Ultrasound-Guided Umbilical Catheter Insertion in Neonates

SE Fleming and JH Kim Division of Neonatology, UCSD Medical Center, San Diego, CA, USA

Introduction Objective: Umbilical catheter placement is a routine neonatal emergency Inserting umbilical venous (UVC) and umbilical arterial (UAC) procedure that has large variability in technical methods. Commonly catheters is a routine urgent procedure in sick preterm and term used methods are unable to accurately estimate insertion lengths, and neonates. Two of the most common methods used to guide catheter X-rays cannot always identify malpositioned catheters. In clinical practice, insertion length are the shoulder–umbilicus length graph1 and the placement of umbilical lines takes time away from nursing during a a regression equation based on birth weight (BW).2 In these critical transition period. Ultrasound is a safe and commonly used tool in methods, catheters are inserted and advanced blindly to the the nursery for clinical management of sick neonates and has been shown predetermined length from the umbilicus. Both anterior-posterior to readily identify central catheter tip position. In this study, we sought to and lateral radiographs are taken after placement of the catheters determine a more time-efficient and accurate means of umbilical catheter to check the adequacy of catheter positioning. Many times, the placement using bedside ultrasound. catheters are not placed at the optimal position, thus necessitating Study Design: This is a prospective, randomized, pilot trial of infants them to be repositioned and X-rays repeated. This involves of any age or weight admitted to the neonatal intensive care unit who movement of often critically ill infants, further time away required umbilical catheter placement. Infants were excluded if they had from optimal nursing care and additional radiation exposure. congenital heart disease, abdominal wall defects or had a single umbilical Therefore, some studies strongly suggest that ultrasound with artery. Catheters were placed using either the conventional method, with direct visualization of the inserted catheter should be considered blinded evaluation of the catheters using ultrasound, or with ultrasound the gold standard to confirm correct catheter placement.3–5 guidance, with input pertaining to catheter tip location. The number of Several studies have questioned the current methods used for X-rays required to confirm proper positioning, completion time points estimating umbilical catheter insertion length. Lopriore et al.6 throughout the procedure and manipulations of the lines were recorded questioned 101 pediatric professionals from 6 centers in the for both groups. Netherlands and found that the method used by the participants to Result: Ultrasound use decreased the time of line placement with measure the shoulder–umbilicus length was highly inconsistent, an average saving of 64 min, as well as decreased the number of with only 14% using the described measurement. BW-based manipulations required and X-rays taken to place the catheters. methods that are widely used in the United States do not predict 7 The average X-ray time from request to viewing per X-ray was 40 min catheter placement as accurately in smaller preterm infants. 8 for all subjects. A study by Jeng et al. compared four methods (namely BW, suprasternal notch to pubic symphysis length, total body Conclusion: Ultrasound-guided umbilical catheter placement is a faster length and shoulder–umbilicus length) for UAC insertional method to place catheters requiring fewer manipulations and X-rays length in 120 neonates, and found 90% accuracy in the BW when compared with conventional catheter placement. and total body length groups and 70% accuracy in the suprasternal Journal of Perinatology (2011) 31, 344–349; doi:10.1038/jp.2010.128; notch to pubic symphysis length and shoulder–umbilicus published online 10 February 2011 length groups. Keywords: indwelling catheters; ultrasonography; umbilical cord; The most common method used to confirm the ideal UVC umbilical vessels position is anteroposterior chest radiography, although other tools such as lateral chest radiography,9 venous pressure monitoring,10,11 ultrasound5,12–14 and electrocardiogram guidance15,16 have also been suggested. Some studies have questioned the ability of 3,17 Correspondence: Dr JH Kim, Division of Neonatology, Department of Pediatrics, 200 West standard radiography to evaluate umbilical catheters accurately. Arbor Drive MPF 1-140, San Diego, CA 92103-8774, USA. They have found very low sensitivity and marginal specificity E-mail: [email protected] Received 8 May 2010; revised 11 August 2010; accepted 16 August 2010; published online 10 to detect misplaced lines. In addition, individual practitioners February 2011 use varying methods to obtain the optimal position, including Ultrasound-guided umbilical catheter insertion in neonates SE Fleming and JH Kim 345 deliberate higher placement with subsequent manipulation to a by scanning the mid-chest in the sagittal plane to locate the proper position.18 catheter tip position, and by scanning for the venous catheter In this study, we set out to find a more efficient and accurate in the sagittal plane on the anterior abdominal wall on the right method for determining optimal umbilical catheter position using mid-abdomen using the liver as an ultrasonic window. The bedside ultrasound. The current method of radiography for catheter injection of a small