This paper is supported in part by the James V. Bastek, M.D. Hereditary Retinal Disease Research Program, Bascom Palmer Eye Institute, University of Miami, FL, USA; NIH Center Core Grant P30EY014801; Research to Prevent Blindness Unrestricted Award and Career Development Awards; Florida Lions Eye Bank and the Beauty of Sight Foundation, Miami, FL, USA; and Henri and Flore Lesieur Foundation.

The protocol follows the operating room guidelines of the Bascom Palmer Eye Institute, University of Miami and is applicable to infants, young children, and uncooperative adults. Patients who cannot have general anesthesia due to safety issues should not have the procedure.
1. Operating room selection and modification
<ol>
	<li>Select an operating room with low 60 Hz background electric current noise and proper electrical grounding, to avoid ERG recording interference. Use a room with an isolated electrical circuit without connection to or is near heavy appliances (e.g., refrigerator).
	<ol>
		<li>Perform trial ERG recordings in the operating room at the location where the ERG recording will take place. Check the ERG recording baseline as well as the trial recording waveforms to determine the absence of 60 Hz background electric noise.</li>
	</ol>
	</li>
	<li>Inspect the operating room for light leaks from ceiling, door, and window openings. Perform human observation after full dark adaptation (30 to 45 minutes) given that the normal human eye can detect light as dim as approximately 4 photons, which is better than any man-made light meter except liquid nitrogen-cooled detectors for astronomy.</li>
	<li>Install opaque non-reflective black curtains on tracks to cover the operating room door and window openings fully without light leakage (Figure 1). Select curtain material that is washable and resistant to staining and bacterial growth. Follow local operating room regulations and procedures for proper interval cleaning. Block light leaks from the ceiling if present.</li>
</ol>
2. Foldable portable darkroom selection and modification
<ol>
	<li>Select a portable darkroom that is easy to install and store and large enough to enclose the patient&#8217;s head, the ERG examiner, and the ffERG stimulus. Use folding portable darkrooms designed for an optic physicist (e.g., www.scientex.co.jp/pdf/pdf-b-lp-eng.pdf, 48&#8221;x 48&#8221;x81&#8221; cross type) which are available commercially and optimizes the maintenance of retinal dark adaptation of the patient during scotopic ffERG recordings (Figure 2). 
	NOTE: The fabric of the portable darkroom mentioned was tested by the eye institute&#8217;s microbiology department for ease of disinfection and the optical transmission was tested by the eye institute&#8217;s biomedical department before purchase. This is recommended if a different portable darkroom is used.</li>
	<li>Add a small opening with double flaps at the rear of the portable darkroom to allow routing connections and cables (Figure 3). 
	NOTE: During scotopic ffERG testing, the ffERG light stimulus is inside the folding portable darkroom and the ERG recording system is outside of the portable darkroom. The ERG electrode wire connections and the cable connecting the ERG light stimulus to the ERG recording system go through the opening created with a double closure system to ensure total darkness. We use a small handheld ffERG light stimulus to ease ERG recording inside the folding portable darkroom and record one eye at a time. A larger ffERG light stimulus can record both eyes simultaneous but will need to be held by a metallic arm requiring a larger opening at the rear of the portable darkroom and will likely require a larger darkroom.</li>
</ol>
3. Patient preparation and retinal dark adaption
<ol>
	<li>Confirm medical reason for ffERG and obtain informed consent for examination under anesthesia, ffERG, and other procedures of interest for patient management such as retinal imaging (e.g., fundus imaging, optical coherence tomography, fluorescein angiography) and venopuncture for genetic testing. 
	NOTE: Most common reasons for ffERG in infants and young children include decreased vision, nystagmus, nyctalopia, visual photosensitivity, abnormal fundus, and medication with risk of retinal toxicity (e.g., vigabatrin). Important to recognize factors that are likely to affect ERG recordings including high myopia and albinism. In general, ffERG responses from infants younger than age 6 months are small and still developing, making interpretation of recorded responses difficult.</li>
	<li>Place ocular anesthetic drop (proparacaine 0.5%) followed by pupillary dilation combo drop (cyclopentolate 1% + phenylnephreine 0.5%) to each eye. Repeat the combo drop to each eye 2 to 3 times with 5 minutes between drops. 
	NOTE: The proparacaine decreases burning sensation and increases corneal absorption of the dilating drops but may have to be skipped in patients with very poor cooperation.</li>
	<li>Patch both eyes for retinal dark adaptation of at least 30 minutes. With eyelids gently and completely closed, place 2 regular-size self-adhesive eye occlusion patches over each eye without significant pressure on the eye.
	<ol>
		<li>Place the first patch conventionally and oriented horizontally with the wider end of the patch temporally. Place the second patch horizontally over the first patch with the wider end nasally and adjust the position typically with a tilt counterclockwise to prevent light leak nasally.</li>
	</ol>
	</li>
	<li>After placing the eye patches over each eye, place opaque black tape horizontally across to cover both eyes without significant pressure on the eyes. Make a small vertical cut at the inferior edge of the black tape before placement at the location across the bridge of the nose to avoid pressure on the nose.</li>
	<li>Place the black opaque relaxation sleeping mask with head headband over the patched eyes (Figure 4). 
