Comparison of total intravenous with inhalational anesthesia in terms of postoperative delirium and complications in older patients: a nationwide population-based study.

PURPOSE: Postoperative delirium incidences are increasing in older adults. A Cochrane Review found no significant difference in the incidence of postoperative delirium between total intravenous anesthesia (TIVA) and inhalational anesthesia (IA). This study evaluated the differences in postoperative delirium and morbidity between patients who underwent either TIVA or IA. METHODS: A nationwide Japanese inpatient database was used to retrospectively compare differences in postoperative delirium and composite morbidity between patients older than 65 years, who underwent general anesthesia (TIVA or IA). The primary outcome was postoperative delirium. The secondary outcomes were: morbidity incidence, length of hospital stay, and mortality. A 1:3 propensity score analysis of patients who underwent all surgical procedures was conducted according to covariates, to calculate odds ratios and their 95% confidence intervals (CIs). Sensitivity analyses were conducted using an instrumental variable analysis of the proportion of TIVA by hospital scale, stabilized inverse probability of treatment weighting analyses, limiting the definitions of postoperative delirium, and subgroup analysis. RESULTS: Of 738,600 patients, 149,540 received TIVA and 589,060 received IA. After 1:3 propensity score matching, the adjusted odds ratios for postoperative delirium and composite morbidity were 0.93 (95% CI 0.91-0.95) and 0.94 (95% CI 0.90-0.97), respectively, for TIVA concerning IA. There were no differences in the length of the intensive care unit and hospital stay, or hospital mortality. The findings were consistent with the sensitivity analyses. CONCLUSIONS: This study demonstrated that TIVA was related to a slightly decreased postoperative delirium and incidence of morbidity compared to IA.

The usefulness of Smart Pilot View for fast recovery from desflurane general anesthesia.

INTRODUCTION: Smart Pilot View (SPV) (Dräger Medical) provide information about the estimated drug effect of anesthetic drugs. We conducted a prospective randomized trial to evaluated the recovery time in SPV-guided general anesthesia compared with usual practice in patients with desflurane general anesthesia. METHOD: Thirty-four American Society of Anesthesiologist's physical status I-II patients scheduled for elective surgery under general anesthesia were enrolled in the study. The patients were allocated to one of the following two groups: the Smart Pilot View group (group SPV) or the control group (group C). General anesthesia was induced by propofol and maintained by desflurane end-tidal concentration of 4.2%. During the procedure, desflurane concentration was adjusted to maintain BIS values between 40 and 60 and above MAC 90. In group SPV, desflurane concentration and infusion rate of remifentanil were decreased to achieve MAC 90 about 10 min before the end of the procedure. In group C, the desflurane concentration and infusion rate of remifentanil were maintained unchanged until the end of the procedure. RESULTS: Fifteen patients were enrolled in group C, and seventeen of these were enrolled in group SPV. The time taken for the opening of the patient's eyes was 292 ± 53 s in group C and 218 ± 44 s in group SPV. The time taken for recovery of orientation was 451 ± 100 s in group C and 316 ± 57 s in group SPV. Both times were significantly faster in the group SPV. CONCLUSION: Smart Pilot View guided anesthesia enabled faster recovery from desflurane general anesthesia.

Perseus A500 enables faster recovery from desflurane general anesthesia.

PURPOSE: The Dräger Perseus A500 (Perseus) anesthetic workstation has been designed with a lower internal volume. We evaluated the recovery time following general anesthesia using the Perseus workstation compared with that using the conventional Dräger Fabius Plus workstation. METHODS: Following approval by our institutional research ethics committee, 50 patients receiving elective surgery under general anesthesia were enrolled in the study. Written informed consent was obtained from each patient. The patients were divided into the Perseus group and a control group. The Perseus anesthesia workstation was used for the Perseus group, and the Fabius Plus was used for the control group. General anesthesia was maintained with a 4.2% end-tidal concentration of desflurane, remifentanil, fentanyl, and regional anesthesia. After the surgical procedure, the administration of desflurane was discontinued. The inspiratory and expiratory desflurane concentration, time taken for patients to open their eyes, and the time taken to extubate the trachea after discontinuation of anesthetics were recorded. RESULTS: The inspiratory and expiratory desflurane concentration after the administration of desflurane was discontinued was lower in the Perseus group. Moreover, the time taken for patients to open their eyes was statistically significantly quicker in the Perseus group when compared with the control group: 284 ± 60 vs 325 ± 43 s, respectively. The time taken for extubation was also statistically significantly quicker in the Perseus group when compared with the control group: 350 ± 67 vs 388 ± 62 s, respectively. CONCLUSIONS: We demonstrate in this study that Perseus enables the faster wash-out of anesthetics and faster recovery of patients after general anesthesia.

Development and validation of a machine learning model to predict postoperative delirium using a nationwide database: A retrospective, observational study.

