UTHSCSA Pediatric Resident Curriculum for the PICU UTHSCSA Pediatric Resident Curriculum for the PICU RESPIRATORY FAILURE RESPIRATORY FAILURE & ARDS & ARDS
Jan 19, 2016
UTHSCSA Pediatric Resident Curriculum for the PICUUTHSCSA Pediatric Resident Curriculum for the PICU
RESPIRATORY FAILURE RESPIRATORY FAILURE
& ARDS& ARDS
RESPIRATORY FAILURERESPIRATORY FAILURE Inability of the pulmonary system to meet the metabolic Inability of the pulmonary system to meet the metabolic
demands of the body through adequate gas exchange.demands of the body through adequate gas exchange. Two types of respiratory failure:Two types of respiratory failure:
HypoxemicHypoxemic HypercarbicHypercarbic
Each can be further divided into acute and chronic.Each can be further divided into acute and chronic. Both types of respiratory failure can be present in the same Both types of respiratory failure can be present in the same
patient.patient.
CENTRAL ETIOLOGIESCENTRAL ETIOLOGIES Trauma: head injury, asphyxiation, hemorrhageTrauma: head injury, asphyxiation, hemorrhage Infection: meningitis, encephalitisInfection: meningitis, encephalitis TumorsTumors Drugs: narcotics, sedativesDrugs: narcotics, sedatives Neonatal apneaNeonatal apnea Severe hypoxemia or hypercarbiaSevere hypoxemia or hypercarbia Increased ICP from any of the above causesIncreased ICP from any of the above causes
OBSTRUCTIVE ETIOLOGIESOBSTRUCTIVE ETIOLOGIESUpper AirwayUpper Airway Anatomic: choanal atresia, Anatomic: choanal atresia,
tracheomalacia, tonsillar tracheomalacia, tonsillar hypertrophy, laryngeal web, hypertrophy, laryngeal web, vascular rings, vocal cord vascular rings, vocal cord paralysis, macroglossiaparalysis, macroglossia
Aspiration: mucus, foreign body, Aspiration: mucus, foreign body, vomitusvomitus
Infection: epiglottitis, abscesses, Infection: epiglottitis, abscesses, laryngotracheitislaryngotracheitis
Tumors: hemangioma, cystic Tumors: hemangioma, cystic hygroma, papilloma, hygroma, papilloma,
LaryngpospasmLaryngpospasm
Lower AirwayLower Airway Anatomic: bronchomalacia, Anatomic: bronchomalacia,
lobar emphysemalobar emphysema Aspiration: FB, mucus, Aspiration: FB, mucus,
meconium, vomitusmeconium, vomitus Infection: pneumonia, Infection: pneumonia,
pertussis, bronchiolitis, CFpertussis, bronchiolitis, CF Tumors: teratoma, Tumors: teratoma,
bronchogenic cystbronchogenic cyst BronchospasmBronchospasm
RESTRICTIVE ETIOLOGIESRESTRICTIVE ETIOLOGIESLung ParenchymaLung Parenchyma Anatomic: agenesis, cyst, Anatomic: agenesis, cyst,
pulmonary sequestrationpulmonary sequestration AtelectasisAtelectasis Hyaline membrane diseaseHyaline membrane disease ARDSARDS Infection: pneumonia, Infection: pneumonia,
bronchiectasis, pleural bronchiectasis, pleural effusion, effusion, Pneumocystis cariniiPneumocystis carinii
Air leak: pneumothoraxAir leak: pneumothorax Misc: hemorrhage, edema, Misc: hemorrhage, edema,
pneumonitis, fibrosispneumonitis, fibrosis
Chest WallChest Wall Muscular: diaphragmatic Muscular: diaphragmatic
hernia, myasthenia gravis, hernia, myasthenia gravis, muscular dystrophy, muscular dystrophy, botulismbotulism
Skeletal: hemivertebrae, Skeletal: hemivertebrae, absent ribs, fused ribs, absent ribs, fused ribs, scoliosisscoliosis
Misc: distended abdomen, Misc: distended abdomen, flail chest, obesityflail chest, obesity
HYPOXEMIAHYPOXEMIAV/Q mismatchV/Q mismatch
Most common reason. Blood perfuses non-ventilated lung. Seen Most common reason. Blood perfuses non-ventilated lung. Seen in atelectasis, pneumonia, bronchiectasisin atelectasis, pneumonia, bronchiectasis
Global hypoventilationGlobal hypoventilation:: apnea apnea
Right-to-left shuntRight-to-left shunt Intracardiac lesions, e.g., tetralogy of FallotIntracardiac lesions, e.g., tetralogy of Fallot
Incomplete diffusionIncomplete diffusion Oxygen must diffuse across increased distance secondary to Oxygen must diffuse across increased distance secondary to
interstitial edema, fibrosis, or hyaline membrane.interstitial edema, fibrosis, or hyaline membrane.