	NOTE: ISCEV international standard for dark adaptation is 20 minutes. Dark adaptation of at least 30 minutes is preferred to facilitate optimal scotopic ffERG recording given the retinal dark adaptation curve reaches a more asymptotic point compared to 20 minutes. Based on our experience, vast majority of infant and young children are tolerant of bilateral patching, and parental support and encouragement are critical. Explaining the purpose of dark adaptation and the benefit of reducing general anesthesia time helps the parents to understand. Parental tender loving care including cuddling, music from cell phone, and pacifier are very helpful during the dark adaptation period. Of over 120 infants and young children who underwent the method, only 2 patients could not tolerate bilateral patching for dark adaptation. Both patients were dark-adapted after general anesthesia induction instead and the ERG responses were subsequently successfully recorded using the same method.</li>
</ol>
4. Dark-Adapted full-field electroretinogram recording in the operating room
<ol>
	<li>Prepare the operating room by placing translucent red filter films over monitors and opaque black tape over LEDs and light sources (Figure 5A-5B). Set up folding portable darkroom. Close curtains over door and window openings.</li>
	<li>Induce general anesthesia or sedation by anesthesiology team on bilaterally-patched patient followed by continued anesthesiology monitoring. Perform timeout to verify procedures to be performed.</li>
	<li>Place ERG recording electrodes, ffERG light stimulus, a very dim red light mounted on a forehead band, topical 0.5% ophthalmic proparacaine, 2.5% ophthalmic hydroxypropyl methylcellulose (if Burian-Allen electrode is used), and sterile gauze (for wiping excess methylcellulose) close to ERG examiner position before placing the portable darkroom to enclose the head of the patient and ERG examiner (Figure 6A). The ERG examiner will be using the mounted red forehead band to perform scotopic ffERG recordings. 
	NOTE: The red light mounted on a forehead band is modified by placing layers of red light filter films over the LEDs. The red light should be as dim as possible to allow the ERG examiner to perform the procedure so dark adaptation is maintained. Helpful for the examiner to wait a few minutes to have some of his or her own partial dark adaptation before placing the electrodes. Experienced ERG examiners tend to use very dim red light or can do the procedure by feel without any red light if Burian-Allen electrode is used.</li>
	<li>Place the ground ERG electrode clip with conductive paste on one ear lobe. Snake the ground ERG electrode connection and ffERG light stimulus cable through the modified flap opening of the portable darkroom and the ERG technician connects them to the ERG system outside of the darkroom.</li>
	<li>Close the front opening of the portable darkroom with large binder clips. Turn off room lights and check and cover any remaining uncovered light sources with black tape.</li>
	<li>Remove the black mask over both eyes. Remove the black tape and patches over the right eye only and place the corneal ERG recording electrode on the right eye to record the scotopic ffERG responses using the hand-held full-field light stimulus in accordance to the ISCEV standards (Figure 6B).
	<ol>
		<li>Snake the ERG recording electrode connection through the modified flap opening of the portable darkroom for the ERG technician to connect it to the ERG system outside of the darkroom. Take care to use the dimmest red light possible, and a brief period of additional dark adaptation, approximately 5 min, is recommended for recovery after lens insertion in accordance to the ISCEV standards.</li>
		<li>After checking for electrical baseline stability and ERG electrode impedance, proceed with recording of the rod responses (dark-adapted 0.01 cd&#183;s&#183;m-2 flash ERG), followed by the combined rod-cone responses (dark-adapted 3.0 cd&#183;s&#183;m-2 flash ERG and 10 cd&#183;s&#183;m-2 flash ERG) and the dark-adapted 3.0 flash oscillatory potential responses. Be mindful of the recommended time intervals between the light stimulus to maintain dark adaptation. 
		NOTE: When a handheld ERG light stimulus is used to test one eye at a time, keep the other eye monocular patched to maintain dark adaptation during scotopic recordings of the first eye. Dawson Trick Litzkow (DTL) fiber electrode or bipolar Burian-Allen ERG corneal electrodes are typically used. The DTL electrode is better tolerated by a conscious patient and has lower amplitude-to-noise ratio compared to the Burian-Allen ERG corneal electrode. Given patient tolerance is not an issue during sedation or general anesthesia, Burian-Allen electrode is preferred for sedated ERG recordings given its superior amplitude-to-noise ratio.</li>
	</ol>
	</li>
	<li>Remove the black tape and patches of the left eye and proceed with scotopic ffERG recording of the left eye following same procedures as for the first eye as in step 4.6 with the hand-held full-field light stimulus. 
	NOTE: Recorded scotopic ffERG amplitudes tend to be mildly lower in the second recorded eye given the retinal dark adaptation of the second eye is typically affected by the ERG stimulus flashes diffusing to the eye through bone and tissue during ERG recording of the first eye.</li>
</ol>
5. Light-Adapted full-field electroretinogram recording in the operating room
<ol>
	<li>After completion of the scotopic ffERG recordings, turn on all overhead room lights. Disconnect the ERG electrode connections and the ffERG light stimulus cable from the ERG recording system and snake them back to the inside the portable dark room through the modified flap opening. Remove the portable dark room.</li>
	<li>Light adapt both eyes for 10 minutes by using the overhead room lights in accordance to the ISCEV standards (background luminance 30 cd&#183;m-2). Keep the bipolar Burian-Allen ERG electrodes in place for both eyes given the built-in eyelid speculums of the electrodes will hold the eyes open. If DTL lenses are used, use eyelid speculums to keep both eyes open with instillation of periodic lubricating eye drops to avoid corneal drying.</li>
	<li>Connect the ERG electrode connections and the ffERG light stimulus cable to the ERG system and proceed to record, in accordance to the ISCEV standards, the cone flash responses (light-adapted 3.0 cd&#183;s&#183;m-2 flash ERG) followed by the cone flicker responses (light-adapted 3.0 flicker ERG). 
	NOTE: This completes the ffERG recording. Other diagnostic retinal imaging including OCT, fundus photos as well as venopuncture for genetic testing can easily follow while the patient remains sedated.</li>
</ol>

