Chronic Respiratory Failure in a Neonate

A 2.5-month-old, 3.5-kg, male infant with bronchopulmonary dysplasia was intubated and received oxygen (FIO₂ = 0.3). He presented for cryoablation for proliferative retinopathy (see Chapter 59 , Chapter 60 , and Chapter 76 ). After the patient was transported to the operating room, blood gas analysis showed pHa = 7.27, PaCO₂ = 65 mm Hg, BE = 3 mEq/L, bicarbonate = 29, and PaO₂ = 35 mm Hg. Anesthesia was induced, and ventilation was controlled, with a tidal volume = 60 mL, peak inspiratory pressure = 25 cm H₂ O, positive end-expiratory pressure = 4 cm H₂ O, respiratory rate = 40 breaths/min, no inspiratory pause, and FIO₂ = 0.3. Repeat blood gas determinations showed pHa = 7.36, PaCO₂ = 50 mm Hg, BE = 3 mEq/L, bicarbonate = 28, and PaO₂ = 48 mEq/L.

The mild metabolic alkalosis of the first analysis is compatible with compensation for chronic respiratory failure. The high PaCO₂ value represented hypoventilation during transport. Appropriate selection of the ventilator settings returned the PaCO₂ to a value more typical for a neonate with bronchopulmonary dysplasia with

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