Abstract
Objectives: To identify factors involved in reno-pulmonary interactions during mechanical ventilation of helthy lungs. Materials and Methods: The study included a total of 25 healthy domestic piglets with an average weight of 22.7kg (SD 2.17).
The animals were divided into three groups based on different strategies of ventilation: Group A (n=5); spontaneously breathing piglets; group B (n=10) the animals ventilated 12 hours with tidal volume of 6ml.kg-1 and group C (n=10) with animals ventilated 12 hours with tidal volume 10ml.kg-1. Clinical monitoring , as well as laboratory tests, were performed for all groups at baseline and then at 1 hour and 12 hours for groups B and C.
Ventilation indices, systemic blood pressure, urine output, laboratory analysis of urine and serum, creatinine clearance, glomerular filtration index, fractional excretion of sodium, free water clearance, u-K/u-Na ratio and tissue samples were recorded. The data obtained were statistically analysed and values having P<0.05 were considered statistically significant.
Results: Lower creatinine clearance and renal indices were seen group B (P< 0.05) and group C (P<0.001) at 1 hour, and a difference in one-hour diuresis for group C (P< 0.01) when compared to group A. At 12 hours, there was a further reduction in creatinine clearance and renal indices for group B (p< 0.05) and group C (p< 0.01) as well as urine output in the group B (p< 0.01).
The lung mechanics and blood circulation were not significantly influenced. Conclusions: The study showed a causal relationship between renal dysfunction and positive pressure mechanical ventilation with respect to tidal volume and time.