<ol>
	<li>McCulloch, D. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ISCEV+Standard+for+full-field+clinical+electroretinography+(2015+update).">ISCEV Standard for full-field clinical electroretinography (2015 update).</a> Documenta Ophthalmologica. 130 (1), 1-12 (2015).</li><li>Robson, A. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ISCEV+guide+to+visual+electrodiagnostic+procedures.">ISCEV guide to visual electrodiagnostic procedures.</a> Documenta Ophthalmologica. 136 (1), 1-26 (2018).</li><li>Holder, G. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=International+Federation+of+Clinical+Neurophysiology:+recommendations+for+visual+system+testing.">International Federation of Clinical Neurophysiology: recommendations for visual system testing.</a> Clinical Neurophysiology. 121 (9), 1393-1409 (2010).</li><li>Fulton, A. B., Hartmann, E. E., Hansen, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiologic+testing+techniques+for+children.">Electrophysiologic testing techniques for children.</a> Documenta Ophthalmologica. 71 (4), 341-354 (1989).</li><li>van Genderen, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+key+role+of+electrophysiology+in+the+diagnosis+of+visually+impaired+children.">The key role of electrophysiology in the diagnosis of visually impaired children.</a> Acta Ophthalmologica Scandinavica. 84 (6), 799-806 (2006).</li><li>Lalwani, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+'dark'+side+of+sedation:+12+years+of+office-based+pediatric+deep+sedation+for+electroretinography+in+the+dark.">The 'dark' side of sedation: 12 years of office-based pediatric deep sedation for electroretinography in the dark.</a> Pediatric Anesthesia. 21 (1), 65-71 (2011).</li><li>Guidelines, ICfPCE, et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pediatric+clinical+visual+electrophysiology:+a+survey+of+actual+practice.">Pediatric clinical visual electrophysiology: a survey of actual practice.</a> Documenta Ophthalmologica. 113 (3), 193-204 (2006).</li><li>Wongpichedchai, S., Hansen, R. M., Koka, B., Gudas, V. M., Fulton, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+halothane+on+children's+electroretinograms.">Effects of halothane on children's electroretinograms.</a> Ophthalmology. 99 (8), 1309-1312 (1992).</li><li>Andreasson, S., Tornqvist, K., Ehinger, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full-field+electroretinograms+during+general+anesthesia+in+normal+children+compared+to+examination+with+topical+anesthesia.">Full-field electroretinograms during general anesthesia in normal children compared to examination with topical anesthesia.</a> Acta Ophthalmologica (Copenhagen). 71 (4), 491-495 (1993).</li><li>Brigell, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guidelines+for+calibration+of+stimulus+and+recording+parameters+used+in+clinical+electrophysiology+of+vision.">Guidelines for calibration of stimulus and recording parameters used in clinical electrophysiology of vision.</a> Documenta Ophthalmologica. 107 (2), 185-193 (2003).</li></ol>

The authors have nothing to disclose.

The methodology and protocol describe how to effectively perform valid and reliable ffERG in infants and children under sedation or general anesthesia in the operating room. The major concept and aim of the technique are to provide and maintain optimal retinal dark adaptation during scotopic ffERG recordings. This is essential to provide accurate objective assessment of rod photoreceptor function given retinal dark adaptation is rapidly diminished by exposure even to dim light leading to erroneous recorded responses. The...

