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Neonatal - Ch. 31
Ch. 31 (Egan's) - Neonatal and Pediatric Respiratory Disorders
Question | Answer |
---|---|
how many infants does neonatal respiratory distress syndrome affect each year in the US? | 60,000-70,000 |
what is another name for RDS and what is RDS? | hyaline membrane disease; a disease of prematurity |
what are the 4 major factors in the pathophysiology of RDS? | qualitative surfactant deficiency, dec. alveolar surface area, incr. small airways compliance, presence of DA |
what does the severe hypoxemia and acidosis increase in RDS? | PVR |
because of the low surfactant production, what happens to the alveolar? from this, what happens? | instability and collapse, leads to increased WOB; incr. surface tension, fluid in alveoli |
the increased PVR leads to what? which overall leads too? | increases right-to-left shunting through the PDA; worsened acidosis, hypoxemia, surfactant production |
what is the first sign in RDS? what occurs next? | tachypnea (occurs soon after birth); retractions, paradoxical breathing, grunting, nasal flaring |
what does chest auscultation reveal? | fine inspiratory crackles |
if central cyanosis is present, what is likely that the infant has? | severe hypoxemia |
what mimics the aspect of RDS? | systemic hypotension, hypothermia, poor perfusion |
what is definitive diagnosis of RDS made with? and what is typically found? | chest radiography; diffuse, hazy, reticulogranular densities w/ air bronchograms w/ low lung vols |
what are the traditional support modes used to manage RDS? what else has been added? | CPAP and PEEP; surfactant replacement therapy and high-freq ventilation |
if the condition is not severe, what is indicated? | a trial of nasal CPAP, 4-6 cmH2O (nasal prongs preferred) |
when should MV with PEEP be initiated? | if oxygenation doesn't improve w/ CPAP or if the pt is apneic or acidotic |
what is the goal of MV for RDS? | prevent lung collapse and maintain alveolar inflation |
what type of tubes are used for ETT? and what type of ventilation is used for infants? | uncuffed; pressure |
what does optimal PEEP provide for RDS? what is done if high PaCO2 persists? what should the PIP be to minimize potential for volutrauma? | lowest PaCO2, highest PaO2; must increase f or PIP; less than 30 cmH2O, lower for more immature infants |
what are the 3 surfactant preparations to manage RDS? | 1. beractant (survanta) 2. calfactant (infasurf) 3. poractant alfa (curosurf) |
how is the surfactant given to infant? | liquid suspensions that are instilled directly into trachea; all given through ETT |
what is the dosing, ml/kg, administration, and dosing interval for beractant (survanta)? | 100; 4; 1/4 dose quickly in each of 4 positions; Q6 or more often |
what is the dosing, ml/kg, administration, and dosing interval for calfactant (infasurf)? | 100; 3; 1/2 dose slowly supine then rotated; Q12 or more often |
what is the dosing, ml/kg, administration, and dosing interval for poractant alfa (curosurf)? | 100-200; 1.25-2.5; whole or 1/2 dose supine; Q12 or more often |
what is the most common respiratory disorder of the newborn? | transient tachypnea of the newborn (type II RDS) |
what is the likely cause of TTN? | delayed clearance of fetal lung liquid |
how much does the birth canal squeeze normally accounts for clearance? what accounts for the final third? | 2/3; lyphatics' absorption (immature lymphatics impairs absorption) |
what are the first clinical manifestations of TTN? | tachypnea; normal VA, pH, and PaCO2 |
what does the chest radiograph reveal? | looks like pneumonia; hyperinflation, pleural effusions, perihilar streaking (lymphatic engorgement) |
what is the most common treatment that infants respond to in TTN? | low FiO2 by infant oxygen hood or nasal cannula; need higher FiO2, use CPAP |
what is given once a culture is obtained? | antibiotics |
how long should it take to show clearing of the lungs on chest radiograph and clinical improvement? | 24-48 hours |
what is meconium aspiration syndrome a disease of? what does it involve and associated with? | term and near-term infants; aspiration of meconium in central airways of the lung; perinatal depression and asphyxia |
what does meconium consist of? | mucopolysaccharides, cholesterol, bile acids and salts, intestinal enzymes, others |
amniotic fluid stained with meconium is found in approximately ___ of all births. it is rare if the infant is less than ___ weeks' gestation age. ___ of infants w/ inhaled meconium clear lungs spontaneously. | 12%; 37; 95 |
what is the real causative agent in MAS? | fetal asphyxia that precedes after aspiration |
