Patricio E. Lau

Prenatal diagnosis and outcome of fetal gastrointestinal obstruction

INTRODUCTION The purpose of this study was to evaluate the accuracy of prenatal diagnosis for fetuses with gastrointestinal (GI) obstruction with correlation to postnatal outcomes. METHODS Fetuses diagnosed with GI obstruction (excluding esophageal and duodenal) were reviewed for those evaluated between 2006 and 2016. Prenatal diagnosis and imaging studies were compared to postnatal findings. Outcomes evaluated included diagnostic accuracy, rate of other anomalies, neonatal length of stay, incidence of short bowel syndrome, and discharge with TPN or gastrostomy. RESULTS Forty-eight patients were diagnosed prenatally with obstruction. Six patients were excluded owing to incomplete records and follow-up. Twelve fetuses were diagnosed with ultrasound alone, and thirty-four with ultrasound and MRI. A diagnosis of obstruction was accurate in 88.1% (n=37/42) with a positive predictive value of 91.3%, while US with MRI had an accuracy of 84.4%. Associated anomalies were highest among fetuses with anorectal obstruction (90.1%), compared to large (50%) or small bowel obstruction (28%). Survival rate was lowest for anorectal obstruction (54.5%), compared to large or small bowel obstruction (100% for both). CONCLUSION Fetal MRI is an accurate modality in the diagnosis of fetal GI obstruction and can complement findings characterized by ultrasound. Fetuses with anorectal obstruction have a higher rate of associated anomalies and the lowest survival. LEVEL OF EVIDENCE IIb.

Early vs late resection of asymptomatic congenital lung malformations

PURPOSE To examine postsurgical outcomes of a consecutive series of children treated with elective operations for congenital lung malformations (CLM). METHODS A retrospective review was performed on a prospectively collected dataset of all fetuses evaluated for a CLM between July 2001 and June 2016. Prenatal findings, operative treatment and postnatal outcomes were collected. Children having elective operations were divided in two groups based on age at time of surgery. RESULTS Of 220 fetuses, 143 had operations and follow-up at our center. Six had open fetal lobectomy, 17 had EXIT-to-resection, 16 infants had urgent resection for symptoms and 110 with asymptomatic lesions had elective resection. Of these 110, the median fetal maximum CVR was 0.8 [range 0.1-2.2], and median age at operation was 4 (1.5-60) months (58% had resection at ≤4 months). Overall complication rate, including air-leak and pleural effusion, was 15%. When comparing those having resection at ≤4 months to those >4 months, there were no significant differences in complication rates or length of stay. Operative time was shorter for patients with early resection (154 ± 59 vs 181 ± 89, p = 0.05). No infant having resection at ≤4 months was readmitted. Overall, children survived with good recovery. CONCLUSION Early elective resection of congenital lung malformations prior to 4 months of age is feasible and not associated with increased operative risk. TYPE OF STUDY Restropective study. LEVEL OF EVIDENCE Level III.

Necrotizing enterocolitis in patients with congenital heart disease: A single center experience

PURPOSE The purpose of this study was to evaluate the characteristics of patients with congenital heart disease (CHD) who developed necrotizing enterocolitis (NEC). METHODS A retrospective review of neonates with CHD at a tertiary care center between January 2006 and January 2016 was performed. Diagnosis of NEC was based on modified Bells criteria. Patients were grouped by Risk Adjustment for Congenital Heart Surgery (RACHS-1) or by ductal-dependent (DD) lesions that require a patent ductus arteriosus to supply pulmonary or systemic circulation. RESULTS Of 1811 neonates with CHD, 3.4% (n=61) developed NEC. Eighteen (30%) of these required surgical management. The rate of NEC among DD patients was 5% (n=33/653), compared to 2.4% (n=28/1158) in the non-DD group (p=0.003). RACHS-1 score>2 had a higher rate of NEC 6.2% (41/658) compared to RACHS-1≤2 cases, 1.7% (20/1153) (p=0.005). DD patients and complex patients with RACHS-1>2 were more likely to develop NEC after cardiac surgery. Hypoplastic left heart syndrome patients had a rate of 9% (n=16/185). Surgical NEC was more prevalent in the non-DD group. Mortality was similar among groups. CONCLUSION CHD patients with ductal-dependent lesions or complex cases (RACHS-1 score>2) have higher rates of NEC than non-ductal-dependent patients or RACHS-1 score of 2 or less. Mortality is similar regardless of ductal dependence, but surgical NEC was more prevalent in non-DD patients. LEVEL OF EVIDENCE Level IIb.

Predictive value of oxygenation index for outcomes in left-sided congenital diaphragmatic hernia

BACKGROUND & OBJECTIVES Congenital Diaphragmatic Hernia (CDH) is associated with significant morbidity and mortality. This study compares the efficacy of the highest oxygenation index in the first 48 h (HiOI) versus current prenatal indices to predict survival and morbidity. METHODS Medical records of 50 prenatally diagnosed, isolated, left-sided CDH patients treated from January 2011 to April 2016 were reviewed. Data abstracted included HiOI, lung to head ratio (LHR), observed to expected total fetal lung volume (O/E TFLV), percent liver herniation (%LH), 6 month survival, respiratory support at discharge, ventilator days and length of stay. Data were analyzed using parametric and nonparametric tests and regression analyses as appropriate. RESULTS HiOI was associated with significantly increased LOS (p<0.001), respiratory support at discharge (p<0.001), greater ventilator days (p=0.001) and higher odds of death (p=0.004) with risk of death increasing by 5% for every one-unit increase in OI. HiOI was statistically a better predictor of LOS than O/E TFLV (p=0.007) and %LH (p=0.02). CONCLUSIONS In isolated, left-sided CDH patients, HiOI is associated with higher mortality, greater length of stay, more ventilator days and increased respiratory support at discharge. HiOI is a better predictor of length of stay than O/E TFLV and %LH. TYPE OF STUDY Retrospective Study LEVEL OF EVIDENCE: II.

