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 /  \\\\\\\\\\\\\. Mohammad Rezaei Fellowship of Pediatric Pulmonology

Dec 23, 2015

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  • Slide 1
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  • Slide 2
  • Mohammad Rezaei Fellowship of Pediatric Pulmonology
  • Slide 3
  • Respiratory distress Respiratory distress is a clinical impression
  • Slide 4
  • Respiratory failure inability of the lungs to provide sufficient oxygen (hypoxic respiratory failure) or remove carbon dioxide (ventilatory failure) to meet metabolic demands.
  • Slide 5
  • Respiratory failure Pao 2 < 60 torr with breathing of room air and Paco 2 > 50 torr resulting in acidosis, the patient's general state, respiratory effort, and potential for impending exhaustion are more important indicators than blood gas values.
  • Slide 6
  • Respiratory distress can occur in patients without respiratory disease, and respiratory failure can occur in patients without respiratory distress.
  • Slide 7
  • Respiratory failure Acute Chronic
  • Slide 8
  • The physiologic basis of respiratory failure determines the clinical picture. normal respiratory drive are breathless and anxious decreased central drive are comfortable or even somnolent.
  • Slide 9
  • The causes: conditions that affect the respiratory pump conditions that interfere with the normal function of the lung and airways
  • Slide 10
  • Respiratory Pump Dysfunction Decreased Central Nervous System (CNS) Input Head injury Ingestion of CNS depressant Adverse effect of procedural sedation Intracranial bleeding Apnea of prematurity Peripheral Nerve/Neuromuscular Junction Spinal cord injury Organophosphate/carbamate poisoning Guillian-Barre syndrome Myasthenia gravis Infant botulism Muscle Weakness Respiratory muscle fatigue due to increased work of breathing Myopathies/Muscular dystrophies
  • Slide 11
  • Airway/Lung Dysfunction Central Airway Obstruction Croup Foreign body Anaphylaxis Bacterial tracheitis Epiglottitis Retropharyngeal abscess Bulbar muscle weakness/dysfunction Peripheral Airways/Parenchymal Lung Disease Status asthmaticus Bronchiolitis Pneumonia Acute respiratory distress syndrome Pulmonary edema Pulmonary contusion Cystic fibrosis Chronic lung disease (eg, bronchopulmonary dysplasia)
  • Slide 12
  • Arterial gas composition depends on : the gas composition of the atmosphere the effectiveness of alveolar ventilation pulmonary capillary perfusion diffusion across the alveolar capillary membrane
  • Slide 13
  • Alveolar Gas Composition P A O2 = P I O2 (PCO2/R) P I O2 = (BP P H2O ). Fio2 P A O2 = [(BP P H2O ). Fio2] (PCO2/R)
  • Slide 14
  • Hypoventilation V A = V T. RR low respiratory rate and shallow breathing are both signs of hypoventilation.
  • Slide 15
  • Dead Space Ventilation Anatomical Physiological V D / V T = (P a CO2-P E CO2)/ P a CO2 = 0.33 Increases in decreased pulmonary perfusion: PHTN, hypovolemia, decreased cardiac output
  • Slide 16
  • Alveolar Ventilation V A = (V T -V D ). RR
  • Slide 17
  • Hypoventilation The Paco2 increases in proportion to a decrease in ventilation. Pao2 falls approximately the same amount as the Paco2 increases.
  • Slide 18
  • Hypoventilation The relationship between oxygenation and hypoventilation is complicated by the shape of the Hb-dissociation curve Because of the dissociation curve, a patient who exhibits alarming CO2 retention might have a near normal oxygen saturation.
  • Slide 19
  • 1. PO2 100 mm Hg= SpO2 of 97% 2. PO2 60mm Hg= SpO2 of90% When Paco2 increases from 40 to 70 mm Hg, a dangerous level of hypoventilation, might have a Pao2 that has decreased from 100 to 60 mm Hg and, therefore, maintain an oxygen saturation of 90%.
  • Slide 20
  • Thus: oximetry is not a sensitive indicator of the adequacy of ventilation. This is particularly true when a patient is receiving oxygen.
  • Slide 21
  • Lung/Airway Disease Diseases of the lung or airways affect gas exchange most often by disrupting the normal matching of V/Q or by causing a shunt. usually can maintain a normal Paco2 as lung disease worsens simply by breathing more. hypoxemia is the hallmark of lung disease
  • Slide 22
  • Ventilation-Perfusion Mismatch
  • Slide 23
  • hypoxemia due to V/Q mismatch & hypoxemia due to shunt administering Oxygen
  • Slide 24
  • Intrapulmonary Shunt
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  • Diffusion diffusion defects manifest as hypoxemia rather than hypercarbia. Examples : interstitial pneumonia, ARDS, Scleroderma, Pulmonary lymphangiectasia,
  • Slide 26
  • Monitoring a Child in Respiratory Distress and Respiratory Failure
  • Slide 27
  • Clinical Examination Clinical observation is the most important component of monitoring.
  • Slide 28
  • ABG & Oximetry ABG /CBG/ VBG Oximetry - Oximetry provides an invaluable and usually accurate measurement of oxygenation. - important to recognize its technical limitations
  • Slide 29
  • ConditionLimitation Dark skin pigment Anemia Causes inadequate signal Bright external light Motion Decreased perfusion Venous pulsations Severe right heart failure Tricuspid regurgitation Tourniquet or blood pressure cuff above site Results in low reading Abnormal hemoglobin concentration Methemoglobin Unreliable reading (tends to read 80% to 85% saturation regardless of actual saturation) SS hemoglobin Saturationaccurate, but hemoglobin dissociation curve shifted to right CarboxyhemoglobinSpuriously high saturation readings
  • Slide 30
  • Acute Respiratory Failure
  • Slide 31
  • ARF most common cause of cardiac arrest in children. When presented with a child who has: a decreased level of consciousness, slow/shallow breathing, or increased respiratory drive, the possibility of ARF should be considered
  • Slide 32
  • First: to assure adequate gas exchange and circulation (the ABCs). Oxygen Administration to maintain . If Ventilation is or appears to be inadequate .. Intubation ? Need ICU
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  • Chronic Respiratory Failure
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  • CRF is seen most commonly in children who have: Respiratory muscle weakness (muscular dystrophy, anterior horn cell disease) or severe chronic lung diseases (BPD, end- stage cystic fibrosis)
  • Slide 35
  • usually has an insidious onset Most children do not have dyspnea. PH normal or near normal, unless.. Recognizing need careful monitoring of children at risk for CRF
  • Slide 36
  • Disordered sleep Daytime hypersomnolence Morning headaches Altered mental status Increased respiratory symptoms Cardiomegaly Decreased baseline oxygenation CRF often presents first during sleep Develops an intercurrent illness, Fever
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