Recent Advances in the Genetic Pathogenesis, Diagnosis, and Management of Esophageal Atresia and Tracheoesophageal Fistula: A Review.

Infants born with esophageal atresia and tracheoesophageal fistula, a complex congenital malformation occurring in 1/2500-4000 live births, may suffer threats to their cardiac, respiratory, and digestive health in addition to anomalies that may exist in the genitourinary and musculoskeletal systems. Optimal care for these patients throughout their lives is best achieved through a coordinated, multidisciplinary approach that our health care system is not always well-equipped to provide. This review, though not exhaustive, highlights the components of care that pertain to initial surgical reconstruction and subsequent diagnosis and management of the complications that are most frequently encountered. Authors from among the many specialties involved in the care of these patients summarize the current best practice with attention to the most recent advances. Assessment and improvement of quality of life and transition to adult specialists as children grow to adulthood is also reviewed.

Fibrous hamartoma of infancy: imaging findings.

BACKGROUND: Fibrous hamartoma of infancy is a benign tumor that typically arises within the first 2 years of life in the subcutaneous and lower dermal layers. Diagnosis can be challenging as it is a rare tumor, and the imaging appearance is not well known. OBJECTIVE: To describe the imaging features in 4 cases of fibrous hamartoma of infancy focusing on ultrasound (US) and magnetic resonance (MR) findings. MATERIALS AND METHODS: In this retrospective IRB-approved study, informed consent was waived. We searched patient charts for histopathology-confirmed fibrous hamartoma of infancy diagnosis between November 2013 and November 2022. We found four cases, three boys and one girl, and the mean age was 1.4 years (5 months-3 years). The lesions were located in the axilla, posterior elbow, posterior neck, and lower back. All four patients underwent ultrasound evaluation of the lesion, and two patients also underwent MRI evaluation. The imaging findings were reviewed by consensus by two pediatric radiologists. RESULTS: US imaging revealed subcutaneous lesions with variably defined hyperechoic regions and intervening hypoechoic bands resulting in a linear "serpentine" pattern or a "multiple semicircle" pattern. MR imaging evidenced heterogeneous soft tissue masses, localized in the subcutaneous fat, and showed hyperintense fat interspersed with hypointense septations on both T1- and T2-weighted images. CONCLUSION: Fibrous hamartoma of infancy has a suggestive appearance on US with heterogeneous, echogenic subcutaneous lesions with intervening hypoechoic portions, in parallel or circumferential arrangement that can be seen as a serpentine or semicircular pattern. On MRI, interspersed macroscopic fatty components show high signal intensity on T1- and T2-weighted images and reduced signal on fat-suppressed inversion recovery images, with irregular peripheral enhancement.

Esophageal Surveillance Practices in Esophageal Atresia Patients: A Survey by the Eastern Pediatric Surgery Network.

INTRODUCTION: Endoscopic surveillance guidelines for patients with repaired esophageal atresia (EA) rely primarily on expert opinion. Prior to embarking on a prospective EA surveillance registry, we sought to understand EA surveillance practices within the Eastern Pediatric Surgery Network (EPSN). METHODS: An anonymous, 23-question Qualtrics survey was emailed to 181 physicians (surgeons and gastroenterologists) at 19 member institutions. Likert scale questions gauged agreement with international EA surveillance guideline-derived statements. Multiple-choice questions assessed individual and institutional practices. RESULTS: The response rate was 77%. Most respondents (80%) strongly agree or agree that EA surveillance endoscopy should follow a set schedule, while only 36% claimed to perform routine upper GI endoscopy regardless of symptoms. Many institutions (77%) have an aerodigestive clinic, even if some lack a multi-disciplinary EA team. Most physicians (72%) expressed strong interest in helping develop evidence-based guidelines. CONCLUSIONS: Our survey reveals physician agreement with current guidelines but weak adherence. Surveillance methods vary greatly, underscoring the lack of evidence-based data to guide EA care. Aerodigestive clinics may help implement surveillance schedules. Respondents support evidence-based protocols, which bodes well for care standardization. Results will inform the first multi-institutional EA databases in the United States (US), which will be essential for evidence-based care. LEVEL OF EVIDENCE: This is a prognosis study with level 4 evidence.

