The authors want to thank Dagmar Dirvonskis for her excellent technical support.

The experiments in this protocol were approved by the State and Institutional Animal Care Committee (Landesuntersuchungsamt Rheinland-Pfalz, Koblenz, Germany; approval no. G20-1-135). The experiments were conducted following the ARRIVE guidelines. Overall, 10 anesthetized male pigs (Sus scrofa domestica) with a mean weight of 30 kg &#177; 2 kg and 12-16 weeks in age were used for the present study.
1. Animal preparation
<ol>
	<li>Maintain a normal environment for the animals to minimize stress. Withhold food 6 h before the scheduled experiment to lower the risk of aspiration, but allow access to water.</li>
	<li>Sedate the pigs with a combined injection of midazolam (0.5 mg/kg) and azaperone (2-3 mg/kg) (see Table of Materials) in the gluteal muscle or neck with a needle (20 G) for intramuscular injection. Leave the animals undisturbed until sedation sets in (15-20 min). 
	NOTE: Depending on national regulations, the administration of sedating agents may be subject to scrutiny and may or may not require the supervision of a trained veterinarian. Consult with the local authorities before planning the experiments.</li>
	<li>Transport the sedated animals from the stables to the laboratory. The transport time must not exceed adequate sedation time (here, 30-60 min). Ensure sufficient heat retention so that the animal does not get hypothermic (i.e., below 38 &#176;C), such as by covering the body with a blanket depending on the outside temperature.</li>
	<li>Using a sensor (see Table of Materials) clipped to the ear or tail, monitor the peripheral oxygen saturation (SpO2).</li>
	<li>Disinfect the skin with a disinfectant (alcoholic) before inserting a peripheral vein cannula (22 G) into an ear vein. Spray the area, wipe once, then spray again, and allow the disinfectant to dry. Secure the ear cannula with a band-aid (See Table of Materials).</li>
</ol>
2. Anesthesia and mechanical ventilation
<ol>
	<li>Administer analgesia through an intravenous injection of 4 &#181;g/kg of fentanyl. Induce anesthesia with an intravenous injection of 3 mg/kg of propofol (see Table of Materials). 
	NOTE: Due to the bolus application, the drug quickly floods into the active compartment, providing a fast onset of deep anesthesia.</li>
	<li>Place the pig on a stretcher in a supine position and fix it with bandages. Apply muscle relaxant through an intravenous injection of 0.5 mg/kg of atracurium (see Table of Materials).</li>
	<li>Instantaneously start noninvasive ventilation via a dog ventilation mask (see Table of Materials) or similar models. To ensure a tight fit of the mask, place the thenar eminence and the thumbs of both hands on top of the mask while performing jaw thrust with the remaining fingers. 
	NOTE: Ventilation parameters: FiO2 (inspiratory oxygen fraction) = 100%, peak inspiratory pressure = &#60;20 cmH20, respiratory rate = 18-20 breaths/min, PEEP (positive end-expiratory pressure) = 5 cmH20.</li>
	<li>Maintain anesthesia through continuous infusion of 0.1-0.2 mg/kg/h of fentanyl and 8-12 mg/kg/h of propofol. Start infusing with 5 mL/kg/h of balanced electrolyte solution (see Table of Materials) continuously. Constantly maintain an adequate depth of anesthesia. 
	&#8203;NOTE: Surrogate parameters for this are the absence of movement, the lack of own respiratory efforts after intubation, and the absence of a sudden increase in heart rate. If possible, avoid permanent muscle relaxation to enable motor reactions as a sign of insufficient depth of anesthesia.</li>
</ol>
3. Endotracheal intubation
<ol>
	<li>Have an assistant stand on the left side of the head. Have the assistant&#39;s left hand open the mouth and pinch the tongue outward and left with a compress. Ask the assistant to press down on the right upper lip with the right index finger to provide a better mouth opening.</li>
	<li>Perform direct laryngoscopy. To do this, insert the laryngoscope (see Table of Materials) into the right side of the mouth and push it forward while pushing the tongue to the left. Advance the tip of the laryngoscope until it rests in the epiglottic vallecula. 
	NOTE: The epiglottis usually obscures the glottis by sticking to the soft palate.</li>
	<li>Carefully push the epiglottis aside with a tube guiding wire (see Table of Materials) with a gentle scooping motion from the right piriform recess to the left along the soft palate.</li>
	<li>Pass the handle of the laryngoscope to the assistant to fix it in the current position.</li>
	<li>Now, take the flexible intubation endoscope onto which an endotracheal tube has already been mounted and that is connected to a video monitor. Insert the endoscope orally and advance it over the base of the tongue until the glottis is visualized. 
	NOTE: To avoid fogging of the camera, the prior application of anti-fogging agents (see Table of Materials) is recommended.</li>
	<li>Advance the endoscope between the vocal ligaments into the trachea. Confirm the anatomy of the trachea by visually identifying the cartilaginous rings and the pars membranacea. Advance the endoscope until it rests above the carina. Try not to touch the sensitive mucosa with the tip of the endoscope to avoid swelling and bleeding.</li>
	<li>While maintaining the position of the endoscope, advance the endotracheal tube until it becomes visible in the camera image. 
	NOTE: If the endotracheal tube cannot be advanced through the glottic plane, there is a possibility that it has become caught on the arytenoid cartilage. In this case, the endotracheal tube must be withdrawn 1 cm and rotated by 90&#176; before gently advancing again. If necessary, this maneuver can be repeated. Similar calibers of flexible intubation endoscope and endotracheal tube can minimize the risk of this issue occurring. If the endotracheal tube cannot be advanced despite this maneuver, it is likely that the subglottic narrowness-the narrowest part of the porcine larynx-cannot be passed. In this case, a smaller endotracheal tube size needs to be selected. Regular commercially available endotracheal tubes in sizes 6.5 cm or 7.0 cm ID should be able to pass the glottis as long as no anatomic abnormalities are present. Endotracheal tube size requirements vary depending on the piglet size and breed.</li>
	<li>Withdraw the flexible intubation endoscope while maintaining the position of the endotracheal tube.</li>
	<li>Using a 10 mL syringe, inflate the cuff with 10 mL of air. Control the cuff pressure with a cuff manager (target value: 30 cmH2O, see Table of Materials).</li>
	<li>Confirm the correct placement of the endotracheal tube and adequate ventilation by periodic and regular exhalation of carbon dioxide via capnography24 and double-sided ventilation via auscultation15.</li>
	<li>Start mechanical ventilation after connecting the tube with a ventilator (PEEP = 5 cmH2O, respiratory rate = variable to achieve an end-tidal CO2 of &#60;6 kPa, usually 30-50 min&#8722;1, FiO2 = 0.4, I:E (inspiration to expiration ratio) = 1:2, tidal volume = 6-8 mL/kg).</li>
	<li>Expand the monitoring (e.g., the establishment of an intra-arterial blood pressure measurement, the installation of a central venous or pulmonary arterial catheter27) or continue with the intervention. 
	NOTE: Depending on the question of the further experiments, define limit values for the vital parameters and intervention options and establish the monitoring accordingly in the study protocol.</li>
</ol>

