呼吸衰竭和急性呼吸窘迫综合征-英文课件

1、UTHSCSA Pediatric Resident Curriculum for the PICURESPIRATORY FAILURE & ARDSUTHSCSA Pediatric Resident CurRESPIRATORY FAILUREInability of the pulmonary system to meet the metabolic demands of the body through adequate gas exchange.Two types of respiratory failure:HypoxemicHypercarbicEach can be furt

2、her divided into acute and chronic.Both types of respiratory failure can be present in the same patient.RESPIRATORY FAILUREInability oCENTRAL ETIOLOGIESTrauma: head injury, asphyxiation, hemorrhageInfection: meningitis, encephalitisTumorsDrugs: narcotics, sedativesNeonatal apneaSevere hypoxemia or h

3、ypercarbiaIncreased ICP from any of the above causesCENTRAL ETIOLOGIESTrauma: headOBSTRUCTIVE ETIOLOGIESUpper AirwayAnatomic: choanal atresia, tracheomalacia, tonsillar hypertrophy, laryngeal web, vascular rings, vocal cord paralysis, macroglossiaAspiration: mucus, foreign body, vomitusInfection: ep

4、iglottitis, abscesses, laryngotracheitisTumors: hemangioma, cystic hygroma, papilloma, LaryngpospasmLower AirwayAnatomic: bronchomalacia, lobar emphysemaAspiration: FB, mucus, meconium, vomitusInfection: pneumonia, pertussis, bronchiolitis, CFTumors: teratoma, bronchogenic cystBronchospasmOBSTRUCTIV

5、E ETIOLOGIESUpper AiRESTRICTIVE ETIOLOGIESLung ParenchymaAnatomic: agenesis, cyst, pulmonary sequestrationAtelectasisHyaline membrane diseaseARDSInfection: pneumonia, bronchiectasis, pleural effusion, Pneumocystis cariniiAir leak: pneumothoraxMisc: hemorrhage, edema, pneumonitis, fibrosisChest WallM

6、uscular: diaphragmatic hernia, myasthenia gravis, muscular dystrophy, botulismSkeletal: hemivertebrae, absent ribs, fused ribs, scoliosisMisc: distended abdomen, flail chest, obesityRESTRICTIVE ETIOLOGIESLung ParHYPOXEMIAV/Q mismatchMost common reason. Blood perfuses non-ventilated lung. Seen in ate

7、lectasis, pneumonia, bronchiectasisGlobal hypoventilation: apneaRight-to-left shuntIntracardiac lesions, e.g., tetralogy of FallotIncomplete diffusionOxygen must diffuse across increased distance secondary to interstitial edema, fibrosis, or hyaline membrane.Low inspired FiO2: high altitudeHYPOXEMIA

8、V/Q mismatchHYPERCARBIAPump FailureReduced central drive: apnea, metabolic alkalosis, drugs, brainstem injury, hypoxiaMuscle fatigue: muscular dystrophyIncreased pulmonary workload: decreased compliance, increased obstructionIncreased CO2 production: fever, seizure, malignant hyperthermiaIncreased d

9、ead space: V/Q mismatch (ventilation of non-perfused lung)HYPERCARBIAPump FailurePHYSICAL EXAMTachypneaDyspneaRetractionsNasal flaringGruntingDiaphoresisTachycardiaHypertensionAltered mental statusConfusionAgitationRestlessnessSomnolenceCyanosis (need 5mg/dl of unoxygenated blood)PHYSICAL EXAMTachyp

10、neaAltered CXR FINDINGSCXR may be normal if problem is with upper airwayCan see hyperinflation, atelectasis, infiltrate, cardiomegalyAdditional studies may be needed, e.g., chest CT, barium swallow, echocardiogramCXR FINDINGSCXR may be normal BLOOD GASFor any age patient, breathing room air, respira

11、tory failure is defined as arterial pCO2 50mm Hg or arterial pO2 60mm Hg.If the patient is hyperventilating, a normal pCO2 is disturbing.The above definition assumes the absence of an anatomic shunt.Chronic hypercarbic respiratory failure will often have a normal pH because of compensatory metabolic

