1 / 161

Chapter 5

Chapter 5. Examination and Assessment of the Neonate. Gestational Age and Size. GA assessment should be done within 12 hours of life for best reliability for infants less than 26 weeks Evaluation of the infant is based on three basic elements: Gestational age Maternal menstrual cycle

kerem
Télécharger la présentation

Chapter 5

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 5 Examination and Assessment of the Neonate

  2. Gestational Age and Size • GA assessment should be done within 12 hours of life for best reliability for infants less than 26 weeks • Evaluation of the infant is based on three basic elements: • Gestational age • Maternal menstrual cycle • Prenatal ultrasound • Postnatal assessment (Ballard Score)

  3. Estimating the Delivery Date Nagele’s Rule • a.   Three months are subtracted from the first day of the last menstrual period, then seven days are added to the result • b.   For example, if the first day of the last menstrual period is May 15, subtracting 3 months would arrive at February 15.  Adding 7 days gives an EDC as February 22 • c.    Requires a regular cycle of 28 days, use of oral contraceptives or irregular cycle reduces the accuracy

  4. Estimating the Delivery Date Fundal Height • a.   Fundus is the portion of the uterus opposite the cervix • b.   The distance from the symphysis pubis and the top of the fundus is measured • c.    The distance in centimeters is equal to the gestational age (20cm = 20 weeks) • d.   Correlates during the first two trimesters

  5. Estimating the Delivery Date Quickening • a.   Sensation of fetal movement • b.   Usually occurs at 16-22 weeks • c.    Very rough estimate of gestational age Determination of Fetal Heartbeat • a.   The fetal heartbeat is heard between 16-20 weeks gestation • b.   As early as 8 weeks with a Doppler device • c.    Rough estimate of gestation age

  6. Prenatal Assessments

  7. Biophysical Tests of Well Being Contraction stress test (CST) • a.   CST assesses fetal response to contractions • b.   Determines the presence of uteroplacental insufficiency • c.    Fetus is stressed during contractions • d.   Positive CST: 50% of contractions have Type II FHR decelerations • e.   Negative CST: no deceleration in FHR • f.     Most tests fall somewhere in between • g.   Can fetus tolerate normal labor and delivery or is Cesarian section needed?

  8. Biophysical Tests of Well Being Contraction stress test (CST) • Variation of CST: Oxytocin Contraction Test (OST) • IV is used to start contractions • Positive CST indicates induction for delivery

  9. Biophysical Tests of Well Being The Non-Stress Test (NST) • a.   The response of FHR to movement is observed • b.   FHR increases 15 bpm > baseline for at lest 15 seconds • c.    Positive NST: at least 2 accelerations over a 20 minute period • d.   Negative NST: no accelerations over a 20 minute period • e.   Fetal monitor is placed on mom’s abdomen; Mom presses a button when the baby moves • f.     Simple to perform, less time consuming, little risk

  10. Biophysical Tests of Well Being Interpretation of CST and NST Positive CST and Negative NST • 1.   Fetus with hypoxia Negative CST and Negative NST • 1.   Fetal sleep • 2.   CNS depression

  11. Biophysical Tests of Well Being Acoustic Stimulation • a.   Buzzer against mom’s abdomen • b.   FHR monitored for accelerations • c.    Failure to accelerate indicates that the fetus is compromised and further testing is required

  12. The Biophysical Profile a.   Fetal breathing b.   Fetal movement c.    Fetal limb tone d.   NST e.   Amniotic fluid volume f.     Normal score is 8-10 g.   May be best overall method of fetal risk determination

  13. Chorionic villus sampling • Form of prenatal diagnosis to determine chromosomal or genetic disorders in the fetus. • It entails sampling of the chorionic villus (placental tissue) and testing it for chromosomal abnormalities, usually with FISH (fluorescence in situ hybridization) or polymerase chain reaction (PCR) • CVS usually takes place at 10–12 weeks' gestation, earlier than amniocentesis or percutaneous umbilical cord blood sampling. It is the preferred technique before 15 weeks

  14. Possible reasons for having a CVS can include: • Abnormal first trimester screen results • Increased nuchal translucency or other abnormal ultrasound findings • Family history of a chromosomal abnormality or other genetic disorder • Parents are known carriers for a genetic disorder • Advanced maternal age (maternal age above 35). AMA is associated with increase risk of Down's syndrome and at age 35, risk is 1:400. • Screening test are usually carried out first before deciding if CVS should be done.