The flexible intubation endoscope and its accessories have been provided unconditionally by the manufacturer for research purposes only. The authors declare no further financial or other conflicts of interest.

In previous studies, our research group has already described specific details regarding the translational benefits of the porcine model2,27,32,33. Generally, reducing the stress level of the animal and unnecessary pain should be an integral part of any study protocol and is paramount for generating reliably reproducible data. Therefore, awake endoscopically guided intubation of the pig with an...

An erratum was issued for:&#160;<a href="https://jove.unicartagenaproxy.elogim.com/t/63955">Endotracheal Intubation Using a Flexible Intubation Endoscope As a Standardized Model for Safe Airway Management in Swine</a>. The Protocol, Representative Results, and Discussion sections were updated.
In the Protocol, step 1.5 was updated from:
Disinfect the skin with a disinfectant (alcoholic) before inserting a peripheral vein cannula (22 G) into an ear vein. Spray the area, wipe once, then spray again, and allow the disinfectant to dry.
to:
Disinfect the skin with a disinfectant (alcoholic) before inserting a peripheral vein cannula (22 G) into an ear vein. Spray the area, wipe once, then spray again, and allow the disinfectant to dry. Secure the ear cannula with a band-aid (See Table of Materials).
In the Protocol, step 3.7 was updated from:
While maintaining the position of the endoscope, advance the endotracheal tube until it becomes visible in the camera image. 
NOTE: If the endotracheal tube cannot be advanced through the glottic plane, there is a possibility that it has become caught on the arytenoid cartilage. In this case, the endotracheal tube must be withdrawn 1 cm and rotated by 90&#176; before gently advancing again. If necessary, this maneuver can be repeated. Similar calibers of flexible intubation endoscope and endotracheal tube can minimize the risk of this issue occurring. If the endotracheal tube cannot be advanced despite this maneuver, it is likely that the subglottic narrowness-the narrowest part of the porcine larynx-cannot be passed. In this case, a smaller endotracheal tube size needs to be selected. Regular commercially available endotracheal tubes in sizes 6.5 cm or 7.0 cm ID should be able to pass the glottis as long as no anatomic abnormalities are present.
to:
While maintaining the position of the endoscope, advance the endotracheal tube until it becomes visible in the camera image. 
NOTE: If the endotracheal tube cannot be advanced through the glottic plane, there is a possibility that it has become caught on the arytenoid cartilage. In this case, the endotracheal tube must be withdrawn 1 cm and rotated by 90&#176; before gently advancing again. If necessary, this maneuver can be repeated. Similar calibers of flexible intubation endoscope and endotracheal tube can minimize the risk of this issue occurring. If the endotracheal tube cannot be advanced despite this maneuver, it is likely that the subglottic narrowness-the narrowest part of the porcine larynx-cannot be passed. In this case, a smaller endotracheal tube size needs to be selected. Regular commercially available endotracheal tubes in sizes 6.5 cm or 7.0 cm ID should be able to pass the glottis as long as no anatomic abnormalities are present. Endotracheal tube size requirements vary depending on the piglet size and breed.
In the Representative Results, the sixth paragraph was updated from:
Statistical analyses were performed using commercially available software (see Table of Materials). Normal distribution was examined using the Kolmogorov-Smirnoff test28. If a normal distribution was determined, group differences were analyzed using t-tests of independent samples29 or the Mann-Whitney U test30 for the non-parametric version. Data are presented as mean (&#177; standard deviation). Correlations of ordinal-scale data were examined using Spearman&#39;s correlation coefficient31. A significance level of p &#60; 0.05 was assumed.
to:
Statistical analyses were performed using commercially available software (see Table of Materials). Normal distribution was examined using the Kolmogorov-Smirnoff test28. If a normal distribution was determined, group differences were analyzed using t-tests of independent samples29 or the Mann-Whitney U test30 for the non-parametric version. Data are presented as mean (&#177; standard deviation). Correlations of ordinal-scale data were examined using Spearman&#39;s correlation coefficient31. A significance level of p &#60; 0.05 was assumed. All tests were performed with exploratory intention; therefore p-values are descriptive. Nevertheless, p &#60; 0.05 was accepted as indicative of statistical significance.
In the Representative Results, the legend for figure 1 was updated from:
Figure 1: Number of intubation attempts in group comparison. For the group that was intubated using a flexible intubation endoscope, every intubation attempt was successful; in the group that was conventionally intubated, it took an average of 1.4 attempts before the endotracheal tube could be placed correctly. Error bars show the standard deviation. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/63955/63955fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
to:
Figure 1: Number of intubation attempts in group comparison. For the group that was intubated using a flexible intubation endoscope, every intubation attempt was successful; in the group that was conventionally intubated, it took an average of 1.4 attempts before the endotracheal tube could be placed correctly. Error bars show the standard deviation. n = 5 (for each group).&#160;<a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/63955/63955fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In the Representative Results, figure 2 was updated from:
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63955/63955fig02.jpg" /> 
Figure 2: Time until CO2 detection in group comparison. For the group that was intubated using a flexible intubation endoscope, it took significantly longer until end-tidal CO2 could be detected, depicted as mean and standard deviation. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/63955/63955fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
to:
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/63955/63955fig2v2.jpg" /> 
Figure 2: Time until CO2 detection in group comparison. For the group that was intubated using a flexible intubation endoscope, it took significantly longer until end-tidal CO2 could be detected, depicted as mean and standard deviation. n = 5 (for each group).&#160;<a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/63955/63955fig2v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In the Discussion, the fifth paragraph was updated from:
The increased duration had no clinical significance in this cohort. At no time was the termination criterion-a saturation of less than 93%-reached. This is shown in the results because a procedure change was unnecessary at any time. Prior adequate mask ventilation is a critical step to allow sufficient time for fiberoptic endotracheal tube placement to avoid rapid desaturation34. These results are consistent with previous studies comparing conventional intubation and endoscopically assisted intubations with inexperienced providers35.
to:
The increased duration had no clinical significance in this cohort. At no time was the termination criterion-a saturation of less than 93%-reached. This is shown in the results because a procedure change was unnecessary at any time. Prior adequate mask ventilation is a critical step to allow sufficient time for fiberoptic endotracheal tube placement to avoid rapid desaturation34. These results are consistent with previous studies comparing conventional intubation and endoscopically assisted intubations with inexperienced providers35. We attribute the prolonged duration of fiberoptic intubation to the fact that one must first reorient again after insertion, whereas with conventional intubation, one retains a view of the glottis. It is also important to avoid contact with the mucosa with the flexible intubation endoscope during advancement. This requires occasional corrective maneuvers. Last but not least, after successful placement, retraction of the relatively long endoscope is required, which increases the time to CO2 detection slightly.

An erratum was issued for:&#160;<a href="https://jove.unicartagenaproxy.elogim.com/t/63955">Endotracheal Intubation Using a Flexible Intubation Endoscope As a Standardized Model for Safe Airway Management in Swine</a>. The Protocol, Representative Results, and Discussion sections were updated.

Erratum: Endotracheal Intubation Using a Flexible Intubation Endoscope As a Standardized Model for Safe Airway Management in Swine

Endotracheal intubation is often a basic requirement for translational research in porcine models for various interventions that require a secured airway or high ventilation pressures (such as ventilation during cardiopulmonary resuscitation1 or acute respiratory distress syndrome2) or require that cerebral blood flow is not compromised through internal compression by supraglottic airway devices3, which are occasionally propagated as alternatives in the context of an anticipated difficult airway in pigs4,5.
While the lung physiology of pigs shows similar features to that of humans6, securing the airway is sometimes significantly more difficult7 due to specific differences in the porcine orotracheal anatomy. The snout of a pig has a narrow opening with a very large tongue, the larynx is extremely mobile, and the epiglottis is relatively large, with a free end that extends to the soft palate. Caudally, the larynx forms an obtuse angle with the trachea. The arytenoid cartilages are large8. The narrowest part of the airway is at the subglottic level9, comparable to the airway anatomy of children10. Since the larynx in pigs is very mobile, there is a risk that the end of the endotracheal tube will pass through the vocal cords but the larynx will only be displaced caudally by up to several centimeters, which may be mistaken for a correct intubation8,11. Additionally, esophageal intubation is a common risk when dealing with porcine airway management12.
The rates of difficult or impossible endotracheal intubations with a corresponding negative impact on the experiment or early mortality have not been systematically recorded, but several case reports have been published13,14. In humans, there is the possibility of using a flexible intubation endoscope in the context of an unexpectedly difficult conventional intubation15. Various false intubations often precede this measure. These repeated intubation attempts are associated with adverse events in humans16,17, especially airway complications18. Such events are deleterious in test animals since, in the simplest case, they represent a confounder variable in the experiment; in the worst case, they can lead to the unnecessary loss of the animal.
The present study has developed a model based on the guidelines for expected difficult airway management in humans15,19,20,21,22,23,24. Previously, a similar technique has been described for learning fiberoptic intubation in human studies25,26. The protocol presented in this report aims to provide a standardized and easy-to-adapt intubation model that also allows non-airway specialists to perform successful and safe endotracheal intubation in pigs.

