For a drowning patient in water less than 43 degrees F who has arrested, when is survival not likely?

In the context of drowning patients, particularly those submerged in cold water, hypothermia plays a significant role in outcomes. Water temperatures below 43 degrees Fahrenheit can induce profound hypothermia, which can slow the metabolic processes in the body significantly.

When someone experiences a drowning incident in such cold water, cold-related physiological responses can occur that protect the brain and other vital organs for a longer duration than might typically be expected. This is often referred to as the "lowering of the metabolic rate," which can allow for some degree of survival even after prolonged cardiac arrest, provided immediate resuscitation efforts are attempted.

Research indicates that in cases of drowning in cold water, survival is still possible up to 90 minutes after cardiac arrest, provided the patient is rescued and treated with appropriate care. After this window, particularly after 90 minutes, the likelihood of successful resuscitation and meaningful recovery diminishes significantly. Therefore, the point at which survival is considered unlikely in such clinical scenarios is typically around 90 minutes, as this duration exceeds the threshold for effective resuscitation in the context of drowning in cold water.