The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: clinical signs, severity, and therapeutic agents.

BACKGROUND: Diagnosis of perioperative anaphylaxis is difficult because of its non-specific and variable signs and symptoms. Therapeutic agents used to treat anaphylaxis and anaesthesiologist responses also vary depending on the case, which might affect outcomes; however, only a few studies have focused on these factors. METHODS: This prospective study of perioperative anaphylaxis, a part of the Japanese Epidemiologic Study for Perioperative Anaphylaxis, investigated the clinical signs, its severity, therapeutic drugs, epinephrine administration, and anaesthesiologist responses in cases of perioperative anaphylaxis to assess trends and variability. Shock index was used to assess severity of cardiovascular collapse. RESULTS: In 43 patients analysed in this study, cardiovascular signs (88.4%) were the most frequent, followed by skin (81.4%) and respiratory signs (60.5%). The presence of signs increased during the clinical course. The median time from the first signs to diagnosis of anaphylaxis was 10 (5.0-17.8) min. The rates of epinephrine use were 30.2% (unused), 48.8% (i.v.), and 20.9% (i.m.). The median time from diagnosis of anaphylaxis to epinephrine administration was 7 (inter-quartile range: 1.5-8.0) min. Antihistamines and corticosteroids were each used in 69.8% of cases. The worst shock index was higher in patients who received i.v. epinephrine (2.77 [0.90] mean [standard deviation]) than in both no epinephrine use cases (1.35 [0.41]) and i.m. epinephrine cases (1.89 [0.77] (P<0.001]). CONCLUSIONS: The clinical signs and treatments of perioperative anaphylaxis are variable, and the choice regarding epinephrine administration is based on symptom severity. CLINICAL TRIAL REGISTRATION: UMIN000035350.

Ninety-day mortality of extremely elderly patients undergoing hip fracture surgery and its association with preoperative cardiac function: a single-center retrospective study.

PURPOSE: We investigated the 90-day mortality rate in elderly patients who underwent hip fracture surgery and the association of preoperative cardiac function with mortality. METHODS: We retrospectively enrolled 133 consecutive patients aged 80 years or older who underwent hip fracture surgery. We obtained information for patient sex, age, comorbidities, medications, anesthesia method, left ventricular systolic and diastolic functions assessed by echocardiography, and preoperative brain natriuretic peptide (BNP) levels. Multivariate logistic regression analysis was performed. RESULTS: The 90-day mortality rate in patients with a mean age of 88.9 years was 7.5% (10/133). More than half of the patients had diastolic dysfunction of the left ventricle. There were no significant differences in preoperative cardiac systolic and diastolic functions between the mortality group and non-mortality group. The preoperative BNP level in the mortality group was significantly higher than that in the non-mortality group (p = 0.038). Preoperative BNP level was not an independent risk factor for 90-day mortality (p = 0.081) in the primary multivariate logistic regression analysis but was an independent risk factor (p = 0.039) with an odds ratio of 1.004 (95% CI 1.000-1.008) in the sensitivity analysis with different explanatory variables. CONCLUSION: The 90-day mortality rate in patients over 80 years old after hip fracture surgery was 7.5%. There were no significant differences in preoperative cardiac function assessed by echocardiography between the mortality and non-mortality groups. Our results suggest that there is no association or only a weak association of high BNP level with 90-day mortality in this age population.

Effects of anesthetics on nociceptive sensory evoked potentials by intraepidermal noxious electrical stimulation of A-δ fibers.

