Research Article: Effect of preconditioning and postoperative hyperbaric oxygen therapy on colonic anastomosis healing with and without ischemia in rats 1

Date Published: June 22, 2020

Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia

Author(s): José Luiz Fontoura-Andrade, Leonardo Mendes Pinto, Fabiana Pirani Carneiro, João Batista de Sousa.


To investigate the effect of hyperbaric oxygen therapy on colonic anastomosis healing with and without ischemia in rats.

Forty female rats underwent segmental resection of 1 cm of the left colon followed by end-to-end anastomosis. They were randomly assigned to four groups (n=10 each), a sham group; two groups were submitted to Hyperbaric Oxygen therapy (HBOT) with and without induced ischemia and the induced ischemia group without HBOT. The HBOT protocol evaluated was 100% O2 at 2.4 Atmosphere absolute pressure (ATA) for 60 minutes, two sessions before as a preconditioning protocol and three sessions after the operation. Clinical course and mortality were monitored during all experiment and on the day of euthanasia on the fourth day after laparotomy. Macroscopic appearance of the abdominal cavity were assessed and samples for breaking strength of the anastomosis and histopathological parameters were collected.

There was no statistically significant difference in mortality or anastomosis leak between the four experimental groups. Anastomosis breaking strength was similar across groups.

The HBOT protocol tested herein at 2.4 ATA did not affect histopathological and biomechanical parameters of colonic anastomotic healing, neither the clinical outcomes death and anastomosis leak on the fourth day after laparotomy.

Partial Text

Complications of colorectal anastomosis have a relevant incidence and are often severe. In addition to their contribution to an undesirably high mortality rate, further implications include prolonged hospital stay, substantially increased treatment cost, and perpetuation of functional sequelae. The most fearsome complications are infection and anastomotic dehiscence1 . Several drugs have been investigated in the search to reduce the incidence of these complications. In 2014, Oines et al .2 published a meta-analysis reporting experiments with 56 therapeutic agents, of which only seven met their inclusion criteria: iloprost, tacrolimus, erythropoietin, growth hormone, broad-spectrum matrix metalloproteinase inhibitors, insulin-like growth factor-1, and hyperbaric oxygen therapy (HBOT). These therapeutic agents experimentally increased the pressure required for disruption of colon anastomosis.

This study was approved by the Hospital das Forças Armadas Animal Care and Use Committee under the registration number 60550.008623/2016-00. The “Animal Research: Reporting in vivo experiments” (ARRIVE) guidelines were followed in designing, conducting, and reporting the experiment13 , 14 . All procedures with animals were carried out in accordance with the UK Animals (Scientific Procedures) Act, 1986, and associated guidelines and EU Directive 2010/63/EU and International Guiding principles for biomedical research involving animals by Council for International Organization of Medical Sciences-CIOMS.

The hyperbaric protocol of pre and pos intervention sessions at 2.4 ATA failed to produce statistically significant differences, especially in the clinical endpoint of anastomosis leak.

Based on analysis of anastomotic breaking strength and histopathological features, the hyperbaric oxygen therapy protocol at 2.4 ATA two daily sessions prior to operation as preconditioning and four sessions after it did not influence colonic anastomosis healing on the fourth day after operation.




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