A survey of current practices, attitudes and demands of anaesthesiologists regarding the depth of anaesthesia monitoring in China.

BACKGROUND: In this study, we aimed to analyse survey data to explore two different hypotheses; and for this purpose, we distributed an online survey to Chinese anaesthesiologists. The hypothetical questions in this survey include: (1) Chinese anaesthesiologists mainly use the depth of anaesthesia (DoA) monitors to prevent intraoperative awareness and (2) the accuracy of these monitors is the most crucial performance factor during the clinical daily practice of Chinese anaesthesiologists. METHODS: We collected and statistically analysed the response of a total of 12,750 anesthesiologists who were invited to participate in an anonymous online survey. The Chinese Society of Anaesthesiologists (CSA) trial group provided the email address of each anaesthesiologist, and the selection of respondents was random from the computerized system. RESULTS: The overall response rate was 32.0% (4037 respondents). Only 9.1% (95% confidence interval, 8.2-10.0%) of the respondents routinely used DoA monitors. Academic respondents (91.5, 90.3-92.7%) most frequently used DoA monitoring to prevent awareness, whereas nonacademic respondents (88.8, 87.4-90.2%) most frequently used DoA monitoring to guide the delivery of anaesthetic agents. In total, the number of respondents who did not use a DoA monitor and whose patients experienced awareness (61.7, 57.8-65.6%) was significantly greater than those who used one or several DoA monitors (51.5, 49.8-53.2%). Overall, the crucial performance factor during DoA monitoring was considered by 61.9% (60.4-63.4%) of the respondents to be accuracy. However, most respondents (95.7, 95.1-96.3%) demanded improvements in the accuracy of the monitors for DoA monitoring. In addition, broad application in patients of all ages (86.3, 85.2-87.4%), analgesia monitoring (80.4, 79.2-81.6%), and all types of anaesthetic agents (75.6, 74.3-76.9%) was reported. In total, 65.0% (63.6-66.5%) of the respondents believed that DoA monitors should be combined with EEG and vital sign monitoring, and 53.7% (52.1-55.2%) believed that advanced DoA monitors should include artificial intelligence. CONCLUSIONS: Academic anaesthesiologists primarily use DoA monitoring to prevent awareness, whereas nonacademic anaesthesiologists use DoA monitoring to guide the delivery of anaesthetics. Anaesthesiologists demand high-accuracy DoA monitors incorporating EEG signals, multiple vital signs, and antinociceptive indicators. DoA monitors with artificial intelligence may represent a new direction for future research on DoA monitoring.

Microsurgery for Vestibular Schwannoma via Retrosigmoid Transmeatal Approach with Intraoperative Monitoring Techniques.

BACKGROUND: Functional preservation of cranial nerves remains an issue in surgical treatment of vestibular schwannoma. AIMS: To explore the functional outcomes of vestibular schwannoma removed by microsurgery via a retrosigmoid transmeatal approach with intraoperative monitoring techniques. STUDY DESIGN: A retrospective cross-sectional study was conducted on a group of patients with vestibular schwannoma operated by microsurgery. METHODS: The outcomes, including the extent of tumor removal, the anatomic positions of the facial nerve, and postoperative Karnofsky performance status score, facial nerve function, and hearing function were reviewed and were statistically compared among tumor sizes (small, medium, and giant) and intraoperative monitoring types [electrophysiological monitoring only (E), electrophysiological monitoring + intraoperative imaging examination (E+I), and electrophysiological monitoring + neuronavigation (E+N)]. RESULTS: A total of 436 patients with VS received microsurgery. The position of the facial nerve was anterior in 85.5% of cases with small vestibular schwannoma. Other position patterns, especially anterior- superior and anterior-inferior, increased in tumors > 2.0 cm. Total resections were performed in all patients with small vestibular schwannoma. A total of 98.1% and 84.8% of patients with medium and giant vestibular schwannoma, respectively, had total resections. More than 90% of patients in all of the 3 monitoring groups had total resections. More than 80% of patients had excellent Karnofsky performance status score regardless of tumor size and monitoring type. After surgery, 100%, 84.4%, and 59.8% of patients with small-, medium-, and giant-sized vestibular schwannoma, respectively, had good facial nerve function. More than 70% of patients in all of the 3 monitoring groups had good facial nerve function postoperatively. The hearing preservation rate was 26.7% and 7.7% in small- and medium-sized vestibular schwannoma, respectively, and was 21.6% and 27.3% in the E group and the E+N group, respectively. The statistical analyses showed that tumor size was significantly associated with the extent of tumor resection, facial nerve localization, complications, postoperative Karnofsky performance status score, facial nerve function, and hearing function (all P ≤ .001). Monitoring type was significantly associated with the extent of resection (P ≤ .001). Additionally, patients in the E+N group had higher total resection rates than those in the E group (P ≤ .001). No cerebrospinal fluid leakage and surgery-related death occurred. CONCLUSION: In vestibular schwannoma microsurgery, tumor size is an important parameter that affects the localization of the facial nerve, the extent of resection, postoperative outcomes and complications. Intraoperative electrophysiological techniques combined with neuronavigation may be helpful to improve the extent of resection.

