Endotracheal suctioning (ETS) is a conventional nursing intervention used to decrease pulmonary complications in the critically ill patient. ETS provides a particular dilemma for the head-injured patient because it increases intracranial pressure and may put the patient at increased risk for intracranial hypertension and cerebral ischemia. Research in endotracheal suctioning targets understanding the ETS response in the severely head-injured patient. This article reviews the major research focused on suctioning the head-injured patient. The guidelines for practice based on this research include preoxygenating patients prior to suctioning, limiting suction duration to 10 seconds, limiting suction passes to 1-2 per procedure, using hyperventilation with caution, not rotating the head, keeping negative suction pressure under 120 mm Hg, and not using suction catheters with outer to inner diameter ratios greater than .50.