PURPOSE: Generation of nociceptive sensory evoked potentials (NEPs) by selective stimulation of nociceptive intraepidermal nerve fibers is a simple technique which could be used as intraoperative nociception monitor. We evaluated the effects of remifentanil, propofol and sevoflurane on NEPs by this technique. METHODS: Patients undergoing general anesthesia were assigned to groups in two studies. A-δ fiber selective NEPs were recorded. Study 1: NEPs were recorded at control, under anesthetics administration: remifentanil at an effect-site concentration (Ce) of 1.0 ng/mL (n = 10), propofol at Ce of 0.5 µg/mL (n = 10), or sevoflurane at 0.2 minimum alveolar concentration (MAC) (n = 10), and recovery from the anesthetics. Study 2: NEPs were recorded at control and under administration of higher dose anesthetics: propofol at Ce of 0.5 and 1.0 µg/mL (n = 10) or sevoflurane at 0.2 and 0.5 MAC (n = 10). A P-value < 0.016 was considered statistically significant in multiple analyses. RESULTS: Study 1: Remifentanil at Ce of 1.0 ng/mL significantly suppressed the amplitude of NEPs (mean amplitude (standard deviation) of control vs. remifentanil administration: 16.8 µV (3.8) vs. 10.1 µV (2.5), P < 0.001). Propofol and sevoflurane did not suppress the amplitude significantly. Study 2: Propofol at Ce of 0.5 and 1.0 µg/mL and sevoflurane at 0.2 and 0.5 MAC did not suppress the amplitude significantly. CONCLUSION: The amplitude of A-δ fiber selective NEPs was suppressed by remifentanil but not propofol or sevoflurane. NEPs with intraepidermal electrical stimulation can assess the analgesic effect of anesthetics. CLINICAL TRIAL NUMBER: UMIN000038214 REGISTRY URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000043328.

Alkalized lidocaine in a tapered cuff suppresses endotracheal tube-induced hemodynamic changes: a randomized controlled trial.

PURPOSE: The use of an endotracheal tube (ET) cuff filled with alkalized lidocaine (AL) can suppress ET-induced emergence phenomena, such as hypertension, tachycardia and coughing, and postoperative sore throat (POST) and hoarseness (PH). The efficacy of intracuff lidocaine may vary depending on the cuff shape, but there has been no study on the effects of a tapered cuff filled with AL. We examined whether intracuff AL suppresses ET-induced emergence phenomena, POST and PH. METHODS: Sixty-two patients were enrolled in this study and the patients were randomly allocated to a group in which the tapered cuff was filled with AL (Group AL) and a group in which the tapered cuff was filled with normal saline (Group S). The primary outcomes of this study were changes in mean blood pressure (MBP) and heart rate (HR) at extubation. MBP, HR and the number of coughs were recorded before and up to 10 min after extubation. The degree of POST and the incidences of POST and PH were recorded at 15 min, 2 h and 24 h after extubation. RESULTS: Changes in MBP before extubation and HR before and after extubation were significantly lower in Group AL than in Group S (p < 0.025). The number of coughs at extubation and the incidence of PH at 2 h after extubation were significantly lower in Group AL than in Group S (p < 0.0001 and p = 0.014, respectively). CONCLUSION: AL in a tapered cuff significantly suppresses ET-induced cardiovascular changes in MBP and HR.

Effect of cerebrospinal fluid drainage pressure in descending and thoracoabdominal aortic repair: a prospective multicenter observational study.

PURPOSE: Cerebrospinal fluid drainage (CSFD) is recommended during open or endovascular thoracic aortic repair. However, the incidence of CSFD complications is still high. Recently, CSF pressure has been kept high to avoid complications, but the efficacy of CSFD at higher pressures has not been confirmed. We hypothesize that CSFD at higher pressures is effective for preventing motor deficits. METHODS: This prospective observational study included 14 hospitals that are members of the Japanese Society of Cardiovascular Anesthesiologists. Patients who underwent thoracic and thoracoabdominal aortic repair were divided into four groups: Group 1, CSF pressure around 10 mmHg; Group 2, CSF pressure around 15 mmHg; Group 3, CSFD initiated when motor evoked potential amplitudes decreased; and Group 4, no CSFD. We assessed the association between the CSFD group and motor deficits using mixed-effects logistic regression with a random intercept for the institution. RESULTS: Of 1072 patients in the study, 84 patients (open surgery, 51; thoracic endovascular aortic repair, 33) had motor deficits at discharge. Groups 1 and 2 were not associated with motor deficits (Group 1, odds ratio (OR): 1.53, 95% confidence interval (95% CI): 0.71-3.29, p = 0.276; Group 2, OR: 1.73, 95% CI: 0.62-4.82) when compared with Group 4. Group 3 was significantly more prone to motor deficits than Group 4 (OR: 2.56, 95% CI: 1.27-5.17, p = 0.009). CONCLUSION: CSFD is not associated with motor deficits in thoracic and thoracoabdominal aortic repair with CSF pressure around 10 or 15 mmHg.

Preoperative and postoperative complications of cerebrospinal fluid drainage in descending thoracic and thoraco-abdominal aortic aneurysm surgery: a single-center retrospective study.