Intraoperative nerve monitoring in thyroid surgery: analysis of United Kingdom registry of endocrine and thyroid surgery database.

BACKGROUND: Intraoperative nerve monitoring (IONM) is used increasingly in thyroid surgery to prevent recurrent laryngeal nerve (RLN) injury, despite lack of definitive evidence. This study analysed the United Kingdom Registry of Endocrine and Thyroid Surgery (UKRETS) to investigate whether IONM reduced the incidence of RLN injury. METHODS: UKRETS data were extracted on 28 July 2018. Factors related to risk of RLN palsy, such as age, sex, retrosternal goitre, reoperation, use of energy devices, extent of surgery, nodal dissection and IONM, were analysed. Data with missing entries for these risk factors were excluded. Outcomes of patients who had preoperative and postoperative laryngoscopy were analysed. RESULTS: RLN palsy occurred in 4.9 per cent of thyroidectomies. The palsy was temporary in 64.6 per cent and persistent in 35.4 per cent of patients. In multivariable analysis, IONM reduced the risk of RLN palsy (odds ratio (OR) 0.63, 95 per cent confidence interval (CI) 0.54 to 0.74, P < 0.001) and persistent nerve palsy (OR 0.47, 0.37 to 0.61, P < 0.001). Outpatient laryngoscopy was also associated with a reduced incidence of RLN palsy (OR 0.50, 0.37 to 0.67, P < 0.001). Bilateral RLN palsy occurred in 0.3 per cent. Reoperation (OR 12.30, 2.90 to 52.10, P = 0.001) and total thyroidectomy (OR 6.52, 1.50 to 27.80; P = 0.010) were significantly associated with bilateral RLN palsy. CONCLUSION: The use of IONM is associated with a decreased risk of RLN injury in thyroidectomy. These results based on analysis of UKRETS data support the routine use of RLN monitoring in thyroid surgery.

Intraoperative monitoring parameters and postoperative delirium: Results of a prospective cross-sectional trial.

ABSTRACT: Postoperative delirium (PODE) can be associated with severe clinical complications; therefore, preventive measures are important. The objective of this trial was to elucidate whether haemodynamic or electroencephalographic (EEG) monitoring parameters during general anaesthesia or sevoflurane dosage correlate with the incidence of PODE. In addition, sevoflurane dosages and EEG stages during the steady state of anaesthesia were analyzed in patients of different ages.Eighty adult patients undergoing elective abdominal surgery received anaesthesia with sevoflurane and sufentanil according to the clinical routine. Anaesthesiologists were blinded to the EEG. Haemodynamic parameters, EEG parameters, sevoflurane dosage, and occurrence of PODE were analyzed.Thirteen patients (4 out of 33 women, 9 out of 47 men) developed PODE. Patients with PODE had a greater mean arterial pressure (MAP) variance (267.26 (139.40) vs 192.56 (99.64) mmHg2, P = .04), had a longer duration of EEG burst suppression or suppression (27.09 (45.32) vs 5.23 (10.80) minutes, P = .03), and received higher minimum alveolar sevoflurane concentrations (MAC) (1.22 (0.22) vs 1.09 (0.17), P = .03) than patients without PODE. MAC values were associated with wide ranges of EEG index values representing different levels of hypnosis.The results suggest that, in order to prevent PODE, a great variance of MAP, higher doses of sevoflurane, and deep levels of anaesthesia should be avoided. Titrating sevoflurane according to end-tidal gas monitoring and vital signs can lead to unnecessarily deep or light hypnosis. Intraoperative EEG monitoring may help to prevent PODE.

What is the impact of continuous neuromonitoring on the incidence of injury to the recurrent laryngeal nerve during total thyroidectomy?

