The authors thank Dr. Lee Khai Pin, Head &#38; Senior Consultant, Children&#39;s Emergency, KK Women&#39;s and Children&#39;s Hospital, 100 Bukit Timah Road, Singapore for the administrative support with the video article production.&#160;Article reproduced with permission from &#8220;Handheld Metal Detector for Metallic Foreign Body Ingestion in Pediatric Emergency&#8221;; August 2018: 85(8):618&#8211;624; Hazwani Binte Hamzah, Vigil James, Suraj Manickam, Sashikumar Ganapathy: copyright The Indian Journal of Pediatrics.

The protocol follows the guidelines of Institutional Human Research Ethics committee. The central institutional review board provided the ethics approval for the study.
1. Participant Screening
<ol>
	<li>Recruit patients who present to the pediatric emergency department with history of foreign body ingestion.</li>
	<li>Exclude the patients who are in respiratory distress and has implanted devices like pace makers.</li>
</ol>
2. Prepare the Patient
<ol>
	<li>Dress the patient in a hospital gown.</li>
	<li>Remove all items that may contain metallic objects such as clothes, eye glasses, earrings, pendants, and ornaments prior to the examination to avoid interference with the HHMD screening.</li>
	<li>Place the patient in the center of the room away from other potential metallic interferences.</li>
</ol>
3. Prepare the Examiner and Caregivers
<ol>
	<li>Remove all metallic accessories such as jewelry and watch.</li>
	<li>Request the caregiver to remove all metallic accessories such as jewelry and watch.</li>
</ol>
4. Metal Detector Screening
<ol>
	<li>Use the HHMD (Figure 1) to conduct the screening.</li>
	<li>Confirm the working status of the HHMD by eliciting a positive audio-visual signal by waving over a piece of metal.</li>
	<li>Perform the HHMD scanning in a standing position for bigger children.</li>
	<li>Perform the HHMD scanning in an erect position for infants by having the caregiver hold the patient appropriately.</li>
	<li>Hold the hands of the patient up and away from the body.</li>
	<li>Position the head of the patient in extension to expose the neck.</li>
	<li>Scan from the level of the chin to the level of hip joint to cover the anatomical areas from neck to pelvis.</li>
	<li>Perform the scan in a zig-zag manner across the body to ensure that every area has been scanned.</li>
	<li>Scan both anteriorly and posteriorly as the thickness of patient must be taken into consideration.</li>
	<li>Carefully note the positive audio-visual signal during the scanning for the presence of MFBs.</li>
</ol>
5. Perform the Relevant Radiograph
<ol>
	<li>Order the relevant radiograph of the neck, chest, or abdomen, as per the area detected by the HHMD screening for the MFBs.</li>
	<li>Proceed with all the X-ray views (neck, chest, and abdomen) if the MFB was not detected during HHMD screening and the clinical index of suspicion for foreign body ingestion is high.</li>
</ol>
6. Record the Test Results
<ol>
	<li>Record the test results in the logbook (Figure 2) specifically created based on the workflow (Figure 1).</li>
	<li>Correlate the positive audio-visual HHMD signal with the underlying bony landmark on the body, by palpating the following prominent bony landmarks - sternal notch, xiphisternum, pubic symphysis, and bilateral Iliac crest.</li>
	<li>Record the landmark on the logbook&#39;s anatomical reference outline before proceeding with the X-ray examination.</li>
</ol>

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A., Forte, V., Papsin, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+a+commercially+available+metal+detector+for+the+localization+of+metallic+foreign+body+ingestion+in+children.">Use of a commercially available metal detector for the localization of metallic foreign body ingestion in children.</a> The Journal of Otolaryngology. 29 (4), 218-220 (2000).</li><li>Sacchetti, A., Carraccio, C., Lichenstein, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hand-held+metal+detector+identification+of+ingested+foreign+bodies.">Hand-held metal detector identification of ingested foreign bodies.</a> Pediatric Emergency Care. 10 (4), 204-207 (1994).</li><li>Hamzah, H. B., James, V., Manickam, S., Ganapathy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Handheld+Metal+Detector+for+Metallic+Foreign+Body+Ingestion+in+Pediatric+Emergency.">Handheld Metal Detector for Metallic Foreign Body Ingestion in Pediatric Emergency.</a> Indian Journal of Pediatrics. 85 (8), 618-624 (2018).</li><li>Doraiswamy, N. V., Baig, H., Hallam, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+detector+and+swallowed+metal+foreign+bodies+in+children.">Metal detector and swallowed metal foreign bodies in children.</a> Journal of Accident &amp; Emergency Medicine. 16 (2), 123-125 (1999).</li><li>Seikel, K., Primm, P. A., Elizondo, B. J., Remley, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Handheld+metal+detector+localization+of+ingested+metallic+foreign+bodies:+accurate+in+any+hands.">Handheld metal detector localization of ingested metallic foreign bodies: accurate in any hands.</a> Archives of Pediatrics &amp; Adolescent Medicine. 153 (8), 853-857 (1999).</li><li>Lemberg, P. S., Darrow, D. H., Holinger, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aerodigestive+tract+foreign+bodies+in+the+older+child+and+adolescent.">Aerodigestive tract foreign bodies in the older child and adolescent.</a> The Annals of Otology, Rhinology, and Laryngology. 105 (4), 267-271 (1996).</li><li>Stack, L. B., Munter, D. 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The authors have nothing to disclose.