Low inspired FiOLow inspired FiO22: : high altitudehigh altitude
HYPERCARBIAHYPERCARBIAPump FailurePump Failure
Reduced central drive: apnea, metabolic alkalosis, drugs, Reduced central drive: apnea, metabolic alkalosis, drugs, brainstem injury, hypoxiabrainstem injury, hypoxia
Muscle fatigue: muscular dystrophyMuscle fatigue: muscular dystrophy Increased pulmonary workload: decreased compliance, Increased pulmonary workload: decreased compliance,
increased obstructionincreased obstruction
Increased COIncreased CO22 production production: : fever, seizure, malignant fever, seizure, malignant
hyperthermiahyperthermia
Increased dead spaceIncreased dead space: : V/Q mismatch (ventilation of V/Q mismatch (ventilation of non-perfused lung)non-perfused lung)
PHYSICAL EXAMPHYSICAL EXAM TachypneaTachypnea DyspneaDyspnea RetractionsRetractions Nasal flaringNasal flaring GruntingGrunting DiaphoresisDiaphoresis TachycardiaTachycardia HypertensionHypertension
Altered mental statusAltered mental status ConfusionConfusion AgitationAgitation RestlessnessRestlessness SomnolenceSomnolence
Cyanosis (need 5mg/dl Cyanosis (need 5mg/dl of unoxygenated blood)of unoxygenated blood)
CXR FINDINGSCXR FINDINGS CXR may be normal if problem is with upper airwayCXR may be normal if problem is with upper airway Can see hyperinflation, atelectasis, infiltrate, Can see hyperinflation, atelectasis, infiltrate,
cardiomegalycardiomegaly Additional studies may be needed, e.g., chest CT, Additional studies may be needed, e.g., chest CT,
barium swallow, echocardiogrambarium swallow, echocardiogram
BLOOD GASBLOOD GAS For any age patient, breathing room air, respiratory For any age patient, breathing room air, respiratory
failure is defined as arterial pCOfailure is defined as arterial pCO22 > 50mm Hg or arterial > 50mm Hg or arterial
pOpO22 < 60mm Hg. < 60mm Hg.
If the patient is hyperventilating, a normal pCOIf the patient is hyperventilating, a normal pCO22 is is
disturbing.disturbing. The above definition assumes the absence of an The above definition assumes the absence of an
anatomic shunt.anatomic shunt. Chronic hypercarbic respiratory failure will often have a Chronic hypercarbic respiratory failure will often have a
normal pH because of compensatory metabolic alkalosis.normal pH because of compensatory metabolic alkalosis.
MANAGEMENTMANAGEMENT
REMEMBER PALSREMEMBER PALSAAirwayirway
BBreathingreathing
CCirculationirculation
AIRWAYAIRWAY RepositioningRepositioning
Position of comfortPosition of comfort Jaw thrust/chin liftJaw thrust/chin lift
Oral airwayOral airway Unconscious patients onlyUnconscious patients only
Nasal trumpetNasal trumpet Nasal or mask CPAPNasal or mask CPAP Bag-mask ventilationBag-mask ventilation
Use during preparation for intubationUse during preparation for intubation
Tracheal intubationTracheal intubation
BREATHINGBREATHING Decrease respiratory workloadDecrease respiratory workload
ß-agonistsß-agonists Decadron or steroidsDecadron or steroids AntibioticsAntibiotics CPAPCPAP
Supplemental OSupplemental O22
Nasal cannulaNasal cannula Closed face maskClosed face mask Non-rebreatherNon-rebreather
Counteract drug effectsCounteract drug effects Bag-mask ventilationBag-mask ventilation Mechanical ventilationMechanical ventilation
CIRCULATIONCIRCULATION
Suppress anaerobic metabolism and acidosisSuppress anaerobic metabolism and acidosisCorrect anemia to improve oxygen deliveryCorrect anemia to improve oxygen deliveryEnsure adequate cardiac outputEnsure adequate cardiac output
Inotropes: oxygen, vasopressorsInotropes: oxygen, vasopressors Fluid bolusesFluid boluses
ARDSARDS A patient must meet all of the following: A patient must meet all of the following:
Acute onset of respiratory symptomsAcute onset of respiratory symptoms CXR with bilateral infiltratesCXR with bilateral infiltrates No evidence of left heart failureNo evidence of left heart failure PaOPaO22/FiO/FiO22 < 200mm Hg (regardless of PEEP) < 200mm Hg (regardless of PEEP)
American-European Consensus Conference on ARDS (Am J Resp Crit Care Med American-European Consensus Conference on ARDS (Am J Resp Crit Care Med 149:818, 1994)149:818, 1994)
The following are implied:The following are implied: Previously normal lungsPreviously normal lungs Decreased lung complianceDecreased lung compliance Increased shuntingIncreased shunting Hypoxemic respiratory failureHypoxemic respiratory failure
ETIOLOGYETIOLOGY ARDS represents about 3% of PICU admissions.ARDS represents about 3% of PICU admissions. Numerous precipitating events:Numerous precipitating events:
TraumaTrauma PneumoniaPneumonia BurnsBurns SepsisSepsis DrowningDrowning ShockShock
PATHOPHYSIOLOGYPATHOPHYSIOLOGY Acute InjuryAcute Injury Latent PeriodLatent Period Early Exudative PhaseEarly Exudative Phase Cellular Proliferative PhaseCellular Proliferative Phase Fibrotic Proliferative PhaseFibrotic Proliferative Phase
Royall and LevinJ Peds 112:169-180;335-347, 1988
PATHOLOGY OF ARDSPATHOLOGY OF ARDS
Green arrows point to hyaline membraneGreen arrows point to hyaline membrane
Blue arrows point to type II pneumocytes and alveolar macrophagesBlue arrows point to type II pneumocytes and alveolar macrophages
MANAGEMENTMANAGEMENT Meticulous supportive care is the mainstay of therapyMeticulous supportive care is the mainstay of therapy
Prevent secondary lung injuryPrevent secondary lung injury Ensure adequate cardiac outputEnsure adequate cardiac output Limit secondary infectionsLimit secondary infections DrugsDrugs Good nutritionGood nutrition
VENTILATOR STRATEGIESVENTILATOR STRATEGIESThe hallmark of ARDS is heterogeneous lung.The hallmark of ARDS is heterogeneous lung.
