[Gasometric alterations in hospitalized cirrhotic patients]

BACKGROUND AND OBJECTIVES

Gas exchange alterations have been described in cirrhotic patients; but by the moment, a few prospective studies have focused in them. The aim of this study was to describe the frequency and severity of gasometric alterations in hospitalized cirrhotic patients, a their correlation with hepatocellular disfunction.

PATIENTS AND METHODS

50 consecutive cirrhotic patients (41 males) admitted for liver decompensation (ascites, liver encephalopathy, alcoholic hepatitis and upper gastrointestinal bleeding) without acute or chronic cardiopulmonary disfunction were included in the study. Patients were classified according with Child-Pugh score (A, n = 13; B, n = 21; C, n = 16). Severe alcoholic hepatitis (SAH) was confirmed in 7 patients. Arterial gasometry was performed in all patients before discharge. Contrast echocardiography was performed in any case of suspicion of hepatopulmonary syndrome (HPS).

RESULTS

Light hypoxemia was observed (80.9 mmHg), without differences with Child-Pugh. Hypocapnia was significantly more evident in Child C than in A and B (31.2 +/- 3.1 vs. 38.1 +/- 4.3 y 36.3 +/- 5 mmHg; p < 0,05), respectively. Cirrhotic patients with SAH showed a significantly higher hypocapnia by comparison with others (31.2 +/- 3.1 vs. a 36.3+/-5 mmHg; p < 0.05). In multivariate analysis, independent prognostic variables for hypocapnica were plasmatic levels of protrombin time, albumin and sodium. HPS was confirmed in 8 patients (16%).

CONCLUSIONS

The most prevalent gas exchange abnormality in cirrhosis was the alteration of alveolar-arterial oxygen tension gradient, directly correlated with hepatocellur disfunction. Hypocapnia could be a compensatory mechanism or the result of the activation of central respiratory centres by non-depurated substances by the liver.

Portopulmonary hypertension in a patient of autoimmune hepatitis

A 35-year-old women presented with breathlessness and features suggestive of pulmonary hypertension. Further investigations revealed that she had autoimmune hepatitis and both portal and pulmonary hypertension. Pertinent literature is reviewed.

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

RACIONAL: A síndrome hepatopulmonar é caracterizada por tríade clínica que consiste em: 1) doença hepática e/ou hipertensão portal, 2) dilatações vasculares intra-pulmonares, e 3) anormalidades da oxigenação arterial (pressão parcial de oxigênio <70 mm Hg ou gradiente alvéolo-arterial de oxigênio >20 mm Hg). Sua freqüência varia de acordo com os métodos diagnósticos utilizados. OBJETIVOS: Fazer revisão da literatura sobre patogenia, diagnóstico e tratamento da síndrome hepatopulmonar. MÉTODOS: Levantamento no MEDLINE das publicações nacionais e internacionais mais relevantes sobre a síndrome hepatopulmonar. RESULTADOS: A prevalência da síndrome hepatopulmonar varia de 4% a 17,5%, a depender dos critérios diagnósticos utilizados. A doença hepática associada mais comum é a cirrose. O gradiente alvéolo-arterial de oxigênio parece ser o melhor parâmetro para avaliação das anormalidades da oxigenação arterial. Em relação à detecção das dilatações vasculares intra-pulmonares, a ecocardiografia com contraste é o método de escolha, pois é de fácil realização e pode diferenciar as comunicações intra-pulmonares das intra-cardíacas. No tratamento da síndrome hepatopulmonar, poucos relatos bem sucedidos puderam ser reproduzidos e confirmados utilizando terapia farmacológica e/ou radiologia intervencionista. Atualmente, o transplante de fígado é considerado a principal opção terapêutica desses pacientes, com resultados animadores. CONCLUSÕES: A síndrome hepatopulmonar é uma enfermidade freqüente. Exames gasométricos são necessários para o seu diagnóstico. O transplante de fígado é o tratamento de escolha para os portadores da síndrome.

