The authors thank Lucia Rosas, Lauren Doolittle, Lisa Joseph and Lindsey Ferguson for their technical assistance and the University Laboratory Animal Resources for their animal care support. This work is funded by NIH T35OD010977 and R01-HL102469.

All animal activities described here have been approved by the Institutional Animal Care and Use Committee (IACUC) of The Ohio State University and were conducted in AAALAC-accredited facilities.
1. Procedure Preparation
<ol>
	<li>Construct the intubation platform. To achieve the appropriate platform slope, use a three-inch (7.6 cm) 3-ring binder. Fold a 15&#8722;20 cm length of 3-0 silk or other thread material in half and adhere the ends of the thread to the top of the inclined platform with tape to create a suspension loop (Figure 1).</li>
	<li>Select a cannula of the appropriate size and length. 
	NOTE: For a 20&#8722;30 g mouse, a 1&#8722;1.5 inch (2.5&#8722;3.8 cm) long catheter up to 18 G can be used. For this study, 18 week-old female BALB/c and 10-week-old C57BL/6 mice (n = 3 of each strain) were used. An opaque white catheter sheath provides the best transcutaneous visualization.</li>
	<li>Cut a bevel at the distal tip of the catheter and smooth the cut surface with abrasive paper to create a rounded bevel tip. Gently create a slight bend in the cannula approximately 1 cm from the bevel (Figure 2). 
	NOTE: A new catheter should be used for each mouse.</li>
	<li>Anesthetize the mouse with ketamine (5.4 mg/g body weight) and xylazine (16 &#181;g/g body weight) administered intraperitoneally.&#160; Apply sterile ophthalimic ointment to the eyes. 
	NOTE: Proper anesthetic depth is achieved by lack of response of the mouse to a firm toe pinch.</li>
	<li>Suspend the mouse in a supine position on the intubation platform by hooking the upper incisors around the silk thread at the top of the angled surface (Figure 3). Once the mouse is squarely positioned in dorsal recumbency, gently grasp the base of the tail and retract the tail towards the table. Place a piece of tape over the base of tail to secure the mouse.</li>
	<li>Apply depilatory cream (Table of Materials) to the ventral cervical region for 30&#8722;45 s then remove all depilatory cream from the cervical region using a dry gauze. Repeat application process if needed. Thoroughly rinse the skin with saline or distilled water to remove any residue then wipe dry.</li>
</ol>
2. Intubation Procedure
<ol>
	<li>Use straight, flat forceps in the nondominant hand to gently retract the tongue in a manner that sufficiently opens the mouth for introduction of the cannula. 
	NOTE: Rat tooth forceps should not be used as this will damage the tongue.</li>
	<li>With the dominant hand, advance the cannula into the mouth such that the end that is distal to the slight bend is against the roof of the subject&#8217;s mouth.</li>
	<li>Release the tongue and slide the flat edge of the closed forceps caudally along the ventral neck until the manubrium is reached. This motion laterally displaces the salivary glands and flattens the muscle covering the trachea. The trachea appears transcutaneously as a white line (Figure 3A). If necessary, rotate the forceps in a craniodorsal direction while maintaining tension on the skin in a caudal direction to cause the laterally displaced salivary glands to peak. This maneuver creates more contrast around the trachea (Figure 3B). 
	NOTE: Avoid excessive force on the ventral neck as it can collapse the trachea and impair breathing.</li>
	<li>Advance the cannula while simultaneously angling the distal tip of the cannula ventrally by supination of the dominant hand with simultaneous flexion of the wrist.</li>
	<li>The proper placement of the cannula is indicated by visualization of the opaque cannula in the trachea (Figure 4B,D). If the cannula has been advanced past the level of the origin of the masseter muscle and visualization of the cannula in the trachea has not been confirmed, retract the cannula and reattempt the maneuver.</li>
	<li>Confirm proper cannula placement by connecting a lung inflation bulb to the cannula and observing thoracic expansion with concurrent depression of the device.</li>
	<li>Without displacing the cannula, carefully unhook the incisors of the mouse from the intubation platform. Move the mouse to a horizontal platform (Table of Materials) and insert the cannula to the adaptor on the ventilator. Following the deep inflation, ventilate the mouse for 60 s then measure respiratory resistance.</li>
</ol>
3. Recovery
<ol>
	<li>Once the procedure is complete, move the mouse to a warmed platform. Provide constant stimulation via light toe or tail pinches to encourage spontaneous respiration.</li>
	<li>Extubation can occur when the mouse just begins to chew. Grasp the cannula at the level of the hub and gently pull the tube cranially and away from the mouse until the cannula is completely removed from the subject&#8217;s mouth. 
	NOTE: It is preferable to provide airway support with the rigid cannula for as long as possible during the recovery process.</li>
	<li>Once extubated, transfer the mouse to a clean recovery cage with heat support. Continuously monitor the mouse until it is fully ambulatory, and recovery is complete.</li>
</ol>

