Table II.

Supplemental oxygen (low-flow versus high-flow systems).

Device	Flow	Estimated maximal FiO2	Advantages	Disadvantages
Low-flow systems
Flow-by oxygen	6 to 8 L/min	25 to 45%	Minimal equipment, Easy patient accessibility for treatments	Oxygen dilution with room air, patient intolerance, personnel required to hold tube
Oxygen face mask	1 to 6 L/min	35 to 45%	Minimal equipment, easy patient accessibility for treatments	Patient intolerance, risk of CO2 rebreathing, personnel required to hold mask
Oxygen cage	N/A	50 to 60%	Low stress to patient, suitable for small dogs and cats	Difficult to monitor patient, oxygen dilution with room air every time cage door opened, development of hyperthermia due to heat and humidity in cage, cost of commercial cages
Nasal cannulas	Flow not to exceed a total of 5 L/min through each nasal cannula	30 to 60% (depending on flow rate)	Easy patient access for evaluations and treatment, can effectively achieve high oxygen concentrations	Nasal irritation, sneezing, nasal drying, panting leading to air entrainment
High-flow system
High-flow oxygen therapy	Up to 60 L/min	21 to 100% space, PEEP effects,	Washout of anatomic dead patient mobility, nasal mucosal humidification and warming of inspired air	Noise of machine, reduced irritation, can delay initiation of mechanical ventilation

FiO₂ — Inspired oxygen content; L/min — Liters per minute; N/A — Not applicable; CO₂ — Carbon dioxide; PEEP — Positive end expiratory pressure.