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 OJN  Vol.10 No.10 , October 2020
A Review of Location Methods of Nasogastric Tube in Critically Ill Patients
Abstract: Nasogastric tube is widely used in intensive care units. The complications of misplacement are rare but very dangerous for critically ill patients. Accurate localization of the position of the tip of nasogastric tube can effectively decrease complications and ensure the safety of critically ill patients. There are various methods that can be used to verify the location of the nasogastric tube such as radiography, PH measurement, electromagnetic navigator and ultrasound. However, there is a lack of general consensus regarding a standard method. In this review, we found that the accuracy of nasogastric tube placement can be greatly improved by visual technology such as X-ray, sonography and electromagnetic navigator. However, visual technology has not been widely used to locate the tip of nasogastric tube in critically ill patients. Best practice guidelines based on the available knowledge and evidence of current methods are necessary to increase the accuracy placement of nasogastric tube. It is envisioned that development of visual technologies will determine a new standard of care for verification of placement of nasogastric tube.

1. Introduction

Nasogastric (NG) tube is widely used in intensive care units [1] [2] [3] [4]. The use of the NG tube has become used for several reasons, not only for the administration of enteral nutrition and medications, but also for gastric decompression. The annual application of NG tube reached 1.2 million in the United States [5]. However, NG tube misplacement has been reported in quite different frequencies: 1.9% - 89.5% in adults and 20.9% - 43.5% in children [6]. The complications of misplacement are very dangerous for patients [7]. The serious complications correlated with the maneuver derive from the possibility of misplacement in the tracheobronchial tree, pneumothorax, pneumomediastinum, subcutaneous emphysema, pneumonia, pulmonary hemorrhage, empyema, hemthorax, bronchopleural fistula, perforation of the esophagus or even death [8] - [13]. Therefore, accurate positioning of the tip of NG tube can effectively ensure the safety of critically ill patients. There are various methods that can be used to verify the location of the NG tube such as radiography, PH measurement, electromagnetic navigator and ultrasound [14]. However, there is a lack of general consensus regarding a standard method. The purpose of this review is to conduct a review of location methods of nasogastric tube in critically ill patients.

2. Non-Visualization Technology

2.1. Length Measurement

Insertion length of NG tube determined by the distance from the tip of the nose to the ear lobe and from the ear lobe to the xiphoid process of the sternum or the distance from the hairline of the forehead to the xiphoid process of the sternum [15]. Some scholars proposed that insertion length of NG tube should be extended 10 - 15 cm in adults [16] [17] [18]. A Meta analysis shows that extended insertion length of NG tube 10 cm can reduce the incidence of reflux, chocking coughs, aspiration, pneumonia [18] [19]. Other scholars improved the measurement methods for premature infants, neonates and catheterization [20] [21] [22]. However, these studies did not compare with X-ray and report the location of NG tube. Furthermore, this measuring method is affected by age, height, anatomical structure, body position and other factors [23] [24] [25]. Therefore, this method is limited to evaluate the placement of NG tube.

2.2. PH Measurement

The PH of gastric juice was 3.9, the PH of pulmonary bronchial secretion was 7.73, and the PH of intestinal juice was 7.35, which is used to distinguish the variety of liquid [26]. PH ≤ 5.5 is contributed to ensure placement of nasogastric tube [27] [28]. The sensitivity of a pH ≤ 5.5 to correctly identify gastric samples was 68% and the specificity was 79% [29]. The accuracy of this method was 94% in children [26]. The alert recommended testing with PH indicator paper as the first line check [30]. However, Borsci [31] found that in 45.7% of cases aspiration could not be achieved only using this method, and the likelihood of misreading the strips that may lead to errors of decision making with an adverse impact on a patient is 11.15%. The determination of PH value, considering a value lower than 5 as the cut-off for the correct placement, is not indicated in patients who take some medications, such as H2 blockers, and doesn’t distinguish between intestinal and tracheal placement [32]. Due to its uncertainty of this method, a cross-sectional survey in 383 intensive care units from 20 European countries reported that only 3.5% of ICUs used this method to confirm the location of nasogastric tube [4].