The electroretinogram (ERG) is the only clinical objective test available to assess retinal function and the full-field ERG (ffERG) is the only objective test to assess rod-photoreceptor generated activities1,2. The ffERG measures the electrical responses from the entire retina elicited by a full-field flash stimulus and is a gold standard test in the diagnosis and management of inherited retinal diseases2,3. Thus, the ffERG is an important test in infants and young children to detect early onset inherited retinal diseases such as Leber congenital amaurosis where approved gene therapy and clinical trials are available4,5.
Adherence to ffERG standards established by the International Society for Clinical Electrophysiology of Vision (ISCEV) are critical to acquire valid and reliable dark-adapted (scotopic) and light-adapted (photopic) ffERG responses1,3. Failure to properly maintain adequate retinal dark adaptation during scotopic ffERG recordings results in falsely-impaired recorded responses and patient mismanagement. Performing ffERG in infants and children is challenging given limited cooperation and often requires general anesthesia in the operating room6. A recent survey among ISCEV members showed 12-14% of ERG&#8217;s are performed under sedation or general anesthesia7. Maintaining retinal dark adaptation in the operating room is difficult given the numerous light sources from anesthesiology monitoring systems and other equipment. While anesthetic agents may have an effect in reducing ERG responses, ERG responses under sedation or general anesthesia are reliable in providing accurate diagnosis6,8,9.
A simple and widely applicable method is described for ffERG testing in the operating room that adheres to the international standards and optimizes retinal dark adaptation. The goal of this practical method is to provide valid reliable scotopic and photopic ffERG recordings to assess objective retinal function in infants and young children, which is particularly relevant in this young age group given subjective assessment of visual function such as visual acuity and visual fields are typically not possible. The operating room is modified to promote retinal dark adaptation, and the procedures reduce operating room time by dark-adapting the patient before sedation or general anesthesiology is instituted. A modified portable foldable darkroom encloses the patient&#8217;s head and the ERG examiner during ffERG scotopic recordings to minimize any remaining light source including light emission from the ERG system. The portable darkroom allows rapid access to the patient by the anesthesiologist when necessary. After the completion of ffERG, diagnostic retinal imaging including optical coherence tomography (OCT) and fundus imaging as well as venopuncture for genetic testing can easily be performed while the patient remains under anesthesia.
The method is suitable for practitioners and practices that manage pediatric patients with retinopathies. An average sized ocular operating room provides adequate space, and a room with low background electrical noise is desirable to allow quality ffERG recording. While the ERG examiner is inside the foldable darkroom during scotopic ffERG recording, a trained technician is needed to operate the ERG system outside of the foldable darkroom. Conferring with the anesthesiology team is essential in modifying the operating room and to promote the safety of the patient in a darkened environment.
The advantages of the method over alternative techniques include optimizing and maintaining retinal dark adaptation, promoting valid reliable ffERG recordings, improving patient safety, and facilitating additional diagnostic testing such as retinal imaging and venopuncture for genetic testing. Optimal dark adaptation is also critical given ffERG stimulators should be calibrated for complete darkness conditions as recommended by ISCEV10. Alternative methods include the use of oral agents such as chloral hydrate with variable sedative responses in infants and children, which affects the quality of ffERG recordings and causes difficulties in monitoring vital signs. While some children can cooperate with ffERG recording in the clinic, the testing session may be prolonged depending on cooperation, and the validity of ffERG recordings may be affected by eye movement and blink artifacts as well as difficulty in maintainng retinal dark adaptation4. The current method provides additional dark adaptation and safety measures compared to the previously described deep sedation ffERG method6.

<table>
	<tbody>
		<tr>
			<td>Black tape</td>
			<td>3M Industrial Adhesives and Tapes Division, St Paul, MN 55144-1000 USA</td>
			<td>3M ID 70016070396</td>
			<td></td>
		</tr>
		<tr>
			<td>Conduction and abrasive paste</td>
			<td>Redux Paste (Electrolyte Paste) Hewlett Packard company, USA. Nuprep (Sking Prep Gel) and Ten20 (Conductive Neurodiagnostic Electrode Paste) Weaver and Company, CO, USA</td>
			<td>67-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Darkroom - Portable foldable</td>
			<td>Scientex</td>
			<td>B-LP1/B-LP1-X</td>
			<td>Available in different sizes</td>
		</tr>
		<tr>
			<td>Dark adaptation mask (relaxation sleeping mask)</td>
			<td>Mindfold Inc, Durango, CO, USA</td>
			<td>6576493</td>
			<td>Flexible black plastic face plate backed with a high-density soft foam padding that allows total darkness.</td>
		</tr>
		<tr>
			<td>Ear clips for electric grounding</td>
			<td>Grass</td>
			<td>F-E34DG-72</td>
			<td>Grass 10mm Gold Cup EEG Ear Clip with touchproof connector 72&#34; wire - Set of 2</td>
		</tr>
		<tr>
			<td>Electrodes ERG recording (Burian-Allen, DTL)</td>
			<td>Burian-Allen, Hansen Ophthalmic Develoment Lab, Iowa, USA; DTL, Diagnosys, Lowell, MA 01854, USA.</td>
			<td>303-20LA, 303-20A, 303-20P, 303-20I, 303-20SI</td>
			<td>Available in different sizes, requires modification as described in Protocol.</td>
		</tr>
		<tr>
			<td>ERG systems including handheld full-field stimulus</td>
			<td>Any system meeting the standards established by the International Society for Clinical Electrophysiology of Vision (ISCEV).</td>
			<td></td>
			<td>Authors use Diagnosys and Roland systems; other ISCEV standard systems available.</td>
		</tr>
		<tr>
			<td>Eye drops, propracaine, metilcellulose, phenilephrine, ciclopentolate,</td>
			<td>Tropicamide 1% Phenylephrine 2.5% Cyclopentolate 1% Proparacaine 0.5% Akorn, Inc. Forest, IL 60045 GONIOTAIRE (Hypromellose 2.5%) Altaire Pharmaceuticals, Inc. NY, NY, USA 11931</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Eye Patch</td>
			<td>BSN Medical Inc, Rutherford College, NC</td>
			<td>46430-00</td>
			<td>Coverlet eye occlusor for treatment of lazy eye</td>
		</tr>
		<tr>
			<td>Head band with light</td>
			<td>REMIX PRO. Princeton Tec, 
			Trenton, NJ 08650</td>
			<td>RMX300PRO-RD-BK</td>
			<td>Requires placing layers of red filters over LED as described in protocol</td>
		</tr>
	</tbody>
</table>

electroretinogram recording for infants and children under anesthesia to achieve optimal dark adaptation and international standards

