Effects Of Anaesthesia on Intraocular Pressure in Robotic Prostate Surgery

Ataturk Training and Research Hospital60 enrolled

Overview

Robot-assisted surgery is now commonly used to treat prostate cancer. This type of surgery, called robot-assisted prostatectomy, helps doctors operate more precisely and allows patients to heal faster. But there are some special things to be careful about during these surgeries. During the operation, the patient is placed in a steep head-down position for a long time. Staying in this position for a long period can cause the pressure inside the eyes-called intraocular pressure (IOP)-to go up. High eye pressure can be risky, especially for people who already have eye problems. This study looked at different types of anesthesia used during robotic prostate surgery to see how they affect eye pressure. The goal was to find out which type of anesthesia causes less of an increase in eye pressure.

In this study, the aim was to investigate the effects of hemodynamic changes induced by the steep Trendelenburg position and pneumoperitoneum, surgical duration, blood gas parameters, and the type of anesthesia administered on intraocular pressure (IOP) during robotic prostatectomy. Prostate cancer is the most common type of cancer among men. Among the various treatment options, robot-assisted radical prostatectomy (RARP) stands out as the most recent and technologically advanced surgical approach. This randomized and prospective study was conducted at the operating rooms of Ankara Atatürk Training and Research Hospital following approval by the Ethics Committee. Sixty cooperative adult male patients scheduled to undergo robotic prostatectomy under general anesthesia and classified as ASA physical status I-II were enrolled in the study after providing informed written consent. Patients with severe cardiac disease, restrictive or obstructive pulmonary disease, renal or hepatic insufficiency, a history of hypersensitivity to anesthetic agents, psychiatric disorders, neurologic diseases, previous intracranial surgery, chronic alcohol, sedative, tranquilizer, or analgesic use, glaucoma, or those receiving medications known to affect IOP, as well as patients predicted to present with difficult intubation on direct laryngoscopy, were excluded from the study. Participants were randomly assigned to one of two groups by drawing a label from a sealed envelope: Group 1 received inhalation anesthesia, and Group 2 received total intravenous anesthesia (TIVA). Demographic data were recorded. Prior to the induction of general anesthesia, while the participants were in the supine position, baseline measurements were taken, including heart rate (HR), mean arterial pressure (MAP), peripheral oxygen saturation (SpO₂), end-tidal CO₂ (ETCO₂), bispectral index (BIS), and IOP in both eyes. Anesthesia induction was carried out using the following agents: patients in Group 1 received intravenous Lidocaine at a dose of 1-1.5 mg/kg, Thiopental 4-6 mg/kg, Remifentanil 1 µg/kg, and Rocuronium 0.6-1.2 mg/kg. In Group 2, Lidocaine 1-1.5 mg/kg, Propofol 2-3 mg/kg, Remifentanil 1 µg/kg, and Rocuronium 0.6-1.2 mg/kg were administered. For anesthesia maintenance, Group 1 was managed with Sevoflurane combined with a Remifentanil infusion, while Group 2 received a combination of Propofol and Remifentanil infusions. Intraocular pressure (IOP), hemodynamic parameters, arterial blood gas values, pulmonary mechanics, heart rate (HR), mean arterial pressure (MAP), systolic and diastolic blood pressure, bispectral index (BIS), peripheral oxygen saturation (SpO₂), and end-tidal carbon dioxide (ETCO₂) levels were evaluated at ten specific time points throughout the procedure. These included: before anesthesia induction (T0); 10 minutes after induction (T1); 2 minutes after positioning the participant in the steep Trendelenburg position (T2); 2 minutes following carbon dioxide (CO₂) insufflation (T3); 1 hour (T4), 2 hours (T5), and 3 hours (T6) after CO₂ insufflation; 2 minutes after CO₂ desufflation (T7); 2 minutes after returning the participant to the supine position (T8); and 45 minutes postoperatively (T9). Intra-abdominal pressures generated by CO₂ insufflation, as well as the minimum alveolar concentration (MAC) of sevoflurane and ETCO₂ values, were also recorded.

Interventions

Sevoflurane (Volatile Anesthetic)DRUG

Inhalational anesthetic used for maintenance of anesthesia. Administered at 2-3% concentration in a 40% oxygen-air mixture to maintain BIS values between 40-60.

Propofol 1%DRUG

Intravenous hypnotic agent used for induction (2-3 mg/kg) and maintenance (50-150 μg/kg/min) of anesthesia. Titrated to maintain BIS values between 40-60.

Remifentanil 2 MGDRUG

Short-acting opioid used for induction and maintenance of anesthesia at a dose of 1 μg/kg IV (induction) and 0.05-0.25 μg/kg/min (maintenance).