  15. Amniocentesis • used in prenatal diagnosis of chromosomal abnormalities and fetal infections • a small amount of amniotic fluid, which contains fetal tissues, is sampled from the amnion or amniotic sac surrounding a developing fetus, and the fetal DNA is examined for genetic abnormalities.

  16. Amniocentesis tests • L/S Ratio and presence of PG • Alpha-Fetoprotein (AFP): increased in neural tube defects, decreased in Down’s Syndrome and in fetal death • Bilirubin: hemolytic disease such as Rh incompatibility • Creatinine Levels: determine fetal kidney maturity • Meconium Staining: green fluid (normally clear) • Cytology: cells from skin, amnion, TB tree, detect genetic and chromosomal disorders; cultured and grown; takes two weeks for results

  17. Amniocentesis • Amniocentesis can also be used to detect problems such as: • Infection, in which amniocentesis can detect a decreased glucose level, a Gram stain showing bacteria or an abnormal differential count of white blood cells • Rh incompatibility • Decompression of polyhydramnios

  18. Genetic diagnosis • Early in pregnancy, amniocentesis used for diagnosis of chromosomal and other fetal problems such as: • Down syndrome (trisomy 21) • Trisomy 13 • Trisomy 18 • Fragile X • Rare, inherited metabolic disorders • Neural tube defects (anencephaly and spina bifida) by alpha-fetoprotein levels.

  19. Trisomy 13 (Patau Syndrome) • Some or all of the cells of the body contain extra genetic material from chromosome 13. • Full trisomy 13 is caused by nondisjunction of chromosomes during meiosis (the mosaic form is caused by nondisjunction during mitosis) • Disrupts the normal course of development, causing severe heart and kidney defects • risk of this syndrome in the offspring increases with maternal age at pregnancy, with about 31 years being the average.[ • Patau syndrome affects somewhere between 1 in 10,000 and 1 in 21,700 live births

  20. Trisomy 18 (Edwards Syndrome) • Presence of all or part of an extra 18th chromosome. This genetic condition almost always results from nondisjunction during meiosis. • It is the second most common autosomal trisomy, after Down's syndrome, that carries to term. • Edwards syndrome occurs in around one in 6,000 live births and around 80 percent of those affected are female. • The majority of fetuses with the syndrome die before birth. • The incidence increases as the mother's age increases. The syndrome has a very low rate of survival, resulting from heart abnormalities, kidney malformations, and other internal organ disorders.

  21. Fragile X syndrome (FXS), Martin–Bell syndrome, or Escalante's syndrome • genetic syndrome that is the most widespread single-gene cause of autism and inherited cause of mental retardation among boys. • It results in a spectrum of intellectual disabilities ranging from mild to severe as well as physical characteristics such as an elongated face, large or protruding ears, and large testes (macroorchidism), and behavioral characteristics such as stereotypic movements (e.g. hand-flapping), and social anxiety.

  22. Amniocentesis and lung maturity • fetal lung maturity, which is inversely correlated to the risk of infant respiratory distress syndrome. • In pregnancies of greater than 30 weeks, the fetal lung maturity may be tested by sampling the amount of surfactant in the amniotic fluid. • lecithin-sphingomyelin ratio ("L/S ratio"), the presence of phosphatidylglycerol (PG), and more recently, the surfactant/albumin (S/A) ratio. For the L/S ratio, if the result is less than 2:1, the fetal lungs may be surfactant deficient. The presence of PG usually indicates fetal lung maturity. For the S/A ratio, the result is given as mg of surfactant per gm of protein. An S/A ratio <35 indicates immature lungs, between 35-55 is indeterminate, and >55 indicates mature surfactant production(correlates with an L/S ratio of 2.2 or greater).