Metallic foreign body ingestion in children is a common problem and in the majority of patients, this is managed conservatively7,16. Single or repeated radiographs can expose the radio-sensitive pediatric population to unwanted radiation risk while attempting to localize the ingested metallic foreign body. Several studies have described the use of metal detectors in MFB ingestion in children, with sensitivity more than 96% and specificity greater than 80%1,7,17,18,19. Metal detector has an inherent oscillating circuit which is altered in the presence of a metallic device causing a disturbance in its electro-magnetic field1. This results in the generation of the sound alarm and visual signal from an audio-piezo material in the device20,21. Metal detectors can detect both non-magnetic and magnetic materials such as iron, silver, lead, aluminum, copper, and brass5.
As reported in the previous studies, coins were the most common MFBs detected in our study22,23. In our study, all the swallowed metallic coins were identified by the metal detector as accurately as that done by the plain radiograph. Ingested coins have a propensity to get impacted in the thoracic inlet24 and hence limited radiographs of the chest may overlook the metallic foreign body. This was evident in one patient prior to the initiation of this study (Figure 4). Previous studies have shown that a short-term training was adequate to accurately perform handheld metal detector examination and the difference between experienced and inexperienced examiners is not significant statistically3,4,6,22. Hence a &#34;see one, do one, and teach one&#34; approach can help achieve proficiency in the metal detector examination. The metal detector examination can be thoroughly performed in less than 2 minutes5. Hence, the handheld metal detector screening can be introduced early in the triage process of children with high suspicion of metallic foreign body ingestion. This can help to limit the number of radiographs being ordered for the patient to localize the metallic foreign body.
In patients with an unreliable history of metallic foreign body ingestion, the results of handheld metal detector screening must be interpreted with caution. A negative metal detector screening does not negate the need for radiograph evaluation. The authors recommend the use of further detailed diagnostic imaging if a foreign body other than coin was ingested or the patient is overtly symptomatic, in order to prevent missing a foreign body. For those children presenting to the emergency department with outside radiographs,&#160;already done to localize the metallic foreign body, metal detector screening can help minimize the need for repeat radiographs.
Repeat radiographs are often necessary for localization of the foreign body prior to the definitive procedure for removal of the foreign body. They can expose the patients to additional radiation and add on to the treatment expense. Use of HHMD screening can help preclude repeated radiographs and concurrent cost by providing useful preoperative information6. HHMD can be used to perform repeat examinations and accurately localize the metallic foreign body while the patient is awaiting endoscopic removal, because sometimes several hours may lapse before the definitive treatment is performed4,6. Handheld metal detector is a very valuable tool in the follow-up of the course and passage of ingested metallic foreign bodies, which are identified positive during the initial presentation to the emergency department3. The use of metal detector screening may effectively replace repeat radiography for the follow-up of metallic foreign body expulsion from the body6. The use of HHMD re-screening can also negate the practice of routinely examining the stools for foreign bodies, which is messy and unreliable and may lead to unnecessary anxiety in the caregivers, if there is a failure to detect the foreign body1.
There were two aluminum foreign bodies in our study that were missed on plain radiograph but detected on metal detector screening. The invisibility of aluminum objects in plain radiographs, due to its relative radiolucency22, has been previously documented in literature. Aluminum objects can be very difficult to detect even using a thin barium swallow technique2. X-ray absorption of a metal is determined based on the fraction of the third power of atomic number and energy of the X-ray beam. In most of the emergency department settings, energy of the X-ray beam is constant. Aluminum has an atomic number of only 13 and hence it remains relatively radiolucent. Metal detectors are more sensitive than plain radiographs in the detection and localization of aluminum foreign bodies20,21,22.
The metal detector screening is limited by the fact that even though it might accurately identify the presence of a coin in the neck, the metal detector cannot differentiate between airway or upper gastrointestinal tract location of the MFB. This could have serious implications in the retrieval of foreign body. HHMD examination is unreliable for very small metallic foreign body ingestion like metallic battery, screws, hairpin, and stapler pin25. Profound obesity is a relative contraindication for metal detector examination due to the relative increased distance from metallic objects to the scanner1.
The critical step in the HHMD screening protocol is to remove all items, which could contain metallic objects such as clothes, eyeglasses, earrings, pendants, and ornaments prior to the examination to avoid interference with the HHMD screening. Also, the patient must be placed in the center of the room at least 1-m away from other potential metallic interferences. It is also of paramount importance for the examiners and caregivers to remove all metallic accessories like jewelry and watch. Prior to the initiation of the HHMD screening, confirm the working status of the handheld metal detector, by eliciting a positive audio-visual signal, by waving over a piece of metal. In case of a negative signal, change the batteries and re-attempt. If the signal persists to be negative, an alternative HHMD in working condition should be used. Ideally, the HHMD scanning should be done in a standing position, with hands of the patient up and away from the body. This technique can be modified in infants by requesting the caregivers to hold the patient in the erect position. The head of the patient must be in extension to expose the neck. In order to avoid missing an MFB during the screen, ensure that the scan is done from the level of the chin to the level of the hip joint in a zig-zag manner across the body, both anteriorly and posteriorly.
In conclusion, our study demonstrates that HHMD can be safely and reliably used as a screening tool in the process of detecting ingested coins and coin-like MFBs. The plain radiograph still remains the gold standard to detect sharp metallic objects as well as button batteries, the management of which is very time-sensitive. In order to confirm the expulsion of the metallic foreign body during the follow-up visit, HHMD can be used as an effective screening tool. For the detection of radiolucent foreign bodies such as those composed of pure aluminum, HHMD is more sensitive than the conventional X-ray examination. The HHMD being a pain free tool with prominent audio-visual signals can keep young children happy and engaged during the examination process21. A metal detector can also be a valuable tool in an office-based practice to help detect metallic foreign bodies prior to referring the patient to an emergency department.

