Explanation

Medication errors, especially involving high-alert medications like heparin and significant dose discrepancies (a tenfold overdose in this case), pose the greatest immediate risk to client safety. This type of error requires immediate investigation to assess the client for adverse effects (e.g., bleeding), implement corrective actions (e.g., obtaining PTT levels, notifying the provider, administering protamine sulfate if needed), and identify system factors that contributed to the error to prevent recurrence.

A visitor slip without injury requires follow-up on environmental safety (wet floor signage/cleanup) but is less critical than a major medication error affecting a client. An unplugged call light is a safety concern that needs immediate correction but doesn't represent the same level of potential harm as the medication error. A routine medication administered 30 minutes late is generally considered a minor variance unless it involves a time-critical medication, and it poses less immediate risk than the heparin overdose.