Current Practice Regarding the Enteral Feeding of High-Risk Newborns With Umbilical Catheters In Situ
* Department of Pediatrics
Center for Pediatric Research, Children’s Hospital of The King’s Daughters and Eastern Virginia Medical School, Norfolk, Virginia
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ABSTRACT |
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 TOP ABSTRACT METHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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Objective. Textbooks recognize the controversy of concomitant enteral nutrition (EN) during umbilical catheter usage in high-risk newborns, but support for the practice varies. There is only one clinical trial examining these practices in a small but randomized, controlled trial of enterally fed newborns with umbilical arterial catheters (UACs) in situ, and that trial did not demonstrate any adverse consequences. We speculate that concomitant EN with umbilical catheter usage is more common than some textbooks suggest—practiced by at least 20% of all US neonatal intensive care units (NICUs). The objective of this study is to determine the prevalence of NICUs where high-risk newborns with UAC or umbilical venous catheter (UVC) placement receive concomitant EN.
Methods. Medical Directors listed in the American Academy of Pediatrics United States Neonatologist and Perinatologist Directory were surveyed by mail. On return of surveys, responses to multiple choice questions were recorded by electronic scanning and validated by manually conducted quality control checks. NICU identities were recorded by code to maintain anonymity.
Results. Following 2 requests for survey participation, 70% (549/785) of surveys were returned. Respectively, 82% and 62% of NICUs with and without training programs were represented. On average, surveyed medical directors had practiced neonatal medicine 18.1 ± 0.3 years. Of surveyed NICUs, 99% reported placement of UVCs and UACs. Of the 92% believing that it is safe to provide trophic EN to newborns with UVCs in place, 51% practiced this some of the time, and 37% practiced it most of the time. By comparison, it was reported that newborns with UACs in place receive trophic EN most of the time (30%), some of the time (49%), or none of the time (22%). Of the 80% believing that it is safe to provide more complete EN to newborns with UVCs in place, 44% practiced this some of the time, and 24% practiced it most of the time. For newborns with UACs in place, more complete EN was provided most of the time (15%), some of the time (36%), or none of the time (49%).
Conclusions. Concurrent UVC and UAC usage with EN is more commonly practiced than suggested in textbooks or published articles. The relative risk-benefit profiles of these practices remain uncertain secondary to the limited number of controlled clinical observations and to the infrequent occurrence of adverse events. A prospective, multicenter, controlled trial would address the continued advisability of these unexpectedly common practices.
Key Words: enteral nutrition • umbilical venous catheter • umbilical arterial catheter • high-risk newborn
Abbreviations: EN, enteral nutrition • NEC, necrotizing enterocolitis • NICU, neonatal intensive care unit • UAC, umbilical arterial catheter • UVC, umbilical venous catheter
Cannulation of the umbilical vein was initially described in 1947 for the treatment of severe hyperbilirubinemia by exchange transfusion.1 By comparison, umbilical artery cannulation was described in 1959 to obtain samples for blood gas and pH analysis.2 In subsequent decades, increasing utilization of umbilical venous catheters (UVCs) and umbilical arterial catheters (UACs) has continued to evolve. Evolution has continued because placement of umbilical catheters in high-risk newborns facilitates both the monitoring of blood chemistries and the administration of fluid, drugs, nutrition, and blood. Despite development of both noninvasive technologies for monitoring blood chemistries and alternative modes of central venous access, the frequency of umbilical catheters has remained high with the increasing delivery of very low birth weight newborns.
Clinical practices regarding umbilical catheter usage have developed without clear consensus regarding concomitant enteral nutrition (EN). Historically, neonatologists questioned the safety of these practices because of the purported, individual risks of EN and umbilical catheter placements for necrotizing enterocolitis (NEC). More recently, prevailing opinion as reflected in textbooks has recognized the controversy of concomitant EN with umbilical catheter usage, but support for the practice has varied from nonpermissive3,4 to undecided5 or supportive.6,7 The only clinical trial addressing these practices is a recent, small but randomized, controlled trial of enterally fed newborns with UAC in situ. In this study, Davey et al8 did not demonstrate any adverse consequences, and it is our perception that utilization of this practice has increased over the past decade. In addition to lack of consensus about concomitant EN, indications for catheter placement, location, confirmation, and duration also lack reported consensus.
