Patients scheduled to undergo colon surgery were randomly assigned to an oral rehydration therapy（ORT）group or a conventional group. In an ORT group, patients consumed maximum 1,000 mL of OS-1 until 2 hours before induction of anesthesia. Before induction of anesthesia, a catheter connected to a Vigileo monitor was placed in the radial artery of all patients. We then measured heart rate, blood pressure, arterial pressure-based cardiac output, cardiac index, stroke volume variation（SVV）for hemodynamic parameters and the amount of fluids patients consumed preoperatively. Results showed that the amount of drinking fluid volume was significantly greater and the number of patients who required a vasopressor and colloids was significantly lower in the ORT group than in the conventional group. Although blood pressures and heart rates remained unchanged after anesthesia induction in the ORT group, SVV in both groups was significantly higher than at baseline, which might predict fluid responsiveness.

We experienced a case of cardiac arrest due to coronary artery spasm on extubation after thymectomy. The patient was a 60-year-old male. He had several risk factors of coronary vasospasm including being a male, a smoker and a drinker in addition to abnormal of lipid metabolism, but he did not have any significant coronary abnormalities preoperatively. He underwent thymectomy under veno-venous bypass for hemodynamic instability, which required frequent administration of phenylephrine. Cardiac arrest occurred following hypotension and ST elevation on an electrocardiogram（ECG）after surgery. His spontaneous circulation recovered 2 minutes after cardiopulmonary resuscitation. There was cardiac dysfunction indicating anteroseptal abnormal wall motion on the ECG. The ECG change was transient and was resolved without any invasive intervention within several days after surgery. He was finally discharged from the hospital without any disabilities. Coronary artery spasm was strongly suspected as a cause of the cardiac arrest because of the positive result of a provocation test for coronary spasm after surgery. In addition to preoperative risk factors for coronary spasm, several intraoperative factors, including surgical invasiveness, situation of awakening and administration of an anesthesia-related agent, possibly led to coronary spasm.

Kommerell’s diverticulum is a rare anomaly of the aortic arch. Over the last 8 years, we experienced five patients who had a right-sided aorta with Kommerell’s diverticulum. A double-lumen tube or single-lumen tube with a blocker was used for anesthetic management during aortic replacement. In all of these patients, the diameter of the endotracheal tube was greater than the smallest diameter of the trachea. Three-dimensional images of the trachea, bronchus, aorta, and pulmonary artery showed two sites with the possibility of airway stenosis. One site was the trachea, which was surrounded by a vascular ring. The other site was the right main bronchus, which was located behind the ascending aorta and the right pulmonary artery, and was in front of the descending aorta. The stenosis tended to be located close to the carina, rather than the cricoid cartilage. When anesthetic management is performed with a single-lumen tube with a blocker, the endotracheal tube should be inserted deeply enough before the carina and bronchoscopy should be ready for use. A smaller endotracheal tube should be selected to avoid tracheal injury.

Randomized double-blind trials in western countries have failed to demonstrate the efficacy of fibrinogen concentrate（3-6 g）for perioperative hemostasis or demonstrate a reduction in blood transfusion in patients undergoing complicated cardiovascular surgery. The main reason for these negative findings in clinical trials is that the mean fibrinogen level of 170-180 mg/dL at the end of cardiopulmonary bypass is too high to induce the efficacy of fibrinogen concentrate and fresh frozen plasma is sufficiently effective for hemostasis in an area with a high level of fibrinogen. In our previous study, we demonstrated that the actual trigger level for fibrinogen concentrate was <130 mg/dL in thoracic aortic surgery, and the effective dose of fibrinogen was approximately 2-3 g per 50-70 kg in body weight. In the future, a new and safe approach that is based on objective study and clinical trials is sure to elucidate the trigger level and the effective dose of concentrated fibrinogen for patients undergoing cardiovascular surgery.

As the population ages in Japan, an increasing number of elderly patients are receiving surgical treatments under general anesthesia. Therefore, postoperative cognitive dysfunction（POCD）has been recognized as a common and important problem in elderly patients following surgery, in addition to delirium. Recent research suggests many risk factors of POCD such as old age, cognitive decline prior to surgery, cerebral white matter lesions, invasive surgical procedures, and certain kinds of anesthetic agents. On the other hand, the pathophysiological mechanism of POCD has not been clearly elucidated. Moreover, methods for evaluating cognitive dysfunction are controversial, and diagnostic criteria for POCD are still ambiguous. In this report, we describe the risk factors and potential pathogenesis of POCD based on previous studies while comparing it with post-stroke dementia because of similarities between the two conditions.

During emergence from general anesthesia, patients’ physiology changes dramatically in a very short period of time. It is a phase of transition from intraoperative controlled ventilation with a secured airway to spontaneous ventilation via patients’ natural airway. Modern short-acting drugs like propofol, desflurane and remifentanil enable very quick recovery in most patients. However, upper airway obstruction and aspiration are not negligible risks in the postoperative period. Despite tracheal extubation being a potentially critical event, its importance has not been adequately appreciated. Upper airway at the end of surgery is not exactly the same as at the beginning of surgery. Many factors, such as massive infusion, prolonged head-down position, and surgery around head and neck, can make a preoperative “easy airway” into a postoperative difficult airway. In addition to anatomical changes, physiological as well as pharmacological derangements affect patency of airways. Human factors including fatigue of anesthetists and time pressure for quick turnover of surgical schedule can also affect decision-making regarding extubation plans. The importance of non-technical skills such as situation awareness and good communication among those involved in the extubation process should be emphasized.

