Lower extremity peripheral nerve block for total knee arthroplasty in a patient with chronic inflammatory demyelinating polyneuropathy: A case report.

RATIONALE: Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disorder that affects the peripheral nerves, leading to weakness and sensory symptoms. CIDP is a rare disease, and few studies have reported on anesthetic management in patients with this condition, especially the peripheral nerve block (PNB). Therefore, a safe and standardized anesthetic approach remains to be established. This case report aims to address this gap in evidence by documenting our experience with PNB in a patient with CIDP undergoing surgery. It contributes significantly to expanding the range of anesthetic options and enhancing perioperative outcomes for patients with CIDP. PATIENT CONCERNS: A 58-year-old woman diagnosed with CIDP was scheduled to undergo left total knee arthroplasty due to osteonecrosis. We anticipated postoperative pain and aggravation of neurological symptoms. DIAGNOSIS: CIDP. INTERVENTIONS: To manage the postoperative pain, we planned a combination of general anesthesia (GA) and lower extremity PNBs, viz. the tibial and femoral nerve blocks, supplemented with intravenous patient-controlled analgesia. An initial dose of fentanyl 50 µg was administered as analgesia. The tibial and femoral nerves were identified using a peripheral nerve stimulator in conjunction with an ultrasonic echo device while the patient was conscious, to minimize the risk of nerve injury. The tibial and femoral nerve blocks were performed with 20 mL of ropivacaine (0.25%) and dexamethasone 2.2 mg, respectively. Subsequently, we administered fentanyl and ketamine and initiated continuous infusion of remifentanil. Thereafter, propofol 120 mg was administered intravenously over a span of 1 minute, followed by continuous infusion at 4 mg/kg/h. Upon confirming loss of consciousness, we induced GA using a supraglottic airway device without using muscle relaxants. For postoperative analgesia, we administered acetaminophen 1000 mg. OUTCOMES: The patient experienced no pain immediately after surgery, and good analgesia was achieved subsequently without worsening of sensory symptoms during rehabilitation. LESSONS: We achieved effective anesthetic management in a patient with CIDP by combining GA with nerve stimulation and ultrasound-guided PNB. It is crucial to devise a personalized anesthesia plan that focuses on the patients' safety and comfort while minimizing risk in patients with CIDP.

Effective anesthetic management with remimazolam and ketamine without muscle relaxants for parotidectomy in a patient with myotonic dystrophy: A case report.

RATIONALE: Patients with myotonic dystrophy (DM) are highly sensitive to anesthetics, muscle relaxants, and opioids, necessitating appropriate anesthetic management. Recently, remimazolam, an ultra-short-acting benzodiazepine, has been approved for use as a general anesthetic in Japan, and patients with DM have reportedly been treated with remimazolam. However, to the best of our knowledge, no study has reported on endotracheal intubation without the use of muscle relaxants under anesthetic management with remimazolam, nor on the combination of remimazolam and ketamine. PATIENT CONCERNS: A 23-year-old man was referred to our hospital for right parotidectomy and diagnosed with DM just before surgery. At the surgeon's discretion, he was scheduled to undergo nerve monitoring to preserve the facial nerve. DIAGNOSIS: Myotonic dystrophy. INTERVENTIONS: We planned total intravenous anesthesia without muscle relaxants and selected remimazolam for anesthesia. Our aim was to prevent the intraoperative or postoperative complications associated with propofol and inhalational anesthetics. Additionally, we selected multimodal analgesia, including ketamine, to avoid opioid use. General anesthesia was induced with ketamine 30 mg, remifentanil 0.72 µg/kg/min, and remimazolam 12 + 6 mg. Endotracheal intubation was performed under videolaryngoscopy without the use of muscle relaxants. For postoperative analgesia, we administered additional doses of ketamine 20 mg and acetaminophen 1000 mg, and the surgeons infiltrated 8 mL of xylocaine 0.5% with epinephrine into the skin incision before starting the surgery. Intraoperative anesthesia was maintained with remimazolam 0.9 to 1.0 mg/kg/h and remifentanil 0.26 to 0.50 µg/kg/min. Flumazenil was administered for rapid awakening and safe extubation. All vitals, including the bispectral index, were stable during surgery. OUTCOMES: The patient did not develop facial nerve paralysis, sore throat, or hoarseness, nor did he have any memory of the surgery. Good postoperative analgesia was achieved. LESSONS: We achieved effective anesthetic management using remimazolam without muscle relaxants in a patient with DM. Furthermore, the combination of remimazolam and ketamine provided good sedation and postoperative analgesia.

Accidental epidural catheter removal rates and strength required for disconnection: a retrospective cohort and laboratory study.

BACKGROUND: Epidural catheters are associated with certain risks such as accidental epidural catheter removal, including dislodgement and disconnection. Globally, neuraxial connector designs were revised in 2016 to provide new standardization aimed at decreasing the frequency of misconnections during the administration of medications. However, no studies have investigated accidental epidural catheter removal after the revised standardization. This study aimed to examine differences in dislodgement and disconnection rates associated with different catheter connector types, and to investigate the linear tensile strength required to induce disconnection. METHODS: This retrospective cohort study included adult patients who underwent elective surgery and received patient-controlled epidural analgesia. Patients were divided into groups according to the type of catheter connection used: old standard, new standard, and new standard with taping groups. Furthermore, we prepared 60 sets of epidural catheters and connectors comprising 20 sets for each of the old, new, and taping groups, and used a digital tension meter to measure the maximum tensile strength required to induce disconnection. RESULTS: This clinical study involved 360, 182, and 378 patients in the old, new, and taping groups, respectively. Dislodgement rates did not differ statistically among the three groups, while there was a significant difference in disconnection rates. Propensity score matching analysis for disconnection rates showed no difference between the old and new groups (2.8% vs. 4.5%, p = 0.574), while the new group had higher rates than the taping group (6.5% vs. 0%, p = 0.002). This laboratory study identified that a tensile strength of 12.41 N, 12.06 N, and 19.65 N was required for disconnection in the old, new, and taping groups, respectively, and revealed no significant difference between the new and old groups (p = 0.823), but indicated a significant difference between the new and taping groups (p < 0.001). CONCLUSIONS: This clinical study suggested that dislodgement rates did not change among the three groups. Both clinical and laboratory studies revealed that disconnection rates did not change between the old and new connectors. Moreover, as a strategy to prevent accidents, taping the connecting points of the catheter connectors led to an increase in the tensile strength required for disconnection.

