Oxygen reduces tourniquet-associated pain: a double-blind, randomized, controlled trial for application in hand surgery.

Background: Why do limb tourniquets cause pain? If ischemia is the mechanism, can supplemental oxygen reduce pain? The Reducing Tourniquet Associated Pain study investigated whether this simple treatment could extend tourniquet tolerance time to facilitate hand surgery under local or regional anesthesia.

Methods: The Reducing Tourniquet Associated Pain study was a double-blind, randomized, controlled trial of healthy volunteers. Participants received either 50% inhaled oxygen or air placebo via a face mask for 3 minutes before and up to 30 minutes after upper arm tourniquet inflation to 250 mmHg.

Spontaneous surgical emphysema of the larynx following hyperextension of the neck.

Surgical emphysema of the larynx is rare in the absence of trauma and there are a paucity of case reports that describe such conditions. We present what we believe to be an unusual, atraumatic mechanism for mucosal breech of the larynx with subsequent surgical emphysema. Nasendoscopy revealed oedema of the arytenoid cartilage and computed tomography revealed moderate subcutaneous emphysema of the larynx.

Multi-cellular rosettes in the mouse visceral endoderm facilitate the ordered migration of anterior visceral endoderm cells.

The visceral endoderm (VE) is a simple epithelium that forms the outer layer of the egg-cylinder stage mouse embryo. The anterior visceral endoderm (AVE), a specialised subset of VE cells, is responsible for specifying anterior pattern. AVE cells show a stereotypic migratory behaviour within the VE, which is responsible for correctly orientating the anterior-posterior axis.