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Neonatal Emergencies

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  1. Neonatal Emergencies Joy Loy MD March 2009

  2. Objectives Participants will be able to • discuss the underlying pathophysiology of selected neonatal emergencies, • explain the anesthetic implications and • describe safe anesthetic plans for each.

  3. Preoperative Evaluation • Maternal and perinatal history • Recreational drug use • Birth history • Minimum labs: glucose and CBC • Look for associated anomalies • Cardiac and respiratory status • Metabolic and electrolyte imbalance • Hydration status • Coagulation profile • IV access

  4. Pyloric Stenosis

  5. Pyloric Stenosis Most common GI obstructive anomaly in neonates Hypertrophy of the muscular layer of the pylorus A medical emergency but not a true surgical emergency Incidence: 1 – 3 :1,000 live births 2 - 5x more common in first born, M > F (4:1)

  6. Pyloric Stenosis Etiology : unknown ? acquired condition with hereditary predisposition Symptoms are apparent between 2nd-6th wk of life Presents with nonbilious projectile vomiting, signs of dehydration, jaundice (2%)

  7. Pyloric Stenosis Physical Exam visible gastric peristalsis palpable “olive-shaped” mass to the right of the epigastric area signs of dehydration Labs: CBC serum electrolytes EKG ABG BUN

  8. Pyloric Stenosis Diagnosis history and physical exam abdominal ultrasound upper GI series with barium contrast not recommended pathological pyloric wall thickness ≥ 4 mm pyloric length of > 16 cm

  9. Pyloric Stenosis • Metabolic Abnormalities • hyponatremia • hypochloremia • hypokalemia • 1° metabolic alkalosis • compensatory respiratory acidosis • paradoxical acidic urine

  10. Pyloric Stenosis Preoperative Preparation supportive treatment surgical management check lab indices for safe anesthesia

  11. Pyloric StenosisPreoperative Preparation Supportive therapy • Correction of fluid deficits maintenance: D5 0.2% NaCl + KCl 20 - 40 mEq/L replacement: LR, albumin, normal saline • Correction of electrolyte imbalance • Prevention of aspiration : NGT

  12. Pyloric Stenosis Surgical Management Pyloromyotomy definitive treatment open or laparoscopic Lab indices for safe anesthesia serum Cl >100 mEq/L HCO3 < 28 mEq/L

  13. Pyloric Stenosis • Anesthetic Concerns • pulmonary aspiration • severe dehydration • metabolic alkalosis

  14. Pyloric StenosisIntraoperative Management Monitors : ASA standard Decompress the stomach GA: Induction: controversial awake intubation rapid sequence IV induction and intubation with cricoid pressure inhalation induction with cricoid pressure ± muscle relaxant

  15. Pyloric StenosisIntraoperative Management • Cook-Sather, 1998 (CHOP) • prospective, nonrandomized study • awake vs paralyzed intubation (RSI and MRSI) • faster and more successful tracheal intubation with muscle paralysis • awake intubation does not protect from bradycardia and desaturation

  16. Pyloric StenosisIntraoperativeManagement Maintenance IV narcotics: rarely needed inhalational agents Postop pain relief acetaminophen 30-40 mg/kg PR caudal epidural LA infiltration of surgical incision

  17. Pyloric Stenosis Extubate awake Postoperative concerns respiratory depression and apnea hypoglycemia

  18. Congenital Diaphragmatic Hernia a problem unresolved

  19. Congenital Diaphragmatic Hernia Herniation of abdominal viscera into the thorax Result from failure of the pleuroperitoneal canal to close at ~ 8th wk of gestation or early return of midgut to the peritoneal cavity Most challenging and frustrating of all neonatal surgical emergencies

  20. Congenital Diaphragmatic Hernia 50% mortality regardless of the method of treatment Incidence: 1:2,000-5,000 live births M<F 1:1.8, frequently full term Etiology: unknown no genetic factors have been implicated Antenatal history: polyhydramnios

  21. Congenital Diaphragmatic Hernia • Classification • Absent diaphragm : rare • Diaphragmatic hernia • 80% posterolateral L >R (Bochdalek) • 2% anterior (Morgagni) • 15 - 20% paraesophageal • Eventration (15 - 20%)

  22. Congenital Diaphragmatic Hernia • Associated anomalies (20-50%) • cardiovascular 13 - 23% • CNS 28% • gastrointestinal 20% • genitourinary 15% • increase the mortality rate

  23. Congenital Diaphragmatic Hernia • Classic Triad • Dyspnea • Cyanosis • Apparent dextrocardia

  24. Congenital Diaphragmatic Hernia Physical Exam scaphoid abdomen and barrel chest bowel sounds in the chest displaced heart sounds Laboratory Studies CBC ABG electrolytes calcium glucose

  25. Congenital Diaphragmatic Hernia • Diagnosis: chest x-ray • loops of bowel in the chest • mediastinal shift • absent lung markings

  26. Congenital Diaphragmatic Hernia IMMEDIATE Intubation + Stomach Decompression

  27. Congenital Diaphragmatic Hernia Determinants of Survival • degree of pulmonary hypoplasia ipsilateral lung > contralateral lung • development pulmonary vasculature

  28. Congenital Diaphragmatic Hernia • Goals of Management • maximize arterial oxygenation • mechanical ventilation: use low inflating • pressures • increases pulmonary blood flow • prevention of pain • fentanyl infusion 3-10 mcg/kg/hr • correction of acidosis

  29. Congenital Diaphragmatic Hernia Standard Management Strategy Reduce pulmonary HTN Moderate alkalosis pCO2 < 40 mmHg PaO2 >100 mmHg

