Purpose: Pneumoperitoneum during laparoscopic abdominal surgery increases intra-abdominal pressure (IAP), potentially altering intracranial pressure (ICP) and cerebral oxygenation, with unclear implications for early postoperative cognitive dysfunction (POCD). Optic nerve sheath diameter (ONSD) via ultrasonography and near-infrared spectroscopy (NIRS) based cerebral oximetry offer non-invasive monitoring tools to assess these changes.
In this prospective observational study, fifty ASA I-III patients (20-60 years) undergoing elective laparoscopic abdominal surgery under general anesthesia were enrolled. Serial measurements of bilateral ONSD and regional cerebral oxygen saturation (rSO2, NIRS) were obtained at five perioperative time points: before induction (T0), 5 minutes post-induction (T1), 5 minutes after CO2 pneumoperitoneum (T2), 30 minutes after pneumoperitoneum (T3), and 5 minutes post-desufflation (T4). IAP was measured both intravesically and via insufflator readings. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) preoperatively and at 24 hours postoperatively. Hemodynamic parameters and airway pressures were recorded concurrently.
Study Type
OBSERVATIONAL
Enrollment
50
All parameters (ONSD, rSO2, IAP, EtCO2, Ppeak, SBP, DBP, MAP, HR) were recorded at:T0: Pre-induction baseline,T1: 5 min after induction,T2: 5 min after COpneumoperitoneum,T3: 30 min after pneumoperitoneum,T4: 5 min post-desufflation. ONSD was measured using a high-frequency (18 MHz) linear ultrasound probe (Mylab 5, Esaote, Genoa, Italy). The ONSD was defined as the distance between the outer edges of the optic nerve sheath 3 mm posterior to the optic disc. rSO2 was measured continuously using NIRS (INVOS 4100) with bilateral frontal sensors. MMSE, administered in a face-to-face format by a trained researcher on the day before surgery (baseline) and 24 hours postoperatively. A decline of ≥2 points in the postoperative score compared to baseline was considered indicative of postoperative cognitive dysfunction (POCD).
Duzce University Medicine School, Anesthesiology and Reanimation Department
Düzce, Turkey (Türkiye)
Optic nerve sheath diameter (ONSD)
ONSD was measured by a single trained anesthesiologist using a high-frequency (18 MHz) linear ultrasound probe (Mylab 5, Esaote, Genoa, Italy). With patients in the supine position and eyelids closed, the probe was gently placed on the upper eyelid in horizontal and vertical planes without exerting pressure. The ONSD was defined as the distance between the outer edges of the optic nerve sheath 3 mm posterior to the optic disc.
Time frame: • T0: Pre-induction baseline • T1: 5 minutes after induction • T2: 5 minutes after CO pneumoperitoneum • T3: 30 minutes after pneumoperitoneum • T4: 5 minutes post-desufflation
postoperative cognitive dysfunction
Cognitive performance was evaluated using the Mini-Mental State Examination (MMSE), administered in a face-to-face format by a trained researcher on the day before surgery (baseline) and 24 hours postoperatively.The Mini Mental State Examination (MMSE) test consists of 11 questions and is evaluated from a minimum score of 0 to a maximum of 30, below 24 point is considered worse outcome, while a decline of ≥2 points in the postoperative score compared to baseline was considered indicative of postoperative cognitive dysfunction (POCD), consistent with prior studies.
Time frame: Time 1: Preoperative one day before Time 2: Postoperative 24 hours
cerebral oxygenation
Regional cerebral oxygen saturation (rSO2) was measured continuously using near-infrared spectroscopy (NIRS; INVOS 4100, Medtronic, Minneapolis, MN, USA) with bilateral frontal sensors.
Time frame: T0: Pre-induction baseline • T1: 5 minutes after induction • T2: 5 minutes after CO pneumoperitoneum • T3: 30 minutes after pneumoperitoneum • T4: 5 minutes post-desufflation
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