Association of dead space ventilation and prolonged ventilation after repair of tetralogy of Fallot with pulmonary atresia

Human phenotype ontology annotation and cluster analysis for pulmonary atresia to unravel clinical outcomes

Background

Pulmonary atresia (PA) is a heterogeneous congenital heart defect and ventricular septal defect (VSD) is the most vital factor for the conventional classification of PA patients. The simple dichotomy could not fully describe the cardiac morphologies and pathophysiology in such a complex disease. We utilized the Human Phenotype Ontology (HPO) database to explore the phenotypic patterns of PA and the phenotypic influence on prognosis.

Methods

We recruited 786 patients with diagnoses of PA between 2008 and 2016 at Fuwai Hospital. According to cardiovascular phenotypes of patients, we retrieved 52 HPO terms for further analyses. The patients were classified into three clusters based on unsupervised hierarchical clustering. We used Kaplan–Meier curves to estimate survival, the log-rank test to compare survival between clusters, and univariate and multivariate Cox proportional hazards regression modeling to investigate potential risk factors.

Results

According to HPO term distribution, we observed significant differences of morphological abnormalities in 3 clusters. We defined cluster 1 as being associated with Tetralogy of Fallot (TOF), VSD, right ventricular hypertrophy (RVH), and aortopulmonary collateral arteries (ACA). ACA was not included in the cluster classification because it was not an HPO term. Cluster 2 was associated with hypoplastic right heart (HRH), atrial septal defect (ASD) and tricuspid disease as the main morphological abnormalities. Cluster 3 presented higher frequency of single ventricle (SV), dextrocardia, and common atrium (CA). The mortality rate in cluster 1 was significantly lower than the rates in cluster 2 and 3 (p = 0.04). Multivariable analysis revealed that abnormal atrioventricular connection (AAC, p = 0.011) and persistent left superior vena cava (LSVC, p = 0.003) were associated with an increased risk of mortality.

Conclusions

Our study reported a large cohort with clinical phenotypic, surgical strategy and long time follow-up. In addition, we provided a precise classification and successfully risk stratification for patients with PA.

Perioperative and Anesthetic Considerations in Tetralogy of Fallot With Pulmonary Atresia

Tetralogy of Fallot with pulmonary atresia (ToF-PA) is a rare diagnosis that includes an extraordinarily heterogeneous group of complex anatomical findings with significant implications for physiology and prognosis. In addition to the classic findings of ToF, this particular diagnosis is characterized by complete failure of forward flow from the right ventricle to the pulmonary arterial system. As such, pulmonary blood flow is entirely dependent on shunting from the systemic circulation, most frequently via a patent ductus arteriosus, major aortopulmonary collaterals, or a combination of the two. The pathophysiology of ToF-PA is largely attributable to the abnormalities of the pulmonary vasculature. Ultimately, these patients require operative intervention to create a reliable, controlled source of pulmonary blood flow and ideally complete intracardiac repair. Even after operative correction, these patients remain at risk for pulmonary arterial stenoses and pulmonary hypertension. Although there have been significant advances in surgical and interventional management of ToF-PA leading to dramatic improvements in survival and long-term functional status, there is ongoing debate about the optimal management strategy given the risk of development of irreversible abnormalities of the pulmonary vasculature and the morbidity and mortality associated with sometimes multiple, complex operative interventions often occurring early in infancy. This review will discuss the findings in patients with ToF-PA with a focus on the perioperative and anesthetic management and will highlight challenges faced by the anesthesiologist in caring for these patients.

Prolonged Postoperative Mechanical Ventilation (PPMV) in children undergoing abdominal operations: An analysis of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database

BACKGROUND

Prolonged postoperative mechanical ventilation (PPMV) increases length of stay, hospitalization costs, and postoperative complications. Independent risk factors associated with PPMV are not well-known for children.

METHOD

We identified children (<18 years) in the ACS NSQIP-P database who underwent a general surgical abdominal operation. We excluded children with preoperative ventilator dependence and mortality within 48 h of surgery. PPMV was defined as cumulative postoperative mechanical ventilation exceeding 72 h. A multivariable logistic regression model identified independent predictors of PPMV.

RESULTS

We identified 108,392 children who underwent a general surgical abdominal operation in the ACS NSQIP-P database from 2012 to 2017. We randomly divided the population into a derivation cohort of 75,874(70%) and a validation cohort of 32,518(30%). In the derivation cohort, we identified PPMV in 1,643(2.2%). In the multivariable model, the strongest independent predictor of PPMV was neonatal age (OR:20.66; 95%CI:16.44-25.97). Other independent risk factors for PPMV were preoperative inotropic support (OR:10.56; 95%CI:7.56-14.77), an operative time longer than 150 min (OR:4.30; 95%CI:3.72-4.52), and an American Society of Anesthesiologists classification >3 (OR:12.16; 95%CI:10.75-13.75).