Hepatopulmonary syndrome

The hepatopulmonary syndrom occurs when pulmonary microvacular dilatation causes hypoxemia in cirrhosis. It is found in between 15-20% of patients with chronic liver diseases and should be considered in the differential diagnosis of dyspnea or abnormal arterial oxygenation in this group. The presence of HPS appears to significantly increase mortality in affected patients with cirrhosis. The mediators of intrapulmonary vasodilatation and HPS are not fully characterized although pulmonary nitric oxide overproduction appears to be a key event in human and experimental models. Contrast echocardiography is the best screening test for pulmonary vasodilatation. Currently there are no effective medical therapies for HPS, although liver transplantation results in reversal of HPS in most cases. However, mortality is higher in patients with HPS undergoing transplantation relative to those without HPS.

Role of the chest radiograph in the preoperative assessment of the pulmonary function in patients with cirrhosis candidates to liver transplant

PURPOSE

To appraise the role of chest radiography (CXR) in the clinical assessment of pulmonary complications occurring as a result of liver disease of any cause, a standardised reading of CXR was compared both with the results of lung function studies and with the severity of liver disease in 60 consecutive patients with cirrhosis candidates to liver transplant.

MATERIALS AND METHODS

CXR were scored for signs of cardiomegaly, enlargement of central and or peripheral vessels, hyperkinetic circulatory and/or intravascular volume states, abnormally increased interstitial lung markings, and pleural effusion by three independent observers.

RESULTS

The CXR score of this complete vascular-interstitial deficiency showed a high interobserver reproducibility and was significantly increased in those patients with a more decompensated liver cirrhosis. Moreover, a larger number of CXR signs of vascular and interstitial deficiency was present in those patients who had a more severe cirrhosis (Child-Pugh class 3). Functional indices of pulmonary gas exchange and diffusing capacity were worse in patients with end-stage liver cirrhosis, and for some indices the correlation was statistically significant. The comparison between lung function and CXR score showed that on average lung function impairment was significantly less severe in patients with lower CXR scores.

CONCLUSIONS

In conclusion, the information derived from a standardised reading of CXR is valuable in the clinical assessment of the pulmonary damage induced by liver cirrhosis as it allows discrimination of classes of severity of liver disease and of lung function impairment. When integrated with physiologic measurements and, if necessary, with high resolution tomographic studies, chest radiography helps to discriminate patients with advanced liver cirrhosis and progressing towards a hepatopulmonary syndrome, who need a proper therapeutic management.

[Imaging findings of pulmonary vascular disorders in portal hypertension]

PURPOSE

The purpose of this study was to demonstrate and compare the imaging findings of hepatopulmonary syndrome and portopulmonary hypertension.

MATERIALS AND METHODS

We retrospectively reviewed the imaging findings of five patients with hepatopulmonary syndrome and four patients with portopulmonary hypertension. We evaluated chest radiographs, chest and abdominal computed tomography (CT) scans, 99mTc-macroaggregated albumin (MAA) lung perfusion scans, and pulmonary angiograms.

RESULTS

In patients with hepatopulmonary syndrome, the presence of peripheral pulmonary vascular dilatation was detected by chest radiograph, chest CT scan, and pulmonary angiogram, especially the basilar segment. 99mTc-MAA lung perfusion scan showed extrapulmonary tracer distribution (brain, thyroid, and kidney), which revealed pulmonary R-L shunting. In patients with portopulmonary hypertension, chest radiographs and chest CT scans showed the classic findings of primary pulmonary hypertension. In patients with both disorders, extrahepatic features of portal hypertension including ascites, splenomegaly, and portosystemic collateral vessels were seen on abdominal CT.

CONCLUSION

In conclusion, chest radiographs and CT in hepatopulmonary syndrome usually showed peripheral pulmonary vascular dilatation, whereas those in portopulmonary hypertension showed central pulmonary artery dilatation. The extrahepatic features of portal hypertension might be helpful for the diagnosis of both disorders.

