Increased utilization of the hybrid procedure is not associated with improved early survival for newborns with hypoplastic left heart syndrome: a single-centre experience

OBJECTIVES

The primary objectives were to examine utilization of the Hybrid versus the Norwood procedure for patients with hypoplastic left heart syndrome or variants and the impact on hospital mortality. The Hybrid procedure was 1st used at our institution in 2004.

METHODS

Review of all subjects undergoing the Norwood or Hybrid procedure between 1 January 1984 and 31 December 2022. The study period was divided into 8 eras: era 1, 1984-1988; era 2, 1989-1993; era 3, 1994-1998; era 4, 1999-2003; era 5, 2004-2008; era 6, 2009-2014; era 7, 2015-2018 and era 8, 2019-2022. The primary outcome was in-hospital mortality. Mortality rates were computed using standard binomial proportions with 95% confidence intervals. Rates across eras were compared using an ordered logistic regression model with and adjusted using the Tukey-Kramer post-hoc procedure for multiple comparisons. In the risk-modelling phase, logistic regression models were specified and tested.

RESULTS

The Norwood procedure was performed in 1899 subjects, and the Hybrid procedure in 82 subjects. Use of the Hybrid procedure increased in each subsequent era, reaching 30% of subjects in era 8. After adjustment for multiple risk factors, use of the Hybrid procedure was significantly and positively associated with hospital mortality.

CONCLUSIONS

Despite the increasing use of the Hybrid procedure, overall mortality for the entire cohort has plateaued. After adjustment for risk factors, use of the Hybrid procedure was significantly and positively associated with mortality compared to the Norwood procedure.

Lung transplant outcomes after acute respiratory distress syndrome requiring extracorporeal life support: Lessons from the COVID-19 pandemic

OBJECTIVE

Lung transplant for acute respiratory distress syndrome in patients supported with extracorporeal membrane oxygenation was rare before 2020, but was rapidly adopted to rescue patients with COVID-19 with lung failure. This study aims to compare the outcomes of patients who underwent lung transplant for COVID-associated acute respiratory distress syndrome and non-COVID acute respiratory distress syndrome, and to assess the impact of type and duration of extracorporeal membrane oxygenation support on survival.

METHODS

Using the United Network for Organ Sharing database, we identified 311 patients with acute respiratory distress syndrome who underwent lung transplant from 2007 to 2022 and performed a retrospective analysis of the patients who required extracorporeal membrane oxygenation preoperatively, stratified by COVID-associated acute respiratory distress syndrome and non-COVID acute respiratory distress syndrome listing diagnoses. The primary outcome was 1-year survival. Secondary outcomes included the effect of type and duration of extracorporeal membrane oxygenation on survival.

RESULTS

During the study period, 236 patients with acute respiratory distress syndrome and preoperative extracorporeal membrane oxygenation underwent lung transplant; 181 patients had a listing diagnosis of COVID-associated acute respiratory distress syndrome (77%), and 55 patients had a listing diagnosis of non-COVID acute respiratory distress syndrome (23%). Patients with COVID-associated acute respiratory distress syndrome were older, were more likely to be female, had higher body mass index, and spent longer on the waitlist (all P < .02) than patients with non-COVID acute respiratory distress syndrome. The 2 groups had similar 1-year survival (85.8% vs 81.1%, P = .2) with no differences in postoperative complications. Patients with COVID-associated acute respiratory distress syndrome required longer times on extracorporeal membrane oxygenation pretransplant (P = .02), but duration of extracorporeal membrane oxygenation support was not a predictor of 1-year survival (P = .2).

CONCLUSIONS

Despite prolonged periods of pretransplant extracorporeal membrane oxygenation support, selected patients with acute respiratory distress syndrome can undergo lung transplant safely with acceptable short-term outcomes. Appropriate selection criteria and long-term implications require further analysis.

