Animal model of continuous peritoneal lavage with vacuum peritoneostomy

Haemodynamics Imaging of Swine Segmental Kidney Artery Using Duplex Doppler Technique

Introduction

The aim of the study was to assess the usefulness of duplex Doppler to objectify swine renal arterial flow in physiological conditions. The pig kidney was selected for its morphological similarities to the human and for the results therefore offering data to wider research.

Material and Methods

Six White Large x Landrace sows, of 48.5-53 kg b.w. were used. Vascular flow parameters were acquired with a convex probe USG device with a duplex Doppler function using pulsed waves (frequency range of 5-7.5 MHz). Segmental kidney arterial flow was measured.

Results

The RI values were within the 0.57 (min) to 0.6 (max) range, x _RI was 0.58 (±0.014), and the SD²value was 0.0002. The PI index values ranged from 1.21 (min) to 1.3 (max), and x _PI was 1.24 (±0.035). The value of SD²was 0.00123. In the S/D index, the results fell between 2.2 (min) and 2.49 (max), with x _S/D of 2.29 (±0.117). The value of variance SD²was 0.0139. A double analysis of correlation between indices showed this to be almost certain and highly positive as confirmed by high correlation coefficients: r _{RI & PI} 0.857, rho _{RI & PI} 0.739, r _{RI & S/D} 0.930, rho _{RI & S/D} 0.941, r _{PI & S/D} 0.913, and rho _{PI & S/D} 0.754. The segmental kidney arterial flow spectrum evinced falls in PSV and PSV/LDV ratio, also noticed in the filling of the spectral window, comparing the renal to an interlobar artery.

Conclusion

Swine were selected because of renal anatomical and haemodynamic similarity to humans. The most relevant values and indices approximated those in humans. The study anaesthetic protocol had a minor influence on the average RI, PI, and S/D indices.

Continuous peritoneal lavage with vacuum peritoneostomy: an experimental study

OBJECTIVE

Despite advances in diffuse peritonitis treatment protocols, some cases develop unfavorably. With the advent of vacuum therapy, the use of laparostomy to treat peritonitis has gained traction. Another treatment modality is continuous peritoneal lavage. However, maintaining this technique is difficult and has been associated with controversial results. We propose a new model of continuous peritoneal lavage that takes advantage of the features and benefits of vacuum laparostomy.

METHOD

Pigs (Landrace and Large White) under general anesthesia were submitted to laparostomy through which a multiperforated tube was placed along each flank and exteriorized in the left and lower right quadrants. A vacuum dressing was applied, and intermittent negative pressure was maintained. Peritoneal dialysis solution (PDS) was then infused through the tubes for 36 hours. The stability of peritoneostomy with intermittent infusion of fluids, the system resistance to obstruction and leakage, water balance, hemodynamic and biochemical parameters were evaluated. Fluid disposition in the abdominal cavity was analyzed through CT.

RESULTS

Even when negative pressure was not applied, the dressing maintained the integrity of the system, and there were no leaks or blockage of the catheters during the procedure. The aspirated volume by vacuum laparostomy was similar to the infused volume (9073.5±1496.35 mL versus 10165±235.73 mL, p=0.25), and there were no major changes in hemodynamic or biochemical analysis. According to CT images, 60 ml/kg PDS was sufficient to occupy all intra-abdominal spaces.

CONCLUSION

Continuous peritoneal lavage with negative pressure proved to be technically possible and may be an option in the treatment of diffuse peritonitis.