Name: A Structured Approach to Extubation in Mechanically Ventilated Rats (Video) | JoVE Journal
Uploaded: 2025-07-18T16:20:00.000+00:00
Duration: 5 min 5 s
Description: Learn a structured extubation protocol in mechanically ventilated rats to simulate clinical weaning and reduce complications. This method improves the reliability of studying ventilator-induced brain and diaphragm injuries.

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The study focused on post-extubation behavioral testing and was approved by the Animal Experiments and Experimental Animal Welfare Committee of Capital Medical University (No. AEEI-2024-391). All rats aged 8 weeks (SD, male, 200-250 g) were acclimatized in the animal facility at Capital Medical University for 3 days prior to the experiment. The rat was housed under a controlled environment, including a 12-h light/dark cycle beginning at 8:00 AM, a temperature of 25 &#176;C &#177; 1 &#176;C, and humidity maintained at 50% &#177; 10 %. Food and water were provided ad libitum. All procedures involving anesthesia, suctioning, and blood handling were performed with appropriate safety measures, including the use of personal protective equipment, sterile techniques, and adherence to institutional biosafety protocols. All procedures were performed in compliance with the ARRIVE guidelines. All equipment used in the current study is presented in Figure 1. The list of reagents and the equipment used are provided in the Table of Materials.
1. Video laryngoscopy-assisted oral intubation
<ol>
	<li>Prepare the intubation device.
	<ol>
		<li>Use a custom-modified intubation device, adapted from an earwax removal device (scoop diameter 5.5 mm, curved into a tongue depressor). This device is equipped with a light source and camera, Bluetooth-linked to a smartphone for real-time visualization (Figure 2A).</li>
	</ol>
	</li>
	<li>Select an endotracheal tube.
	<ol>
		<li>Choose a 16-G endotracheal tube based on the rat&#39;s weight.</li>
	</ol>
	</li>
	<li>Induce anesthesia (following institutionally approved protocols).
	<ol>
		<li>Inject propofol (2 mg/100 g) via the tail vein. Confirm anesthesia by verifying the absence of visual and toe pinch responses. Monitor the distal skin color as an indicator of oxygenation status.</li>
	</ol>
	</li>
	<li>Position the rat.
	<ol>
		<li>Secure the anesthetized rat on a small animal table. Fix limbs and incisors, and maintain body temperature at 37-38 &#176;C using a small animal heating blanket.</li>
	</ol>
	</li>
	<li>Perform intubation.
	<ol>
		<li>Gently pull the tongue to the right oral corner. Insert the intubation device at the base of the tongue and advance it toward the epiglottis.</li>
		<li>Lift the device tip to expose the glottis. Insert the endotracheal tube during inhalation (Figure 2-C).Once intubated, the rat will be connected to the ventilator.</li>
	</ol>
	</li>
</ol>
2. Mechanical ventilation
<ol>
	<li>Connect the oxygen concentrator.
	<ol>
		<li>Adjust the appropriate oxygen concentration and connect with the ventilator (usually 80%).</li>
	</ol>
	</li>
	<li>Set ventilator parameters.
	<ol>
		<li>Ventilate the rat for 6 h using a small animal ventilator with lung-protective settings: tidal volume: 4-6 mL/kg, PEEP: 0 cmH2O.</li>
	</ol>
	</li>
	<li>Maintain anesthesia: Infuse propofol (4 mg/kg/h) via a syringe pump.</li>
	<li>Monitor blood gases.
	<ol>
		<li>Test arterial blood gases every 3 h using a blood gas analyzer. Continuously monitor the distal skin color between blood gas analyses as an indicator of oxygenation status.</li>