PURPOSE: Cerebrospinal-fluid drainage (CSFD) has been performed to prevent paraplegia in descending thoracic or thoraco-abdominal aortic aneurysm (DTA/TAAA) surgery; however, CSFD itself has a risk of severe complications. We retrospectively investigated the incidence rates of CSFD-related preoperative and postoperative complications. METHODS: Patients who underwent DTA/TAAA surgery with a CSFD catheter that was inserted on the day before surgery were enrolled. The incidence rates of complications from spinal puncture until DTA/TAAA surgery were investigated as preoperative CSFD complications, and the incidence rates from DTA/TAAA surgery to postoperative day 7 were investigated as CSFD-related postoperative complications. RESULTS: Preoperative CSFD complications were analyzed in 123 cases. DTA/TAAA surgery was postponed due to bloody cerebrospinal fluid (2.5%) and due to meningitis (1.7%). The incidence rate of mild preoperative complications was 32.4%. Postoperative CSFD complications were analyzed in 108 cases. Intracranial hemorrhage occurred in 3.9% of cases in open surgery and other postoperative severe CSFD complications did not occur. The incidence rates of moderate/mild complications in open surgery were 2.6%/14.3% and those in TEVAR were 3.2%/19.4%. CONCLUSION: Bloody cerebrospinal fluid and meningitis, which are severe complications associated with spinal puncture, occurred within 1 day after spinal puncture. The incidence rates of moderate/mild complications were high in both the preoperative and postoperative periods. These results showed that CSFD catheter insertion and management should be performed carefully with consideration given to the risks and benefits of CSFD.

An unusual foreign body in the oral cavity: a case report from a patient safety point of view and literature review.

Accidental foreign bodies (FBs) in the oral cavity, airway, esophagus and breathing circuit associated with anesthetic procedures are rare but can cause serious and life-threatening complications. We here present a case in which an unusual FB in the oral cavity was found after emergence from general anesthesia. The FB was later identified as a melted cap of a felt-tip pen. We investigated the cleaning process for reusable materials and concluded that the FB was accidentally placed in the inner lumen of the reusable bite block during the cleaning process. We then performed a review of the literature on FBs other than those of dental origin which were entrapped in the oral cavity, pharynx, larynx, trachea, esophagus, and anesthetic breathing circuit due to anesthetic procedures. From our case and 53 cases found in the search, we concluded that 1) use of disposable medical devices is recommended, 2) FBs can easily migrate into the oral cavity and airway during anesthesia, 3) delayed FB recognition may be associated with difficult intubation situations, and 4) more attention should be paid to the possibility of any medical or non-medical device becoming an FB during anesthesia.

Another route of CO2 gas excretion independent of red blood cells in human lungs.

We demonstrated pulmonary arteriolar blood flow-mediated CO2 gas excretion in rabbit lungs. The shear stress stimulation produced CO2 gas in cultured human endothelial cells of pulmonary arterioles via the activation of F1/Fo ATP synthase. To confirm the findings in human subjects undergoing the operation with heart-lung machines, we aimed to evaluate the effects of a stepwise switch, from a partial to a complete cardiopulmonary bypass, of the circulatory blood volume (BV, 100% = 2.4 × cardiac index), on the end-expiratory CO2 pressure (PetCO2), maximal flow velocity in the pulmonary artery (Max Vp), the inner diameter (ID) of pulmonary artery, pulmonary arterial CO2 pressure (P mix v CO2), pulmonary arterial O2 pressure (P mix v O2), hematocrit (Hct), pH, the concentration of HCO3-, and base excess (BE) in mixed venous blood in 9 patients with a mean age of 72.3 ± 3.4 years. In addition, the effects of the decrease in Hct infused with physiological saline solution (PSS) on PetCO2 were investigated in the human subjects. An approximately linear relationship between the PetCO2 and Max Vp was observed. The pumping out of 100% BV produced little or no change in the Hct, pH, P mix v CO2, and P mix v O2, respectively. The hemodilution produced by intravenous infusion of PSS caused a significant decrease in the Hct, but not in the PetCO2. In conclusion, another route of CO2 gas excretion, independent of red blood cells, may be involved in human lungs.

Pseudohypoxic brain swelling and secondary hydrocephalus with pseudomeningocele after lumbar surgery: a case report.

