However, in the case of immobilization of the cervical spine, it is impossible to perform "sniffing position" during intubation, and visualization of the glottis may be difficult or impossible to perform.
The requirement to rotate the machine at high speeds is an obstacle in many cases, where it is impossible to perform measurements at high speeds, due to harsh conditions such as high temperatures and inaccessibility (e.g., jet engines).
On occasion, it is impossible to perform ERCP with a traditional duodenoscope in patients who have had a Billroth II gastrectomy or hepatojejunostomy, and who now have biliary tract problems.
Today, we know that it is impossible to perform a complete Bell-state measurement using only linear optics7 (for which the intensity of light is not high enough for photon creation to occur).
Perhaps, he concedes, it is impossible to perform so painful a task with someone so young, someone who is, as his wife puts it in the book's afterword, so unwilling to let go.
He makes his work with so much humanity, and demands such honesty and truth from his dancers, that it is impossible to perform his pieces without reaching deep inside yourself and drawing on your personal experience.