<table><tbody><tr><td>Ambu aScope Regular</td><td>Ambu GmbH, Medizinprodukte, Bad Nauheim, Germany</td><td></td><td>Disposable fiber optic outer diameter 5 mm</td></tr><tr><td>Ambu aView Monitor</td><td>Ambu GmbH, Medizinprodukte, Bad Nauheim, Germany</td><td></td><td>monitor</td></tr><tr><td>Atracurium Hikma 50 mg/5mL</td><td>Hikma Pharma GmbH, Martinsried</td><td></td><td>atracurium</td></tr><tr><td>Azaperone (Stresnil) 40mg/mL</td><td>Lilly Deutschland GmbH, Bad Homburg, Germany</td><td></td><td>azaperone</td></tr><tr><td>BD Discardit II Spritze 2, 5, 10, 20 mL</td><td>Becton Dickinson S.A. Carretera, Mequinenza Fraga, Spain</td><td></td><td>syringe</td></tr><tr><td>BD Luer Connecta</td><td>Becton Dickinson Infusion Therapy, AB Helsingborg, Schweden</td><td></td><td>3-way-stopcock</td></tr><tr><td>BD Microlance 3 20 G</td><td>Becton Dickinson S.A. Carretera, Mequinenza Fraga, Spain</td><td></td><td>cannula</td></tr><tr><td>Curafix i.v. classics</td><td>Lohmann &amp;amp; Rauscher International GmbH &amp;amp; Co. KG, Rengsdorf, Germany</td><td></td><td>Cannula retention dressing</td></tr><tr><td>Engstr&amp;ouml;m Carestation</td><td>GE Heathcare, Madison USA</td><td></td><td>ventilator</td></tr><tr><td>Fentanyl-Janssen 0.05 mg/mL</td><td>Janssen-Cilag GmbH, Neuss</td><td></td><td>fentanyl</td></tr><tr><td>F&amp;uuml;hrungsstab, Durchmesser 4.3</td><td>R&amp;uuml;sch</td><td></td><td>endotracheal tube introducer</td></tr><tr><td>IBM SPSS Statistics for Windows, Version 20</td><td>IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.)</td><td></td><td>Statistical software</td></tr><tr><td>Incetomat-line 150 cm</td><td>Fresenius, Kabi Deutschland, GmbH</td><td></td><td>perfusor line</td></tr><tr><td>Intrafix Primeline</td><td>B. Braun Melsungen AG, Melsungen, Germany</td><td></td><td>Infusion line</td></tr><tr><td>JOZA Einmal Nitril Untersuchungshandschuhe</td><td>JOZA, M&amp;uuml;nchen, Germany</td><td></td><td>disposable gloves</td></tr><tr><td>Laryngoscope, 45.48.50, KL 2000</td><td>Medicon</td><td></td><td>Laryngoscope handle</td></tr><tr><td>Littmann Classic III Stethoscope</td><td>3M Deutschland GmbH, Neuss, Germany</td><td></td><td>stethoscope</td></tr><tr><td>Luer Lock</td><td>B.Braun Melsungen AG, Germany</td><td></td><td></td></tr><tr><td>Maimed Vlieskompresse</td><td>Maimed GmbH, Neuenkirchen, Germany</td><td></td><td>Fleece compress to fix the tongue</td></tr><tr><td>Masimo LNCS Adtx SpO&lt;sub&gt;2 &lt;/sub&gt;sensor</td><td>Masimo Corporation Irvine, Ca 92618 USA</td><td></td><td>saturation clip for the tail</td></tr><tr><td>Masimo LNCS TC-I SpO&lt;sub&gt;2&lt;/sub&gt; ear clip sensor</td><td>Masimo Corporation Irvine, Ca 92618 USA</td><td></td><td>Saturation clip for the ear</td></tr><tr><td>Masimo Radical 7</td><td>Masimo Corporation Irvine, Ca 92618 USA</td><td></td><td>periphereal oxygen saturation</td></tr><tr><td>Midazolam 15 mg/3 mL</td><td>Hameln Pharma GmbH, Hameln, Germany</td><td></td><td>midazolam</td></tr><tr><td>Midmark Canine Mask Small Plastic with Diaphragm FRSCM-0005</td><td>Midmark Corp., Dayton, Ohio, USA</td><td></td><td>dog ventilation mask</td></tr><tr><td>Octeniderm farblos</td><td>Sch&amp;uuml;lke &amp;amp; Mayr GmbH, Nordenstedt, Germany</td><td></td><td>Alcoholic disinfectant</td></tr><tr><td>Original Perfusor syringe 50 mL</td><td>B.Braun Melsungen AG, Germany</td><td></td><td>perfusor syringe</td></tr><tr><td>Perfusor FM Braun</td><td>B.Braun Melsungen AG, Germany</td><td></td><td>syringe pump</td></tr><tr><td>Propofol 2% 20 mg/mL (50 mL flasks)</td><td>Fresenius, Kabi Deutschland, GmbH</td><td></td><td>propofol</td></tr><tr><td>R&amp;Uuml;SCH F&amp;uuml;hrungsstab f&amp;uuml;r Endotrachealtubus (ID 5.6 mm)</td><td>Teleflex Medical Sdn. Bhd, Malaysia</td><td></td><td>PVC coated tube guiding wire</td></tr><tr><td>R&amp;uuml;schelit Super Safety Clear &gt;ID 6/6.5 /7.0 mm</td><td>Teleflex Medical Sdn. Bhd, Malaysia</td><td></td><td>endotracheal tube</td></tr><tr><td>Stainless Macintosh Gr&amp;ouml;&amp;szlig;e 4</td><td>Welch Allyn69604</td><td></td><td>blade for laryngoscope</td></tr><tr><td>Sterofundin</td><td>B.Braun Melsungen AG, Melsungen, Germany</td><td></td><td>Balanced electrolyte solution</td></tr><tr><td>Ultrastop Antibeschlagmittel bottle with dropper 25 mL</td><td>Sigmapharm Arzneimittel GmbH, Wien, Austria</td><td></td><td>Antifog agent</td></tr><tr><td>Vasofix Safety 22 G-16 G</td><td>B.Braun Melsungen AG, Germany</td><td></td><td>venous catheter</td></tr><tr><td>VBM Cuff Manometer</td><td>VBM Medizintechnik GmbH, Sulz a.N., Germany</td><td></td><td>cuff pressure gauge</td></tr><tr><td>Zelette</td><td>Lohmann &amp;amp; Rauscher International GmbH &amp;amp; Co. KG, Rengsdorf, Germany</td><td></td><td>Tissue swab</td></tr></tbody></table>

