It remains to be elucidated whether the Trendelenburg position increases intracranial pressure (ICP). ICP can be evaluated by measuring the sonographic optic nerve sheath diameter (ONSD). We investigated the effect of the isolated Trendelenburg position on ONSD in patients undergoing robot-assisted laparoscopic radical prostatectomy. Additionally, we evaluated the effect of the Trendelenburg position combined with pneumoperitoneum on ONSD. Twenty-one patients scheduled for robot-assisted laparoscopic radical prostatectomy were enrolled. Sonographic ONSDs and hemodynamic parameters were measured at specific time points: in the supine position after induction of anesthesia, 3 min after the steep Trendelenburg position (35° incline), 3 min after the steep Trendelenburg position combined with pneumoperitoneum, and in the supine position after desufflation of the pneumoperitoneum. The ONSD 3 min after the steep Trendelenburg position was significantly higher than that of the supine position after induction of anesthesia (5.1 ± 0.3 mm vs. 4.5 ± 0.4 mm). In addition, the ONSD 3 min after the steep Trendelenburg position combined with pneumoperitoneum was higher than that of the supine position after induction of anesthesia (4.9 ± 0.4 mm vs. 4.5 ± 0.4 mm). The ONSD in the supine position after desufflation of the pneumoperitoneum was similar to that in the supine position after induction of anesthesia. Use of the isolated steep Trendelenburg position, for even a short duration, increased the sonographic ONSD, providing a better understanding of the effect of only a transient steep Trendelenburg position on ONSD as a surrogate measure for ICP.

Prediction of difficult airway is critical in the airway management of trauma patients. A LEMON method which consists of following assessments; Look-Evaluate-Mallampati-Obstruction-Neck mobility is a fast and easy technique to evaluate patients’ airways in the emergency situation. And a modified LEMON method, which excludes the Mallampati classification from the original LEMON score, also can be used clinically. We investigated the relationship between modified LEMON score and intubation difficulty score in adult trauma patients undergoing emergency surgery. We retrospectively reviewed electronic medical records of 114 adult trauma patients who underwent emergency surgery under general anesthesia. All patients’ airways were evaluated according to the modified LEMON method before anesthesia induction and after tracheal intubation; the intubating doctor self-reported the intubation difficulty scale (IDS) score. A difficult intubation group was defined as patients who had IDS scores > 5. The modified LEMON score was significantly correlated with the IDS score (P < 0.001). The difficult intubation group showed higher modified LEMON score than the non-difficult intubation group (3 [2-5] vs. 2 [1-3], respectively, P = 0.017). Limited neck mobility was the only independent predictor of intubation difficulty (odds ratio, 6.15; P = 0.002). The modified LEMON score is correlated with difficult intubation in adult trauma patients undergoing emergency surgery.

Rapid evaluation and management of intracranial pressure (ICP) can help to early detection of increased ICP and improve postoperative outcomes in neurocritically-ill patients. Sonographic measurement of optic nerve sheath diameter (ONSD) is a non-invasive method of evaluating increased intracranial pressure at the bedside. In the present study, we hypothesized that sonographic ONSD, as a surrogate of ICP change, can be dynamically changed in response to carbon dioxide change using short-term hyperventilation. Fourteen patients were enrolled. During general anesthesia, end-tidal carbon dioxide concentration (ETCO2) was decreased from 40 mmHg to 30 mmHg within 10 minutes. ONSD, which was monitored continuously in the single sonographic plane, was repeatedly measured at 1 and 5 minutes with ETCO2 40 mmHg (time-point 1 and 2) and measured again at 1 and 5 minutes with ETCO2 30 mmHg (time-point 3 and 4). The mean ± standard deviation of ONSD sequentially measured at four time-points were 5.0 ± 0.5, 5.0 ± 0.4, 3.8 ± 0.6, and 4.0 ± 0.4 mm, respectively. ONSD was significantly decreased at time-point 3 and 4, compared with 1 and 2 (P < 0.001). The ONSD was rapidly changed in response to ETCO2. This finding may support that ONSD may be beneficial to close ICP monitoring in response to CO2 change.