Management of Adults With Esophageal Atresia.

Esophageal atresia (EA) with or without trachea-esophageal fistula is relatively common congenital malformation with most patients living into adulthood. As a result, care of the adult patient with EA is becoming more common. Although surgical repair has changed EA from a fatal to a livable condition, the residual effects of the anomaly may lead to a lifetime of complications. These include effects related to the underlying deformity such as atonicity of the esophageal segment, fistula recurrence, and esophageal cancer to complications of the surgery including anastomotic stricture, gastroesophageal reflux, and coping with an organ transposition. This review discusses the occurrence and management of these conditions in adulthood and the role of an effective transition from pediatric to adult care to optimize adult care treatment.

Hybrid lung lesions in children with segmental infantile hemangiomas, a new association?

Infantile hemangiomas (IHs) are the most common tumors of infancy and, in rare instances, can present in the setting of congenital structural anomalies or as part of syndromic disorders. In this study, we present three cases of children with segmental IHs born with concurrent pulmonary anomalies: congenital pulmonary airway malformations and bronchopulmonary sequestration. To date, no known association between these entities and hemangiomas has been described.

Erratum: Identification and validation of candidate risk genes in endocytic vesicular trafficking associated with esophageal atresia and tracheoesophageal fistulas.

[This corrects the article DOI: 10.1016/j.xhgg.2022.100107.].

Pediatric surgery milestones 2.0: A primer.

More than twenty years ago, the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties began the conversion of graduate medical education from a structure- and process-based model to a competency-based framework. The educational outcomes assessment tool, known as the Milestones, was introduced in 2013 for seven specialties and by 2015 for the remaining specialties, including pediatric surgery. Designed to be an iterative process with improvements over time based on feedback and evidence-based literature, the Milestones started the evolution from 1.0 to 2.0 in 2016. The formation of Pediatric Surgery Milestones 2.0 began in 2019 and was finalized in 2021 for implementation in the 2022-2023 academic year. Milestones 2.0 are fewer in number and are stated in more straightforward language. It incorporated the harmonized milestones, subcompetencies for non-patient care and non-medical knowledge that are consistent across all medical and surgical specialties. There is a new Supplemental Guide that lists examples, references and links to other assessment tools and resources for each subcompetency. Milestones 2.0 represents a continuous process of feedback, literature review and revision with goals of improving patient care and maintaining public trust in graduate medical education's ability to self-regulate. LEVEL OF EVIDENCE: V.

Identification and validation of candidate risk genes in endocytic vesicular trafficking associated with esophageal atresia and tracheoesophageal fistulas.

Esophageal atresias/tracheoesophageal fistulas (EA/TEF) are rare congenital anomalies caused by aberrant development of the foregut. Previous studies indicate that rare or de novo genetic variants significantly contribute to EA/TEF risk, and most individuals with EA/TEF do not have pathogenic genetic variants in established risk genes. To identify the genetic contributions to EA/TEF, we performed whole genome sequencing of 185 trios (probands and parents) with EA/TEF, including 59 isolated and 126 complex cases with additional congenital anomalies and/or neurodevelopmental disorders. There was a significant burden of protein-altering de novo coding variants in complex cases (p = 3.3 × 10-4), especially in genes that are intolerant of loss-of-function variants in the population. We performed simulation analysis of pathway enrichment based on background mutation rate and identified a number of pathways related to endocytosis and intracellular trafficking that as a group have a significant burden of protein-altering de novo variants. We assessed 18 variants for disease causality using CRISPR-Cas9 mutagenesis in Xenopus and confirmed 13 with tracheoesophageal phenotypes. Our results implicate disruption of endosome-mediated epithelial remodeling as a potential mechanism of foregut developmental defects. Our results suggest significant genetic heterogeneity of EA/TEF and may have implications for the mechanisms of other rare congenital anomalies.

Extracorporeal Membrane Oxygenation (ECMO) and its complications in newborns with congenital diaphragmatic hernia.