endotracheal intubation using a flexible intubation endoscope as a standardized model for safe airway management in swine

Endotracheal intubation is often a basic requirement for translational research in porcine models for various interventions that require a secured airway or high ventilation pressures. Endotracheal intubation is a challenging skill,&#160;requiring a minimum number of successful endotracheal intubations to achieve a high success rate under optimal conditions, which is often unachievable for non-anaesthesiology researchers. Due to the specific porcine airway anatomy, a difficult airway can usually be assumed. The impossibility of establishing a secure airway can result in injury, adverse events, or death of the laboratory animal. Using a prospective, randomized, controlled evaluation approach, it has been shown that fiberoptic-assisted endotracheal intubation takes longer but has a higher first-pass success rate than conventional intubation without causing clinically relevant drops in oxygen saturation. This model presents a standardized regimen for endoscopically guided endotracheal intubation, providing a secured airway, especially for researchers who are inexperienced in the technique of endotracheal intubation via direct laryngoscopy. This procedure is expected to minimize animal suffering and unnecessary animal losses.

Endotracheal intubation was performed on 10 male pigs (age 12-16 weeks, weight 30 kg &#177; 3 kg) in a prospective, randomized, controlled study setting. The pigs were randomized into two groups: one was conventionally laryngoscopically intubated (CI group), and the other group was intubated assisted via a flexible intubation endoscope as described in the protocol (FIE group). The group assignment was done by pulling sealed envelopes. The investigator was assigned randomly on a daily basis.
<p class="jove_co...

Watch this Scientific Journal Video about Endotracheal Intubation Using a Flexible Intubation Endoscope as a Standardized Model for Safe Airway Management in Swine at JoVE.com

Endotracheal Intubation Using a Flexible Intubation Endoscope as a Standardized Model for Safe Airway Management in Swine

The use of pigs in research has increased in recent years. Nevertheless, pigs are characterized by difficult airway anatomy. By demonstrating how to perform endoscopically guided endotracheal intubation, the present protocol aims to further increase laboratory animals' safety to avoid animal suffering and unnecessary death.

Endotracheal intubation is often a basic requirement for translational research in porcine models for various interventions that require a secured airway ...

endotracheal-intubation-using-flexible-intubation-endoscope-as

Universidad de Cartagena UDEC

Research

JoVE Journal

Medicine

2.9K Views.  University Medical Center of the Johannes Gutenberg-University. The use of pigs in research has increased in recent years. Nevertheless, pigs are characterized by difficult airway anatomy. By demonstrating how to perform endoscopically guided endotracheal intubation, the present protocol aims to further increase laboratory animals' safety to avoid animal suffering and unnecessary death.

