increased risk of almost all the hazards and complications of premature birth

differences in these children: cardio-pulmonary:

• the normal newborn has relatively ineffective lungs [10x RAW and 1/10th the C]; his VT and IC are so close that his only response to hypercapnia is to increase RR. He cannot afford any limitations to breathing.

• the worse the lung disease, the more likely the baby will suffered from pulmonary HTN that can lead to right heart failure

• the most common cause of PDA is hypoxemia that causes the ductus to re-open

• when the PDA is accompanied by pulmonary HTN the result is persistant fetal circulation-that problem can be fixed only by hyper-oxygenation and respiratory alkalosis

• these increases in mechanical ventilation will increase chances for barotrauma, 02 toxicity and can lead to BPD

differences in these children: nervous system

increased chance of intraventricular hemorrhage [IVH]

delicate blood vessels in the headthis is such a problem that we don’t allow tiny preemies head to go flat much less head down.

Incomplete chemoreceptors that fail to respond can lead to apnea and bradycardia that can quickly result in death; we keep them on monitors

Apnea of prematurity: AOP may need to go home on monitors with parents learning CPR

differences in these children:metabolismto get warm, the preemie uses non-

shivering thermogenesis in which thyroxine and nor-epinephrine trigger metabolism of brown fat which involves accelerated 02 consumption & glucose consumption. the smaller preemies have no

fat stores for insulation and no muscle mass for shivering-both ways we adults conserve heat.

the preemie has increased surface area for heat loss; huge heads

The VLBW infant may not have the brown fat for heat productionThe result is that there is

increased metabolism of 02 to get warm. Cold stress

Is a trigger for hypoxemia & for hypoglycemia

differences in these children:immunities

Sepsis in the VLBW: most congenital/ perinatal infections

result in sepsis because of the unhealed umbilical cord is a conduit for bacterial infections to tract up into the blood steam

The National Epidemiology of Mycosis Study Group reported that over a 2-year period…… 1.2% of all neonates developed candidemia, and of these, 82% were VLBW. [Neely pp. 404]

Because of the problems with heat generation, even the larger preemie may not be able to create enough heat for a fever as a symptom.

A TCH study [10 year review] showed that in the general population of the NICU, .4% were diagnosed with candidal meningitis, but there were 1.1% of the infants under 1500 grams

[almost 3 fold increase]

differences in these children:GI tract/ nutritionNecrotizing enterocolitis [NEC]

decreased blood flow to GI tract results in damage to the tissue and bowel perforation.

Incidence is about 10% of VLBW infants [Pietz]

mortality is about 30% in general population but 66% in VLBW infants [Yeo]

chronic hepatic injury secondary to prolonged TPN

short gut syndrome: complication of severe or multiple NEC

osteomalacia due to poor nutritional support

90% of VLBW infants are in the 10 percentile for growth at 26 weeks and by 18 to 22 months of age 30-40% are still significantly below weight

differences in these children:susceptibility to eye damageRetinopathy of

prematurity ROP: 0ne Indian study found 46% of infants under 1500 grams with varying degrees of ROP. http://www.ncbi.nlm.nih.gov/pubmed/9141799

Blindness due to ROP is directly related to the degree of prematurity and even in the face of improved care, only 20% of treated children will have perfect vision.

differences in these children:pulmonary complicationsIncreased chance of subglottic stenosis

during prolonged intubation & poor outcomes with tracheostomy [committed for entire year]

Time constants and pneumothorax: need to watch inspiratory times

02 and barotrauma lead to Bronchopulmonary dysplasia

BPD: A severe chronic lung disease that results in both obstructive and restrictive defects. 50% in infant under 1000 grams [total BPD in neonatal population is 5-30%]

While more infants survive BPD than die, those with severe BPD who die will succumb to cor pulmonale, pulmonary infections or during exacerbations of the chronic lung disease

differences: neurological increased chances of

IVH, infections, white matter damage and anoxic encephopathy resulting in increased incidences of Cerebral Palsy, blindness, deafness, seizure disorders, and mental retardation.

