BACKGROUND： Cryoanalgesia at -50 ℃ for 90 seconds yields effective pain relief following thoracotomy. In China, -50 ℃ is a common temperature for intercostal cryoanalgesia following thoracotomy. However, experiment...BACKGROUND： Cryoanalgesia at -50 ℃ for 90 seconds yields effective pain relief following thoracotomy. In China, -50 ℃ is a common temperature for intercostal cryoanalgesia following thoracotomy. However, experimental results vary. OBJECTIVE： To explore intercostal nerve pathological changes at -70 ℃ for various freezing times by studying canines, and to evaluate long-term clinical efficacy of intercostal nerve cryoanalgesia for postoperative pain relief based on the animal experiments. DESIGN, TIME AND SETTING： A comparative animal study was performed at the Animal Experimental Center of the General Hospital of the People＇s Liberation Army. Based on results from the animal study, a randomized, controlled, clinical trial was performed at the Department of Thoracic Surgery of the General Hospital of the People＇s Liberation Army between October 2006 and October 2008. PARTICIPANTS： A total of 120 patients undergoing posterolateral single incision Iobectomy at the Department of Thoracic Surgery of PLA General Hospital between October 2006 and October 2008 were selected. Nervous system diseases were excluded. METHODS： Animal experiment： 8 anaesthetized, mixed-breed dogs were used. The intercostal nerves （costal bone 6-10） were frozen at -70 ℃ for varying times （30, 60, 90, 120, and 180 seconds）. Clinical study： 120 patients were randomly assigned to 2 groups （n = 60）. In the cryoanalgesia group, the intercostal nerves were frozen prior to chest closure, and 4 costal nerves （1 at incision level, 2 above and below incision, and 1 at drainage tube level） were frozen for 90 seconds at-70 ℃, respectively. Intercostal nerves were not frozen in the control group patients. Dolantin was used to relieve postoperative pain in patients from both groups. MAIN OUTCOME MEASURES： Pathological changes in frozen intercostal nerves were examined at days 1, 10, 30, and 60 following freezing. Following surgery, the degree of postoperative pain in all patients was evaluated by visual analogue scale at days 1,3, 5, 9, 30, 60, 90, and 180. Dolantin doses at days 1, 3, 5, 9 post-surgery and postoperative complications were noted. RESULTS： Nerve damage progressively increased with length of freezing time at -70 ℃, and recovery time from damage was gradually increased. After freezing for 90 seconds, the nerves exhibited obvious histopathological damage, and then completely recovered. In addition, after freezing for 180 seconds, the histopathological changes in nerves were reversible. In the clinical study, visual analogue scale scores were significantly less in the cryoanalgesia group compared with the control group （P 〈 0.01）, which was maintained over 30 days. In the cryoanalgesia group, the mean dolantin dose administered and postoperative complications were significantly reduced compared with the control group （P 〈 0.01）. CONCLUSION： Freezing of the intercostal nerve at -70 ℃ for 90 seconds is a safe and long-term effective method for relieving post-thoracotomy pain.展开更多
Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 61 steel.Plasma nitrocarburizing was conducted for 12 h at 540℃in the nitrogen, hydrogen and ...Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 61 steel.Plasma nitrocarburizing was conducted for 12 h at 540℃in the nitrogen, hydrogen and methane atmosphere to produce theε-Fe-（2-3）（N,C） phase.The compound layer produced by plasma nitrocarburising was predominantly composed ofε-phase,with a small proportion ofγ′-Fe-4 （N,C） phase. The thickness of the compound layer and the diffusion layer are about 10μm and about 200μm,respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of 500℃for 1 h.The very thin magnetite （Fe-3O-4） layer of 1-2μm in thickness on top of the compound layer was obtained.Anodic polarization test revealed that plasma nitrocarburizing process contributed a significant improvement of corrosion resistance of SKD 61 steel.However,the corrosion characteristics of the nitrocarburized compound layer was deteriorated by oxidation treatment.展开更多
Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of AISI 4140 steel. Plasma nitrocarburizing was conducted for 3 h at 570 ℃ in the nitrogen, hydrogen...Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of AISI 4140 steel. Plasma nitrocarburizing was conducted for 3 h at 570 ℃ in the nitrogen, hydrogen and methane atmosphere to produce the ε-Fe2-3(N,C) phase. It was found that the compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ′-Fe4(N,C) phase. The thickness of the compound layer was about 10 μm and the diffusion layer was about 300 μm in thickness, respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at a constant temperature of 500 ℃ for 1 h. The very thin magnetite (Fe3O4) layer 1-2 μm in thickness on top of the compound layer was obtained by plasma post oxidation. It was confirmed that the corrosion characteristics of the nitrocarburized compound layer can be further improved by the application of the superficial magnetite layer.展开更多