CONCLUSION

Independent preoperative risk factors for PPMV in children undergoing a general surgical operation were neonatal age, preoperative ionotropic support, duration of operation, and ASA classification >3.

Early extubation is associated with improved outcomes after complete surgical repair of pulmonary atresia with ventricular septal defect and hypoplastic pulmonary arteries in pediatric patients

BACKGROUND

The aim of this study was to investigate the impact of an early extubation strategy on outcomes following complete repair of pulmonary atresia, ventricular septal defect, and hypoplastic pulmonary artery.

METHODS

One hundred thirteen patients undergoing complete repair surgery of pulmonary atresia, ventricular septal defect, and hypoplastic pulmonary artery between 2016 and 2018 were included in our retrospective propensity-score matched study. Propensity score matching was conducted in 1 to 2 ratio to balance the covariables impacting on clinical outcomes between groups. The primary outcomes were defined as length of intensive care unit stay, postoperative length of hospital stay and in-hospital medical cost. The secondary outcomes included postoperative complications such as re-intubation, re-exploration, in-hospital mortality, arrhythmia and etc.. In addition, blood product consumption were also abstracted.

RESULTS

Compared with matched controls, patients in the early extubation group were demonstrated with a significant reduced length of intensive care unit stay (Median: 1.9 d νs. 4.1 d, p = 0.039), postoperative length of hospital stay (Median: 9.0 d νs. 17.0 d, p = 0.007) and in-hospital medical cost (Median: 69.5 × 1000CNY νs. 113.6× 1000CNY, p = 0.041). As for the postoperative complications, the occurrence of re-intubation, re-exploration, in-hospital mortality, arrhythmia and renal replacement therapy was similar between groups. However, pulmonary complications (p = 0.049) were with a significantly lower rate in the early extubation group. In addition, fresh frozen plasma (p = 0.041) transfusion volume were significantly reduced in the early extubation group rather than packed red blood cells and platelets.

CONCLUSIONS

Early extubation following complete repair of pulmonary atresia improved clinical outcomes and reduced in-hospital medical cost without increasing any postoperative complications.

The Use of Alveolar Dead Space Fraction to Predict Postoperative Outcomes after Pediatric Cardiac Surgery: A Retrospective Study

Patients with congenital heart disease (CHD) that have surgical repair with cardiopulmonary bypass (CPB) reflect a unique population with multiple pulmonary and systemic factors that may contribute to increased alveolar dead space and low cardiac output syndrome. This study aimed to assess and compare changes in the alveolar dead space fraction (AVDSf) in the immediate postoperative period with outcomes in children with CHD who underwent repair on CPB. A single-center retrospective review study of critically ill children with CHD, younger than 18 years of age admitted to the Pediatric Intensive Care Unit (PICU) after undergoing surgical repair on CPB and received invasive mechanical ventilation for at least 24 h. One hundred and two patients were included in the study. Over the first 24 h, mean AVDSf was significantly higher in patients who had longer hospital length of stay (LOS) (> 21 days) p = 0.02, and longer duration of invasive mechanical ventilation (DMV) (> 170 h) p = 0.01. Cross-sectional analyses at 23-24 h revealed that AVDSf > 0.25 predicts mortality and DMV (p = 0.03 and P = 0.02 respectively); however, it did not predict prolonged hospital LOS. For every 0.1 increase in the AVDSf, the odds of mortality, DMV, and hospital LOS increased by 4.9 [95% CI = 1.45-16.60, p = 0.002], 2.06 [95% CI = 1.14-3.71, p = 0.01], and 1.43[95% CI = 0.84-2.45, p = 0.184], respectively. The area under the ROC curve at 23-24 h for AVDSf was 0.868 to predict mortality as an outcome. AVDSf > 0.25 at 23-24 h postoperatively was an independent predictor of mortality with sensitivity and specificity of 83% and 80%, respectively and was superior to other commonly used surrogates of cardiac output. In the immediate postoperative period of pediatric patients with CHD, high AVDSf is associated with longer hospital length of stay and duration of invasive mechanical ventilation. Increased AVDSf values at 23-24 h postoperatively is associated with mortality in patients with CHD exposed to CPB.