volume of sterile saline could be used to tip length confirmation is time consuming, exposes the newborn confirm the location of the catheter tip as the turbulence generated infant to radiation and involves physical movement of a sick can be seen with the injection. Care was taken to ensure infant. Bedside ultrasound offers the possibility of direct adequate oxygenation and temperature maintenance for the visualization of the catheter and the vessels both during the neonate during this procedure. insertion period and after final positioning. In the standard arm, the insertion of the catheter(s) proceeded according to standard methods used in our unit for the placement of umbilical catheters. This involved sterilization of the Methods umbilical cord stump, sterile draping of the infant’s abdomen, This was a prospective randomized study of any infant admitted to identification of umbilical vessels, dilation of vessels using metal the level III NICU (neonatal intensive care unit) at a single forceps and gentle insertion of either single or double lumen academic medical center that required UVC and/or UAC placement. catheters. After suturing the catheter(s), the position of the The period of recruitment was between 1 May 2008 and 30 April catheter(s) was evaluated by ultrasound, blinded to the placing 2009. The Institutional Review Board approved this study, and practitioner who would order an X-ray as per routine. This informed consent was obtained from the parents before enrollment. ultrasound exam was recorded for comparison. In the ultrasound- Block randomization was performed by card assignment in blocks guided arm, catheters were placed by the clinical team, with the of six and placed in sealed numbered envelopes. Operators were ultrasound operator by the bedside who evaluated using ultrasound not blinded to the randomization, but in the standard arm, they under sterile field immediately after initial catheter insertion. were blinded to ultrasound information. Depending on the images, catheter manipulations were suggested Enrolled infants were those admitted to the UCSD (University of to the practitioner for suboptimal catheter positioning and viewed California San Diego) Infant Special Care Center and requiring in real time until a suitable position was obtained. Once place- umbilical lines as per current critical care practices. Newborns ment was deemed optimal, the catheter(s) was secured and X-rays with congenital anomalies involving the abdominal wall or intra- were taken. In both groups, catheters unable to be positioned abdominal compartment, single umbilical artery or known congenital correctly were removed. The clinical team made the final decision on heart disease including the right aortic arch were excluded. catheter tip position using the X-ray, regardless of which arm the Umbilical catheters were placed by neonatal fellows, neonatal infant was enrolled in as this was considered the standard of care. nurse practitioners (NNPs) and pediatric house staff. The length of The insertion length was recorded as per current practice by catheter insertion was determined independently by the placing the nursing staff. Both anterior-posterior and lateral radiographs practitioner with the goal of optimal placement at the inferior vena were taken to confirm catheter placement and tip location; the cava–right atrial junction for the UVC and at the T7 to T9 lateral X-ray was included to optimally demonstrate the anatomic segment for the UAC. The decision regarding which of the various paths of both lines. The ultrasound findings were compared with common methods of determining the length should be used radiographs for catheter placement. The patient’s weight was (namely calculation, shoulder–umbilicus, etc.) was left to the recorded at the time of catheter placement. practitioner and the method used recorded. Manipulation was The primary outcome measure was total time of catheter defined as any deliberate movement of the position of the umbilical placement. All major interval time points were recorded. This catheter by the operator. included time at suturing of the line(s), requesting X-ray, X-ray The insertion of the catheter(s) took place under sterile taken and X-ray read by the practitioner. The ultrasound operator techniques as per routine practice, except that the upper right recorded time from the start of the procedure to completion corner of the sterile field was reflected upward and taped to the using a stopwatch. The start time for the procedure was defined overbed warmer. Ultrasound-guided placement was performed by as the time of placement of the sterile draping, whereas the either a neonatologist (JHK) experienced in dynamic (real-time) completion time was defined as the time when the nursing staff ultrasound localization of umbilical catheter tip location or a were advised to use the line. neonatal fellow (SEF) trained by JHK. The ultrasound operator The important secondary outcomes recorded were the number placed an ultrasound probe (13 MHz linear probe, Vivid i, General of X-rays taken, manipulations of the umbilical catheters, catheter Electric Healthcare) over the mid-chest to identify the inferior vena movement with leg position and infant temperature. Two views cava–right atrial junction and the T7 to T9 segment of the on X-ray counted as two X-rays. All major outcomes were compared descending aorta. The scans were performed for aortic catheters using Mann–Whitney’s U for nonnormally distributed data.

