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A perspective on the paper by Patole and de Klerk1
Necrotising enterocolitis (NEC), an acquired gastrointestinal disease in neonatal intensive care unit survivors, affects one to three infants per 1000 live births and is associated with significant mortality and morbidity.2,3 Although it has not been proven, many believe that, in premature infants, a precursor to NEC is feeding intolerance, specifically, prefeed gastric residuals or bile stained aspirates.4–6 These associated intestinal signs of NEC may also reflect a delay in maturation of the neonate’s motor activity such that they lack complete interdigestive cycles during fasting. As no biological markers exist to diagnose NEC, clinical wisdom guides decision making related to its diagnoses and management. Furthermore, there is a paucity of research identifying feeding practices, except for breast milk feeds, that offer the greatest potential benefit against developing NEC. Moreover, hormonal, anatomical, and functional limitations of low birthweight infants, the additive effects of critical illness, and intrauterine environmental factors—for example, antenatal glucocorticoids—complicate feeding decisions in this population of infants. Consequently, there is great variability in feeding orders for low birthweight infants.
A standardised feeding regimen (SFR) is one strategy to address the challenges of feeding low birthweight infants. Establishing such an SFR would require synthesising the available evidence7 and communicating the clinical wisdom from the experts, thereby promoting a more systematic approach to feeding low birthweight infants. A systematic review and meta-analysis of observational studies reporting the incidence of NEC “before” and “after” implementation of SFR undertaken by Patole and de Klerk1 reported a pooled risk ratio of 0.13 (95% confidence interval 0.03 to 0.50). The reduced incidence of NEC after the introduction of SFRs was attributed to minimisation of variations in enteral feeding practices.1 However, it is unclear what degree of variation in practice will significantly contribute to the incidence of NEC. Alternatively, what measure of reduction in variation in practice resulting from the implementation of SFRs will significantly contribute to a decrease in the incidence of NEC?
In order for an SFR to attain the goal of preventing or minimising NEC, compliance or adherence to the regimen is imperative. The issue of compliance with the SFR may also contribute to the significant heterogeneity (p<0.001) noted between studies included in the systematic review by Patole and de Klerk.1 One must consider ethical conflict when addressing the issue of non-compliance. Uncertainty is reduced in SFRs through the prudent use of evidence from rigorous trials or, in the absence of such trials, expert clinical opinion. The intent is to minimise the art of medicine and promote the use of clinical science.8 The validity of the SFR will be limited if the evidence on which it is based is weak.9 In addition, SFRs are not intended to be prescriptive, and their use in clinical practice will ultimately require the practitioner’s judgment. The consensus of experts, which has been the crux of the development of SFRs, may eliminate idiosyncratic judgments of single clinicians; however, it introduces value judgments—for example, choice made on the basis of safety or effectiveness—about what ought to be done for a condition.10 Understanding these ethical conflicts or dilemmas will help to facilitate implementation or revision of guidelines and increase the potential benefit to low birthweight infants. Future studies evaluating SFRs need to have a qualitative component that identifies and defines ethical issues, explains ethical judgments or behaviours, and analyses or appraises clinical decision making.
Patole and de Klerk1 propose that clinical variation in practice determines risk of NEC. Although not explicitly stated, one can infer that this refers to variability in physician orders. However, nursing management of tube feeding is also inconsistent and varies from nurse to nurse.11 Each nurse uses their individual expertise to resolve problems related to regurgitation, abdominal distension, and residuals.12 Hodges and Vincent13 have shown variability in the practice of withdrawing feeding and management of feeding residuals. As the success of any nutritional approach depends on neonatal nurses, who spend a significant amount of time feeding, and assessing infants before, during, and after feeds,11 a better understanding of nursing practice related to tube feeding is required. This understanding will facilitate a unified systematic approach to nursing management of tube feeds based on the current state of scientific knowledge.
Patole and de Klerk1 attribute the reduced incidence of NEC after the introduction of an SFR to an increased awareness leading to early detection and management of signs of “feeding intolerance”. However, there is no consensus in the literature with regard to the operational definition of feeding intolerance. In the scientific literature, prefeed gastric residual volumes, colour of gastric aspirates, abdominal distension, spitting up, presence of blood in stool, and apnoea and bradycardia are signs listed for feeding intolerance.6,14–16 Researchers have tried to define feeding intolerance by quantifying volume of prefeeding gastric residuals considered to be significant; however, the volume considered significant varies across studies. The threshold of what is considered to be a significant volume of gastric residual appears to be increasing.17 The chances that clinicians will adopt SFRs decreases with an increase in uncertainty of the validity of the science behind them. A standardised approach to identifying feeding intolerance and predicting NEC will facilitate compliance with SFRs, as well as facilitate a more meaningful interpretation of studies that examine the relation between diet and gastrointestinal diseases such as NEC. One potential strategy is the development of decision rules that have been assessed for reliability and validity.
The process by which SFRs are shared and eventually adopted is a social process which influences the clinician’s knowledge, attitudes, and behaviour.18,19 Consequently it is not surprising that Patole and de Klerk1 note that it is the process rather than the specific constituents that lead to improved outcomes. A Cochrane systematic review on guidelines in professions allied to medicine—for example, nursing, midwifery, and health visiting—identified 18 studies that provide evidence that guideline driven care can be effective in changing the process of care.20
In conclusion, an SFR offers hope for reducing the risk of NEC by decreasing variability in practice. SFRs should address variability in both medical and nursing practice. Implementation strategies that comprise processes aimed to improve the clinician’s compliance with the recommendations will determine the extent to which they are useful. It is imperative, however, that clinicians understand the values driving research, outcomes, and management issues. If clinicians lack this understanding, then ethical conflict or dilemmas could ensue which may impede the adoption of the SFR. In addition, SFRs may not be appropriate for all low birthweight infants, hence, clinicians need to exercise judgment otherwise they may compromise the infant’s care. Future studies need to measure the relative effectiveness of the SFR. Emphasis on effectiveness will allow the researcher to evaluate the utility of the SFR in practice, process of care, quality of care, and patient/parent satisfaction.21
A perspective on the paper by Patole and de Klerk1
Competing interests: none declared
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