A 60-year-old male is brought to the emergency department after being rescued from a collapsed building. He was trapped under debris for several hours and is now complaining of severe muscle pain and weakness. His urine is dark colored. What is the most critical initial step in managing his condition?
Initiate aggressive fluid resuscitation
Provide pain management with opioid analgesics
Administer sodium bicarbonate to alkalinize the urine
Perform fasciotomy to relieve compartment syndrome