Limit BarotraumaLimit Barotrauma Keep PIP <35 cm HKeep PIP <35 cm H22OO
Use pressure-control Use pressure-control ventilationventilation
Use TV of 6-10cc/kgUse TV of 6-10cc/kg Keep rate <30 bpmKeep rate <30 bpm Permissive hypercapniaPermissive hypercapnia Use bicarb or THAM to Use bicarb or THAM to
keep pH >7.20keep pH >7.20
Limit OLimit O22 Toxicity Toxicity Give enough PEEP to Give enough PEEP to
lower FiOlower FiO22 to <60% while to <60% while
maintaining Omaintaining O22 >90%. >90%.
PEEP <15 cm HPEEP <15 cm H22O O
shouldn’t decrease shouldn’t decrease cardiac output.cardiac output.
Increase mean airway Increase mean airway pressure with inverse pressure with inverse ratio (I>E) ventilation.ratio (I>E) ventilation.
CARDIAC OUTPUTCARDIAC OUTPUT Keep cardiac output >4.5 L/min/mKeep cardiac output >4.5 L/min/m22.. Keep OKeep O22 delivery >600 ml O delivery >600 ml O22/min/m/min/m22..
Keep Hct >30%, higher if signs of heart failure.Keep Hct >30%, higher if signs of heart failure. Use inotropes to augment cardiac output.Use inotropes to augment cardiac output. Ensure adequate preload.Ensure adequate preload.
LIMIT SECONDARY INFECTIONSLIMIT SECONDARY INFECTIONS
Wash your hands.Wash your hands. Use the gut as soon as possible for nutrition and Use the gut as soon as possible for nutrition and
meds.meds. Discontinue indwelling catheters as soon as Discontinue indwelling catheters as soon as
possible.possible. Have high index of suspicion.Have high index of suspicion. Treat infections early, but tailor antibiotics to culture Treat infections early, but tailor antibiotics to culture
results.results.
DRUGSDRUGS Diuretics: a dry lung is a good lung.Diuretics: a dry lung is a good lung. InotropesInotropes Steroids: 2mg/kg/day begun after a week into the Steroids: 2mg/kg/day begun after a week into the
course may be of benefit, otherwise don’t use.course may be of benefit, otherwise don’t use. Pulmonary vasodilators (nitric oxide, prostaglandins, Pulmonary vasodilators (nitric oxide, prostaglandins,
nitroprusside): of little benefit. NO may be of benefit nitroprusside): of little benefit. NO may be of benefit in some patients.in some patients.
Surfactant replacement: probably no benefitSurfactant replacement: probably no benefit NSAIDs: no clinical benefitNSAIDs: no clinical benefit
NUTRITIONNUTRITION Ensure adequate calories as soon as possible:Ensure adequate calories as soon as possible:
50-60kcal/kg/day in infants50-60kcal/kg/day in infants 35-45kcal/kg/day in older children.35-45kcal/kg/day in older children.
After day 4, increase calories by 25-50% above After day 4, increase calories by 25-50% above baseline.baseline.
Begin enteral feeds as soon as is safe.Begin enteral feeds as soon as is safe. ““Pulmonary” formulas probably of little benefit.Pulmonary” formulas probably of little benefit.
MORTALITY/MORBIDITYMORTALITY/MORBIDITY Published mortality is 50% in children.Published mortality is 50% in children. Pulmonary failure accounts for only 15% of the Pulmonary failure accounts for only 15% of the
deaths. deaths. Lung function usually returns to normal within 18 Lung function usually returns to normal within 18
months after leaving the hospital.months after leaving the hospital.