Comparison of intranasal and intratracheal oxygen administration in healthy awake dogs.

Intranasal (IN) and intratracheal (IT) oxygen administration techniques were compared by measuring inspired oxygen concentrations (FIO2) and partial pressures of arterial oxygen (PaO2) in 5 healthy dogs at various IN (50, 100, 150, and 200 ml/kg of body weight/min) and IT (10, 25, 50, 100, 150, 200, and 250 ml/kg/min) oxygen flow rates. Intratracheal administration of oxygen permitted lower oxygen flow rates than IN administration. Each IT oxygen flow rate produced significantly higher FIO2 and PaO2 than the corresponding IN flow rate. An IT oxygen flow rate of 25 ml/kg/min produced FIO2 and PaO2 values equivalent to those produced by an IN oxygen flow rate of 50 ml/kg/min. An IT oxygen flow rate of 50 ml/kg/min produced FIO2 and PaO2 values equivalent to those produced by IN oxygen flow rates of 100 and 150 ml/kg/min. All IT oxygen flow rates greater than or equal to 100 ml/kg/min produced FIO2 and PaO2 values that were greater than FIO2 and PaO2 values produced by IN oxygen flow rates of 200 ml/kg/min. The lowest flow rates studied (50 ml/kg/min, IN, and 10 ml/kg/min, IT) produced PaO2 capable of maintaining 97% hemoglobin saturation, which should be adequate for most clinical situations. Arterial blood gas analysis and FIO2 measurements are necessary to accurately guide oxygen flow adjustments to achieve the desired PaO2 and to prevent oxygen toxicity produced by excessive FIO2.