2.3. Auscultation of Injected Air

Hearing bubbling sound over epigastric region while air injected via tube perceived as evidence of NG tube placement. This method is widely used, and 51.93% - 84.7% of nurses used this method to confirm the location of NG tube [4] [33]. The uncertainty of this method was documented by American group Metheny in 1990 following a study. In the study, the average percentage of correct classifications was 34.4%, three subjects with feeding tubes inadvertently positioned in the respiratory tract, air insufflations were clearly audible in 2 of the 3 cases [34]. The accuracy of this method was 67% in children [26]. The effect of auscultation will be lower when nurses wear disposable caps, protective clothing and other personal protective equipment. Therefore, auscultation of injected air to predict NG tube location is unreliable and it should not be used alone [12] [30].

3. Visualization Technology

3.1. X-Ray

X-ray is the gold standard for NG tube placement [24] [32] [35] [36] [37] [38] [39]. This method can timely detect gastric tube heterotopia and prevent complications [35] [40]. This method was usually used to confirm the position of NG tube [37] [41]. However, due to the uncertainty of ray frequency and radiation exposure, it is not a first-line solution for the tip location of NG tube [4] [30] [42].

3.2. Sonography

Sonography was firstly used to confirm the tip of a naso-enteric tube feeding during the passing of pylorus in 1996 [43]. Bedside sonography is a sensitive method for confirming the position of NG tubes and performs in a shorter time than X-ray. Compared with X-ray, the sensitivity of sonography could reach 92.2% - 100%, and average time-consuming of this method was 42 - 140 s. [7] [37] [41] [44] [45] [46] [47]. The sensitivity of subxiphoid sonography and neck sonography and air-water mixture combined could be greatly increased [48]. The main difficulties were found in the visualization of the esophagogastric junction and the antrum in the transabdominal longitudinal scan in obese patients because of the interposition of gas. Left lateral decubitus and the injection of 50 ml of normal saline could facilitate the sonographic exam [7]. However, this location method is not wildly used in intensive care unit [4]. Further research should be conducted on the feasibility of nurses using sonography to verify the location of NG tube.

3.3. Endoscopy

Laryngoscope and gastroscope were used to NG tube placement [49] [50] [51] [52]. Laryngoscope can direct the NG tube into the esophagus. However, laryngoscope and gastroscopy are invasive procedures, and complications such as hypopharyngeal and esophageal perforation may occur [53]. Video-guided laryngoscope reduces nasogastric intubation time compared to manual and direct laryngoscope intubation [54]. However, endoscopic procedures may produce droplets which could increase the risk of respiratory infections among medical staffs. Due to the risk of respiratory and invasive injury, endoscopy was used for these mechanical ventilated patients who have difficult nasopharyngeal anatomy. These is no study to compare the effect of this method with X-ray. More researches are needed to explore the effect of endoscopy on location of NG tube.

3.4. Electromagnetic Navigator

Electromagnetic navigator was used to confirm the tip of a NG tube by Williamsin in 1996 [55]. Electromagnetic navigator is composed to electromagnetic transmitter, receiving device and display device. Electromagnetic transmitter is at the tip of the guide wire inside the nasogastric tube to monitor the position of the tip. Receiving device receives signal from electromagnetic transmitter and the placement of nasogastric tube could be visible through display device. The placement of an enteral feeding tube is also visible in critically ill patients with slow gastric emptying [56]. The sensivity of electromagnetic navigator was 98%, compared with chest X-ray [39]. This method is mainly applied to locate the nasojejunal tube [55] [56] [57] [58] [59]. It is needed to explore the effect of electromagnetic navigator on location of the tip of the NG tube.

4. Conclusions

NG tube is a common procedure in critically ill patients for feeding or drainage. The mistake placement would be leading to serious complications or fatal incidents. Therefore, it is necessary to confirm the location of the NG tube correctly. There are various methods that can be used to verify the location of the NG tube such as radiography, PH measurement, electromagnetic navigator and ultrasound. However, there is a lack of general consensus regarding a standard method.

In this review, we found that the accuracy of NG tube placement can be greatly improved by using visual technology such as X-ray, sonography and electromagnetic navigator. However, the visual technology has not been widely used to locate the tip of NG tube in critically ill patients. Visual technology to improve the accuracy and efficiency of placement and ongoing location verification is necessary. More researches are needed to verify NG tube location, develop potential solutions and actualize their use.