Journal of Perinatology Ultrasound-guided umbilical catheter insertion in neonates SE Fleming and JH Kim 346

All tests were performed two sided, with P<0.05 indicating (P ¼ 0.002) with the use of ultrasound guidance. The number of statistical significance. UAC manipulations between groups was not significantly different. The number of X-rays per patient was reduced from 4.1 to 2.3 Results using bedside ultrasound at the time of line placement A total of 31 infants were enrolled in the study, 16 in the (P ¼ 0.003) (Table 2). A total of 10 lines were removed in the standard placement group and 15 in the ultrasound-guided group. ultrasound (5 arterial and 5 venous) and standard (2 arterial The mean BWs were 1728±1133 g and 1312±917 g for the and 8 venous) groups because of unsuccessful attempts. Infant temperature was stable before and after the procedure for both ultrasound and standard groups, respectively (P ¼ 0.155). The groups (Table 2). mean gestational ages were 31 þ 1 weeks and 30 þ 2 weeks for Among infants with successful placement of both UAC and UVC the ultrasound and standard groups, respectively (P ¼ 0.452) (Table 1). Figure 1 shows the representative ultrasound image and (65% of the infants enrolled), the number of X-rays per patient radiographs obtained. Corresponding X-ray and ultrasound images was 4.3 for the standard group and 2.1 for the ultrasound group for standard placed catheters show the ease of identification of (P ¼ 0.01). The time necessary for placement was 142 min in line position close to the inferior vena cava–right atrial junction the standard group and 74 min in the ultrasound group using ultrasound (Figure 2). (P ¼ 0.004), and manipulations of the UVC were reduced from Real-time use of bedside ultrasound decreased the total time 2.6 to 1.3 for these groups, respectively. UAC manipulations were of line placement by 46% (P<0.001) that represented a saving not significantly different. All lines placed by ultrasound were of more than an hour in procedure time, from 139 to 75 min not altered after X-ray confirmation. (Table 2). The average time to obtain and read each set of Additional evaluation was undertaken to account for the level of radiographs was 40 min and did not differ between groups. training of the practitioner placing the lines. The average time for The number of UVC manipulations decreased from 2.8 to 1.6 all line placements was 142 min for new neonatal fellows, 85 min for second- and third-year fellows and 109 min for NNPs. The procedure took, on average, an additional 21 min if the pediatric Table 1 Baseline characteristics of the 31 infants enrolled for standard or house staff were involved (half of the lines placed in this study) ultrasound-guided placement of umbilical catheters compared with all practitioners. A total of 4 of 15 ultrasound and 5 of 16 standard procedures were accompanied by either a new Ultrasound-guided Standard P-value neonatal fellow or a first- to third-year pediatric resident. placement placement n 15 16 Gestational age 31+4±4+1 30+2±5+2 0.452 Discussion (weeks+days) Umbilical line placement is a routine procedure most often Birth weight in 1728±1133 (710–4760) 1312±917 (460–3668) 0.155 performed in the first hours of life for many infants admitted to grams, (range) the NICU. The sterile nature of the procedure requires that the Mean±s.d. infant be under drapes and not be easily visible to the care team

Figure 1 (a) Real-time ultrasound image shows both umbilical catheters reﬂecting (b) what would be seen on a lateral X-ray.

Journal of Perinatology Ultrasound-guided umbilical catheter insertion in neonates SE Fleming and JH Kim 347

Figure 2 Corresponding chest X-rays and ultrasound images demonstrate the relationship of a (a) low, (b) high and ﬁnally (c) acceptably placed UVC. The IVC–RA junction (indicated by *) is easily demarcated by ultrasound. An angled UVC in the liver (L) casts an easily recognizable shadow (arrow in panel a), whereas a horizontal catheter is seen directly (marked by ‘ þ ’ symbols). ‘H’ indicates the heart. IVC–RA, inferior vena cava–right atrial junction; UVC, umbilical venous catheter.