what are the 3 primary problems of MAS? | 1. pulmonary obstruction 2. lung tissue damage 3. pulmonary HTN |
the lung tissue injury caused by MAS is _________ __________. | chemical pneumonia |
what is evidence that the fetus is at high risk of MAS? | thick meconium, fetal tachycardia, absent fetal cardiac accelerations during labor |
what do infants normally have with MAS? | gasping respirations, tachypnea, grunting, retractions |
what does the chest radiograph show? | irregular pulmonary densities (areas of atelectasis), hyperlucent areas (hyperinflation from air-trapping) |
what does the ABG normally show? and what happens in severe cases? | hypoxemia with mixed resp and metabolic acidosis; R-to-L shunting and persistent PHTN |
what should be done first for treatment? | immediate intubation and suctioning; after ETT is inserted, it is removed to see meconium, if there is new ETT is inserted |
what is indicated if the primary problem is hypoxemia? what if resp acidosis is severe and excessive WOB? | CPAP; MV |
what is shown to decrease the risk of air leak in MAS? | HFV and SIMV |
what has become a major adjunt in the management of persistent pulmonary hypertension? | nitric oxide (DO NOT use high mean airway pressures) |
what infants may have bronchopulmonary dysplasia? | infants with severe respiratory failure in the first few weeks of life |
what have been implicated in the origin of BPD? | immaturity, genetics, malnutrition, O2 toxicity, MV |
what are the intiating factors of BPD? | atelectrauma and volutrauma |
what conditions lead to BPD? | hyperoxia/hypoxia, mechanical forces, vascular maldevelopment, inflammation, nutrition, genetics |
__________ is the term coined to describe loss of alveolar volume that is both a consequence and a cause of lung injury. ____________ is the term used to describe local overinflation (and thus stretch) of airways and alveoli. | atelectrauma; volutrauma (both increase lung injury) |
what does atelectrauma and volutrauma cause a need for? | increased supplemental O2 concentrations |
what is the "new" BPD? | decreased alveolarization rather than prominent airway damage of the "old" BPD |
what occurs approximately 2-3 weeks of life? | progressive respiratory distress (needs O2 and MV) |
what does the chest radiograph for severe disease show? | atelectasis, emphysema, fibrosis diffusely intermixed |
what does the ABG look like? | hypoxemia and hypercapnia secondary to airway obstruction, air-trapping, pulm fibrosis, atelectasis |
what is the best management of BPD? | prevention |
_________ should be delivered early in the course of treatment. | surfactant |
what is involved in the treatment steps of BPD? | minimize additional lung damage and prevent pulmonary HTN and cor pulmonale |
________ are given as needed to decrease pulmonary edema; __________ are given to manage existing pulmonary infection. ______ ___________ for retained secretions. ____________ therapy to decrease RAW. | diuretics; antibiotics; chest physiotherapy; bronchodilator |
what is given to produce substantial short-term improvement in lung function, often allowing rapid weaning from ventilatory support? | steroid therapy with dexamethasone |
what are the periods of apnea of prematurity in infants? | 5-10 seconds followed by 10-15 seconds of rapid respiration |
when are the apneic spells abnormal? | 1. they last longer than 15 secs 2. they are associated with cyanosis, pallor, hypotonia, or bradycardia |
when is it considered central apnea? | if no effort to breathe occurs during a spell |
when is it considered obstructive apnea? | if breathing efforts occur but obstruction prevents air flow |
when is it considered mixed apnea? | combination, that starts as obstructive and develops into central |
premature infants have an immature ____________ of ___________ ______. | chemo-control; respiratory drive |
what should be managed in infants with apnea? and what can terminate apnea periods in infants? | underlying cause if identified; tactile stimulation |
______ is used to reduce mixed and obstructive apnea by splinting the upper airway. | CPAP |
what does apnea secondary to prematurity respond well to? if they dont respond well to this, what is used? | theophylline and caffiene; doxapram |
_________ decreases hypoxic depression by increasing oxygen-carrying capacity. _________ __________ provides support when respiratory effort is inadequate. | transfusion; mechanical ventilation |
when does periods of apnea begin to disappear? | 37-44 of postmenstrual age with no apparent long-term effects |
what is a common denominator in persistent pulmonary hypertension of the newborn? | return to fetal circulatory pathways, usually because of high PVR |
what does this condition result in? | further R-L shunting, severe hypoxemia, and metabolic and resp acidosis |
