Incidence and clinical outcomes of ventilator-associated pneumonia in liver transplant and non-liver transplant surgical patients. Transplant Proc. 2008;40:1986-1988. [PMID: 18675108 DOI: 10.1016/j.transproceed.2008.05.022]

Ventilator-Associated Pneumonia in Immunosuppressed Patients

Immunocompromised patients-including patients with cancer, hematological malignancies, solid organ transplants and individuals receiving immunosuppressive therapies for autoimmune diseases-account for an increasing proportion of critically-ill patients. While their prognosis has improved markedly in the last decades, they remain at increased risk of healthcare- and intensive care unit (ICU)-acquired infections. The most frequent of these are ventilator-associated lower respiratory tract infections (VA-LTRI), which include ventilator-associated pneumonia (VAP) and tracheobronchitis (VAT). Recent studies have shed light on some of the specific features of VAP and VAT in immunocompromised patients, which is the subject of this narrative review. Contrary to previous belief, the incidence of VAP and VAT might actually be lower in immunocompromised than non-immunocompromised patients. Further, the relationship between immunosuppression and the incidence of VAP and VAT related to multidrug-resistant (MDR) bacteria has also been challenged recently. Etiological diagnosis is essential to select the most appropriate treatment, and the role of invasive sampling, specifically bronchoscopy with bronchoalveolar lavage, as well as new molecular syndromic diagnostic tools will be discussed. While bacteria-especially gram negative bacteria-are the most commonly isolated pathogens in VAP and VAT, several opportunistic pathogens are a special concern among immunocompromised patients, and must be included in the diagnostic workup. Finally, the impact of immunosuppression on VAP and VAT outcomes will be examined in view of recent papers using improved statistical methodologies and treatment options-more specifically empirical antibiotic regimens-will be discussed in light of recent findings on the epidemiology of MDR bacteria in this population.

Posttransplant Pneumonia Among Solid Organ Transplant Recipients Followed in Intensive Care Unit

OBJECTIVES

Pneumonia is a significant cause of morbidity and mortality in solid-organ transplant recipients. We studied the demographic characteristics, respiratory management, and outcomes of solid-organ transplant recipients with pneumonia in an intensive care unit.

MATERIALS AND METHODS

There have been 2857 kidney, 687 liver, and 142 heart transplants performed between October 16, 1985, and February 28, 2021, at our center. We retrospectively analyzed records for 51 of 193 recipients with pneumonia during the posttransplant period between January 1, 2016, and December 31, 2018.

RESULTS

Fifty-one of 193 recipients were followed in the intensive care unit. Mean age was 45.4 ± 16.6 years among 42 male (82.4%) and 9 female (17.6%) recipients. Twenty-six patients (51%) underwent kidney transplant, 14 (27.5%) liver transplant, 7 (13.7%) heart transplant, and 4 (7.8%) combined kidney and liver transplant. Most pneumonia episodes occurred 6 months after transplant (70.6%) with acute hypoxemic respiratory failure. Mean Acute Physiology and Chronic Health Evaluation System II score was 18.9 ± 7.7, and the Sequential Organ Failure Assessment score was 8.5 ± 3.9 at intensive care unit admission. Whereas 66.7% of pneumonia cases were nosocomial acquired, 33.3% were community acquired. The intensive care unit and 28-day mortality rates were 39.2% and 64.7%, respectively.

CONCLUSIONS

Solid-organ transplant recipients with pneumonia have been associated with poor prognosis. Our cohort followed in the intensive care unit comprised mostly patients with nosocomial pneumonia with acute hypoxemic respiratory failure, hospitalized 6 months after transplant with high Acute Physiology and Chronic Health Evaluation System II scores predictive of mortality. In this high-risk patient group, careful follow-up, early discovery of warning signs, and rapid treatment initiation could improve the outcomes in the intensive care unit.

Is hospital-acquired pneumonia different in transplant recipients?