It may be that development of best practice guidelines for NG tube placement and ongoing location verification by a multiprofessional, collaborative team is warranted. Best practice guidelines based on the available knowledge and evidence of current methods are necessary to increase the accuracy placement of NG tube. It is envisioned that development of visual technologies will determine a new standard of care for verification of placement of NG tube. The goal is to minimize radiologic exposure and to improve safety for all patients who insert NG tube.

Funding

This study was supported by Nursing Research Foundation of Third Affiliated Hospital of Sun Yat-sen University (No. 201705) and Medical Scientific Research Foundation of Guangdong (No. A2018129), Science and Technology Achievement Transformation Project of Sun Yat-sen University (No. 82000-18843234).

NOTES

*These authors contributed equally to this work.

Cite this paper: Duan, M. , Chen, X. , Qin, X. , Liang, Q. , Dong, W. , Zhang, Y. and Lin, J. (2020) A Review of Location Methods of Nasogastric Tube in Critically Ill Patients. Open Journal of Nursing, 10, 943-951. doi: 10.4236/ojn.2020.1010065.
References

[1]   Mcclave, S.A., Taylor, B.E., Martindale, R.G., et al. (2016) Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). JPEN Journal of Parenteral and Enteral Nutrition, 40, 159-211.
https://doi.org/10.1177/0148607115621863

[2]   Singer, P., Blaser, A.R., Berger, M.M., et al. (2019) ESPEN Guideline on Clinical Nutrition in the Intensive Care Unit. Clinical Nutrition, 38, 48-79.
https://doi.org/10.1016/j.clnu.2018.08.037

[3]   Chapple, L.A., Chapman, M.J., Lange, K., et al. (2016) Nutrition Support Practices in Critically Ill Head-Injured Patients: A Global Perspective. Critical Care, 20, 6.
https://doi.org/10.1186/s13054-015-1177-1

[4]   Roynette, C.E., Bongers, A., Fulbrook, P., et al. (2008) Enteral Feeding Practices in European ICUs: A Survey from the European Federation of Critical Care Nursing Associations (EfCCNa). e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism, 3, e33-e39.
https://doi.org/10.1016/j.eclnm.2007.10.004

[5]   Heidarzadi, E., Jalali, R., Hemmatpoor, B., et al. (2020) The Comparison of Capnography and Epigastric Auscultation to Assess the Accuracy of Nasogastric Tube Placement in Intensive Care Unit Patients. BMC Gastroenterology, 20, 196.
https://doi.org/10.1186/s12876-020-01353-5

[6]   Ellett, M.L. (2004) What Is Known about Methods of Correctly Placing Gastric Tubes in Adults and Children. Gastroenterology Nursing, 27, 253-259, 260-261.
https://doi.org/10.1097/00001610-200411000-00002

[7]   Zatelli, M. and Vezzali, N. (2017) 4-Point Ultrasonography to Confirm the Correct Position of the Nasogastric Tube in 114 Critically Ill Patients. Journal of Ultrasound, 20, 53-58.
https://doi.org/10.1007/s40477-016-0219-0

[8]   Lei, Q.L., Zhang, Z., Dong, Y.T., et al. (2012) Causes and Preventive Treatment of a Case of Gastrointestinal Decompression Tube Strayed into the Trachea for Excessively Long Indwelling. Chinese Journal of Modern Nursing, 18, 3190-3191.

[9]   Miller, K.S., Tomlinson, J.R. and Sahn, S.A. (1985) Pleuropulmonary Complications of Enteral Tube Feedings. Two Reports, Review of the Literature, and Recommendations. Chest, 88, 230-233.
https://doi.org/10.1378/chest.88.2.230

[10]   Metheny, N.A., Meert, K.L. and Clouse, R.E. (2007) Complications Related to Feeding Tube Placement. Current Opinion in Gastroenterology, 23, 178-182.
https://doi.org/10.1097/MOG.0b013e3280287a0f

[11]   Siemers, P.T. and Reinke, R.T. (1976) Perforation of the Nasopharynx by Nasogastric Intubation: A Rare Cause of Left Pleural Effusion and Pneumomediastinum. American Journal of Roentgenology, 127, 341-343.
https://doi.org/10.2214/ajr.127.2.341

[12]   Metheny, N.A. and Meert, K.L. (2014) A Review of Published Case Reports of Inadvertent Pulmonary Placement of Nasogastric Tubes in Children. Journal of Pediatric Nursing, 29, e7-e12.
https://doi.org/10.1016/j.pedn.2013.08.009

