Hepatopulmonary syndrome: the anaesthetic considerations

Pulmonary Assessment of the Liver Transplant Recipient

Respiratory symptoms and hypoxemia can complicate chronic liver disease and portal hypertension. Various pulmonary disorders affecting the pleura, lung parenchyma, and pulmonary vasculature are seen in end-stage liver disease, complicating liver transplantation (LT). Approximately 8% of cirrhotic patients in an intensive care unit develop severe pulmonary problems. These disorders affect waiting list mortality and posttransplant outcomes. A thorough history, physical examination, and appropriate laboratory tests help diagnose and assess the severity to risk stratify pulmonary diseases before LT. Hepatopulmonary syndrome (HPS), portopulmonary hypertension (POPH), and hepatic hydrothorax (HH) are respiratory consequences specific to cirrhosis and portal hypertension. HPS is seen in 5-30% of cirrhosis cases and is characterized by impaired oxygenation due to intrapulmonary vascular dilatations and arteriovenous shunts. Severe HPS is an indication of LT. The majority of patients with HPS resolve their hypoxemia after LT. When pulmonary arterial hypertension occurs in patients with portal hypertension, it is called POPH. All other causes of pulmonary arterial hypertension should be ruled out before labeling as POPH. Since severe POPH (mean pulmonary artery pressure [mPAP] >50 mm Hg) is a relative contraindication for LT, it is crucial to screen for POPH before LT. Those with moderate POPH (mPAP >35 mm Hg), who improve with medical therapy, will benefit from LT. A transudative pleural effusion called hepatic hydrothorax (HH) is seen in 5-10% of people with cirrhosis. Refractory cases of HH benefit from LT. In recent years, increasing clinical expertise and advances in the medical field have resulted in better outcomes in patients with moderate to severe pulmonary disorders, who undergo LT.

Cirrhosis and non-hepatic surgery in 2023 - a precision medicine approach

INTRODUCTION

Patients with liver disease and portal hypertension frequently require surgery carrying high morbidity and mortality. Accurately estimating surgical risk remains challenging despite improved medical and surgical management.

AREAS COVERED

This review aims to outline a comprehensive approach to preoperative assessment, appraise methods used to predict surgical risk, and provide an up-to-date overview of outcomes for patients with cirrhosis undergoing non-hepatic surgery.

EXPERT OPINION

Robust preoperative, individually tailored, and precise risk assessment can reduce peri- and postoperative complications in patients with cirrhosis. Established prognostic scores aid stratification, providing an estimation of postoperative mortality, albeit with limitations. VOCAL-Penn Risk Score may provide greater precision than established liver severity scores. Amelioration of portal hypertension in advance of surgery may be considered, with prospective data demonstrating hepatic venous pressure gradient as a promising surrogate marker of postoperative outcomes. Morbidity and mortality vary between types of surgery with further studies required in patients with more advanced liver disease. Patient-specific considerations and practicing precision medicine may allow for improved postoperative outcomes.

Anesthetic Management Using Low Fraction of Inspiratory Oxygen for Living Donor Liver Transplantation in a Patient With Hepatopulmonary Syndrome Complicated by Interstitial Pneumonia: A Case Report

BACKGROUND

Hepatopulmonary syndrome frequently complicates end-stage liver disease. It causes hypoxemia and requires oxygen administration. Additionally, interstitial pneumonia causes hypoxemia; however, it is known to be aggravated by high-concentration oxygen administration.

CASE PRESENTATION

A 71-year-old woman with hepatopulmonary syndrome and interstitial pneumonia underwent living donor liver transplantation, requiring conflicting management in terms of the inspiratory oxygen concentration. We achieved a low intraoperative fraction of inspiratory oxygen by increasing the cardiac output with intravenous catecholamines. As a result, the transplanted liver functioned well postoperatively, and the patient was discharged without exacerbation of the interstitial pneumonia.

CONCLUSION

We suggest that patients with hepatopulmonary syndrome complicated with interstitial pneumonia can undergo successful living donor liver transplantation without the use of high inspiratory oxygen concentration by using catecholamines to maintain a high mixed venous oxygen saturation.