OBJECTIVE: Mannitol is used intraoperatively to induce brain relaxation in patients undergoing supratentorial brain tumor resection. The authors sought to determine the dose of mannitol that provides adequate brain relaxation with the fewest adverse effects.METHODS: A total of 124 patients were randomized to receive mannitol at 0.25 g/kg (Group A), 0.5 g/kg (Group B), 1.0 g/kg (Group C), and 1.5 g/kg (Group D). The degree of brain relaxation was classified according to a 4-point scale (1, bulging; 2, firm; 3, adequate; and 4, perfectly relaxed) by neurosurgeons; Classes 3 and 4 were considered to indicate satisfactory brain relaxation. The osmolality gap (OG) and serum electrolytes were measured before and after mannitol administration.RESULTS: The brain relaxation score showed an increasing trend in patients receiving higher doses of mannitol (p = 0.005). The incidence of satisfactory brain relaxation was higher in Groups C and D than in Group A (67.7% and 64.5% vs 32.2%, p = 0.011 and 0.022, respectively). The incidence of OG greater than 10 mOsm/kg was also higher in Groups C and D than in Group A (100.0% in both groups vs 77.4%, p = 0.011 for both). The incidence of moderate hyponatremia (125 mmol/L ≤ Na⁺ < 130 mmol/L) was significantly higher in Group D than in other groups (38.7% vs 0.0%, 9.7%, and 12.9% in Groups A, B, and C; p < 0.001, p = 0.008, and p = 0.020, respectively). Hyperkalemia (K⁺ > 5.0 mmol/L) was observed in 12.9% of patients in Group D only.CONCLUSIONS: The higher doses of mannitol provided better brain relaxation but were associated with more adverse effects. Considering the balance between the benefits and risks of mannitol, the authors suggest the use of 1.0 g/kg of intraoperative mannitol for satisfactory brain relaxation with the fewest adverse effects.Clinical trial registration no.: NCT02168075 (clinicaltrials.gov)

Robot-assisted laparoscopic prostatectomy (RALP) is a minimally invasive technique for the treatment of prostate cancer. RALP requires the patient to be placed in the steep Trendelenburg position, along with pneumoperitoneum, which may increase the risk of postoperative pulmonary complications (PPCs). This large single-center retrospective study evaluated the incidence and risk factors of PPCs in 2208 patients who underwent RALP between 2014 and 2017. Patients were divided into those with (PPC group) and without (non-PPC group) PPCs. Postoperative outcomes were evaluated, and univariate and multivariate logistic regression analyses were performed to assess risk factors of PPCs. PPCs occurred in 682 patients (30.9%). Risk factors of PPCs included age (odds ratio [OR], 1.023; p = 0.001), body mass index (OR, 1.061; p = 0.001), hypoalbuminemia (OR, 1.653; p = 0.008), and positive end-expiratory pressure (PEEP) application (OR, 0.283; p < 0.001). The incidence of postoperative complications, rate of intensive care unit (ICU) admission, and duration of ICU stay were significantly greater in the PPC group than in the non-PPC group. In conclusion, the incidence of PPCs in patients who underwent RALP under pneumoperitoneum in the steep Trendelenburg position was 30.9%. Factors associated with PPCs included older age, higher body mass index, hypoalbuminemia, and lack of PEEP.

During robot-assisted laparoscopic prostatectomy, specific physiological conditions such as carbon dioxide insufflation and the steep Trendelenburg position can alter the cardiac workload and cerebral hemodynamics. Inadequate arterial blood pressure is associated with hypoperfusion, organ damage, and poor outcomes. Dynamic arterial elastance (Ea) has been proposed to be a useful index of fluid management in hypotensive patients. We therefore evaluated whether dynamic Ea can predict a mean arterial pressure (MAP) increase ≥ 15% after fluid challenge during pneumoperitoneum and the steep Trendelenburg position. We enrolled 39 patients receiving robot-assisted laparoscopic prostatectomy. Fluid challenge was performed with 500 mL colloids in the presence of preload-dependent conditions and arterial hypotension. Patients were classified as arterial pressure responders or arterial pressure nonresponders according to whether they showed an MAP increase ≥15% after fluid challenge. Dynamic Ea was defined as the ratio between the pulse pressure variation and stroke volume variation. Receiver operating characteristic curve analysis was performed to assess the arterial pressure responsiveness after fluid challenge during robot-assisted laparoscopic prostatectomy. Of the 39 patients, 17 were arterial pressure responders and 22 were arterial pressure nonresponders. The mean dynamic Ea before fluid challenge was significantly higher in arterial pressure responders than in arterial pressure nonresponders (0.79 vs 0.61, P < 0.001). In receiver operating characteristic curve analysis, dynamic Ea showed an area under the curve of 0.810. The optimal cut-off value of dynamic Ea for predicting an MAP increase of ≥ 15% after fluid challenge was 0.74. Dynamic Ea can predict an MAP increase ≥ 15% after fluid challenge during robot-assisted laparoscopic prostatectomy. This result suggests that evaluation of arterial pressure responsiveness using dynamic Ea helps to maintain an adequate arterial blood pressure and to improve perioperative outcomes in preload-dependent patients receiving robot-assisted laparoscopic prostatectomy under pneumoperitoneum and in the steep Trendelenburg position.