Transcranial Doppler and NIRS Monitoring of Cerebral Hemodynamics in Pediatric Laparoscopic Surgery

Laparoscopic surgery has become widely adopted in pediatric patients due to its minimally invasive nature, reduced postoperative pain, shorter hospital stay, and improved cosmetic outcomes. Laparoscopic inguinal hernia repair has been increasingly preferred over open techniques because of its potential advantages in surgical visualization and reduced complication rates. However, the establishment of pneumoperitoneum with carbon dioxide (CO₂) insufflation and the use of the Trendelenburg position are essential components of laparoscopic procedures and may lead to significant physiological changes.

The combination of pneumoperitoneum and Trendelenburg positioning can increase intra-abdominal pressure and central venous pressure, potentially resulting in elevated intracranial pressure and alterations in cerebral hemodynamics. These changes may influence cerebral perfusion and oxygenation during anesthesia. Increased intra-abdominal pressure may impair venous return from the brain, while changes in arterial carbon dioxide levels may contribute to cerebral vasodilation and further modify cerebral blood flow.

This prospective observational study aims to evaluate cerebral hemodynamic changes during pediatric laparoscopic inguinal hernia surgery using noninvasive neuromonitoring techniques. Transcranial Doppler ultrasonography (TCD) will be used to measure middle cerebral artery (MCA) flow velocities and pulsatility index (PI) as indirect indicators of intracranial pressure and cerebral blood flow dynamics. Cerebral oxygen saturation will be continuously monitored using near-infrared spectroscopy (NIRS).

Hemodynamic parameters including mean arterial pressure and end-tidal carbon dioxide (EtCO₂) will also be recorded to assess their relationship with cerebral hemodynamic changes.

Measurements will be performed at three predefined time points:

After induction of general anesthesia in the supine position,

Ten minutes after the establishment of pneumoperitoneum and placement in the Trendelenburg position,

Ten minutes before discontinuation of the inhalational anesthetic at the end of surgery.

The primary objective of the study is to evaluate changes in MCA flow velocity and pulsatility index during laparoscopic surgery. The secondary objective is to assess the relationship between cerebral oxygen saturation measured by NIRS and cerebral blood flow parameters obtained from TCD, as well as their association with mean arterial pressure and end-tidal CO₂.

Inclusion criteria

-Children aged 2-10 years

• Scheduled for elective laparoscopic inguinal hernia repair
• American Society of Anesthesiologists (ASA) physical status I-II
• Undergoing surgery under general anesthesia
• Written informed consent obtained from parent or legal guardian

Exclusion criteria

-Known neurological disorders

• Intracranial pathology that may increase intracranial pressure
• History of cerebrovascular disease
• Development of intraoperative hemodynamic instability
• Severe cardiac or respiratory disease
• Inability to perform transcranial Doppler measurements
• Parent or legal guardian declines participation