Preterm infants (prematurity)

1. Preterm infants (prematurity)

2. Definitions: Preterm infant: Is the live born infant delivered before 37 weak from the first day of the last menstrual period. Low birth weight infant(LBW): Is life born infant with birth weight below the 5th percentile of weight for gestational age, they are might be preterm infants or full term infants with intrauterine growth retardation (IUGR) Very low birth weight infant: Is infant with birth weight less than 1500 gm. Extremely low birth weight infant: Is infant with birth weight less than 1000 gm.

3. Causes of prematurity : I. Fetal causes: 1. Fetal distress. 2. Multiple pregnancy. 3. Erythroblastosis fetalis. 4. Non immune hydrops. II. Placental causes: 1. Placental dysfunction. 2. Placenta previa. 3. Abruptio placentae.

4. III. Uterine causes: 1. Bicornate uterus. 2. Cervical incompetence (premature dilation). IV. Maternal causes: 1. Preeclampsia. 2. Chronic medical illnesses (e.g. cyanotic heart diseases, renal diseases). 3. Infection (e.g. group B streptococcus, UTI, bacterial vaginosis, chorioamnionitis) 4. Drugs abuse (e.g. cocaine).

5. V. Others: 1. Premature rapture of membranes. 2. Polyhydramnios. 3. Iatrogenic (poorly timed cesarean section, surgery).

6. Clinical features: 1. Large head compare to the body head. 2. Pink, thin, or transparent skin. 3. Sleepy most of the time (full term baby sleeps about 14 hr/day). 4. Hypotonic with fully extended limbs (frog-like posture). 5. Non palpable breast tissues. 6. Soft pinna of the ear with no cartilage.

7. 7. Undescended testis in the males and widely separated labia in the females. 8. Weak cry, sucking, coughing, and swallowing. 9. Little or no subcutaneous tissues. 10. Excessive lanugo hair (black, soft, and brittle hair over the back and shoulders).

9. Problems of prematurity: 1. Thermal instability: due to: a. Immaturity of heat regulatory center in the brain. b. Poor muscle movements (heat production required active muscle movements). c. Little or no subcutaneous fat. d. Poor sweating mechanism. e. large surface area compared to the body weight. f. Low glycogen stores in their bodies.

10. 2.feeding problems: Preterm infant have incoordinate sucking, swallowing, and breathing (coordination not achieved until 34-36 wks of gestation), so they are liable for aspiration and enteral feeding must be provided by gavage, also the preterm infant frequently have gastro- esophageal reflux and immature gag reflex which increases the risk of aspiration.

11. 3. Respiratory problems: RDS (most common), pneumothorax (either spontaneous or during resuscitation by introducing oxygen pressure more than needed), apnea, bradycardia, and chronic lung disease (bronchopulmonary dysplasia) due to high oxygen concentration usage.

12. 4. Birth asphyxia: The preterm infants are unable to take the 1st breath due to: a. Immaturity of respiratory center in the brain. b. Surfactant deficiency. c. Flail chest of newborn due to thin chest wall and weak intercostal muscles. 5.CVS problems: PDA, bradycardia (with apnea) and congenital malformations.

13. 6. Hematological problems: Anemia (early or late onset), indirect hyperbilirubinemia, bleeding (subcutaneous or internal hemorrhage), vitamin K deficiency. 7. Gastrointestinal problems: Poor motility, necrotizing enterocolitis, direct hyperbilirubinemia, congenital anomalies,gastro-esophageal reflux. 8. Metabolic-endocrine problems: hypocalcemia, hypoglycemia, hyperglycemia.

14. 9. CNS problems: intraventricular hemorrhage, HIE, seizures, retinopathy of prematurity, deafness, hypotonia, kernicterus. 10. Renal problems: hyponatremia, hypernatremia, hyperkalemia, renal tubular acidosis. 11. Infections: Congenital, Perinatal or nosocomial infections. 12. Nutritional problems: Iron, folic acid, phosphorus and vitamin K deficiency.

15. Management of preterm infants: 1. Respiratory support: A. Oxygen therapy: by nasal prong, and if necessary, by Ambu bag or endotracheal intubation. Its should be monitored by pulse oximeter or transcutaneous PaO2 or blood gasses analysis. B. Surfactant therapy for RDS. C. Treatment of apnea of prematurity.

16. 2. Thermal regulation "the most important": Infants should be dried well after birth and put in an overhead radiant heater then transferred to the incubator. 3. Monitoring: By pulse oximeter (put to the ear or fingers) to monitor oxygen saturation, also monitor the pulse rate, respiratory rate, blood gasses and pH and serum electrolytes.

17. 4. CXR: For the diagnosis of respiratory problems (RDS, pneumothorax, emphysema) and to confirm the position of endotracheal tube or umbilical catheter. 5. Treatment of metabolic disturbancesespecially hypoglycemia and hypocalcemia. 6. Minimal handling of the infants: because vigorously handled infant may developed apnea or cardiac arrest.

