The Effect of Optic Nerve Diameter on Postoperative Cognitive Function in Laparoscopic Hysterectomy
Condition: Intracranial Pressure Increase; Postoperative Cognitive Dysfunction
MeSH terms: Intracranial Hypertension; Postoperative Cognitive Complications; Cognitive Dysfunction
Study type: Interventional

Summary: 
      Prospective study, 40 patients ASA 2-3, 30-75 years old who were planned for laparoscopic
      hysterectomy operation will be included.One day before the operation and postoperative 1.3.7.
      A mini mental assessment test will be performed on these days.Standard monitoring and
      Near-Infrared Spectroscopy monitoring to measure cerebral oxygen saturation will be performed
      on the patients.NIRS sensors will be placed on the right and left sides of the forehead, 2 cm
      above the eyebrow, before induction of anesthesia. Before the induction of anesthesia, the
      measurement will begin and the FiO2 (fraction of inspiration oxygen) will be kept at
      60%.General anesthesia induction will be made with propofol 2mg/kg, remifentanil 0.5 µg/kg
      and rocuronium 0.6mg/kg, and maintenance will be provided with 2% sevoflurane.The patient
      will be intubated and ventilation support will be provided so that the tidal volume is 6-8
      ml/kg and the end tidal CO2 is 30-40 mmHg. PEEP (Positive end expiratory pressure) will not
      be applied to any patient. Intra-abdominal pressure will be maintained at 15 mmHg. All
      patients will be given 1gr paracetamol and 100mg tramadol for postoperative analgesia.During
      the measurement of optic nerve diameter, a layer of sterile water-soluble gel will be applied
      on the closed eyelid with a linear 10-5 MHz ultrasound probe. In our study, ONSDs of all
      patients will be measured by the same experienced anesthetist. Measurements will be made at 5
      different times. 5 minutes after induction of anesthesia in the supine position (T0), 5
      minutes after the onset of pneumoperitoneum (T1), 5 minutes after the upright trendelenburg
      position (T2), at the 2nd hour of the trendelenburg position (T3) and 5 minutes after
      returning to the supine position at the end of the surgery (T4) .ONSD measurements of the
      patients measured at 5 different times, peroperative NIRS values, peroperative SpO2, mean
      blood pressure, peak heart rate, anesthesia time, surgery time, time to stay in the
      trendelenburg position, partial oxygen saturation (PaO2), PCO2, end-tidal carbon dioxide
      (ETCO2) and peak airway pressure (pPEAK) will be recorded.
    

Detailed description: 
      To show whether the relationship between increased intracranial pressure and optic nerve
      diameter after long (> 2.5 hours) Trendelenburg laparoscopic hysterectomies has an effect on
      postoperative cognitive functions.

      Laparoscopic surgery has been developing rapidly in recent years. The fact that the bleeding
      risk and hospital stay are less, less pain, faster return to normal work, better cosmetic
      results and superior patient morbidity have made laparoscopic interventions more preferable
      (1). CO2 pneumoperitoneum and upright upside-down position (Trendelenburg position) are
      applied to patients who will undergo laparoscopic surgery for better visualization of the
      surgical field. However, the combined use of the pneumoperitoneum and trendelenburg position
      causes an increase in intraabdominal pressure, which triggers many systemic physiological
      changes, along with a decrease in venous return, and increases cerebral blood flow,
      intracranial pressure, and intraocular pressure (2,3).

      Optic nerve sheath diameter (ONSD), determined by non-invasive ocular sonography, is a simple
      and reliable method that is an indicator of increased intracranial pressure (ICP) in patients
      (4). Studies have found 100% sensitivity and specificity in the prediction that if ONSD is
      >5.5, ICP will be >20 mmHg (5,6).

      The effect of ONSD on postoperative delirium or postoperative cognitive dysfunction has not
      been fully explained in the literature. The aim of our study; To show whether the
      relationship between increased intracranial pressure and ONSD after long-lasting (>2.5 hours)
      Trendelenburg laparoscopic hysterectomies has an effect on postoperative cognitive functions.

      In this prospective and observational study, 40 patients ASA 2-3, 30-75 years old who were
      planned for laparoscopic hysterectomy operation will be included. Patients with a previous
      history of ocular disease, ocular surgery, neurological disease and transient ischemic attack
      will be excluded from the study. Cases returning to open surgery will be excluded from the
      study. One day before the operation and postoperative 1.3.7. A mini mental assessment test
      (MMSE-Mini Mental State Examination) will be performed on these days.

      Standard monitoring (electrocardiography-ECG, pulse oximetry, noninvasive arterial blood
      pressure) and Near-Infrared Spectroscopy (NIRS) monitoring to measure cerebral oxygen
      saturation will be performed on the patients. NIRS sensors will be placed on the right and
      left sides of the forehead, 2 cm above the eyebrow, before induction of anesthesia. Before
      the induction of anesthesia, the measurement will begin and the FiO2 (fraction of inspiration
      oxygen) will be kept at 60%. If cerebral oxygen decreases by more than 20% or is below 50%
      absolute, position will be changed or FiO2 will be increased.

      General anesthesia induction will be made with propofol 2mg/kg, remifentanil 0.5 µg/kg and
      rocuronium 0.6mg/kg, and maintenance will be provided with 2% sevoflurane. The patient will
      be intubated and ventilation support will be provided so that the tidal volume is 6-8 ml/kg
      and the end tidal CO2 is 30-40 mmHg. PEEP (Positive end expiratory pressure) will not be
      applied to any patient. Intra-abdominal pressure will be maintained at 15 mmHg. All patients
      will be given 1gr paracetamol and 100mg tramadol for postoperative analgesia.

      During the measurement of optic nerve diameter, a layer of sterile water-soluble gel will be
      applied on the closed eyelid with a linear 10-5 MHz ultrasound probe. In our study, ONSDs of
      all patients will be measured by the same experienced anesthetist.

      SPSS 21.0 computer program will be used for statistical analysis. Based on our pilot study
      data, a minimum sample size of 23 patients with 0.05 alpha and 90% power indicated that a
      sample size would be required.
    

Intervention name(s): measuring optic nerve diameter
Intervention type(s): Diagnostic Test
Intervention description(s): During the measurement of the optic nerve diameter, a layer of sterile water-soluble gel will be applied on the closed eyelid with a linear 10-5 MHz ultrasound probe.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: laparoscopic hysterectomy; trendelenburg position; optic nerve sheath diameter (ONSD); Mini Mental State Examination (MMSE); postoperative cognitive dysfunction