Electroretinogram (ERG) is the only clinical objective test available to assess retinal function. Full-field ERG (ffERG) measures the panretinal rod and cone photoreceptor function as well as inner retinal function and is an important measure in the diagnosis and management of inherited retinal diseases as well as inflammatory, toxic, and nutritional retinopathies. Adhering to international standards and maintaining retinal dark adaptation are critical to acquire valid and reliable dark-adapted (scotopic) and light-adapted (photopic) ffERG responses. Performing ffERG in infants and children is challenging and often requires general anesthesia in the operating room. However, maintaining retinal dark adaptation in the operating room is becoming increasingly difficult given the numerous light sources from anesthesiology monitoring systems and other equipment. A practical and widely applicable method for ffERG testing is described in the operating room that optimizes retinal dark adaptation. The method reduces operating room time by dark-adapting the patient before general anesthesiology is instituted. The operating room is modified for dark adaptation and any remaining light source in the darkened operating room is minimized with the use of a modified portable foldable darkroom that encloses the patient&#8217;s head and the ERG examiner during ffERG scotopic recordings. The simple method adheres to ffERG international standards and provides valid reliable scotopic and photopic ffERG recordings that are critical to assess objective retinal function in this young age group where subjective assessment of visual function such as visual acuity and visual fields are not possible. Furthermore, the ffERG is the gold standard clinical test in detecting early onset inherited retinal diseases including Leber congenital amaurosis where approved gene therapy has become available. In sedated conditions, very low amplitude ffERG signals can be detected due to minimal orbicularis muscle activity interference, which is particularly relevant in patients after gene therapy to detect improved amplitude responses.

Using the method described, valid, reliable, interpretable normal and abnormal ffERG responses are feasibly obtained in the operating room for infants and young children under sedation or general anesthesia. In particular, falsely low scotopic ffERG responses are avoided, and common retinal causes of decreased vision and nystagmus in this age group are readily identified. For instance, the preservation of scotopic ffERG responses is important to differentiate Leber congenital amaurosis from achromatopsia where the cone f...

Watch this Scientific Journal Video about Electroretinogram Recording for Infants and Children under Anesthesia to Achieve Optimal Dark Adaptation and International Standards at JoVE.com

Electroretinogram Recording for Infants and Children under Anesthesia to Achieve Optimal Dark Adaptation and International Standards

Adhering to international standards and maintaining retinal dark adaptation are critical to acquire valid full-field electroretinogram responses in the diagnosis and management of inherited retinal diseases. A practical protocol using a portable darkroom is provided to obtain full-field&#160;electroretinogram for infants and children under sedation or general anesthesia in the operating room setting.

Electroretinogram (ERG) is the only clinical objective test available to assess retinal function. Full-field ERG (ffERG) measures the panretinal rod and ...

electroretinogram-recording-for-infants-children-under-anesthesia-to

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Medicine

5.9K Views.  University of Miami Miller School of Medicine. Adhering to international standards and maintaining retinal dark adaptation are critical to acquire valid full-field electroretinogram responses in the diagnosis and management of inherited retinal diseases. A practical protocol using a portable darkroom is provided to obtain full-field electroretinogram for infants and children under sedation or general anesthesia in the operating room setting.

Video: Electroretinogram Recording for Infants and Children under Anesthesia to Achieve Optimal Dark Adaptation and International Standards

A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation

We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which works especially well with poor mask fit.
Can not intubate, can not ventilate" (CICV) is a potentially life threatening situation. In this video we present a simulation of the technique we used in a case of CICV where oxygenation and ventilation were maintained by inserting an endotracheal tube (ETT) nasally down to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.
A 13 year old patient was taken to the operating room for incision and drainage of a neck abcess and direct laryngobronchoscopy. After preoxygenation, anesthesia was induced intravenously. Mask ventilation was found to be extremely difficult because of the swelling of the soft tissue. The face mask could not fit properly on the face due to significant facial swelling as well. A direct laryngoscopy was attempted with no visualization of the larynx. Oxygen saturation was difficult to maintain, with saturations falling to 80%. In order to oxygenate and ventilate the patient, an endotracheal tube was then inserted nasally after nasal spray with nasal decongestant and lubricant. The tube was pushed gently and blindly into the hypopharynx. The mouth and nose of the patient were sealed by hand and positive pressure ventilation was possible with 100% O2 with good oxygen saturation during that period of time. Once the patient was stable and well sedated, a rigid bronchoscope was introduced by the otolaryngologist showing extensive subglottic and epiglottic edema, and a mass effect from the abscess, contributing to the airway compromise. The airway was secured with an ETT tube by the otolaryngologist.This video will show a simulation of the technique on a patient undergoing general anesthesia for dental restorations.

We describe a technique to maintain oxygenation and ventilation using an endotracheal tube inserted nasally to the level of the naso-pharynx while sealing the mouth and nares for successful positive pressure ventilation.

We describe a novel non surgical technique to maintain oxygenation and ventilation in a case of difficult intubation and difficult ventilation, which ...

