Which intervention is most critical for the nurse to implement for a client after a snow-skiing accident?

In the context of a client who has experienced a snow-skiing accident, the most critical intervention would be to review the electrocardiogram tracing. This step is essential because traumatic injuries from skiing can lead to various complications, including cardiovascular changes due to shock, blood loss, or potential injuries to the thoracic area that could affect heart function.

By assessing the electrocardiogram, the nurse can identify any abnormal heart rhythms, which can indicate complications such as arrhythmias or ischemia. Early detection of these issues is crucial in guiding further interventions and ensuring appropriate and timely care to mitigate any risk of cardiac complications.

While the other interventions may also be relevant in the overall management of the client, they do not address immediate life-threatening concerns as directly as monitoring the heart's electrical activity does. Coagulation studies and warming measures, although important, would follow the priority of ensuring cardiovascular stability. Thus, reviewing the electrocardiogram is pivotal in the immediate care of the patient following a ski accident.