  30. Congenital Diaphragmatic Hernia • Recent Strategy • Permissive hypercapnia and hypoxemia • Pressure-limited ventilation (<25 cmH2O) • Postductal pCO2 40-65 mmHg • Preductal SpO2 85-90% • Postductal SpO2 ignored unless pH is • < 7.20 or pCO2 > 65

  31. Congenital Diaphragmatic Hernia Bohn (1986) reevaluation of the traditional “mad dash” surgical strategy recommended 24 – 48 hrs medical stabilization assessment of efficacy of delayed approach infants unresponsive to initial therapy will fail to survive with surgery or any other treatment including ECMO

  32. Congenital Diaphragmatic Hernia • The Relationship Between PaCO2 and Ventilation Parameters in Predicting Survival in CHD • Arterial CO2 accurately reflects the degree of lung development • Poor survival in the presence of severe pulmonary hypoplasia • CO2 retention and severe preductal shunting have 90% mortality • Bohn, DJ, et al J of Pedia Surg 19: 666-671, 1884

  33. Congenital Diaphragmatic Hernia nomogram: to predict the degree of pulmonary hypoplasia in the infants and chance of survival used the preop PaCO2 and an index of ventilation (Vi) If PaCO2< 40 and Vi < 1000: survival almost universal If PaCO2> 40 and Vi > 1000: death virtually inevitable ٭Vi = mean airway pressure x respiratory rate

  34. Congenital Diaphragmatic Hernia Relationship of Alveolar-arterial Oxygen Tension Difference in Diaphragmatic Hernia in the Newborn A-aDO2 on 100% O2 < 400 mmHg: usually survive 400 - 500 mmHg: intermediate chance > 500 mmHg: unlikely to survive Harrington J, et al Anesthesiology 56: 473-476, 1982

  35. Congenital Diaphragmatic Hernia Acid Base Balance and Blood Gases in Prognosis and Therapy of CHD High Mortality pH < 7.0 pCO2 >60 mmHg pO2 < 50 mmHg Boix-Ochoa J, et al J Pediatric Surg 9:49-57, 1974

  36. Congenital Diaphragmatic Hernia • Indications of Surgical Repair • Reversal of ductal shunting • O2 index of < 40 • Arterial pCO2 maintainable under • 40 mmHg • Hemodynamic stability

  37. Congenital Diaphragmatic HerniaPreoperative Preparation • Look for associated anomalies • Labs: CBC, electrolytes, ABG, glucose, blood type and crossmatch • Ancillary procedures: CXR, Echo • Venous access: upper extremities preferred • Prevention of hypothermia

  38. Congenital Diaphragmatic HerniaIntraoperative Management Monitors: ASA standard invasive : arterial line ± CVP foley catheter * 2 pulse oximeters: preductal and postductal * precordial stethoscope on the right axilla NGT to decompress the stomach Adequate IV access

  39. Congenital Diaphragmatic HerniaIntraoperative Management Induction awake intubation rapid sequence IV induction and intubation with assisted or controlled ventilation * avoid mask ventilation or PPV before intubation Supine position, left subcostal incision

  40. Congenital Diaphragmatic HerniaIntraoperative Maintenance of anesthesia volatile agents + IV narcotics + muscle relaxants TIVA avoid nitrous oxide avoid increase in PVR leading to R→L shunting: hypoxia, acidosis, hypothermia, pain treat metabolic acidosis replace significant blood loss

  41. Congenital Diaphragmatic HerniaIntraoperative Mechanical Ventilation adjust FiO2 to achieve PaO2 80 -100 mmHg SpO2 95 - 98% small tidal volume to keep airway pressure < 20-30 cm H2O high respiratory rate 60-120 /min to PaCO2 25-30 mm Hg

  42. Congenital Diaphragmatic HerniaIntraoperative Surgical repair primary closure staged procedure Transabdominal subcostal incision Thoracoscopic repair has been reported

  43. Congenital Diaphragmatic HerniaIntraoperative • Potential Problems • Hypoxemia • distension of stomach • 1° pulmonary hypoplasia / pulmonary HTN • Contralateral pneumothorax • Hypotension or IVC compression • Cardiac arrest

  44. Congenital Diaphragmatic Hernia • Postoperative Care • Ventilatory support • Close fluid management • Hemodynamic monitoring • “Honeymoon Period” followed by deterioration • increase abdominal pressure • impaired peripheral and visceral perfusion • limited diaphragmatic excursion • worsening of pulmonary compliance

  45. Congenital Diaphragmatic Hernia • Management of PPHN • Minimize ETT suctioning • Vasodilators : rarely effective • tolazoline isoproterenol PGE1 • nitroglycerin SNP • Inhaled nitric oxide • endothelium - derived relaxing factor (EDRF) • selective pulmonary vasodilation • rapidly metabolized • has not been shown to improve survival

  46. Congenital Diaphragmatic Hernia Extracorporeal Membrane Oxygenation (ECMO) • Use: controversial • Allows the lungs to develop & restructure • Expensive • improved survival in neonates with • > 80% mortality

  47. Congenital Diaphragmatic Hernia • Criteria for ECMO • Gestational age ≥ 34 wks • Reversible disease process present • Weight ≥ 2000 grams • Predicted mortality ≥ 80% • estimated by oxygenation index of > 40 • FiO2 x mean airway pressure x 100 • PaO2

  48. Congenital Diaphragmatic Hernia Contraindications Gestational age < 34 wks Weight < 2000 grams Preexisting intracranial hemorrhage (≥ grade II) Aggressive respiratory treatment > 1 wk Congenital heart disease Congenital or neurological abnormality incompatible with good outcome

  49. TracheoEsophageal Fistula (TEF)

  50. Tracheoesophageal Fistula Incidence: 1:4000 live births M > F (25:3) 10-40% are preterm Antenatal history: polyhydramnios (60%) Etiology: failure in mesenchymal separation of upper foregut