Endotracheal Intubation via Tracheotomy and Subsequent Thoracotomy in Rats for Non-Survival Applications
March 15th, 2024
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.
The scope of our research is the spectral characterization of physiological and diseased organs and tissues in patients, as well as animal models. Using hyperspectral imaging, we hope to be able to reliably evaluate tissue, establish this technology as a new diagnostic pillar in medicine and close existing diagnostic gaps. Current experimental challenges for the spectral characterization of thoracic organs were the necessity for exposed organ surfaces and the movement artifacts during coating process due to mechanical ventilation, both could be successfully addressed with this new technique.
We will further focus on the spectral characterization of organs and on the transfer of spectral data between different species. This will allow us to abstract insights obtained from animal models and apply them to humans for patient benefit. To begin, fold the cannulas at a 135 degree angle, one centimeter from the tip.
Using a luer lock, connect the cannulas to plastic perfusion tubes. Then, place a heating pad on the steel plate of the surgical exposure apparatus for thermal support. Prepare the surgical preparation hooks with attached plastic tubes and surgical mosquito clamps to later apply tension to the tissue for surgical exposure.
Next, shorten and bevel intravenous catheters of different sizes. Insert a guide wire from an arterial leadercath set into the catheter most suited for the animal size for the Seldinger technique during intubation. After anesthetizing the rat, perform a toe pinch to check the depth of anesthesia.
Then, apply ophthalmic ointment to the animal's eyes. Administer additional analgesia before the thoracotomy with a subcutaneous injection of carprofen. Use a transnasal neonatal mask to offer 100%oxygen inhalation to the animal to saturate its circulation with oxygen.
After five minutes, replace the neonatal mask with a neonatal ventilation bag constructed with a male plastic syringe luer lock tip. Provide oxygen and overflow with the syringe tip positioned close to the animal's nasal tip. Then, make a median thoraco cervical skin incision of the required length and use surgical preparation hooks to expose the surgical site.
Next, using fine scissors, perform blunt dissection through the cervical fascia. Expose the sternocleidomastoid and infrahyoidal muscle. After dissecting the left lateral membrane, lateralize the median infrahyoidal muscle to the right.
Employ overholt clamps to perform blunt dissection towards the trachea and tunnel the trachea. Then, with the silicone vessel loop, sling the trachea and secure the distal trachea with a double sling using a polyfilament suture for later endotracheal cannula fixation. Using atraumatic pliers, extend the trachea caudally.
Then using scissors, make a partial incision of the trachea 180 degrees in circumference. Now, insert a Seldinger guide wire with a flexible end into the trachea and guide the appropriately sized modified intravenous catheter into the trachea. Then, remove the Seldinger wire and connect the luer lock tip of the tracheal catheter to the modified ventilation bag.
After that, start manual lung protective ventilation with high frequency and low tidal volume. Secure the previously placed locking suture with a sliding knot to prevent air leakage and accidental catheter removal. Next, using blunt and stable material scissors, start the median thoracotomy from the xiphoid and continue cranially through the sternum.
Pause ventilation briefly when advancing the scissors substernally, and when cutting to avoid lung trauma. Remove the surgical preparation hooks from the skin and insert them into the thorax to gain further exposure. Utilize surgical preparation hooks to gain thoracic exposure and remove mediastinal serosal membranes.
The oxygen saturation never fell below 92%and all rats survived the 20 minutes required for the experimental measurements.
Overview
This study presents a standardized procedure for endotracheal intubation via tracheotomy followed by thoracotomy in rats. The method aims to enhance the precision and reproducibility of non-survival applications requiring invasive ventilation and exposure of thoracic organs in in vivo rat models.
Key Study Components
Area of Science
- Neuroscience
- Invasive Ventilation Techniques
- Animal Model Research
Background
- Hyperspectral imaging is being explored for the spectral characterization of physiological and diseased organs.
- Current challenges include the need for exposed organ surfaces and movement artifacts during mechanical ventilation.
- This study addresses these challenges with a new technique.
- The research aims to transfer insights from animal models to human applications.
Purpose of Study
- To develop a reliable method for endotracheal intubation and thoracotomy in rats.
- To improve the evaluation of thoracic organs using hyperspectral imaging.
- To establish a new diagnostic approach in medicine.
Methods Used
- Preparation of surgical instruments and anesthesia for rats.
- Application of a neonatal mask for oxygen saturation.
- Execution of a median thoraco cervical skin incision and blunt dissection.
- Insertion of a tracheal catheter and initiation of manual lung protective ventilation.
Main Results
- All rats maintained oxygen saturation above 92% during the procedure.
- Successful endotracheal intubation and thoracotomy were achieved.
- The method demonstrated reproducibility and precision for experimental measurements.
- All subjects survived the 20-minute experimental duration.
Conclusions
- The standardized procedure enhances the reliability of invasive ventilation in rat models.
- This technique may facilitate better translational research from animal models to human applications.
- Future studies can build on this method for further advancements in diagnostic imaging.
Frequently Asked Questions
Executive Industry Relevance
Reliable endotracheal intubation via tracheotomy in rat models addresses critical challenges in translational research requiring controlled ventilation and thoracic access. This protocol enables consistent oxygenation and exposure of thoracic organs, supporting high-fidelity physiological measurements and minimizing procedural variability. The approach strengthens predictive confidence for preclinical studies involving respiratory or thoracic interventions.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables precise physiological manipulation for mechanistic studies of thoracic organ function.
- Reduces technical failure rates, supporting robust target validation in respiratory research.
- Facilitates reproducible experimental conditions for hypothesis-driven investigations.
Screening & Assay Development
- Provides a standardized model for evaluating interventions requiring invasive ventilation.
- Supports quantitative assessment of organ responses under controlled ventilation parameters.
- Improves assay reproducibility by minimizing oxygenation variability and procedural complications.
Translational & Preclinical Research
- Enables spectral characterization of thoracic organs, aligning preclinical data with translational biomarker development.
- Supports transferability of physiological insights from animal models to human applications.
- Reduces animal loss and suffering, enhancing ethical standards in preclinical research.
Pipeline & Workflow Integration
This protocol integrates into the discovery-to-preclinical continuum for respiratory and thoracic research, enabling reliable data generation for lead identification and mechanistic de-risking.
- Discovery Biology: Supports hypothesis testing by ensuring consistent organ exposure and oxygenation.
- Screening: Delivers reproducible ventilation and thoracic access for compound or device evaluation.
- Analytics: Enables quantitative measurement of physiological and spectral parameters in thoracic tissues.
- Translational Research: Facilitates alignment of animal model data with human diagnostic needs.
- Enterprise Reuse: Establishes a reusable protocol for diverse non-survival thoracic interventions in rats.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in thoracic and respiratory studies.
- Operational Value: Standardizes intubation and ventilation procedures, improving reproducibility and scalability.
- Strategic Value: Enables better go/no-go decisions by minimizing technical confounders in preclinical models.
- Portfolio Impact: Supports risk-adjusted prioritization of respiratory and thoracic research programs.
Implementation Considerations
- Requires surgical expertise in tracheotomy and thoracotomy techniques.
- Needs appropriate anesthesia, ventilation equipment, and monitoring infrastructure.
- Demands cross-team standardization for reproducible outcomes across studies.
- Adaptation may be needed for different rat sizes or experimental endpoints.
- Limited to non-survival applications due to the invasive nature of the procedure.
