Nasal oxygen catheter are fairly straightforward to place and you can use unilateral or bilateral. But placement itself can be very stressful in some patients. Depending on the flow rates used relative to the size of the patient you may get inspired oxygen concentrations of 30-60%. I usually work out their expected minute volume to get an idea of what the highest rate I would use is. Tidal volume is ~10ml/kg and let’s say they are breathing at 40 breaths per minute. That gives a minute volume of 400 ml/kg so a 20 kg dog would get 8 litres a minute. If I don’t think that I need the full whack then I usually put them on about 100 ml/kg/min.I think that nasal tubing of any kind is potentially dangerous in head trauma patients because of the risk of sneezing, coughing or retching resulting in increases in intracranial pressure so I usually use an alternative administration method in these fellas.This pictures here are mainly to show you the two different ways of attaching them to the patient. In the fella on the left it is actually a nasogastric tube.