The nurse is caring for a patient in the sleep lab. Which assessment finding indicates to the nurse that the patient is in stage 4 NREM?

Choice A reason: Stage 4 NREM (deep sleep) is characterized by slow delta brain waves, making the patient difficult to awaken. This stage promotes physical restoration, with minimal responsiveness to stimuli. The assessment finding aligns with the physiological state of deep sleep, making it the correct indicator for stage 4 NREM. Choice B reason: Elevated vital signs are not typical of stage 4 NREM, where metabolic rate and heart rate decrease due to deep relaxation. Elevated vital signs may occur in REM or lighter sleep stages, making this finding inconsistent with the characteristics of deep NREM sleep. Choice C reason: Easily awakening occurs in lighter NREM stages (1 or 2), not stage 4, which is the deepest sleep phase. Patients in stage 4 require significant stimuli to rouse, so this finding contradicts the expected state of deep sleep, making it incorrect. Choice D reason: Rapid eye movement is specific to REM sleep, not NREM. Stage 4 NREM involves slow brain waves and no eye movement, focusing on physical restoration. This finding is characteristic of a different sleep phase, making it an incorrect indicator for stage 4 NREM.