BACKGROUND: Continuous intraoperative neuromonitoring may facilitate reversal of intraoperative injurious operative maneuvers in comparison with intermittent intraoperative neuromonitoring. The aim of this study was to evaluate the impact of the routine use of continuous intraoperative neuromonitoring on intraoperative injuries to the recurrent laryngeal nerve. METHOD: This study was a prospective case series with retrospective analysis of consecutive patients undergoing total thyroidectomy from August 2013 to August 2019. During this period, intermittent intraoperative neuromonitoring (before Mar 2016) and continuous intraoperative neuromonitoring (after Mar 2016) were used in all patients. RESULTS: We reviewed the outcomes of 603 patients (466 female patients) comprising 236 who underwent intermittent intraoperative neuromonitoring and 367 who underwent continuous intraoperative neuromonitoring. Intraoperative adverse electromyography events (>50% decrease in amplitude between VN1 and VN2) were observed in 87 patients (14.5%) and were less frequent in the continuous intraoperative neuromonitoring group (10.6 vs 20.3%, P = .001). Intraoperative loss of signal (electromyography events with VN2 ≤100µV) were observed in 35 patients (5.8%) without any difference between the 2 groups of patients (5.2 vs 6.8%, P = .415). Postoperative recurrent laryngeal nerve palsies were observed in 36 patients (5.9%) without any difference between the 2 groups of patients (4.9 vs 7.6%, P = .168). CONCLUSION: The routine use of continuous intraoperative neuromonitoring improves the rate of intraoperative adverse electromyography events but does not impact significantly the rates of loss of signal and recurrent laryngeal nerve palsy.

The predictive value of intraoperative transit-time flow measurement parameters for early graft failure in different target territories.

BACKGROUND: Early graft failure can affect the short- and long-term outcomes of patients undergoing coronary bypass grafting surgery (CABG). The aim of our study was to explore the predictive value of transit-time flow measurement (TTFM) parameters for early graft failure (before discharge) after CABG in different coronary territories and calculate the TTFM cut-off values. METHODS: We analyzed a total of 761 grafts (360 patients) that were evaluated by intraoperative TTFM and computed tomography angiography prior to discharge. Logistic model was established to detect the parameters of TTFM to predict early graft failure and receiver operating characteristic curve analysis was used to calculate the cut-off values. RESULTS: The overall early graft failure was 3.5%. The results demonstrated that compared with off-pump CABG, mean graft flow volume was higher (28.0 vs 21.0 mL/min, p = 0.000), but pulse index (PI) (2.3 vs 2.5, p = 0.049) and diastolic flow fraction (DF) (68.0% vs 71.0%, p = 0.001) were lower in on-pump CABGs. DF (73.0% vs 65.5%, p = 0.000) of arterial grafts was higher than that of venous grafts. DF (72.0% vs 62.0%, p = 0.000) in left was higher than that in the right coronary artery territories. The results of multivariate logistic analysis showed that not only in the overall (OR 1.18, 95% CI 1.07-1.30, p = 0.001), but also the left (OR 1.21, 95% CI 1.03-1.41, p = 0.017) and right (OR 1.15, 95% CI 1.03-1.29, p = 0.017) coronary artery target territories, PI was a risk factor for early graft failure and the cut-off value was 3.4, 3.4, and 3.6, respectively. For grafts in left target territories, the results showed that DF (OR 0.94, 95% CI 0.91-0.97, p = 0.000) just in the univariate analysis was a risk factor that affected graft failure. CONCLUSIONS: The overall early graft failure was about 3.5%. High PI value is a risk factor for early graft failure in not only overall grafts but in grafts of different target territories. DF might be more useful for the quality evaluation of grafts in left than in right target territories.

Is there any difference between oral preemptive pregabalin vs. placebo administration on response to EBUS-TBNA under sedation?

