How I Supplement Oxygen

Oxygen supplementation must be provided in the least stressful way. Fighting with a patient to provide mask oxygen will prove worthless as the increase in oxygen demand by the muscles will offset the increase in inspired oxygen. There is a wide variety of options available to provide patients with oxygen ranging from extremely simple, for example flow by, to the extremely labour intensive, i.e. ventilation.

Methods that can be considered include:

“Flow by” or mask oxygen
This is suitable for short term supplementation during assessment and most animals will tolerate flow by oxygen.

Oxygen tents, chambers and cages
Increasing complexity is seen in these. Some can be extremely expensive but allow accurate control of oxygen concentration and temperature. They also provide a quiet, secure environment and are invaluable when dealing with dyspnoeic cats.

Nasal prongs and catheters
These are most useful in dogs and are easy to place and maintain. They are less useful in panting patients.

Ventilation
This is the only way to provide 100% inspired oxygen concentration but is extremely labour intensive and may not be associated with a good prognosis, Anaesthesia is a requirement in the early stages.

The response to oxygen therapy should be monitored as with any therapeutic intervention. Although a number of respiratory diseases are oxygen responsive there are some that are not, e.g. pleural effusion and intrapulmonary shunting. The patient should be assessed and monitored carefully once supplementation has started to ensure the treatment is having the desired effect. Arterial blood gas analysis is the best way to monitor oxygen therapy. Pulse oximetry may be useful in some patients and the majority of patients will show improvement of their clinical signs with correction of hypoxaemia, i.e. normalisation of heart rate, respiratory rate and mucous membrane colour. It should be remembered that cyanosis is an extremely late indicator of hypoxaemia and associated with life threatening desaturation.
Oxygen supplementation is beneficial in the majority of critically ill and emergency patients and can be life saving in dyspnoeic patients. The best method to supplement oxygen is the one associated with the least stress for the patient. Ideally oxygen cages provide this, however they are expensive to purchase and maintain. Nasal prongs and cannulae provide an effective and easy alternative in the majority of patients.