Pediatric Surgery (Pg 68-81) I.I. Periop. Management: A.A. Fluids & electrolytes 1.1. Peds have: Incr. metabolism, rapid & major fluid shifts, Decr. concentrating & diluting ability (can’t compensate as well) 2.2. Neonates: Highly incr. proportion of TBW (Incr. ECF) 3.3. Fliud/electrolytes requirements: a)a) Maintenance: D5% in ¼ NS + 20 mEq/L KCl (Table 2-1) b) b) Pre-existing deficits: Rapid restore IV volume – – usually isotonic losses in surgery (Table 2-2) c)c) Abnormal ongoing losses: (1) Measurable 3rdrd space loss (External: GI, drainage tubes) (a) Vol-to-vol replacement (2) Immeasurable: Pathologically sequestered in body (a) Estimated balanced salt soln. replacement (b) Adequacy of replacement based on response (i)(i) UO > 1-2 in infants (ii) UO > 0.5 in teens B.B. Nutrition: 1.1. Enteral: more physiologic, decr. complications, decr. cost a)a) W/o enteral, get mucosal atrophy, enterohepatic circulation stagnation, potential bacterial contamination & sepsis b) b) Baby who can’t suck: use NG tube c)c) Long term need for feedings in ped: G-tube 2.2. Parernteral: a)a) Periph: preferred (easier cath insertion, decr. complications) (1) Up to 12.5% Glc + emulsified fat b) b) Central: via IVC (1) M.C. Complication = mechanical probs (2) Up to 25% Glc c)c) Liver damage: possible complication of TPN – – usually reverses when TPN d/c’d C.C. Respiratory management (Table 2-6): common b/c peds have incr. needs, are obligate nasal breathers, rely on diaphragm >> chest wall muscles 1.1. Endotracheal tube = most secure airway 2.2. Pressure ventilators: preferred (over vol. ventilators) in infants b/c lungs are small & P vent. is easier to prevent over-inflation, etc. a)a) Use lowest O2 settings possible b/c of high risk of retinal damage & lung fibrosis 3.3. High frequency vent: can get adequate gas exchange w/o high pressure 4.4. ECMO (extracorporeal membrane oxygenation): prolonged cardiopulmonary bypass – – overall survival = 80% in newborns D.D. Operative care/monitoring: 1.1. General anesthesia almost always used 2.2. Lab studies not routinely needed 3.3. Pre-op intake: Older kids - no food or milk 8hrs & NPO hrs, Infants – – 6 & 4 hrs, respectively 4.4. Intraoperative: a)a) Monitor O2 sat - if below 95%, needs immediate investigation b) b) If indwelling cath needed (BP instability), umbilical artery is safe easy access (Central venous caths not often used) c)c) Must prevent hypothermia in peds 5.5. Outpatient: starting at 3 mo for term babies & 52 wks if premature E.E. Emotional support & Pain management: 1.1. Face-mask anesthesia induction in little kids 2.2. Post-op: a)a) Long-acting local n. block during surgery helps for hours afterward & epidural cath can be left in place several days b) b) Avoid IM (administration hurts) c)c) Careful w/ narcotics b/c of apnea (patient-controlled dosing in kids over 5 actually works best) d)d) NSAIDs can be also used II.II. Neonatal surgical conditions - Birth defects = MMC of perinatal mortality in US A.A. Congenital diaphragmatic hernia – – prototype of surgical cause of resp distress 1.1. Types: a)a) Bockdalek: defect of posterolateral diaphragm – – most common b) b) Morgagni: retrosternal – – not often emergencies 2.2. Embryology: pleuroperitoneal canal stays open, viscera pass thru, pulmonary hyperplasia 3.3. Pathophys: compression of lung by herniated viscera, pulmonary hyperplasia, pulmonary hypertension (can cause R to L shunting) 4.4. Presentation: dypnea & cyanosis, decr. breath sounds on side of herniation; confirmed by CXR 5.5. Tx: Resuscitate first then sgx: supplemental O2 & ET intubation w/ mech vent & place NG tube a)a) Pos P vent thru face mask is CI b) b) Sgx: Viscera reduced, diaphragm closed, ECMO used in peds who don’t respond well to vent support 6.6. Px: Mortality = 50% B.B. Neonatal thoracic mass lesions: congenital lobar emphysema, cystic adenomatoid malformation, pulmonary sequestration, foregut duplication cysts 1.1. Can be Sx or a-Sx; Seen on CXR 2.2. Tx: Surgical excision if possible 3.3. Good Px except cystic adenomatoid malformation w/ hydrops C.C. Esophageal atresia & Tracheoesophageal fistula - Usually occur in combo: 1.1. EA=interruption in continuity of upper & lower parts of esoph. 2.2. TEF=abnormal communication btw esophagus & trachea 3.3. Most common combo= upper esoph ends blindly & lower portion communicates w/ trachea (type C) 4.4. Pathophys: Often have “VACTER association” abnormalities a)a) Vertebral, Anal, Cardiac, Tracheal, Esophageal, Radial or Renal b) b) Presentation: (1) EA: immediate chocking & regurg w/ feeding, excess drooling, can’t pass NG tube, Air in abd if w/ TEF (not if isolated EA) (2) TEF (isolated): “H” type worst (get aspiration pneumonia),), Dx w/ endoscopy or contrast swallow c)c) Tx (good Px): Elevate head, double-lumen tube in upper pouch to suction, primary repair if possible, staged repair + gastrotomy if needed D.D. Congenital GI obstruction – – anywhere from stomach to anus (Tables 2-8, 2-9) 1.1. Presentation: Varies according to site of obstruction 2.2. Key signs: Polyhydramnios, Bilious vomiting, Abd distension, &Failure to pass meconium 3.3. Dx w/ Plain x-rays: a)a) Complete Prox: Few dilated bowel loops, air fluid levels, no distal airair b) b) Partial prox: do upper GI contrast study c)c) Distal: many distended bowel loops, do contrast enema to verify 4.4. Tx: Always includes NG tube, IV hydration, prophylactic Abc’s a)a) Duodenal: Commonly causes by atresia & malrotation (1) Atresia often assoc. w/ Down’s syndrome or anular pancreas (2) Malrotation w/ Midgut volvulus most common in first month of life = most dangerous form of intestinal obstruction (3) Malrotation w/ Ladd’s bands: peritoneal attachments to lateral wall cross over duodenum (4) Get “Double Bubble” on x-ray (5) Tx: immediate sgx unless midgut atresia is r/o b) b) Small intestine: due to atresia, meconium ileus, intestinal duplication (1) X-rays: foamy appearing dilated meconium-filled bowel loops & no fluid air levels; calcification on abd x-ray = antenatal perf (2) Duplications = endothelial-lined cystic/tubular structures adjacent to alimentary tract on mesenteric side of nl bowel (3) Tx: Atresia & duplications - resection & primary anastamosis Meconium ileus – – often nonoperative tx w/ Gastrographin (diatrizoate) enemas (radiopaque fluid)… if persists or if perf present, need sgx c)c) Colon: Hirschprung’s, meconium plug, neonatal small L colon syndrome, atresia (rare) (1) W/ Hirschprung’s rectosigmoid colon is most common site for boundry btw aganglionic colon & dilated nl colon; can present immediately or later in childhood (2) Dx w/ contrast enema, anorectal manometry, & rectal bx (3) Tx is usually staged: Temporary colostomy, then pull- trhough to anastomose proximal (ganglionic) bowel w/ anal canal (4) Probs: severe entercolitis w/ dehydration, peritonitis, & sepsis (5) Meconium plug (in premature babies) & small L colon syndrome (baby of DM moms) – – contrast enema both Dx & Tx Pediatric Surgery pp.. 81-91 Anorectal Malformations -- aka imperforate anus; rectum does not reach its normal perineal termination -- high malformation –– rectum ends above levator muscles oo rectum may end blindly, but usually terminates in anterior fistulous tract oo Boys –– fistula to urethra or bladder oo Girls –– fistula to vagina -- low malformation –– rectum passes through levator muscles but does not terminate at external sphincter oo fistula drains externally, but anterior to normal anal site oo boys –– small opening in ant. Perineum or forward to scrotal raphe oo girls –– small opening in ant. Perineum or posterior vulva behind hymen cloaca –– rare, occurs in girls; single opening for rectum, vagina, and urethra -- diagnosis oo if low lesion, can usu. see external fistula oo if no external fistula, assume high lesion; may see stool from vagina or urethra in high lesion oo if high or low is unclear, may do “invertogram” by holding baby upside down and performing lateral x-ray. If air is seen within 1 cm of perineal skin, probably low lesion. -- treatment oo continence depends on: external sphincter, internal sphincter, and levator muscles (most important) oo low lesion –– if fisula is only slightly anterior, may not need modification if too anterior to function, surgery –– perineal anoplasty oo intermediate or high lesion –– needs initial colostomy. Then, pull-through procedure in next few months where rectum is pulled through levator swing and anastamosed ttoo perineum. Most common operation: Pena operation. -- prognosis oo low –– excellent prognosis oo high –– difficult to toilet train, may have occasional soiling, may need daily enemas Neonatal Jaundice: Biliary Atresia and Choledochal Cyst normal neonatal jaundice is usu. self-limited; indirect hyperbilirubinemia beware of direct bilirubin >2mg/dL for 2 weeks neonatal cholestatic jaundice: biliary atresia, choledochal cysts, screen for TORCH infections, antitrypsin def., galactosemia, and TPN or hypoxic injury to liver Biliary atresia, neonatal hepatitis, and infantile choledochal cysts may be manifestations of the same disease, but the etiology is unknown percutaneous liver biopsy may also be helpful in dx biliary atresia –– progressive inflammatory obliteration of the bile ducts, beginning around the time of birth presentation: progressive jaundice, pale stools, enlarged liver, elevated conj. Bilirubin, alk phos, and other liver enzymes may do hepatic scintiscan after pretreatment with Phenobarbital to exclude biliary atresia if radionuclide shows up in intestine (shows bile duct patency) treatment: laparotomy to inspect hilum of liver; if intraoperative cholangiogram shows patent bile ducts then dx is probably neonatal hepatitis Kasai portoenterostomy – – drain hepatic ductules at porta hepatis to halt disease process; cut across tissue and anastamose to intestinal tract before child is 8 wks old. 30% do well after this operation. Rest are candidates for liver transplant. Prognosis: depends on diameter of hepatic ductules and absence of hepatic fibrosis. Recurrent postop cholangitis is common, give long-term abx prophylactically.