Respiratory gas exchange in response to fat-free parenteral nutrition: A comparison after thoracic or abdominal surgery in newborn infants

Abstract

Thoracic surgery is known to cause a postoperative respiratory failure because of the mechanical problems following chest wall disruption and/or diaphragmatic dysfunction. This study was to verify whether the fat-free intravenous nutritional support of neonates who underwent thoracic surgery could lead to a CO2 production exceeding the patients' respiratory reserves. Respiratory gas exchange and alveolar ventilation were obtained by indirect calorimetry and continuous recordings of transcutaneous PO2 and PCO2. These noninvasive measurements were compared at the same age of 7 +/- 1 days between a group of 7 newborn infants (mean +/- SEM: 3.09 +/- 0.14 kg, 39 +/- 1 weeks) after thoracic surgery versus a group of 8 newborn infants (2.88 +/- 0.17 kg, 37 +/- 1 weeks) after abdominal surgery. The intravenous macronutrient support was the same between both groups: 14 g/kg/d of glucose, 2 g/kg/d of amino acids, 250 kJ/kg/d of energy. One week after surgery, the global metabolic rate (195 kJ/kg/d) was not increased, and comparable between both groups. We documented that early after thoracic surgery, the ventilatory compensation required to handle the CO2 production (6.7 +/- 0.2 mL/kg/min) associated with a positive energy balance (45 +/- 8 kJ/kg/d) was effective.