BACKGROUND: Extracorporeal Membrane Oxygenation (ECMO) is offered to patients with congenital diaphragmatic hernia (CDH) who are in severe respiratory and cardiac failure. We aim to describe the types of complications among these patients and their impact on survival. METHODS: A single-center, retrospective review of CDH patients cannulated onto ECMO between January 2005 and November 2020 was conducted. ECMO complications, as categorized by the Extracorporeal Life Support Organization (ELSO), were correlated with survival status. Descriptive statistics were used to compare observed complications between survivors and non-survivors. RESULTS: In our cohort of CDH neonates, 21% (54/258) were supported with ECMO, of whom, 61% (33/54) survived. Survivors and non-survivors were similar in baseline characteristics except for birthweight z-score (p = 0.043). Seventy percent of CDH neonates experienced complications during their ECMO run, with the most common categories being metabolic (48.1%) and mechanical (38.9%), followed by hemorrhage (22.2%), neurological (18.5%), renal (11.1%), pulmonary (7.4%), and cardiovascular (7.4%). The median number of complications per patient was higher in the non-survivor group  (2 (IQR: 1-4) vs 1 (IQR: 0-2), p = 0.043). In addition, mechanical (57.1% vs 27.3%, p = 0.045) and renal (28.6% vs 0%, p = 0.002) complications were more common among non-survivors compared to survivors. CONCLUSION: Complications occur frequently among ECMO-treated newborns with CDH, some of which have serious long-term consequences. Survivors had higher birth weight z-scores, shorter ECMO runs, and fewer complications per patient. Mechanical and renal complications were independently associated with mortality, emphasizing the utility of more focused strategies to target fluid balance and renal protection and to prevent circuit and cannula complications.

Ethics in the Era of COVID-19.

The COVID-19 pandemic has led to new ethical challenges and exposed or exacerbated others that were already present. Through the lens of pediatric surgery, this article aims to discuss issues that have been impacted by the pandemic including triage of care and allocation of scarce resources, equity and access to care, and a physician's competing responsibilities to their patients, families, and selves.

Extracorporeal Membrane Oxygenation for Coronavirus Disease 2019: Crisis Standards of Care.

The coronavirus disease 2019 (COVID-19) pandemic has placed extraordinary strain on global healthcare systems. Use of extracorporeal membrane oxygenation (ECMO) for patients with severe respiratory or cardiac failure attributed to COVID-19 has been debated due to uncertain survival benefit and the resources required to safely deliver ECMO support. We retrospectively investigated adult patients supported with ECMO for COVID-19 at our institution during the first 80 days following New York City's declaration of a state of emergency. The primary objective was to evaluate survival outcomes in patients supported with ECMO for COVID-19 and describe the programmatic adaptations made in response to pandemic-related crisis conditions. Twenty-two patients with COVID-19 were placed on ECMO during the study period. Median age was 52 years and 18 (81.8%) were male. Twenty-one patients (95.4%) had severe ARDS and seven (31.8%) had cardiac failure. Fifteen patients (68.1%) were managed with venovenous ECMO while 7 (31.8%) required arterial support. Twelve patients (54.5%) were transported on ECMO from external institutions. Twelve patients were discharged alive from the hospital (54.5%). Extracorporeal membrane oxygenation was used successfully in patients with respiratory and cardiac failure due to COVID-19. The continued use of ECMO, including ECMO transport, during crisis conditions was possible even at the height of the COVID-19 pandemic.

A novel unidirectional-valved shunt approach for end-stage pulmonary arterial hypertension: Early experience in adolescents and adults.