BACKGROUND: Postoperative intracranial complications are rare in spine surgery not including cranial procedures. We describe an uncommon case of pseudohypoxic brain swelling (PHBS) and secondary hydrocephalus after transforaminal lumbar interbody fusion (TLIF) presenting as impaired consciousness and repeated seizures. CASE PRESENTATION: A 65-year-old man underwent L4-5 TLIF for lumbar spondylolisthesis and began experiencing generalized seizures immediately postoperatively. Computed tomography (CT) revealed diffuse cerebral edema-like hypoxic ischemic encephalopathy. He was transported to our hospital, at which time epidural drainage was halted and anti-edema therapy was commenced. His impaired consciousness improved. However, he suffered secondary hydrocephalus due to continuous bleeding from a dural defect and spinal epidural fluid collection 3 months later. Following the completion of dural repair and insertion of a ventriculoperitoneal shunt, his neurologic symptoms and neuroimaging findings improved significantly. CONCLUSIONS: PHBS can be considered in patients with unexpected neurological deterioration following lumbar spine surgery even with the absence of documented durotomy. This might be due to postoperative intracranial hypotension-associated venous congestion, and to be distinguished from the more common postoperative cerebral ischemic events-caused by arterial or venous occlusions-or anesthetics complications.

Cerebrospinal fluid drainage to prevent postoperative spinal cord injury in thoracic aortic repair.

BACKGROUND: Cerebrospinal fluid drainage (CSFD) is recommended as a spinal cord protective strategy in open and endovascular thoracic aortic repair. Although small studies support the use of CSFD, systematic reviews have not suggested definite conclusion and a large-scale study is needed. Therefore, we reviewed medical records of patients who had undergone descending and thoracoabdominal aortic repair (both open and endovascular repair) at multiple institutions to assess the association between CSFD and postoperative motor deficits. METHODS: Patients included in this study underwent descending or thoracoabdominal aortic repair between 2000 and 2013 at 12 hospitals belonging to the Japanese Association of Spinal Cord Protection in Aortic Surgery. We conducted a retrospective study to investigate whether motor-evoked potential monitoring is effective in reducing motor deficits in thoracic aortic aneurysm repair. We use the same dataset to examine whether CSFD reduces motor deficits after propensity score matching. RESULTS: We reviewed data from 1214 patients [open surgery, 601 (49.5%); endovascular repair, 613 (50.5%)]. CSFD was performed in 417 patients and not performed in the remaining 797 patients. Postoperative motor deficits were observed in 75 (6.2%) patients at discharge. After propensity score matching (n = 700), mixed-effects logistic regression performed revealed that CSFD is associated with postoperative motor deficits at discharge [adjusted odds ratio (OR), 3.87; 95% confidence interval (CI), 2.30-6.51]. CONCLUSION: CSFD may not be effective for postoperative motor deficits at discharge.

Endogenous Calcitonin Gene-Related Peptide Deficiency Exacerbates Postoperative Lymphedema by Suppressing Lymphatic Capillary Formation and M2 Macrophage Accumulation.

Lymphedema is a chronic condition caused by disruption of lymphatic vessels, which often occurs after invasive surgery. Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide produced by alternative splicing of the primary transcript of the calcitonin/CGRP gene (Calca). CGRP was initially identified as a neuropeptide released primarily from sensory nerves and involved in regulating pathophysiological nociceptive pain. However, recent studies have shown CGRP is also released from a variety of other cells and possesses multiple functions. In this study, CGRP knockout (-/-) mice were used to show the actions of endogenous CGRP in postoperative lymphedema. After generating a mouse postoperative tail lymphedema model, the edema was observed to be more severe in CGRP-/- mice than in wild-type mice. Numbers of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1)-positive lymphatic capillaries were decreased and lymphatic capillary formation-related factors were down-regulated in CGRP-/- mice. In addition, accumulation of M2 but not M1 macrophages was selectively reduced in the edematous tissue of CGRP-/- mice. Selective depletion of M2 macrophages decreased lymphatic capillary formation and worsened lymphedema in wild-type mice but not CGRP-/- mice, where numbers of M2 macrophages were already diminished. These findings suggest that endogenous CGRP acts to ameliorate postoperative lymphedema by enhancing lymphatic capillary formation and that M2 macrophages play critical roles. CGRP may be a useful therapeutic target for the treatment of postoperative lymphedema.

Effect of an aerosol box on tracheal intubation difficulty.