	</ol>
	</li>
</ol>
3. Airway pressure endpoint control (APEC) extubation procedure
NOTE: After the planned duration of mechanical ventilation is completed, proceed with the four-step extubation protocol: (1) Approaching weaning, (2) Preparing extubation, (3) Executing extubation, and (3) Caring post-extubation (Figure 3). This systematic approach ensures a smooth transition to spontaneous breathing while minimizing extubation-related complications and preserving the integrity of the experimental model.
<ol>
	<li>Approaching weaning
	<ol>
		<li>Reduce propofol infusion: Decrease the propofol infusion rate by 50% to allow diaphragm reactivation while minimizing limb and head movements.</li>
		<li>Assess readiness for weaning: Check the following parameters before disconnecting the ventilator - Respiratory rate: 60-70 breaths/min; Chest displacement: &#8805;1 mm (measure using a steel needle placed on the xiphoid process); PaCO2: 35-45 mmHg; pH: 7.35-7.45; Presence of whisker and tongue reflexes (optional). 
		NOTE: The whisker and tongue reflexes were defined as binary indicators (absent or present). The whisker reflex refers to the involuntary movement or twitching of the vibrissae in response to light tactile stimulation. The tongue reflex was characterized by tongue withdrawal or movement upon gentle stimulation.</li>
		<li>Disconnect ventilator: Disconnect the ventilator once all criteria are met, and proceed to prepare the rat for extubation.</li>
	</ol>
	</li>
	<li>Preparing for extubation
	<ol>
		<li>Ensure oxygenation: Use a self-made face mask to maintain adequate oxygenation (usually 80%), and use skin color as an indicator of oxygenation status.</li>
		<li>Clear airway secretions: Use a self-made suction device (shortened epidural catheter [~5.5 cm] connected to a 10 mL syringe). Control suction speed at ~2 mL/s for 3-4 s per session.</li>
		<li>Following adequate preparation and airway clearance, the procedure proceeds to the execution of extubation. 
		NOTE: Typical secretion volume is &#60;0.5 mL per suction. Suction is performed every 30 min during MV to minimize accumulation. At the time of extubation, the suction frequency was commonly 5-8 times, with an estimated amount of 2-4 mL in total.</li>
	</ol>
	</li>
	<li>Executing extubation
	<ol>
		<li>Maintain sedation: Keep propofol at half-dose to prevent agitation during extubation.</li>
		<li>Remove endotracheal tube: Use A two-handed technique and stabilize the rat&#39;s head with the left index finger and thumb. Gently remove the tube with the right index finger and thumb.</li>
		<li>Discontinue propofol: Stop propofol infusion immediately after extubation. 
		NOTE: Successful extubation should not result in hypoxemia or hypercapnia. And after successful extubation, diligent post-extubation care is essential.</li>
	</ol>
	</li>
	<li>Post-extubation care
	<ol>
		<li>Monitor vital signs: Monitor respiratory rate, inspiratory amplitude, and distal skin color.</li>
		<li>Provide oxygenation: Use a self-made face mask to ensure a sufficient oxygen supply (usually ~80%).</li>
		<li>Prepare for re-intubation: Keep all intubation devices (Figure 1) on hand and ready for immediate use if needed. 
		NOTE: Average observation time until righting reflex restoration is 48.5 min &#177; 10.4 min. Arterial blood gas analysis was performed at a median of 20 min, with PaO2&#160;of 73.2 mmHg &#8239;&#177;&#8239;4.6 mmHg and PaCO2&#160;of 48.3&#8239; mmHg &#177;&#8239;3.6 mmHg.</li>
	</ol>
	</li>
</ol>

