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

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.