Rocuronium 50 mg/5 mlDRUG

Neuromuscular blocker administered IV at 0.6-1.2 mg/kg for induction and 0.15 mg/kg for maintenance of muscle relaxation during surgery.

Lidocaine %2 ampouleDRUG

Administered intravenously at 1-1.5 mg/kg before anesthesia induction to reduce injection pain and facilitate induction.

Thiopental 500 mg vial for injectionDRUG

Intravenous anesthetic agent used for induction of anesthesia at 4-6 mg/kg.

Neostigmine 0,5 mg/ml ampouleDRUG

Administered IV at 0.04 mg/kg for reversal of neuromuscular blockade at the end of the procedure.

Atropine Sulphate 0.5mg/ml ampouleDRUG

Administered intravenously (0.4 mg per 1 mg neostigmine) to counteract muscarinic effects during neuromuscular blockade reversal; also 0.5 mg IV in cases of intraoperative bradycardia (HR \< 45 bpm).

Ephedrine Hydrochloride 0,05 mg/ml ampouleDRUG

Used intravenously at 0.1 mg/kg to manage intraoperative hypotension unresponsive to fluid and anesthetic dose adjustment.

CO₂ PneumoperitoneumPROCEDURE

Creation of pneumoperitoneum with CO₂ insufflation for robotic prostatectomy; monitoring and recording of intra-abdominal pressures.

Bispectral index (BIS) MonitoringDEVICE

Monitoring of depth of anesthesia using bispectral index values; frontal placement preoperatively and throughout surgery. BIS maintained between 40-60.

intraocular pressure measurementPROCEDURE

Measurement of intraocular pressure (IOP) in both eyes at multiple intraoperative and postoperative time points (T0-T9).

intraarterial cannulation and pressure measurementPROCEDURE

Invasive arterial blood pressure measurement and blood gas measurements via an 18G catheter inserted into the radial artery

Mechanical VentilationPROCEDURE

Ventilation initiated after intubation with volume-controlled settings (TV 6-8 ml/kg, RR 12, FiO₂ 50%), adjusted to maintain ETCO₂ between 30-36 mmHg.

Peripheral Intravenous CannulationPROCEDURE

All participants received peripheral intravenous cannulation using 18-20 G IV cannulas placed on the dorsum of the hand before anesthesia induction.

Crystalloid solutionsDRUG

Participants received calculated maintenance fluids with crystalloids through intravenous infusion prior to and during surgery.

Endotracheal IntubationPROCEDURE

After induction of anesthesia and neuromuscular blockade, endotracheal intubation was performed using standard technique in all participants.

American Society of Anesthesiologists (ASA) Standard MonitorsPROCEDURE

Routine ASA monitoring, including noninvasive blood pressure, ECG (D2 derivation), End-tidal carbon dioxide (ETCO₂) and Peripheral Oxygen Saturation (SpO₂), was performed in all patients, starting from the preoperative period and continuing throughout the surgery.

Ventilatory Pressure and Compliance MonitoringPROCEDURE

Throughout the procedure, the following lung mechanics were continuously measured: PEEP, peak airway pressure (PEAK), mean airway pressure (Pmean), plateau pressure (Pplato), and dynamic compliance.

Outcomes

Primary Outcomes

Intraocular Pressure Measured Using Tono-Pen at Multiple Perioperative Time Points (mmHg)

Intraocular pressure (IOP) will be measured in both eyes using a handheld Tono-Pen tonometer at the following predefined perioperative time points: T0 (before anesthesia induction) T1 (10 minutes after induction) T2 (2 minutes after steep Trendelenburg positioning) T3 (2 minutes after carbon dioxide (CO₂) insufflation) T4 (1 hour after CO₂ insufflation) T5 (2 hours after CO₂ insufflation) T6 (3 hours after CO₂ insufflation) T7 (2 minutes after CO₂ desufflation) T8 (2 minutes after return to supine position) T9 (45 minutes postoperatively) The unit of measurement is mmHg at each time point. Each time point will be reported separately. To ensure consistency, all measurements will be performed by the same ophthalmologist.

Time frame: From 10 minutes before anesthesia induction to 45 minutes postoperatively

Secondary Outcomes

Heart Rate at Defined Perioperative Time Points (bpm)

Heart rate (HR) will be measured non-invasively using standard ASA monitoring equipment at the following perioperative time points: T0 (before anesthesia induction) T1 (10 minutes after induction) T2 (2 minutes after Trendelenburg positioning) T3 (2 minutes after carbon dioxide (CO₂) insufflation) T4 (1 hour after CO₂ insufflation) T5 (2 hours after CO₂ insufflation) T6 (3 hours after CO₂ insufflation) T7 (2 minutes after CO₂ desufflation) T8 (2 minutes after return to supine position) T9 (45 minutes postoperatively) Heart rate will be reported separately for each time point.