Simon J. Newell

Randomised controlled study of clinical outcome following trophic feeding

AIMS To determine the effect of trophic feeding on clinical outcome in ill preterm infants. METHODS A randomised, controlled, prospective study of 100 preterm infants, weighing less than 1750 g at birth and requiring ventilatory support and parenteral nutrition, was performed. Group TF (48 infants) received trophic feeding from day 3 (0.5–1 ml/h) along with parenteral nutrition until ventilatory support finished. Group C (52 infants) received parenteral nutrition alone. “Nutritive” milk feeding was then introduced to both groups. Clinical outcomes measured included total energy intake and growth over the first six postnatal weeks, sepsis incidence, liver function, milk tolerance, duration of respiratory support, duration of hospital stay and complication incidence. RESULTS Groups were well matched for birthweight, gestation and CRIB scores. Infants in group TF had significantly greater energy intake, mean difference 41.4 (95% confidence interval 9, 73.7) kcal/kg p=0.02; weight gain, 130 (CI 1, 250) g p = 0.02; head circumference gain, mean difference 0.7 (CI 0.1, 1.3) cm, p = 0.04; fewer episodes of culture confirmed sepsis, mean difference −0.7 (−1.3, −0.2) episodes, p = 0.04; less parenteral nutrition, mean difference −11.5 (CI −20, −3) days, p = 0.03; tolerated full milk feeds (165 ml/kg/day) earlier, mean difference −11.2 (CI −19, −3) days, p = 0.03; reduced requirement for supplemental oxygen, mean difference −22.4 (CI−41.5, −3.3) days, p = 0.02; and were discharged home earlier, mean difference −22.1 (CI −42.1, −2.2) days, p = 0.04. There was no significant difference in the relative risk of any complication. CONCLUSIONS Trophic feeding improves clinical outcome in ill preterm infants requiring parenteral nutrition. Key messages Timing of the introduction of milk feeds in sick low birthweight infants is controversial. Almost all infants with non-surgical illness can tolerate at least some milk as trophic feeds. Trophic feeding leads to improved energy intake, weight gain, milk tolerance, less sepsis and earlier hospital discharge. No increase in major complication rate is seen following trophic feeding.

Central Venous Catheter Tip in the Right Atrium: A Risk Factor for Neonatal Cardiac Tamponade

Fatal cardiac tamponade is a well recognised complication of the use of central venous catheters in neonatal patients. There is controversy over optimum catheter tip position to balance catheter performance against risk of adverse events. We report a series of five cases of tamponade occurring in one neonatal unit over a 4-year period, related to catheter tip placement in the right atrium. Right atrial catheter angulation, curvature or looping (CA) was present in all five cases on plain radiograph. It was infrequently seen in other patients over the same period. Review of the literature indicates that CA was present in 6 of the 11 previous cases where the presence or absence of CA can be determined. Where right atrial catheter tip placement is accepted, clinicians should be aware of this characteristic catheter configuration, which is a major risk factor for cardiac tamponade. We recommend that catheter tips should not be placed in the right atrium to avoid risk of tamponade.

ENTERAL FEEDING OF THE MICROPREMIE

Clinical practice demands knowledge of gastrointestinal ontogeny and the factors that affect our ability to use enteral feeding in the micropremie. The decisions regarding milk type (when and how it should be given) are considered in the light of current physiologic and clinical evidence. Special considerations apply in the micropremie who is also small for gestational age and NEC must be avoided. Trophic feeding now has an established role, allowing the infant to benefit from enteral feeds even when full nutritive milk feeding is not possible.

Using cognitive task analysis to facilitate the integration of decision support systems into the neonatal intensive care unit

OBJECTIVE New medical systems may be rejected by staff because they do not integrate with local practice. An expert system, FLORENCE, is being developed to help staff in a neonatal intensive care unit (NICU) make decisions about ventilator settings when treating babies with respiratory distress syndrome. For FLORENCE to succeed it must be clinically useful and acceptable to staff in the context of local work practices. The aim of this work was to identify those contextual factors that would affect FLORENCEs success. METHODS A cognitive task analysis (CTA) of the NICU was performed. First, work context analysis was used to identify how work is performed in the NICU. Second, the critical decision method (CDM) was used to analyse how staff make decisions about changing the ventilator settings. Third, naturalistic observation of staffs use of the ventilator was performed. RESULTS A. The work context analysis identified the NICUs hierarchical communication structure and the importance of numerous types of record in communication. B. It also identified important ergonomic and practical requirements for designing the displays and positioning the computer. C. The CDM interviews suggested instances where problems can arise if the data used by FLORENCE, which is automatically read, is not manually verified. D. Observation showed that most alarms cleared automatically. When FLORENCE raises an alarm, staff will normally be required to intervene and make a clinical judgement, even if the ventilator settings are not subsequently changed. CONCLUSIONS FLORENCE must not undermine the NICUs hierarchical communication channels (A). The re-design of working practices to incorporate FLORENCE, reinforced through its user interface, must ensure that expert help is called on when appropriate (A). The procedures adopted with FLORENCE should ensure that the data the advice is based upon is valid (C). For example, FLORENCE could prompt staff to manually verify the data before implementing any suggested changes. FLORENCEs audible alarm should be clearly distinguishable from other NICU alarms (D); new procedures should be established to ensure that FLORENCE alarms receive attention (D), and false alarms from FLORENCE should be minimised (B, D). FLORENCE should always provide the data and reasoning underpinning its advice (A, C, D). The methods used in the CTA identified several contextual issues that could affect FLORENCEs acceptance. These issues, which extend beyond FLORENCEs capability to suggest changes to the ventilator settings, are being addressed in the design of the user interface and plans for FLORENCEs subsequent deployment.