<ol>
	<li>Spoelstra, E. N., 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=A+novel+and+simple+method+for+endotracheal+intubation+of+mice.">A novel and simple method for endotracheal intubation of mice.</a> Laboratory Animals. 41 (1), 128-135 (2007).</li><li>Rivera, B., Miller, S. R., Brown, E. M., Price, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Method+for+Endotracheal+Intubation+of+Mice+and+Rats+Used+in+Imaging+Studies.">A Novel Method for Endotracheal Intubation of Mice and Rats Used in Imaging Studies.</a> Contemporary Topics in Laboratory Animal Science. 44 (2), 52-55 (2005).</li><li>Sparrowe, J., Jimenez, M., Rullas, J., Martinez, A. E., Ferrer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Refined+Intratracheal+Intubation+Technique+in+the+Mouse,+Complete+Protocol+Description+for+Lower+Airway+Models.">Refined Intratracheal Intubation Technique in the Mouse, Complete Protocol Description for Lower Airway Models.</a> Global Journal of Animal Scientific Research. 3 (2), 363-369 (2015).</li><li>Deyo, D. J., Wei, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Method+of+Intubation+and+Ventilation+in+Mice.">A Novel Method of Intubation and Ventilation in Mice.</a> Anesthesia &amp; Analgesia. 88 (2), 179 (1999).</li><li>Vergari, A., 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=A+new+method+of+orotracheal+intubation+in+mice.">A new method of orotracheal intubation in mice.</a> European Review for Medical and Pharmacological Sciences. 8 (3), 103-106 (2004).</li><li>Brown, R. H., Walters, D. M., Greenberg, R. S., Mitzner, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+of+endotracheal+intubation+and+pulmonary+functional+assessment+for+repeated+studies+in+mice.">A method of endotracheal intubation and pulmonary functional assessment for repeated studies in mice.</a> Journal of Applied Physiology. 87 (6), 2362-2365 (1999).</li><li>Das, S., MacDonald, K., Chang, H. S., Mitzner, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Simple+Method+of+Mouse+Lung+Intubation.">A Simple Method of Mouse Lung Intubation.</a> Journal of Visualized Experiments. (73), e50318 (2013).</li><li>Limjunyawong, N., Mock, J., Mitzner, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Instillation+and+Fixation+Methods+Useful+in+Mouse+Lung+Cancer+Research.">Instillation and Fixation Methods Useful in Mouse Lung Cancer Research.</a> Journal of Visualized Experiments. (102), e52964 (2015).</li><li>Qin, W., Baran, U., Wang, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphatic+response+to+depilation-induced+inflammation+assessed+with+label-free+optical+lymphangiography.">Lymphatic response to depilation-induced inflammation assessed with label-free optical lymphangiography.</a> Lasers in Surgery and Medicine. 47 (8), 669-676 (2015).</li><li>McGovern, T. K., Robichaud, A., Fereydoonzad, L., Schuessler, T. F., Martin, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+Respiratory+System+Mechanics+in+Mice+using+the+Forced+Oscillation+Technique.">Evaluation of Respiratory System Mechanics in Mice using the Forced Oscillation Technique.</a> Journal of Visualized Experiments. (75), e50107 (2013).</li></ol>

The authors have nothing to disclose.

Intubation using the transcutaneous tracheal visualization technique offers a refined approach to the standard skin incision method. With special attention to several key steps, intubation can be easily and quickly achieved. The animal must be placed squarely in dorsal recumbency on the intubation platform with the mouse secured in gentle retraction. This will extend the animal into vertical alignment and proper positioning for intubation. In addition, the depilatory cream should not remain in contact with the animal&#82...

The laboratory mouse is a common animal model for human respiratory disease. Thus, there are several published methods for mouse intubation for the purpose of both instillation of treatments and measurement of respiratory mechanics. Most of the described procedures require visualization of the glottis through the oral cavity with specialized equipment such as a laryngoscope or fiber-optic light source1,2,3,4,5,6,7. However, this can be difficult when a relatively large cannula is required, as it can obscure the view of the researcher. Limjunyawong et al.8 have addressed this concern with a method of intubation in which a small cutaneous incision is made along the midline of the ventral neck allowing for visualization of the trachea. Following the procedure, the incision is closed with tissue adhesive.
For studies requiring frequent repeated intubations, successive incising and closure of this site requires debridement of the skin margins and tissue trauma to the ventral neck. The purpose of the transcutaneous tracheal visualization approach to oral intubation is to provide a refined, noninvasive technique specifically suitable for repeated intubation studies as well as single intubation events in mice.