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are serious complications in transplant patients. The aim of this review is to summarize the evidence regarding nosocomial pneumonia in transplant recipients, including HAP in non-ventilated patients and VAP, and to identify future directions for improvement.A comprehensive literature search in the PubMed/MEDLINE database was performed. Articles written in English and published between 1990 and November 2018 were included. HAP/VAP in transplant patients usually occurs early post-transplant, particularly during neutropenia in haematopoietic stem cell transplant recipients. Bacteria are the leading cause of nosocomial pneumonia for both immunocompetent and transplant recipients, being Gram negative organisms, and especially Pseudomonas aeruginosa, highly prevalent. Multidrug-resistant bacteria are of special concern. Pneumonia in the transplant setting may be caused by opportunistic pathogens, and the differential diagnosis needs to be extended to other non-infectious complications. The most relevant opportunistic pathogens are Aspergillus fumigatus, Pneumocystis jirovecii and cytomegalovirus. Nevertheless, they are an exceptional cause of nosocomial pneumonia, and usually occur in severely immunosuppressed patients not receiving antimicrobial prophylaxis. Performing bronchoalveolar lavage may improve the rate of aetiological diagnosis, leading to a change in therapeutic management and improved outcomes. The optimal length of antibiotic therapy for bacterial HAP/VAP has not been well defined, but it should perhaps be longer than in the general population. Mortality associated with HAP/VAP is high. HAP/VAP in transplant patients is frequent and is associated with increased mortality. There is room for improvement in gaining knowledge about the management of HAP/VAP in this population.

Ventilator associated pneumonia following liver transplantation: Etiology, risk factors and outcome

AIM: To determine the incidence, etiology, risk factors and outcome of ventilator-associated pneumonia (VAP) in patients undergoing orthotopic liver transplantation (OLT).

METHODS: This retrospective study considered 242 patients undergoing deceased donor OLT. VAP was diagnosed according to clinical and microbiological criteria.

RESULTS: VAP occurred in 18 (7.4%) patients, with an incidence of 10 per 1000 d of mechanical ventilation (MV). Isolated bacterial etiologic agents were mainly Enterobacteriaceae (79%). Univariate logistic analysis showed that model for end-stage liver disease (MELD) score, pre-operative hospitalization, treatment with terlipressin, Child-Turcotte-Pugh score, days of MV and red cell transfusion were risk factors for VAP. Multivariate analysis, considering significant risk factors in univariate analysis, demonstrated that pneumonia was strongly associated with terlipressin usage, pre-operative hospitalization, days of MV and red cell transfusion. Mortality rate was 22% in the VAP group vs 4% in the group without VAP.

CONCLUSION: Our data suggest that VAP is an important cause of nosocomial infection during postoperative period in OLT patients. MELD score was a significant risk factor in univariate analysis. Multiple transfusions, treatment with terlipressin, preoperative hospitalization rather than called to the hospital while at home and days of MV constitute important risk factors for VAP development.

A meta-analysis of complications following deceased donor liver transplant

BACKGROUND

Liver transplantation is a complex surgery associated with high rates of postoperative complications. While national outcomes data are available, national rates of most complications are unknown.

DATA SOURCES

A systematic review of the literature reporting rates of postoperative complications between 2002 and 2012 was performed. A cohort of 29,227 deceased donor liver transplant recipients from 74 studies was used to calculate pooled incidences for 17 major postoperative complications.

CONCLUSIONS

This is the first comprehensive review of postoperative complications after liver transplantation and can serve as a guide for transplant and nontransplant clinicians. Efforts to collect national data on complications, such as through the National Surgical Quality Improvement Program, would improve the ability to provide patients with informed consent, serve as a tool for individual center performance monitoring, and provide a central source against which to measure interventions aimed at improving patient care.

Defining and characterizing severe hypoxemia after liver transplantation in hepatopulmonary syndrome

Hepatopulmonary syndrome is defined as a triad of liver disease, intrapulmonary vascular dilatations, and abnormal gas exchange, and it carries a poor prognosis. Liver transplantation is the only known cure for this syndrome. Severe hypoxemia in the early postoperative period has been reported to be a major complication and often leads to death in this population, but it has been poorly characterized. We sought to propose an objective definition for this complication and to describe its risk factors, incidence, and outcomes. We performed a systematic literature search and reviewed our single-center experience to characterize this complication. On the basis of the most commonly applied definition in 27 identified studies, we objectively defined severe postoperative hypoxemia as hypoxemia requiring a 100% fraction of inhaled oxygen to maintain a saturation ≥ 85% and out of proportion to any concurrent lung process. Nineteen of the 27 reports (70%) fulfilled this definition, as did 4 of the 21 patients (19%) at our center. We determined the prevalence and mortality of this complication from reports including 10 or more consecutive patients and providing sufficient postoperative details to determine whether this complication had occurred. In these reports, the prevalence of this complication was 12% (25/209). For the 11 cases with reported outcomes, the posttransplant mortality rate was 45% (5/11). There was a trend toward an increased risk of developing this complication in patients with very severe preoperative hypoxemia, defined as a partial pressure of arterial oxygen ≤ 50 mm Hg (8/41 with very severe hypoxemia versus 3/49 without severe hypoxemia, P = 0.053), and there was a significantly increased risk for patients with anatomic shunting ≥ 20% (7/25 with anatomic shunting ≥ 20% versus 1/25 without anatomic shunting ≥ 20%, P = 0.049). In conclusion, increased preoperative vigilance for this common complication is required among high-risk patients, and further research is required to identify the best management strategies.

