Comparison of the Effects of Individualized PEEP Titration Versus Standard PEEP on Transcranial Doppler-Measured Cerebral Hemodynamic Parameters and Postoperative Neurocognitive Functions in Patients Undergoing Robotic Prostatectomy in the Trendelenburg Position
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 45
- 试验地点
- 1
- 主要终点
- Change in Noninvasive Estimated Intracranial Pressure
研究概览
简要总结
This randomized clinical trial will compare two approaches to setting positive end-expiratory pressure (PEEP) during robot-assisted radical prostatectomy performed in the Trendelenburg position. The study aims to determine whether individualized PEEP, selected according to the lowest driving pressure, affects cerebral blood flow and brain oxygenation differently from standard PEEP.
Approximately 45 adult patients undergoing robot-assisted radical prostatectomy will be randomly assigned to receive either individualized PEEP or standard PEEP during general anesthesia. Cerebral blood flow will be assessed noninvasively using transcranial Doppler ultrasound, and brain oxygenation will be monitored using near-infrared spectroscopy. Participants will also undergo brief assessments of attention, cognitive function, delirium, and sedation before and after surgery, with follow-up continuing for up to 48 hours after the operation.
Both ventilation approaches are routinely used in clinical practice, and no experimental drug, device, or additional invasive procedure will be used as part of the study.
详细描述
This single-center, prospective, randomized, parallel-group clinical trial will evaluate the effects of individualized positive end-expiratory pressure (PEEP) titration compared with standard fixed PEEP on cerebral hemodynamics during robot-assisted laparoscopic radical prostatectomy performed in steep Trendelenburg position with pneumoperitoneum.
Approximately 45 adult patients aged 18-80 years with American Society of Anesthesiologists (ASA) physical status I-III who are scheduled for robot-assisted laparoscopic radical prostatectomy will be randomized in a 1:1 ratio to either an individualized PEEP group or a standard PEEP group. All patients will receive standardized general anesthesia and volume-controlled ventilation. Ventilation will initially be set with a tidal volume of 8 mL/kg predicted body weight, an inspiratory-to-expiratory ratio of 1:2, and an inspired oxygen fraction of 0.40, with end-tidal carbon dioxide maintained at 35-40 mmHg.
In the standard PEEP group, PEEP will be maintained at 6 cmH2O following a recruitment maneuver. In the individualized PEEP group, a decremental PEEP titration will be performed after recruitment. PEEP will be decreased from 15 to 5 cmH2O in 1-cmH2O steps, and respiratory mechanics will be assessed after 12 respiratory cycles at each level. The PEEP level associated with the lowest driving pressure will be selected as the individualized PEEP and maintained during the relevant intraoperative period.
Cerebral hemodynamics will be assessed using transcranial Doppler ultrasonography of the middle cerebral artery. Pulsatility index and resistance index will be recorded, and noninvasive estimated intracranial pressure will be calculated from the pulsatility index using the formula nICPPI = 10.93 × PI - 1.28. Transcranial Doppler measurements will be performed after anesthesia induction, 60 minutes after initiation of steep Trendelenburg position and pneumoperitoneum, and 10 minutes after termination of Trendelenburg position and pneumoperitoneum before emergence from anesthesia.
The primary outcome will be the between-group difference in the change in noninvasive estimated intracranial pressure from the post-induction measurement to the measurement obtained 60 minutes after initiation of Trendelenburg position and pneumoperitoneum (ΔnICPPI, T4-T2). Secondary assessments will include cerebral oxygenation measured using near-infrared spectroscopy, additional transcranial Doppler parameters, intraoperative hemodynamic and respiratory variables, and postoperative neurocognitive outcomes.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Triple (Participant, Investigator, Outcomes Assessor)
盲法说明
Participants, investigators not involved in administration of the assigned ventilation strategy, the transcranial Doppler operator, postoperative outcome assessors, and the statistician will be blinded to group allocation. The anesthesiologist responsible for implementing the assigned PEEP strategy will not be blinded because knowledge of group allocation is required to perform the intervention.
入排标准
- 年龄范围
- 18 Years 至 80 Years（Adult, Older Adult）
- 性别
- Male
- 接受健康志愿者
- 否
入选标准
- •Age 18 to 80 years American Society of Anesthesiologists (ASA) physical status I-III Scheduled for robot-assisted laparoscopic radical prostatectomy Provision of written informed consent
排除标准
- •Body mass index (BMI) >35 kg/m² History of surgery requiring at least 1 hour of mechanical ventilation within the previous 2 weeks Severe pulmonary disease New York Heart Association (NYHA) class III-IV heart failure Progressive neuromuscular disease Known cerebrovascular malformation Head or neck anatomical conditions preventing adequate transcranial Doppler ultrasonography Refusal to participate in the study Intraoperative conversion to open surgery
研究组 & 干预措施
Individualized PEEP Group
Patients assigned to this group will undergo a recruitment maneuver followed by decremental PEEP titration from 15 to 5 cmH2O in 1-cmH2O steps. After 12 respiratory cycles at each PEEP level, the PEEP associated with the lowest driving pressure will be selected and maintained.
干预措施: Individualized PEEP Titration (Other)
Standard PEEP Group
Patients assigned to this group will undergo a recruitment maneuver followed by standard fixed PEEP of 6 cmH2O during mechanical ventilation.
干预措施: Standard PEEP Group (Other)
结局指标
主要结局
Change in Noninvasive Estimated Intracranial Pressure
时间窗: After anesthesia induction and 60 minutes after initiation of steep Trendelenburg position and pneumoperitoneum
Noninvasive estimated intracranial pressure (nICPPI), expressed in mmHg, will be calculated from the middle cerebral artery pulsatility index (PI) measured by transcranial Doppler ultrasonography using the formula nICPPI = 10.93 × PI - 1.28. The outcome is the change in nICPPI from after anesthesia induction to 60 minutes after initiation of steep Trendelenburg position and pneumoperitoneum, calculated as the later value minus the post-induction value.
次要结局
- Middle Cerebral Artery Pulsatility Index(After anesthesia induction; 60 minutes after initiation of steep Trendelenburg position and pneumoperitoneum; and 10 minutes after termination of Trendelenburg position and pneumoperitoneum, before emergence from anesthesia)
- Middle Cerebral Artery Resistance Index(After anesthesia induction; 60 minutes after initiation of steep Trendelenburg position and pneumoperitoneum; and 10 minutes after termination of Trendelenburg position and pneumoperitoneum, before emergence from anesthesia)
- Regional Cerebral Oxygen Saturation Measured by Near-Infrared Spectroscopy(Before anesthesia induction; after anesthesia induction; 30 and 60 minutes after initiation of steep Trendelenburg position and pneumoperitoneum; immediately before termination of Trendelenburg position; and 10 minutes after termination, before emergence)
- Months Backward Test Performance Score(Preoperatively and at 12, 24, 36, and 48 hours after surgery)
- Nursing Delirium Screening Scale Total Score(In the post-anesthesia care unit or intensive care unit, and at 12, 24, 36, and 48 hours after surgery)
- Richmond Agitation-Sedation Scale Score(In the post-anesthesia care unit or intensive care unit, and at 12, 24, 36, and 48 hours after surgery)
研究者
Ezgi Budak Ozyalcın
Specialist Doctor
Istanbul University