Background In clinical practice, the mechanisms underlying chronic post-surgical pain （CPSP） remain insufficiently understood. The primary goals of this study were to determine the incidence of chronic pain after th...Background In clinical practice, the mechanisms underlying chronic post-surgical pain （CPSP） remain insufficiently understood. The primary goals of this study were to determine the incidence of chronic pain after thoracic surgery and to identify possible risk factors associated with the development of chronic post-thoracotomy pain in Chinese patients. The secondary goal was to determine whether the difference between pre- and post-operative white blood cell （WBC） counts could predict the prevalence of CPSP after thoracotomy. The impact of chronic pain on daily life was also investigated. Methods We contacted by phone 607 patients who had undergone thoracotomy at our hospital during the period February 2009 to May 2010. Statistical comparisons were made between patients with or without CPSP. Results Results were ultimately analyzed from 466 qualified patients. The overall incidence of CPSP was 64.5%. Difference between pre- and post-operative WBC counts differed significantly between patients with or without CPSP （P 〈0.001） and was considered as an independent risk factor for the development of CPSP following thoracotomy （P 〈0.001）. Other predictive factors for chronic pain included younger age （〈60 years, P 〈0.001）, diabetes mellitus （P=0.023）, acute post-operative pain （P=0.005） and the duration of chest tube drainage （P 〈0.001）. At the time of interviews, the pain resulted in at least moderate restriction of daily activities in 15% of the patients, of which only 16 patients had paid a visit to the doctor and only three of them were satisfied with the therapeutic effects, Conclusions Chronic pain is common after thoracotomy. WBC count may be a new independent risk factoring surgical patients during peri-operative period. Besides, age, diabetes mellitus, acute post-operative pain, and duration of chest tube drainage may also play a role in chronic post-surgical pain occurrence.展开更多
文摘BACKGROUND： Cryoanalgesia at -50 ℃ for 90 seconds yields effective pain relief following thoracotomy. In China, -50 ℃ is a common temperature for intercostal cryoanalgesia following thoracotomy. However, experimental results vary. OBJECTIVE： To explore intercostal nerve pathological changes at -70 ℃ for various freezing times by studying canines, and to evaluate long-term clinical efficacy of intercostal nerve cryoanalgesia for postoperative pain relief based on the animal experiments. DESIGN, TIME AND SETTING： A comparative animal study was performed at the Animal Experimental Center of the General Hospital of the People＇s Liberation Army. Based on results from the animal study, a randomized, controlled, clinical trial was performed at the Department of Thoracic Surgery of the General Hospital of the People＇s Liberation Army between October 2006 and October 2008. PARTICIPANTS： A total of 120 patients undergoing posterolateral single incision Iobectomy at the Department of Thoracic Surgery of PLA General Hospital between October 2006 and October 2008 were selected. Nervous system diseases were excluded. METHODS： Animal experiment： 8 anaesthetized, mixed-breed dogs were used. The intercostal nerves （costal bone 6-10） were frozen at -70 ℃ for varying times （30, 60, 90, 120, and 180 seconds）. Clinical study： 120 patients were randomly assigned to 2 groups （n = 60）. In the cryoanalgesia group, the intercostal nerves were frozen prior to chest closure, and 4 costal nerves （1 at incision level, 2 above and below incision, and 1 at drainage tube level） were frozen for 90 seconds at-70 ℃, respectively. Intercostal nerves were not frozen in the control group patients. Dolantin was used to relieve postoperative pain in patients from both groups. MAIN OUTCOME MEASURES： Pathological changes in frozen intercostal nerves were examined at days 1, 10, 30, and 60 following freezing. Following surgery, the degree of postoperative pain in all patients was evaluated by visual analogue scale at days 1,3, 5, 9, 30, 60, 90, and 180. Dolantin doses at days 1, 3, 5, 9 post-surgery and postoperative complications were noted. RESULTS： Nerve damage progressively increased with length of freezing time at -70 ℃, and recovery time from damage was gradually increased. After freezing for 90 seconds, the nerves exhibited obvious histopathological damage, and then completely recovered. In addition, after freezing for 180 seconds, the histopathological changes in nerves were reversible. In the clinical study, visual analogue scale scores were significantly less in the cryoanalgesia group compared with the control group （P 〈 0.01）, which was maintained over 30 days. In the cryoanalgesia group, the mean dolantin dose administered and postoperative complications were significantly reduced compared with the control group （P 〈 0.01）. CONCLUSION： Freezing of the intercostal nerve at -70 ℃ for 90 seconds is a safe and long-term effective method for relieving post-thoracotomy pain.