We hypothesized that at least 20% of all US neonatal intensive care units (NICUs) practice concomitant EN with UVC in situ and that fewer practice it with UAC in situ. To characterize the prevalence of umbilical catheter placement and concomitant EN, we surveyed US NICUs with a primary objective of quantifying concomitant EN occurring with umbilical catheter placement. A secondary objective became the identification of standards of practice regarding UVC placement and usage.
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METHODS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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To identify standards of practice regarding umbilical catheter usage and placement, a cross-sectional survey was chosen as the study design to expediently and inexpensively survey by mail the majority of all NICU medical directors in the United States and US territories. For the sample, medical directors were identified by their inclusion in the United States Neonatologist and Perinatologist Directory published by the American Academy of Pediatrics.9 To both promote compliance and express appreciation for participation, 1 dollar was included in the initial mailing sent to 785 medical directors. We also sought to examine differences between training facilities and non-training facilities regarding catheter usage and placement. Training programs were defined by the presence of a graduate pediatric training program. Two mailings were sent in an attempt to maximize participation.
To promote compliance and facilitate coding and analysis, the survey was limited to a total of 17 questions—most of which were closed-ended (Table 1). In planning the survey, we significantly underestimated the acceptance by US neonatologists of concomitant UAC usage and EN—thereby focusing most survey questions on UVC usage and placement. To minimize the risk of overlooking responses by the use of closed-ended questions, options for open-ended responses were available to participants. For the purpose of this survey, trophic enteral feedings were defined by infusion flow rates 
1 mL per hour. A pilot of the survey was circulated locally to develop an instrument with clarity and reliability.
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To maximize anonymity, a research assistant assigned numeric identifiers to returned surveys. Principal investigators were blinded to the location and identity of responding directors in the survey. Responses to closed-ended questions were electronically scanned and validated by manually conducted quality control checks. Responses to open-ended questions were recorded manually by a research assistant and categorized by the principal investigators. The survey protocol was exempted from review by the Institutional Review Board of Eastern Virginia Medical School.
For analysis, data were entered in a spreadsheet and analyzed both collectively and following stratification by the presence of a training program. Comparisons between responses from NICUs with and without training programs were analyzed using the 
2 test, Wilcoxon rank sum test for continuous non-normally distributed outcomes, and t test for continuous normally distributed outcomes.
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RESULTS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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Following the first mailing, 51% (398/785) of surveys were returned within 6 weeks. A second mailing increased total response rate to 70% (549/785). Of the 785 centers, 206 were identified as training programs. NICUs with training programs had an 82% response rate versus a 62% response rate from NICUs without training programs. Response rates were 71 ± 2% (mean ± standard error of the mean) among 49 states, Puerto Rico, and Washington, DC. Responding medical directors had an average of 18.1 ± 0.3 years (range: 3–40 years) NICU experience.
Of the responding directors, 99% reported placement of UVCs and UACs. The most frequently reported indications for UVC placement were emergency access (95%), exchange transfusions (90%), intravenous fluids (66%), total parenteral nutrition (64%), general venous access (56%), medications (48%), and central venous pressure monitoring (41%).
Most medical directors (99.8%) reported confirmation of correct UVC tip placement by radiography. Six percent evaluated catheter tip placement by ultrasound employing a combined approach with radiographic examination. Preferred UVC tip placements were at the junction of the inferior vena cava and right atrium (39%), 0 to 1 cm above the diaphragm (27%), 1 to 2 cm above the diaphragm (24%), at the level of the diaphragm (7%), 2 to 3 cm above the diaphragm (3%), and below the liver (1%).