<table>
	<tbody>
		<tr>
			<td>18Gx1 1/4&#34; intravenous catheter, Safelet</td>
			<td>Fisher Scientific</td>
			<td>#14-841-14</td>
			<td>Cannula for intubation</td>
		</tr>
		<tr>
			<td>70% ethanol, 10L</td>
			<td>Fisher Scientific</td>
			<td>25467025</td>
			<td>Cleaning cannula</td>
		</tr>
		<tr>
			<td>Abrasive paper (sandpaper)</td>
			<td>Porter-Cable</td>
			<td>74001201</td>
			<td>Cannula preparation</td>
		</tr>
		<tr>
			<td>AnaSed (xylazine sterile solution) injection (100 mg/ml)</td>
			<td>Akorn Animal Health</td>
			<td>NDC# 59399-111-50</td>
			<td>Anesthesia</td>
		</tr>
		<tr>
			<td>Blue labeling tape (0.5 in x 14 yds)</td>
			<td>Fisher Scientific</td>
			<td>15966</td>
			<td>Restraint on intubation platform</td>
		</tr>
		<tr>
			<td>Braided silk suture without needle, nonsterile, (3-0)</td>
			<td>Henry Schein</td>
			<td>Item #1007842</td>
			<td>Intubation platform</td>
		</tr>
		<tr>
			<td>Deltaphase Isothermal Pad</td>
			<td>Braintree Scientific</td>
			<td>39DP</td>
			<td>Mouse thermoregulation and recovery</td>
		</tr>
		<tr>
			<td>Deltaphase Operating Board</td>
			<td>Braintree Scientific</td>
			<td>39OP</td>
			<td>Mouse recovery (prior to extubation)</td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>ThermoFisher</td>
			<td>15230253</td>
			<td>Cleaning mouse following depilation</td>
		</tr>
		<tr>
			<td>Eye Scissors, angled, sharp/sharp</td>
			<td>Harvard Apparatus</td>
			<td>72-8437</td>
			<td>Cannula preparation</td>
		</tr>
		<tr>
			<td>FlexiVent (FX Module 2)</td>
			<td>Scireq</td>
			<td>N/A</td>
			<td>Record lung function data (not required to perform procedure, used in this study to validate procedure)</td>
		</tr>
		<tr>
			<td>Gauze sponges</td>
			<td>Fisher scientific</td>
			<td>13-761-52</td>
			<td>Hair removal</td>
		</tr>
		<tr>
			<td>Heavy-Duty 3&#34; 3-Ring View Binders</td>
			<td>Staples</td>
			<td>24690CT</td>
			<td>Intubation platform</td>
		</tr>
		<tr>
			<td>Instat Software</td>
			<td>Graphpad</td>
			<td>N/A</td>
			<td>Statistical analysis software</td>
		</tr>
		<tr>
			<td>Insulin syringe (0.5 cc, U100)</td>
			<td>Fisher Scientific</td>
			<td>329461</td>
			<td>Anesthesia administration</td>
		</tr>
		<tr>
			<td>Ketamine HCl Injection, USP (100 mg/ml)</td>
			<td>Llyod Laoratories</td>
			<td>List No. 4871</td>
			<td>Anesthesia</td>
		</tr>
		<tr>
			<td>Lung inflation bulb</td>
			<td>Harvard Apparatus</td>
			<td>72-9083</td>
			<td>Confirm cannula placement</td>
		</tr>
		<tr>
			<td>Micro Forceps, Curved, Smooth</td>
			<td>Harvard Apparatus</td>
			<td>72-0445</td>
			<td>Retract tongue and create tension on neck for cannula visualization</td>
		</tr>
		<tr>
			<td>Nair (hair removal lotion), 9 oz bottle</td>
			<td>Church &#38; Dwight</td>
			<td>42010440</td>
			<td>Hair removal</td>
		</tr>
		<tr>
			<td>Sterile saline (0.9%), 10 ml</td>
			<td>Fisher Scientific</td>
			<td>NC9054335</td>
			<td>Anesthesia, cleaning skin following hair removal</td>
		</tr>
	</tbody>
</table>