12、 alkalosis.BLOOD GASFor any age patient, MANAGEMENTREMEMBER PALSAirwayBreathingCirculationMANAGEMENTREMEMBER PALSAIRWAYRepositioningPosition of comfortJaw thrust/chin liftOral airwayUnconscious patients onlyNasal trumpetNasal or mask CPAPBag-mask ventilationUse during preparation for intubationTrach

13、eal intubationAIRWAYRepositioningBREATHINGDecrease respiratory workload-agonistsDecadron or steroidsAntibioticsCPAPSupplemental O2Nasal cannulaClosed face maskNon-rebreatherCounteract drug effectsBag-mask ventilationMechanical ventilationBREATHINGDecrease respiratory CIRCULATIONSuppress anaerobic me

14、tabolism and acidosisCorrect anemia to improve oxygen deliveryEnsure adequate cardiac outputInotropes: oxygen, vasopressorsFluid bolusesCIRCULATIONSuppress anaerobic 呼吸衰竭和急性呼吸窘迫综合征-英文课件呼吸衰竭和急性呼吸窘迫综合征-英文课件呼吸衰竭和急性呼吸窘迫综合征-英文课件呼吸衰竭和急性呼吸窘迫综合征-英文课件呼吸衰竭和急性呼吸窘迫综合征-英文课件ARDSA patient must meet all of the foll

15、owing: Acute onset of respiratory symptomsCXR with bilateral infiltratesNo evidence of left heart failurePaO2/FiO2 200mm Hg (regardless of PEEP)American-European Consensus Conference on ARDS (Am J Resp Crit Care Med 149:818, 1994)The following are implied:Previously normal lungsDecreased lung compli

16、anceIncreased shuntingHypoxemic respiratory failureARDSA patient must meet all of呼吸衰竭和急性呼吸窘迫综合征-英文课件ETIOLOGYARDS represents about 3% of PICU admissions.Numerous precipitating events:TraumaPneumoniaBurnsSepsisDrowningShockETIOLOGYARDS represents about PATHOPHYSIOLOGYAcute InjuryLatent PeriodEarly Exu

17、dative PhaseCellular Proliferative PhaseFibrotic Proliferative PhasePATHOPHYSIOLOGYAcute InjuryRoyall and LevinJ Peds 112:169-180;335-347, 1988Royall and LevinPATHOLOGY OF ARDSGreen arrows point to hyaline membraneBlue arrows point to type II pneumocytes and alveolar macrophagesPATHOLOGY OF ARDSGree

18、n arrows MANAGEMENTMeticulous supportive care is the mainstay of therapyPrevent secondary lung injuryEnsure adequate cardiac outputLimit secondary infectionsDrugsGood nutritionMANAGEMENTMeticulous supportivVENTILATOR STRATEGIESThe hallmark of ARDS is heterogeneous lung.Limit BarotraumaKeep PIP 35 cm

19、 H2OUse pressure-control ventilationUse TV of 6-10cc/kgKeep rate 7.20Limit O2 ToxicityGive enough PEEP to lower FiO2 to 90%.PEEP E) ventilation.VENTILATOR STRATEGIESThe hallCARDIAC OUTPUTKeep cardiac output 4.5 L/min/m2.Keep O2 delivery 600 ml O2/min/m2.Keep Hct 30%, higher if signs of heart failure

20、.Use inotropes to augment cardiac output.Ensure adequate preload.CARDIAC OUTPUTKeep cardiac outLIMIT SECONDARY INFECTIONSWash your hands.Use the gut as soon as possible for nutrition and meds.Discontinue indwelling catheters as soon as possible.Have high index of suspicion.Treat infections early, but tailor antibiotics to culture results.LIMIT SECONDARY INFECTIONSWashDRUGSDiuretics: a dry lung is a good lung.InotropesSteroids: 2mg/kg/day begun after a week into the course may be of benefit, otherwise dont use.Pulmonary vasodilators (nitric oxide, prostaglan