Using Visual and Narrative Methods to Achieve Fair Process in Clinical Care

The Institute of Medicine has targeted patient-centeredness as an important area of quality improvement. A major dimension of patient-centeredness is respect for patient's values, preferences, and expressed needs. Yet specific approaches to gaining this understanding and translating it to quality care in the clinical setting are lacking. From a patient perspective quality is not a simple concept but is best understood in terms of five dimensions: technical outcomes; decision-making efficiency; amenities and convenience; information and emotional support; and overall patient satisfaction. Failure to consider quality from this five-pronged perspective results in a focus on medical outcomes, without considering the processes central to quality from the patient's perspective and vital to achieving good outcomes. In this paper, we argue for applying the concept of fair process in clinical settings. Fair process involves using a collaborative approach to exploring diagnostic issues and treatments with patients, explaining the rationale for decisions, setting expectations about roles and responsibilities, and implementing a core plan and ongoing evaluation. Fair process opens the door to bringing patient expertise into the clinical setting and the work of developing health care goals and strategies. This paper provides a step by step illustration of an innovative visual approach, called photovoice or photo-elicitation, to achieve fair process in clinical work with acquired brain injury survivors and others living with chronic health conditions. Applying this visual tool and methodology in the clinical setting will enhance patient-provider communication; engage patients as partners in identifying challenges, strengths, goals, and strategies; and support evaluation of progress over time. Asking patients to bring visuals of their lives into the clinical interaction can help to illuminate gaps in clinical knowledge, forge better therapeutic relationships with patients living with chronic conditions such as brain injury, and identify patient-centered goals and possibilities for healing. The process illustrated here can be used by clinicians, (primary care physicians, rehabilitation therapists, neurologists, neuropsychologists, psychologists, and others) working with people living with chronic conditions such as acquired brain injury, mental illness, physical disabilities, HIV/AIDS, substance abuse, or post-traumatic stress, and by leaders of support groups for the types of patients described above and their family members or caregivers.

This paper illustrates an innovative visual approach (photovoice or photo-elicitation) to achieve fair process in clinical care for patients living with chronic health conditions, illuminate gaps in clinical knowledge, forge better therapeutic relationships, and identify patient-centered goals and possibilities for healing.

The Institute of Medicine has targeted patient-centeredness as an important area of quality improvement. A major dimension of patient-centeredness is ...

Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants

Perinatal brain injury remains a significant cause of infant mortality and morbidity, but there is not yet an effective bedside tool that can accurately screen for brain injury, monitor injury evolution, or assess response to therapy. The energy used by neurons is derived largely from tissue oxidative metabolism, and neural hyperactivity and cell death are reflected by corresponding changes in cerebral oxygen metabolism (CMRO2). Thus, measures of CMRO2 are reflective of neuronal viability and provide critical diagnostic information, making CMRO2 an ideal target for bedside measurement of brain health.
Brain-imaging techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) yield measures of cerebral glucose and oxygen metabolism, but these techniques require the administration of radionucleotides, so they are used in only the most acute cases.
Continuous-wave near-infrared spectroscopy (CWNIRS) provides non-invasive and non-ionizing radiation measures of hemoglobin oxygen saturation (SO2) as a surrogate for cerebral oxygen consumption. However, SO2 is less than ideal as a surrogate for cerebral oxygen metabolism as it is influenced by both oxygen delivery and consumption. Furthermore, measurements of SO2 are not sensitive enough to detect brain injury hours after the insult 1,2, because oxygen consumption and delivery reach equilibrium after acute transients 3. We investigated the possibility of using more sophisticated NIRS optical methods to quantify cerebral oxygen metabolism at the bedside in healthy and brain-injured newborns. More specifically, we combined the frequency-domain NIRS (FDNIRS) measure of SO2 with the diffuse correlation spectroscopy (DCS) measure of blood flow index (CBFi) to yield an index of CMRO2 (CMRO2i) 4,5.
With the combined FDNIRS/DCS system we are able to quantify cerebral metabolism and hemodynamics. This represents an improvement over CWNIRS for detecting brain health, brain development, and response to therapy in neonates. Moreover, this method adheres to all neonatal intensive care unit (NICU) policies on infection control and institutional policies on laser safety. Future work will seek to integrate the two instruments to reduce acquisition time at the bedside and to implement real-time feedback on data quality to reduce the rate of data rejection.

We combined frequency-domain near-infrared spectroscopy measures of cerebral hemoglobin oxygenation with diffuse correlation spectroscopy measures of cerebral blood flow index to estimate an index of oxygen metabolism. We tested the utility of this measure as a bedside screening tool to evaluate the health and development of the newborn brain.

Perinatal brain injury remains a significant cause of infant mortality  and morbidity, but there is not yet an effective bedside tool that can  accurately ...

Nerve-sparing Mid-urethral Obstruction (NeMO) in Female Small Rodents

Partial bladder outlet obstruction (pBOO) has a high prevalence, causes significant patient burden, and immense health care costs. The most common animal model to investigate bladder remodeling in pBOO are female rodents undergoing partial obstruction at the proximal urethra. Variability in the degree of obstruction and animal mortality are major concerns with proximal obstruction. Furthermore, dissecting around the proximal urethra and bladder neck jeopardizes bladder innervation.
We developed a nerve-sparing mid-urethral obstruction (NeMO) model for pBOO avoiding the disadvantages of the traditional model. We approached the urethra just inferior to the pubic symphysis, which obviated the need for laparotomy as well as for dissection in this area; also, the striated urethral sphincter remained untouched. We performed NeMO in female Sprague-Dawley rats (12 obstructions, 6 sham animals) as well as in female C57/bl6 mice (20 obstructions, 18 sham animals). After two weeks, we evaluated bladder function, bladder mass, and body mass.
We had no mortalities among obstructed- or sham-operated female rats; as described for the traditional proximal pBOO-method, we tied the suture around the proximal urethra and a temporarily placed 0.9 mm metal rod. NeMO induced an 85% increase in bladder mass after two weeks, average residual urine volume was 0.4 mL in partially obstructed rats while only 0.03 mL in sham animals. In mice, we tested 3 sizes of cannulas that we placed along the urethra when tying the suture. We found that using a 27-gauge cannula resulted in over 50% animal mortality; placing the 25-gauge cannula did not yield the desired response in increasing bladder mass; utilizing a 26-gauge cannula yielded favorable results with minimal animal mortality (1/8) yet a significant 2-fold increase in bladder mass.