repeated orotracheal intubation in mice

The literature describes several methods for mouse intubation that either require visualization of the glottis through the oral cavity or incision in the ventral neck for direct confirmation of cannula placement in the trachea. The relative difficulty or the tissue trauma induced to the subject by such procedures can be an impediment to an investigator&#8217;s ability to perform longitudinal studies. This article illustrates a technique in which physical manipulation of the mouse following the use of a depilatory to remove hair from the ventral neck permits transcutaneous visualization of the trachea for orotracheal intubation regardless of degree of skin pigmentation. This method is innocuous to the subject and easily achieved with a limited understanding of murine anatomy. This refined approach facilitates repeated intubation, which may be necessary for monitoring progression of disease or instillation of treatments. Using this method may result in a reduction of the number of animals and technical skill required to measure lung function in mouse models of respiratory disease.

Serial monitoring of baseline pulmonary function 
Eighteen-week-old female BALB/c and 10-week-old C57BL/6 mice (n = 3 of each strain) were intubated using the described method on day 0, 3, 10, and 17. Following intubation on each day, the subject was connected to a mechanical ventilator supplied with 100% oxygen (Table of Materials). Respiratory resistance (Rrs) was measured using the forced oscillation technique for 60 s following a deep inflation to 25 cm H2O held for 5...

Watch this Scientific Journal Video about Repeated Orotracheal Intubation in Mice at JoVE.com

Repeated Orotracheal Intubation in Mice

The goal of this article is to describe a refined method of intubation of the laboratory mouse. The method is noninvasive and, therefore, ideal for studies that require serial monitoring of respiratory function and/or instillation of treatments into the lung.

The literature describes several methods for mouse intubation that either require visualization of the glottis through the oral cavity or incision in the ...

Research

JoVE Journal

Medicine

15.7K Views.  The Ohio State University. The goal of this article is to describe a refined method of intubation of the laboratory mouse. The method is noninvasive and, therefore, ideal for studies that require serial monitoring of respiratory function and/or instillation of treatments into the lung.

Video: Repeated Orotracheal Intubation in Mice

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 ...

Guidelines for Elective Pediatric Fiberoptic Intubation

Fiberoptic intubation in pediatric patients is often required especially in difficult airways of syndromic patients i.e. Pierre Robin Syndrome. Small babies will desaturate very quickly if ventilation is interrupted mainly to high metabolic rate. We describe guidelines to perform a safe fiberoptic intubation while maintaining spontaneous breathing throughout the procedure. Steps requiring the use of propofol pump, fentanyl, glycopyrrolate, red rubber catheter, metal insuflation hook, afrin, lubricant and lidocaine spray are shown.

We describe guidelines to perform a safe and efficient elective fiberoptic intubation in pediatric patients while maintaining spontaneous ventilation.

Fiberoptic intubation in pediatric patients is often required especially in difficult airways of syndromic patients i.e. Pierre Robin Syndrome. Small ...

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 ...

A Simple Method of Mouse Lung Intubation

A simple procedure to intubate mice for pulmonary function measurements would have several advantages in longitudinal studies with limited numbers or expensive animal. One of the reasons that this is not done more routinely is that it is relatively difficult, despite there being several published studies that describe ways to achieve it. In this paper we demonstrate a procedure that eliminates one of the major hurdles associated with this intubation, that of visualizing the trachea during the entire time of intubation. The approach uses a 0.5 mm fiberoptic light source that serves as an introducer to direct the intubation cannula into the mouse trachea. We show that it is possible to use this procedure to measure lung mechanics in individual mice over a time course of at least several weeks. The technique can be set up with relatively little expense and expertise, and it can be routinely accomplished with relatively little training. This should make it possible for any laboratory to routinely carry out this intubation, thereby allowing longitudinal studies in individual mice, thereby minimizing the number of mice needed and increasing the statistical power by using each mouse as its own control.

This paper describes a striaghforward and efficient method of intubating mice for pulmonary function measurements or pulmonary instillation, that allows the mice to recover and be studied at later times. The procedure involves an inexpensive fiberoptic light source that directly illuminates the trachea.

