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cyanosis - Evaluation of the Cyanotic Infant Bill Lefkowitz...

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Unformatted text preview: Evaluation of the Cyanotic Infant Bill Lefkowitz 16 NOV 2000 Outline Outline Cyanosis ­ define and describe Terms (PaO2 v SaO2 v CaO2) Differential of cyanosis The hyperoxia test A few etiologies Take home points Evaluation and intervention Flowchart Cyanosis Cyanosis 3g/dL deoxyhemoglobin Low flow areas with increased oxygen extraction have more deoxyhemoglobin High flow areas with less extraction should not have enough deoxyhemaglobin to appear cyanotic Under normal circumstances you should not be able to extract enough O2 to have 3g/dL deoxyhemoglobin running through the tongue and gums (lips OK when cold) Cyanosis Acro v Central Cyanosis Acro v Central Acrocyanosis part of normal transition may last 72hr beware APGAR of 10 hypoperfused severe anemia Cyanosis Cyanosis Cyanosis Cyanosis is dependent on HCT and % Sat Florescent light makes cyanosis hard to see. Except in the extreme, cyanosis is not obvious Any question, check a pulse ox C yanosis 100 90 80 70 % Saturation 60 50 40 30 20 10 0 0 20 40 HCT 60 80 RA v. O2 ­ Saturations RA v. O Terms Terms PaO2 Arterial Oxygen Pressure Measured on an ABG machine Oxygen dissolved in plasma 0.003 ml O2/mmHg/dl plasma SaO2 Percent Oxygen Saturation Measured by saturation monitor (pulse­Ox) ~1.34ml O2/g Hb PaO2 and SaO2 PaO Oxyhemoglobin dissociation Oxyhemoglobin dissociation Terms Terms CaO2 Oxygen Content of the blood bound to Hb + dissolved in plasma 100% saturated Hb 18g/dl 90 mmHg in plasma = [1.0*18*1.34]+[0.003*90] = [24]+[0.25] Physiologically, saturations much more important to oxygen content (0.003*600 = 1.8) CaO2 Samples CaO NORMAL 95%, Hb 18 PaO2 85 [.95*18*1.34]+[0.003*85] [23]+[0.25]=23 CaO2 Samples CaO HYPEROXIA 100%, Hb 18 PaO2 600 [1.0*18*1.34]+[0.003*600] [24]+[1.8]=26 CaO2 Samples CaO ANEMIA 95%, Hb 10 PaO2 85 [.95*10*1.34]+[0.003*85] [13]+[0.25]=13 CaO2 Samples CaO ANEMIA­ HYPEROXIA 100%, Hb 10 PaO2 600 [1.0*10*1.34]+[0.003*600] [13]+[1.8]=15 CaO2 Samples CaO CCHD 75%, Hb 18 PaO2 40 [.75*18*1.34]+[0.003*40] [18]+[0.12]=18 CaO2 Samples CaO CCHD­ANEMIA 75%, Hb 10 PaO2 40 [.75*10*1.34]+[0.003*40] [10]+[0.12]=10 Differential of cyanosis Differential of cyanosis 3g of deoxyhemoglobin/dL (cyanosis) ­ Not enough oxygen in ­ Oxygen “mal­absorption” ­ Too much oxygen out Not enough oxygen in Not enough oxygen in Apnea Diffusion barrier neurologic and pharmacologic causes RDS, aspiration, pneumonia Obstruction pneumothorax, head position Oxygen “mal­absorption” Oxygen “mal­absorption” Shunting lesions cardiac non­cardiac (like PPHN) Hematologic methemoglobinemia carboxyhemoglobinemia Too much oxygen out Too much oxygen out High oxygen consumption sepsis low flow, high extraction acrocyanosis hyperviscosity/polycythemia extravasated (ie bruising) What is the Hyperoxia test? Hyperoxia Test Hyperoxia Test Infant on Room Air, get ABG Infant on 100% oxygen, get ABG PaO2 unchanged = fixed shunt = CCHD Max PaO2 <100 = CCHD Max PaO2 >200 = No CCHD Hyperoxia Test Hyperoxia Test Giving 100% overcomes the diffusion barrier Normal ­­­­­­­­­­­ Bad Lungs ­­­­­­­ (diffusion barrier) Shunt ­­­­­­­­­­­­­ Shunt with Bad ­­ Lungs Hyperoxia Test Hyperoxia Test Hyperoxia Proper Hyperoxia CPAP Hyperoxia hyper­ ventilation Hyperoxia Test Hyperoxia Test Jones: 1976 8/109 with CCHD had PaO2 > 100mmHg 7/23 without CCHD (bad RDS etc) had PaO2 < 150mmHg HLHS > 300mmHg TGA, TAPVR > 200mmHg Don’t be fooled by early high PaO2s Hyperoxia Test Hyperoxia Test Don’t do the room air part Looking for minimal PaO2 change from 21% to 100% fiO2 Hyperoxia test developed pre pulse­ox With pulse­ox you can tell when PaO2s are not changing despite big changes in fiO 2 (for sats that are between 70 and 95%) Probably the norm to have some degree of lung disease at the time of the test anyway Information needed Information needed Clinical appearance Pulses/perfusion differential, delayed Pulse­Ox/ABG “comfortably tachypneic and blue” pre and post ductal, max PaO2 Auscultation S2, Murmur Information needed Information needed CXR heart shapes snowman = TAPVR1 boot = pulm atresia, TOF, tricuspid atresia egg on string = TGA pulmonary vascularity EKG axis increased or decreased forces TAPVR1 TAPVR Snowman 50% type 1 50% snowman venous connection at VV to SVC TOF TOF Boot shape RVH lifting apex loss of PA knob TGA TGA Egg on a string alignment of PA and Ao narrows the mediastinum The 6 T’s The 6 T’s Total Anomalous Pulmonary Veins Tetrology of Fallot Tricuspid Atresia Transposition Truncus Arteriosus Total Acardia Normal Anatomy Normal Anatomy normal PPHN ­ PDA shunting PPHN ­ PDA shunting Pre and post ductal sats Head and coronaries get well oxygenated blood Normal Anatomy Normal Anatomy normal PPHN ­ PFO shunting PPHN ­ PFO shunting Head and coronaries get hypoxemic blood TAPVR TAPVR TAPVR TAPVR Type 1 (supracardiac) 50% with snowman can have UE<LE sats Type 2 (cardiac) Type 3 (infracardiac) all can obstruct, infracardiac almost always does Normal Anatomy Normal Anatomy normal TOF TOF Overriding Aorta VSD PS RVH Normal Anatomy Normal Anatomy normal Tricuspid Atresia Tricuspid Atresia TGA TGA normal TGA ­ no PPHN TGA ­ no PPHN Comfortably tachypneic (usually big) child with sats in the 50s on room air or oxygen TGA ­ with PPHN TGA ­ with PPHN TGA and TAPVR type 1 can present with higher sats in then lower extremities than the upper extremities Normal Anatomy Normal Anatomy normal Truncus Arteriosus Truncus Arteriosus Normal Anatomy Normal Anatomy normal Total Acardia Total Acardia Poor prognosis, consider DNR Flow diagram Flow diagram There are bad acyanotic lesions There are bad cyanotic lesions A ductal dependent lesion is one that depends on the ductus to get adequate blood flow to the pulmonary and systemic circuits, or provide mixing PS CoA TGA Summary and Take Home Points Summary and Take Home Points Check a pulse ox (murmur w/u, suspicion) murmur w/u (š Sx) Pulse­Ox, EKG, 4­point BPs Don’t be fooled by a reassuring hyperoxia test if suspicion remains high If you think you have a ductal dependent lesion, start prostin (don’t be afraid of prostin) Summary and Take Home Points Summary and Take Home Points If a baby presents in shock in the first week (or two) of life think sepsis & ductal dependant lesions & CAH Cyanosis w/u includes antibiotics Make sure your pharmacy carries prostin Don’t be afraid to use it Know how to mix it! QUESTIONS? ...
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