The trial will accrue a maximum of 1408 patients. Patients will be recruited from the emergency departments, intensive care units and other acute care areas of the PETAL Network Clinical Centers and randomized to the active (NMB) or control. The overall strategy is to screen, consent, and enroll early, every newly intubated, acutely ill or post-operative, eligible patient at each site, using clinically obtained pulse oximetry and blood gases.