Continuous fluid infusion per rectum compared with intravenous fluid infusion in pigs

Peripheral blood vessels in pigs are not easily accessible, making placement of intravenous catheters difficult. Alternative methods to intravenous administration of fluids, such as administering fluids via the rectum (proctoclysis), are warranted in pigs.

Administration of polyionic crystalloid fluids via proctoclysis results in hemodilution changes similar to intravenous administration. The objectives of this study were to evaluate the tolerance for proctoclysis in pigs and compare analytes before and after intravenous or proctoclysis therapy.

Six healthy, growing, academic institution-owned pigs.

Randomized, cross-over design clinical trial, with 3 treatments (control, intravenous, and proctoclysis) with a 3-day washout period. The pigs were anesthetized and jugular catheters were placed. A polyionic fluid (Plasma-Lyte A 148) was administered at 4.4 mL/kg/h during the intravenous and proctoclysis treatments. Laboratory analytes, including PCV, plasma, and serum total solids, albumin, and electrolytes were measured over 12 h at T₀ , T₃ , T₆ , T₉ , and T₁₂ . Effects of treatment and time on analytes were determined by analysis of variance.

Proctoclysis was tolerated by pigs. Albumin concentrations decreased during the IV treatment between T₀ and T₆ (least square mean of 4.2 vs 3.9 g/dL; 95% CI of mean difference = -0.42, -0.06; P = .03). Proctoclysis did not significantly affect any laboratory analytes at any time points (P > .05).

Proctoclysis did not demonstrate hemodilution similar to intravenous administration of polyionic fluids. Proctoclysis might not be an effective alternative to the intravenous administration of polyionic fluids in healthy euvolemic pigs.