What symptom indicates the usage of Treatment Table 6a?

Treatment Table 6a is specifically indicated for cases where symptoms remain unchanged or worsen during treatment at 60 feet when using oxygen. This scenario typically reflects a condition that requires a higher level of intervention or an adjustment in treatment strategy, as it suggests that the standard treatment procedures at that depth are not effective for the patient's situation.

For effective treatment of decompression sickness, the expectation is that symptoms should generally improve with appropriate oxygen therapy; therefore, if they do not, this is a critical sign for clinicians to escalate care or modify the treatment protocol. Treating with hyperbaric oxygen is designed to alleviate the symptoms of decompression sickness and related conditions, but the persistence or worsening of symptoms at this stage indicates that there is a need to adjust the therapeutic approach.

The other choices reflect situations that do not warrant the application of Treatment Table 6a. For instance, improvement in symptoms at 60 feet indicates that the treatment is working and does not necessitate a transition to Table 6a, symptomatic omitted decompression may suggest a different management scenario, and marbling of the skin is a specific sign that may correspond to other conditions but does not directly relate to the decision to use Treatment Table 6a within this context.