Background/aim: The aim of this study is to evaluate the effects of preemptive oral pregabalin on hemodynamic response, anxiety, sedation, and recovery in patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) under sedation with intravenous ketamine-propofol combination. Materials and methods: Sixty patients were included in this study, and patients were randomly divided into two equal groups to receive the placebo (Group 1) versus pregabalin 150 mg (Group 2) one hour prior to EBUS- TBNA procedure. Patients received 0.25 mg kg-1 ketamine and 0.25 mg kg-1 propofol mixture (ketofol) for sedation. Timing of the parameters was defined as follows; T0: in hospital ward before pregabalin or placebo administration, T1: premedication, T2: in operating room, T3: before the procedure, T4: initiation, T5: 3 min after induction, T6: 6 min after induction, T7: 9 min after induction, and T8: 12 min after induction. Hemodynamic parameters, severity of coughing, sedation and anxiety scores, and complications were recorded. The level of satisfaction of the bronchoscopist and the patients were evaluated at the end of the procedure. Results: The heart rate and mean arterial pressure were significantly higher in Group 1 (P = 0.008, P = 0.04). Total doses of anesthetics, recovery time, and desaturation rate were significantly higher in Group 1 (P = 0.014, P = 0.001, P = 0.045). In Group 2, SpO2 level was significantly higher at various time periods (T1; P = 0.025, T4; P =0.043, T6; P = 0.001, T7; P = 0.003, T8; P < 0.001). The severity of coughing was found significantly lower in Group 2 (T4; P = 0.011, T5; P = 0.01, T6; P = 0.02, T7; P = 0.03, T8; P < 0.01). Anxiety scores were significantly lower in Group 2 (P < 0.001). Conclusion: Preemptive oral pregabalin, in addition to sedation with ketamine-propofol combination, was effective in providing limited hemodynamic response, restricted coughing reflex, and lower anxiety during EBUS-TBNA. Besides, with pregabalin usage, decreased anesthetics consumption, lower complication rate, and shorter recovery time might have contributed to safety of the procedure and comfort of the bronchoscopist.

Recurrent Laryngeal Nerve Injury After Thyroid Surgery: An Analysis of 11,370 Patients.

BACKGROUND: Recurrent laryngeal nerve (RLN) injury is a well-known, potentially serious complication of thyroid surgery. We investigated factors associated with RLN injury during thyroid surgery using a multi-institutional data set. MATERIALS AND METHODS: Patients who underwent either lobectomy or total thyroidectomy were abstracted from the American College of Surgeons National Surgical Quality Improvement Program thyroidectomy-specific database (2016-2017). Baseline and operative factors associated with RLN injury ≤30 d of surgery were analyzed using bivariate and multivariate methods. Secondary complications of interest included unplanned reintubation and hypocalcemia. RESULTS: RLN injury occurred in 6.0% (n = 677) of the 11,370 patients included in the study. The RLN injury rate varied significantly based on the primary indication for surgery, from 4.3% in patients undergoing surgery for a single nodule to 9.0% in patients undergoing surgery for differentiated cancer (P < 0.01). RLN injury occurred more often in thyroidectomies than lobectomies (6.9% versus 4.3%, P < 0.01) and in surgeries without intraoperative nerve monitoring (6.5% versus 5.6%, P = 0.01). After multivariate adjustment, RLN injury was independently associated with age ≥65 y [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.3-2.0], total thyroidectomy (OR = 1.4, 95% CI 1.1-1.6), and diagnosis of thyroid malignancy (OR = 2.1, 95% CI = 1.6-2.7) (all P < 0.001) but not intraoperative RLN monitoring (OR = 0.9, 95% CI = 0.7-1.0, P = 0.06). CONCLUSIONS: In this large multi-institutional study, RLN injury ≤30 d of surgery occurred in nearly 6% of thyroid surgeries. This comprehensive analysis of RLN injury can be used to guide informed consent discussions and aid surgeons in identifying candidates who may be at higher risk for injury.

Predictive Value of Intraoperative Doppler Flowmetry for Delayed Graft Function in Kidney Transplantation: A Pilot Study.

BACKGROUND: The delayed graft function (DGF) in kidney transplantation (KT) is a risk factor for long-term poor graft survival. The pathogenesis is multifactorial but mainly related to an ischemia-reperfusion injury. However, the graft hemodynamics have been recently identified as a key aspect for early DGF risk assessment and potential therapeutic intervention. METHODS: A pilot study on 20 single kidney grafts from donor after brain death with intraoperative measurement of graft arterial flowmetry, 30 minutes after reperfusion. Exclusion criteria were grafts with multiple arteries or severe atherosclerosis of the recipient's external iliac artery. RESULTS: KT recipients with DGF (n = 4, 20%) were homogenous with controls (n = 16) in terms of cold ischemia time, donor age, recipients' hemodynamic parameters, renal artery, and recipients' external iliac artery diameters. Nonetheless, at transplant, the kidney grafts that developed DGF were characterized by a significantly higher renal artery resistive index (DGF vs no-DGF 0.96 ± 0.04 vs 0.77 ± 0.13, P = .02), as well as lower flow extraction rate (24.8% ± 11.8 vs 59.2% ± 21.1, P < .01). CONCLUSIONS: Intraoperative arterial graft flowmetry seems to be an effective tool to identify grafts at high risk of DGF.

