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At present, there is no method for predicting oil retention applicable to various working fluids. Oil retention characteristics in compressor suction lines are studied and a general method for predicting oil retention is established. The database of oil retention in suction lines is established according to experimental values in the public literature. After analyzing the influencing factors, a correlation of the volume ratio of oil retention in the database is fitted. According to the correlation and the state of working fluid at the inlet of suction line, the amount of oil retention can be predicted. In addition, oil retention of R32/PVE VG68 in suction lines is tested. A comparison of the experimental values and the prediction values indicate that for the flow of R32/PVE VG68 in suction lines, the calculation method can accurately show the variation trend of oil retention with various factors, and can accurately predict the amount of oil retention under different conditions.

Objective: Prevention of acute pressure injuries (PS) is critical in patients undergoing certain surgeries. This type of pressure injury can develop during and after surgery, causing unnecessary pain and complications for the patient. However, preventing PS in these high-risk patients may present some challenges and require specific nursing measures. To explore the clinical effects of special pressure ulcer intervention combined with gel positioning pad intervention on the prevention of acute stress injury in patients undergoing long-term lateral position spinal surgery., Methods: The simple randomization method was used in this study; 100 patients with lateral position spinal surgery from March 2022 to March 2023 were selected as research subjects and were divided into an observation group and control group with 50 cases in each group by the random number table method. The control group was given routine intervention, and the observation group carried out special pressure ulcer intervention and gel positioning pad intervention. Special pressure ulcer intervention was performed, using appropriate surface support to relieve pressure, keeping the patient's skin clean and dry, and turning regularly to relieve pressure. In addition, we use a gel positioning pad intervention to disperse pressure, improve local blood circulation, and reduce the risk of pressure injuries. The occurrence of acute stress injury, VAS scores at different time points after surgery, local skin infrared thermography analysis results at 72 hours after surgery, incidence rates of complications and nursing satisfaction were compared between the two groups of patients., Results: The incidence rates of acute stress injury during surgery, within 2 hours after surgery and within 72 hours after surgery in the observation group were lower than those in the control group (P < .0046). The number and area of injury in the observation group were smaller than those in the control group (P < .0037). The National Pressure Ulcer Advisory Panel (NPUAP) grading of acute stress injury in the observation group was lower compared with that in the control group (P < .0021). The pain VAS scores in the observation group at 2 hours, 24 hours and 72 hours after surgery were lower than those in the control group (P < .001). The local skin infrared thermography analysis temperature values of the neck, shoulder, hip, knee and ankle were lower in the observation group than those in the control group at 72 hours after surgery (P < .001). The incidence rates of postoperative lumbago and shoulder-neck pain in the observation group were lower than those in the control group (P < .001). The scores of three aspects of nursing technology and nursing operation satisfaction, service attitude and humanistic care satisfaction, and nursing environment satisfaction were higher in the observation group than compared to the control group (P < .001). The findings of this study highlight the importance of specific pressure ulcer interventions that can be widely used in clinical practice and have the potential to reduce the incidence of pressure injuries and improve patient satisfaction with care., Conclusion: Special pressure ulcer intervention combined with gel positioning pad intervention has a good preventive effect on acute stress injury in patients undergoing long-term lateral position spinal surgery. Limitations of this study include the small sample size and single study institution, which may affect the external validity of the study. In addition, data collection in this study was limited to a specific time period and does not reflect long-term outcomes. Future studies could consider multi-center, broader samples, and longer follow-up to confirm the benefits of these interventions and to investigate in depth the long-term rehabilitation and quality of life of patients.