Postoperative Management of Infants after Major Abdominal Surgery

Infants with intra-abdominal pathology often come to the operating room for repair or resection. Some of these infants have concurrent acute lung disease, often related to lack of surfactant production. This surfactant deficiency is associated with prematurity but is exacerbated by the  metabolic acidosis caused by the primary surgical disease process. Because of the lung disease, clinicians that are caring for the infant in the postoperative period may be hesitant to continue the fluid resuscitation that begins in the operating room. Many times, the lack of continued volume expansion is associated with the development of severe acidosis and hemodynamic instability. The response to this is often the use of vasoconstricting agents to increase the blood pressure and , in fact, this makes the clinical situation worse. In almost all of these cases the infant will fare better with judicious volume expansion than with fluid restriction, as this treats the primary problem, loss of intravascular volume into the bowel wall. Intravascular monitoring and determination of continued urinary output is usually required to determine whether appropriate volumes are being given.

The volume of fluid that is given to these infants is important. The quality of the fluid that is administered is equally important and consideration must be given to the defects in renal function that are present in the newborn. Infants have difficulty clearing free water, sodium and chloride. Saline, with an excess of sodium and chloride relative to the infant's serum levels will rapidly produce high levels of sodium and chloride, sometimes resulting in a secondary acidosis. This secondary acidosis - hyperchloremic metabolic acidosis - is a common cause of refractory disturbances in patients that are being resuscitated.

So, for infants that have had intra-abdominal catastrophes, the volume resuscitation must continue through transport and into the postoperative period. The use of saline as the sole IV solution for this resuscitation will produce a secondary acidosis and exacerbate the primary disease process. Solutions such as ringers lactate are more hypotonic and can be applied to the situation without the development of secondary metabolic disturbances.