Pulmonary complications after elective liver transplantation-incidence, risk factors, and outcome

After liver transplantation (LT), postoperative pulmonary complications (PPC) occur in approximately 35% to 50% of the recipients. Among these PPC, pneumonia is the most frequently encountered. Pulmonary dysfunction has also been widely reported among patients awaiting LT. The links between this dysfunction and PPC have not been clearly established. In this present cohort study, we evaluated the incidence and profile of post-LT pneumonia and identified potential preoperative risk factors.

METHODS

The postoperative clinical course of 212 liver transplant recipients between January 2008 and April 2010 was analyzed. These patients were treated in a single intensive care unit and received standardized postoperative care.

RESULTS

During the postoperative period, 47 (22%) patients developed pneumonia, of whom 20 (43%) developed respiratory failure requiring mechanical ventilation. Univariate analysis showed that several preoperative factors (age of recipient, model for end-stage liver disease score, indication for LT, platelet count, and restrictive lung pattern revealed by preoperative pulmonary function tests) and the transfusion (blood units and fresh frozen plasma units) during the operative period were associated with pneumonia. Using multivariate analysis by logistic regression, only a restrictive lung pattern (odds ratio=3.14; 95% confidence interval, 1.51-6.51; P=0.002) and the international normalized ratio measured prior LT (OR=4.95; 95% confidence interval, 1.86-8.59; P=0.0004) were independent predictors of pneumonia after LT.

CONCLUSION

Pneumonia is common among patients undergoing LT and is a major cause of morbidity. A restrictive pattern on preoperative pulmonary testing and a higher international normalized ratio measured prior LT were associated with more risk of postoperative pneumonia.

Liver transplantation in patients with liver cirrhosis and active pneumonia: an observational study

Patients with chronic liver disease are at high risk for severe infection because of increased bacterial translocation and immune suppression associated with liver dysfunction. Patients presenting with severe pneumonia and acute decompensation of cirrhosis are generally not considered for liver transplantation because it is unknown if these patients can recover from infection while under immunosuppression. We performed an observational study where patients with cirrhosis of the liver remained on the waiting list, although suffering from active pneumonia. Nine patients were included, but only six patients improved under goal-directed therapy and subsequently underwent liver transplantation. All six patients recovered quickly from infection; five patients recovered without sequelae and one patient died because of late complications. We propose that in patients with chronic liver disease and active pneumonia transplantation is a treatment option that should not hastily be abandoned.

Early-onset pneumonia after liver transplantation: microbiological findings and therapeutic consequences

Early-onset hospital-acquired pneumonia (E-HAP) is one of the leading causes of sepsis and mortality after liver transplantation (LT). The appropriate antimicrobial therapy is crucially important for surviving sepsis in this context. The aim of this study was to analyze microbiological findings, associated factors, and optimal antibiotic regimens for E-HAP after LT. Patients demonstrating E-HAP in a single-center cohort of 148 LT recipients were prospectively detected. The diagnosis of pneumonia relied on a combination of supportive clinical findings and a positive culture of a lower respiratory tract sample. E-HAP was considered present if pneumonia occurred within 6 days of intensive care unit (ICU) admission after LT. Twenty-three patients (15.5%) developed E-HAP, which were caused by 36 pathogens (61.1% were gram-negative bacilli, and 33.3% were classified as hospital-acquired). For patients who developed E-HAP, the duration of mechanical ventilation and the ICU stay were significantly longer. Despite a trend toward higher mortality at any time in the E-HAP group, there was no significant difference in mortality between patients with E-HAP and patients without E-HAP. Lactatemia, vasopressor requirements, Simplified Acute Physiology Score II (SAPS II) score on ICU admission, and mechanical ventilation lasting more than 48 hours after LT were associated with E-HAP. Combinations of broad-spectrum β-lactams and aminoglycosides were active against more than 91% of the encountered pathogens. However, antibiotic de-escalation was possible in more than one-third of cases after identification of the pathogens. In conclusion, E-HAP after LT is a severe condition that appears to be influenced by physiological derangements induced by the surgery, such as lactatemia, vasopressor requirements, and mechanical ventilation requirements, as well as the postoperative SAPS II score. At the time of treatment initiation, an antimicrobial regimen usually proposed for late-onset pneumonia should be followed.