The aim of this study was to determine the effect of an aerosol box on tracheal intubation difficulty. Eighteen experienced anesthetists intubated the trachea of a manikin with a normal airway 6 times using a direct laryngoscope, a McGRATH™ MAC videolaryngoscope, or an airway scope AWS-S200NK videolaryngoscope with or without an aerosol box. Although the aerosol box prolonged the time to successful intubation and decreased the percentage of glottic opening (POGO) score when using a direct laryngoscope, the statistically significant differences were clinically irrelevant. When a McGRATH™ MAC and an AWS-S200NK were used, the times to successful intubation and POGO scores were comparable with and without the aerosol box. When using any of the laryngoscopes, there were no statistically significant differences in the Cormack-Lehane grade and peak force to maxillary incisors with and without the aerosol box. In summary, the effect of an aerosol box on tracheal intubation difficulty is not clinically relevant when an experienced anesthetist intubates the trachea in a normal airway condition.

Differential effects of sevoflurane and propofol on an electroretinogram and visual evoked potentials.

The purpose of this study was to simultaneously evaluate the effects of sevoflurane and propofol on an electroretinogram (ERG) and visual evoked potentials (VEPs). Twenty-four patients scheduled for elective surgery under general anesthesia were allocated randomly to receive either sevoflurane (group S) or propofol (group P). An ERG and VEPs were recorded in an awake state and during anesthesia with three different minimum alveolar concentrations (MAC; 0.5, 1.0, and 1.5) of sevoflurane in group S or with three different effect-site concentrations (Ce) of 2, 3, and 4 µg/ml by using a target-controlled infusion technique in group P. Sevoflurane and propofol had little effect on amplitudes of the ERG b-wave. Sevoflurane significantly attenuated the amplitudes of VEP N75-P100 at 0.5, 1.0, and 1.5 MAC. Propofol did not significantly decrease the amplitude of VEPs at Ce of 2 or 3 µg/ml but significantly decreased it at Ce of 4 µg/ml. In summary, propofol and sevoflurane at clinical concentrations had little effect on the amplitude of an ERG. Sevoflurane attenuated the amplitudes of VEPs even at low concentrations. Propofol also attenuated the amplitudes of VEPs to a lesser extent compared to sevoflurane.

Acute postoperative pain is correlated with the early onset of postpartum depression after cesarean section: a retrospective cohort study.

The primary purpose of this study was to evaluate the correlation between the intensity of acute postoperative pain and development of postpartum depression (PPD) after cesarean section (CS). The secondary purpose was to investigate perioperative risk factors for PPD detected in the postoperative period after CS. We retrospectively reviewed 615 women who had undergone CS between January 2017 and October 2019 in our hospital. The incidence of PPD was 22.7% on postoperative day (POD) 5 in the 247 women whose numerical rating scale (NRS) scores on POD3 were available. The severity of acute postoperative pain evaluated by NRS was higher in women with than in those without PPD on POD3 (P < 0.02). The independent risk factors for the onset of PPD on POD5 were being a primipara [adjusted odds ratio (aOR), 2.08; 95% confidence interval (CI), 1.03-4.20, P < 0.05], preoperative presence of chronic pain (OR, 4.44; 95% CI 1.82-10.81, P < 0.001), and NRS ≥ 2 on POD3 (aOR, 4.90; 95% CI 1.06-22.61, P < 0.05). Our findings suggest that assessing both acute postoperative pain and presence of PPD can inform the introduction of interventions in the early phase to prevent development of PPD after CS.

Prostanoid EP4 Receptor-Mediated Augmentation of I h Currents in Aß Dorsal Root Ganglion Neurons Underlies Neuropathic Pain.