A fetal wound healing program after intrauterine bile duct injury may contribute to biliary atresia

BACKGROUND & AIMS

Biliary atresia (BA) is an obstructive cholangiopathy that initially affects the extrahepatic bile ducts (EHBDs) of neonates. The etiology is uncertain, but evidence points to a prenatal cause. Fetal tissues have increased levels of hyaluronic acid (HA), which plays an integral role in fetal wound healing. The objective of this study was to determine whether a program of fetal wound healing is part of the response to fetal EHBD injury.

METHODS

Mouse, rat, sheep, and human EHBD samples were studied at different developmental time points. Models included a fetal sheep model of prenatal hypoxia, human BA EHBD remnants and liver samples taken at the time of the Kasai procedure, EHBDs isolated from neonatal rats and mice, and spheroids and other models generated from primary neonatal mouse cholangiocytes.

RESULTS

A wide layer of high molecular weight HA encircling the lumen was characteristic of the normal perinatal but not adult EHBD. This layer, which was surrounded by collagen, expanded in injured ducts in parallel with extensive peribiliary gland hyperplasia, increased mucus production and elevated serum bilirubin levels. BA EHBD remnants similarly showed increased HA centered around ductular structures compared with age-appropriate controls. High molecular weight HA typical of the fetal/neonatal ducts caused increased cholangiocyte spheroid growth, whereas low molecular weight HA induced abnormal epithelial morphology; low molecular weight HA caused matrix swelling in a bile duct-on-a-chip device.

CONCLUSION

The fetal/neonatal EHBD, including in human EHBD remnants from Kasai surgeries, demonstrated an injury response with prolonged high levels of HA typical of fetal wound healing. The expanded peri-luminal HA layer may swell and lead to elevated bilirubin levels and obstruction of the EHBD.

IMPACT AND IMPLICATIONS

Biliary atresia is a pediatric cholangiopathy associated with high morbidity and mortality rates; although multiple etiologies have been proposed, the fetal response to bile duct damage is largely unknown. This study explores the fetal pathogenesis after extrahepatic bile duct damage, thereby opening a completely new avenue to study therapeutic targets in the context of biliary atresia.

Primary graft dysfunction after lung transplantation

PURPOSE OF REVIEW

Primary graft dysfunction (PGD) is a clinical syndrome occurring within the first 72 h after lung transplantation and is characterized clinically by progressive hypoxemia and radiographically by patchy alveolar infiltrates. Resulting from ischemia-reperfusion injury, PGD represents a complex interplay between donor and recipient immunologic factors, as well as acute inflammation leading to alveolar cell damage. In the long term, chronic inflammation invoked by PGD can contribute to the development of chronic lung allograft dysfunction, an important cause of late mortality after lung transplant.

RECENT FINDINGS

Recent work has aimed to identify risk factors for PGD, focusing on donor, recipient and technical factors both inherent and potentially modifiable. Although no PGD-specific therapy currently exists, supportive care remains paramount and early initiation of ECMO can improve outcomes in select patients. Initial success with ex-vivo lung perfusion platforms has been observed with respect to decreasing PGD risk and increasing lung transplant volume; however, the impact on survival is not well delineated.

SUMMARY

This review will summarize the pathogenesis and clinical features of PGD, as well as highlight treatment strategies and emerging technologies to mitigate PGD risk in patients undergoing lung transplantation.

Chronic hypoxemia induces mitochondrial respiratory complex gene expression in the fetal sheep brain

Objective

The molecular pathways underlying hypoxemia-induced alterations in neurodevelopment of infants with congenital heart disease have not been delineated. We used transcriptome analysis to investigate differential gene expression induced by hypoxemia in an ovine artificial-womb model.

Methods

Mid-gestation fetal sheep (median [interquartile range] 109 [107-112] days' gestation) were cannulated via the umbilical vessels, attached to a pumpless, low-resistance oxygenator circuit, and incubated in a sterile, fluid environment for 22 [21-23] days. Fetuses were maintained with an oxygen delivery of 20-25 mL/kg/min (normoxemia, n = 3) or 14-16 mL/kg/min (hypoxemia, n = 4). Transcriptional profiling by RNA sequencing was carried out on left frontal brains and hypoxemia-regulated genes were identified by differential gene expression analysis.

