Which suction catheter size is most appropriate for a patient with a size 7.5 mm ID ETT?

The most appropriate suction catheter size for a patient with a size 7.5 mm internal diameter (ID) endotracheal tube (ETT) is indeed the 10 French (Fr) catheter. The selection of suction catheter size is primarily determined by the internal diameter of the ETT, as it is crucial to choose a catheter that will effectively clear secretions without causing trauma or increasing airway resistance significantly.

In general, the rule of thumb for determining the size of the suction catheter is to select a diameter that is no more than half or two-thirds of the ID of the ETT. For a 7.5 mm ID ETT, the equivalent diameter in French is approximately 22 Fr (with 1 mm equating to about 3 Fr). Therefore, a 10 Fr suction catheter, which is about 3.3 mm in diameter, falls well within the acceptable range for use with a 7.5 mm ID ETT, allowing for effective suctioning while minimizing the risk of airway complications.

Larger catheter sizes, such as 12 Fr and 14 Fr, may be too bulky and could potentially obstruct airflow, cause trauma to the airway, or create unnecessary resistance that hampers ventilation. The 8 Fr