Advanced Cardiovascular Life Support (ACLS) Practice Exam

The presence of rigor mortis is a significant indicator that the patient has undergone complete and irreversible death. In the context of resuscitation, once rigor mortis has developed, it signifies that the body's physiological processes have ceased and resuscitation efforts are no longer effective or appropriate. This condition typically develops several hours post-mortem, indicating that the individual cannot be revived.

In contrast, significant improvement in vital signs, return of spontaneous circulation, and patient responsiveness to stimuli all indicate that the patient is either improving or has potentially regained a viable physiological state that could be compatible with survival. Thus, these signs would not warrant stopping resuscitation efforts but rather suggest that they should continue.