(unless clear drapes are used) during the critical transitional Table 2 Results of umbilical catheter placement using ultrasound guidance period after birth. Umbilical catheter placement involves multiple compared with standard placement in 31 neonates components, including preparation of the equipment and the Ultrasound Standard P-value infant, the actual catheter placement and evaluation of catheter group group position. The full time of this process can lead to significant Mean time to final placement in minutes 75±25 139±49 <0.001 time without optimal bedside visual monitoring and nursing at X-rays taken 2.3±0.6 4.1±1.4 0.003 a time when infants are often critically unwell. Manipulations of UAC 1.64±0.81 1.87±0.83 0.447 In this study, we found that bedside ultrasound was beneficial Manipulations of UVC 1.6±0.74 2.8±1.01 0.002 both in reducing total procedural time and overall physical burden. Infant temperature before procedure 97.7±0.7 98.6±1.47 0.105 We found a large difference in the time required to determine Infant temperature after procedure 97.8±1.5 98.4±0.7 0.270 acceptable line placement between the ultrasound and the standard Abbreviations: UAC, umbilical arterial catheter; UVC, umbilical venous catheter. placement groups. Clinical care could have resumed on average Mean±s.d. 64 min earlier in the ultrasound arm for any lines placed. A shorter

Journal of Perinatology Ultrasound-guided umbilical catheter insertion in neonates SE Fleming and JH Kim 348 time was noted even when the lines were unable to be placed. that venous catheters moved with infant movement, especially Malpositioned lines that could never be placed correctly were when the neonate’s legs and abdomen were flexed. In this study, recognized 57 min earlier in the ultrasound group, thus resulting we found that full leg extension to knee/hip flexion could lead to in large total time saved. further UVC migration into the heart in all infants studied with We chose to record a detailed or ‘true’ record of the time a mean migration of 0.54 cm (peak migration of 1.8 cm), a necessary for line placement. No previous literature that measured distance that becomes very relevant in smaller preterm infants catheter placement in this detailed manner was found. There is and in inadvertently deeper UVC placements. a significant difference between the full procedural time, from This study was conducted at an academic medical center where draping to initiation of infusion of the lines versus just the line lines were placed primarily by neonatal fellows and NNPs who placement time. This difference is explained by the time required worked with pediatric house staff to train them on line placement. for requesting the X-ray, alerting the diagnostic imaging Although the procedure may take longer because of the training of technician, taking the films, loading them into a digital system house staff, the distribution of catheter placements supervised and then allowing the provider time to view and interpret the film. by the house staff did not differ across groups. At other centers, Although our data are not necessarily reflective of the MD (Doctor the NNP or MD may place the line and return to other duties while of Medicine)/NNP time, our detailed record more accurately reflects the bedside nurse waits for the X-ray to become available. The lines the clinical impact on the infant and the nursing staff. are then adjusted as required, with the infant still under sterile We decided to evaluate all umbilical catheter placements with drapes. The total time from sterile preparation to ultimate removal radiography even when ultrasound was used. We chose this of the drapes may not be all that different between lines placed because it is the current standard of care for catheter placement, with house staff and those that are not. and we wanted to compare the accuracy of ultrasound placement Accessibility to the use of ultrasound is increasing in settings with this standard. Had we accepted ultrasound as the primary outside traditional areas, such as cardiology or diagnostic imaging. method of evaluating placement, our study would suggest that even Published data support the use of ultrasound by acute care faster overall procedural times could be achieved. The time to professionals not traditionally trained in the ultrasound technique achieve final placement without a radiograph was 33 min for in the emergency medicine, anesthesia and adult and pediatric patients in the ultrasound group. Each cycle of radiograph critical care literature.23–28 Most labor and delivery, as well as evaluation required an average of 40 min after line manipulation. emergency departments routinely use portable ultrasound devices. The use of ultrasound could significantly reduce the time to being Small portable devices are being used clinically in other areas able to access the umbilical catheters safely for infusions or of critical care.28 monitoring. One limitation of this study is the inexperience of the Using ultrasound, we significantly decreased the number of ultrasound-trained operators who may possibly misinterpret the radiographs per patient. Although the amount of radiation per findings for an umbilical line (that is, an orogastric tube or radiograph may be minimal, the additive effect in a hospitalized replogle in the esophagus) or failure to recognize high line (that newborn may be important. Studies have found that neonates are is, a high UAC with the lung in the window obscuring the view of exposed to an average of 9 to 31 X-rays during their hospitalization the aorta). Errors in interpretation are areas where increased to the NICU.19–22 The physical positioning of the infant required training and vigilance would be beneficial. General experience for different views can introduce instability for the infant and using ultrasound for catheter placement is currently limited. It is may displace the catheter(s). In our study, four patients in the unclear how much training is necessary to deem an individual ultrasound group required more than the requisite two X-rays. competent. Our unit is actively involved in the use of functional One was due to mistrust of the ultrasound findings when good echocardiography by neonatologists and fellows in training. Our blood return was noted by the fellow placing the lines. Two patients impression is that ultrasound-guided umbilical line placement is had known high placements of the catheters by the NNP who an easier technique to learn than echocardiography, but further wanted the X-ray with the high placed lines, despite ultrasound studies are required to evaluate teaching times and training information. The fourth patient was noted to have the line slip competencies. Although our study involved an extra individual in after suturing at the time the X-rays were taken. Each manipu- addition to the operator, the ultrasound probe can be sheathed lation of the catheter carries a risk of vessel trauma, infection or to enter the sterile field and be used by a single operator. thrombosis. Ultrasound allowed for fewer manipulations of UVC Finally, we were unable to use ultrasound to successfully guide lines and eliminated the need for X-ray confirmation that adds the venous umbilical catheter through the ductus venosus, despite radiation exposure and extra procedural time. direct visualization in cases when the catheter was repeatedly Unexpectedly, we also noted during preparation for this misplaced within the liver. On several attempts, the ductus venosus study that lower extremity movement affected umbilical catheter remained too narrow for even the smallest catheter to pass and positioning to a degree that may be clinically significant. We found suggests a basic anatomic limitation. Attempts to overcome the