Development of a prediction model for hypotension after induction of anesthesia using machine learning.

Arterial hypotension during the early phase of anesthesia can lead to adverse outcomes such as a prolonged postoperative stay or even death. Predicting hypotension during anesthesia induction is complicated by its diverse causes. We investigated the feasibility of developing a machine-learning model to predict postinduction hypotension. Naïve Bayes, logistic regression, random forest, and artificial neural network models were trained to predict postinduction hypotension, occurring between tracheal intubation and incision, using data for the period from between the start of anesthesia induction and immediately before tracheal intubation obtained from an anesthesia monitor, a drug administration infusion pump, an anesthesia machine, and from patients' demographics, together with preexisting disease information from electronic health records. Among 222 patients, 126 developed postinduction hypotension. The random-forest model showed the best performance, with an area under the receiver operating characteristic curve of 0.842 (95% confidence interval [CI]: 0.736-0.948). This was higher than that for the Naïve Bayes (0.778; 95% CI: 0.65-0.898), logistic regression (0.756; 95% CI: 0.630-0.881), and artificial-neural-network (0.760; 95% CI: 0.640-0.880) models. The most important features affecting the accuracy of machine-learning prediction were a patient's lowest systolic blood pressure, lowest mean blood pressure, and mean systolic blood pressure before tracheal intubation. We found that machine-learning models using data obtained from various anesthesia machines between the start of anesthesia induction and immediately before tracheal intubation can predict hypotension occurring during the period between tracheal intubation and incision.

Influence of common clinical variables on intraoperative parathyroid hormone monitoring during surgery for primary hyperparathyroidism.

BACKGROUND: Intraoperative monitoring of parathyroid hormone (IOPTH) is a reliable method of predicting the cure of primary hyperparathyroidism (PHPT). The aim of this study is to assess whether common clinical variables (CCV) frequently encountered in patients with PHPT may affect the magnitude of PTH drop or the likelihood of patients meeting the intraoperative cure criterion. DESIGN: Patients who were surgically cured from PHPT caused by single gland disease (SGD) and had full IOPTH protocol (4 measurements) were stratified according to age, gland weight, renal function, vitamin D status and severity of hypercalcemia. The percentage of IOPTH drop and the frequency of patients who had true positive IOPTH test results were compared among groups. RESULTS: 762 patients had surgery for PHPT, of whom 746 were (98%) cured. Of these 746 patients, 511 who had SGD and a full IOPTH protocol were included in this study. The median IOPTH drop was significantly higher among younger patients, those with severe hypercalcaemia at 5, 10, 15 min after gland excision, giant glands (at 5-min only), patients with vitamin D deficiency (at 10, 15 min), and those with normal renal function (at 15 min only). The likelihood of the patients meeting the intraoperative cure criterion was not significantly affected among the groups except in patients with mild hypercalcaemia, who were significantly less likely to have 50% IOPTH drop than those with severe hypercalcaemia at all time points. The frequency of mildly hypercalcaemic patients who met cure criterion was significantly improved by extending measurement to 15 min. CONCLUSIONS: IOPTH monitoring has the ability to mitigate the variability of IOPTH kinetics associated with most clinical variables. Mildly hypercalcemic patients in particular may benefit from waiting for 15-min measurement before any surgical decision is made.

Increased prevalence of neural monitoring during thyroidectomy: Global surgical survey.

OBJECTIVE: To investigate intraoperative nerve monitoring (IONM) use among thyroid surgeons. METHODS: A 25-question survey was used to assess attitudes regarding IONM use. Surveys were sent to surgeons registered to the American Academy of Otolaryngology-Head and Neck Surgery, International Association of Endocrine Surgeons, and American Head and Neck Society. RESULTS: Among 1,015 respondents, 83% reported using IONM (65.1% always using IONM and 18.1% reporting selective use). For selective users, a majority reported using IONM for reoperative cases (95.1%) and in cases with preoperative vocal cord paralysis (59.8%). When comparing location, there was a significant difference in IONM implementation (P < 0.001), with 70.4% of North American responders using it ubiquitously compared to 27.4% of non-North American responders. Preoperative laryngeal exam was performed more universally by North American surgeons and more selectively by non-North American surgeons (P < 0.001). Other attitudes toward their implementation and the postoperative laryngeal exam were similar. Surgeons ≤45 years of age and those with ≤15 years of practice used IONM more than their peers (P < 0.001). Thyroid surgery volume, fellowship training, and type of practice had no bearing on IONM use. CONCLUSION: The prevalence of IONM in thyroid and parathyroid surgeries has increased significantly over the past decade, with 83% of surgeons using IONM in some or all cases. Although IONM use may be more ubiquitous in North America, attitudes toward its implementation and pre- and postoperative laryngeal exams are fairly uniform. IONM use is more prevalent among younger surgeons, whereas its use has no correlation with thyroid surgery volume or type of practice. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1097-1104, 2020.