Foreign body ingestion is a widespread problem among children presenting to the pediatric emergency department because of the natural inquisitive nature of infants and children to explore objects by tasting and swallowing them1,2. Previous studies have reported that metallic objects constituted 85% of all foreign body ingestions in their cohort of patients3,4. The goal of this protocol is to assess the accuracy and feasibility of using a handheld metal detector to detect ingested metallic foreign bodies in children. We propose that by introducing the handheld metal detector screening protocol early in the triage process of children with high suspicion of metallic foreign body ingestion, the number of radiographs being ordered to localize the metallic foreign body can be reduced in this radio-sensitive population.
Handheld metal detector (HHMD) is an inexpensive, easily accessible adjunct that can help expedite the management of ingested metallic foreign bodies. Metal detector is a very low frequency device, which has a receiver and a transmitter that detects the change in its electromagnetic field caused by the presence of a metallic object in its vicinity3. If a metallic object is within the field, the electromagnetic field is disrupted and the sensor will set off an audio-visual alarm on the device4. The metal detector examination can be thoroughly performed in less than 2 minutes5. Hence, the HHMD screening can be introduced early in the triage process of children with high suspicion of metallic foreign body ingestion for topographical localization.
Coins are the most common swallowed metallic foreign bodies1,4,6,7. Due to the lack of sharp edges and general non-toxic nature, the majority of coin ingestions are managed conservatively. Other types of materials commonly ingested include magnets, button batteries, small toys, peanuts, jewelry, buttons, bones, seeds, and popcorn8,9. Impaction of foreign bodies most commonly occurs in the esophagus at three sites, namely upper esophageal sphincter, mid-esophagus at the level of aortic arch, and lower esophageal sphincter10. Metallic foreign bodies (MFBs) located in the esophagus may be asymptomatic in 40% of patients11,12 and its prolonged impaction can lead to various complications like esophageal perforation, mediastinitis, tracheoesophageal fistula, tracheal stenosis, and aorto-esophageal fistulas1,13,14,15. Other locations of foreign body impaction include pylorus, duodenum, and ileo-caecal junction10.
Performing radiographs of neck, chest, and abdomen to diagnose suspected foreign body ingestion is a widespread practice in the emergency departments5. Among all types of the ingested foreign bodies, only 10% are radio-opaque10. The radiological tests are time-consuming and have a risk of radiation exposure in children. Precise topographical localization of ingested metal objects is very crucial to guide therapy. The introduction of HHMD screening early in the triage process can help mitigate extraneous ordering of radiographs by topographically localizing the ingested metallic foreign body.
This study evaluated the accuracy of HHMD to localize MFBs in a systematic topographic fashion and determined the effectiveness and feasibility of HHMD in the local Pediatric population. We also examined how well this radiation free screening tool was accepted by the patients and parents. Between May and July 2016, all the consecutive patients who presented to the pediatric emergency department with a history of foreign body ingestion were included in the study. Informed consent was obtained from the parent or legal guardian. Patients with alleged foreign body ingestion were systematically scanned using HHMD. The gold standard of care for identification and localization of ingested metallic foreign bodies is performing plain radiographs of the cervical area, thorax, and abdomen. To facilitate the conduct of the study, a standardized workflow was created (Figure 1). A log book specifically created based on the workflow was used to collect the initial data, which were subsequently transcribed to a spreadsheet (Figure 2). The data in the result section are depicted as the number of cases followed by percentages.