A  simple procedure to intubate mice for pulmonary function measurements would  have several advantages in longitudinal studies with limited numbers or  ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

An Improved Method for Rapid Intubation of the Trachea in Mice

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity is a commonly used model to study both acute lung injury and fibrosis, and multiple methods have been developed for administering bleomycin (and other toxic agents) into the lungs. However, many of these approaches, such as transtracheal instillation, have inherent drawbacks, including the need for strong anesthetics and survival surgery. This paper reports a quick, reproducible method of intratracheal intubation that involves mild inhaled anesthesia, visualization of the trachea, and the use of a surrogate spirometer to confirm exposure. As a proof of concept, 8-12 week old C57BL/6 mice were administered either 2.0 U/kg of bleomycin or an equivalent volume of PBS, and both damage and fibrotic endpoints were measured post-exposure. This procedure allows researchers to treat a large cohort of mice in a relatively short period with little expense and minimal post-procedure care.

This article presents a rapid and simple method for administering bleomycin directly into the mouse trachea via intubation. Key advantages of this method are that it is highly reproducible, easy to master, and does not require specialized equipment or lengthy recovery times.

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity ...

Repeated Measurement of Respiratory Muscle Activity and Ventilation in Mouse Models of Neuromuscular Disease

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated measurements over weeks or months of accessory respiratory muscle activity while simultaneously measuring ventilation in a non-anesthetized, freely behaving mouse. The technique includes the surgical implantation of a radio transmitter and the insertion of electrode leads into the scalene and trapezius muscles to measure the electromyogram activity of these inspiratory muscles. Ventilation is measured by whole-body plethysmography, and animal movement is assessed by video and is synchronized with electromyogram activity. Measurements of muscle activity and ventilation in a mouse model of amyotrophic lateral sclerosis are presented to show how this tool can be used to investigate how respiratory muscle activity changes over time and to assess the impact of muscle activity on ventilation. The described methods can easily be adapted to measure the activity of other muscles or to assess accessory respiratory muscle activity in additional mouse models of disease or injury.

This paper introduces a method for repeated measurements of ventilation and respiratory muscle activity in a freely behaving amyotrophic lateral sclerosis (ALS) mouse model throughout disease progression with whole-body plethysmography and electromyography via an implanted telemetry device.

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated ...

Generation of a Chronic Obstructive Pulmonary Disease Model in Mice by Repeated Ozone Exposure

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and lung parenchymal destruction. It has a very high incidence in aging populations. The current conventional therapies for COPD focus mainly on symptom-modifying drugs; thus, the development of new therapies is urgently needed. Qualified animal models of COPD could help to characterize the underlying mechanisms and can be used for new drug screening. Current COPD models, such as lipopolysaccharide (LPS) or the porcine pancreatic elastase (PPE)-induced emphysema model, generate COPD-like lesions in the lungs and airways but do not otherwise resemble the pathogenesis of human COPD. A cigarette smoke (CS)-induced model remains one of the most popular because it not only simulates COPD-like lesions in the respiratory system, but it is also based on one of the main hazardous materials that causes COPD in humans. However, the time-consuming and labor-intensive aspects of the CS-induced model dramatically limit its application in new drug screening. In this study, we successfully generated a new COPD model by exposing mice to high levels of ozone. This model demonstrated the following: 1) decreased forced expiratory volume 25, 50, and 75/forced vital capacity (FEV25/FVC, FEV50/FVC, and FEV75/FVC), indicating the deterioration of lung function; 2) enlarged lung alveoli, with lung parenchymal destruction; 3) reduced fatigue time and distance; and 4) increased inflammation. Taken together, these data demonstrate that the ozone exposure (OE) model is a reliable animal model that is similar to humans because ozone overexposure is one of the etiological factors of COPD. Additionally, it only took 6 - 8 weeks, based on our previous work, to create an OE model, whereas it requires 3 - 12 months to induce the cigarette smoke model, indicating that the OE model might be a good choice for COPD research.

This study describes the successful generation of a new chronic obstructive pulmonary disease (COPD) animal model by repeatedly exposing mice to high concentrations of ozone.

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and lung parenchymal destruction. It has a very high ...

Blind Endotracheal Intubation in Neonatal Rabbits

The newborn rabbit is a useful animal model for various pathologies and procedures. Airway management of the rabbit is complex due to its anatomical characteristics, which is further complicated in the case of the newborn. Of the different methods of advanced airway management, endotracheal intubation is less aggressive than tracheostomy, and is more feasible than supraglottic management given the lack of supraglottic devices of such a small size. As direct glottis visualization is very difficult in animals this size, this blind intubation model is presented as an effective alternative, especially for experiments requiring prolonged anesthesia. Using this method, we performed blind intubations with a 90% success rate.

We describe a technique of endotracheal intubation in newborn rabbits after esophageal catheterization with a gastric tube.

The newborn rabbit is a useful animal model for various pathologies and procedures. Airway management of the rabbit is complex due to its anatomical ...

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.

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 ...