Culafić Dj, Perisić M, Rebić P
Department of Gastroenterology and Hepatology, Clinical Centre of Serbia, Belgrade.
Srp Arh Celok Lek. 2000 Jul-Aug;128(7-8):271-5.
Hepatopulmonary syndrome (HPS) is defined by liver disease, hypoxaemia, increase of alveolar-arterial gradient, when inhaling room air, and intrapulmonary vascular dilatation. Pathoanatomical substrate of intrapulmonary vascular dilatation consists of dilated precapillary network, direct arterio-venous communication and dilated pleural blood vessels, "pleural spiders" [2]. Recently, hepatopulmonary syndrome gained clinical significance. Deterioration of arterial oxygenation in patients with liver disease indicates a very poor prognosis, because of which there are suggestions to classify hepatopulmonary syndrome as a new indication of liver transplantation [4].
The aim of the study was to examine the clinical and pathogenetic significance of intrapulmonary shunts in the development of respiratory disorders, and determination of correlation between intrapulmonary shunts and clinical, biochemical parameters in patients with liver cirrhosis.
In a prospective study over the period 1996-1999, we observed 50 patients with liver cirrhosis who were examined and treated at the Department of Gastroenterology and Hepatology of the Clinical Centre of Serbia in Belgrade. Hepatic examinations were based on medical history, physical examination, laboratory tests, ultrasound, duplex Doppler ultrasound, and histopathological findings. Hepatic failure was classified into 3 stages according to Child's classification. In this study we used 2 groups of pulmonary functional tests: analysis of arterial blood gas exchange and ventilation tests (spirometry, flow-volume curve and body pletismography). Arterial blood gas analysis was performed in supine and sitting positions while inhaling room air and after 15 min of inhaling hyperoxic mixture.
Patients were classified according to the generally accepted Child's classification into 3 stages: Sixteen patients (32%) were in Child's A stage, 20 patients (40%) in Child's B stage, and 14 (28%) in stage Child's C. HPS was diagnosed in 9 (18%) patients with liver cirrhosis. The majority of patients with HPS (6) were in Child's C stage, while the other 3 patients were in Child's B stage. Biochemical parameters were considerably worse in patients with shunts in comparison to those without shunts. However, t-test shoved no significant difference. Hypoxaemia caused by intrapulmonary arterio-venous shunt in supine position was found in 7 (14%) patients. Mean value of PaO2 was 8.72 kPa (SD = 1.02). Hypoxaemia caused by arterio-venous shunt in sitting position was found in 9 (18%) patients. The mean PaO2 value was 7.41 kPa, SD = 1.81. Orthodeoxia was confirmed in all patients with intrapulmonary shunt. Hypoxaemia without shunt in supine position was found in 18 (36%) patients, while 12 (24%) patients had hypoxaemia without shunt in sitting position. Comparing groups of patients with shunt and without shunt in supine position, we found a borderline statistically significant difference in PaO2 values (p = 0.057, t-test). In sitting position the difference in PaO2 values between these groups was statistically very significant (p = 0.001, t-test).
It is supposed that approximately 50% of patients with indication for liver transplantation have some form of arterial oxygenation disorder and 13-47% of these patients may have HPS [6, 7]. In our study, HPS was diagnosed in 18% of patients. We explain this high incidence by the fact that our study included the patients with advanced liver cirrhosis (stages Child's B and C). In studies performed up to date, there was neither correlation between biochemical liver function parameters and intrapulmonary shunts, nor any strong relation between severity of hepatic failure and degree of hypoxaemia [12, 13]. We noticed no correlation between hepatic functions (synthetic, excretory, transaminases) and PaO2 and/or intrapulmonary shunts. Some authors suggested that ventilation-perfusion disorder (Va/Q) is an important cause of hypoxaemia in
肝肺综合征（HPS）的定义为存在肝脏疾病、低氧血症、吸入室内空气时肺泡 - 动脉氧分压差增加以及肺内血管扩张。肺内血管扩张的病理解剖基础包括扩张的毛细血管前网络、直接动静脉交通以及扩张的胸膜血管，即“胸膜蜘蛛”[2]。近来，肝肺综合征具有了临床重要性。肝病患者动脉氧合恶化提示预后极差，因此有人建议将肝肺综合征列为肝移植的一项新指征[4]。
本研究的目的是探讨肺内分流在呼吸障碍发生发展中的临床及发病机制意义，并确定肝硬化患者肺内分流与临床、生化参数之间的相关性。
在1996 - 1999年进行的一项前瞻性研究中，我们观察了50例肝硬化患者，这些患者在贝尔格莱德塞尔维亚临床中心胃肠病学和肝病科接受检查和治疗。肝脏检查基于病史、体格检查、实验室检查、超声、双功多普勒超声以及组织病理学检查结果。肝衰竭根据Child分级分为3期。在本研究中，我们使用了两组肺功能测试：动脉血气交换分析和通气测试（肺活量测定、流量 - 容积曲线和体容积描记法）。在吸入室内空气时以及吸入高氧混合气15分钟后，分别于仰卧位和坐位进行动脉血气分析。
根据普遍接受的Child分级将患者分为3期：16例患者（32%）处于Child A期，20例患者（40%）处于Child B期，14例（28%）处于Child C期。9例（18%）肝硬化患者被诊断为肝肺综合征。大多数肝肺综合征患者（6例）处于Child C期，另外3例患者处于Child B期。与无分流患者相比，有分流患者的生化参数明显更差。然而，t检验显示无显著差异。7例（14%）患者在仰卧位时存在肺内动静脉分流导致的低氧血症。PaO₂平均值为8.72 kPa（标准差 = 1.02）。9例（18%）患者在坐位时存在动静脉分流导致的低氧血症。平均PaO₂值为7.41 kPa，标准差 = 1.81。所有肺内分流患者均证实存在直立性低氧血症。18例（36%）患者在仰卧位时有无分流的低氧血症，而12例（24%）患者在坐位时有无分流的低氧血症。比较仰卧位时有分流和无分流的患者组，我们发现PaO₂值存在边缘性统计学显著差异（p = 0.057，t检验）。在坐位时，这些组之间的PaO₂值差异具有统计学极显著性（p = 0.001，t检验）。
据推测，约50%有肝移植指征的患者存在某种形式的动脉氧合障碍，其中13 - 47%的患者可能患有肝肺综合征[6, 7]。在我们的研究中，18%的患者被诊断为肝肺综合征。我们将这种高发病率解释为我们的研究纳入了晚期肝硬化患者（Child B和C期）。在以往进行的研究中，肝功能生化参数与肺内分流之间既无相关性，肝衰竭严重程度与低氧血症程度之间也无任何强关联[12, 13]。我们未发现肝功能（合成、排泄、转氨酶）与PaO₂和/或肺内分流之间存在相关性。一些作者认为通气 - 灌注障碍（Va/Q）是低氧血症的一个重要原因。