  23. Prenatal Ultrasound • There are several types of fetal ultrasound, each with specific advantages in certain situations. A Doppler ultrasound, for example, helps to study the movement of blood through the umbilical cord between the fetus and placenta. Three-dimensional ultrasound provides a life-like image of an unborn baby.

  24. Clinical applications • Identification of pregnancy • Identification of multiple fetuses • Determination of fetal age, growth and maturity • Observation of polyhydramnios and oligohydramnios • Detection of fetal anomalies • Determination of placenta previa • Identification of placental abnormalities • Location of the placenta and fetus for amniocentesis • Determination of fetal position • Determination of fetal death •  Examination of fetal heart rate and respiratory effort • Detection of incomplete miscarriages and ectopic pregnancies

  25. Prenatal Ultrasound • Ultrasound uses an electronic device called a transducer to send and receive sound waves. When the transducer is moved over the abdomen, the ultrasonic sound waves then move through the skin, muscle, bone, and fluids at different speeds. The sound waves bounce off the fetus like an echo, returning to the transducer. The transducer picks up the reflected waves and converts them into an electronic picture. • A clear gel is placed between the transducer and the skin to allow for the best sound conduction and smooth movement of the transducer.

  26. Prenatal Ultrasound • Certain fetal structures are checked during routine ultrasonography. • Head and brain. The chambers within the brain (ventricles), distance between parietal bones of the fetal head (biparietal diameter), and skin thickness at the back of head (nuchal area) are evaluated for defects. • Heart. The chambers and valves of the heart are evaluated and defects may be identified. • Abdomen and stomach. The size, location, and arrangement of stomach and diaphragm are checked. • Urinary bladder. The size and presence of the bladder is evaluated. • Spine. Defects may be identified if present. • Umbilical cord. Three blood vessels should be attached at the front of the abdomen. • Kidneys. Two kidneys should be present on either side of the mid-spine. • Other fetal structures. Limbs and other parts may also be scanned and evaluated. • http://www.baby2see.com/medical/charts.html#Measurement_Standards_Chart

  27. Gestational age is usually determined by the date of the woman's last menstrual period, and assuming ovulation occurred on day fourteen of the menstrual cycle. • Sometimes a woman may be uncertain of the date of her last menstrual period • Ultrasound scans offer an alternative method of estimating gestational age. The most accurate measurement for dating is the crown-rump length of the fetus, which can be done between 7 and 13 weeks of gestation. After 13 weeks of gestation, the fetal age may be estimated using the biparietal diameter (the transverse diameter of the head), the head circumference, the length of the femur, the crown-heel length (head to heel), and other fetal parameters.[ • Dating is more accurate when done earlier in the pregnancy; if a later scan gives a different estimate of gestational age, the estimated age is not normally changed but rather it is assumed the fetus is not growing at the expected rate

  28. Alpha-Fetal Protein • a proteinthat in humans is encoded by the AFP gene • The AFP gene is located on the q arm of chromosome 4 • AFP is a major plasma protein produced by the yolk sac and the liver during fetal development that is thought to be the fetal form of serum albumin.

  29. Alpha-Fetal Protein • In pregnant women, fetal AFP levels can be monitored in urine. AFP is cleared strongly from the kidneys allowing AFP to tend to mirror fetal serum levels. • In contrast, maternal serum AFP levels are much lower but continue to rise until about week 32. This is thought to be because the mother is not utilizing the AFP, and therefore clears it from her system without issue.