STUDY OBJECTIVE: Postoperative delirium is a neuropsychological syndrome that typically occurs in surgical patients. Its onset can lead to prolonged hospitalization as well as increased morbidity and mortality. Therefore, it is important to promptly identify its signs. This study aimed to develop and validate a machine learning predictive model for postoperative delirium using extensive population data. DESIGN: Retrospective observational study. SETTING: Japanese Diagnosis Procedure Combination inpatient data. Data were used for internal (2016.4-2018.12) and temporal validation (2019.01-2019.10). PATIENTS: Patients aged ≥65 years who underwent general anesthesia for surgical procedure. MEASUREMENTS: The primary outcome was postoperative delirium, which was defined as a condition requiring newly prescribed antipsychotic drugs or assignment of the corresponding insurance claim code after the date of surgery. We trained and tuned the optimal machine-learning model through 10-fold cross-validation using the selected optimal area under the receiver operating characteristic curve (AUC) value. In the temporal validation, we measured the performance of our model. MAIN RESULTS: The analysis included 557,990 patients. The light-gradient boosting machine models showed a higher AUC value (0.826 [95% confidence interval (CI): 0.822-0.829]) than the other models. Regarding performance, the model had a recall value of 0.124 (95% CI: 0.119-0.129) and precision value of 0.659 (95% CI: 0.641-0.677]). This performance was sustained in the temporal validation (AUC, 0.815 [95% CI: 0.811-0.818]). At a sensitivity of 0.80, the model achieved a specificity of 0.672 (95% CI: 0.670-0.674]), a negative predictive value of 0.975 (95% CI: 0.974-0.975), and a positive predictive value of 0.176 (95% CI: 0.176-0.179). CONCLUSIONS: Using extensive Diagnostic Procedure Combination data, we successfully created and validated a machine learning model for predicting postoperative delirium. This model may facilitate prediction of postoperative delirium.

Preoperative echocardiography predictive analytics for postinduction hypotension prediction.

PURPOSE: Hypotension is a risk factor for adverse perioperative outcomes. Preoperative transthoracic echocardiography has been extended for preoperative risk assessment before noncardiac surgery. This study aimed to develop a machine learning model to predict postinduction hypotension risk using preoperative echocardiographic data and compared it with conventional statistic models. We also aimed to identify preoperative echocardiographic factors that cause postinduction hypotension. METHODS: In this retrospective observational study, we extracted data from electronic health records of patients aged >18 years who underwent general anesthesia at a single tertiary care center between April 2014 and September 2019. Multiple supervised machine learning classification techniques were used, with postinduction hypotension (mean arterial pressure <55 mmHg from intubation to the start of the procedure) as the primary outcome and 95 transthoracic echocardiography measurements as factors influencing the primary outcome. Based on the mean cross-validation performance, we used 10-fold cross-validation with the training set (70%) to select the optimal hyperparameters and architecture, assessed ten times using a separate test set (30%). RESULTS: Of 1,956 patients, 670 (34%) had postinduction hypotension. The area under the receiver operating characteristic curve using the deep neural network was 0.72 (95% confidence interval (CI) = 0.67-0.76), gradient boosting machine was 0.54 (95% CI = 0.51-0.59), linear discriminant analysis was 0.56 (95% CI = 0.51-0.61), and logistic regression was 0.56 (95% CI = 0.51-0.61). Variables of high importance included the ascending aorta diameter, transmitral flow A wave, heart rate, pulmonary venous flow S wave, tricuspid regurgitation pressure gradient, inferior vena cava expiratory diameter, fractional shortening, left ventricular mass index, and end-systolic volume. CONCLUSION: We have created developing models that can predict postinduction hypotension using preoperative echocardiographic data, thereby demonstrating the feasibility of using machine learning models of preoperative echocardiographic data for produce higher accuracy than the conventional model.

Comparing the effects of peripheral nerve block and general anesthesia with general anesthesia alone on postoperative delirium and complications in elderly patients: a retrospective cohort study using a nationwide database.

INTRODUCTION: The difference between the effects of peripheral nerve block (PNB) with general anesthesia (GA) and GA alone on the patients' postoperative clinical outcomes remains unknown. We assessed whether there is a difference in postoperative delirium and composite morbidity between patients receiving GA with PNB and GA alone using a national clinical database in Japan. METHODS: We compared the outcomes of patients receiving GA with PNB and GA alone from April 2016 to October 2019. The primary outcome was postoperative delirium, defined as a status requiring newly prescribed antipsychotic drugs or that given the code of a reimbursable disease after the surgery date. The secondary outcome was morbidity incidence as the occurrence of at least one of any of the following life-threatening complications. We conducted propensity score-matched analyses using covariates for patients who underwent any surgical procedure. We used instrumental variables and restricted the definition of postoperative delirium and subgroup for sensitivity analyses. RESULTS: Of 653,759 patients, 90,358 received GA-PNB and 563,401 received only GA. After 1:4 propensity score matching, 89,754 patients were included in the GA-PNB and 359,015 in the GA. The adjusted ORs for postoperative delirium and composite morbidity were 0.96 (95% CIs 0.94 to 0.99; p<0.01), 0.80 (95% CIs 0.76 to 0.83; p<0.001), respectively, for the GA-PNB concerning the GA. For sensitivity analyses, findings were also consistent with instrumental variables and subgroup analyses. DISCUSSION: This retrospective, nationwide cohort study demonstrated that GA-PNB was associated with a small reduction in the likelihood of postoperative delirium and a moderate reduction in the likelihood of composite morbidity.