For anesthesiologists, extubation is a daily procedure, but its methodology is not standardized, and there are no detailed Japanese textbooks or guidelines on extubation. Anesthesiology residents in Japan must perform extubation with a board-certified specialist until they obtain status as a registered anesthesiologist, which requires at least two years of training. After that, residents have more opportunities to anesthetize alone, and fewer chances to consult with their superiors. It can be assumed that when anesthesia residents perform extubation alone, many have unanswered questions or have only a vague understanding of the procedure. It may be common for the resident to experience a frightening situation at the time of extubation. The author conducted a Web survey asking anesthesia residents what problems they face regarding extubation. This article will discuss what anesthesiology residents want to know about extubation based on the results of the survey.

Clinical decision-making in airway management depends on several factors such as patient characteristics, type of surgery, available resources, and the skill set of the anesthesia provider. This is true of tracheal extubation.

In 2012, the Difficult Airway Society developed guidelines for the management of tracheal extubation that include many recommendations based mainly on expert opinions.

This article focuses on how the author implements these guidelines in daily practice and verifies their validity and reliability.

In pediatric patients, preventing respiratory complications during extubation after surgery is an important consideration for anesthesiologists. We need to know the physiological and anatomical differences between children and adults. To minimize respiratory complications, anesthesiologists should consider risk factors, extubation techniques, and appropriate choice of anesthetics.

Close vigilance of respiratory status is also required after exubation.

There are many problems in double lumen tube extubation. First, there are few assistance devices for DLT intubation, so reliable intubation procedures are required for re-intubation especially in cases of difficult airway. Since video laryngoscope and equipment compatible with DLT intubation/extubation have become available in recent years, it is necessary to be familiar with their use and use them effectively. Moreover, the DLT extubation technique may affect the postoperative breathing state. Upon extubation, it is important to remove sufficient and effective airway secretions. In cases of pulmonary resection and pneumothorax operation, it is important to devise an extubation method that does not cause strong coughing in order to prevent the occurrence of air leaks after surgery.

Not only knowledge and technical skills but also non-technical skills including situation awareness and decision making are required to accomplish safe tracheal extubation. Most cases of unsuccessful tracheal extubation involve cognitive errors resulting from various forms of cognitive biases. Self-reflection on behaviors and thought processes supplied with feedback from senior mentors and colleagues are essential to improving cognitive skills. The experiential learning cycle involving concrete experience, reflective observation, abstract conceptualization and active experimentation is a fundamental process for health care providers to acquire professionalism as well as competence for patient safety. In this article, a case scenario of failure in tracheal extubation based on the author’s own experience was presented. Cognitive errors contributing to failure are analyzed in detail from the perspective of medical education as well as patient safety.

Among many regulatory systems that maintain arterial blood pressure, the arterial baroreflex system plays a dominant role in arterial pressure regulation responding within seconds to minutes after disturbances. We have quantified characteristics of the arterial baroreflex-mediated sympathetic arterial pressure regulation using white noise analysis, a method used in the engineering field. Experimental results indicate that neural regulation is much faster and stronger than humoral regulation, so circulatory control via neural stimulation should contribute to the management of circulation including the perioperative period. Nevertheless, difficulty in noninvasively constructing neural interface limits the application of neural stimulation for circulatory control. Further research is required to develop an easy and effective methodology for neural stimulation.

The arterial baroreflex regulates blood pressure, and some diseases with baroreflex failure cause severe orthostatic hypotension. Anesthesia also attenuates the baroreflex. Therefore, unexpected hypotension may occur as a result of bleeding or surgical manipulation under anesthesia. Anesthesiologists usually administer infusion and catecholamine to maintain blood pressure, but it is hard to use in patients with heart disease. We analyzed the baroreflex system using system engineering, and applied neuro-interface method to re-construct it to the outside of the body. We discuss the development of the “bionic baroreflex system”, an artificial baroreflex system.

We have reported that there were many patients with myasthenia gravis（MG）whose response to rocuronium was similar to patients without MG. The efficacy of the reversal of rocuronium-induced neuromuscular blockade by sugammadex has also been reported in patients with MG. Therefore, while the use of rocuronium in patients with MG seems to have become safer, we experienced three unsuccessful postoperative extubations in patients with MG. Their response to rocuronium was increased and two of them could not achieve complete recovery of train-of-four（TOF）ratio after administration of sugammadex.