OBJECTIVES: Despite advances in treatment of idiopathic pulmonary arterial hypertension (IPAH), there remains no medical cure, and patients can experience disease progression leading to right heart failure, progressive exercise intolerance, and death. The reversed Potts shunt (left pulmonary artery to descending aorta) was reintroduced for treatment of end-stage IPAH to permit decompression of the suprasystemic right ventricle by right to left shunting, with preservation of upper body oxygenation. The shunt has the potential to delay the need for lung transplantation and offer a treatment for those who are transplant ineligible. To optimize shunt design and avoid the potential complications of bidirectional shunting, we developed a novel approach using a unidirectional-valved shunt (UVS) in patients with IPAH with suprasystemic pulmonary arterial pressure and poor right ventricular function. METHODS: A single-center retrospective review was performed of UVS cases done at Columbia University Medical Center-New York Presbyterian between November 1, 2016, and May 1, 2019. RESULTS: Five patients (4 female; ages 12-22 years) underwent UVS. All had suprasystemic pulmonary arterial pressure, poor right ventricular function, and World Health Organization functional class IV symptoms at baseline. All patients are alive and transplant-free at latest follow-up (range 3-33 months; median 6 ± 11 months). CONCLUSIONS: The UVS may offer an alternative solution to lung transplantation in adolescents and young adults with IPAH. Longer-term follow-up is needed to determine the ultimate impact of unidirectional unloading of the right ventricle in these patients and to determine whether the UVS will enable a broader approach to the treatment of patients with IPAH.

Novel candidate genes in esophageal atresia/tracheoesophageal fistula identified by exome sequencing.

The various malformations of the aerodigestive tract collectively known as esophageal atresia/tracheoesophageal fistula (EA/TEF) constitute a rare group of birth defects of largely unknown etiology. Previous studies have identified a small number of rare genetic variants causing syndromes associated with EA/TEF. We performed a pilot exome sequencing study of 45 unrelated simplex trios (probands and parents) with EA/TEF. Thirteen had isolated and 32 had nonisolated EA/TEF; none had a family history of EA/TEF. We identified de novo variants in protein-coding regions, including 19 missense variants predicted to be deleterious (D-mis) and 3 likely gene-disrupting (LGD) variants. Consistent with previous studies of structural birth defects, there is a trend of increased burden of de novo D-mis in cases (1.57-fold increase over the background mutation rate), and the burden is greater in constrained genes (2.55-fold, p = 0.003). There is a frameshift de novo variant in EFTUD2, a known EA/TEF risk gene involved in mRNA splicing. Strikingly, 15 out of 19 de novo D-mis variants are located in genes that are putative target genes of EFTUD2 or SOX2 (another known EA/TEF gene), much greater than expected by chance (3.34-fold, p value = 7.20e-5). We estimated that 33% of patients can be attributed to de novo deleterious variants in known and novel genes. We identified APC2, AMER3, PCDH1, GTF3C1, POLR2B, RAB3GAP2, and ITSN1 as plausible candidate genes in the etiology of EA/TEF. We conclude that further genomic analysis to identify de novo variants will likely identify previously undescribed genetic causes of EA/TEF.

Antifactor Xa Monitoring and Hematologic Complications of Pediatric Extracorporeal Membrane Oxygenation.

Hemorrhagic and thrombotic complications are a significant source of morbidity and mortality for pediatric patients on extracorporeal membrane oxygenation (ECMO). Optimal anticoagulation therapies and monitoring strategies remain unknown. In 2013, our institution changed the anticoagulation monitoring protocol from activated clotting time (ACT) to antifactor Xa (anti-Xa) levels. We conducted a retrospective review of patients who received anticoagulation management directed by ACT results (n = 96) or anti-Xa levels (n = 72) between January 2010 and March 2016. Hemorrhagic complications occurred in 25% of the ACT group and 39% of the anti-Xa group (p = 0.054). Thrombotic complications were observed in 12.5% of the ACT group and 14% of the anti-Xa group (p = 0.8). There was a greater incidence of extracorporeal cardiopulmonary resuscitations (E-CPR; 36% vs. 15%; p = 0.005) in the anti-Xa group as compared with the ACT group. Secondary analysis showed no difference in transfusion requirements for red blood cells (ml/kg; p = 0.32) or platelets (ml/kg; p = 0.32). There was no difference in average heparin infusion rates (unit/kg/hr) per cannulation (p = 0.17) between the groups. Management of anticoagulation based on anti-Xa levels appears to be as effective as management based on ACT results.