It is not uncommon to find a child with CP, seizure disorders and profound mental retardation

cost to society The definition of disability in children ….. based on a definition passed by Congress in 1996. Under Title XVI, a child under age 18 years will be considered disabled if he or she has a medically determinable physical or mental impairment or combination of impairments that causes marked and severe functional limitations, and that can be expected to cause death or that has lasted or can be expected to last for a continuous period of not less than 12 months. [AHRQ]

According to the US census of 2000, 11% of the children in the USA have physical or mental disabilities.

cost to society

According to the National Educational Association, the cost of special education is about $16,921 per child and there are 6 million youngsters with a wide array of disabling conditions. [http://www.nea.org/specialed/index.html

American Institution for Research [funded by Department of Education] estimates the cost of special ed at $50 billion for 1999-2000 http://www.nea.org/specialed/index.html

cost to society The emotional costThe perception of most parents of handicapped children and of the population in general is that their divorce rate is high and the remarriage rate is low, but statistics may not support this.

cost to society According to some studies, the divorce rate among parents of handicapped children is at 50% right along with the general population, but that the rate of divorce of very young parents of handicapped eldest child is much higher. Advocacy West Lancs

“In a 1994 study of 8th graders, “families of children with disabilities showed higher percentages of divorce or separation, lower family incomes, and more single-parent households than did the families of the remaining children.” [Hodapp]

Another study of divorce rates …. with Down’s syndrome showed similar numbers to the general population, but did show that of the broken marriages, most of the divorces occurred in the first 1-2 years of the child’s life. [Rosel]

cost to society The emotional costOne UK study of parents of disabled [2-18 year olds] showed that parents may have ‘lost’ aspects of personal identity, feel frustrated with dealing with social and medical services, and got distressed when their child was in physical pain. They wanted their normal children to have positive interactions with the handicapped child. Parents did not want to learn enough of their child care to ‘take over’ from the professionals because they felt a great need for the professional support. http://www.york.ac.uk/inst/spru/pubs/rworks/aug2007-03.pdf

Mothers felt isolated in the home, while the father suffered feeling of exclusion from the child’s care even resentment as the mother tended to get most of the medical information and the professional support while dad was at work. http://www.cafamily.org.uk/fathers.html

New 2005 Guidelines for ALS in the L & D

Infants for whom CPR in the L&D is not indicated:

Birth weight under 400 gram [ gestation less than 23 weeks]

Congenital anomalies incompatible with life or with exceptionally high early mortality such as trisomy 13 & anencephaly

In conditions with anticipated parental burden to the child is high, the parents’ wishes to be supported. [AHI pp. IV-193]

References:

• Neely & Schreiber; Fluconazole Prophylaxis in the Very Low Birth Weight Infant: Not Ready for Prime Time PEDIATRICS Vol. 107 No. 2 February 2001, pp. 404-405

• Fernandez, M, Moylett, EH, Noyola DE and Baker, CJ: Candidal Meningitis in Neonates: A 10Year Review. Clinical Infectious Disease August 2000 http://www.journals.uchicago.edu/doi/full/10.1086/313973?cookieSet=1

• AGRQ: US Agency for Healthcare Research and Quality disability and VLBW http://www.ncbi.nlm.nih.gov/books/bv.fcgi?indexed=google&rid=hstat1a.section.31343

• Yeo, S L; NICU Update: State of the Science of NEC Journal of Perinatal & Neonatal Nursing. 20(1):46-50, January/March 2006.

• Czervinske & Barnhart Perinatal Pediactric Respiratory Care. 2nd edition. 2003 Saunders

• Pietz, J et al J. Prevention of NEC in preterm infant [20-year study] American Accedmeny of Pediatric http://pediatrics.aappublications.org/cgi/reprint/peds.2006-0521v1.pdf

References:

• The Experiences of Fathers of Children with Disabilities, Ruth Soult, Advocacy West Lancs,1998.

• Urbano, R C., Hodapp, R M. Divorce in Families of Children With Down Syndrome: A Population-Based Study American Journal on Mental Retardation Volume: 112 Issue: 4 Pages: 261-274

• 2000 USA census: http://www.census.gov/population/www/socdemo/hh-fam.html

• Hodapp, RM Krasner DFamilies of Children With Disabilities: Findings From a National Sample of Eight-Grade Students Execeptionality 1994 Vol 5, # 2 pp. 71-81.

• Rosel, R, Lawlis GF; Divorce in Families of Genetically handicapped/mentally retarded individuals; American Journal of Family Therapy. Vol 11 # 1 pp. 45-50 Spring 1983.