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<li>Slutsky, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((History+of+mechanical+ventilation.+From+Vesalius+to+ventilator-induced+lung+injury%5BTitle%5D)+AND+%22Am+J+Respir+Crit+Care+Med%22%5BJournal%5D)">History of mechanical ventilation. From Vesalius to ventilator-induced lung injury.</a> Am J Respir Crit Care Med. 191 (10), 1106-1115 (2015).</li>
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<li>Shi, Z. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Expiratory+muscle+dysfunction+in+critically+ill+patients%3A+Towards+improved+understanding%5BTitle%5D)+AND+%22Intensive+Care+Med%22%5BJournal%5D)">Expiratory muscle dysfunction in critically ill patients: Towards improved understanding.</a> Intensive Care Med. 45 (8), 1061-1071 (2019).</li>
<li>Van Den Berg, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Super-relaxed+myosins+contribute+to+respiratory+muscle+hibernation+in+mechanically+ventilated+patients%5BTitle%5D)+AND+%22Sci+Transl+Med%22%5BJournal%5D)">Super-relaxed myosins contribute to respiratory muscle hibernation in mechanically ventilated patients.</a> Sci Transl Med. 16 (758), eadg3894(2024).</li>
<li>González-López, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mechanical+ventilation+triggers+hippocampal+apoptosis+by+vagal+and+dopaminergic+pathways%5BTitle%5D)+AND+%22Am+J+Respir+Crit+Care+Med%22%5BJournal%5D)">Mechanical ventilation triggers hippocampal apoptosis by vagal and dopaminergic pathways.</a> Am J Respir Crit Care Med. 188 (6), 693-702 (2013).</li>
<li>Pun, B. T., Ely, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+importance+of+diagnosing+and+managing+ICU+delirium%5BTitle%5D)+AND+%22Chest%22%5BJournal%5D)">The importance of diagnosing and managing ICU delirium.</a> Chest. 132 (2), 624-636 (2007).</li>
<li>Trudzinski, F. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Risk+factors+for+prolonged+mechanical+ventilation+and+weaning+failure%3A+A+systematic+review%5BTitle%5D)+AND+%22Respiration%22%5BJournal%5D)">Risk factors for prolonged mechanical ventilation and weaning failure: A systematic review.</a> Respiration. 101 (10), 959-969 (2022).</li>
<li>Voiriot, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Chronic+critical+illness+and+post-intensive+care+syndrome%3A+From+pathophysiology+to+clinical+challenges%5BTitle%5D)+AND+%22Ann+Intensive+Care%22%5BJournal%5D)">Chronic critical illness and post-intensive care syndrome: From pathophysiology to clinical challenges.</a> Ann Intensive Care. 12 (1), 58(2022).</li>
<li>Brück, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Plasma+HMGB1+levels+and+physical+performance+in+ICU+survivors%5BTitle%5D)+AND+%22Acta+Anaesthesiol+Scand%22%5BJournal%5D)">Plasma HMGB1 levels and physical performance in ICU survivors.</a> Acta Anaesthesiol Scand. 65 (7), 921-927 (2021).</li>
<li>Bruells, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Influence+of+weaning+methods+on+the+diaphragm+after+mechanical+ventilation+in+a+rat+model%5BTitle%5D)+AND+%22BMC+Pulm+Med%22%5BJournal%5D)">Influence of weaning methods on the diaphragm after mechanical ventilation in a rat model.</a> BMC Pulm Med. 16 (1), 127(2016).</li>
<li>Gayan-Ramirez, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Intermittent+spontaneous+breathing+protects+the+rat+diaphragm+from+mechanical+ventilation+effects%5BTitle%5D)+AND+%22Crit+Care+Med%22%5BJournal%5D)">Intermittent spontaneous breathing protects the rat diaphragm from mechanical ventilation effects.</a> Crit Care Med. 33 (12), 2804-2809 (2005).</li>
<li>Thomas, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Time+course+of+diaphragm+function+recovery+after+controlled+mechanical+ventilation+in+rats%5BTitle%5D)+AND+%22J+Appl+Physiol%22%5BJournal%5D)">Time course of diaphragm function recovery after controlled mechanical ventilation in rats.</a> J Appl Physiol. 115 (6), 775-784 (2013).</li>