Reported median duration of UVC placement was 6 days (95% confidence interval [5–7 days]) with a range of 0 to 28 days. Most directors (98%) reported that there were no protocols for changing UVCs to prevent infection in their NICUs. After initial placement of UVCs, 16% of directors reported having indications for changing UVCs. These indications included poor position, malfunction, occlusion, and replacement of single lumen catheters with double lumen catheters.
Directors were surveyed on the appropriateness of EN with concomitant UVC or UAC placement. Most (92%) believed that trophic EN (defined as 1 mL/hour) is safe with concomitant UVC placement. Moreover, 80% believed that more complete EN with concomitant UVC placement is also safe. Directors also reported the frequency with which trophic EN is practiced with concomitant UVC placement. Thirty-seven percent reported EN is practiced with concomitant UVC placement most of the time, 51% reported some of the time, and 12% reported EN is never practiced with concomitant UVC placement. Twenty-four percent of directors reported that more complete EN with concomitant UVC placement is practiced most of the time, 44% reported this practice some of the time, and 31% reported that more complete EN with concomitant UVC placement is never practiced. By comparison, it was reported that newborns with UACs in place receive trophic EN most of the time 30%, some of the time 49%, and none of the time 22%. Moreover, for newborns with UACs in place, more complete EN was provided most of the time 15%, some of the time 36%, and none of the time 49%. Directors that do not initiate either trophic or more complete EN while UVC or UAC is placed reported removal of either catheter a median of 12 hours (range: 0–24 hours) before starting EN.
Seventy-nine percent of directors who practiced UVC placement reported complications occurring with UVC placement. Table 2 denotes complications related to the use of UVCs. The most commonly reported adverse events were infection (70%), pericardial effusion (33%) cardiac arrhythmias (33%), thromboembolic events (26%), and NEC (18%).
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Data also were stratified based on presence or absence of a training program. Only 2 significant differences were noted among programs. Directors of NICUs sponsoring training programs indicated slightly more years of experience (mean 19.8 years vs 17.3 years, P < .001), and twice as many training directors reported association of UVC placement with portal vein thrombosis (16.1% vs 8.9%, P = .028).
Open-ended questions were included in the survey to minimize the risk of overlooking responses excluded by the closed-ended questions. However, open-ended responses were too few and varied to characterize them with confidence.
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DISCUSSION |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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This brief survey was designed to define the current standard of practice regarding umbilical catheter placement and concomitant EN in US NICUs. In addition, the survey evaluated perceptions regarding indications for, location of, and complications of UVC placement. The emphasis on UVC practice emerged from expectations that concomitant umbilical catheter placement and EN would heavily favor UVC usage. However, we significantly underestimated the acceptance of concomitant UAC usage and EN by US neonatologists. The survey was limited to 17 questions to maximize rate of response. As a cross-sectional survey of medical directors, the study was not designed to determine compliance with perceived standards or actual practice. Nor was it designed to determine rates of associated adverse events or possible causal relationships. The survey included the majority of identified US NICU medical directors from all regions of the United States and selection bias was deemed minimal. Overall response rate and response rates by state were nearly identical (70% vs 71 ± 2%). Although NICUs with training programs had a 20% greater response rate than other NICUs, the differences among most responses were negligible.