Anesthetic management of a patient with narcolepsy.

We report the anesthetic management of a narcoleptic patient performed using sevoflurane-remifentanil with bispectral index (BIS) monitoring. A 22-year-old man, who was diagnosed with narcolepsy at the age of 17, requested endoscopic sinus surgery, under general anesthesia, for chronic allergic rhinitis. On the morning of the day of operation, he took his daily dose of modafinil, used to control narcolepsy. Anesthesia was induced by 5% sevoflurane and maintained with sevoflurane and continuous infusion of remifentanil and 60% oxygen in conjunction with BIS monitoring. BIS values were between 47 and 58. Duration of surgery was 150 min. After surgery, the patient emerged from anesthesia within 10 min and was extubated. His recovery was uneventful. We found the use of BIS monitoring for titrating sevoflurane concentration in a narcoleptic patient is useful for preventing not only oversedation but also intraoperative awareness caused by the preoperative medication.

Skin temperature changes after ultrasound-guided supra-inguinal fascia iliaca block: a prospective observational study.

PURPOSE: Ultrasound-guided supra-inguinal fascia iliaca block (SFIB) is widely used as regional anesthesia of the hip and thigh. It is difficult to judge the blocking effect and the spreading local anesthesia. We hypothesize that the effect and spread of the block could be proven objectively by a rise in the temperature. In this prospective observational study, the broad regional rise in skin temperature of twenty patients who were scheduled for hip surgery was measured using an infrared thermographic camera at multiple intervals following ultrasound-guided SFIB. METHODS: Infrared thermographic imaging of skin temperature at the femoral, obturator, and lateral femoral cutaneous nerve sites was performed before and at 5-min intervals after ultrasound-guided SFIB for up to 15-min post-injection. The primary outcomes are skin surface temperature. Sensory block was assessed immediately after the final infrared thermographic image acquisition using the cold test. RESULTS: Compared to pre-injection baseline, temperature increased by 1.2 °C [95% confidence interval (CI) 0.4-2.0 °C] after 5 min, 1.2 °C (95% CI 0.4-2.0 °C) after 10 min, and 0.9 °C (95% CI 0.4-2.1°C) after 15 min. The cold test response was reduced in all cases at the femoral and lateral femoral cutaneous nerve sites and in 13 cases at the obturator nerve site. The sensitivity and specificity of the temperature increase to cold loss were 96% and 63%, respectively when we defined >0°C as the clinical threshold. CONCLUSIONS: Successful SFIB significantly enhanced skin temperature at the hip and thigh in all cases, suggesting that infrared surface thermography can be used as an objective assessment tool for adequate analgesia. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry ( UMIN 000037866 ). Registered 31 August 2019.

Inflationary noninvasive blood pressure measurement reduces the incidence of subcutaneous hemorrhage.

OBJECTIVE: We verified the hypothesis that in noninvasive blood pressure (NIBP) measurement, inflationary NIBP measurement using the new type of cuff (YP-71xT series, Nihon Koden, Tokyo, Japan) might be associated with a reduced risk of subcutaneous hemorrhage. METHODS: The study involved 30 healthy volunteers (15 males and 15 females). The blood pressure was measured by deflationary NIBP measurement + conventional cuff (control group), deflationary NIBP measurement + cuff (YP-71xT series) (deflationary measurement group), or inflationary NIBP measurement + cuff (YP-71xT series) (inflationary measurement group). NIBP measurement was performed five times in a row, then the presence or of subcutaneous hemorrhage was evaluated. The three different methods were used as cross-over design at 1-week interval for each subject so that all three methods were used for all the subjects. RESULTS: The measurement time was significantly shorter in the inflationary measurement group than other groups. The incidence of subcutaneous hemorrhage significantly was lower in the inflationary measurement group (3%) than in control group (53%) (P < 0.001) and the deflationary measurement group (37%) (P = 0.002). CONCLUSION: This study revealed that inflationary NIBP measurement was associated with a dramatically reduced incidence of subcutaneous hemorrhage. Synergistic effect of the newly designed cuff, short measurement time, and low inflation pressure may allow the risk of subcutaneous hemorrhage.

Use of ultrasound for spinal anesthesia in a super morbidly obese patient.

We report the application of ultrasound prescans for spinal anesthesia to morbid obesity patient. A 38-year-old woman with a body mass index (BMI) of 50 (weight: 110 kg; height: 148 cm) was scheduled to undergo pilonidal cyst resection at the bottom of the tailbone. Spinal anesthesia was selected for the procedure, because the patient's position during the surgery was prone and the patient had morbid obesity. To determine the spinal needle insertion point and the distance between the skin and dura, we planned to use ultrasound. The transverse view of the patient's lumbar spine showed the posterior dura, transverse process, and posterior vertebral body below the thick fat tissue. At this point, spinal anesthesia was successfully performed. Pre-insertion ultrasound guidance for spinal anesthesia was useful in this morbidly obese patient with a BMI of 50.