<table>
	<tbody>
		<tr>
			<td>Hand held metal detector</td>
			<td>Garrett Super Scanner V</td>
			<td>NA</td>
			<td>NA</td>
		</tr>
	</tbody>
</table>

handheld metal detector screening for metallic foreign body ingestion in children

Coins are the most common ingested metallic foreign bodies among children. The goal of this protocol is to assess the accuracy and feasibility of using a handheld metal detector to detect ingested metallic foreign bodies in children. We propose that by introducing handheld metal detector screening early in the triage process of children with high suspicion of metallic foreign body ingestion, the number of radiographs being ordered to localize the metallic foreign body can be reduced in this radio-sensitive population. The study protocol requires the screening of the participants for history of foreign body ingestion and exclusion of patients with respiratory distress or metallic implants. The patient changes to hospital gown and items that could contain metal like eyeglasses, earrings, pendants, and ornaments are removed. The patient is positioned in the center of the room away from other metallic interferences. The working status of the handheld metal detector is first confirmed by eliciting a positive audio-visual signal. Then the screening is done in an erect position with head in extension to expose the neck, from the level of the chin to the level of the hip joint, to cover the anatomical areas from neck to pelvis in a zig-zag manner both anteriorly and posteriorly. A positive audio-visual signal is carefully noted during the scanning for the presence of metallic foreign body. Relevant radiographs are ordered as per the area detected on the metal detector screening. The handheld metal detector was able to precisely identify all the coins among the ingested metallic foreign bodies in our study. The handheld metal detector could not consistently detect non-coin metallic foreign bodies. This protocol demonstrates the accuracy of handheld metal detector in the identification and localization of coins and coin like metallic foreign bodies.

The researchers recruited 36 patients for this observational study. These patients had presented to the pediatric emergency department with a history of foreign body ingestion. Among these, 28 patients had metallic foreign body ingestions (Figure 3). The remaining 8 patients had ingested non-metallic foreign bodies such as fish bones, satay stick, and plastic button. Coins were the most common type of foreign body ingested (Table 1), which comprised 30.5% of the patients. The other most common foreign bodies that were ingested included fish bone, toy parts, button battery, and metallic screws.
The HHMD examination was performed as per the standardized protocol for all the patients who had a strong history of MFB ingestion. This was followed by radiograph of a relevant area, if the MFB was detected during HHMD screening. The remaining patients, who had a strong history of foreign body ingestion and a negative HHMD screening, underwent radiographs of neck, chest, and abdomen. HHMD was able to precisely identify all the coins among the ingested MFBs in our study. The overall sensitivity of HHMD to detect coin was 100%. The specificity of HHMD to detect the coins was 100%. The positive and negative predictive value for the detection of coins using HHMD was 100% each.
Non-coin MFBs such as metallic screw, needle, and stapler pin which contributed to 13.7% of all ingestions, were not identified by the HHMD. However, these foreign bodies were not detected on the plain radiographs neither. This could be explained by the fact that either the foreign bodies were expelled, or the history of ingestion itself was questionable. For the patients who had ingested toys or toy parts, button battery, hair clip, metal ball, and metal screws (overall representing 30.2% of patients), the ability of the HHMD to detect the foreign bodies during the screening was similar to that by radiograph evaluation. All the metallic objects identified by the plain radiograph in this study were also accurately detected by the HHMD.
There were ingestions of a coke can flip top and a pendant (both composed of exclusive aluminium metal). Both these foreign bodies were accurately identified during the metal detector screening. However, these aluminum-containing foreign bodies were not visible on the plain radiographs, which were reviewed by both the pediatric emergency physicians and radiologists.
A post-procedure survey conducted among the HHMD users suggested that none of the members of the study team had difficulty explaining the protocol of HHMD use to the caregivers. The majority of the caregivers agreed to the fact that HHMD was able to detect the ingested metallic foreign body (77.7%). Further, 75% of the parents felt that by using HHMD, the need for X-ray examination for foreign body ingestion can be reduced. The main barriers to implementing HHMD in the workflow reported by the pediatric emergency physicians were patients&#39; limitations as exclusion criteria, parents&#39; choice, and clinician&#39;s preference.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58468/58468fig1.jpg" /> 
Figure 1: Workflow for the use of handheld metal detector. The handheld metal detector is depicted in the figure highlighting the visual signals. This flowchart has been modified from Hamzah et al. 201820. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58468/58468fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58468/58468fig2.jpg" /> 
Figure 2: Logbook used to record the patient details. The anatomical area of the audio-visual signal is marked on the figure. Also recorded are the details of the X-ray requested and X-ray performed. This figure has been modified from Hamzah et al. 201820. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58468/58468fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58468/58468fig3.jpg" /> 
Figure 3: Patient recruitment flowchart. This flowchart has been adapted from Hamzah et al. 201820. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58468/58468fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58468/58468fig4.jpg" /> 
Figure 4: Missed MFB on routine chest-abdominal radiograph but detected on repeat neck radiograph. This figure has been adapted from Hamzah et al. 201820. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58468/58468fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Type of FB</td>
			<td>No of Cases (%)</td>
			<td>Was HMD used?</td>
			<td>Was HMD able to locate FB?</td>
			<td>Was radiograph positive?</td>
		</tr>
		<tr>
			<td>Coin#</td>
			<td>11 (30.5%)</td>
			<td>Yes</td>
			<td>11 positives</td>
			<td>11 positives</td>
		</tr>
		<tr>
			<td>Fishbone%</td>
			<td>6 (16.6%)</td>
			<td>No</td>
			<td>Not applicable</td>
			<td>4 positives, 2 negatives</td>
		</tr>
		<tr>
			<td>Toys or toy parts#</td>
			<td>5 (13.8%)</td>
			<td>Yes</td>
			<td>2 positives, 3 negatives</td>
			<td>2 positives, 3 negatives</td>
		</tr>
		<tr>
			<td>Battery#</td>
			<td>3 (8.3%)</td>
			<td>Yes</td>
			<td>1 positive, 2 negatives</td>
			<td>1 positive, 2 negatives</td>
		</tr>
		<tr>
			<td>Screws#</td>
			<td>3 (8.3%)</td>
			<td>Yes</td>
			<td>3 negatives</td>
			<td>3 negatives</td>
		</tr>
		<tr>
			<td>Hairclip#</td>
			<td>1 (2.7%)</td>
			<td>Yes</td>
			<td>1 positive</td>
			<td>1 positive</td>
		</tr>
		<tr>
			<td>Needle#</td>
			<td>1 (2.7%)</td>
			<td>Yes</td>
			<td>1 negative</td>
			<td>1 negative</td>
		</tr>
		<tr>
			<td>Coke can flip top#*</td>
			<td>1 (2.7%)</td>
			<td>Yes</td>
			<td>1positive</td>
			<td>1 negative</td>
		</tr>
		<tr>
			<td>Satay stick%</td>
			<td>1 (2.7%)</td>
			<td>No</td>
			<td>Not applicable</td>
			<td>1 positive</td>
		</tr>
		<tr>
			<td>Metal object (pendant)#*</td>
			<td>1 (2.7%)</td>
			<td>Yes</td>
			<td>1 positive</td>
			<td>1 negative</td>
		</tr>
		<tr>
			<td>Metal ball#</td>
			<td>1 (2.7%)</td>
			<td>Yes</td>
			<td>1 positive</td>
			<td>1 positive</td>
		</tr>
		<tr>
			<td>Plastic Button%</td>
			<td>1 (2.7%)</td>
			<td>No</td>
			<td>Not applicable</td>
			<td>1 negative</td>
		</tr>
		<tr>
			<td>Stapler pin#</td>
			<td>1 (2.7%)</td>
			<td>Yes</td>
			<td>1 negative</td>
			<td>1 negative</td>
		</tr>
		<tr>
			<td colspan="5">-&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; #&#160; metallic foreign bodies&#160;</td>
		</tr>
		<tr>
			<td colspan="5">-&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; * aluminium objects</td>
		</tr>
		<tr>
			<td colspan="5">-&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; %&#160; non-metallic foreign bodies</td>
		</tr>
	</tbody>
</table>
Table 1: Types of foreign bodies ingested. This table has been modified from Hamzah et al. 201820.