18. 7. Fluid and nutritional support: The average caloric requirement for the growing premature infant is 120 Kcal/kg/24hr Expected weight gain for the adequately nourished preterm infant is 10-30 gm/day. Initially the preterm infant required 60-70 ml/kg/24hr of 10% dextrose water for the first 24 hr of life to maintain blood glucose concentration between 60-100mg/dl. Then added electrolyte in form of 1/5th glucose saline solution on the second day of life at a rate of 120-150 ml/kg/24hr.

19. Nutritional support for preterm infant started as soon as possible after stabilization of respiration to avoid aspiration by gavage feeding of small volumes of breast milk or 20 kcal/oz of premature formula (10-25% of total infant nutritional need) and slowly advanced to full caloric needs over 3-7 days once the infant is stable.

21. Intermittent bolus gavage feeding is preferable over continuous feeding because is stimulate the release of intestinal hormones and may accelerate the maturation of GIT, but continuous feeding by continuous drip is more safe in extremely LBW infants Nutritional support in VLBW infants is started at 24-48 hr of age with paranteral alimentation solutions given either peripherally or centrally via an umbilical vein. Supplementation of iron, Ca, Ph, folic acid and Vitamin D are usually started after 4-6 wks of life.

22. Parenteral feeding

23. 8. Management of infection: A. Screening for infection: by: a. CBC. b. C-reactive protein. c. WBC count and differential counts. e. Urine examination and culture. f. CSF examination and culture. B. Treatment of any documented infection by appropriate antibiotics therapy.

24. C. Prevention of infection: by: a. Hand washing and health education to the staff. b. Careful cleaning of incubators and all other instruments. c. Avoidance of nosocomial infections by using disposable equipments and isolation of affected infants. d. Antibiotics should be used according to the culture and sensitivity tests. e. Avoid overcrowding and maintain appropriate patient-staff ratio. f. Immunization.

25. Long term complications of prematurity: 1. Chronic lung disease (CLD) or bronchopulmonarydysplasia: 2. Retrolental fibroplasia or retinopathy of prematurity: Its interruption of normal progression of retinal vasculature due to administration of high oxygen concentration for preterm infants. Its responsible for many cases of blindness. So retinal examination should be done at 2-4wks intervals in any premature infant until the retina is fully vascularized. Treatment is by laser therapy

26. 3. Late anemia of prematurity: The Hb level in preterm infant decrease rapidly after birth to reaches its nadir level at 8-12wks of age and is 2-3 g/dl lower than that in term infant. This lower Hb level in preterm infant is due to decreased erythropoietin response to the low RBC mass. Treatment by: 1. Blood transfusion of backed RBC in severe anemia. 2. Erythropoietin 250 Unit/kg given S.C. 3 times/week with iron supplementation in a dose of 4-8mg/kg/day.

27. 4. Necrotizing enterocolitis: It’s the most common acquired G.I. emergency in the newborn infants, its most often affect preterm infants, with an incidence of 10% in infants of birth weight less than 1500g. In term infants its occurs in association with polycythemia, CHD and birth asphyxia. Pathogenesis: is multifactorial interaction between immaturity of GIT ,mucosal injury, and potentially injurious factors in the intestinal lumen like milk protein.

28. Clinical features:abdominal distension (the most common presenting sign), vomiting, bloody stool, abdominal tenderness, temperature instability, apnea, bradycardia, sepsis, decrease COP and poor perfusion. Investigations: 1. CBC shows low Hb concentration, increased WBC count or absolute neutropenia in severe disease and thrombocytopenia. 2. Stress-induced hyperglycemia 3. Metabolic acidosis. 4. Abdominal X-ray (diagnostic) shows presence of air in the bowel wall (pneumatosis intestinalis).

30. Treatment: A. Medical treatment: 1. Decompression of the intestine by N/G. 2. Oxygen supplementation or mechanical ventilation if necessary. 3. IVF and broad spectrum antibiotics. 4. close monitoring of vital signs, physical examination and lab.tests (WBC, platlate, blood gases, and serial abdominal X- rays).

31. B. Surgical treatment:indicated in: 1. Evidence of perforation. 2. Fixed dilated bowel lope on serial X-rays. 3. Abdominal wall cellulitis. 4. Failure of medical treatment. Surgical treatment include resection of necrotic bowel segment and create colostomy, then reanastomosis and closure of colostomy done after resolution of the disease and the infant is growing (usually >2kg body wt after 4-6 wks of age).

32. 5. PDA 6. Rickets. 7. CNS complications: a. Behavioral problems. b. Mental retardation. c. Progressive hydrocephaly. d. Cerebral palsy. e. Learning problems. Thank you for your attention