Results

A total of 228 genes whose expression was up or down regulated by ≥1.5-fold (false discovery rate ≤0.05) were identified. The majority of these genes were induced in hypoxemic animals compared to normoxemic controls, and functional enrichment analysis identified respiratory electron transport as a pathway strongly upregulated in the brain during chronic hypoxemia. Further examination of hypoxemia-induced genes showed robust induction of all 7 subunits of the mitochondrial NADH:ubiquinone oxidoreductase (complex I). Other hypoxemia-induced genes included cytochrome B, a component of complex III, and ATP6, ATP8, both of which are components of complex V.

Conclusions

Chronic fetal hypoxemia leads to upregulation of multiple mitochondrial respiratory complex genes critical for energy production and reactive oxygen species generation, including complex I. These data provide valuable insight into potential pathways involved in chronic hypoxemia-induced neuropathology and offers potential therapeutic targets for fetal neuroprotection in fetuses with congenital heart defects.

Outcomes for the superior cavopulmonary connection in children with hypoplastic left heart syndrome: a 30-year experience

OBJECTIVES

The objective of this study was to estimate hospital mortality and length of stay (LOS) for children with hypoplastic left heart syndrome undergoing superior cavopulmonary connection (SCPC).

METHODS

All hypoplastic left heart syndrome interstage survivors who underwent SCPC between 1 January 1988 and 31 December 2017 were included. The study period was divided into 4 eras based on changes in operative or medical management. Mortality rates were estimated using standard binomial proportions. Adjusted and unadjusted logistic regression models were used to identify risk factors for mortality and LOS.

RESULTS

The most common procedures for the cohort (n = 958) were Hemi-Fontan (57.3%) or Bidrectional Glenn shunt (35.7%). The mortality was 4.1% overall and decreased in all 3 later eras compared to era 1. Factors associated with mortality in a multiple covariate model included longer total support time, earlier gestational age, longer LOS at the Norwood Procedure and need for additional procedures. Overall, the median LOS was 7.0 days with a decrease from eras 1 to 2 and plateaued in eras 3 and 4. Predictors of longer LOS included genetic anomaly, longer Norwood LOS, additional procedures, lower weight at surgery and longer total support time. The type of SCPC was not associated with mortality or LOS.

CONCLUSIONS

In this large cohort of patients with hypoplastic left heart syndrome undergoing SCPC, hospital mortality has decreased significantly. LOS initially declined but plateaued in recent eras. The risk factors for mortality and longer LOS are related to patient and procedural complexity, especially the need for additional procedures at the time of SCPC.

Attrition between the superior cavopulmonary connection and the Fontan procedure in hypoplastic left heart syndrome

OBJECTIVE

We investigated the incidence and predictors of failure to undergo the Fontan in children with hypoplastic left heart syndrome who survived superior cavopulmonary connection.

METHODS

The cohort consists of all patients with hypoplastic left heart syndrome who survived to hospital discharge after superior cavopulmonary connection between 1988 and 2017. The primary outcome was attrition, which was defined as death, nonsuitability for the Fontan, or cardiac transplantation before the Fontan. Subjects were excluded if they were awaiting the Fontan, were lost to follow-up, or underwent biventricular repair. The study period was divided into 4 eras based on changes in operative or medical management. Attrition was estimated with 95% confidence intervals, and predictors were identified using adjusted, logistic regression models.

RESULTS

Of the 856 hospital survivors after superior cavopulmonary connection, 52 died, 7 were deemed unsuitable for Fontan, and 12 underwent or were awaiting heart transplant. Overall attrition was 8.3% (71/856). Attrition rate did not change significantly across eras. A best-fitting multiple logistic regression model was used, adjusting for superior cavopulmonary connection year and other influential covariates: right ventricle to pulmonary artery shunt at Norwood (P < .01), total support time at superior cavopulmonary connection (P < .01), atrioventricular valve reconstruction at superior cavopulmonary connection (P = .02), performance of other procedures at superior cavopulmonary connection (P = .01), and length of stay after superior cavopulmonary connection (P < .01).

