Use of an Integrated Low-Flow Anesthetic Vaporizer, Ventilator, and Physiological Monitoring System for Rodents

This protocol highlights best uses for an all-inclusive anesthesia and physiological monitoring suite that includes a Low-Flow Electronic Vaporizer, an integrated ventilator, a pulse oximeter and a Far Infrared Warming Pad. This methodology is useful for any facility with limited bench or lab space. An all-in-one system also eliminates the need for compressed gas tanks and separate physiological monitoring equipment.

Demonstrating the procedure will be Luke Schepers, a Biomedical Engineering PhD student at Purdue University. To set up the Low-Flow Vaporizer, select a carrier gas source, and remove the red cap from the inlet port on the back of the system to allow the system to take in room air. If using a compressed gas source, use a pressure regulator and pressure reducer set to 15 pounds per square inch.

And connect the device to the compressor gas port on the back of the system. Connect the charcoal canister to the exhaust port. And connect the accessory connector to the inspiratory and expiratory ports on the front of the system.

Connect the induction chamber to the branches with blue clips, and the nose cone to the branches with white clips. To set up the integrated ventilator, connect the intubation connector tubing to the branches with the yellow clips. To calibrate the ventilator dead space on the Vent Run Screen, touch Setup and Calibration and Tests then select Measure dead space and press Dial B.To set up the integrated pulse oximeter, connect the sensor of the mouse stat port on the back of the system.

To set up the Far Infrared Warming Pad, connect the warming pad to the pad power port on the front of the system. Then connect one sensor to the body sensor port and the other to the pad sensor port and secure the pad sensor to the warming pad. To configure the system settings for anesthesia delivery in the Anest Run Screen, touch Setup and select the anesthetic agent.

Touch, Type anest and turn Dial B to select isoflurane or sevoflurane. To set this syringe size, touch Syringe size and turn Dial B to select a size. Touch Back to return to the Anest Run Screen and use the bottle top adapter to fill the syringe with anesthetic.

Connect the syringe to the anesthesia system and touch Remove to move the pusher block backwards as necessary. To prime the syringe, press and hold prime to move the pusher block forward until the block just touches the top of the syringe plunger. To set up the mechanical ventilation, open the Vent Run Screen tab and press Setup.

Press Body weight, and enter the weight of the animal. Then press Priority to select volume or pressure controlled ventilation. The appropriate respiratory rate and tidal volumes will be automatically set.

To set the pulse oximetry parameters, open the Oxy run screen tab and press Setup. press Minimum HR and turn Dial B to set the minimum allowed heart rate reading. To set the warming parameters in the warm run screen, press Setup and select a warming method and a target temperature setting.

To anesthetize the mouse from the Anest Run Screen, touch Induction to begin the airflow. The default induction flow rate is 500 milliliters per minute. Turn Dial A to adjust the flow rate as necessary.

Place the mouse in the induction chamber and close the lid tightly. Adjust the anesthetic agent concentration dial to 3%for isoflurane. The default induction flow rate is 500 milliliters per minute.

Turn Dial A to adjust the flow rate as necessary. Press Deliver to begin anesthetic delivery. Once the animal is sufficiently anesthetized, touch Induction again, then Flush chamber to reduce residual anesthetic gas in the chamber.

Open the clips leading to the nose cone and close the clips leading to the chamber. Touch Nose cone to begin the airflow and immediately fit the nose cone onto the animal. Center the animal on the Infrared Warming Pad then insert the animal sensor as a rectal probe to control the body temperature.

To initiate the mechanical ventilation, place the anesthetized animal on the intubation stage and use a thread fixed to the vertical intubation stage to suspend the animal from its upper incisors. Gently displays the animal's tongue to the side and use the lights provided in the innovation kit to visualize the trachea. Carefully insert the endotracheal tube.

Correct placement can be verified by connecting a small air bladder to the tube and checking for lung inflation. Touch Stop nose cone to stop the airflow, close the clips to the nose cone and open the clips to the ventilation tubing. Connect the endotracheal tube to the ventilation tubing and touch Start ventilator to begin the ventilation.

To begin the physiological monitoring, lightly clip the sensor onto one hind paw of the animal, the pulse oximeter will automatically begin reading the heart rate and the blood oxygen saturation. Touch the Oxy run screen tab to view the pulse oximetry data. The heart rate and the blood oxygen saturation can be monitored during maintenance via pulse out symmetry.

In this representative analysis, the animal's heart rates and blood oxygen saturation remained stable with few significant changes observed in either measurement for all of the groups. And with the blood oxygen saturation remaining between 82 to 99%This technique allows researchers to deliver anesthesia with lower flow rates and without the need for compressed gas. Lower flow rates lead to less gas waste and less exposure for research personnel.