Objective:To compare the effects of ultrasound-guided dynamic needle tip positioning (DNTP) and long axis in-plane (LAX-IP) techniques for axillary vein puncture and catheterization.Methods:One hundred Society of Anesthesiologists physical statusⅠ-Ⅲ patients of both sexes, aged 18-64 yr, with body mass index of 20-28 kg/m 2, scheduled for elective axillary vein cannulation, were divided into 2 groups ( n=49 each) using the random number table method: DNTP group and LAX-IP group.Axillary vein puncture was performed using DNTP technique and LAX-IP technique under ultrasound guidance in DNTP group and LAX-IP group, respectively.Successful puncture at first attempt, overall successful catheterization, the number of needle tip redirection, and axillary vein puncture time and catheterization time were recorded.The occurrence of complications such as axillary artery puncture, posterior wall penetration of axillary vein, hematoma formation, pneumothorax, and nerve injury was recorded. Results:Compared with group LAX-IP, the success rate of puncture at first attempt was significantly increased, the number of cases required needle redirection was decreased, and the puncture time was shortened ( P<0.05), and no significant change was found in the logarithm of the posterior wall penetration of axillary vein in group DNTP ( P>0.05). No complications such as arterial puncture, hematoma, pneumothorax, or nerve injury occurred in two groups. Conclusions:Compared with LAX-IP technique, ultrasound-guided DNTP technique can dynamically observe the position of the needle tip, the operation is simple and safe, and it is worthy of clinical promotion when used for axillary vein puncture and cannulation.

Objective:To identify the risk factors for supine hypotension syndrome (SHS) after spinal anesthesia and establish a predictive model in parturients.Methods:The medical records from pregnant women undergoing elective cesarean section were retrospectively analyzed. According to the standard that SBP dropped by 30 mmHg or below 80 mmHg after spinal anesthesia, the parturients were divided into non-SHS group and SHS group. The general data from patients and difference of external iliac vein flow (ΔIVF) during postural changes before anesthesia were collected. The factors with statistically significant differences between groups were included in the logistic regression model, the risk factors were identified and the weighted score regression prediction model was established, and the receiver operating characteristic curve was drawn to evaluate the model.Results:There were 64 parturients developed SHS after spinal anesthesia, with an incidence of 54.7%. Logistic regression analysis showed that fetal abdominal circumference, amniotic fluid index, ΔIVF and consumption of norepinephrine were independent risk factors for SHS after spinal anesthesia. The area under the receiver operating characteristic curve was 0.983, 95% confidence interval was 0.968-0.999, the sensitivity was 90.6%, the specificity was 96.2%, and the Youden index was 0.868. The prediction model of the line chart was tested by Hosmer-Lemshow, P=0.984, and the C index visualized the line chart model was 0.983. Conclusions:Fetal abdominal circumference, amniotic fluid index, ΔIVF and consumption of norepinephrine are independent risk factors for SHS after spinal anesthesia in parturients, and the risk prediction model can effectively predict the occurrence of SHS after spinal anesthesia.

Objective:To investigate the early and middle term clinical efficacies of 3D-printed metal prostheses in the reconstruction of bone defects after osteotomy in malignant bone tumors.Methods:A total of 34 patients with malignant bone tumors of lower extremity femur and tibia who underwent 3D printing individualized metal prosthesis replacement surgery in the Department of Bone and Soft Tissue of Affiliated Cancer Hospital of Zhengzhou University from March 2019 to March 2022 were retrospectively analyzed. There were 23 males and 11 females, with an average age of 19.1±15.2 years (range, 7-80 years). There were 22 children and adolescents younger than 18 years old. There were 3 cases in the proximal femur, 15 cases in the middle and distal femur, 10 cases in the proximal tibia and 6 cases in the distal tibia. According to the final pathological diagnosis, 24 cases of osteosarcoma, 6 cases of Ewing's sarcoma, 2 cases of undifferentiated sarcoma, 1 case of osteosarcoma, and 1 case of malignant giant cell tumor of bone were enrolled in this study. Postoperative complications, wound healing, periprosthetic fracture and aseptic loosening, tumor outcome (evaluated by tumor control evaluation criteria), and length difference of lower limbs were recorded. Response evaluation criteria in solid tumor (RECIST) was used to evaluate tumor outcomes. Prosthetic-bone interface healing was evaluated postoperatively, and the function was evaluated based on Musculoskeletal Oncology Society (MSTS) 93.Results:The length of lesions was 70-240 mm in 34 patients, with an average of 125.5±35.4 mm. The length of osteotomy was 80-275 mm, with an average of 160.2±33.9 mm. No tumor was found on the osteotomy surface. The customized prosthesis was firmly installed and closely matched with the side of the preserved articular surface. There were 2 patients with local incision fat liquefaction and 4 patients with superficial wound infection, which healed after debridement and antibiotic treatment. One distal tibia osteosarcoma case developed severe periprosthetic infection 2 months after surgery, resulting in prosthesis implantation failure, limb movement pain and poor ankle function. After removal of the prosthesis, infection control and osteogenesis with the Ilizarov technique, the infection was completely controlled and local osteogenesis was possible. The remaining 33 patients had a good prosthetic-bone interface union. One case was found to have localized bone resorption on the contact surface of the prosthesis 7 months after operation, but the metal prosthesis and screws were not loose. The incisions healed well in other patients, without infection, prosthesis loosening, fracture or other complications. All patients survived and were followed up for 13.8±5.6 months (range, 7-27 months). During the follow-up, there was no recurrence of tumor at the osteotomy end in all patients, but 5 patients developed lung metastasis. At the end of the last follow-up, all patients survived. Among them, 16 patients had unequal length of lower limbs, including 10 cases within 2 cm, 3 cases between 2-5 cm, and 3 cases over 5 cm. With the exception of one patient whose prosthesis was removed due to infection, the MSTS 93 of the other patients was 24.9±2.2 (range, 19-28), and were rated as excellent in 26 cases and good in 7 cases. According to the RECIST evaluation criteria, 26 of 34 patients had complete response, 5 had disease progression, and 3 had stable disease.Conclusion:3D printed metal prosthesis is one of the effective methods for the treatment of bone defects after resection of malignant bone tumors in lower limbs, which is safe, reliable and has satisfactory early curative effect.

The purpose of this study was to reveal the resistance mechanism of Mycoplasma bovis from Xizang yaks to macrolide antibiotics and provide theoretical basis for clinical medication.In this study,10 strains of Mycoplasma bovis from Xizang yaks were tested for drug sensitivity to macrolide antibiotics using the micromethod,and sensitive strains were induced to be highly resist-ant in vitro.The results showed that all 10 strains of Mycoplasma bovis exhibited varying degrees of resistance to macrolide antibiotics.However,through methylation enzyme and inactivation en-zyme gene detection and analysis,it was found that there was no methylation enzyme encoded by the methylation enzyme gene and no resistance mechanism mediated by macrolide inactivation en-zymes,indicating that there were no mutations in the target gene loci of the sensitive and resistant strains.However,highly resistant strains in vitro have mutations at the domain Ⅱ,L22,and even L4 target gene loci,indicating that if two or more target gene amino acid loci undergo mutations,highly resistant strains can be produced.After testing with active efflux systems,it was found that there were no active efflux systems using macrolide antibiotics as substrates.It can be seen that the strain of Mycoplasma bovis from Xizang yaks is prone to mutation under the pressure of high con-centrations of macrolides,and there are mutations in two or more target gene amino acid sites,which is prone to produce highly resistant strains.