The Pet Oxygen Mask is the most practical option for at- home use. It is available in three different sizes to accommodate the patient’s snout and is exceptionally easy for pet parents to use. The rubber diaphragm is usually removed to increase patient acceptance, decrease breathing resistance and prevent rebreathing unless the size of the patient and gas flow justify their use. Veterinary hospitals can employ alternative oxygen administration devices depending on the pet parent, patient and condition, and the possible use scenarios, such as during transfer or at-home use.
In addition to masks, oxygen adminstration E-collars are commercially available or can be created by using plastic cling wrap covering 80% of the ventral opening1 with the tube entering at the collar. The recommended flow rates to achieve desired oxygen supplementation and avoid rebreathing are 200ml/kg/min for a mask and 100ml/kg/min for a vented e-collar2 The actual FiO2 obtained is dependent on:
1) The minute volume (how much air the patient is moving in and out of their lungs per minute)
2) The space of the device and other dead space
3) Venting and entrainment from the device
4) The oxygen flow rate.3
One of the most efficient methods for administering oxygen to veterinary patients is the nasal (pharyngeal) catheter which provides an FiO2 of approximately 30% at 50 ml/kg/min via single catheter ranging to 60% at 100ml/kg/min with via double catheter3, 4 Due to their length, catheters provide a higher FiO2 at a lower flow rate and are better tolerated than human nasal cannulas. Nasal (pharyngeal) catheterization is an easy and cost-effective procedure:
1) Premeasure a red rubber or commercially available specific catheter so that it occupies 1/3 to ½ of the diameter of the nostril and spans from the nostril opening to the to the lateral canthus of the eye.
2) Instill proparacaine into the nostril; the nose is pushed dorsal while the catheter is aimed ventrally to assure placement into the ventral (largest) meatus. Passage is accommodated with the use of lidocaine jelly or water based lubricant.
3) Once the catheter is advanced to the pre-measured length (stop if resistance is encountered and reattempt), place a tape or other butterfly on the catheter just caudal and slightly ventral to the nostril and suture or staple it to the muzzle.
4) Secure the catheter on the side of the face/head or up the middle of the face and on top of the head.
Nasal (pharyngeal) catheterization is recommended for transporting medium to large dogs.
Any time oxygen is administered in a way that encloses the mouth (mask), head (e-collar) , or patient (oxygen cage), overheating and additional anxiety to the patient must be avoided. If a mask is not feasible, other administration options can be considered. Most pet parents report their pets calm down after the mask is applied and kept in place for a minute or so as the hypoxemia is addressed.
About Sean Smarick, VMD, DACVECC
1. Crowe, D. (2009), Delivering Supplemental Oxygen to Dogs and Cats: a Practical Review. DVM 360.
2. Burkitt Creedon, J., Davis H. (2012), Advanced Monitoring and Procedures for Small Animal Emergency and Critical Care. Wiley-Blackwell.
3. Zimmerman, M. E., Hodgson, D. S., & Bello, N. M. (2013). Effects of oxygen insufflation rate, respiratory rate, and tidal volume on fraction of inspired oxygen in cadaveric canine heads attached to a lung model. American journal of veterinary research, 74(9), 1247–1251.
4. Dunphy ED, Mann FA, Dodam JR, Branson KR, Wagner-Mann CC, Johnson, PA, Brady MA. (2002), Comparison of unilateral versus bilateral nasal catheters for oxygen administration in dogs. J Vet Emerg Crit Care, 12:245–251.