Nerve-sparing Mid-urethral Obstruction NeMO in Female Small Rodents

Traditional modeling of partial bladder outlet obstruction in rodents is fraught with animal mortality. A denervation injury from dissection around the proximal urethra and bladder neck is also of major concern. We developed and evaluated a safe and reliable mid-urethral obstruction model, avoiding the shortcomings of the traditional model.

Partial bladder outlet obstruction (pBOO) has a high prevalence, causes significant patient burden, and immense health care costs. The most common animal ...

Novel Methods for Intranasal Administration Under Inhalation Anesthesia to Evaluate Nose-to-Brain Drug Delivery

Intranasal administration has been reported to be a potential pathway for nose-to-brain delivery of therapeutic agents that circumvents the blood-brain barrier. However, there have been few reports regarding not only the quantitative analysis but also optimal administration conditions and dosing regimens for investigations of nose-to-brain delivery. The limited progress in research on nose-to-brain pathway mechanisms using rodents represents a significant impediment in terms of designing nose-to-brain delivery systems for candidate drugs.
To gain some headway in this regard, we developed and evaluated two novel methods of stable intranasal administration under inhalation anesthesia for experimental animals. We also describe a method for the evaluation of drug distribution levels in the brain via the nose-to-brain pathway using radio-labeled [14C]-inulin (molecular weight: 5,000) as a model substrate of water-soluble macromolecules.
Initially, we developed a pipette-based intranasal administration protocol using temporarily openable masks, which enabled us to perform reliable administration to animals under stable anesthesia. Using this system, [14C]-inulin could be delivered to the brain with little experimental error.
We subsequently developed an intranasal administration protocol entailing reverse cannulation from the airway side through the esophagus, which was developed to minimize the effects of mucociliary clearance (MC). This technique led to significantly higher levels of [14C]-inulin, which was quantitatively detected in the olfactory bulb, cerebrum, and medulla oblongata, than the pipette method. This appears to be because retention of the drug solution in the nasal cavity was substantially increased by active administration using a syringe pump in a direction opposite to the MC into the nasal cavity.
In conclusion, the two methods of intranasal administration developed in this study can be expected to be extremely useful techniques for evaluating pharmacokinetics in rodents. The reverse cannulation method, in particular, could be useful for evaluating the full potential of nose-to-brain delivery of drug candidates.

Here, we describe two novel methods of stable intranasal administration under inhalation anesthesia with minimal physical stress for experimental animals. We also describe a method for quantitative evaluation of drug distribution levels in the brain via the nose-to-brain pathway using radiolabeled [14C]-inulin as a model substrate of water-soluble macromolecules.

Intranasal administration has been reported to be a potential pathway for nose-to-brain delivery of therapeutic agents that circumvents the blood-brain ...

CO2-Lasertonsillotomy Under Local Anesthesia in Adults

Tonsil-related complaints are very common among the adult population. Tonsillectomy under general anesthesia is currently the most performed surgical treatment in adults for such complaints. Unfortunately, tonsillectomy is an invasive treatment associated with a high complication rate and a long recovery time. Complications and a long recovery time are mostly related to removing the vascular and densely innervated capsule of the tonsils. Recently, CO2-lasertonsillotomy under local anesthesia has been demonstrated to be a viable alternative treatment for tonsil-related disease with a significantly shorter and less painful recovery period. The milder side-effect profile of CO2-lasertonsillotomy is likely related to leaving the tonsil capsule intact. The aim of the current report is to present a concise protocol detailing the execution of CO2-lasertonsillotomy under local anesthesia. This intervention has been performed successfully in our hospital in more than 1,000 patients and has been found to be safe and to be associated with a steep learning curve.

CO2-Lasertonsillotomy Under Local Anesthesia in Adults

CO2-lasertonsillotomy under local anesthesia is an interesting alternative treatment method for tonsillectomy under general anesthesia for tonsil-related complaints in adults. This report presents a step-by-step protocol detailing the execution of CO2-lasertonsillotomy under local anesthesia.

Tonsil-related complaints are very common among the adult population. Tonsillectomy under general anesthesia is currently the most performed surgical ...

International Expert Consensus and Recommendations for Neonatal Pneumothorax Ultrasound Diagnosis and Ultrasound-guided Thoracentesis Procedure

Pneumothorax (PTX) represents accumulation of the air in the pleural space. A large or tension pneumothorax can collapse the lung and cause hemodynamic compromise, a life-threatening disorder. Traditionally, neonatal pneumothorax diagnosis has been based on clinical images, auscultation, transillumination, and chest X-ray findings. This approach may potentially lead to a delay in both diagnosis and treatment. The use of lung US in diagnosis of PTX together with US-guided thoracentesis results in earlier and more precise management. The recommendations presented in this publication are aimed at improving the application of lung US in guiding neonatal PTX diagnosis and management.