Video: Endotracheal Intubation Using a Flexible Intubation Endoscope as a Standardized Model for Safe Airway Management in Swine

Endotracheal Intubation in Mice via Direct Laryngoscopy Using an Otoscope

Mice, both wildtype and transgenic, are the principal mammalian model in biomedical research currently. Intubation and mechanical ventilation are necessary for whole animal experiments that require surgery under deep anesthesia or measurements of lung function. Tracheostomy has been the standard for intubating the airway in these mice to allow mechanical ventilation. Orotracheal intubation has been reported but has not been successfully used in many studies because of the substantial technical difficulty or a requirement for highly specialized and expensive equipment. Here we report a technique of direct laryngoscopy using an otoscope fitted with a 2.0 mm speculum and using a 20 G&#160;intravenous catheter as an endotracheal tube. We have used this technique extensively and reliably to intubate and conduct accurate assessments of lung function in mice. This technique has proven safe, with essentially no animal loss in experienced hands. Moreover, this technique can be used for repeated studies of mice in chronic models.

Endotracheal Intubation in Mice via Direct Laryngoscopy Using an Otoscope

We have developed a simple, reliable, and relatively inexpensive method for endotracheal intubation in mice via direct laryngoscopy using an otoscope with a 2.0 mm speculum. This technique is atraumatic and can be used for repeated measurements in chronic experiments. We find it superior to tracheostomy or previously reported nonsurgical techniques.

Mice, both wildtype and transgenic, are the principal mammalian model in biomedical research currently. Intubation and mechanical ventilation are ...

Standardized Model of Ventricular Fibrillation and Advanced Cardiac Life Support in Swine

Cardiopulmonary resuscitation after cardiac arrest, independent of its origin, is a regularly encountered medical emergency in hospitals as well as preclinical settings. Prospective randomized trials in human subjects are difficult to design and ethically ambiguous, which results in a lack of evidence-based therapies. The model presented in this report represents one of the most common causes of cardiac arrests, ventricular fibrillation, in a standardized setting in a large animal model. This allows for reproducible observations and various therapeutic interventions under clinically accurate conditions, hence facilitating the generation of better evidence and eventually the potential for improved medical treatment.

Cardiopulmonary resuscitation and defibrillation are the only effective therapeutic options during cardiac arrest caused by ventricular fibrillation. This model presents a standardized regimen to induce, assess, and treat this physiological state in a porcine model, thus providing a clinical approach with various opportunities for data collection and analysis.

Cardiopulmonary resuscitation after cardiac arrest, independent of its origin, is a regularly encountered medical emergency in hospitals as well as ...

The Rigid Tube as an Alternative in Controlling the Problematic Airway

The unexpected problematic airway represents a large proportion of anesthesia-related morbidity and mortality. The retromolar or paraglossal approach is an alternative to the majority of the rigid instruments used for tracheal intubation, which follow the midline to access the glottis. This single-center, prospective case-series study offers an option to conventional laryngoscopy in case of a poor glottic view, introducing an instrument (the rigid tube for laryngoscopy) that uses the retromolar approach to accomplish tracheal intubation. If after anesthesia induction, the modified Cormack-Lehane glottis view grade &#62;2b, the intubation is carried further with the rigid tube. The tube follows the direction of the thyroid cartilage while advancing from the labial commissure, displacing the tongue to the contralateral side. Adjusting the position of the larynx with the nondominant hand by gently pushing the thyroid cartilage and following an imaginary line towards it while advancing it improves the time needed for proper glottis visualization. Once the epiglottis is in sight, the practitioner progresses slowly, lifting the epiglottis and aiming the tip of the tube more anteriorly. When the glottis appears in the visual field, the intubating tube introducer is placed in the trachea, and a lubricated cuffed intubating tube is advanced over the introducer after the rigid tube is extracted. This tool was tested on 30 patients with an unsatisfactory glottic view when using the Macintosh laryngoscope and obtained excellent results with respect to intubation time and complications. The reduced visual field is the main limitation of this method, which requires a training period for reasonable expertise. This simple, robust, and cheap instrument could be a rescue option in case of a difficult airway.

Presented here is a protocol of tracheal intubation over an intubating tube introducer using a rigid tube for laryngoscopy with an attached light source. The main characteristics of this maneuver are the retromolar approach and the use of the thyroid cartilage as a landmark while advancing the rigid tube.

The unexpected problematic airway represents a large proportion of anesthesia-related morbidity and mortality. The retromolar or paraglossal approach is ...

Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device

Acute respiratory distress syndrome (ARDS) is a common cause of hypoxemic respiratory failure and death in critically ill patients, and there is an urgent need to find effective therapies. Preclinical studies have shown that inhaled halogenated agents may have beneficial effects in animal models of ARDS. The development of new devices to administer halogenated agents using modern intensive care unit (ICU) ventilators has significantly simplified the dispensing of halogenated agents to ICU patients. Because previous experimental and clinical research suggested potential benefits of halogenated volatiles, such as sevoflurane or isoflurane, for lung alveolar epithelial injury and inflammation, two pathophysiologic landmarks of diffuse alveolar damage during ARDS, we designed an animal model to understand the mechanisms of the effects of halogenated agents on lung injury and repair. After general anesthesia, tracheal intubation, and the initiation of mechanical ventilation, ARDS was induced in piglets via the intratracheal instillation of hydrochloric acid. Then, the piglets were sedated with inhaled sevoflurane or isoflurane using an ICU-type device, and the animals were ventilated with lung-protective mechanical ventilation during a 4 h period. During the study period, blood and alveolar samples were collected to evaluate arterial oxygenation, the permeability of the alveolar-capillary membrane, alveolar fluid clearance, and lung inflammation. Mechanical ventilation parameters were also collected throughout the experiment. Although this model induced a marked decrease in arterial oxygenation with altered alveolar-capillary permeability, it is reproducible and is characterized by a rapid onset, good stability over time, and no fatal complications.
We have developed a piglet model of acid aspiration that reproduces most of the physiological, biological, and pathological features of clinical ARDS, and it will be helpful to further our understanding of the potential lung-protective effects of halogenated agents delivered through devices used for inhaled ICU sedation.