Anesthesia for the Patient with Severe Liver Failure

The incidence of liver failure continues to increase, and it is associated with increased perioperative morbidity and mortality. Liver failure is associated with multiorgan dysfunction, including central nervous, cardiac, respiratory, gastrointestinal, renal, and hematological systems. Preoperative identification, optimization, and tailored anesthetic management are essential for optimum outcomes in patients with liver disease undergoing surgery. The coagulopathy of liver failure is a balanced coagulopathy better assessed by thromboelastography than conventional testing, and it is not directly associated with bleeding risk.

Anesthesia for the Patient with Severe Liver Failure

The incidence of liver failure continues to increase, and it is associated with increased perioperative morbidity and mortality. Liver failure is associated with multiorgan dysfunction, including central nervous, cardiac, respiratory, gastrointestinal, renal, and hematological systems. Preoperative identification, optimization, and tailored anesthetic management are essential for optimum outcomes in patients with liver disease undergoing surgery. The coagulopathy of liver failure is a balanced coagulopathy better assessed by thromboelastography than conventional testing, and it is not directly associated with bleeding risk.

Pulmonary complications after liver transplantation in children: risk factors and impact on early post-operative morbidity

Liver transplantation (LT) is associated with high post-operative morbidity, despite excellent survival rates. With this retrospective study, we report the incidence of early and late pulmonary complications (PC) after LT, identify modifiable risk factors for PC and analyzed the role of PC in post-operative ventilation duration and hospital length of stay. In a series of 79 children (0-16 years) with LT over a 12 years period, early (<3 months post-LT) and/or late (>3 months post-LT) PC occurred in 68 patients (86%). Sixty-four percent (64%) developed early major complications such as pulmonary edema, atelectasis, or pleural effusion. Atelectasis requiring an intervention (P ≤ .02), pulmonary edema (P ≤ .02), or elevated PELD/MELD scores (P = .05) were associated with an increase in total ventilation duration and length of stay in the ICU. Risk factors for early PC included preoperative hypoxemia (P = .005), low serum albumin at LT admission (P = .003), or early rejection (P = .002). About 20% of patients experienced late PC of which 81% were infections. Risk factor assessment prior to LT may ultimately help reduce early PC thereby possibly minimizing post-operative morbidity and ICU length of stay.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Implications for Liver Transplantation

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) represent serious pulmonary complications of advanced liver diseases. Orthotopic liver transplantation (OLT) is capable of completely resolving the underlying abnormalities associated with HPS. On the other hand, post-OLT response in patients with PoPH is less predictable, although heavily influenced by pre-OLT mean pulmonary arterial pressure. It remains the case that the opportunity to reverse 2 potentially fatal organ dysfunctions in the liver and the lung make HPS and PoPH more than worthy for further clinical investigations.

Perioperative Care of the Liver Transplant Patient

With the evolution of surgical and anesthetic techniques, liver transplantation has become "routine," allowing for modifications of practice to decrease perioperative complications and costs. There is debate over the necessity for intensive care unit admission for patients with satisfactory preoperative status and a smooth intraoperative course. Postoperative care is made easier when the liver graft performs optimally. Assessment of graft function, vigilance for complications after the major surgical insult, and optimization of multiple systems affected by liver disease are essential aspects of postoperative care. The intensivist plays a vital role in an integrated multidisciplinary transplant team.

International Liver Transplant Society Practice Guidelines: Diagnosis and Management of Hepatopulmonary Syndrome and Portopulmonary Hypertension

Two distinct pulmonary vascular disorders, hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) may occur as a consequence of hepatic parenchymal or vascular abnormalities. HPS and POPH have major clinical implications for liver transplantation. A European Respiratory Society Task Force on Pulmonary-Hepatic Disorders convened in 2002 to standardize the diagnosis and guide management of these disorders. These International Liver Transplant Society diagnostic and management guidelines are based on that task force consensus and should continue to evolve as clinical experience dictates. Based on a review of over 1000 published HPS and POPH articles identified via a MEDLINE search (1985-2015), clinical guidelines were based on, selected single care reports, small series, registries, databases, and expert opinion. The paucity of randomized, controlled trials in either of these disorders was noted. Guidelines are presented in 5 parts; I. Definitions/Diagnostic criteria; II. Hepatopulmonary syndrome; III. Portopulmonary hypertension; IV. Implications for liver transplantation; and V. Suggestions for future clinical research.