[Living-related liver transplantation in a patient with hepatopulmonary syndrome]

We experienced the perioperative management of the living related liver transplantation (LRLT) in a patient with hepatopulmonary syndrome (HPS). HPS is seen in 15% of patients of the endstage liver failure, and it accompanies the various types of hypoxia. The diagnostic standards of HPS are chronic liver disease usually complicated by portal hypertension with or without cirrhosis, arterial hypoxemia (PaO2 < 70 mmHg or A-aDO2 gradient > 20 mmHg), and intrapulmonary vascular dilation. The present case conformed to the diagnostic standard. But this case was of a mild type of HPS, because PaO2 was elevated after O2 inhalation and extrapulmonary uptake of 99mTcMAA after lung perfusion was lower than 40%. During perioperative period of LRLT, there were no complications such as hypoxia, acute rejection, bleeding and infection. Therefore HPS would be improved after LRLT. In the management of perioperative period it is important to be aware of hypoxia and to evaluate preoperatively the condition of the patient properly.

Hepatopulmonary syndrome in a patient with primary biliary cirrhosis

A 54-year-old Japanese woman with primary biliary cirrhosis (PBC) was admitted to our hospital due to hepatic coma and refractory pleural effusion. The physical examination revealed clubbed fingers and collateral veins. The patient had an increased alveolar-arterial oxygen gas tension difference. The levels of anti-mitochondrial antibody (AMA) and AMA M2 was 80 times normal. A technetium 99m-labeled macro-aggregated human albumin scintigram showed uptake in the spleen and the kidneys. A diagnosis of hepatopulmonary syndrome (HPS) was made. HPS may be overlooked because of the lack of symptoms. We conclude that closer attention should be paid to the occurrence of HPS.

Hepatopulmonary syndrome: role of nitric oxide and clinical aspects

Hepatopulmonary syndrome is defined by oxygenation impairment due to abnormal intrapulmonary vascular dilatations in patients with liver disease. The implication of enhanced pulmonary production of nitric oxide in the pathogenesis of intrapulmonary vascular dilatations has been demonstrated both in murine models and in human hepatopulmonary syndrome. The diagnosis of hepatopulmonary syndrome in chronic liver disease is of paramount importance, considering the fact that severe hypoxemia related to hepatopulmonary syndrome may occur in patients with well compensated liver disease and that survival is reduced in patients with hepatopulmonary syndrome relative to non hepatopulmonary syndrome patients. Priority for liver transplantation, which is presently the only cure, has been recently increased in patients with advanced hepatopulmonary syndrome.

Hepatopulmonary syndrome after living donor liver transplantation and deceased donor liver transplantation: a single-center experience

Hepatopulmonary syndrome (HPS) is a progressive, debilitating complication of end-stage liver disease. In contrast to the well-established reversal of HPS after deceased donor liver transplantation (DDLT), little has been written about the natural course of HPS after the newer procedure of living donor liver transplantation (LDLT). We describe HPS in a small series of 4 liver transplant recipients (2 DDLT; 2 LDLT) at a single center. Before transplantation, these 4 patients had a mean shunt fraction of 23.6 +/- 14.3% and a mean PaO2 of 58.5 +/- 11.3 mm Hg. All 4 patients used supplemental oxygen before transplantation. Sixteen weeks after transplantation, all 4 patients had normalized or improved shunt fraction and PaO2. These patients regained normal pulmonary function within a few months, despite the period of hepatic regeneration after LDLT. In conclusion, both DDLT and LDLT are associated with rapid and dramatic reversal of HPS.

