Placed similarly to the nasal catheter except the tip of the catheter is at the medial canthus of the eye or even further.
It is important that the tip not be caudal to the leading edge of the soft palate.
Because oxygen flow is right at the pharyngeal vault region, a small amount of CPAP (continuous positive pressure ventilation)
may be induced in a patient that closes its mouth or breathes with a certian amount of "grunt". This increases functional
residual capacity in the lungs. It is indicated for acute treatment of any cause of severe pulmonary edema, such as that related
to congestive heart failure, centroneurogenic, trauma and electrocution. Provide oxygen at 50-100 ml/kg/min. These can be
placed in both nostrils.
Photo 5: Oxygen analyzer used to determine oxygen percentage inside a Crowe Collar being used on a cat with breathing difficulty.
This is placed for oxygen delivery in patients with partial laryngeal paralysis or tracheal collapse but for whom placing
a tube is risky, such as in head-injured patients. Placement is similar to nasal oxygen except the head is fully extended
as the catheter is advanced past the level pharynx and into the trachea.
The larynx first is "sedated" with proparicaine by tipping the nose high at 90 degrees from horizontal and then multiple drops
of proparicane given (three to six).
The nasal tube is then inserted rapidly into the pharynx as the patient takes a breath. Placement is confirmed by aspirating
air easily from the tube. Coughing may or may not occur. Radiographs may be needed to confirm. Provide oxygen at 50 ml/kg/min.
Photo 6: Results of a research study comparing oxygen concentrations reached over time with various methods of oxygen delivery.
This is used if the nose has been injured, is bleeding or contains exudate, or if the animal has suffered a head injury and
all the nasal–type catheters are contraindicated.
There are various ways that these can be placed. One is to place a small amount of buffered lidocaine on the midline of the
ventral neck and, after a small nick is made in the skin as a relief incision, an appropriate length 14-18 g IV catheter is
attached to a syringe.
It is guided through the skin nick and between two tracheal rings. Air is aspirated, indicating the catheter tip is in the
tracheal lumen. The entire system is advanced slightly further inward and down the lumen and air aspirated again to insure
the catheter is in the lumen.
The catheter is advanced off the needle and the needle removed.
Percent of oxygen achieved and time taken to reach noted levels
A T-port is attached to the tracheal catheter, and a light bandage is applied. An IV administration set can be attached and
used to flow oxygen. A flow rate of 25-50 ml/kg usually is enough to raise concentrations above 60 percent.