The centrilobular liver cell necrosis observed in hypoxic hepatitis is generally attributed to failure of hepatic blood perfusion. Accordingly, this injury of the liver is commonly recognized under the terms "shock liver" or "ischemic hepatitis." During a 10-year period, 142 episodes of hypoxic hepatitis were consecutively identified in the intensive care unit of a general hospital, and the clinical, biological, and hemodynamic parameters were prospectively collected on individual files. We conducted the current study to assess retrospectively the role of the hemodynamic mechanisms of tissue hypoxia: ischemia, passive venous congestion, and hypoxemia. Among the 142 episodes of hypoxic hepatitis, 138 were separated in 4 main groups based on clinical features: decompensated congestive heart failure (80 cases), acute cardiac failure (20 cases), exacerbated chronic respiratory failure (19 cases), and toxic/septic shock (19 cases). An elementary hemodynamic evaluation, including blood pressure, central venous pressure, and arterial blood gas analysis, was carried out in every episode and a more complete hemodynamic assessment through pulmonary artery catheterization was performed in 61 episodes. The hemodynamic mechanisms responsible for hypoxic hepatitis were different in the 4 groups. In congestive heart failure and acute heart failure, the hypoxia of the liver resulted from decreased hepatic blood flow (ischemia) due to left-sided heart failure and from venous congestion secondary to right-sided heart failure. In chronic respiratory failure, liver hypoxia was mainly due to profound hypoxemia. In toxic/septic shock, oxygen delivery to the liver was not decreased but oxygen needs were increased, while the liver was unable to use oxygen properly. In all conditions underlying hypoxic hepatitis, except toxic/septic shock, a shock state was observed in only about 50% of the cases. Therefore, the expressions "shock liver" or "ischemic hepatitis" are misleading and should be replaced by the more general term "hypoxic hepatitis."

Out of a prospective series of 142 consecutive episodes of hypoxic (ischemic) hepatitis (HH), we identified 17 episodes associated with an acute exacerbation of chronic respiratory failure (CRF) without left cardiac failure. In the aim to evaluate the role of arterial hypoxemia in the pathogenesis of HH associated with respiratory failure, these 17 episodes of HH (study group) were hemodynamically compared with a control group of 17 episodes of HH associated with congestive heart failure (CHF) (control group 1) and a group of 16 episodes of acute respiratory failure (ARF) not complicated by HH (control group 2). Arterial hypoxemia was significantly more severe in the study group (

Cardiac and circulatory failure are the main causes of hypoxic hepatitis. In a prospective study of 142 cases of hypoxic hepatitis collected during a 10-year period, we encountered two cases resulting from extreme arterial hypoxemia without congestive heart failure, cor pulmonale, or circulatory failure. Both patients were morbidly obese women admitted to the intensive care unit for carbonarcosis. Oxygen arterial saturation was very low, less than 35% in both patients, but there was no history of cardiac or respiratory failure and no clinical evidence of circulatory failure. Cardiac function, evaluated by isotopic scintigraphy, was normal. After the episode of hypoxic hepatitis, a diagnosis of obstructive sleep apnea was made clinically and confirmed by performing nocturnal oximetry, which showed multiple episodes of oxygen desaturation in both patients. Polysonography could be performed in one case and was typical of obstructive sleep apnea. Liver ischemia is the main mechanism leading to hypoxic hepatitis. More recently, the role of passive congestion of the liver has been emphasized. Arterial hypoxemia, however, is generally considered to be a minor factor. Our two cases support the hypothesis that severe arterial hypoxemia may lead to hypoxic hepatitis even in the absence of cardiac and circulatory failure.

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