what 2 anatomic shunts does the fetus have? | foramen ovale and the ductus arteriosus |
the intrauterine total pulmonary blood flow is ____. | low |
when is it definite that the infant has PPHN? | if the PVR does not decrease to allow the PVR/SVR ratio to become less than 1 |
what are the 3 fundamental types of PPHN? | 1. vascular spasm 2. increased muscle wall thickness 3. decreased cross-sectional area of pulmonary vessels |
what is vascular spasm? | acute event thats triggered by hypoxemia, hypoglycemia, hypotension, and pain |
what is increased wall thickness? | chronic condition develops in utero in response to several different factors (chronic fetal hypoxia, incr pulm blood flow, pulm venous obstruction) |
what is decreased cross-sectional area of vasculature related to? | hypoplasia of the lungs and occurs with congenital diaphragmatic hernia, absent kidneys, and decreased amniotic fluid |
when should PPHN be suspected? | when rapidly changing SpO2 hypoxemia is worse than indicated on chest radiograph |
how is this detected? | performing preductal and postductal SpO2 (pred should be >5% post) |
what is the initial therapy for PPHN? | removal of underlying cause, hypoxemia w/ O2 and surfactant for RDS |
what if correction does not correct hypoxemia? | needs intubation and MV; sedation, paralysis; HFV; inhaled nitric oxide; ECMO (if all fails) |
what are the three fundamental mechanisms of airway abnormalities? | internal obstruction, external obstruction, disruption |
what does internal obstruction include? | laryngomalacia, tracheomalacia, laryngeal webs, tracheal stenosis, hemangiomas |
what do these conditions manifest as? | inspiratory stridor, gas trapping, expiratory wheezing, accessory resp muscle activity |
what is caused by external obstruction? | hemangiomas, neck or thoracic masses, vascular rings |
airway disruptions usually are related to ____________ ________ in a newborn. | tracheoesophageal fistula (usually associated with esophageal atresia) |
what are the 5 types of TEF? | esophageal atresia w/ proximal fistula; distal fistula; w/ both; w/out either; w/ intact esophagus w/ H fistula |
what is the most common of these? least common? | esophageal atresia w/ a distal fistula (85%-90%); H fistula |
what do all these malformations manifest as? | difficulty swallowing, bubbling/frothing at mouth, choking |
what is TEF managed with? | surgical ligation of the fistula and reconnection of the interrupted esophagus |
what is the most common severe lung malformation? | congenital cystic adenomatoid malformation of the lung (C-CAM) |
what is the usual treatment of C-CAM? | surgical removal of the affected lobe |
what are less common lung malformations? | pulmonary sequestration and lobar emphysema |
what is congenital diaphragmatic hernia? | severe disease that usually manifests in newborns as severe respiratory distress |
what is the pathophysiologic mechanism of CDH? | lung hypoplasia and abnormal development |
what are the 2 types of hernia? | 1. Bochdalek hernia (lateral/posterior, left) 2. Morgagni hernia (medial/anterior, either side) |
what might physical examination include in CDH? | scaphoid abdomen, decreased breath sounds, displaced heart sounds, severe cyanosis |
what is the initial treatment? | intubation, paralysis, MV, continuous gastric suction |
what is delayed in tx? | surgical repair for PVR to fall |
what can large defects in the abdominal wall cause? | severe respiratory compromise, most commonly omphalocele |
what is omphalocele? | abdominal wall defect involving insertion of umbilical cord |
what must omphalocele be distinguised from? | gastroschesis (abdominal wall defect that is completely separate from the insertion of UC) |
what diseases are included in poor neuromuscular control? | spinal muscular atrophy, congenital myasthenia gravis, myotonic dystrophy, and others |
what are the 2 large categories of congenital heart diseases? | cyanotic and acyanotic |
what are cyanotic heart diseases? | blood shunts from R to L, bypassing the lungs, thus deoxygenated |
what are acyanotic heart diseases? | blood shunts from L to R, thus causes CHF |
what are the 2 most common cyanotic heart diseases? | 1. tetralogy of Fallot 2. transposition of the great arteries |
what does tetralogy of Fallot include? | 1. pulmonary stenosis 2. ventricular septal defect 3. dextroposition of aorta 4. RV hypertrophy |
what does a mild case manifest as? | heart murmur, intermittent severe cyanotic spells, infant squatting/entering knee chest position |
what does a severe case manifest as? | heart murmur and severe continuous cyanosis |