[13]   Fonseca, V.R., Domingos, G., Alves, P., et al. (2015) Placement of Nasogastric Tube Complicated by Hydropneumothorax. Intensive Care Medicine, 41, 1969-1970.
https://doi.org/10.1007/s00134-015-3824-z

[14]   Bliss, D.Z. (2000) pH and Concentration of Bilirubin in Feeding Tube Aspirates as Predictors of Tube Placement. Journal of Parenteral and Enteral Nutrition, 24, 187-188.
https://doi.org/10.1177/0148607100024003187

[15]   Li, X.H. (2006) Basic Nursing. People’s Medical Publishing House, Beijing, 209-211.

[16]   Zuo, J.M., Chen, H.M., Lan, H., et al. (2016) Comparison on Applied Effect of Remain Length of 3 Kinds of Gastric Tube in Patients with Stroke. Chinese Nursing Research, 30, 1755-1757.
https://doi.org/10.7748/ns.30.30.14.s16

[17]   Chen, H.M., Lan, H., Wu, J.B. and Zhang, W. (2016) Effects of Gastric Tube Indwelling with Difference Lengths in Patients with Stroke. Chinese Journal of Modern Nursing, 22, 761-765.

[18]   Wang, J., Pi, H.Y. and Guo, L.M. (2015) Influences of Extension of Insertion Length of Nasogastric Tube 10 cm on the Relevant Complication of Patients with Nasal Feeding. Nursing Journal of Chinese People’s Liberation Army, 32, 6-10.

[19]   Ding, N.N., Zhang, C.Y., Yao, L., et al. (2019) Effect of Modified Measurement of Gastric Tube Placement Length on Neonatal Nasal Feeding: A Meta-Analysis. Chinese Nursing Research, 33, 1498-1504.

[20]   Fernandez, R.S., Chau, J.P., Thompson, D.R., et al. (2010) Accuracy of Biochemical Markers for Predicting Nasogastric Tube Placement in Adults—A Systematic Review of Diagnostic Studies. International Journal of Nursing Studies, 47, 1037-1046.
https://doi.org/10.1016/j.ijnurstu.2010.03.015

[21]   Xie, S.H., Ma, A.P., Zhang, X.X., et al. (2015) Study on the Effect of Gastrointestinal Decompression and the Length of Gastric Tube Placement in Very Low Birth Weight Infants. Journal of Nurses Training, No. 12, 1123-1124.

[22]   Guo, M.Y., Tian, B.J. and Xiao, T. (2017) Comparison on Gastric Lavage Effect of Remain Length of 2 Kinds of Gastric Tube in Patients with Poisoned. Today Nurse, No. 6, 123-124.

[23]   Jin, X.J. and Tao, M.Q. (2015) The Review of Correctly Locating the Length of Nasogastric Tube. Nursing and Rehabilitation Journal, 14, 1022-1025.

[24]   Dias, F., Jales, R.M., Alvares, B.R., et al. (2020) Randomized Clinical Trial Comparing Two Methods of Measuring Insertion Length of Nasogastric Tubes in Newborns. JPEN Journal of Parenteral and Enteral Nutrition.
https://doi.org/10.1002/jpen.1786

[25]   Zhang, Y., Jin, T.C. and Wang, H.L. (2002) Relationship between Length of Gastric Tube Insertion and Height. Chinese Journal of Digestion, 22, 758.

[26]   Wang, Y. and Zuo, Z.L. (2008) Research on Nasogastic Tube Location of Children by Testing pH Level in Feeding Tube. Chinese Journal of Nursing, No. 9, 835-836.

[27]   Tang, L., Zhang, L. and Wu, H.P. (2012) Systematic Evaluation of the Position of Nasogastric Tube to Measure the pH of Aspirated Material. Chinese Journal of Practical Nursing, 28, 57-59.