We also experienced cases in which the residual neuromuscular blockade could not be detected by TOF ratio, which evaluated the function of the presynaptic nicotinic acetylcholine receptors. First twitch（T1）height of TOF stimulation monitoring, which can usually be omitted in patients without MG, is needed to evaluate the function of postsynaptic nicotinic acetylcholine receptors. Because the location of the impaired receptors（presynaptic or postsynaptic）and the degree of their impairment seem to differ among individual patients with MG, not only TOF ratio but T1 height must be monitored to evaluate the residual neuromuscular blockade in patients with MG.

With the increase in elderly surgical patients, anesthesiologists are forced to take care of many elderly patients these days. However, the incidence of postoperative complications is higher in elderly patients, with respiratory complications being the most common. In addition, the use of neuromuscular blocking agents（NMBAs）is known as a risk factor for postoperative respiratory complications. To make matters worse, the effect of NMBAs tends to be prolonged in elderly patients, so they have a high risk of residual neuromuscular blockade postoperatively. In addition, many recent reports indicate that deep neuromuscular blockade improves surgical conditions. These facts have led to increases in the amounts of neuromuscular blocking agents used. Sugammadex is a quick and steady antagonist of neuromuscular blocking agents. It may reduce postoperative residual neuromuscular blockade and result in decreases in respiratory complications.

The administration of general anesthetics may potentially cause adverse effects such as long-term neurocognitive impairment induced by neuroapoptosis. Although many investigations have been made, the mechanism of these effects on the central nervous system（CNS）remains unclear. Previous studies have denied such adverse effects of general anesthetics on the immature CNS. In the 2000s, however, ketamine, nitrous oxide, midazolam, isoflurane and propofol were found to induce widespread neuroapoptosis in infant animal models. Since then, many arguments regarding the neurotoxicity of general anesthetics have been made. The stimulation of GABA or NMDA receptors may lead to neuroapoptosis in infant animal models. Furthermore, a recent study suggests that general anesthetics can suppress synaptogenesis in an infant rodent model. In humans, accumulating retrospective data suggest that general anesthetics may produce long-term cognitive impairments, whereas prospective studies such as the PANDA and GAS trials have emphasized the safety of general anesthetics for the developing brain in healthy children. However, these prospective studies leave an important question unanswered：the impact of repeated and prolonged exposure to anesthesia in children. Further studies examining the noxious effect of general anesthetics on the developing brain in humans are essential.

It is very difficult to manage the respiratory status of pediatric patients during anesthesia because children’s respiratory physiology changes dramatically from neonate to teenager. Anesthesiologists have to take particular care with each patient（age, body weight, height）to determine adequate ventilator setting according to idiosyncrasy. In addition, anesthesiologists have to understand the respiratory physiology of pediatric patients according to age：changes in respiratory rate, relatively narrow airway compared to adult patients, alveolar size and amount, stiffness of rib cage, etc. We select adequate tracheal tubes and set ventilator settings. It is also crucial to understand the difference in respiratory physiology between anesthetized mechanical ventilation and spontaneous breathing to manage pediatric patients.

The development of ultrasound anatomy has led to various approaches such as the shamrock view for lumbar plexus block, adductor canal block, and subsartorial canal approach for saphenous nerve and some branches block, and several approaches for obturator nerve block. Peripheral nerve block should be performed at more distal sites to prevent the motor weakness for postoperative pain and lower extremities pain.

Regional anesthesia for upper limb has used to be expert technology even with electric stimulation technique for brachial plexus blocks. In the past decade, ultrasound guided upper extremity peripheral nerve block has become popular among Japanese anesthesiologists. This technique improves the visualization of nerves and control of needle movement and spread of injected local anesthetics solution, and can therefore reduce the amount of local anesthetic required. Moreover, selective administration of an anesthetic to specific nerve/sensory branches decreases the incidence of unnecessary block preserves motor function and enables diversified hand surgery.

Ultrasound-guidance has improved the techniques and safety of neuraxial block in the 21st century. Measurement of distance from skin to the dura has contributed to a decrease in the frequency and time required for epidural puncture and an increase in its safety. Success rates of caudal block, epidural puncture for patients with scoliosis or obesity, and pediatric epidural block have also been increased by prescan using ultrasonography. Advances in ultrasound machines are expected to provide safer and reliable neuraxial block.

Background：Transmuscular quadratus lumborum muscle block provides analgesia for the lower limb. We report our experience of a case that was managed by general anesthesia and transmuscular quadratus lumborum muscle block during pelvic fixation performed prior to femoral neck fracture surgery.

Case：An 84-year-old female；height 149 cm；weight 50 kg. Open reduction and internal fixation（γnail）for femoral neck fracture sustained in a traffic injury was scheduled after fixation of the pelvic fracture. The affected side was raised on a pillow, and the patient was placed in the half lateral decubitus position. Despite some difficulty with the manipulation of ultrasound transducer, we managed to deposit 30 mL of levobupivacaine into the fascial plane between quadratus lumborum and psoas major muscles. Sevoflurane and fentanyl were used to maintain general anesthesia. The NRS immediately after surgery was 0. About 13 hours later, the patient began to experience pain during body movements.

Conclusion：Transmuscular quadratus lumborum muscle block was successfully administered with the patient in the supine position for external pelvic fixation.