We describe a model of hydrochloric acid-induced acute respiratory distress syndrome (ARDS) in piglets receiving sedation with halogenated agents, isoflurane and sevoflurane, through a device used for inhaled intensive care sedation. This model can be used to investigate the biological mechanisms of halogenated agents on lung injury and repair.

Acute respiratory distress syndrome (ARDS) is a common cause of hypoxemic respiratory failure and death in critically ill patients, and there is an urgent ...

Endotracheal Intubation of Rabbits Using a Polypropylene Guide Catheter

Endotracheal intubation in rabbits can be challenging due to their unusual anatomy. Achieving a patent airway during anesthesia is critical for the avoidance of airway obstruction, prevention of gastric tympany, and to allow ventilatory support. Due to the difficulty of intubation, alternative methods such as the use of laryngeal mask airways or laryngeal tubes have been explored. However, these methods do not result in direct access to the trachea and thus may present a risk for development of complications. In addition, lack of direct intubation of the trachea can result in personnel exposure to waste anesthetic gases. Numerous methods for endotracheal intubation have been described, including blind placement, use of a fiberoptic laryngoscope or endoscope, and cricoid placement. Despite these numerous publications, many still struggle to achieve success. Here we provide a detailed description of an intubation technique that can be taught with minimal training with a short time to proficiency. Briefly, after administration of injectable anesthesia and proper positioning of the rabbit, a polypropylene catheter is placed into the trachea by direct visualization using a laryngoscope. The catheter is then used as a guide to direct the endotracheal tube into the trachea. This method allows for intubation without the need for expensive equipment and can be performed by a single individual without the need for an assistant. In conclusion, this technique can be easily taught and performed at very little cost in any clinical or research setting.

Endotracheal intubation in rabbits is challenging due to their unusual anatomy. Here we present a technique for direct intubation of the trachea using a polypropylene catheter as a guide. This method utilizes relatively inexpensive supplies, requires minimal training, and can be easily performed in any clinical setting.

Endotracheal intubation in rabbits can be challenging due to their unusual anatomy. Achieving a patent airway during anesthesia is critical for the ...

Biology

Description of a Swine Infant Model of Volume-Controlled Hemorrhagic Shock

Hemorrhagic shock is a leading cause of morbidity and mortality in pediatric patients. Interpretation of the clinical indicators validated in adults to guide resuscitation and comparison between different therapies is difficult in children due to the inherent heterogeneity of this population. As a result, compared to adults, appropriate management of pediatric hemorrhagic shock is still not well established. In addition, the scarcity of pediatric patients with hemorrhagic shock precludes the development of clinically relevant studies. For this reason, an experimental pediatric animal model is necessary to study the effects of hemorrhage in children as well as their response to different therapies. We present an infant animal model of volume-controlled hemorrhagic shock in anesthetized young pigs. Hemorrhage is induced by withdrawing a previously calculated blood volume, and the pig is subsequently monitored and resuscitated with different therapies. Here, we describe a precise and highly reproducible model of hemorrhagic shock in immature swine. The model yields hemodynamic data that characterizes compensatory mechanisms that are activated in response to severe hemorrhage.

This article aims to provide researchers with a detailed and accessible guide to set up an infant porcine model of hemorrhagic shock.

Hemorrhagic shock is a leading cause of morbidity and mortality in pediatric patients. Interpretation of the clinical indicators validated in adults to ...

Tracheotomy-Based Endotracheal Intubation Protocol for Non-Survival Rat Models

Endotracheal Intubation via Tracheotomy and Subsequent Thoracotomy in Rats for Non-Survival Applications

Endotracheal intubation and subsequent ventilation are often basic requirements for translational research in rat models for various interventions that require controlled or high ventilation pressures or access to the thoracic cavity and organs. Conventional endoorotracheal intubation using the anatomically existing route through the mouth is well suited for survival experiments. However, this procedure poses some challenges, including generally higher levels of the required experience and technical skill, more advanced equipment, and greater time effort with relevant intubation failure rates and complications such as tracheal perforation, temporary systemic hypooxygenation, and relevant aerial leakage.
This manuscript, therefore, presents a detailed step-by-step protocol for endotracheal intubation through tracheotomy in non-survival rat models when guaranteed intubation success, constant oxygenation levels, high ventilation pressures, or open thoracotomy are required.
The protocol emphasizes the importance of meticulous surgical technique to ensure consistent and reliable outcomes, especially for researchers who are inexperienced or lack routine in the technique of endoorotracheal intubation via direct laryngoscopy. This procedure is, therefore, expected to minimize animal suffering and unnecessary animal losses.

Here we introduce a standardized procedure for endotracheal intubation via tracheotomy followed by thoracotomy in rats, aimed at enhancing the precision and reproducibility of non-survival applications requiring invasive ventilation and exposure of thoracic organs in in vivo rat models.

