How can a rescuer prevent secondary drownings?

A rescuer can effectively prevent secondary drownings by ensuring that victims receive a medical evaluation following their rescue from the water. Secondary drowning occurs when water that has entered the lungs causes complications after initial rescue, and symptoms may not appear immediately. Victims may feel fine initially but can develop respiratory issues later due to inhaled water affecting lung function. By ensuring a medical evaluation, rescuer can identify any potential complications early and provide necessary treatment to mitigate risks, thus significantly reducing the likelihood of secondary drowning.

The other choices do not provide adequate measures for preventing secondary drowning. Leaving a victim alone does not allow for monitoring of any developing symptoms, and rushing food or drink without proper medical assessment can pose further risks to someone who may have compromised lung function. Providing a blanket, while potentially useful for warmth, does not address the underlying concerns related to water inhalation and respiratory distress. Therefore, prioritizing a medical evaluation is the most effective strategy.