Journal of Perinatology Ultrasound-guided umbilical catheter insertion in neonates SE Fleming and JH Kim 349 impasse using a second catheter on two occasions also met with 8 Jeng JJ, Kao HA, Jiang CJ, Guo HR. [A study of insertional length of umbilical artery failure. Further strategies to overcome this difficulty including catheters in newborns]. Zhonghua Min Guo Xiao Er Ke Yi Xue Hui Za Zhi 1989; mechanical and local pharmacologic dilatation may now be 30(2): 100–104. possible with direct visualization of the ductus venosus. 9 Baker DH, Berdon WE, James LS. Proper localization of umbilical arterial and venous catheters by lateral roentgenograms. Pediatrics 1969; 43(1): 34–39. 10 Butt WW, Whyte H. Blood pressure monitoring in neonates: comparison of Conclusion umbilical and peripheral artery catheter measurements. J Pediatr 1984; 105(4): 630–632. Ultrasound-guided insertion of umbilical catheters is a more 11 Kitterman JA, Phibbs RH, Tooley WH. 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Umbilical vein catheterization under that could be construed as a conflict of interest. None of the electrocardiogram guidance. Paediatr Anaesth 2005; 15(4): 297–300. original material contained in the manuscript has been previously 16 Biban P, Cavalli C, Santuz P, Soffiati M, Rugolotto S, Zangardi T. [Positioning of published nor is currently under review for publication elsewhere. umbilical vein catheter with ECG-guided technique: randomized study]. Acta Biomed Ateneo Parmense 2000; 71(Suppl 1): 647–650. 17 Raval NC, Gonzalez E, Bhat AM, Pearlman SA, Stefano JL. Umbilical venous catheters: Acknowledgments evaluation of radiographs to determine position and associated complications of malpositioned umbilical venous catheters. Am J Perinatol 1995; 12(3): 201–204. We thank all the healthcare professionals who helped with this study and all the 18 Kuschel CA. National Women’s Newborn Service’s Clinical GuidelineFUmbilical parents of the participating study infants. 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