An injury of the somatosensory system causes neuropathic pain, which is usually refractory to conventional analgesics, thus warranting the development of novel drugs against this kind of pain. The mechanism of neuropathic pain in rats that had undergone left L5 spinal nerve transection was analyzed. Ten days after surgery, these rats acquired neuropathic pain. The patch-clamp technique was used on the isolated bilateral L5 dorsal root ganglion neurons. The current-clamped neurons on the ipsilateral side exhibited significantly higher excitability than those on the contralateral side. However, only neurons with diameters of 40-50 µm on the ipsilateral side exhibited significantly larger voltage sags in response to hyperpolarizing current pulses than those on the contralateral side. Under the voltage clamp, only these neurons on the ipsilateral side showed a significantly larger density of an inward current at < -80 mV [hyperpolarization-activated nonselective cation (I h) current] with a rightward-shifted activation curve than that on the contralateral side. Ivabradine-an I h current inhibitor-inhibited I h currents in these neurons on both sides in a similar concentration-dependent manner, with an IC50 value of ∼3 µM. Moreover, the oral administration of ivabradine significantly alleviated the neuropathic pain on the ipsilateral side. An inhibitor of adenylyl cyclase or an antagonist of prostanoid EP4 receptors (CJ-023423) inhibited ipsilateral, but not contralateral I h, currents in these neurons. Furthermore, the intrathecal administration of CJ-023423 significantly attenuated neuropathic pain on the ipsilateral side. Thus, ivabradine and/or CJ-023423 may be a lead compound for the development of novel therapeutics against neuropathic pain.

Association Between Motor-Evoked Potentials and Spinal Cord Damage Diagnosed With Magnetic Resonance Imaging After Thoracoabdominal and Descending Aortic Aneurysm Repair.

OBJECTIVES: The authors investigated the association between intraoperative motor-evoked potential (MEP) changes and the severity of spinal cord infarction diagnosed with magnetic resonance imaging (MRI) to clarify the discrepancy between them, which was observed in patients with postoperative motor deficits after thoracic and thoracoabdominal aortic surgery. DESIGN: A multicenter retrospective study. SETTING: Motor-evoked potential <25% of control values was deemed positive for spinal cord ischemia. The severity of spinal cord infarction was categorized into grades A to D based on previous studies using the most severe axial MRI slices. The associations between MRI grade, MEP changes, and motor deficits were examined using logistic regression. PARTICIPANTS: Twenty-three of 1,245 patients (from 1999 to 2013, at 12 hospitals in Japan) were extracted from medical records of patients who underwent thoracic and thoracoabdominal aortic repair, with intraoperative MEP examinations and postoperative spinal MRI. INTERVENTIONS: No intervention (observational study). MEASUREMENTS AND MAIN RESULTS: Motor-evoked potential <25% of control value was associated significantly with motor deficits at discharge (adjusted odds ratio [OR], 130.0; p = 0.041), but not with severity of spinal cord infarction (adjusted OR, 0.917; p = 0.931). Motor deficit at discharge was associated with severe spinal cord infarction (adjusted OR, 4.83; p = 0.043), MEP <25% (adjusted OR, 13.95; p = 0.031), and combined deficits (motor and sensory, motor and bowel or bladder, or sensory and bowel or bladder deficits; adjusted OR, 31.03; p = 0.072) in stepwise logistic regression analysis. CONCLUSION: Motor-evoked potential <25% was associated significantly with motor deficits at discharge, but not with the severity of spinal cord infarction.

Transcranial motor-evoked potentials of laryngeal muscles for intraoperative neuromonitoring of the vagus nerve during thyroid surgery.

PURPOSE: The aim of this study was to elucidate normative features of vagal motor-evoked potentials (MEPs) induced by transcranial electrical stimulation (TES) and to determine the influence of functional decline of the recurrent laryngeal nerve (RLN) on vagal MEPs during thyroid surgery. METHODS: A total of 54 patients undergoing elective thyroid surgery under general anesthesia were enrolled in this study. Vagal MEPs induced by TES were measured from the vocal cord using one of two types of electrodes (wire type or wide and flat type) mounted on an endotracheal tube. We investigated the effects of stimulation intensity and train pulse number on vagal MEP amplitude, the time course of vagal MEP amplitude during surgery, and the effects of functional decline of the RLN on vagal MEPs. RESULTS: The success rate of vagal MEP monitoring with wide- and flat-type electrodes was significantly higher than that with wire-type electrodes. Reliable vagal MEPs were obtained at a stimulation intensity of approximately 300 V with 3 or more pulses in 91% of the patients without preoperative RLN palsy (RLNP), and the amplitude was augmented with increasing stimulation intensity and train pulse number. Vagal MEP amplitude decreased during thyroid surgery and then partially recovered at the end of surgery. Vagal MEP amplitude recorded from the electrode ipsilateral to preoperative RLNP was significantly lower than that on the contralateral intact side. CONCLUSION: Vagal MEPs induced by TES can be obtained with a high success rate during thyroid surgery and would reflect functional status of the RLN.