<li>Henrich, D. E., Blythe, W. R., Weissler, M. C., Pillsbury, H. C. 3rd <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Tracheotomy+and+the+intensive+care+unit+patient%5BTitle%5D)+AND+%22Laryngoscope%22%5BJournal%5D)">Tracheotomy and the intensive care unit patient.</a> Laryngoscope. 107 (7), 844-847 (1997).</li>
<li>Hsu, C. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Timing+of+tracheostomy+as+a+determinant+of+weaning+success+in+critically+ill+patients%3A+A+retrospective+study%5BTitle%5D)+AND+%22Crit+Care%22%5BJournal%5D)">Timing of tracheostomy as a determinant of weaning success in critically ill patients: A retrospective study.</a> Crit Care. 9 (1), R46-R52 (2005).</li>
<li>Gretenkord, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Coordinated+electrical+activity+in+the+olfactory+bulb+gates+the+oscillatory+entrainment+of+entorhinal+networks+in+neonatal+mice%5BTitle%5D)+AND+%22PLoS+Biol%22%5BJournal%5D)">Coordinated electrical activity in the olfactory bulb gates the oscillatory entrainment of entorhinal networks in neonatal mice.</a> PLoS Biol. 17 (1), e2006994(2019).</li>
<li>Salimi, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Disrupted+connectivity+in+the+olfactory+bulb-entorhinal+cortex-dorsal+hippocampus+circuit+is+associated+with+recognition+memory+deficit+in+Alzheimer%27s+disease+model%5BTitle%5D)+AND+%22Sci+Rep%22%5BJournal%5D)">Disrupted connectivity in the olfactory bulb-entorhinal cortex-dorsal hippocampus circuit is associated with recognition memory deficit in Alzheimer's disease model.</a> Sci Rep. 12 (1), 4394(2022).</li>
<li>Bruells, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Recovery+of+diaphragm+function+following+mechanical+ventilation+in+a+rodent+model%5BTitle%5D)+AND+%22PLoS+One%22%5BJournal%5D)">Recovery of diaphragm function following mechanical ventilation in a rodent model.</a> PLoS One. 9 (1), e87460(2014).</li>
<li>Dénervaud, V., Gremlich, S., Trummer-Menzi, E., Schittny, J. C., Roth-Kleiner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gene+expression+profile+in+newborn+rat+lungs+after+two+days+of+recovery+of+mechanical+ventilation%5BTitle%5D)+AND+%22Pediatr+Res%22%5BJournal%5D)">Gene expression profile in newborn rat lungs after two days of recovery of mechanical ventilation.</a> Pediatr Res. 78 (6), 641-649 (2015).</li>
<li>De Souza, A. B. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+in+vitro+and+in+vivo+of+hesperidin+administration+in+an+experimental+model+of+acute+lung+inflammation%5BTitle%5D)+AND+%22Free+Radic+Biol+Med%22%5BJournal%5D)">Effects in vitro and in vivo of hesperidin administration in an experimental model of acute lung inflammation.</a> Free Radic Biol Med. 180, 253-262 (2022).</li>
<li>Almeida, M. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+effects+of+different+ventilatory+modes+in+female+adult+rats+submitted+to+mechanical+ventilation%5BTitle%5D)+AND+%22Respir+Physiol+Neurobiol%22%5BJournal%5D)">The effects of different ventilatory modes in female adult rats submitted to mechanical ventilation.</a> Respir Physiol Neurobiol. 284, 103583(2021).</li>
<li>Cândido, L. D. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Different+tidal+volumes+may+jeopardize+pulmonary+redox+and+inflammatory+status+in+healthy+rats+undergoing+mechanical+ventilation%5BTitle%5D)+AND+%22Oxid+Med+Cell+Longev%22%5BJournal%5D)">Different tidal volumes may jeopardize pulmonary redox and inflammatory status in healthy rats undergoing mechanical ventilation.</a> Oxid Med Cell Longev. 2021, 5196896(2021).</li>
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</ol>

