Comparison of the Effects of Normocapnia and Mild Hypercapnia on the Optic Nerve Sheath Diameter and Regional Cerebral Oxygen Saturation in Patients Undergoing Gynecological Laparoscopy with Total Intravenous Anesthesia

Abstract

Cerebral hemodynamics may be altered by hypercapnia during a lung-protective ventilation (LPV), CO2 pneumoperitoneum, and Trendelenburg position during general anesthesia. The purpose of this study was to compare the effects of normocapnia and mild hypercapnia on the optic nerve sheath diameter (ONSD), regional cerebral oxygen saturation (rSO2), and intraoperative respiratory mechanics in patients undergoing gynecological laparoscopy under total intravenous anesthesia (TIVA). Sixty patients (aged between 19 and 65 years) scheduled for laparoscopic gynecological surgery in the Trendelenburg position. Patients under propofol/remifentanil total intravenous anesthesia were randomly assigned to either the normocapnia group (target PaCO2 = 35 mmHg, n = 30) or the hypercapnia group (target PaCO2 = 50 mmHg, n = 30). The ONSD, rSO2, and respiratory and hemodynamic parameters were measured at 5 min after anesthetic induction (Tind) in the supine position, and at 10 min and 40 min after pneumoperitoneum (Tpp10 and Tpp40, respectively) in the Trendelenburg position. There was no significant intergroup difference in change over time in the ONSD (p = 0.318). The ONSD increased significantly at Tpp40 when compared to Tind in both normocapnia and hypercapnia groups (p = 0.02 and 0.002, respectively). There was a significant intergroup difference in changes over time in the rSO2 (p < 0.001). The rSO2 decreased significantly in the normocapnia group (p = 0.01), whereas it increased significantly in the hypercapnia group at Tpp40 compared with Tind (p = 0.002). Alveolar dead space was significantly higher in the normocapnia group than in the hypercapnia group at Tpp40 (p = 0.001). In conclusion, mild hypercapnia during the LPV might not aggravate the increase in the ONSD during CO2 pneumoperitoneum in the Trendelenburg position and could improve rSO2 compared to normocapnia in patients undergoing gynecological laparoscopy with TIVA.

Evaluation of the relationship between intraoperative cerebral oxygen saturation and postoperative cognitive functions in laparoscopic hysterectomy surgery

“…On the other hand, cerebral oxygenation is impaired when hypercapnic. [28] In our study, while carbon dioxide monitoring was not performed, no deterioration in cerebral oxygenation occurred in any of the patients. Finally, although the patient was treated to provide pain control during postoperative care, the data of the patients for this period were not examined.…”

Impact of Remimazolam versus Sevoflurane Anesthesia on Cerebral Oxygenation and Intracranial Pressure during Gynecological Laparoscopy with Mild Hypercapnia

“…In a previous clinical study on changes in rSO 2 during pneumoperitoneum in the Trendelenburg position under propofol anesthesia, rSO 2 changed along with changes in MAP and PaCO 2 , but not in HR, PaO 2 , or SaO 2 [ 3 ]. Mild hypercapnia seems to improve rSO 2 regardless of the anesthetic agents [ 5 , 15 ]. Mild hypercapnia during laparoscopic gynecological surgery with total intravenous anesthesia using propofol and remifentanil showed improved rSO 2 values compared with those in the normocapnia group [ 5 ].…”

“…Mild hypercapnia seems to improve rSO 2 regardless of the anesthetic agents [ 5 , 15 ]. Mild hypercapnia during laparoscopic gynecological surgery with total intravenous anesthesia using propofol and remifentanil showed improved rSO 2 values compared with those in the normocapnia group [ 5 ]. In addition, in major surgeries using sevoflurane, the mild hypercapnia group showed a stable increase in rSO 2 , whereas the normocapnia group showed a decrease in rSO 2 [ 15 ].…”

“…The primary outcome was the difference in rSO 2 during pneumoperitoneum, and the secondary outcome was the difference in ONSD changes during surgery. The sample size was calculated based on a previous study [ 5 ] that compared the rSO 2 between mild hypercapnia and normocapnia during total intravenous anesthesia. When rSO 2 was 72.9±8.3 during pneumoperitoneum in the Trendelenburg position during mild hypercapnia [ 5 ], 31 participants were required for each group considering a power of (1−β) of 90% and an α-error of 0.05 with 10% of possible drop-outs.…”

“…Rather than overcorrection of hypercapnia, a previous study showed that permissive hypercapnia, a part of lung-protective ventilation, improves respiratory function after laparoscopic surgery [ 4 ]. Although hypercapnia is well known to induce cerebral vasodilation and increase ICP, previous studies that used propofol/remifentanil total intravenous anesthesia have shown that mild hypercapnia does not exacerbate the increase in ONSD during pneumoperitoneum in the Trendelenburg position but rather improves rSO 2 compared with normocapnia [ 5 ].…”