Neonatal Intraabdominal Surgery PDF

Neonatal Intraabdominal Surgery  Tracheoesophageal fistula Congenital Outline diaphragmatic hernia Pyloric stenosis Tracheoesophageal fistula & esophageal atresia  Incidence 1:3000 live births Pathophysiology Tracheo...

Neonatal Intraabdominal Surgery  Tracheoesophageal fistula Congenital Outline diaphragmatic hernia Pyloric stenosis Tracheoesophageal fistula & esophageal atresia  Incidence 1:3000 live births Pathophysiology Tracheoesophageal fistula Inhaled air bypass the lungs through fistula into the stomach  hypoventilation and stomach distension Risk of acidic stomach content refluxing via fistula back into trachea  aspiration pneumonitis Esophageal atresia Pooling of secretions from hypopharynx in proximal portion  drooling, coughing, choking with feeds  Development of foregut At fourth to fifth weeks of embryonic development (A) The laryngotracheal diverticulum forms as a ventral outpouching from the caudal part of the primitive pharynx. (B) Tracheoesophageal folds begin to fuse toward the midline to eventually form the tracheoesophageal septum. (C) The tracheoesophageal septum has completely formed. (D) If the tracheoesophageal septum deviates posteriorly, oesophageal atresia with a tracheoesophageal fistula develops  Type A : EA without fistula (7.7%) Gross’s Type B : EA with proximal fistula (0.8%) classification Type C : EA with distal fistula (86%) - commonest Type D : EA with proximal and distal fistula (0.7%) Type E : Tracheoesophageal fistula without atresia (4.2%)  Associated anomalies VACTERL association (50% of TEF/EA) – 3 or more of the lesions: Vertebral defects (10%) Anal atresia (14%) Cardiac anomalies (29%) ie VSD, ASD, TOF, PDA Tracheo-Esophageal fistula Renal dysplasia, hydronephrosis, ureteral malformation, hypospadias Limb defects ie radial aplasia Others : Malrotation of midgut, duodenal atresia  Genetic abnormalities Trisomy 13 (Patau), 18 (Edward), 21 (Down) CHARGE syndrome Feingold syndrome Pallister- Hall syndrome Anophthalmia- esophogeal- genital (AEG)syndro me Presentations Polyhydramnios during pregnancy Failure to pass OG tube  Coiled tube in upper esophageal pouch Excessive pharyngeal secretions/ copious drooling 3Cs  choking, coughing, cyanosis during first feeding attempt Pneumonia/pneumonitis may be present Absence of fluid-filled stomach bubble on prenatal ultrasound  Group 1: weight Okamot >2kg, no major cardiac disease, o et al survival 100% Group 2 : weight 2kg, major cardiac disease, survival ed 72% Group 4 : weight 1unit Pack cell  NBM status Warm isolette (incubator) Head elevated 30degree Preoperativ Replogle tube in upper pouch e Intermittent lower pressure suction applied to one lumen Evaluation Second lumen entrains air to prevent obstruction & Hydration Acid base balance, electrolytes, Preparation glucose Treat pneumonia (antibiotics) Not intubated routinely to minimize gastric distension from PPV unless severe pulmonary disease  Very early primary repair - standard of care If severe pneumonia or respiratory distress, need for intubation Timing of HFOV able to optimize ventilation with minimum peak inspiratory pressure while surgery minimizing gastric distension If insufficient, gastrostomy may allow drainage of gastric fluid and prevent gastric distension If fail to ventilate adequately, to proceed with emergency occlusion or ligation of fistula  Monitoring : temperature, SpO2, ECG, EtCO2, BP IV Access : arterial line, 2 peripheral Intraoperati lines, central line Suction replogle tube before induction ve Dextrose-containing solution at a manageme controlled-rate to avoid hypoglycemia (ie D10/0.2 NS) nt Insensible losses 3-4ml/kg/hr replaced with