Check coagulation status and obtain consent for non-urgent tubes. Patients should be started on nasal oxygen and placed on continuous pulse oximetry monitoring. Place the patient in a supine or semi-recumbent position with their ipsilateral arm behind their head. Ideally, the head of the bed should be elevated 30 to 60o. This lowers the diaphragm and decreases the risk of injury to the diaphragm, spleen, or liver.

The ideal insertion site is approximated by the fourth to fifth intercostal space in the anterior axillary line at the horizontal level of the nipple. This area is within the "triangle of safety" (pictured below), outlined medially by the lateral border of the pectoralis major anteriorly, laterally by the mid-axillary line and the 4th to 5th intercostal space inferiorly. The apex of the triangle is located just below the axilla. Note: the nipple line may be an unreliable landmark for the interior border of the triangle in women due to the presence of breast tissue. Always avoid the breast tissue, even in prepubescent girls.

Landmark this site by first locating the patient's clavicle. Move your fingers downwards counting the ribs as you go. Once you have located the 4th to 5th intercostal space, move laterally to the anterior axillary line. The INCISION will be made here. The chest tube will actually be inserted one interspace above this point. Mark the incision site.