Watch this Scientific Journal Video about Handheld Metal Detector Screening for Metallic Foreign Body Ingestion in Children at JoVE.com

Handheld Metal Detector Screening for Metallic Foreign Body Ingestion in Children

Here, we present a protocol to use the handheld metal detector, to screen for the presence of ingested metallic foreign bodies in children who present to the pediatric emergency medicine department with a history of foreign body ingestion.

Coins are the most common ingested metallic foreign bodies among children. The goal of this protocol is to assess the accuracy and feasibility of using a ...

handheld-metal-detector-screening-for-metallic-foreign-body-ingestion

Nanyang Technological University

Research

JoVE Journal

Medicine

10.6K Views.  KK women's and Children's Hospital. Here, we present a protocol to use the handheld metal detector, to screen for the presence of ingested metallic foreign bodies in children who present to the pediatric emergency medicine department with a history of foreign body ingestion.

Video: Handheld Metal Detector Screening for Metallic Foreign Body Ingestion in Children

Dissection of Human Vitreous Body Elements for Proteomic Analysis

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions between vitreous substructures and the retina underlie several vitreoretinal diseases, including retinal tear and detachment, macular pucker, macular hole, age-related macular degeneration, vitreomacular traction, proliferative vitreoretinopathy, proliferative diabetic retinopathy, and inherited vitreoretinopathies. 1,2 The molecular composition of the vitreous substructures is not known. Since the vitreous body is transparent with limited surgical access, it has been difficult to study its substructures at the molecular level. We developed a method to separate and preserve these tissues for proteomic and biochemical analysis. The dissection technique in this experimental video shows how to isolate vitreous base, anterior hyaloid, vitreous core, and vitreous cortex from postmortem human eyes. One-dimensional SDS-PAGE analyses of each vitreous component showed that our dissection technique resulted in four unique protein profiles corresponding to each substructure of the human vitreous body. Identification of differentially compartmentalized proteins will reveal candidate molecules underlying various vitreoretinal diseases.

This video shows an effective technique for differentiating and dissecting the various semi-transparent structures of the human vitreous body in post mortem eyes.

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions ...