Gastric ontogeny: clinical implications

The delivery of a preterm infant offers a unique opportunity to look directly upon the process of ontogeny, while at the same time organ immaturity is the basis of the clinical problems which challenge neonatal medicine. In recent years our knowledge of foregut ontogeny has increased, together with an increased body of clinical experience, yet the nutritional management of the preterm infant remains a contentious area, with wide variations in clinical practice. The compelling evidence of the importance of early nutritional management on neurodevelopmental outcome now focuses the debate sharply. Closer knowledge of the development of functional maturity in the gut may allow more rapid and rational advances to be made. In this paper we discuss the embryology, the development of secretory and digestive function, and the maturation of gastro-oesophageal motor activity as a background to the clinical management of nutrition in the preterm infant.

Gastric secretory function in the developing human stomach

Little data exists regarding the activity of gastric parietal cells in the very immature infant. Therefore we have examined the developing human stomach for the presence and location of parietal cells, using both standard histological methods and antibodies to the H+/K+ ATPase (proton pump) and intrinsic factor, in 35 fetuses (ranging from 13-28 weeks) and in five infants (2-21 weeks). Parietal cell activity was noted in the body, antrum and pyloric regions in all the fetal specimens examined. However, this activity was much more limited in the infant specimens. We have noted that from the end of the first trimester parietal cells are present in a mature, functional form with the potential to secrete both gastric acid and intrinsic factor.

Gastrointestinal function and its ontogeny: how should we feed the preterm infant?

Knowledge of gastrointestinal ontogeny provides a rational basis for the use of enteral nutrition in the preterm infant. In all but the least mature infants, digestive and absorptive capacity is good. Immature motility commonly results in gastrointestinal problems, which include poor toleration of milk feeds, gastro-oesophageal reflux, and inadequate gastric emptying. Problems are exacerbated by poor fetal health and intra-uterine growth retardation. These considerations are important in the choice of method of nutrition. When parental nutrition is used, minimal enteral feeding has beneficial effects upon maturation of gut motility.

Placement of neonatal central venous catheter tips in the right atrium: a practice to be avoided?

Editor—Following the recent media interest in pericardial tamponade complicating the use of percutaneous central venous catheters in neonatal patients, we wish to alert readers to our experience. Our previous policy was to accept right atrial placement of percutaneous central venous catheter tips. This was in line with published recommendations1-3 and is still considered acceptable practice in some …

Premedication for neonatal intubation: current practice in Australia and the United Kingdom.

Editor—The paper by Bhutada et al 1 adds to the growing body of evidence that premedication for tracheal intubation in neonates both improves physiological stability and makes the procedure easier to perform. The results of the telephone survey of premedication use in UK neonatal units by Whyte et al 2helps to define current practice. In a similar study, we recently tried to define the routine use of …

EFFECTS OF TRANSFUSION IN ANEMIA OF PREMATURITY

The authors aimed to test the hypothesis that blood transfusions depress hematopoiesis in healthy infants with anemia of prematurity (AOP). They also set out to find markers that predict recovery from AOP. Thirty-nine premature babies underwent weekly and post-transfusion measurements of hemoglobin concentrations, reticulocyte counts (RCC), and erythropoietin levels (EPO). RCC and EPO dropped significantly 7 days after a blood transfusion but had normalized after 14 days. Elevated RCC or EPO levels were not predictive of an increase in hemoglobin. Postnatal HbFg/dL was higher in babies who had received transfusions. The authors conclude that blood transfusions depress erythropoiesis in infants with AOP and stimulate HbF synthesis but this effect is not sustained. Reticulocyte counts and erythropoietin levels are unhelpful in predicting recovery from AOP.