CONCLUSIONS

In this study spanning more than 3 decades, 8.3% of children with hypoplastic left heart syndrome failed to undergo the Fontan after superior cavopulmonary connection. This attrition rate has not decreased over 30 years. Use of a right ventricle to pulmonary artery shunt at the Norwood procedure was associated with increased attrition.

Decreasing Interstage Mortality After the Norwood Procedure: A 30-Year Experience

Background

The superior cavo‐pulmonary connection was introduced at our institution in 1988 for infants undergoing surgery for hypoplastic left heart syndrome. Patients with hypoplastic left heart syndrome remain at high risk for mortality in the time period between the Norwood procedure and the superior cavo‐pulmonary connection. The primary objectives of this study were to compare interstage mortality across 4 eras and analyze factors that may impact interstage mortality.

Methods and Results

Patients with hypoplastic left heart syndrome who underwent the Norwood procedure, were discharged from the hospital, and were eligible for superior cavo‐pulmonary connection between January 1, 1988, and December 31, 2017, were included. The study period was divided into 4 eras based on changes in operative or medical management. Mortality rates were estimated with 95% CIs. Adjusted and unadjusted logistic regression models were used to identify risk factors for mortality. There were 1111 patients who met the inclusion criteria. Overall, interstage mortality was 120/1111 (10.8%). Interstage mortality was significantly lower in era 4 relative to era 1 (4.6% versus 13.4%; P=0.02) during the time that age at the superior cavo‐pulmonary connection was the lowest (135 days; P<0.01) and the interstage monitoring program was introduced. In addition, use of the right ventricle to pulmonary artery shunt was associated with decreased interstage mortality (P=0.02) and was more routinely practiced in era 4.

Conclusions

During this 30‐year experience, the risk of interstage mortality decreased significantly in the most recent era. Factors that coincide with this finding include younger age at superior cavo‐pulmonary connection, introduction of an interstage monitoring program, and increased use of the right ventricle to pulmonary artery shunt.

In vivo-expressed genes of Pasteurella multocida

Pasteurella multocida is the causative agent of infectious diseases of economic importance such as fowl cholera, bovine hemorrhagic septicemia, and porcine atrophic rhinitis. However, knowledge of the molecular mechanisms and determinants that P. multocida requires for virulence and pathogenicity is still limited. To address this issue, we developed a genetic expression system, based on the in vivo expression technology approach first described by Mahan et al. (Science 259:686--688, 1993), to identify in vivo-expressed genes of P. multocida. Numerous genes, such as those encoding outer membrane lipoproteins, metabolic and biosynthetic enzymes, and a number of hypothetical proteins, were identified. These may prove to be useful targets for attenuating mutation and/or warrant further investigation for their roles in immunity and/or pathogenesis.

Characterisation of a Pasteurella multocida esterase gene which confers a hemolytic phenotype in Escherichia coli under anaerobic conditions

Investigation of the hemolytic phenotype under anaerobic growth conditions of an avian Pasteurella multocida strain, PBA100, resulted in the identification and characterisation of a gene encoding an esterase enzyme, mesA, that conferred a hemolytic phenotype in Escherichia coli under anaerobic conditions. MesA appeared to be expressed and functional under anaerobic and aerobic conditions in both E. coli and P. multocida. A P. multocida mesA mutant was generated which resulted in the loss of acetyl esterase activity under anaerobic conditions. However, this mutation did not cause any attenuation of virulence for mice nor a detectable change to the anaerobic hemolytic phenotype of P. multocida. In E. coli MesA appeared to cause hemolysis indirectly by the induction of the latent E. coli K-12 cytolysin, sheA.