Validation of electrical velocimetry in resuscitation of patients undergoing liver transplantation. Observational study.

Major hemodynamic changes are frequently noted during liver transplantation (LT). We evaluated the performance of electrical velocimetry (EV) as compared to that of TEE in SV optimization during liver transplantation. This was an observational study in 32 patients undergoing LT. We compared SV values measured simultaneously by EV (SVEV) and TEE (SVTEE) at baseline 30 min after induction, at the end of dissection phase, 30 min after anhepatic phase, 30 min after reperfusion. We also evaluated the reliability of EV to track changes In SV before and after 49 fluid challenges. Finally, the SV variation (SVV) and pulse pressure variation (PPV) were tested as predictors for volume responsiveness, defined as an increase in SV ≥ 10% after 250 ml of colloid. For 112 paired SV data, the overall correlation was 0.76 and bias (limits of agreement) 0.3 (- 29 to 29) ml percentage error 62%. The EV was able to track changes in SV with a concordance rate of 97%, and a sensitivity and specificity of 93% to detect a positive fluid challenge. The AUC values (with 95% confidence intervals) for SVV and PPV were 0.68 (0.52-0.83) and 0.72 (0.57-0.86), respectively, indicating low predictive capacity in these setting. The absolute values of SV derived from EV did not agree with SV derived from TEE. However, EV was able to track the direction of changes in SV during hemodynamic management of patients undergoing liver transplantation.Clinical trial registration: Clinicaltrials.gov Identifier: NCT03228329 prospectively Registered on 13-July-2017.

Multimodal Intraoperative Spinal Cord Monitoring during Spinal Deformity Surgery: Efficacy, Diagnostic Characteristics, and Algorithm Development.

OBJECTIVE: This study aims to present the diagnostic characteristics of multimodal intraoperative monitoring (IOM) in spinal deformity surgery and to define and categorise the neuromonitoring events, as well as propose an algorithm of action. MATERIALS AND METHODS: We reviewed 1,155 consecutive patients (807 female, 348 male) who underwent deformity correction using standardised perioperative care, cortical/cervical somatosensory evoked potentials (SSEPs), and upper/lower limb transcranial electrical motor evoked potential (MEPs) by a single surgeon. The mean age at surgery was 13.8 years (range 10-23.3). We categorised IOM events as true, transient true, and false positive or negative. Diagnostic performance criteria were calculated. RESULTS: The most common diagnosis was adolescent idiopathic scoliosis in 717 (62%) patients. We identified 3 true positive monitoring events occurring in 2 patients (0.17%), 8 transient true positive (0.69%), and 8 transient false positive events (0.69%). There were no false negative events and no patient had postoperative neurological complications. The multimodal IOM technique had a sensitivity of 100%, specificity of 99.3%, positive predictive value of 55.6%, and negative predictive value of 100%. Sensitivity was 100% for MEPs and multimodal monitoring compared to 20% for cortical or cervical SSEPs. The frequency of true or transient true positive events was higher (p = 0.07) in Scheuermann's kyphosis (3/91 patients, 3.3%) compared to adolescent idiopathic scoliosis (6/717 patients, 0.84%). CONCLUSION: Multimodal IOM is highly sensitive and specific for spinal cord injury. This technique is reliable for the assessment of the condition of the spinal cord during major deformity surgery. We propose an algorithm of intraoperative action to allow close cooperation between the surgical, anaesthetic, and neurophysiology teams and to prevent neurological deficits.

The utility of intraoperative navigation of the temporal bone for otolaryngology resident training.

OBJECTIVES: To determine whether image guidance improves dissection quality among residents in the temporal bone lab and to gauge their reactions to its use. METHODS: Prospective cohort study of nine otolaryngology residents who dissected cadaveric temporal bones with and without image guidance in the temporal bone laboratory. Quality of dissection was measured with the Welling scale. A survey was administered assessing their interactions with the navigation system. RESULTS: There was no significant difference in quality of dissection for the majority of structures or number of major errors with use of image guidance. Dissection quality of the tegmen (4.67 vs. 5.67, P = .034) and sinodural angle (0.83 vs. 1.56, P = .005) was superior in the non-navigation specimens. The majority of residents reported increased confidence with locating several critical anatomic structures and found the system intuitive to use. Nearly all thought it would be helpful in revision cases or for aural atresia. CONCLUSION: Image guidance did not improve quality of temporal bone dissection or number of major errors in this cohort of residents, but the majority found it intuitive and increased confidence in finding several structures. Navigation systems may play an important adjunctive role in resident education and further work is required to determine its optimal use. LEVEL OF EVIDENCE: NA Laryngoscope, 130:E368-E371, 2020.

