Grant G. Miller

Reduced aluminum contamination decreases parenteral nutrition associated liver injury

PURPOSE Parenteral nutrition-associated cholestasis remains a significant problem, especially for the surgical neonates. Aluminum is a toxic element known to contaminate parenteral nutrition. We hypothesize that parenterally administered aluminum causes liver injury similar to that seen in parenteral nutrition-associated cholestasis. METHODS Twenty 3- to 6-day-old domestic pigs were divided into 5 equal groups. A control group received daily intravenous 0.9% NaCl. Each subject in experimental groups received intravenous aluminum chloride at 1500 μg kg(-1) d(-1) for 1, 2, 3, or 4 weeks. At the end of the study, blood was sampled for direct bilirubin and total bile acid levels. Liver, bile, and urine were sampled for aluminum content. Liver tissue was imaged by transmission electron microscopy for ultrastructural changes. RESULTS Transmission electron microscopy revealed marked blunting of bile canaliculi microvilli in all experimental subjects but not the controls. Serum total bile acids correlated with the duration of aluminum exposure. The hepatic aluminum concentration correlated with the duration of aluminum exposure. CONCLUSIONS Parenterally infused aluminum resulted in liver injury as demonstrated by elevated bile acids and by blunting of the bile canaliculi microvilli. These findings are similar to those reported in early parenteral nutrition-associated liver disease.

Zygomycotic infection of the neonatal upper extremity.

Zygomycosis is a rare fungal infection that may present as a necrotizing soft tissue infection in the neonate. This report illustrates the typical presentation of a premature, infant with a rapidly progressive soft tissue necrotizing infection of his upper extremity at an intravenous site. Early diagnosis with tissue biopsy confirmed the diagnosis of Zygomycosis. Successful treatment required systemic amphotercin B and aggressive debridement requiring through-the-elbow amputation for survival.

Outcomes following neonatal patent ductus arteriosus ligation done by pediatric surgeons: A retrospective cohort analysis

PURPOSE Patent Ductus Arteriosus (PDA) ligation in premature infants is an urgent procedure performed by some but not all pediatric surgeons. Proficiency in PDA ligation is not a requirement of Canadian pediatric surgery training. Our purpose was to determine the outcomes of neonatal PDA ligation done by pediatric surgeons. METHODS We performed a retrospective review of premature infants who underwent PDA ligation by pediatric surgeons in 3 Canadian centers from 2005 to 2009. Outcomes were compared to published controls. RESULTS The review identified 98 patients with a mean corrected GA and weight at repair of 29 weeks and 1122 g, respectively. There were no intraoperative deaths. The 30-day and inhospital mortality rates were 1% and 5%. Mortality and morbidity were comparable to the published outcomes. CONCLUSIONS This study documents that a significant number of preterm infant PDA ligations are safely done by pediatric surgeons. To meet the Canadian needs for this service by pediatric surgeons, proficiency in PDA ligation should be considered important in pediatric surgery training programs.

Infant Parenteral Nutrition Remains a Significant Source for Aluminum Toxicity

Background: Aluminum toxicity is associated with anemia, impaired bone metabolism, neurologic defects, and parenteral nutrition (PN)–associated liver disease. This element is a ubiquitous contaminant of PN components, especially in infant formulations. We assessed the current levels of aluminum contamination in infant PN at a level III neonatal intensive care unit. Materials and Methods: Thirty samples of PN prepared in the same hospital for infants aged <30 days (mean [SD] weight, 1.54 [0.71] kg) were collected from discarded solution. Each sample was analyzed for aluminum content via inductively coupled plasma mass spectrometry. The components of PN (from label) and measured aluminum content were then compared using linear regression and 1-way analysis of variance. Results: The mean (SD) aluminum contamination of infant PN was 14.02 (6.51) mcg/kg/d. Only 3 samples were <5 mcg/kg/d. Aluminum levels and infant weight were not associated. Linear regression revealed a significant correlation between aluminum and both calcium gluconate (P < .0001) and phosphate (P = .05), with a trend between aluminum and potassium (P = .07). Conclusions: Aluminum contamination in infant PN remains almost 3 times higher than the advised maximum exposure (<5 mcg/kg/d, Food and Drug Administration 2004). Unexpectedly, an association between infant weight and aluminum exposure was not apparent, likely due to the homogeneity of our population. Isolating the source of aluminum contamination is difficult, as multiple components appear to be involved. Calcium gluconate is likely still a major contributor, but further investigations into individual components are warranted to promote the reduction of aluminum in infant PN.

A survey-based assessment of the Canadian pediatric surgery workforce.

BACKGROUND There is significant lack of information regarding the Canadian pediatric surgery workforce. METHODS An IRB-approved survey aimed at assessing workforce issues was administered to pediatric surgeons and pediatric surgery chiefs in Canada in 2012. RESULTS The survey was completed by 98% of practicing surgeons and 13 of the 18 division chiefs. Only 6% of surgeons are older than 60 years, and only a fifth anticipate retirement over the next decade. The workforce is stable, with 82% of surgeons unlikely to change current positions. Surgical volume showed essentially no growth during the 5-year period 2006-2010. The majority of surgeons felt they were performing the right number or too few cases and anticipated minimal or no future growth in their individual practices or that of their group. Based on anticipated vacancies, the best estimate is a need for 20 new pediatric surgeons over the next decade. This need is significantly surpassed by the current output from the Canadian training programs. CONCLUSIONS The Canadian pediatric surgery workforce is currently saturated. The mismatch between the number of graduating trainees and the available positions over the next decade has significant repercussions for current surgery and pediatric surgery residents wishing to practice in Canada.

