Joshua T. Attridge

Emerging trends in acquired neonatal intestinal disease: is it time to abandon Bell's criteria?

In the last decade, it has become increasingly clear that necrotizing enterocolitis (NEC) is neither a uniform nor a well-defined disease entity. There are many factors that are forcing this unwelcome realization upon the neonatal and pediatric surgery communities. In the course of this manuscript we will review the history and the physical findings of the disparate etiologies of acquired neonatal intestinal diseases (ANIDs), some which do lead to the common final pathology of NEC and some which do not. New guidelines for distinguishing between ANIDs will also be suggested.

Administration of rescue surfactant by laryngeal mask airway: lessons from a pilot trial.

OBJECTIVES To determine if surfactant can be effectively administered to larger preterm babies by laryngeal mask airway (LMA), reducing the need for supplemental oxygen. STUDY DESIGN Enrollment criteria: birth weight > 1200 g, < 72 hours old, treated with nasal continuous positive airway pressure (nCPAP) for respiratory distress syndrome, with fraction of inspired oxygen (Fio2) requirement between 0.30 and 0.60. Subjects were randomized either to receive 3 mL/kg calfactant by LMA (experimental) followed by LMA removal back to CPAP, or continued on nCPAP (control). After intervention, both groups remained on nCPAP with Fio2 adjusted to maintain O2 saturations at 88 to 95%. RESULTS A total of 26 patients (13 per group) were randomized, and 24 completed the study (11 experimental, 13 control). Groups were similar with respect to gender, mode of delivery, estimated gestational age, birth weight, and oxygen and pressure requirements at enrollment. Infants enrolled in the treatment group had an abrupt and sustained decrease in oxygen requirement after LMA surfactant therapy. CONCLUSION This pilot study demonstrates that surfactant can be delivered by LMA, which leads to a significant decrease in supplemental oxygen requirement. Larger controlled trials in low-resource settings may show this technique to be valuable in clinical situations where direct laryngoscopy and intubation are difficult or where resources for mechanical ventilation are limited.

Understanding Clinical Literature Relevant to Spontaneous Intestinal Perforations

Spontaneous intestinal perforation (SIP) has emerged as a disease of extremely low-birth-weight (ELBW) infants over the last two decades. Several risk factors have been associated with this disease including early postnatal steroids (EPS; use within the first week of life), early use of indomethacin (EUI; use within the first 3 postnatal days), and the synergistic combination of the two. These two risk factors are thought to play a causal role in the etiology of SIP through their effects on ileal trophism and motility. Two infectious agents ( Candida and Staphylococcus epidermidis) are commonly grown from peritoneal cultures of patients with SIP. It is less clear whether these infections play a causal role or if they represent comorbidities of perforation. Chorioamnionitis is thought to be a risk factor for SIP, as is the stress and elevated cortisol that accompanies it. Recent analyses suggest that antenatal indomethacin may also be a risk factor for SIP, particularly when given close to birth. These latter variables are more challenging to rank in importance compared with EPS and EUI, which have been repeatedly associated with SIP in both retrospective cohorts and randomized controlled trials. Because neonatal care of the ELBW infant is commonly standardized, the habitual combination of any of these risk factors potentially amplifies the risk of SIP. Many of these factors are medicines, thus SIP risk is exacerbated by select forms of polypharmacy. Our challenge lies in understanding how these drug interactions lead to harm.

Catecholamine-resistant hypotension and myocardial performance following patent ductus arteriosus ligation

Objective:We performed a multicenter study of preterm infants, who were about to undergo patent ductus arteriosus ligation, to determine whether echocardiographic indices of impaired myocardial performance were associated with subsequent development of catecholamine-resistant hypotension following ligation.Study Design:A standardized treatment approach for hypotension was followed at each center. Infants were considered to have catecholamine-resistant hypotension if their dopamine infusion was >15 μg kg–1min–1. Echocardiograms and cortisol measurements were obtained between 6 and 14 h after the ligation (prior to the presence of catecholamine-resistant hypotension).Result:Forty-five infants were enrolled, 10 received catecholamines (6 were catecholamine-responsive and 4 developed catecholamine-resistant hypotension). Catecholamine-resistant hypotension was not associated with decreased preload, shortening fraction or ventricular output. Infants with catecholamine-resistant hypotension had significantly lower levels of systemic vascular resistance and postoperative cortisol concentration.Conclusion:We speculate that low cortisol levels and impaired vascular tone may have a more important role than impaired cardiac performance in post-ligation catecholamine-resistant hypotension.

Potential confounder of NEC clinical trials

With great interest we read the article ‘Surfactants: past, present and future’ by HL Halliday. This article describes very well the unique success story of this wonderful substance that has not yet been finished. We were surprised to read about ‘surfactant administration in spontaneously breathing infants using a fine gastric tube’ as a single report at a meeting. In our German literature, this method has been more extensively reported. At our center, we developed and introduced this method for the first time. This method combines the positive effects of nCPAP and surfactant. The underlying idea is that inspiring surfactant is more physiologically appropriate than receiving it by positive pressure inflations as with the INSURE procedure. We reported the results in 2003 at the annual meeting of the GNPI (Gesellschaft für Neonatologie und Pädiatrische IntensivmedizinFSociety for Neonatology and Pediatric Intensive Care) in Cologne. This method was a topic of discussion at the annual meetings of the GNPI in the following years too. Therefore, we performed a pilot study in infants with a gestational age below 27 0=7 weeks. In this study, we showed the feasibility and an improvement of outcomes of the study group compared with a historical control group. The need for mechanical ventilation because of RDS was reduced from 77% in the historical control group to 48% in the study group. Mortality decreased from 35 to 12% and the rate of severe IVH in survivors from 32 to 5%. These results, combined with subsequent experiences, were published this year. The data confirmed the results of the original feasibility study. Our ongoing randomized controlled trials utilizing this technique are registered (AMV trial ISRCTN 05025922, NINSAPP trial ISRCTN 64011614), but the results are not yet available. A Kribs Department of Neonatology, Childrens’ Hospital University of Cologne, Children’s Hospital, Cologne, Germany E-mail: angela.kribs@uk-koeln.de

Reply to Dr Bell

It is with deep respect that we write this response to Dr Bell1 who has inspired generations of physicians to do research on acquired neonatal intestinal diseases, most notably NEC. We are also pleased to read his agreement that spontaneous intestinal perforation (SIP) and necrotizing enterocolitis (NEC) are distinct and separate disease entities. We hope that this editorial exchange will encourage others to consider how best to approach these disparate diseases and the populations they affect.

Reply to Drs Skerritt, Modi and Clarke

We greatly appreciate the letter from Drs Skerritt, Modi and Clarke, because the most important goal of our review1 was to stimulate dialogue across disciplines. It is obvious that two pediatric surgeons and a neonatologist did exactly that in drafting their letter. We are also gratified to learn that our arguments favoring the necessity of an alternative to Bells staging was well received. Hopefully this exchange is the beginning of a cordial and constructive debate that will reverberate throughout the neonatal and pediatric surgery communities over the next couple of years.