Confirmation of Parathyroid Tissue: Are Surgeons Aware of New and Novel Techniques?

BACKGROUND: Ex vivo aspiration of parathyroid glands for the measurement of intraoperative parathyroid hormone (IOPTH) levels is a rapid point-of-care method to confirm parathyroid tissue during parathyroidectomy and an alternative to frozen section (FS). This study sought to determine the awareness and utilization of this technique among endocrine surgeons. MATERIALS AND METHODS: A de-identified 12-question survey regarding techniques for intraoperative identification/confirmation of parathyroid tissue and the use of IOPTH monitoring was distributed to all 608 members of the American Association of Endocrine Surgeons. RESULTS: Among the 182 (30%) respondents, FS was the most common primary technique utilized by 115 (63%) respondents to confirm parathyroid tissue; only 12 (7%) utilized ex vivo aspiration, although 78 (42%) were familiar with the technique. Availability and familiarity were the principal reasons for use of the primary technique; the most common barrier was time. Serum IOPTH monitoring was routinely used by 124 (74%). Of respondents who utilized FS, serum IOPTH monitoring was routinely used by 75% (86/115), including 71% (45/63) who reported time as a barrier to FS. Of these 45, only 15 (33%) were familiar with ex vivo parathyroid aspiration. Only 48% of surgeons knew how PTH samples were charged. CONCLUSIONS: FS was the most common method of identification/confirmation of parathyroid tissue. Although most respondents routinely performed IOPTH monitoring, relatively few utilized ex vivo aspiration as a technique for parathyroid identification and less than 50% were familiar with this technique. Broader dissemination about novel techniques such as ex vivo aspiration and cost awareness are recommended.

Risk Stratification for Postoperative Acute Kidney Injury in Major Noncardiac Surgery Using Preoperative and Intraoperative Data.

Importance: Acute kidney injury (AKI) is one of the most common complications after noncardiac surgery. Yet current postoperative AKI risk stratification models have substantial limitations, such as limited use of perioperative data. Objective: To examine whether adding preoperative and intraoperative data is associated with improved prediction of noncardiac postoperative AKI. Design, Setting, and Participants: A prognostic study using logistic regression with elastic net selection, gradient boosting machine (GBM), and random forest approaches was conducted at 4 tertiary academic hospitals in the United States. A total of 42 615 hospitalized adults with serum creatinine measurements who underwent major noncardiac surgery between January 1, 2014, and April 30, 2018, were included in the study. Serum creatinine measurements from 365 days before and 7 days after surgery were used in this study. Main Outcomes and Measures: Postoperative AKI (defined by the Kidney Disease Improving Global Outcomes within 7 days after surgery) was the primary outcome. The area under the receiver operating characteristic curve (AUC) was used to assess discrimination. Results: Among 42 615 patients who underwent noncardiac surgery, the mean (SD) age was 57.9 (15.7) years, 23 943 (56.2%) were women, 27 857 (65.4%) were white, and the most frequent surgery types were orthopedic (15 718 [36.9%]), general (8808 [20.7%]), and neurologic (6564 [15.4%]). The rate of postoperative AKI was 10.1% (n = 4318). The progressive addition of clinical data improved model performance across all modeling approaches, with GBM providing the highest discrimination by AUC. In GBM models, the AUC increased from 0.712 (95% CI, 0.694-0.731) using prehospitalization variables to 0.804 (95% CI, 0.788-0.819) using preoperative variables (inclusive of prehospitalization variables) (P < .001 for AUC comparison). The AUC further increased to 0.817 (95% CI, 0.802-0.832) when adding intraoperative variables (P < .001 for comparison vs model using preoperative variables). However, the statistically significant improvements in discrimination did not appear to be clinically significant. In particular, the AKI rate among patients classified as high risk improved from 29.1% to 30.0%, a net of 15 patients were appropriately reclassified as high risk, and an additional 15 patients were appropriately reclassified as low risk. Conclusions and Relevance: The findings of the study suggest that electronic health record data may be used to accurately stratify patients at risk of perioperative AKI, but the modest improvements from adding intraoperative data should be weighed against challenges in using intraoperative data.