No conflicts of interest, financial or otherwise, are declared by the authors.

In this study, a structured APEC extubation approach was established for a rat model of MV, inspired by the first four failed extubations and the underlying causes. All 20 rats extubated using this approach succeeded and completed subsequent behavioral testing within the following three days. The approach, consisting of four key steps -- Approaching weaning, Preparing extubation, Executing extubation, and Post-extubation care -- was designed to ensure a smooth transition from mechanical to spontaneous breathing while min...

Mechanical ventilation (MV) remains a cornerstone of critical care, providing essential respiratory support for acute respiratory failure and serving as a vital adjunct during anesthesia for surgical procedures1. However, MV is associated with a range of complications, such as ventilator-induced lung injury2, ventilation-induced diaphragm and expiratory muscles dysfunction3,4,5,6, and ventilator-associated brain injury7,8. These complications contribute to extubation failure, prolonged stay in intensive care units (ICU) and hospitals, and increased mortality9. As ICU survival rates improve, attention has increasingly shifted toward the long-term consequences of MV, with post-ICU syndrome (PICS) emerging as a critical concern10. The pathophysiological mechanisms underlying PICS remain unclear, partly due to the lack of reliable animal models to capture the nuances of post-extubation recovery and long-term sequelae of MV11.
Rat models have been pivotal in advancing the understanding of MV-induced injuries, offering scalability, reproducibility, and mechanistic insights. However, most existing models focus on the acute effects of MV, with tracheostomy being the predominant method for MV in experimental settings12,13,14. While tracheostomy facilitates MV and weaning after it, it bypasses the upper airway, a critical anatomical and functional barrier. This increases the susceptibility to pulmonary complications such as ventilator-associated pneumonia15,16. Additionally, the absence of nasal airflow in tracheostomy models disrupts brain network synchronization. This complicates investigations into cognitive and neurological outcomes17,18. In contrast, endotracheal intubation /extubation models retain the integrity of the upper airway. They avoid the inherent disadvantages of tracheostomy and more closely resemble the clinical trajectory of weaning from MV.
However, existing extubation models often lack standardization, leading to considerable variability in the transition from MV to spontaneous breathing19,20. This lack of structure introduces risks of extubation-related complications, including airway obstruction, respiratory distress, and aspiration, which may result in animal mortality. Such failures not only compromise the ability to investigate long-term outcomes but also render the initial MV model ineffective, wasting valuable time, resources, and financial investment. These issues underscore the critical need for a structured extubation approach to ensure successful post-extubation survival and robust long-term studies.
To address these challenges, a structured extubation approach was developed for Sprague-Dawley (SD) rat models that closely aligns with clinical practices for weaning from MV. This approach encompasses four key stages: approaching weaning, preparing for extubation, executing extubation, and post-extubation care. Key procedural recommendations include maintaining light-to-moderate sedation during weaning, specifically, reducing propofol infusion to 50% of the dose used during full MV -- to allow spontaneous breathing while preventing agitation. Extubation readiness should be assessed based on a stable respiratory rate of 60-70 breaths per minute and adequate spontaneous tidal volumes, which can be approximated using a simple, calibrated homemade scale. Full recovery of consciousness is not required prior to extubation. Propofol infusion should be discontinued at the time of extubation to further reduce the risk of intubation-induced agitation. By standardizing the extubation process, this approach minimized variability, avoided extubation-related complications, and enhanced survival rates. This model has been optimized for MV durations of up to 6 h; extending MV beyond this period may necessitate modified sedation protocols, incremental weaning strategies, and careful physiological monitoring to ensure survival and reliable outcomes. Although validated in SD rats, the protocol can be adapted for other strains by adjusting ventilation settings to account for strain-specific respiratory mechanics and varying susceptibilities to lung injury. With appropriate modifications, the structured approach may also support longer-term ventilation studies, enhancing both reproducibility and translational relevance across experimental models.

<table><tbody><tr><td>16G Endotracheal Tube</td><td>NJKEWBIO</td><td>NA</td><td>Endotracheal tube</td></tr><tr><td>Blood Gas Analyzer</td><td>Epocal Inc</td><td>EPOC reader</td><td>Monitor blood gases</td></tr><tr><td>Intravenous Catheter</td><td>Introcan Safety</td><td>4254074B</td><td>Indwelled in the arteries and veins</td></tr><tr><td>Micro-syringe Pump</td><td>SLGO Medical Technology</td><td>CP-1000</td><td>Infusion of drugs</td></tr><tr><td>Pet Oxygen Concentrator</td><td>Beijing zhongshidichuang Science and technology development Co.,Ltd</td><td>ZS-MV</td><td>Supply of oxygen</td></tr><tr><td>Small Animal Heating Blanket</td><td>Beijing zhongshidichuang Science and technology development Co.,Ltd</td><td>ZS-T</td><td>Maintain temperature</td></tr><tr><td>Small Animal Ventilator</td><td>NJKEWBIO</td><td>KW-100</td><td>Provide breathing</td></tr></tbody></table>