[28]   Lyman, B., Kemper, C., Northington, L., et al. (2016) Use of Temporary Enteral Access Devices in Hospitalized Neonatal and Pediatric Patients in the United States. Journal of Parenteral and Enteral Nutrition, 40, 574-580.
https://doi.org/10.1177/0148607114567712

[29]   Rowat, A.M., Graham, C. and Dennis, M. (2018) Study to Determine the Likely Accuracy of pH Testing to Confirm Nasogastric Tube Placement. BMJ Open Gastroenterology, 5, e211.
https://doi.org/10.1136/bmjgast-2018-000211

[30]   Stroud, M., Duncan, H. and Nightingale, J. (2003) Guidelines for Enteral Feeding in Adult Hospital Patients. Gut, 52, i1-i12.
https://doi.org/10.1136/gut.52.suppl_7.vii1

[31]   Borsci, S., Buckle, P., Huddy, J., et al. (2017) Usability Study of pH Strips for Nasogastric Tube Placement. PLoS ONE, 12, e189013.
https://doi.org/10.1371/journal.pone.0189013

[32]   Irving, S.Y., Rempel, G., Lyman, B., et al. (2018) Pediatric Nasogastric Tube Placement and Verification: Best Practice Recommendations from the NOVEL Project. Nutrition in Clinical Practice, 33, 921-927.
https://doi.org/10.1002/ncp.10189

[33]   Feng, L.M., Shen, M.F., Mei, B.B., et al. (2018) Investigation on Methods Used by Nurses to Verify Nasogastric Tube Placement: The Influencing Factors. Journal Nursing Science, 33, 5-8.

[34]   Metheny, N., Mcsweeney, M., Wehrle, M.A., et al. (1990) Effectiveness of the Auscultatory Method in Predicting Feeding Tube Location. Nursing Research, 39, 262-267.
https://doi.org/10.1097/00006199-199009000-00002

[35]   Bankier, A.A., Wiesmayr, M.N., Henk, C., et al. (1997) Radiographic Detection of Intrabronchial Malpositions of Nasogastric Tubes and Subsequent Complications in Intensive Care Unit Patients. Intensive Care Medicine, 23, 406-410.
https://doi.org/10.1007/s001340050348

[36]   Irving, S.Y., Lyman, B., Northington, L., et al. (2014) Nasogastric Tube Placement and Verification in Children: Review of the Current Literature. Nutrition in Clinical Practice, 29, 267-276.
https://doi.org/10.1177/0884533614531456

[37]   Zhang, X.J., Si, Q., Zheng, C., et al. (2018) Simplified Bedside Ultrasound Method in Confirming the Correct Location of Nasointestinal Tube in Critically Ill Patients. Chinese Journal of Medical Ultrasound (Electronic Edition), 15, 464-468.

[38]   Mcfarland, A. (2017) A Cost Utility Analysis of the Clinical Algorithm for Nasogastric Tube Placement Confirmation in Adult Hospital Patients. Journal of Advanced Nursing, 73, 201-216.
https://doi.org/10.1111/jan.13103

[39]   Bear, D.E., Champion, A., Lei, K., et al. (2016) Use of an Electromagnetic Device Compared with Chest X-Ray to Confirm Nasogastric Feeding Tube Position in Critical Care. Journal of Parenteral and Enteral Nutrition, 40, 581-586.
https://doi.org/10.1177/0148607115575034

[40]   Bhakta, P., Keady, T. and O’Brien, B. (2018) Nasogastric Tube Location: A Diagnostic Dilemma. Canadian Journal of Anesthesia, 65, 839-840.
https://doi.org/10.1007/s12630-018-1089-z

[41]   Ye, R.Z., Fan, X.M., Sun, R.H., et al. (2017) Quick Confirmation of Nasointestinal Tube Placed below Pylorus in Critically Ill Patients by Duodenal Bulb Ultrasonic Anatomy Locating Method. National Medical Journal of China, 97, 1312-1315.

[42]   Kleinerman, R.A. (2006) Cancer Risks Following Diagnostic and Therapeutic Radiation Exposure in Children. Pediatric Radiology, 36, 121-125.
https://doi.org/10.1007/s00247-006-0191-5

[43]   Hernández-Socorro, C.R., Marin, J., Ruiz-Santana, S., et al. (1996) Bedside Sonographic-Guided versus Blind Nasoenteric Feeding Tube Placement in Critically Ill Patients. Critical Care Medicine, 24, 1690-1694.
https://doi.org/10.1097/00003246-199610000-00015

[44]   Atalay, Y.O., Aydin, R., Ertugrul, O., et al. (2016) Does Bedside Sonography Effectively Identify Nasogastric Tube Placements in Pediatric Critical Care Patients? Nutrition in Clinical Practice, 31, 805-809.
https://doi.org/10.1177/0884533616639401

[45]   Atalay, Y.O., Polat, A.V., Ozkan, E.O., et al. (2019) Bedside Ultrasonography for the Confirmation of Gastric Tube Placement in the Neonate. Saudi Journal of Anaesthesia, 13, 23-27.