Prematurity reduces citrulline-arginine-nitric oxide production and precedes the onset of necrotizing enterocolitis in piglets

Necrotizing enterocolitis (NEC) is associated with low plasma arginine and vascular dysfunction. It is not clear whether low intestinal citrulline production, the precursor for arginine synthesis, occurs before and thus predisposes to NEC or if it results from tissue damage. This study was designed to test the hypothesis that whole body rates of citrulline, arginine, and nitric oxide synthesis are low in premature pigs and that they precede NEC. Piglets delivered by cesarean section at 103 days [preterm (PT)], 110 days [near-term (NT)], or 114 days [full-term (FT)] of gestation were given total parenteral nutrition and after 2 days orogastrically fed infant formula for 42 h to induce NEC. Citrulline and arginine fluxes were determined before and during the feeding protocol. Gross macroscopic and histological NEC scores and plasma fatty acid binding protein (iFABP) concentration were determined as indicators of NEC. Intestinal gene expression for enzymes of the arginine pathway were quantitated. A lower ( P < 0.05) survival rate was observed for PT (8/27) than for NT (9/9) and FT pigs (11/11). PT pigs had higher macroscopic gross ( P < 0.05) and histological NEC ( P < 0.05) scores and iFABP concentration ( P < 0.05) than pigs of more advanced gestational age. PT pigs had lower citrulline production and arginine fluxes ( P < 0.05) throughout and a reduced gene expression in genes of the citrulline-arginine pathway. In summary, intestinal enzyme expression and whole body citrulline and arginine fluxes were reduced in PT pigs compared with animals of more advance gestational age and preceded the development of NEC. NEW & NOTEWORTHY Arginine supplementation prevents necrotizing enterocolitis (NEC), the most common gastrointestinal emergency of prematurity. Citrulline (precursor for arginine) production is reduced during NEC, and this is believed to be a consequence of intestinal damage. In a swine model of NEC, we show that intestinal gene expression of the enzymes for citrulline production and whole body citrulline and arginine fluxes are reduced and precede the onset of NEC in premature pigs. Reduced citrulline production during prematurity may be a predisposition to NEC.

Use of renal near-infrared spectroscopy measurements in congenital diaphragmatic hernia patients on ECMO

INTRODUCTION This study tests the hypothesis that renal tissue oxygen saturation as measured by Near Infrared Spectroscopy (NIRS) would correlate with urine output in neonates with congenital diaphragmatic hernia (CDH) on extracorporeal membrane oxygenation (ECMO). METHODS Between 2012 and 2015, neonates with CDH were enrolled as part of a comprehensive study that provided renal/cerebral/abdominal NIRS monitoring for the duration of ECMO support. Continuous NIRS measurements, mean arterial pressure, and urine output were recorded. Periods of anuria (NU), adequate urine output >1ml/kg/h (AU), and low urine output <1ml/kg/h (LU) were noted and analyzed. RESULTS Over 1500h of continuous renal NIRS were obtained from six neonates. NIRS values were significantly different during periods of AU, LU, and anuria (84±6%, 76±3%, and 67±6%, p<0.01). ROC curves identified NIRS >76% as highly predictive of adequate urine output (AUC=0.96). MAP was significantly lower only in anuric patients, 36.42±10.26, compared to patients with AU and LU - 42.99±5.25 and 42.85±7.4, respectively (p<0.001). CONCLUSION Renal NIRS measurements correlate with urine production. Lower values are noted as urine output declines and precedes a decline in MAP. Renal NIRS may have promise as a non-invasive means of determining adequacy of renal perfusion and urine output in neonates with complex fluid shifts. LEVEL OF EVIDENCE IIb.

A novel multimodal computational system using near-infrared spectroscopy predicts the need for ECMO initiation in neonates with congenital diaphragmatic hernia

BACKGROUND/PURPOSE The purpose of this study was to develop a computational algorithm that would predict the need for ECMO in neonates with congenital diaphragmatic hernia (CDH). METHODS CDH patients from August 2010 to 2016 were enrolled in a study to continuously measure cerebral tissue oxygen saturation (cStO2) of left and right cerebral hemispheres. NIRS devices utilized were FORE-SIGHT, CASMED and INVOS 5100, Somanetics. Using MATLAB©, a data randomization function was used to deidentify and blindly group patients data files as follows: 12 for the computational model development phase (6 ECMO and 6 non-ECMO) and the remaining patients for the validation phase. RESULTS Of the 56 CDH patients enrolled, 22 (39%) required ECMO. During development of the algorithm, a difference between right and left hemispheric cerebral oxygenation via NIRS (ΔHCO) was noted in CDH patients that required ECMO. Using ROC analysis, a ΔHCO cutoff >10% was predictive of needing ECMO (AUC: 0.92; sensitivity: 85%; and specificity: 100%). The algorithm predicted need for ECMO within the first 12h of life and at least 6h prior to the clinical decision for ECMO with 88% sensitivity and 100% specificity. CONCLUSION This computational algorithm of cerebral NIRS predicts the need for ECMO in neonates with CDH. LEVEL OF EVIDENCE II.