High Content Screening in Neurodegenerative Diseases

The functional annotation of genomes, construction of molecular networks and novel drug target identification, are important challenges that need to be addressed as a matter of great urgency1-4. Multiple complementary 'omics' approaches have provided clues as to the genetic risk factors and pathogenic mechanisms underlying numerous neurodegenerative diseases, but most findings still require functional validation5. For example, a recent genome wide association study for Parkinson's Disease (PD), identified many new loci as risk factors for the disease, but the underlying causative variant(s) or pathogenic mechanism is not known6, 7. As each associated region can contain several genes, the functional evaluation of each of the genes on phenotypes associated with the disease, using traditional cell biology techniques would take too long. 
	There is also a need to understand the molecular networks that link genetic mutations to the phenotypes they cause. It is expected that disease phenotypes are the result of multiple interactions that have been disrupted. Reconstruction of these networks using traditional molecular methods would be time consuming. Moreover, network predictions from independent studies of individual components, the reductionism approach, will probably underestimate the network complexity8. This underestimation could, in part, explain the low success rate of drug approval due to undesirable or toxic side effects. Gaining a network perspective of disease related pathways using HT/HC cellular screening approaches, and identifying key nodes within these pathways, could lead to the identification of targets that are more suited for therapeutic intervention.
	High-throughput screening (HTS) is an ideal methodology to address these issues9-12. but traditional methods were one dimensional whole-well cell assays, that used simplistic readouts for complex biological processes. They were unable to simultaneously quantify the many phenotypes observed in neurodegenerative diseases such as axonal transport deficits or alterations in morphology properties13, 14. This approach could not be used to investigate the dynamic nature of cellular processes or pathogenic events that occur in a subset of cells. To quantify such features one has to move to multi-dimensional phenotypes termed high-content screening (HCS)4, 15-17. HCS is the cell-based quantification of several processes simultaneously, which provides a more detailed representation of the cellular response to various perturbations compared to HTS. 
	HCS has many advantages over HTS18, 19, but conducting a high-throughput (HT)-high-content (HC) screen in neuronal models is problematic due to high cost, environmental variation and human error. In order to detect cellular responses on a 'phenomics' scale using HC imaging one has to reduce variation and error, while increasing sensitivity and reproducibility. 
	Herein we describe a method to accurately and reliably conduct shRNA screens using automated cell culturing20 and HC imaging in neuronal cellular models. We describe how we have used this methodology to identify modulators for one particular protein, DJ1, which when mutated causes autosomal recessive parkinsonism21. 
	Combining the versatility of HC imaging with HT methods, it is possible to accurately quantify a plethora of phenotypes. This could subsequently be utilized to advance our understanding of the genome, the pathways involved in disease pathogenesis as well as identify potential therapeutic targets.

We describe a methodology combining automated cell culturing with high-content imaging to visualize and quantify multiple cellular processes and structures, in a high-throughput manner. Such methods can aid in the further functional annotation of genomes as well as identify disease gene networks and potential drug targets.

The functional annotation of genomes, construction of molecular networks and novel drug target identification, are important challenges that need to be ...

Eye Tracking Young Children with Autism

The rise of accessible commercial eye-tracking systems has fueled a rapid increase in their use in psychological and psychiatric research. By providing a direct, detailed and objective measure of gaze behavior, eye-tracking has become a valuable tool for examining abnormal perceptual strategies in clinical populations and has been used to identify disorder-specific characteristics1, promote early identification2, and inform treatment3. In particular, investigators of autism spectrum disorders (ASD) have benefited from integrating eye-tracking into their research paradigms4-7. Eye-tracking has largely been used in these studies to reveal mechanisms underlying impaired task performance8 and abnormal brain functioning9, particularly during the processing of social information1,10-11. While older children and adults with ASD comprise the preponderance of research in this area, eye-tracking may be especially useful for studying young children with the disorder as it offers a non-invasive tool for assessing and quantifying early-emerging developmental abnormalities2,12-13. Implementing eye-tracking with young children with ASD, however, is associated with a number of unique challenges, including issues with compliant behavior resulting from specific task demands and disorder-related psychosocial considerations. In this protocol, we detail methodological considerations for optimizing research design, data acquisition and psychometric analysis while eye-tracking young children with ASD. The provided recommendations are also designed to be more broadly applicable for eye-tracking children with other developmental disabilities. By offering guidelines for best practices in these areas based upon lessons derived from our own work, we hope to help other investigators make sound research design and analysis choices while avoiding common pitfalls that can compromise data acquisition while eye-tracking young children with ASD or other developmental difficulties.

Eye tracking has long been used to study gaze patterns in typically-developing individuals, but recent technological advancements have made its use with clinical populations, including autism, more feasible. While eye-tracking young children with autism can offer insight into early symptom manifestations, it involves methodological challenges. Suggestions for best practices are provided.

The rise of accessible commercial eye-tracking systems has fueled a rapid increase in their use in psychological and psychiatric research. By providing a ...

Protocol for Long Duration Whole Body Hyperthermia in Mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

This paper describes a protocol for whole body hyperthermia in mice that can stimulate fever like conditions up to 12-24 hr.

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body ...