Delayed presentation and sub-optimal outcomes of pediatric patients with acute appendicitis during the COVID-19 pandemic.

OBJECTIVE: Early presentation and prompt diagnosis of acute appendicitis are necessary to prevent progression of disease leading to complicated appendicitis. We hypothesize that patients had a delayed presentation of acute appendicitis during the COVID-19 pandemic, which affected severity of disease on presentation and outcomes. PATIENTS AND METHODS: We conducted a retrospective review of all patients who were treated for acute appendicitis at Morgan Stanley Children's Hospital (MSCH) between March 1, 2020 and May 31, 2020 when the COVID-19 pandemic was at its peak in New York City (NYC). For comparison, we reviewed patients treated from March 1, 2019 to May 31, 2019, prior to the pandemic. Demographics and baseline patient characteristics were analyzed for potential confounding variables. Outcomes were collected and grouped into those quantifying severity of illness on presentation to our ED, type of treatment, and associated post-treatment outcomes. Fisher's Exact Test and Kruskal-Wallis Test were used for univariate analysis while cox regression with calculation of hazard ratios was used for multivariate analysis. RESULTS: A total of 89 patients were included in this study, 41 patients were treated for appendicitis from March 1 to May 31 of 2019 (non-pandemic) and 48 were treated during the same time period in 2020 (pandemic). Duration of symptoms prior to presentation to the ED was significantly longer in patients treated in 2020, with a median of 2 days compared to 1 day (p = 0.003). Additionally, these patients were more likely to present with reported fever (52.1% vs 24.4%, p = 0.009) and had a higher heart rate on presentation with a median of 101 beats per minute (bpm) compared to 91 bpm (p = 0.040). Findings of complicated appendicitis on radiographic imaging including suspicion of perforation (41.7% vs 9.8%, p < 0.001) and intra-abdominal abscess (27.1% vs 7.3%, p = 0.025) were higher in patients presenting in 2020. Patients treated during the pandemic had higher rates of non-operative treatment (25.0% vs 7.3%, p = 0.044) requiring increased antibiotic use and image-guided percutaneous drain placement. They also had longer hospital length of stay by a median of 1 day (p = 0.001) and longer duration until symptom resolution by a median of 1 day (p = 0.004). Type of treatment was not a predictor of LOS (HR = 0.565, 95% CI = 0.357-0.894, p = 0.015) or duration until symptom resolution (HR = 0.630, 95% CI = 0.405-0.979, p = 0.040). CONCLUSION: Patients treated for acute appendicitis at our children's hospital during the peak of the COVID-19 pandemic presented with more severe disease and experienced suboptimal outcomes compared to those who presented during the same time period in 2019. LEVEL OF EVIDENCE: III.

Allocation of resources and development of guidelines for extracorporeal membrane oxygenation (ECMO): Experience from a pediatric center in the epicenter of the COVID-19 pandemic.

The rapid spread of coronavirus disease 2019 (COVID-19) has exceeded the standard capacity of many hospital systems and led to an unprecedented scarcity of resources, including the already limited resource of extracorporeal membrane oxygenation (ECMO). With the large amount of critically ill patients and the highly contagious nature of the virus, significant consideration of ECMO candidacy is crucial for both appropriate allocation of resources as well as ensuring protection of health care personnel. As a leading pediatric ECMO program in the epicenter of the pandemic, we established new protocols and guidelines in order to continue caring for our pediatric patients while accepting adult patients to lessen the burden of our hospital system which was above capacity. This article describes our changes in consultation, cannulation, and daily care of COVID-19 positive patients requiring ECMO as well as discusses strategies for ensuring safety of our ECMO healthcare personnel and optimal allocation of resources. LEVEL OF EVIDENCE: Level V.

Neonates With Complex Cardiac Malformation and Congenital Diaphragmatic Hernia Born to SARS-CoV-2 Positive Women-A Single Center Experience.