a structured approach to extubation in mechanically ventilated rats

A Structured Approach to Extubation in Mechanically Ventilated Rats

Mechanical ventilation (MV) is widely used in critical care but is associated with various complications that affect both short- and long-term outcomes, including ventilator-induced lung injury, ventilator-induced diaphragm dysfunction, and ventilator-associated brain injury. These are key components of post-intensive care unit syndrome (PICS). Rodent models are vital for investigating the prolonged impacts and underlying mechanisms of MV, yet standardized post-extubation models remain limited. Extubation is a critical transition step that is often inconsistently performed in existing rat models, leading to failures and complications. This study presents a four-step structured extubation approach for Sprague-Dawley rat models of MV, designed to optimize the transition from MV to spontaneous breathing while minimizing extubation-related complications. The approach involved: (1) initiating weaning by reducing propofol sedation to 50% and assessing readiness via respiratory rate, chest displacement, arterial blood gases, and reflexes; (2) preparing for extubation through airway clearance and maintenance of oxygenation; (3) executing extubation with maintained sedation and controlled tube removal; and (4) providing post-extubation care involving continuous monitoring and oxygen support. Validated through 20 successful extubations following initial failures, this model offers a valuable platform for studying the long-term effects of MV, particularly in the context of PICS. This approach is optimized for 6 h of MV and is assumed to be extendable to other strains and longer ventilation durations, although such adaptations require careful validation and monitoring to ensure reliability and animal welfare.

This structured extubation approach was developed on four failed extubations and 20 subsequent successful extubations. In the first four attempts, extubation was performed based on the experience or individual judgment. Reasons for the four rats' failed extubation included agitation during extubation(n = 2), post-extubation respiratory insufficiency (n = 1), and airway obstruction by secretions (n = 1). These failures highlighted that optimal sedation, a clear airway, and sufficient oxyge...

This study proposes a structured extubation approach tailored to rat models of mechanical ventilation (MV). The approach facilitates a smooth transition from MV to spontaneous breathing while minimizing extubation-related complications. Standardization of weaning, airway management, and post-extubation care enhances the reliability and reproducibility of experimental studies.

Mechanical ventilation (MV) is widely used in critical care but is associated with various complications that affect both short- and long-term outcomes, ...

Mechanical ventilation is lifesaving, but it can cause brain and die from injury. We aim to develop a extubation model in rats. This model simulates clinical weaning to study this injury better.Currently, most mechanical ventilation models only look at short-term effects and mainly use a tracheostomy, which limit clinical relevance. Tracheostomy makes the ventilation earlier, but bypasses the upper airway, raising the risk of lung infection and disrupting brain signaling. This make it hard to study injury and recovery accurately.We're filling the gap in rat models by creating a clear, step-by-step extubation protocol. It follows clinical practice, lowers complications, and helps rats recover more safely after ventilation. Using this extubation model, we aim to investigate the molecular mechanisms underlying ventilator-induced injuries to the brain and the diaphragm as well as the biological pathways involved in their potential recovery.To begin, prepare the ventilator and adjust the oxygen concentration. Get the intubation device ready, and position the anesthetized rat for intubation. Using forceps, gently pull the rat's tongue toward the right oral corner.Insert the intubation device at the base of the tongue and advance it toward the epiglottis. Then lift the device tip to expose the glottis, and insert the endotracheal tube into the trachea during inhalation. Once the tube is in place, connect the rat to the ventilator.Now set the ventilator parameters based on the rat's weight and experimental requirements. Infuse propofol continuously using a syringe pump to maintain anesthesia. Monitor the rat's blood gas levels throughout the procedure to ensure respiratory stability.For weaning, reduce the propofol infusion rate by 50%using the syringe pump settings, and waiting for approximately 10 minutes for the sedation level to decrease. Disconnect the rat from the ventilator for one to two minutes to assess readiness for weaning. During this period, ensure the respiratory rate is between 60 to 70 breaths per minute, confirm a chest displacement of at least one millimeter, and verify that arterial blood gas values and pH levels are within acceptable ranges.If all parameters are met, disconnect the ventilator. To prepare the rat for extubation, use a custom-made face mask to ensure adequate oxygenation. Then observe the rat's skin color to assess oxygenation.Using a self-made suction device, perform suctioning at a rate of approximately two milliliters per second for three to four seconds per session to clear airway secretions. Next, using a two-handed technique, stabilize the rat's head with the left index finger and thumb. Then gently remove the endotracheal tube with the right index finger and thumb.Discontinue the propofol infusion once the tube is removed. Monitor the rat's vital signs post-extubation, and continue providing oxygenation as needed using the custom face mask. In the structured protocol applied to 20 rats, all extubations were successful, with full recovery achieved in approximately 48.5 minutes post-extubation.During the approaching weaning step, average oxygen partial pressure was 87.6 millimeters of mercury, carbon dioxide partial pressure was 43.2 millimeters of mercury, and pH was 7.421. No complications were reported during either the extubation phase or the post-extubation care period.