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children

The autonomic nervous system (ANS) controls mainly automatic bodily functions that are engaged in homeostasis, like heart rate, digestion, respiratory rate, salivation, perspiration and renal function. The ANS has two main branches: the sympathetic nervous system, preparing the human body for action in times of danger and stress, and the parasympathetic nervous system, which regulates the resting state of the body.
ANS activity can be measured invasively, for instance by radiotracer techniques or microelectrode recording from superficial nerves, or it can be measured non-invasively by using changes in an organ's response as a proxy for changes in ANS activity, for instance of the sweat glands or the heart. Invasive measurements have the highest validity but are very poorly feasible in large scale samples where non-invasive measures are the preferred approach. Autonomic effects on the heart can be reliably quantified by the recording of the electrocardiogram (ECG) in combination with the impedance cardiogram (ICG), which reflects the changes in thorax impedance in response to respiration and the ejection of blood from the ventricle into the aorta. From the respiration and ECG signals, respiratory sinus arrhythmia can be extracted as a measure of cardiac parasympathetic control. From the ECG and the left ventricular ejection signals, the preejection period can be extracted as a measure of cardiac sympathetic control. ECG and ICG recording is mostly done in laboratory settings. However, having the subjects report to a laboratory greatly reduces ecological validity, is not always doable in large scale epidemiological studies, and can be intimidating for young children. An ambulatory device for ECG and ICG simultaneously resolves these three problems.
Here, we present a study design for a minimally invasive and rapid assessment of cardiac autonomic control in children, using a validated ambulatory device 1-5, the VU University Ambulatory Monitoring System (VU-AMS, Amsterdam, the Netherlands,<a href="http://www.vu-ams.nl" target="_blank"> www.vu-ams.nl</a>).

Measuring Cardiac Autonomic Nervous System ANS Activity in Children

Measurement of autonomic nervous system activity usually confines the researcher and participant to the laboratory, which may provide an intimidating environment to children. The VU University Ambulatory Monitoring System (VU-AMS) device can record cardiac autonomic control in any setting. The VU-AMS proved very amenable to testing in children.

The autonomic nervous system (ANS) controls mainly automatic bodily functions that are engaged in homeostasis, like heart rate, digestion, respiratory ...

Screening for Melanoma Modifiers using a Zebrafish Autochthonous Tumor Model

Genomic studies of human cancers have yielded a wealth of information about genes that are altered in tumors1,2,3. A challenge arising from these studies is that many genes are altered, and it can be difficult to distinguish genetic alterations that drove tumorigenesis from that those arose incidentally during transformation. To draw this distinction it is beneficial to have an assay that can quantitatively measure the effect of an altered gene on tumor initiation and other processes that enable tumors to persist and disseminate. Here we present a rapid means to screen large numbers of candidate melanoma modifiers in zebrafish using an autochthonous tumor model4 that encompasses steps required for melanoma initiation and maintenance. A key reagent in this assay is the miniCoopR vector, which couples a wild-type copy of the mitfa melanocyte specification factor to a Gateway recombination cassette into which candidate melanoma genes can be recombined5. The miniCoopR vector has a mitfa rescuing minigene which contains the promoter, open reading frame and 3'-untranslated region of the wild-type mitfa gene. It allows us to make constructs using full-length open reading frames of candidate melanoma modifiers. These individual clones can then be injected into single cell Tg(mitfa:BRAFV600E);p53(lf);mitfa(lf)zebrafish embryos. The miniCoopR vector gets integrated by Tol2-mediated transgenesis6 and rescues melanocytes. Because they are physically coupled to the mitfa rescuing minigene, candidate genes are expressed in rescued melanocytes, some of which will transform and develop into tumors. The effect of a candidate gene on melanoma initiation and melanoma cell properties can be measured using melanoma-free survival curves, invasion assays, antibody staining and transplantation assays.

A rapid way to screen for melanoma modifiers using a zebrafish autochthonous tumor model is presented. It takes advantage of the miniCoopR vector which allows for expression of candidate melanoma genes in melanocytes. A method to obtain melanoma-free survival curves, an invasion assay, a protocol for antibody staining of scale melanocytes and a melanoma transplantation assay are described.

Genomic studies of  human cancers have yielded a wealth of information about genes that are altered  in tumors1,2,3. A challenge arising from these ...

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone resorption. Osteoclasts can be generated in vitro from monocyte/macrophage precursor cells in the presence of certain cytokines, which promote survival and differentiation. Here, both in vivo and in vitro techniques are demonstrated, which allow scientists to study different cytokine contributions towards osteoclast differentiation, signaling, and activation. The minicircle DNA delivery gene transfer system provides an alternative method to establish an osteoporosis-related model is particularly useful to study the efficacy of various pharmacological inhibitors in vivo. Similarly, in vitro culturing protocols for producing osteoclasts from human precursor cells in the presence of specific cytokines enables scientists to study osteoclastogenesis in human cells for translational applications. Combined, these techniques have the potential to accelerate drug discovery efforts for osteoclast-specific targeted therapeutics, which may benefit millions of osteoporosis and arthritis patients worldwide.

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation of precursor cells into osteoclasts is regulated by cytokines and growth factors. Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described.

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone ...

