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A 45-year-old male is brought to the emergency department after hydrochloric acid ingestion at his
workplace. The physical examination is notable for respiratory distress, diffuse crackles, and tachycardia.
Jugular venous pressure is normal. The oropharynx shows no significant lesions. PaO2 on 100%
nonrebreather is 56. A chest radiogram shows diffuse bilateral alveolar infiltrates. He is emergently
intubated. The patient weighs 70 kg. Which of the following are appropriate initial settings for
mechanical ventilation?
A. Tidal volume 420 mL, respiratory rate 24, FIO2 100%, PEEP 5
B. Tidal volume 700 mL, respiratory rate 20, FIO2 100%, PEEP 5
C. Tidal volume 420 mL, respiratory rate 24, FIO2 50%, PEEP 5
D. Tidal volume 700 mL, respiratory rate 20, FIO2 50%, PEEP 5
E. Tidal volume 840 mL, respiratory rate 20, FIO2 100%, PEEP 5
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Fi02 has to be the lower to reduce oxygen toxicity...so C or D
volumen ventilation with small tidal volumens are better ie: pt is 70 kg...for anesthesia is 10 ml per kg, but for ARDS can be less as the rate of 6 ml/kg that give us 420 ml....so A or C
So i will say C
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very confusing quest. may be A or C.
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D. Tidal volume 700 mL, respiratory rate 20, FIO2 50%, PEEP 5
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elba..very nice...ur concepts were quite right...the only thing u missed out is....she is already on 100% oxygen and her Pao2 is 56...u cant make it less...anyway..welldone!
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The answer is A.
This patient presents with acute respiratory distress syndrome (ARDS), and the question asks for the
most appropriate initial settings for the mechanical ventilator. Traditional settings for the ventilator are a
tidal volume of 10 to 12 mL/kg; however, a trial published in the New England Journal of Medicine by the
Acute Respiratory Distress Syndrome Network compared this approach with a lung protective strategy
using lower tidal volume ventilation. The lower tidal volume arm used initial settings of 6 mL/kg for tidal
volume and adjusted the tidal volume down as needed to keep the plateau pressure below 30. Patients
in the lower tidal volume group had decreased mortality. Thus, the most appropriate tidal volume is 70
kg x 6 mL/kg = 420 mL. Initial FIO2 should be 100% in light of the patient's profound hypoxemia before
intubation.
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Good qand good explanation
In adults volume based ventilation is used. So careful to start with tidal volumes of 6ml/kg and then work up but in children and neonates the story is different, the starrategy is
Pressure guided, in childrena nd neonates we work with pressures. An initial starting point would be pressures of 18-20 of PIP and 4-5 of PEEP, inspiratory time of 0.36 to 0.4, Rate of 60/min and work on ventilator as guided by blood gases
Both very high pressures and high volumes cause barotrauma to lungs. We should aim to lessen this as much as we can.
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