Effects of hyperbaric oxygen therapy on the liver after injury caused by the hepatic ischemia-reperfusion process

Influence of intraoperative oxygen content on early postoperative graft dysfunction in living donor liver transplantation: A STROBE-compliant retrospective observational study

The aim of the present study was to investigate the role of intraoperative oxygen content on the development of early allograft dysfunction (EAD) in patients undergoing living donor liver transplantation (LDLT).This retrospective review included 452 adult patients who underwent elective LDLT. Our study population was classified into 2 groups: EAD and non-EAD. Arterial blood gas analysis was routinely performed 3 times during surgery: during the preanhepatic phase (ie, immediately after anesthetic induction); during the anhepatic phase (ie, at the onset of hepatic venous anastomosis); and during the neohepatic phase (ie, 1 hour after graft reperfusion). Arterial oxygen content (milliliters per deciliters) was derived using the following equation: (1.34 × hemoglobin [gram per deciliters] × SaO2 [%] × 0.01) + (0.0031 × PaO2 [mmHg]).The incidence of EAD occurrence was 13.1% (n = 59). Although oxygen contents at the preanhepatic phase were comparable between the 2 groups, the oxygen contents at the anhepatic and neohepatic phases were lower in the EAD group than in the non-EAD group. Patients with postoperative EAD had lower oxygen content immediately before and continuously after graft reperfusion, compared to patients without postoperative EAD. After the preanhepatic phase, oxygen content decreased in the EAD group but increased in the non-EAD group. The oxygen content and prevalence of normal oxygen content gradually increased during surgery in the non-EAD group, but not in the EAD group. Multivariable analysis revealed that oxygen content during the anhepatic phase and higher preoperative CRP levels were factors independently associated with the occurrence of EAD (area under the receiver-operating characteristic curve: 0.754; 95% confidence interval: 0.681-0.826; P < .001 in the model). Postoperatively, patients with EAD had a longer duration of hospitalization, higher incidences of acute kidney injury and infection, and experienced higher rates of patient mortality, compared to patients without EAD.Lower arterial oxygen concentration may negatively impact the functional recovery of the graft after LDLT, despite preserved hepatic vascular flow. Before graft reperfusion, the levels of oxygen content components, such as hemoglobin content, PaO2, and SaO2, should be regularly assessed and carefully maintained to ensure proper oxygen delivery into transplanted liver grafts.

Hyperbaric Oxygen Therapy in Liver Diseases

Hyperbaric oxygen therapy (HBOT) is an efficient therapeutic option to improve progress of lots of diseases especially hypoxia-related injuries, and has been clinically established as a wide-used therapy for patients with carbon monoxide poisoning, decompression sickness, arterial gas embolism, problematic wound, and so on. In the liver, most studies positively evaluated HBOT as a potential therapeutic option for liver transplantation, acute liver injury, nonalcoholic steatohepatitis, fibrosis and cancer, especially for hepatic artery thrombosis. This might mainly attribute to the anti-oxidation and anti-inflammation of HBOT. However, some controversies are existed, possibly due to hyperbaric oxygen toxicity. This review summarizes the current understandings of the role of HBOT in liver diseases and hepatic regeneration. Future understanding of HBOT in clinical trials and its in-depth mechanisms may contribute to the development of this novel adjuvant strategy for clinical therapy of liver diseases.

Effects of hyperbaric therapy on liver morphofunctional of rabbits (Oryctolagus cuniculus) after hind limb ischemia-reperfusion injury

AIM

The objective of this research was to study and to prove the effectiveness of hyperbaric oxygen therapy (HBOT) starting time on liver morphofunctional changes after ischemia-reperfusion in the hind limb of rabbits.

MATERIALS AND METHODS

This research used a complete randomized design with 4 groups and 6 repetitions on each. After 6 h artery femoral is ligation, reperfusion was performed for 100 min (G1), HBOT for 90 min after 10 min reperfusion (G2), 10 min reperfusion (G3), and HBOT 90 min after 60 min reperfusion (G4). Then, all of the rabbits were sacrificed. The liver and blood were taken for histopathological changes examination as well as for measuring the level of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The statistical test using Kruskal-Wallis and Mann-Whitney showed that the score of degeneration, necrosis, and portal inflammation in groups without HBOT (G1 and G3) were not significantly different, as well as in group with HBOT (G2 and G4) (p>0.05). However, the scores of histopathological changes in G1 and G3 were significantly different from those in G2 and G4 (p<0.05). The levels of AST and ALT in the groups without hyperbaric therapy (G1 and G3) were not significantly different from those in the groups treated with hyperbaric therapy (G2 and G4) (p>0.05).

RESULT

Hind limb ischemia injury reperfusion can trigger damage for liver morphology, but not lead to liver dysfunction. Reperfusion can trigger increased activity of neutrophils, while neutrophil infiltration in the organ will lead to dysfunction. HBOT can inhibit the activity of neutrophils and the dysfunction of organs caused by ischemic reperfusion.

CONCLUSION

HBOT for 90 min, both 10 and 60 min after the reperfusion, can protect hepatocytes from damage.

Application of hyperbaric oxygen in liver transplantation

In recent years, hyperbaric oxygen (HBO) has been used in the treatment of a lot of diseases such as decompression sickness, arterial gas embolism, carbon dioxide poisoning, soft tissue infection, refractory osteomyelitis, and problematic wound, but little is known about its application in liver transplantation. Although several studies have been conducted to investigate the protective effects of HBO on liver transplantation and liver preservation, there are still some controversies on this issue, especially its immunomodulatory effect. In this short review, we briefly summarize the findings supporting the application of HBO during liver transplantation (including donors and recipients).