As reflected in the peer-reviewed literature,10,11 a main concern of umbilical catheter use is identification and prevention of associated complications. In this regard, complications may be separated into: 1) complications associated with the placement and position of the umbilical catheter; 2) complications associated with an indwelling umbilical catheter over time; and 3) provision of EN concomitantly with an umbilical catheter in place. Regarding the first group, a common complication of UVC placement is malposition of the catheter tip. Identified complications include, but are not limited to, cardiac perforation, cardiac arrhythmias, thrombotic endocarditis, hemorrhagic infarction of the lungs, hydrothorax, portal vein thrombosis, and hepatic necrosis. By the current survey, radiography is clearly the imaging study of choice for catheter placement. Greater than 90% of respondents employed plain films to document catheter tip placement. Six percent used ultrasound combined with radiography. Real-time ultrasound has been shown to reduce complications during insertion by avoiding both false passage into the portal sinus and advancement into the left atrium.12 However, because ultrasound is not always accessible or cost-effective, it has been recommended that UVC tips be placed at thoracic vertebrae 8 or 9 corresponding to the junction of the right atrium and inferior vena cava.13 By the current survey, only two fifths of the medical directors have adopted this recommendation. Although we did not probe medical directors about the ideal UAC placement in the present survey, others have considered this question, and there are 2 locations that UACs are typically placed. Mokrohisky and colleagues13 identified that 52% of NICUs report high placement (7th–8th thoracic vertebrae) of UACs while 48% report low (3rd–4th lumbar vertebrae).
The second group of complications relates to those attributed to indwelling umbilical catheters. In this regard, Symansky and Fox14 reported the complication rate of UVCs to be 2 times the complication the rate of UACs. They performed postmortem examinations on 18 of 21 infants that died during their study and found that 11 of 18 had thrombi in the umbilical vein, ductus venosus, or portal vein. By our survey, 25% of medical directors report thromboembolic events as perceived complications of UVCs. Although not addressed by our survey, hemorrhage and thromboembolic events are also documented complications of both high and low UAC placements.9,15
Among other complications associated with indwelling umbilical catheters, line sepsis continues to be well-documented. The prevalence of umbilical catheter-related sepsis ranges from 3% to 16%,16 and our survey reveals that 68% of the directors appreciates line sepsis as a significant complication of indwelling UVCs. Another leading cause of morbidity and mortality among neonates is NEC. Infants with NEC represent 1% to 5% of the NICU admissions, and the percentage of NEC increases with increasing prematurity.17 Although a causal relationship between UVC use and NEC has not been established, 18% of directors in our survey perceived NEC as a complication of UVCs.
The last group of complications—those associated with umbilical catheters and concomitant EN—is of particular interest to practicing neonatologists because of continued uncertainty about the pathogenesis of adverse events associated with prematurity. This is particularly relevant in the absence of evidence establishing the relationship between concomitant EN, umbilical catheter placement, and NEC or feeding problems. Davey and colleagues8 have completed 1 study of concomitant EN and UAC placement. Employing a prospective, randomized, placebo-controlled, clinical trial design that included 60 patients, they found no differences in feeding problems among treatment and control groups. Although not sufficiently powered to fully exclude possible contributing risk of concomitant EN and UAC placement to NEC, this trial provides the best evidence for lack of harm. To date, an equivalent study examining possible complications associated with enteral feeding and concomitant UVC placement has not been performed. Overall, it remains concerning that peer-reviewed literature provides limited support for a practice that at least 92% of US NICUs support but that one fifth of directors still believe is associated with NEC.
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CONCLUSIONS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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Controversy regarding the risks and benefits of concomitant EN and UVC or UAC usage continue. Contrary to our original hypothesis that 20% practice these approaches, our data suggests that the majority of US NICUs provide EN to newborns with umbilical catheters in place. At this time, there are no published recommendations endorsing this possibly harmful practice. The relative risk benefit profiles of these practices remain uncertain secondary to the limited number of controlled clinical observations and to the infrequent occurrence of adverse events. A prospective, multicenter, controlled trial would address the continued advisability of these unexpectedly common practices.
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FOOTNOTES |
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Received for publication May 15, 2002; Accepted Oct 15, 2002.
Address correspondence to David G. Oelberg, MD, Children’s Hospital of The King’s Daughters, Department of Pediatrics, 601 Children’s Lane, Norfolk, VA 23507. E-mail: doelberg{at}chkd.com
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PEDIATRICS (ISSN 1098-4275). ©2003 by the American Academy of Pediatrics
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