Time to oxygenation for cannula- and scalpel-based techniques for emergency front-of-neck access: a wet lab simulation using an ovine model.

Emergency front-of-neck access to achieve a percutaneous airway can be a life-saving intervention, but there is debate about the preferred technique. This prospective, observational study was designed to compare the two most common emergency surgical airway techniques in a wet lab simulation using an ovine model. Forty-three doctors participated. After providing standardised reading, a lecture and dry lab benchtop training, participants progressed to a high-fidelity wet lab simulation. Participants entered an operating theatre where a 'cannot intubate, cannot oxygenate' situation had been declared and were directed to perform emergency front-of-neck access: first with a cannula technique (14-gauge cannula insertion with ventilation using a Rapid-O2® cricothyroidotomy insufflation device); and subsequently, a scalpel-bougie technique (surgical incision, bougie insertion into trachea and then tracheal tube passed over bougie, with ventilation using a self-inflating bag). The primary end-point was time from declaration of 'cannot intubate, cannot oxygenate' to delivery of oxygen via a correctly placed percutaneous device. If a cannula or tracheal tube was not placed within 240 s, the attempt was marked as a failure. There was one failure for the cannula approach and 15 for the scalpel-bougie technique (OR 0.07 (95%CI 0.00-0.43); p <0.001). Median (IQR [range]) time to oxygenation, if successful, was 65 (57-78 [28-160]) s for the cannula approach and 90 (74-115 [40-265]) s for the scalpel-bougie technique (p=0.005). In this ovine model, emergency front-of-neck access using a cannula had a lower chance of failure and (when successful) shorter time to first oxygen delivery compared with a scalpel-bougie technique.

Human influence on the terrestrial biota and biotic communities of New Zealand.

Alien plants and animals are of major economic and conservation significance in New Zealand. Plant introductions have averaged 11 species per year since European settlement in /840, and distinctive landscapes are being increasingly altered by weeds. Many introduced animals act as disease vectors or threaten native biota. Recent studies of introduced wasps show adverse effects on honey-eating and insectivorous birds. Introduced possums are now known to prey on eggs and nestlings of native birds in addition to their impact on native forests and transmittal of bovine tuberculosis. Research is increasingly focused on finding effective methods of biocontrol.