A Comparative Study of Ventilation Strategies in Different Surgical Positions on Intracranial Pressure and Cerebral Blood Flow During Laparoscopic Surgery

Overview

The purpose of this clinical trial is to investigate the effects of laparoscopic surgery in the Trendelenburg and Reverse Trendelenburg positions, and variable tidal volume ventilation (V-VCV), pressure-regulated volume-controlled ventilation (PRVC), conventional volume-controlled ventilation (C-VCV), and pressure-controlled ventilation (PCV) on esophageal pressure, airway pressure, tidal volume, intracranial pressure, and cerebral blood flow. The study aims to address the following primary questions:Does laparoscopic surgery in the Trendelenburg or Reverse Trendelenburg position increase esophageal pressure, airway pressure, and intracranial pressure, and decrease tidal volume and cerebral blood flow? Do variable tidal volume ventilation (V-VCV), pressure-regulated volume-controlled ventilation (PRVC), conventional volume-controlled ventilation (C-VCV), or pressure-controlled ventilation (PCV) increase esophageal pressure, airway pressure, and intracranial pressure, and decrease tidal volume and cerebral blood flow? The investigators will compare variable tidal volume ventilation (V-VCV), pressure-regulated volume-controlled ventilation (PRVC), conventional volume-controlled ventilation (C-VCV), and pressure-controlled ventilation (PCV) to determine which ventilation mode results in the least physiological disturbance for patients. Participant Procedures: Participants will: Be positioned according to the surgical requirements.Be randomly assigned to mechanical ventilation with either variable tidal volume ventilation (V-VCV), pressure-regulated volume-controlled ventilation (PRVC), conventional volume-controlled ventilation (C-VCV), or pressure-controlled ventilation (PCV). Undergo assessments at the following time points: immediately after endotracheal intubation, immediately after pneumoperitoneum, immediately after position change (Trendelenburg or Reverse Trendelenburg), 30 minutes after position change, and 1 hour after position change. Have their esophageal pressure, airway pressure, intracranial pressure, tidal volume, and internal jugular vein blood flow recorded at each assessment time point.

Interventions

• Other Variable tidal volume ventilation (V-VCV)
  Variable tidal volume ventilation (V-VCV) ：The initial tidal volume is set at 6-8 ml/kg IBW according to the Ideal Body Weight (IBW), and the maximum tidal volume (Vt\_max) and minimum tidal volume (Vt\_min) are set at 10-20% of the base tidal volume (Vt\_base). Respiratory Rate 12. Inspiratory Flow Rate (IFR) 60L/min, Inspiration to Expiration Ratio (IER) 1:2, Positive End-Expiratory Pressure (PEEP) 5 cm water column, and Inhaled Oxygen Concentration (FiO2) 41%.
• Other Pressure-regulated volume-controlled ventilation (PRVC)
  Pressure-regulated volume-controlled ventilation (PRVC) ：Initial tidal volume is set at 6-8 ml/kg IBW based on Ideal Body Weight (IBW), peak inspiratory pressure is capped at 30 cmH2O, maximum tidal volume (Vt\_max), and minimum tidal volume (Vt\_min) is set at 10-20% of basal tidal volume (Vt\_base). Respiratory Rate (RR) 12, Inspiratory Breathing Ratio (IBR) 1:2, Positive End-Expiratory Pressure (PEEP) 5 cm water column, and Inhaled Oxygen Concentration (FiO2) 98%.
• Other Conventional volume-controlled ventilation (C-VCV)
  Conventional volume-controlled ventilation (C-VCV) ：The initial tidal volume is set at 6-8 ml/kg IBW based on Ideal Body Weight (IBW), and the maximum tidal volume (Vt\_max) and minimum tidal volume (Vt\_min) are set at 10-20% of the basal tidal volume (Vt\_base). Respiratory Rate 12. Inspiratory Flow Rate (IFR) 60L/min, Inspiration to Expiration Ratio (IER) 1:2, Positive End-Expiratory Pressure (PEEP) 5cm water column, FiO2 98%.
• Other Pressure-controlled ventilation (PCV)
  Pressure-controlled ventilation (PCV)：Set inspiratory pressure level, usually 20 cmH2O initial value, Respiratory Rate 12, Inspiratory to Expiratory Ratio 1:2, Positive End-Expiratory Pressure (PEEP) 5 cm water column, Inhaled Oxygen Concentration (FiO2) 98%.
• Other Trendelenburg position
  Trendelenburg position：Lower the head of the bed by 30 degrees with no more than 15 degrees of lateral tilt.
• Other Reverse Trendelenburg position
  Reverse Trendelenburg position：Elevate the head of the bed by 30 degrees with no more than 15 degrees of lateral tilt.

Primary outcome measures

• esophageal pressure [Time frame: immediately after tracheal intubation]
• airway pressure [Time frame: immediately after tracheal intubation]
• intracranial pressure [Time frame: immediately after pneumoperitoneum]
• tidal volume [Time frame: immediately after tracheal intubation]
• carotid blood flow [Time frame: half an hour after change of position]

Eligibility criteria

Inclusion criteria

• Age: Unrestricted
• American Society of Anesthesiologists (ASA) Physical Status: Class I-III
• Surgical Position: Requires the use of either the Trendelenburg position or the Reverse Trendelenburg position during the procedure.
• Ventilation: Planned mechanical ventilation is required during the procedure, with suitability for one of the following modes: pressure-regulated volume-controlled ventilation (PRVC), conventional volume-controlled ventilation (C-VCV), or pressure-controlled ventilation (PCV).

Exclusion criteria

• Significant Cardiopulmonary Disease:
• Intracranial Disease
• Severe Coagulopathy or Current Anticoagulant Therapy
• Presence of Psychiatric Illness, Cognitive Impairment, or other condition that precludes the ability to understand or comply with the study.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Other

Study locations

China · 1 center

• Inner Mongolia Baogang Hospital — Baotou

Identifiers

NCT: NCT06805747 · 2024-MER-312

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