The molecular biology of pasteurella multocida

Pasteurella multocida is an important veterinary and opportunistic human pathogen. The species is diverse and complex with respect to antigenic variation, host predeliction and pathogenesis. Certain serological types are the aetiologic agents of severe pasteurellosis, such as fowl cholera in domestic and wild birds, bovine haemorrhagic septicaemia and porcine atrophic rhinitis. The recent application of molecular methods such as the polymerase chain reaction, restriction endonuclease analysis, ribotyping, pulsed-field gel electrophoresis, gene cloning, characterisation and recombinant protein expression, mutagenesis, plasmid and bacteriophage analysis and genomic mapping, have greatly increased our understanding of P. multocida and has provided researchers with a number of molecular tools to study pathogenesis and epidemiology at a molecular level.

Cloning and characterisation of the Pasteurella multocida ahpA gene responsible for a haemolytic phenotype in Escherichia coli

Haemolysins are membrane-damaging agents which have been described as bacterial virulence factors due to their ability to lyse erythrocytes and other host cells, and therefore inducing a greater inflammatory response (Elliott et al., 1998). Pasteurella multocida was found to be haemolytic under anaerobic conditions. In this study, we cloned and characterised a P. multocida gene, designated ahpA, which conferred a haemolytic phenotype on Escherichia coli when incubated under anaerobic conditions. A deletion was introduced into the ahpA open reading frame which abolished the haemolytic phenotype. The clone containing ahpA showed erythrocyte specificity, causing haemolysis of bovine and equine erythrocytes, and demonstrated weak haemolysis on ovine erythrocytes. Upon further investigation, AhpA was found to affect the expression of the E. coli K-12 latent haemolysin, SheA, under anaerobic conditions.

Physical and genetic map of the Pasteurella multocida A:1 chromosome

A physical and genetic map of the Pasteurella multocida A:1 genome was generated by using the restriction enzymes ApaI, CeuI, and NotI. The positions of 23 restriction sites and 32 genes, including 5 rrn operons, were localized on the 2.35-Mbp single circular chromosome. This report presents the first genetic and physical map for this genus.

Intravenous medication errors

In a clinical study, it was reported that based on the number of adult patients admitted to two hospitals, medication errors amounted to almost 4,000, an alarming figure considering that many were thought to be preventable. Today's healthcare environment dictates the type of care patients receive and from whom, and the potential for medication errors. This article discusses the factors concerning the prescribing of i.v. medications, preparing the medications, and administering them competently by nurses and pharmacists.

Use of financial reports in managing pharmacies

The use of financial reports for preparing and monitoring the pharmacy budget is reviewed. Internal reports are generated within the department or hospital and are used to compare actual financial performance with budgeted projections. External reports are usually prepared by outside agencies and are used to compare the productivity, operations, and financial performance of one hospital with others in a predetermined group. The level of detail used in preparing financial reports determines the level of detail that can be used to monitor the budget. Internal reports on revenue, nonlabor expense, and labor expense are discussed, and the limitations of external reports comparing hospitals are presented. Effective use of financial reports is important in accurate budget forecasting, and pharmacy managers must seek out the financial information that will be of most value to them.

System to measure the use of pharmacy personnel

The development of a program to monitor the use of pharmacy personnel is described. The program is part of a hospital-wide Labor Information System developed to support requests for additional staff, to highlight opportunities for improved and allocation of manpower, and to serve as a conceptual model of the department from a manpower perspective when communicating with other members of the hospital organization. Nine major functions of the pharmacy department were identified. Detailed activities for each function were listed along with the type of personnel who performed each activity. Standards representing the amount of time spent on each activity were then developed. Variable, fixed, and open standards were used. Workload volumes are tabulated on a biweekly basis and entered into a computer. Payroll data covering the same period are simultaneously fed into the computer system. The resulting computer-generated report compares the service hours necessary to perform the actual workload (based on the predetermined time standards) to the available hours actually worked by each job category of pharmacy personnel. The ratio of service hours to available hours measures the use of personnel by functional activity. The system has been successfully applied to support requests for additional personnel, to forecast staffing needs for new programs, and to make operational improvements. In addition, the system has the capacity to accurately monitor personnel time for providing clinical services.