文摘Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of SKD 61 steel.Plasma nitrocarburizing was conducted for 12 h at 540℃in the nitrogen, hydrogen and methane atmosphere to produce theε-Fe-（2-3）（N,C） phase.The compound layer produced by plasma nitrocarburising was predominantly composed ofε-phase,with a small proportion ofγ′-Fe-4 （N,C） phase. The thickness of the compound layer and the diffusion layer are about 10μm and about 200μm,respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at constant temperature of 500℃for 1 h.The very thin magnetite （Fe-3O-4） layer of 1-2μm in thickness on top of the compound layer was obtained.Anodic polarization test revealed that plasma nitrocarburizing process contributed a significant improvement of corrosion resistance of SKD 61 steel.However,the corrosion characteristics of the nitrocarburized compound layer was deteriorated by oxidation treatment.
文摘Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of AISI 4140 steel. Plasma nitrocarburizing was conducted for 3 h at 570 ℃ in the nitrogen, hydrogen and methane atmosphere to produce the ε-Fe2-3(N,C) phase. It was found that the compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ′-Fe4(N,C) phase. The thickness of the compound layer was about 10 μm and the diffusion layer was about 300 μm in thickness, respectively. Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at a constant temperature of 500 ℃ for 1 h. The very thin magnetite (Fe3O4) layer 1-2 μm in thickness on top of the compound layer was obtained by plasma post oxidation. It was confirmed that the corrosion characteristics of the nitrocarburized compound layer can be further improved by the application of the superficial magnetite layer.
文摘Background In clinical practice, the mechanisms underlying chronic post-surgical pain （CPSP） remain insufficiently understood. The primary goals of this study were to determine the incidence of chronic pain after thoracic surgery and to identify possible risk factors associated with the development of chronic post-thoracotomy pain in Chinese patients. The secondary goal was to determine whether the difference between pre- and post-operative white blood cell （WBC） counts could predict the prevalence of CPSP after thoracotomy. The impact of chronic pain on daily life was also investigated. Methods We contacted by phone 607 patients who had undergone thoracotomy at our hospital during the period February 2009 to May 2010. Statistical comparisons were made between patients with or without CPSP. Results Results were ultimately analyzed from 466 qualified patients. The overall incidence of CPSP was 64.5%. Difference between pre- and post-operative WBC counts differed significantly between patients with or without CPSP （P 〈0.001） and was considered as an independent risk factor for the development of CPSP following thoracotomy （P 〈0.001）. Other predictive factors for chronic pain included younger age （〈60 years, P 〈0.001）, diabetes mellitus （P=0.023）, acute post-operative pain （P=0.005） and the duration of chest tube drainage （P 〈0.001）. At the time of interviews, the pain resulted in at least moderate restriction of daily activities in 15% of the patients, of which only 16 patients had paid a visit to the doctor and only three of them were satisfied with the therapeutic effects, Conclusions Chronic pain is common after thoracotomy. WBC count may be a new independent risk factoring surgical patients during peri-operative period. Besides, age, diabetes mellitus, acute post-operative pain, and duration of chest tube drainage may also play a role in chronic post-surgical pain occurrence.