Delay in detection and treatment of perioperative anemia in hip fracture surgery and its impact on postoperative outcomes.

BACKGROUND: Elderly patients with hip fractures are at high risk for perioperative anemia as a result of fracture- and surgery-related blood loss. The detection of anemia is dependent on intermittent blood samples and therefore might be delayed, potentially leading to a significant delay in transfusion. This study aimed to investigate the possible delay in perioperative anemia detection, accumulated perioperative anemia-associated burden, peripheral perfusion, and their association with patient outcomes in elderly patients with hip fracture. METHODS: Elderly patients with acute hip fracture scheduled for surgery were enrolled in this prospective study from August 2016 to December 2016. All patients were monitored continuously for hemoglobin concentration (SpHb) and perfusion index (PI) with the Radical-7® Pulse CO-Oximeter® and Rainbow® R1 Adhesive Multi-parameter Sensors (Masimo Corp., Irvine, CA, US) from 12 h presurgery to 24 h postsurgery. RESULTS: Fifty-one patients were enrolled, and 41 were included in the final analyses. Mean delay in the detection of low Hb (<10 g/dL) using intermittent blood samples, when compared with SpHb, was 1.07 h (standard deviation, ±2.84 h). Median perioperative cumulated time with low SpHb (<10 g/dL for at least one min) was 25 min (interquartile range [IQR]: 21-690). There was a significant association between perioperative time with low SpHb and the occurrence of postoperative delirium (median cumulated time with low SpHb: 162 min in patients with delirium vs 22 min in patients without delirium, P = 0.034) and a nonsignificant trend for an association between perioperative time with low SpHb and 90-day mortality or medical complications (median cumulated time with low SpHb: 119 min for patients with mortality or severe complication vs 22 min for patients without mortality or severe complication, P = 0.104). PI values during the perioperative period were not significantly associated with patient outcomes. Cumulated time with low PI (<0.5) preoperatively (but not perioperatively) was significantly associated with the occurrence of postoperative delirium (P = 0.047). CONCLUSIONS: This study showed a delay in transfusion threshold detection, and the presence of significant associations between low SpHb or time with low SpHb and postoperative outcomes.

Assessing the Association Between Blood Loss and Postoperative Hemoglobin After Cesarean Delivery: A Prospective Study of 4 Blood Loss Measurement Modalities.

BACKGROUND: Visual estimation and gravimetric methods are commonly used to quantify the volume of blood loss during cesarean delivery (CD). However, the correlation between blood loss and post-CD hemoglobin (Hb) is poorly studied, and it is unclear whether the correlation varies according to how blood loss is measured. METHODS: After obtaining Institutional Review Board approval, we performed a prospective study of 61 women undergoing CD to assess the relations between post-CD Hb and blood loss measured using 4 modalities: gravimetric blood loss measurement (gBL), visual blood loss estimation by a blinded obstetrician (oBL) and anesthesiologist (aBL), and the Triton System (tBL). Hb was measured preoperatively and within 10 minutes after CD. gBL was quantified as blood volume in a suction canister in addition to the weight of blood-soaked sponges. tBL was measured with the Triton System by photographing blood-soaked sponges and suction canister contents. To assess the relation between blood loss and post-CD Hb, we performed correlation analyses and compared the magnitude of the correlations across the 4 measurement modalities using William t test. A Bonferroni correction was set to identify a statistically significant correlation (P < .0125) and statistically significant differences between correlation coefficients (P < .008). RESULTS: The mean (standard deviation) preoperative Hb was 12 (1.1) g/dL and post-CD Hb was 11.3 (1.0) g/dL. Median (interquartile range) values for gBL, oBL, aBL, and tBL were 672 mL (266-970), 700 mL (600-800), 750 mL (600-1000), and 496 mL (374-729), respectively. A statistically significant but weak correlation was observed between tBL and post-CD Hb (r = -0.33; P = .01). No statistically significant correlations were observed among aBL (r = -0.25; P = .06), oBL (r = -0.2; P = .13), and gBL (r = -0.3; P = .03) with post-CD Hb. We did not detect any significant differences between any 2 correlation coefficients across the 4 modalities. CONCLUSIONS: Given that we observed only weak correlations between each modality with post-CD Hb and no significant differences in the magnitude of the correlations across the 4 modalities, there may be limited clinical utility in estimating post-CD Hb from blood loss values measured with any of the 4 modalities.