what is transposition of the great arteries? | the heart disease that most frequently causes severe cyanosis |
what does it manifest as? | mod-severe cyanosis immediately after birth |
what treatment is frequently needed? | emergency atrial septostomy (cutting a hole in the wall b/t two atria) |
what is the goal? | allow PVR to decrease and then perform arterial switch operation in the 2nd or 3rd wk of life |
what is the most common congenital heart disease? | ventricular septal defect |
what is among the most severe of congenital heart diseases? | hypoplastic left heart syndrome |
what does VSD result in and when does it appear? | left-to-right shunt and CHF; 6-8 wks as PVR falls |
what is the most common type of atrial septal defect? | small, slit-like opening that persists after closure of the foramen ovale |
what is patent ductus arteriosus treated with? | indomethacin (pharmacologic) or ligation (surgical) |
what are the 3 accepted treatments of hypoplastic left heart syndrome? | comfort care (allows infant to die), palliative surgical procedure, transplantation |
what is the leading cause of death among infants younger than 1 year in the US? | SIDS |
what infant normally dies to SIDS? | preterm african-american boy born to a poor mother <20 w/ inadequate prenatal care |
what age is most suseptible and when does it normally occur? | 1-3 months; night during winter months |
the _______ sleeping position has been strongly associated with increased risk of SIDS. | prone |
_________ is the treatment of SIDS and what does this include? | prevention; identification of risk, trained in apnea monitoring/CPR, supine/side-lying position, reduce soft objects during sleep |
what is gastroesophageal reflux disease? | regurgitation of stomach contents into the esophagus |
what are the respiratory problems associated with GERD? | reactive airway disease, aspiration pneumonia, laryngospasm, stridor, chronic cough, choke, apnea |
___________ is an acute infection of the lower respiratory tract, usually caused by the RSV. | bronchiolitis |
what is the clinical manifestations of bronchiolitis? | inflammation/obstruction of small bronchi/bronchioles |
when does it occur? | after a viral upper respiratory infection (fever, cough, dyspnea, tachypnea, wheezes) |
what does the chest radiograph show? | hyperinflation with areas of consolidation |
what is the treatment of bronchiolitis? | relief of airway obstruction and hypoxemia; systemic hydration, croup tent, O2 hood, NC |
_________ is given to decrease the length of MV in severe cases. | ribavirin |
______ is a viral disorder of the upper airway that normally results in subglottic swelling and obstruction. | croup (laryngotracheobronchitis) |
what is viral infection resulting in subglottic swelling? | the most common cause of obstruction in 6 month-6 year olds |
when do the symptoms become evident? | after 2-3 days of nasal congestion, fever, coughing; stridor, barking cough, dyspnea, cyanosis, exhaustion |
what does the chest radiograph show? | subglottic narrowing of trachea, "steeple sign" |
what is the treatment of croup? | cool mist; supplemental O2; aerosolized racemic epinephrine and dexamethasone; budesonide; MV |
__________ is an acute and often life-threatening infection of the upper airway that causes severe obstruction secondary to supraglottic swelling. what is the most common cause? | epiglottitis; H. influenzae type B infection |
what are the clinical manifestations of epiglottitis? | high fever, sore throat, stridor, labored breathing, muffled voice |
what does the LATERAL NECK radiograph show? | epiglottis thickened and flattened ("thumb sign"), aryepiglottic folds swollen, vallecula may not be visualized |
what is the treatment of epiglottitis? | elective intubation under general anesthesia, place on CPAP w/ low PSV (3 cmH2O) |
what is the most common lethal genetic disease among caucasian americans? what does it involve? | CF; gene mutation affecting chloride movement, particularly in exocrine glands |
what are the most severely affected organs? | sweat glands, pancreas, lungs; skin is salty |
what does pancreatic insufficiency lead to? | malnutrition, diarrhea, steatorrhea |
what is the leading cause of death among patients with CF? | complications of lung disease |
what do the patients produce? | copious amounts of thick sputum; retained secretions lead to recurrent infections, atelectasis, pneumonia or lung abscesses |
what is the treatment of CF? | pancreatic enzyme supplements; CPT, exercise; DNase, 7% saline; antibiotics (tobramycin); ibuprofen, bronchodilators |
what is the most commonly used form of lung transplantation in the treatment of CF? | double-lung transplantation |
what is the median survival age of patients with CF? | 38 years |