Successful peripheral nerve block under dexmedetomidine sedation for femoral neck fracture fixation in a 97-year-old patient.

Hip fracture is a common injury in elderly patients. In Japan, the number of super-old patients-age >90 years-with hip fractures has increased drastically over time. Available strategies for anaesthetic management for hip fracture surgery include general anaesthesia, neuraxial anaesthesia and peripheral nerve block. However, general and neuraxial anaesthesia are often avoided for various reasons, particularly in elderly patients. In recent years, peripheral nerve block has proven effective in various surgical procedures. Additionally, dexmedetomidine exhibits neuroprotective effects and has been used safely in super-old patients. Herein, we demonstrate successful anaesthetic management with peripheral nerve block under dexmedetomidine sedation for open reduction and internal fixation of a femoral neck fracture in a 97-year-old patient.

Spinal anesthesia for muscle biopsy in an infant with a suspected neuromuscular disorder: a case report.

BACKGROUND: Neuromuscular disorders (NMDs) occur in different forms and are generally diagnosed using muscle biopsy. Among the available anesthetic management options for infants with a suspected NMD are general anesthesia (GA) and regional anesthesia (RA), including spinal anesthesia (SA). Anesthesia selection is often challenging from the point of potential airway risks and anesthetic drug-related complications. CASE PRESENTATION: A 6-month-old male infant repeatedly underwent endotracheal intubation and extubation after birth because of respiratory muscle weakness and copious secretions. He was suspected of having NMD and was scheduled for muscle biopsy. His generalized hypotonia and decreased respiratory function presented a potentially difficult airway and complicated the selection of an appropriate anesthetic method. We selected SA and dexmedetomidine, which are safe for infants. CONCLUSION: We report the successful and effective anesthetic management of SA and dexmedetomidine in an infant with a suspected NMD.

Severe Hypermagnesemia with Normal Renal Function Can Improve with Symptomatic Treatment.

Hypermagnesemia is a rare disorder and commonly occurs in patients with renal dysfunction. Supportive therapy for hypermagnesemia consists of administration of high-volume fluids, calcium preparation, diuretics, and, in severe cases, hemodialysis. Few reports have described severe hypermagnesemia patients with normal renal function who improved without hemodialysis. A 56-year-old woman presented with a history of constipation in spite of taking constipation medicine, including MgO. She was brought to our emergency department due to vomiting and diffuse distension of the abdomen. Sudden vomiting, weakness, and lower level of consciousness occurred during examination. Her blood pressure dropped to 77/34 mmHg, and deep tendon reflexes of the limbs disappeared. Abdominal computed tomography showed bowel distension with wall edema, and biochemical testing showed serum Mg at 13.5 mg/dl. She was diagnosed with severe hypermagnesemia associated with intestinal obstruction and administered intravenous loop diuretics and calcium preparation in addition to high volumes of normal saline. As the serum Mg level steadily declined, her level of consciousness returned to usual. This case suggests that severe hypermagnesemia can occur in patients with normal renal function and constipation under MgO. Severe hypermagnesemia with normal renal function can improve with symptomatic treatment without hemodialysis.

When Ontogeny Matters: A New Japanese Species of Brittle Star Illustrates the Importance of Considering both Adult and Juvenile Characters in Taxonomic Practice.

Current taxonomy offers numerous approaches and methods for species delimitation and description. However, most of them are based on the adult characters and rarely suggest a dynamic representation of developmental transformations of taxonomically important features. Here we show how the underestimation of ontogenetic changes may result in long term lack of recognition of a new species of one of the most common ophiacanthid brittle stars (Echinodermata: Ophiuroidea) from the North Pacific. Based on vast material collected predominantly by various Japanese expeditions in the course of more than 50 years, and thorough study of appropriate type material, we revise the complex of three common species of the ophiuroid genus Ophiacantha which have been persistently confused with each other. The present study thus reveals the previously unrecognized new species Ophiacantha kokusai sp.nov. which is commonly distributed off the Pacific coast of Japan. The new species shows developmental differentiation from the closely related species Ophiacantha rhachophora H. L. Clark, 1911 and retains clearly expressed early juvenile features in the adult morphology. Another species, Ophiacantha clypeata Kyte, 1977, which had been separated from O. rhachophora, is in turn shown to be just a juvenile stage of another North Pacific species, Ophiacantha trachybactra H.L. Clark, 1911. For every species, detailed morphological data from both adult and juvenile specimens based on scanning electron microscopy are presented. A special grinding method showing complex internal features has been utilized for the first time. For all three species in this complex, a clear bathymetric differentiation is revealed: O. rhachophora predominantly inhabits shallow waters, 0-250 m, the new species O. kokusai lives deeper, at 250-600 m, and the third species, O. trachybactra, is found at 500-2,000 m. The present case clearly highlights the importance of considering developmental transformations, not only for a limited number of model organisms, but as part of the taxonomic process.