[46]   Vigneau, C., Baudel, J.L., Guidet, B., et al. (2005) Sonography as an Alternative to Radiography for Nasogastric Feeding Tube Location. Intensive Care Medicine, 31, 1570-1572.
https://doi.org/10.1007/s00134-005-2791-1

[47]   Lin, T., Gifford, W., Lan, Y., et al. (2017) Diagnostic Accuracy of Ultrasonography for Detecting Nasogastric Tube (NGT) Placement in Adults: A Systematic Review and Meta Analysis. International Journal of Nursing Studies, 71, 80-88.
https://doi.org/10.1016/j.ijnurstu.2017.03.005

[48]   Yıldırım, Ç., Coşkun, S., Gökhan, et al. (2018) Verifying the Placement of Nasogastric Tubes at an Emergency Center: Comparison of Ultrasound with Chest Radiograph. Emergency Medicine International, 2018, Article ID: 2370426.
https://doi.org/10.1155/2018/2370426

[49]   Hou, W.L., Hou, Y.H. and Zhang, H. (2011) An Improved Method of Placing Nasogastric Tube beside bed by Gastroscope. China Journal of Emergency Resuscition and Disaster Medicine, 6, 283.

[50]   Du, X.D., Luan, X.Y., Yang, Y., et al. (2004) Fiberoptic Laryngoscope Guided Gastric Tube Insertion. Journal of Clinical Otorhinolaryngology, 18, 181-182.

[51]   Jiao, X.F., Li, W.L., Niu, X.G., et al. (2012) The Application of Feeding Tube Instead of Nasogastic Tube under Gastroscope in Critical Patients. China Journal of Endoscopy, 18, 1033-1037.

[52]   Wang, D.Q. and Zhang, L.B. (2007) The Application of Video Laryngoscope in Patients with Gastic Tube Insertion Difficulty. Chinese Journal of Nursing, 42, 1041-1042.

[53]   Baum, E.D., Elden, L.M., Handler, S.D., et al. (2008) Management of Hypopharyngeal and Esophageal Perforations in Children: Three Case Reports and a Review of the Literature. Ear, Nose & Throat Journal, 87, 44-47.
https://doi.org/10.1177/014556130808700115

[54]   Lee, X.L., Yeh, L.C., Jin, Y.D., et al. (2017) Nasogastric Tube Placement with Video-Guided Laryngoscope: A Manikin Simulator Study. Journal of the Chinese Medical Association, 80, 492-497.
https://doi.org/10.1016/j.jcma.2017.01.009

[55]   Williams, A.J., Fraser, R., Chorley, D.P., et al. (1996) The Cathlocator: A Novel Non-Radiological Method for the Localization of Enteral Tubes. Journal of Gastroenterology and Hepatology, 11, 500-505.
https://doi.org/10.1111/j.1440-1746.1996.tb00298.x

[56]   Young, R.J., Chapman, M.J., Fraser, R., et al. (2005) A Novel Technique for Post-Pyloric Feeding Tube Placement in Critically Ill Patients: A Pilot Study. Anaesthesia and Intensive Care, 33, 229-234.
https://doi.org/10.1177/0310057X0503300212

[57]   Zhang, X., Xiang, M.F., Zhou, H.L., et al. (2015) Application of Electromagnetic Navigation Localization in Indwelling Jejunum Feeding Tube through Nose for Critical Patients. Chinese Journal of Nursing, 50, 824-827.

[58]   Xiao, J.G., Zhou, F.H., Liu, H., et al. (2015) A New Method of Placement of Naso-Jejunum Feeding Tube Guided by Electromagnetic Positioning Navigator. Medical Journal of Chinese People’s Liberation Army, 40, 833-836.

[59]   Wang, X., Zhang, L., Wu, C., et al. (2014) The Application of Electromagnetically Guided Post-Pyloric Feeding Tube Placement in Critically Ill Patients. Journal of Investigative Surgery, 27, 21-26.
https://doi.org/10.3109/08941939.2013.826310

 
 
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