Hepatopulmonary syndrome: a concern for the anesthetist? Pre-operative evaluation of hypoxemic patients with liver disease

Liver cirrhosis and other chronic hepatic diseases are followed in a subset of affected patients by gas exchange abnormalities resulting from a syndrome called hepatopulmonary syndrome (HPS). The structural basis of this clinical entity is an alteration of pulmonary vasculature resulting in abnormal vasodilatation and mismatching of ventilation and perfusion of the lung. Dilatation of the capillary bed near the gas exchange area is the most important factor implicated; it precludes O2 molecules diffusing to the centrum of the dilated vessels to oxygenate venous blood. Contrast (microbubbles) echocardiography and lung perfusion scan are, respectively, the screening tests with the highest sensitivity and specificity for HPS diagnosis. Because of the high morbidity and mortality of HPS, clinicians have been trying to understand the pathophysiology of pulmonary vasodilatation in the hope that the process can be reversed pharmacologically or surgically. An imbalance between production and clearance of vasoactive circulating substances has been implicated in the pathogenesis of HPS with glucagon and nitric oxide among the principal responsible factors. To date various molecules have been implicated for therapy but without definitive positive results. Liver transplantation remains the only real therapy for HPS, and resolution of gas exchange defects outlines the possible functional reversible nature of vascular abnormalities of this syndrome. The need to perform surgery under general anesthesia for hepatic and extrahepatic procedures in patients with HPS is followed by an increased peri-operative risk. The authors emphasize the role of pre-operative clinical evaluation for proper patient management during the peri-operative period.

The significance of hepatopulmonary syndrome in liver transplantation

The objective of the study is to determine the diagnostic role of pulmonary functional tests and perfusion pulmonary scintigraphy for quantifying the oxygenation and vascular abnormality in patients with liver cirrhosis. The prospective study included 70 patients with liver cirrhosis. Arterial blood gases analysis were performed in both supine and sitting positions while inhaling room air, and 15 minutes after exposure of hyperoxic mixture. Perfusion pulmonary scintigraphy using albumin macroagregate labelled with radioactive technetium (99mTc-MAA) was performed for the visualisation of intrapulmonary vascular dilatation. The diagnosis of hepatopulmonary syndrome was made in 10 (14.3%) patients. The patients with hepatopulmonary syndrome had severe hypoxemia (Pa,O2 7.41 +/- 1.81 kPa), and poor response to 100% oxygen inhalation (Pa,O2 21.07 +/- 14.41 kPa) and higher alveolo-arterial gradient (5.73 +/- 2.65 kPa). Radioisotope marker 99mTc-MAA skipped intrapulmonary circulation in all patients with HPS and in no one without pulmonary vascular dilatations. The combined approach of 100% inspired oxygen and perfusion pulmonary scintigraphy may identify early oxygenation disorders and alter the priority for liver transplantation, especially in view of potential syndrome resolution.

Frequency, clinical characteristics, and respiratory parameters of hepatopulmonary syndrome

OBJECTIVES

To determine the frequency and the clinical characteristics of hepatopulmonary syndrome (HPS) in cirrhotic candidates for orthotopic liver transplantation and to identify the major respiratory parameters predictive of the presence of changes in arterial oxygenation.

PATIENTS AND METHODS

Patients underwent transthoracic contrast-enhanced echocardiography, pulmonary scintigraphy, pulmonary function test with diffusing capacity of lung for carbon monoxide (DLCO), and measurement of arterial blood gases.

RESULTS

Fifty-six patients were studied. Twenty-five patients (45%) presented with intrapulmonary vascular dilatations, but only 9 (16%) fulfilled the criteria for HPS. The clinical or demographic characteristics considered did not differ in the patients with and without HPS. The DLCO value was significantly lower in patients with HPS (P=.01). However, 32 (80%) of 40 patients with low DLCO values did not fulfill the criteria for HPS. An alveolar arterial oxygen gradient (AaPO2) of more than 20 mm Hg showed a higher diagnostic accuracy (91%) in the assessment of HPS than did the DLCO of less than 80% predicted (41%) and the AaPO2 of more than 15 mm Hg (71%).

CONCLUSIONS

The AaPO2 proved to be a more reliable index than PaO2 and DLCO for the determination of changes in arterial oxygenation in HPS. The DLCO does not seem to be a good marker for HPS screening. Intrapulmonary vascular dilatations were frequent, even in patients who did not fulfill the criteria for HPS.