BACKGROUND: Our understanding of the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on pregnancies and perinatal outcomes is limited. The clinical course of neonates born to women who acquired coronavirus disease 2019 (COVID-19) during their pregnancy has been previously described. However, the course of neonates born with complex congenital malformations during the COVID-19 pandemic is not known. METHODS: We report a case series of seven neonates with congenital heart and lung malformations born to women who tested positive for SARS-CoV-2 during their pregnancy at a single academic medical center in New York City. RESULTS: Six infants had congenital heart disease and one was diagnosed with congenital diaphragmatic hernia. In all seven infants, the clinical course was as expected for the congenital lesion. None of the seven exhibited symptoms generally associated with COVID-19. None of the infants in our case series tested positive by nasopharyngeal test for SARS-CoV-2 at 24 hours of life and at multiple points during their hospital course. CONCLUSIONS: In this case series, maternal infection with SARS-CoV-2 during pregnancy did not result in adverse outcomes in neonates with complex heart or lung malformations. Neither vertical nor horizontal transmission of SARS-CoV-2 was noted.

Development of pediatric surgical decision-making guidelines for COVID-19 in a New York City children's hospital.

OBJECTIVE: During the COVID-19 pandemic, experience-based guidelines are needed in the pediatric population in order to deliver high quality care in a new way that keeps patients and healthcare workers safe and maximizes hospital resource utilization. BACKGROUND: The COVID-19 pandemic has created an unprecedented strain on national health care resources, particularly in New York City, the epicenter of the outbreak in the United States. Prudent allocation of surgical resources during the pandemic quickly became essential, and there is an unprecedented need to weigh the risks of operating versus delaying intervention in our pediatric patients. METHODS: Here we describe our experience in surgical decision-making in the pediatric surgical population at Morgan Stanley Children's Hospital of New York-Presbyterian (MSCHONY), which has served as a major urban catchment area for COVID-19 positive pediatric patients. We describe how we have adjusted our current treatment of multiple facets of pediatric surgery including oncology, trauma, minimally invasive procedures, and extracorporeal membrane oxygenation (ECMO). CONCLUSIONS: Our pediatric surgery department had to creatively and expeditiously adjust our protocols, guidelines, and workforce to not only serve our pediatric population but merge ourselves with our adult hospital system during the COVID pandemic. TYPE OF STUDY: Clinical research paper LEVEL OF EVIDENCE: Level V.

Characterization of Extracorporeal Membrane Oxygenation Support for Single Ventricle Patients.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) can provide crucial support for single ventricle (SV) patients at various stages of palliation. However, characterization of the utilization and outcomes of ECMO in these unique patients remains incompletely studied. METHODS: We performed a single-center retrospective review of SV patients between 2010 and 2017 who underwent ECMO cannulation with primary end point of survival to discharge and secondary end point of survival to decannulation or orthotopic heart transplantation (OHT). Multivariate analysis was performed for factors predictive of survival to discharge and survival to decannulation. RESULTS: Forty SV patients with a median age of one month (range: 3 days to 15 years) received ECMO support. The incidence of ECMO was 14% for stage I, 3% for stage II, and 4% for stage III. Twenty-seven (68%) patients survived to decannulation, and 21 (53%) patients survived to discharge, with seven survivors to discharge undergoing OHT. Complications included infection (40%), bleeding (40%), thrombosis (33%), and radiographic stroke (45%). Factors associated with survival to decannulation included pre-ECMO lactate (hazard ratio [HR]: 0.61, 95% confidence interval [CI]: 0.41-0.90, P = .013) and post-ECMO bicarbonate (HR: 1.24, 95% CI: 1.0-1.5, P = .018). Factors associated with survival to discharge included central cannulation (HR: 40.0, 95% CI: 3.1-500.0, P = .005) and lack of thrombotic complications (HR: 28.7, 95% CI: 2.1-382.9, P = .011). CONCLUSIONS: Extracorporeal membrane oxygenation can be useful to rescue SV patients with approximately half surviving to discharge, although complications are frequent. Early recognition of the role of heart transplant is imperative. Further study is required to identify areas for improvement in this population.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke.

BACKGROUND AND PURPOSE: Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics. METHODS: Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories. RESULTS: We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures. CONCLUSIONS: Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.