isotonic solution Urine output 1ml/kg/hr  Transport to OT in warm isolette Surgical irrigation, IV crystalloid and Intraoperati blood products should be warmed ve Forced-air convective warming system Appropriate size HME manageme Neonate prone to hypothermia, limited nt subcutaneous fat Compensate with brown fat non-shivering thermogenesis  Goal: allow adequate gas exchange with lowest inspiratory pressure needed to inflate the lungs, minimize atelectasis and minimize gas flow through fistula. Intravenous induction with RSI and intubation  minimize face mask ventilation Options Deep inhalational induction, gentle PPV and for intubation induction Gentle assisted or controlled ventilation is preferred Keep low peak pressure, high rate  Induction Correct positioning of ETT Identify level of fistula  allow Goal: tip of ETT distal to correct position of ETT fistula, yet proximal to carina Presence of tracheomalacia If in good position, can be and second fistula paralysed and PPV maintained Occlusion of fistula by Keep tip of ETT above fistula 3.5Fogarty occlusion catheter with low ventilation pressure  allowing normal PPV until fistula is ligated  minimize risk of ETT malposition Role of bronchoscopy  Depends on distance between upper and lower portions of esophagus Options: Primary anastomosis and ligation of fistula Feeding gastrostomy and cervical oesophagostomy until definitive surgery later Thoracotomy approach Surgical Left lateral position with right side up Extrapleural approach  minimize danger of procedure anastomotic leak Thoracoscopic surgery Arterial line is required due to significant gradient between EtCO2 and PaCO2 Not requiring lung isolation Expect sudden desaturation requiring high FiO2, and sudden increase in EtCO2 if OLV is required  Hypoventilati on  Hypothermi hypercarbia, Common a atelectasis, desaturation intraoperat Gastric ETT kinking ive distension requiring gastric or displacement to problems decompressio n endobronchia l/ fistula Blood and secretions  blocked ETT  Analgesia Fentanyl 1-2mcg/kg Caudal epidural catheter threaded up to thoracic region Postoperati Keep intubated in NICU ve care If aspiration pneumonia or lung disease from prematurity, low birth weight, premature, receiving narcotics for pain, risk of tracheomalacia (deficiency of tracheal cartilage at the level of fistula) Care to limit inspiratory pressure to protect the repair from  Anastomotic leak (15%) – requiring immediate exploration Esophageal dysmotility – vagal nerve injury GERD Esophageal stricture – requiring repeated dilatations Tracheomalacia Complications  Congenital diaphragmatic hernia  Herniation of abdominal viscera into thorax Failure of pleuroperitoneal canal to close Prevents normal lung development  lung hypoplasia Diaphragma Airway maldevelopment  reduced number of alveoli, tic hernia low lung compliance, reduce ventilation and oxygenation Pulmonary vascular hypoplasia  pulmonary hypertension, right-to-left shunt via PDA and hypoxemia Diaphragmatic hernia High mortality (30-50%) Incidence 1:3000 live births Male:Female (1:2) 90% - posterolateral (Bochdalek) 85% of the lesions are on the left side 2% - anterior (Morgagni) Remainder – anteromedial, paraoesophageal, eventrations Diaphragmatic hernia Associated anomalies CVS 13-23% ie VSD, ASD, TOF, COA CNS 28% ie spina bifida, hydrocephalus GIT 20% ie malrotation and atresia GUT 15% ie hypospadias  Respiratory distress Cyanosis Apparent dextrocardia Scaphoid abdomen with barrel chest Diminished air entry on affected side Presentatio Bowel sound in chest Diagnosis on prenatal ultrasound ns - Lung to head circumference - Diameter of proximal pulmonary artery indexed to the descending aorta - Intrathoracic position of liver  Minor herniation Asymptomatic at birth Incidental finding/late presentation Major herniation Respiratory distress at birth – requiring Diaphragm mechanical ventilation atic hernia Hypoxia, pulmonary hypertension Right to left shunt via PDA Preductal (upper) and postductal (lower) pulse oximetry Difference in PaO2 >20mmHg or SpO2 >10% is significant  Delay surgery and concentrate on medical stabilization (hemodynamic and respiratory support)  improves outcome If cannot be stabilized, proceed with surgery with HFOV/ECMO/Nitric oxide Initial resuscitation Preoperative Intubation if respiratory distress  to improve oxygenation care OG tube to decompress stomach Avoid PPV by facemask Ventilate with high rate and low pressure to avoid barotrauma Correct hypothermia, acidosis and hypoglycemia  Lung protective ventilation strategies Permissive hypercapnia and hypoxemia Post ductal pCO2 40-65mmHg Preductal spO2 85-90% Pressure limited ventilation (10% General Alert, restless, thirsty Lethargic, restless, Drowsy, sweaty, cold thirsty Pulse Normal Increased, weak Rapid, feeble Ant fontanel Normal Sunken Markedly depressed Skin turgor Normal Reduced Markedly reduced Eye Normal Sunken, dry Markedly sunken, very dry Mucous membrane Normal Dry Very dry Capillary refill Normal 2sec Blood pressure Normal Normal/low Low/very low Respiration Normal Deep Deep/rapid Urine output Adequate Decreased Oliguria/anuria Pyloric stenosis Assessment of dehydration Pyloric stenosis Metabolic derangement Vomiting  loss of Na+, K+, Cl-, H+ Renal compensation for metabolic alkalosis  large HCO3 load exceed absorptive treshold  HCO3- excreted with Na+  alkaline urine Persistent vomiting  hypovolemia  RAAS activation  body conserve Na+ and excrete K+, H+ with HCO3-  paradoxical aciduria and worsening hypokalemia  worsen metabolic alkalosis Respiratory compensation for metabolic alkalosis  hypoventilation and apnoea  respiratory acidosis (insufficient as hypoxic drive will be triggered) Severe dehydration  hypovolemic shock with impaired renal and hepatic function  metabolic acidosis and oliguria  respiratory alkalosis  Adverse effects of metabolic alkalosis Shifting of O2 dissociation curve to the left, thus unloading less oxygen at tissue level More important in newborn as they still have fetal hemoglobin with low value of p50 Respiratory compensation with hypoventilation  atelectasis, apnoea Decrease ionized calcium Increase potential for seizure Pyloric stenosis Pyloric stenosis Severit pH pCO2 CO2 pO2 Na K Cl HCO3 y Mild Moderat e Severe  Pre-op Management Pyloric Correct hypovolemia/dehydration Correct metabolic derangement stenosis Prevention of aspiration due to risk of regurgitation Fluid 5-10% dehydration Maintenance fluid % fluid loss x body weight = deficit in ml First 48hours of life NS 75ml/kg/day or 3ml/kg/hr Replace deficit over 24 hours (1/2 over 2days – 1month old first 8hours, then ½ over 16hours) 150ml/kg/day or 6ml/kg/hr Add maintenance fluid 1/5NSD5% 1month old onward (up to 10kg) >10% dehydration 100ml/kg/day or 4ml/kg/hr Impending shock Rapid 10-20ml/kg bolus NS Replacement of losses When circulation and renal function Evaporative, 3rd space loss, restored  replace deficits over 24-48hours from lungs  add potassium to infusion 3-5ml/kg/hr  Electrolyte imbalance Maintenance electrolytes Pyloric Sodium 3-5mmol/kg/day Potassium 2-3mmol/kg/day stenosis Chloride 1-3mmol/kg/day Timing of surgery Not an emergency surgery Surgical procedure Hemodynamic stable Pyloromyotomy (Ramstedt) Pyloric muscle fibres split Well hydrated with good urine output without cutting mucosa Biochem Open vs laparoscopic vs pH 130 Cl- >90 K+ >3 HCO3