Calibrated Forceps Model of Spinal Cord Compression Injury

Compression injuries of the murine spinal cord are valuable animal models for the study of spinal cord injury (SCI) and spinal regenerative therapy. The calibrated forceps model of compression injury is a convenient, low cost, and very reproducible animal model for SCI. We used a pair of modified forceps in accordance with the method published by Plemel et al. (2008) to laterally compress the spinal cord to a distance of 0.35 mm. In this video, we will demonstrate a dorsal laminectomy to expose the spinal cord, followed by compression of the spinal cord with the modified forceps. In the video, we will also address issues related to the care of paraplegic laboratory animals. This injury model produces mice that exhibit impairment in sensation, as well as impaired hindlimb locomotor function. Furthermore, this method of injury produces consistent aberrations in the pathology of the SCI, as determined by immunohistochemical methods. After watching this video, viewers should be able to determine the necessary supplies and methods for producing SCI of various severities in the mouse for studies on SCI and/or treatments designed to mitigate impairment after injury.

Spinal cord injury models should be highly reproducible. We demonstrate that the calibrated forceps compression model of spinal cord injury is an easy to use surgical method for generating reproducible injuries to the murine spinal cord.

Compression injuries of the murine spinal cord are valuable animal models for the study of spinal cord injury (SCI) and spinal regenerative therapy. The ...

Normothermic Ex Vivo Kidney Perfusion for the Preservation of Kidney Grafts prior to Transplantation

Kidney transplantation has become a well-established treatment option for patients with end-stage renal failure. The persisting organ shortage remains a serious problem. Therefore, the acceptance criteria for organ donors have been extended leading to the usage of marginal kidney grafts. These marginal organs tolerate cold storage poorly resulting in increased preservation injury and higher rates of delayed graft function. To overcome the limitations of cold storage, extensive research is focused on alternative normothermic preservation methods.
Ex vivo normothermic organ perfusion is an innovative preservation technique. The first experimental and clinical trials for ex vivo lung, liver, and kidney perfusions demonstrated favorable outcomes.
In addition to the reduction of cold ischemic injury, the method of normothermic kidney storage offers the opportunity for organ assessment and repair. This manuscript provides information about kidney retrieval, organ preservation techniques, and isolated ex vivo normothermic kidney perfusion (NEVKP) in a porcine model. Surgical techniques, set up for the perfusion solution and the circuit, potential assessment options, and representative results are demonstrated.

Normothermic Ex Vivo Kidney Perfusion for the Preservation of Kidney Grafts prior to Transplantation

The severe organ shortage has resulted in increased use of marginal kidney grafts for transplantation. This has triggered interest in alternative storage methods, since marginal grafts especially tolerate cold storage poorly. The technique of normothermic ex vivo kidney perfusion (NEVKP) represents a novel preservation method for kidney grafts prior to &#160;transplantation.

Kidney transplantation has become a well-established treatment option for patients with end-stage renal failure. The persisting organ shortage remains a ...

Heterotopic Renal Autotransplantation in a Porcine Model: A Step-by-Step Protocol

Kidney transplantation is the treatment of choice for patients suffering from end-stage renal disease. It offers better life expectancy and higher quality of life when compared to dialysis. Although the last few decades have seen major improvements in patient outcomes following kidney transplantation, the increasing shortage of available organs represents a severe problem worldwide. To expand the donor pool, marginal kidney grafts recovered from extended criteria donors (ECD) or donated after circulatory death (DCD) are now accepted for transplantation. To further improve the postoperative outcome of these marginal grafts, research must focus on new therapeutic approaches such as alternative preservation techniques, immunomodulation, gene transfer, and stem cell administration.
Experimental studies in animal models are the final step before newly developed techniques can be translated into clinical practice. Porcine kidney transplantation is an excellent model of human transplantation and allows investigation of novel approaches. The major advantage of the porcine model is its anatomical and physiological similarity to the human body, which facilitates the rapid translation of new findings to clinical trials. This article offers a surgical step-by-step protocol for an autotransplantation model and highlights key factors to ensure experimental success. Adequate pre- and postoperative housing, attentive anesthesia, and consistent surgical techniques result in favorable postoperative outcomes. Resection of the contralateral native kidney provides the opportunity to assess post-transplant graft function. The placement of venous and urinary catheters and the use of metabolic cages allow further detailed evaluation. For long-term follow-up studies and investigation of alternative graft preservation techniques, autotransplantation models are superior to allotransplantation models, as they avoid the confounding bias posed by rejection and immunosuppressive medication.

Porcine models of organ transplantation provide an important platform to study mechanisms of organ preservation. This article describes a heterotopic porcine renal autotransplantation model, which allows investigating new approaches to improve the outcome of transplantation using marginal kidney grafts.

Kidney transplantation is the treatment of choice for patients suffering from end-stage renal disease. It offers better life expectancy and higher quality ...

Handheld Metal Detector Screening for Metallic Foreign Body Ingestion in Children

Summary

Explore More Videos

Chapters in this video

Dissection of Human Vitreous Body Elements for Proteomic Analysis

High Content Screening in Neurodegenerative Diseases

Eye Tracking Young Children with Autism

Protocol for Long Duration Whole Body Hyperthermia in Mice

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children

Screening for Melanoma Modifiers using a Zebrafish Autochthonous Tumor Model

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Calibrated Forceps Model of Spinal Cord Compression Injury

Normothermic Ex Vivo Kidney Perfusion for the Preservation of Kidney Grafts prior to Transplantation

Heterotopic Renal Autotransplantation in a Porcine Model: A Step-by-Step Protocol