Clinical Utility of Intraoperative Motor-Evoked Potential Monitoring to Prevent Postoperative Spinal Cord Injury in Thoracic and Thoracoabdominal Aneurysm Repair: An Audit of the Japanese Association of Spinal Cord Protection in Aortic Surgery Database.

BACKGROUND: Spinal cord ischemic injury is the most devastating sequela of descending and thoracoabdominal aortic surgery. Motor-evoked potentials (MEPs) have been used to intraoperatively assess motor tract function, but it remains unclear whether MEP monitoring can decrease the incidence of postoperative motor deficits. Therefore, we reviewed multicenter medical records of patients who had undergone descending and thoracoabdominal aortic repair (both open surgery and endovascular repair) to assess the association of MEP monitoring with postoperative motor deficits. METHODS: Patients included in the study underwent descending or thoracoabdominal aortic repair at 12 hospitals belonging to the Japanese Association of Spinal Cord Protection in Aortic Surgery between 2000 and 2013. Using multivariable mixed-effects logistic regression analysis, we investigated whether intraoperative MEP monitoring was associated with postoperative motor deficits at discharge after open and endovascular aortic repair. RESULTS: We reviewed data from 1214 patients (open surgery, 601 [49.5%]; endovascular repair, 613 [50.5%]). MEP monitoring was performed in 631 patients and not performed in the remaining 583 patients. Postoperative motor deficits were observed in 75 (6.2%) patients at discharge. Multivariable logistic regression analysis revealed that postoperative motor deficits at discharge did not have a significant association with MEP monitoring (adjusted odds ratio [OR], 1.13; 95% confidence interval [CI], 0.69-1.88; P = .624), but with other factors: history of neural deficits (adjusted OR, 6.08; 95% CI, 3.10-11.91; P < .001), spinal drainage (adjusted OR, 2.14; 95% CI, 1.32-3.47; P = .002), and endovascular procedure (adjusted OR, 0.45; 95% CI, 0.27-0.76; P = .003). The sensitivity and specificity of MEP <25% of control value for motor deficits at discharge were 37.8% (95% CI, 26.5%-49.5%) and 95.5% (95% CI, 94.7%-96.4%), respectively. CONCLUSIONS: MEP monitoring was not significantly associated with motor deficits at discharge.

Prevalence of chronic postsurgical pain after thoracotomy and total knee arthroplasty: a retrospective multicenter study in Japan (Japanese Study Group of Subacute Postoperative Pain).

We performed a multicenter observational study to assess the prevalence and risk factors of persistent pain after lung cancer surgery and total knee arthroplasty (TKA) in the Japanese population. After receiving Ethics Committee approval, a retrospective chart review was performed for patients who underwent surgery at seven university hospitals in Japan in 2013. A total of 511 patients who underwent lung cancer surgery and 298 patients who underwent TKA were included. The prevalence of chronic postsurgical pain (CPSP) at 3 and 6 months was 18 and 12% after lung surgery and 49 and 33% after TKA, respectively. The prevalence of analgesic use at 3 and 6 months was 16 and 9% after lung surgery and 34 and 22% after TKA, respectively. In both groups, preoperative analgesic use was associated with CPSP. Anesthetic methods or techniques during both types of surgery did not significantly affect the prevalence of CPSP. This is the first study in which the prevalence of CPSP after lung surgery and TKA in Japanese population was extensively evaluated in a multicenter trial. Further prospective studies are needed to confirm the prevalence of CPSP in the Japanese population and to identify risk factors and prevention methods.

[A Perspective View on Peripheral Nerve Block of the Future: Preface and Comments].

Ultrasound-guided nerve blocks (UGNBs) have been gaining popularity since 2000 in Japan. This is not only because ultrasound technology has developed recently but also because remifentanil has become available in 2006 with the risk of opioids for recurrence of cancer after surgery shown in 2006. Thus, UGNBs have been employed widely in the anesthesiology field, and anes- thesiologist have tried to reduce consumption of opioid during perioperative periods by using UGNBs, non- steroidal anti-inflammatory drugs, acetoaminophen and so on; that is, multi-modal analgesic technique. In a special issue of this month, experts discuss the efficacy and use of UGNBs for the upper extremities, thorax, abdomen, and lower extremities. In these articles, they will highlight the data on clinical outcome for UGNBs and discuss specific limitations of UGNB. The articles will help readers to know much more about the future direction of UGNBs.