Postoperative cognitive dysfunction, or POCD, is a decline in thinking, memory, attention, or executive function that may occur after surgery and anesthesia. Patients undergoing open heart surgery with cardiopulmonary bypass may have a higher risk of POCD because of changes in blood flow, inflammation, microemboli, and changes in brain oxygen supply during surgery.

Cooling the head during open heart surgery may help protect the brain by reducing brain metabolism, oxygen demand, inflammation, and cellular injury. A cooling helmet is a non-invasive device placed on the patient's head during surgery. In this study, the cooling helmet is used to circulate cold water around the scalp during cardiopulmonary bypass.

The purpose of this study is to determine whether the use of a cooling helmet reduces the incidence of POCD in adult patients undergoing open heart surgery with cardiopulmonary bypass. The main question is whether patients who receive head cooling with a cooling helmet have a lower rate of POCD compared with patients who wear the same helmet with room-temperature water circulation.

This study is a single-blind randomized controlled trial evaluating the use of a cooling helmet as an additional neuroprotective strategy during open heart surgery with cardiopulmonary bypass. Postoperative cognitive dysfunction is an important neurologic complication after cardiac surgery and may affect memory, attention, executive function, recovery, independence, and quality of life.

During cardiopulmonary bypass, the brain may be exposed to several potential mechanisms of injury, including reduced cerebral perfusion, microemboli, systemic inflammation, changes in oxygen delivery, and temperature changes during cooling and rewarming. Mild hypothermia has been proposed as a neuroprotective strategy because lower temperature can reduce cerebral metabolic demand, oxygen consumption, excitotoxicity, inflammatory response, free radical production, and neuronal apoptosis.

The cooling helmet used in this study is a non-invasive head-cooling device designed to provide more even and continuous cooling than conventional external ice application. The device consists of water-filled tubing arranged around the head and connected to a pump and cooling box. In the intervention group, cold water is circulated through the helmet during cardiopulmonary bypass. In the control group, room-temperature water is circulated through the same helmet. Participants are blinded to group allocation.

Cognitive function is assessed before surgery and again after surgery using neurocognitive tests that evaluate memory, attention, and executive function. These include the Rey Auditory Verbal Learning Test, Digit Span Forward and Backward, and Trail Making Test A and B. POCD is determined by comparing postoperative neurocognitive performance with baseline performance before surgery.

Intraoperative monitoring includes standard anesthetic monitoring, cerebral regional oxygen saturation monitoring using near-infrared spectroscopy, and temperature monitoring using nasopharyngeal and rectal temperature probes. The study also observes potential side effects related to the cooling helmet, including cold-related skin injury and shivering.

This study is designed to clarify whether localized head cooling with a cooling helmet can reduce postoperative cognitive dysfunction in adults undergoing open heart surgery with cardiopulmonary bypass.

Inclusion Criteria:

• Scheduled to undergo open heart surgery using cardiopulmonary bypass.
• Age older than 18 years.
• American Society of Anesthesiologists (ASA) physical status III or IV.
• Fully conscious with Glasgow Coma Scale score of 15.
• Able to communicate in Indonesian.

Exclusion Criteria:

• Refusal to participate in the study.
• History of central nervous system disorder, such as stroke or intracranial tumor.
• History of psychiatric disorder.
• Severe cognitive impairment.
• Use of psychotropic or narcotic drugs.
• Blindness or hearing impairment.
• Uncooperative patient.

Individual participant data will not be shared. Participant data are kept confidential and are accessible only to the research team and ethics committee for verification purposes. Study results may be reported in aggregate form without identifying individual participants.

Participants were blinded to group allocation. Both groups wore the same cooling helmet during surgery; however, the intervention group received cold water circulation, while the control group received room-temperature water circulation.