1. Respiratory Distress Syndrome IAP UG Teaching slides 2015-16 1

2. What the Medical student or primary care physician should know Purpose: Simple intervention CPAP can save many preterm babies with moderately severe RDS Surfactant therapy – cost effective / life saving ANS – prevention of RDS Detailed – skill to be acquired ANS RD scores Basic knowledge IAP UG Teaching slides 2015-16 2

3. Respiratory Distress Syndrome Respiratory distress due to ↓surfactant Most common cause of RD in premature PRIMARY - Prematurity Genetic SECONDARY - Meconium Aspiration Lung insult-Asphyxia IAP UG Teaching slides 2015-16 3

4. RDS / HMD Preterm, GA 28 – 32 wk <28wk GA 60-80% 32-36wk GA 15-30% 37wk-term Predisposing factors – Prematurity Birth Asphyxia LSCS Male sex Maternal Diabetes Rh Negative IAP UG Teaching slides 2015-16 4

5. Pathogenesis ↓ Surfactant Alveolar Atelectasis Hyaline Membrane Formation Fibrinous Exudates Interstitial Edema ↓ Lung Compliance IAP UG Teaching slides 2015-16 5

6. Pathogenesis - Transient Tachypnea - Asphyxia - Hypothermia - Apnea ↓ pH, ↓ PO2, ↑ PCO2 ↓ Surfactant RDS Prematurity - Familial Predisposition - C-Section Alveolar Hypoperfusion RL Shunt Pulm. Vasoconstr. ShockHypovolemia Atelectasis IAP UG Teaching slides 2015-16 6

7. Clinical Features Usually a Preterm Baby Respiratory Distress within 6 hrs of Life (usually within minutes of birth) SCR, ICR, Grunting, Cyanosis, Ala nasi Flaring*. Auscultation: ↓ air entry ± fine rales Apnea in extreme prematurity Shock Other features: Edema, ileus, & oliguria IAP UG Teaching slides 2015-16 7

8. Clinical Course Severe cases develop respiratory failure needing ventilation / surfactant / CPAP – and may tire and develop apnea / die if care not offered Mild cases – can be managed with only oxygen Symptoms progress to peak in 3 days Improvement thereafter (often heralded by spontaneous diuresis) IAP UG Teaching slides 2015-16 8

9. Differential Diagnosis Early onset sepsis / congenital Pneumonia TTNB CHD (TAPVC) IAP UG Teaching slides 2015-16 9

10. Investigations Amniotic fluid – Lecithin to Sphingomyelin ratio (L/S) ratio >2.5 = 0.5%, >2 =10%, 1.5-2 = 15-20%, <1.5 = 60% risk of developing RDS Blood & Meconium depress mature L/S ratio and may elevate immature ratio Exceptions : IDM, Asphyxia- can develop RDS even if ratio ok Phosphatidylglycerol = present Saturated Phosphatidylcholine (SPC) > 500 ug/dl IAP UG Teaching slides 2015-16 10

11. Investigations – Cont... Gastric Aspirate – Shake Test Mix 0.5 ml of gastric aspirate & 0.5 ml of absolute alcohol Shake for 15 seconds & allow the solution to settle for 15 seconds If no bubbles – 60 % chances of RDS Small bubbles to the extent of 1/3 rd of the circle of the test tube – 20% chances of RDS All around the circle – bubbles in two circle in some places – bubbles in two row & above <1% chances of RDS IAP UG Teaching slides 2015-16 11

12. Investigations (cont…) Lamellar body counts (phospholipid “packages” produced by type2 alveolar cells) in amniotic fluid >50,000 lamellar bodies/μL → lung maturity IAP UG Teaching slides 2015-16 12

13. Investigations - Contd.. X-Ray Chest: Reticulo granular pattern Air bronchogram Ground Glass opacity White wash appearance in severe RDS IAP UG Teaching slides 2015-16 13

14. X-Ray - RDS IAP UG Teaching slides 2015-16 14

15. Investigations – Cont... Related to Acute Care & DD Blood Gases – hypoxia and hypercarbia Echo – for associated PDA / exclude CHD Supportive care Cranial Ultra sonography Blood Chemistry Sepsis Screening IAP UG Teaching slides 2015-16 15

16. PREVENTION Induction of labour should preferably be delayed till lung maturity Prevent fetal asphyxia by antenatal & intranatal monitoring Antenatal Steroids (to Mother) Betamethasone 12mg IM 2 doses in 24 hrs interval (preferred) Dexamethasone 4 doses in 12 hrs interval IAP UG Teaching slides 2015-16 16

17. Antenatal steroids Must be given to all mothers in preterm labor (<37 weeks) Decreases incidence of severe RDS, IVH, mortality by half Can be given even if mother has HTN, diabetes IAP UG Teaching slides 2015-16 17

18. Treatment SPECIFIC – Surfactant Therapy Types of surfactants: Natural – Bovine, Calf, Porcine Synthetic Timing of intervention: Prophylaxis (before onset of RD) RD) Treatment (rescue – after onset of RD) IAP UG Teaching slides 2015-16 18

19. Surfactant therapy Given in to trachea Produces immediate improvement in lung condition Relatively costly drug No serious side effects in immediate period / long term IAP UG Teaching slides 2015-16 19

20. Supportive Rx Ventilatory Support - CPAP & Positive pressure ventilation Maintain PaO 2 50-80 mm Hg (SpO 2 85-95%) Maintain PaCO 2 45-55 mm Hg O 2 should be warm, humidified, & delivered by a blender Monitor O 2 by concentration IAP UG Teaching slides 2015-16 20

21. Supportive Rx (Cont…) Shock – Fluids, inotropes Temperature Control Nutrition – TPN Sepsis Rx – Antibiotics till infection is ruled out Developmental friendly nursing policy IAP UG Teaching slides 2015-16 21

22. Complications Air leaks - Pneumothorax, Pneumomediastinum, PIE, Pneumopericardium, Air Embolism PDA – look for & treat aggressively Infection – especially Nosocomial Intracranial hemorrhage – monitor USG Feed intolerance IAP UG Teaching slides 2015-16 22

23. Outcome in the Survivors Survival rates near 100 % with CPAP / ventilation and surfactant in babies > 28 weeks / 1000 gms No increased respiratory morbidity in future except in extreme preterm In ELBW Bronchopulmonary dysplasia (BPD) (dependant on oxygen or respiratory support for prolonged period) 5-30% Co-existing morbidities in very preterm Retinopathy of prematurity (ROP) of <1250 g 7% Neurologic impairment – related to PVL, IVH, prematurity 10- 15% IAP UG Teaching slides 2015-16 3

24. RD score 12 RR60-80>80 RetractionsNoneMild- modSevere GruntingNoneAudible by steth Audible without steth Breath soundsGoodDecreasedVery poor SaturationWithout oxygen With < 40 % oxygen High oxygen need IAP UG Teaching slides 2015-16 24

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