Anesthesia, Prostate Cancer, Respiratory Mechanics
Conditions
Brief summary
Study Synopsis This protocol is formatted for ClinicalTrials.gov-style registration and manuscript-facing documentation. It is based on the uploaded Turkish ethics protocol and keeps the original core design: comparison of low-flow and minimal-flow sevoflurane anesthesia in robot-assisted laparoscopic radical prostatectomy. Background and Rationale Robot-assisted laparoscopic radical prostatectomy (RALRP) is increasingly preferred for localized prostate cancer because of lower blood loss, reduced transfusion requirements, shorter hospitalization, and lower complication rates compared with open surgery. However, RALRP requires carbon dioxide pneumoperitoneum and steep Trendelenburg positioning, both of which may adversely affect respiratory mechanics, gas exchange, and hemodynamic stability. Low-flow and minimal-flow anesthesia may improve humidification and warming of inspired gases, reduce inhalational agent consumption, decrease environmental waste, and potentially lower overall cost. Despite these theoretical and practical advantages, evidence remains limited regarding the physiologic safety and performance of minimal-flow sevoflurane anesthesia during long robotic pelvic surgery performed under pneumoperitoneum and steep Trendelenburg positioning. Accordingly, this randomized prospective trial will compare low-flow (1 L/min) and minimal-flow (0.5 L/min) sevoflurane anesthesia during RALRP with respect to respiratory parameters, arterial blood gas values, intraoperative oxygenation variables, anesthetic consumption, and selected postoperative biochemical markers.
Interventions
OTHERCommon Anesthetic Management
Standard intraoperative monitoring including BIS, pulse oximetry, temperature, and anesthesia workstation-derived respiratory variables. * Arterial blood gas sampling after intubation, before pneumoperitoneum, after pneumoperitoneum/positioning, hourly during pneumoperitoneum, at the end of pneumoperitoneum in supine position, and before extubation. * Routine safety limits on the anesthesia machine: end-tidal carbon dioxide upper alarm 45 mmHg, inspired oxygen lower alarm 35%, inspired carbon dioxide upper alarm 3 mmHg. * Routine device self-test each morning and between patients. * Minimal dead space strategy with avoidance of unnecessary circuit extension. * Close monitoring of soda lime; replacement if inspired carbon dioxide reaches 3 mmHg even without obvious color change. * If clinically necessary because of blood gas deterioration, BIS changes, or any safety concern, fresh gas flow may be increased and the participant may be withdrawn from the protocol intervention.
Sponsors
Ankara City Hospital Bilkent
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
SUPPORTIVE_CARE
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Male patients aged 18 years or older. * ASA physical status I-II. * Scheduled for elective robot-assisted laparoscopic radical prostatectomy. * Provision of written informed consent.
Exclusion criteria
* ASA physical status III-V. * Severe cardiac, respiratory, hepatic, or renal disease. * Mental status disorder or significant hearing impairment that prevents consent or communication. * Known anxiety, depression, or other psychiatric disorder judged to interfere with study participation. * Withdrawal of consent or investigator decision for safety reasons.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Arterial partial pressure of carbon dioxide (PaCO₂) | intraoperative period, from post-intubation to before extubation on the day of surgery | Comparison of arterial PaCO₂ values between the minimal-flow anesthesia group (0.5 L/min) and the low-flow anesthesia group (1 L/min) measured during robot-assisted laparoscopic radical prostatectomy. Arterial blood gas analysis will be performed at predefined intraoperative time points (T0: post-intubation, T1: before pneumoperitoneum, T2: after pneumoperitoneum and positioning, hourly during pneumoperitoneum, at the end of pneumoperitoneum, and before extubation). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| End-tidal carbon dioxide (EtCO₂) | intraoperatively | Comparison of end-tidal CO₂ levels between the minimal-flow and low-flow anesthesia groups during surgery. |
| Oxygenation parameters | Intraoperative period (T0-Text). | Peripheral oxygen saturation (SpO₂) and arterial oxygen partial pressure (PaO₂) measured to evaluate intraoperative oxygenation. |
| Inhalational anesthetic consumption | Postextubation | Total sevoflurane consumption recorded from the anesthesia machine at the end of surgery. |
Outcome results
None listed