This study focuses on patients in the Intensive Care Unit (ICU) who require unplanned invasive mechanical ventilation, which is a method of using a machine to help a person breathe. The goal of the study is to assess recovery from critical illness in these patients. The research compares the effects of using ketamine hydrochloride, an injectable medication, against a placebo.

Participants will receive either an infusion, which is a continuous flow of medicine through a vein, of the test medication or a sodium chloride solution. During the study, various health factors are monitored, including the use of norepinephrine or inotropes, which are medications used to support blood pressure and heart function. The study also looks at the presence of encephalopathy, a term used to describe changes in brain function such as coma or delirium, as well as the impact on kidney and liver health.

The course of the study involves tracking recovery over a period of several months. This includes monitoring the use of opioids and sedatives, which are medicines used to manage pain and sleep, and observing symptoms such as hallucinations, anxiety, depression, or post-traumatic stress disorder (PTSD). Information is collected to see how many days patients spend alive and at home, as well as how long they can breathe without the help of a machine.