Pneumothorax is a common emergency and critical disease in newborn infants that needs rapid, clear diagnosis and timely treatment. Diagnosis and treatment based on chest X-rays are associated with delayed management and radiation damage. Lung ultrasound (US) provides useful guidance for rapid, accurate diagnosis and the precise thoracentesis of pneumothorax.

Pneumothorax (PTX) represents accumulation of the air in the pleural space. A large or tension pneumothorax can collapse the lung and cause hemodynamic ...

How to Administer Near-Infrared Spectroscopy in Critically ill Neonates, Infants, and Children

Near infrared spectroscopy (NIRS) calculates regional tissue oxygenation (rSO2) using the different absorption spectra of oxygenated and deoxygenated hemoglobin molecules. A probe placed on the skin emits light that is absorbed, scattered, and reflected by the underlying tissue. Detectors in the probe sense the amount of reflected light: this reflects the organ-specific ratio of oxygen supply and consumption - independent of pulsatile flow. Modern devices enable the simultaneous monitoring at different body sites. A rise or dip in the rSO2 curve visualizes changes in oxygen supply or demand before vital signs indicate them. The evolution of rSO2 values in relation to the starting point is more important for interpretation than are absolute values.
A routine clinical application of NIRS is the surveillance of somatic and cerebral oxygenation during and after cardiac surgery. It is also administered in preterm infants at risk for necrotizing enterocolitis, newborns with hypoxic ischemic encephalopathy and a potential risk of impaired tissue oxygenation. In the future, NIRS could be increasingly used in multimodal neuromonitoring, or applied to monitor patients with other conditions (e.g., after resuscitation or traumatic brain injury).

This protocol is designed to assist clinicians to measure regional tissue oxygenation at different body sites in infants and children. It can be used in situations where tissue oxygenation is potentially compromised, particularly during cardiopulmonary bypass, when using non-pulsatile cardiac-assist devices, and in critically ill neonates, infants and children.

Near infrared spectroscopy (NIRS) calculates regional tissue oxygenation (rSO2) using the different absorption spectra of oxygenated and deoxygenated ...

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the recognized standard-of-care for blood flow quantification based on phase contrast MRI. While such measurement of blood flow has been possible in adults for decades, methods to extend this capability to fetal blood flow have only recently been developed.
Fetal blood flow quantification in major vessels is important for monitoring fetal pathologies such as congenital heart disease (CHD) and fetal growth restriction (FGR). CHD causes alterations in the cardiac structure and vasculature that change the course of blood in the fetus. In FGR, the path of blood flow is altered through the dilation of shunts such that the oxygenated blood supply to the brain is increased. Blood flow quantification enables assessment of the severity of the fetal pathology, which in turn allows for suitable&#160;in utero&#160;patient management and planning for postnatal care.
The primary challenges of applying phase contrast MRI to the human fetus include small blood vessel size, high fetal heart rate, potential MRI data corruption due to maternal respiration, unpredictable fetal movements, and lack of conventional cardiac gating methods to synchronize data acquisition. Here, we describe recent technical developments from our lab that have enabled the quantification of fetal blood flow using phase contrast MRI, including advances in accelerated imaging, motion compensation, and cardiac gating.

Here we present a protocol for measuring fetal blood flow rapidly with MRI and retrospectively performing motion correction and cardiac gating.

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the ...

A Non-Intubation Protocol for Video-Assisted Thoracoscopic Surgery with Preserved Autonomic Breathing

Non-Intubated Video-Assisted Thoracoscopic Surgery

Double-lumen intubation under general anesthesia is currently the most commonly performed intubation technique for pneumonectomy, wedge resection of the lung, and lobectomy. However, there is a high incidence of pulmonary complications arising from general anesthesia with tracheal intubation. Non-intubation with the preservation of voluntary breathing is an alternative to anesthesia. Non-intubation procedures minimize the adverse effects of tracheal intubation and general anesthesia, such as intubation-related airway trauma, ventilation-induced lung injury, residual neuromuscular blockade, and post-operative nausea and vomiting. However, the steps for non-intubation procedures are not detailed in many studies. Here, we present a concise non-intubated protocol for the performance of video-assisted thoracoscopic surgery with preserved autonomic breathing. This article identifies the conditions necessary to convert from non-intubated to intubated anesthesia and also discusses the advantages and limitations of non-intubated anesthesia. In this work, this intervention was performed on 58 patients. In addition, the results of a retrospective study are presented. Compared with intubated general anesthesia, patients in the non-intubated video-assisted thoracic surgery group had lower rates of post-operative pulmonary complications, shorter operative times, less intraoperative blood loss, shorter PACU stays, a lower number of days to chest drain removal, less post-operative drainage, and shorter hospital stays.

Author Spotlight: A Non-Intubated Video-Assisted Thoracoscopic Surgery with Multimodal Analgesia and Sevoflurane Inhalation Anesthesia 

Here, we present a non-intubated protocol for performing video-assisted thoracoscopic surgery with preserved autonomic breathing.

Double-lumen intubation under general anesthesia is currently the most commonly performed intubation technique for pneumonectomy, wedge resection of the ...