How can a rat be given oxygen? - briefly
Oxygen can be delivered to a laboratory rat using a miniature nasal cannula connected to a flow‑meter or by housing the animal in a sealed chamber with a regulated oxygen concentration. Continuous monitoring of respiration and body temperature ensures physiological stability.
How can a rat be given oxygen? - in detail
Supplying oxygen to a laboratory rat requires a controlled delivery system, continuous monitoring, and appropriate equipment to maintain physiological stability.
A mask fitted to the animal’s snout is the simplest method. The mask connects to a precision flow regulator that delivers a known concentration of oxygen, typically 100 % or a mixed gas blend. The regulator must be calibrated before each use. The mask should be secured with a lightweight strap to prevent displacement while allowing free movement of the jaw for breathing.
For procedures requiring higher precision, endotracheal intubation is employed. A sterile, appropriately sized tube (0.8–1.0 mm internal diameter) is inserted through the glottis under a dissecting microscope. The tube is connected to an anesthesia ventilator or a manual resuscitation bag equipped with an oxygen inlet and a pressure‑controlled valve. Ventilator settings—tidal volume, respiratory rate, and inspiratory/expiratory ratio—are adjusted to the rat’s weight (approximately 0.2 L/kg tidal volume). Capnography and pulse oximetry provide real‑time feedback on ventilation adequacy and arterial oxygen saturation.
When prolonged exposure is needed, an oxygen‑enriched chamber offers a hands‑free solution. The chamber is sealed, fitted with an inlet port that supplies a constant flow of oxygen (e.g., 2 L/min for a 10‑L chamber). An exhaust valve maintains slight positive pressure to prevent ambient air ingress. Temperature and humidity controls prevent hypothermia and drying of mucous membranes. Continuous observation through a transparent wall ensures the animal remains alert and exhibits normal breathing patterns.
Key monitoring parameters include:
- Fraction of inspired oxygen (FiO₂) measured with a calibrated gas analyzer.
- Respiratory rate and tidal volume recorded via a pneumotachograph.
- Arterial oxygen saturation (SpO₂) obtained with a clip‑type pulse oximeter.
- Core temperature monitored with a rectal probe; maintain 37 ± 0.5 °C.
Safety considerations:
- Verify all connections for leaks before initiating flow.
- Use humidified oxygen to reduce airway irritation.
- Limit exposure duration to avoid hyperoxia‑induced oxidative stress; return to ambient air after the procedure unless continuous support is medically justified.
- Follow institutional animal care guidelines for anesthesia and post‑procedure recovery.
By selecting the appropriate delivery method, calibrating equipment, and adhering to stringent monitoring protocols, researchers can reliably provide oxygen to a rat throughout experimental or clinical interventions.