Anesthesia for Patients with Concomitant Hepatic and Pulmonary Dysfunction

Hepatic function and pulmonary function are interrelated with failure of one organ system affecting the other. With improved therapies, patients with concomitant hepatic and pulmonary failure increasingly enjoy a good quality of life and life expectancy. Therefore, the prevalence of such patients is increasing with more presenting for both emergent and elective surgical procedures. Hypoxemia requires a thorough evaluation in patients with end-stage liver disease. The most common etiologies respond to appropriate therapy. Portopulmonary hypertension and hepatopulmonary syndrome are associated with increased perioperative morbidity and mortality. It is incumbent on the anesthesiologist to understand the physiology of liver failure and its early effect on pulmonary function to ensure a successful outcome.

Mechanical characteristics of the pulmonary artery in beagle dogs with hepatopulmonary syndrome and portopulmonary hypertension

The continuous changes in pulmonary hemodynamic properties in hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) have not been fully characterized in large animal models of HPS and PoPH. Beagle dog models of HPS and PoPH were induced by chronic common bile duct ligation and Sephadex microspheres, respectively. The model was validated by catheter examination and pathological analyses, and the hemodynamic characteristics of the models were observed. The results revealed that the cross-sectional area of the blood vessel was significantly increased in HPS models, but it was significantly decreased in the PoPH models. Furthermore, the resistance of pulmonary circulation was elevated in models of HPS, but it was decreased in models of PoPH. The present findings renew the traditional view that pulmonary hypertension is due to the enhanced peripheral resistance.

Kidney injury in cirrhosis: pathophysiological and therapeutic aspects of hepatorenal syndromes

Acute kidney injury (AKI) is frequent in patients with cirrhosis. AKI and hyponatraemia are major determinants of the poor prognosis in advanced cirrhosis. The hepatorenal syndrome (HRS) denotes a functional and potential reversible impairment of renal function. Type 1 HRS, a special type of AKI, is a rapidly progressive AKI, whereas the renal function in type 2 HRS decreases more slowly. HRS is precipitated by factors such as sepsis that aggravate the effective hypovolaemia in decompensated cirrhosis, by lowering arterial pressure and cardiac output and enhanced sympathetic nervous activity. Therefore, attempts to prevent and treat HRS should seek to improve liver function and to ameliorate arterial hypotension, central hypovolaemia and cardiac output, and to reduce renal vasoconstriction. Ample treatment of HRS is important to prevent further progression and death, but as medical treatment only modestly improves long-term survival, these patients should always be considered for liver transplantation. Hyponatraemia, defined as serum sodium <130 mmol/L, is common in patients with decompensated cirrhosis. From a pathophysiological point of view, hyponatraemia is related to an impairment of renal solute-free water excretion most likely caused by an increased vasopressin secretion. Patients with cirrhosis mainly develop hypervolaemic hyponatraemia. Current evidence does not support routine use of vaptans in the management of hyponatraemia in cirrhosis.

Portopulmonary hypertension and hepatopulmonary syndrome

Portopulmonary hypertension (POPH) and hepatopulmonary syndrome (HPS) are two frequent complications of liver disease, with prevalence among liver transplant candidates of 6% and 10%, respectively. Both conditions result from a lack of hepatic clearance of vasoactive substances produced in the splanchnic territory. Subsequently, these substances cause mainly pulmonary vascular remodeling and some degree of vasoconstriction in POPH with resulting elevated pulmonary pressure and right ventricular dysfunction. In HPS the vasoactive mediators cause intrapulmonary shunts with hypoxemia. Medical treatment is disappointing overall. Whereas liver transplantation (LT) results in the disappearance of HPS within six to twelve months, its effect on POPH is highly unpredictable. Modern strategies in managing HPS and POPH rely on a thorough screening and grading of the disease’s severity, in order to tailor the appropriate therapy and select only the patients who will benefit from LT. The anesthesiologist plays a central role in managing these high-risk patients. Indeed, the important hemodynamic and respiratory modifications of the perioperative period must be avoided through continuation of the preoperatively initiated drugs, appropriate intraoperative monitoring and proper hemodynamic and respiratory therapies.