  30. Alpha-Fetal Protein • AFP in amniotic fluid has one or two sources. The fetus normally excretes AFP into its urine, hence into the amniotic fluid. A fetus with one of three broad categories of defects also releases AFP by other means. These categories are open neural tube defect, open abdominal wall defect, and skin disease or other failure of the interior or exterior body surface. • Abnormally elevated AFP in amniotic fluid can have one or more of many different causes: • normal elevation. 75% of AF AFP test results in the range 2.0 to 4.9 MoM are false positives: the baby is normal. • open neural tube defect • open abdominal wall defect • congenital nephrosis

  31. Neural tube defects • one of the most common birth defects, occurring in approximately one in 1,000 live births in the United States. • A NTD is an opening in the spinal cord or brain that occurs very early in human development. In the 3rd week of pregnancy called gastrulation, specialized cells on the dorsal side of the fetus begin to fuse and form the neural tube. When the neural tube does not close completely, an NTD develops

  32. Neural tube defects • Anencephaly (without brain) is a neural tube defect that occurs when the head end of the neural tube fails to close, usually during the 23rd and 26th days of pregnancy, resulting in an absence of a major portion of the brain and skull. Infants born with this condition are born without the main part of the forebrain-the largest part of the cerebrum. Infants born with this condition are usually blind, deaf and unconscious. The lack of a functioning cerebrum will ensure that the infant will never gain consciousness. Infants are either stillborn or usually die within a few hours or days after birth. • Encephaloceles are characterized by protrusions of the brain through the skull that are sac-like and covered with membrane. They can be a groove down the middle of the upper part of the skull, between the forehead and nose, or the back of the skull. Encephaloceles are often obvious and diagnosed immediately. Sometimes small encephaloceles in the nasal and forehead are undetected. • Hydranencephaly is a condition in which the cerebral hemispheres are missing and instead filled with sacs of cerebrospinal fluid.

  33. Cordocentesis • a.   In utero sampling of fetal umbilical cord blood • b.   Under ultrasound, the umbilical cord is punctured with a 22 gauge needle and blood samples are drawn into tuberculin syringes • c.    Samples checked for sickle-cell, hemophilia, fetal infection, metabolic disease, congenital defects, PO2 and acid-base status • d.   Fetal and maternal risk is < 1%

  34. Maternal Estriol • Secreted in high quantities by the placenta in the latter half of pregnancy • Normal levels depend on properly functioning fetal liver and adrenal glands • Levels are decreased in growth retardation, fetal distress, and placental insufficiency • Maternal blood and /or urine is collected several times a week • Fetal distress is indicated by a 50-60%  drop from previous tests or ongoing drop • Inconvenient, high number of false negatives

  35. Human Placental Lactogen (HPL) • Produced by the placenta, excreted in maternal blood • Prepares breasts for milk production • Levels increase until 37 weeks then remains same or decreases slightly • Serum levels are evaluated weekly • Normal range (term) 5.4-7.0 ug/mL • HPL< 4 ug/mL after 30 weeks gestation may indicate fetal compromise • Less popular in recent years, inconvenient

  36. MRI in assessing fetal status • Used to assess the status of soft tissue structure and function • Indicated when ultrasound is insufficient • Used to detect placental and fetal abnormalities • Assess development of the fetal lungs and brain • No risk of damage to the fetus

  37. Meconium Staining • Assessed during amniocentesis or through fluid discharge before delivery • Treat with Amnioinfusion, a method of thinning thick meconium that has passed into the amniotic fluid through pumping of sterile fluid into the amniotic fluid, has not shown a benefit in treating MAS

  38. Assessing Fetal Heart Rate • Purpose correlates with fetal well-being • Three ways to monitor FHR i.      Doppler transducer on mom’s abdomen ii.      ECG monitor on mom’s abdomen iii.      Small electrode on fetal scalp; membranes are ruptured so there is a risk of infection

  39. Assessing Fetal Heart Rate • Normal range is 120 to 160 bpm • An increase or decrease of 20 to 30 bpm may be abnormal even if in normal range • Variability: Fetus has a constantly changing heart rate (5-10 bpm) • Decreased variability is caused by: a.   CNS depression secondary to hypoxia b.   fetal sleep c.    immaturity d.   maternal narcotic use

  40. Bradycardia • Heart rate < 100 bpm or a drop of 20 bpm from baseline Causes a.   Fetal asphyxia i.      most dangerous cause ii.      treat by giving mom O2 b.   congenital heart defects c.    hypothermia

More Related