Tutorial: Pulmonary Function--Dr. Bhutani Clinical Case 695 g male neonate with RDS, treated with surfactant and on ventilatory support @ 18 hours age: Settings: 18 / 5 cm H 2 0 x 45 breaths / min; FiO 2 = 0.65 Driving Pressure: 18-5 = 13 cm H 2 0 Arterial Gas: pH = 7.3; PaO2 = 74; PaCO2 = 55 mmHg Is this baby a candidate for
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Tutorial: Pulmonary Function--Dr. Bhutani
Clinical Case695 g male neonate with RDS, treated with surfactant and on ventilatory support @ 18 hours age:
Settings: 18 / 5 cm H20 x 45 breaths / min; FiO2 = 0.65
Is this baby a candidate for permissive hypercapnia?
Normocapnia varies?
• Maternal: 32 - 34 mmHg (progesterone effect)
• Fetal: 40 - 42 mmHg
• At birthing: 45 - 65 mmHg
• First day : 34 mmHg (progesterone effect)
• After first week : 35 - 42 mmHg
• Term PCA: 35 - 42 mmHg (RR = 40-60/min)
• 52 wks PCA: 35 - 42 mmHg (RR = 20-30/min)
Strategies to Prevent Non-Permissive Hypercapnia
• Define optimum PaCO2 levels
• Level to at which you will intervene• Level to at which you will wean
• Ventilate at optimal FRC
• Continuous monitoring of tidal volume
• Use least pressure for maximal tidal volume
• Facilitate spontaneous breathing
• Consider “dual wean” of driving pressures
• Consider pseudo-adaptive strategies
Alveolar Algebra: Ventilation
• Alveolar Ventilation inversely correlated to PaCO2
• Alveolar Ventilation is (VT-VD) x rate• Provided dead space is constant: proportional
changes in VT or rate will lead to proportional changes in alveolar ventilation and PaCO2.
Based on Pulmonary Gas Law: in a steady state, when inspired CO2 is negligible, then PACO2 = 863 (VCO2 / VA); where, VCO2 is CO2 production; PACO2 is partial pressure of carbon dioxide; 863 is body temp. x std. pressure / standard temperature ( 310 X 760/273 = 863 )
Clinical Case695 g male neonate with RDS, treated with surfactant and on ventilatory support and is now about 18 hours age and has stable vital signs, normotensive and is normoglycemic:
Settings: PIP:18 cm H20; PEEP: 5 cm H20; SIMV: 45 br / min;
Clinical Case695 g male neonate with RDS, treated with surfactant and on ventilatory support and is now about 18 hours age and has stable vital signs, normotensive and is normoglycemic:
Settings: PIP:18 cm H20; PEEP: 5 cm H20; SIMV: 45 br / min;
Clinical Case695 g male neonate with RDS, treated with surfactant and on ventilatory support and is now about 18 hours age and has stable vital signs, normotensive and is normoglycemic:
Settings: PIP:18 cm H20; PEEP: 5 cm H20; SIMV: 45 br / min;