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Research

JoVE Journal

Medicine

Rodent thymectomy is a valuable technique in immunological research.  Here, a protocol for complete thymectomy in adult rats using a mini-sternotomy along with non-invasive intubation and positive pressure ventilation to minimize perioperative morbidity and mortality is described.

Complete Thymectomy in Adult Rats with Non-invasive Endotracheal Intubation

Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. Here, we describe the development of a rat EVLP program and refinements that allow for a reproducible model for future expansion.

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

Here we describe a detailed protocol for invasive measurements of hemodynamic parameters including portal pressure, splanchnic blood flow, and systemic hemodynamics in order to characterize the portal hypertensive syndrome in rats.

Invasive Hemodynamic Characterization of the Portal-hypertensive Syndrome in Cirrhotic Rats

The rodent left pneumonectomy is a valuable technique in pulmonary hypertension research. Here, we present a protocol to describe the rat pneumonectomy procedure and postoperative care to ensure minimal morbidity and mortality.

The Left Pneumonectomy Combined with Monocrotaline or Sugen as a Model of Pulmonary Hypertension in Rats

A rodent model of left heart volume overload from mitral regurgitation is reported. Mitral regurgitation of controlled severity is induced by advancing a needle of defined dimensions into the anterior leaflet of the mitral valve, in a beating heart, with ultrasound...

An Image Guided Transapical Mitral Valve Leaflet Puncture Model of Controlled Volume Overload from Mitral Regurgitation in the Rat

Here, we present a reproducible intensive care unit-oriented endotoxin model in rats.

A Reproducible Intensive Care Unit-Oriented Endotoxin Model in Rats

A mouse surgical model to create left lung ischemia reperfusion (IR) injury while maintaining ventilation and avoiding hypoxia.

A Mouse Model of Orotracheal Intubation and Ventilated Lung Ischemia Reperfusion Surgery

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

Right heart failure (RHF) is characterized by right-sided cardiac dilation and hypertrophy, leading to ventricular and atrial malfunction. Cardiopulmonary conditions associated with RHF are accompanied by an increased risk for cardiac arrhythmias. This article describes a standardized model of pulmonary artery banding-induced RHF associated with enhanced ventricular and atrial arrhythmogenesis.

Rat Model of Right-Sided Cardiac Remodeling and Arrhythmia Using Pulmonary Artery Banding

Here, we present a method for assessing the activation and block of sensory axons in peripheral nerves in acute, anesthetized, in vivo rat experiments using two types of spinal electrophysiological measurements that can discriminate the activity of nerve fiber subtypes: Local Field Potentials and Wide Dynamic Range single neuron recordings.

Electrophysiological Methods to Assess Peripheral Pain Block in an Anesthetized Rat

This protocol describes a simple, low-cost, video-assisted method for orotracheal intubation, enabling rapid and visually guided intubation in adult rats under isoflurane anesthesia.

Video-Assisted Orotracheal Intubation in Rats Using a Low-Cost Smartphone-Connected Otoscope

Learn a structured extubation protocol in mechanically ventilated rats to simulate clinical weaning and reduce complications. This method improves the reliability of studying ventilator-induced brain and diaphragm injuries.

A Structured Approach to Extubation in Mechanically Ventilated Rats

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