Peripheral venous pressure predicts central venous pressure poorly in pediatric patients

PurposeUsing peripheral venous pressure (PVP) instead of central venous pressure (CVP) as a volume monitor decreases patient risks and costs, and is convenient. This study was undertaken to determine if PVP predicts CVP in pediatric patients.MethodsWith ethical approval and informed consent, 30 pediatric patients aged neonate to 12 yr requiring a central venous line were studied prospectively in a tertiary care teaching hospital. In the supine position, PVP and CVP were simultaneously transduced. Ninety-six paired recordings of CVP and PVP were made. Correlation and Bland-Altman analysis of agreement of end-expiratory measurements were performed.ResultsThe mean (SD; range) CVP was 10.0 mmHg (6.0; −1.0 to 27.0); the mean PVP was 13.7 mmHg (6.3; 0.0 to 33.0); offset (bias) of PVP > CVP was 3.7 mmHg with SD 2.6. The 95% confidence intervals (CI) for the bias were 3.2 to 4.1 mmHg. In the Bland-Altman analysis, lower and upper limits of agreement (LOA; CI in parentheses) were −1.5 (−2.3 to −0.7) and 8.8 (8.1 to 9.6) mmHg. Eight of 96 points were outside the limits of agreement. The correlation of PVP on CVP was r = 0.92,P < 0.0001. For a subset of ten patients (20 simultaneous recordings) withiv atheters proximal to the hand, limits of agreement were better — offset: 3.8 mmHg (± 1.4); lower LOA: 1.2 mmHg (0.25 to 2.1); upper LOA: 6.6 mmHg (5.7 to 7.5).ConclusionPeripheral venous pressure measured from aniv catheter in the hand predicts CVP poorly in pediatric patients.RésuméObjectifLa tension veineuse périphérique (TVP) est une façon pratique de remplacer la tension veineuse centrale (TVC) comme indicateur de la réplétion volémique, à moindre risque et à meilleur coût. l’objectif de cette étude était de déterminer si la TVP est un bon reflet de la TVC chez les enfants.MéthodeAprès l’approbation du comité d’éthique et l’obtention du consentement, 30 sujets de 0 à 12 ans chez qui un cathéter veineux central était indiqué ont été recrutés de façon prospective dans un hôpital universitaire de soins tertiaires. On a mesuré la TVP et la TVC simultanément en position dorsale à 96 reprises. On a réalisé des analyses de corrélation et de Bland-Altman pour les mesures télé-expiratoires.RésultatsLa TVC moyenne (ET; extrêmes) était de 10,0 mmHg (6,0; −1,0 à 27,0); la TVP était de 13,7 mmHg (6,3; 0,0 à 33,0); la TVP était de 3,7 mmHg (ET 2,6) supérieure à la TVC. Les intervalles de confiance à 95% (IC) pour cet écart (biais) étaient de 3,2 à 4,1 mmHg. Selon l’analyse Bland-Altman, les limites de concordance inférieure et supérieure (LDC; CI entre parenthèses) étaient de −1,5 (−2,3 à −0,7) et 8,8 (8,1 à 9,6) mmHg. Huit des 96 points étaient à l’extérieur des limites de concordance. La corrélation entre PVP et TVC était r = 0,92, P < 0,0001. Dans un sous-groupe de dix patients (20 mesures pairées) avec des cathéters iv plus proximaux que la main, la concordance était meilleure — biais: 3,8 mmHg (± 1,4); LDC inférieure: 1,2 mmHg (0,25 à 2,1); supérieure: 6,6 mmHg (5,7 à 7,5).ConclusionLa tension veineuse périphérique mesurée à partir d’un cathéter installé sur la main ne reflète pas bien la TVC chez les enfants.

Lumbar vein malposition of inferior vena cava catheters

The authors report on a 1 year old who suffered permanent paralysis as a complication of a malpositioned inferior vena cava catheter. A simple protocol to avoid such neurological complications is presented.

Aluminum Exposure from Parenteral Nutrition: Early Bile Canaliculus Changes of the Hepatocyte

Background: Neonates on long-term parenteral nutrition (PN) may develop parenteral nutrition-associated liver disease (PNALD). Aluminum (Al) is a known contaminant of infant PN, and we hypothesize that it substantially contributes to PNALD. In this study, we aim to assess the impact of Al on hepatocytes in a piglet model. Methods: We conducted a randomized control trial using a Yucatan piglet PN model. Piglets, aged 3–6 days, were placed into two groups. The high Al group (n = 8) received PN with 63 µg/kg/day of Al, while the low Al group (n = 7) received PN with 24 µg/kg/day of Al. Serum samples for total bile acids (TBA) were collected over two weeks, and liver tissue was obtained at the end of the experiment. Bile canaliculus morphometry were studied by transmission electron microscopy (TEM) and ImageJ software analysis. Results: The canalicular space was smaller and the microvilli were shorter in the high Al group than in the low Al group. There was no difference in the TBA between the groups. Conclusions: Al causes structural changes in the hepatocytes despite unaltered serum bile acids. High Al in PN is associated with short microvilli, which could decrease the functional excretion area of the hepatocytes and impair bile flow.