Endotracheal intubation and subsequent ventilation are often basic requirements for translational research in rat models for various interventions that ...

Awake Intubation in Difficult Airways: A Flexible Video Laryngoscope Method

The Flexible Rhino-Laryngoscope for Awake Nasotracheal Intubation

Difficulties or failures in securing the airway still occur and can lead to permanent disabilities and mortality. Patients with head and neck pathologies obstructing airway access are at risk of airway management failure once they lose spontaneous respiration. Awake flexible scope intubation is considered the gold standard for controlling the airway in such patients. Following a feasibility trial involving 25 patients with challenging airways, this article presents a step-by-step protocol for awake nasotracheal intubation using a flexible video rhino-laryngoscope, which is significantly shorter than conventional intubating flexible scopes. The flexible video laryngoscope only exceeds the intubating tube length by a few centimeters, allowing the tube to closely follow the flexible scope during the procedure. Once the scope reaches the pharynx, it can be easily manipulated with one hand, enabling the operator to focus on the safe advancement of the scope-intubating tube assembly through the glottis. Based on previous results and experience gained, this article highlights the potential benefits of the technique: the opportunity for a minimally invasive "quick look" preoperatively to establish a final management plan, a more convenient and safer tool for navigating distorted anatomy with a lower chance of intubating tube impingement and airway injury, and a fast and smooth procedure resulting in improved patient satisfaction.

Author Spotlight: Advancing Awake Nasotracheal Intubation with Flexible Video Rhino-Laryngoscopes

Presented here is a protocol for awake nasotracheal intubation using a flexible rhino-laryngoscope with a 300 mm working length. As this tool is minimally invasive and easy to manipulate, awake intubation performed with a flexible rhino-laryngoscope is well-tolerated, fast, and safe for patients with difficult airways.

Difficulties or failures in securing the airway still occur and can lead to permanent disabilities and mortality. Patients with head and neck pathologies ...

Swine Axillary Artery Injury Model for Testing Pre-Hospital Hemostatic Products

A New Hybrid Quantitative Evaluation Model for Axillary Junctional Hemorrhage in Swine

In this study, we developed and validated a hybrid quantitative model for simulating upper extremity junctional hemorrhage in swine, aiming to advance the development of pre-hospital hemostatic products. Utilizing 12 healthy 8-month-old male Yorkshire swine, we demonstrated the feasibility of a swine axillary artery injury model for evaluating hemostatic efficacy. Animals were divided into three groups to undergo volume-controlled hemorrhage (VCH), mimicking Class I-III hemorrhagic shock by withdrawing blood at different rates. Subsequent external compression was applied using a novel device consisting of a mechanical arm and an inflatable hemostatic balloon, achieving controlled pressure to enhance clot formation. Hemodynamic parameters, including heart rate and blood pressure, were continuously monitored, highlighting the impact of controlled hemorrhage and external compression on physiological responses. The findings suggest that the combination of VCH with targeted external compression effectively simulates clinical scenarios of axillary artery injury, providing a valuable model for testing hemostatic interventions in a controlled, standardized manner. This study underscores the potential of the model in facilitating the development and evaluation of new hemostatic agents and devices for managing junctional hemorrhages.

This study presents a hybrid quantitative model for axillary junctional hemorrhage in swine, enhancing pre-hospital hemostatic intervention evaluation.

In this study, we developed and validated a hybrid quantitative model for simulating upper extremity junctional hemorrhage in swine, aiming to advance the ...

Tracheal Intubation for Mechanical Ventilation: A Procedure to Insert Endotracheal Tube in Trachea of Rabbit Model

Source: Marger, L. et al, <a href="https://jove.unicartagenaproxy.elogim.com/v/59976">Calvarial Model of Bone Augmentation in Rabbit for Assessment of Bone Growth and Neovascularization in Bone Substitution Materials.</a> J. Vis. Exp. (2019)
In this video, we demonstrate the tracheal intubation &#8212; an invasive procedure for insertion of an endotracheal tube through the mouth in a rabbit model. This procedure allows for mechanical ventilation of the lungs.

Endotracheal Intubation Using a Flexible Intubation Endoscope as a Standardized Model for Safe Airway Management in Swine

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Endotracheal Intubation in Mice via Direct Laryngoscopy Using an Otoscope

Standardized Model of Ventricular Fibrillation and Advanced Cardiac Life Support in Swine

The Rigid Tube as an Alternative in Controlling the Problematic Airway

Halogenated Agent Delivery in Porcine Model of Acute Respiratory Distress Syndrome via an Intensive Care Unit Type Device

Endotracheal Intubation of Rabbits Using a Polypropylene Guide Catheter

Description of a Swine Infant Model of Volume-Controlled Hemorrhagic Shock

Endotracheal Intubation via Tracheotomy and Subsequent Thoracotomy in Rats for Non-Survival Applications

The Flexible Rhino-Laryngoscope for Awake Nasotracheal Intubation

A New Hybrid Quantitative Evaluation Model for Axillary Junctional Hemorrhage in Swine

Intubacja tchawicy w celu wentylacji mechanicznej: procedura wprowadzania rurki dotchawiczej do tchawicy modelu królika