Transperitoneal exchanges of water and solutes in the fetus with gastroschisis. Experimental study in the chick embryo.

Aiming at testing the hypothesis that, in the foetus with gastroschisis (GX) peritoneal dialysis during antenatal bowel exposure to the amniotic fluid may induce some modifications of the internal environment, we have studied the composition of blood, amniotic fluid and allantoic fluid in a chick embryo model of GX. Intestinal loops were surgically eviscerated in 184 embryos on the 14th day of incubation and exposed to the mixture of both embryonal fluids until the 19th day (hatching expected at the 21th). Typical lesions of GX were present in half of the 94 survivors (n = 42). For comparison we used a control group of non-manipulated animals (n = 19) and a "sham" group of animals in which the operation was carried out only until umbilical manipulation but without bowel exposure (n = 22). Chicks with GX were smaller and slightly dehydrated as attested by clinical signs and had moderately increased hematocrit. They had significant hyperkaliaemia and slight decreases in serum Na and Cl. Urea, total protein and protein fractions were not modified. Taking into account the gradients for such substances existing between the dialysate (amino-allantoic mixture) and the embryonal blood, the changes observed, albeit slight, suggest that there was some evidence of dialysis through the peritoneum: lower Na and Cl concentrations in the dialysate than in blood, induced slight falls in serum Na and Cl whereas higher K concentration resulted in severe hyperkaliemia. The high levels of albumin in the chick amniotic fluid did not allow protein depletion and therefore total protein and its fractions remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)