Objective:To develop and evaluate the efficacy and safety of a three-dimensional (3D) digestive endoscope for gastric endoscopic submucosal dissection (ESD) through animal experiments.Methods:Two Dutch pigs were utilized from the Zhengzhou University Animal Experiment Center for the study. ESD procedures were performed by two senior endoscopists, one using 3D glasses and the other utilizing a 3D high-definition head display. The success of ESD was assessed based on predefined criteria, including completion of surgical steps, complete detachment of the presumptive lesion, and effective bleeding control during and after the surgery. The number of successful procedures and incidences of perforation were recorded. The stereoscopic experience of the endoscopists, including both the primary endoscopist and the assistant, was also evaluated. Furthermore, the assessment encompassed any reported symptoms of eye discomfort, such as eye fatigue, ocular pain, and blurred vision. Additionally, the confidence level of the endoscopists in the mechanical aspects of the operation, as well as encountered issues during the endoscopic procedures, were documented.Results:Two ESD were successful and no perforation occurred. Feedback from endoscopists suggested that 3D digestive endoscopy offered clear images with enhanced three-dimensionality during surgery, clear sense of distance and layering, allowing for a precise judgment of bleeding points, which surpassed 2D capabilities. No eye discomfort was experienced by endoscopists or assistants during or after the procedures. While endoscopists exhibited high confidence in 3D digestive endoscopy, they noted issues with image blurring when the camera was positioned less than 10 mm from the gastrointestinal tract wall.Conclusion:Preliminary results show that 3D digestive endoscopes can provide excellent stereo imaging, improved positioning accuracy, and safety during live animal stomach ESD procedures, without significantly increasing endoscopists' eye discomfort. Nevertheless, efforts are needed to address image blurring concerns when the camera is close to the gastrointestinal tract wall.

Objective:To provide scientific basis for pilots′ hypoxia training by comparing and analyzing the effects of hypoxia training under normobaric and hypobaric environments.Methods:Forty-two healthy subjects were selected. The pilot reduced oxygen breathing device and hypobaric chamber were used to simulate 7 500 m hypoxia training, and blood oxygen saturation, heart rate, respiratory rate and hypoxia endurance time were monitored and recorded. The hypoxia symptom questionnaire was filled out by the subjects after 2 training sessions. The hypoxia endurance time and hypoxia tolerance grade of normobaric and hypobaric hypoxia training were analyzed, and the differences of blood oxygen saturation and hypoxia symptoms were compared between 2 hypoxia trainings.Results:Forty-two subjects completed the normobaric and hypobaric hypoxia trainings. The survival curve analysis of hypoxia endurance time showed that the median hypoxia endurance time of normobaric and hypobaric hypoxia training was [3.17(2.70, 3.64)] min and [3.67(3.46, 3.88)] min respectively, with no significant difference ( P>0.05). There was no significant difference in the grade distribution of hypoxia tolerance between 2 hypoxia trainings ( P>0.05). The blood oxygen saturation curves of 2 hypoxia trainings were basically consistent. There was no significant difference between 2 hypoxia trainings on blood oxygen saturation, heart rate and respiratory rate (all P>0.05). There were significant differences in difficulty in calculation, difficulty in concentration and with palpitation ( χ2=4.81, 3.97, 3.98, P=0.028, 0.046, 0.046). Conclusions:The analysis showed that most physiological responses and subjective symptoms of pilots are quite similar in the normobaric and hypobaric hypoxia training at simulated 7 500 m. Both normobaric and hypobaric exposures show the similar hypoxia training effect.

Objective:To provide scientific basis for pilots′ hypoxia training by comparing and analyzing the effects of hypoxia training under normobaric and hypobaric environments.Methods:Forty-two healthy subjects were selected. The pilot reduced oxygen breathing device and hypobaric chamber were used to simulate 7 500 m hypoxia training, and blood oxygen saturation, heart rate, respiratory rate and hypoxia endurance time were monitored and recorded. The hypoxia symptom questionnaire was filled out by the subjects after 2 training sessions. The hypoxia endurance time and hypoxia tolerance grade of normobaric and hypobaric hypoxia training were analyzed, and the differences of blood oxygen saturation and hypoxia symptoms were compared between 2 hypoxia trainings.Results:Forty-two subjects completed the normobaric and hypobaric hypoxia trainings. The survival curve analysis of hypoxia endurance time showed that the median hypoxia endurance time of normobaric and hypobaric hypoxia training was [3.17(2.70, 3.64)] min and [3.67(3.46, 3.88)] min respectively, with no significant difference ( P>0.05). There was no significant difference in the grade distribution of hypoxia tolerance between 2 hypoxia trainings ( P>0.05). The blood oxygen saturation curves of 2 hypoxia trainings were basically consistent. There was no significant difference between 2 hypoxia trainings on blood oxygen saturation, heart rate and respiratory rate (all P>0.05). There were significant differences in difficulty in calculation, difficulty in concentration and with palpitation ( χ2=4.81, 3.97, 3.98, P=0.028, 0.046, 0.046). Conclusions:The analysis showed that most physiological responses and subjective symptoms of pilots are quite similar in the normobaric and hypobaric hypoxia training at simulated 7 500 m. Both normobaric and hypobaric exposures show the similar hypoxia training effect.

Objective:To study the simplified oxygen supply protection scheme below 15.0 km, and to evaluate its protection performance through tests.Methods:The parameter of YX-5 oxygen system was modified, by reducing its total oxygen supply pressure and closing a large number of oxygen supply mechanisms, and compensatory suit was cancelled. A dummy and 4 volunteers with helmet and oxygen mask using modified YX-5 oxygen system underwent 5 tests in hypobaric chamber, included ① normal oxygen supply performance test at 0-10.0 km; ② pure oxygen supply performance test at 0-10.0 km; ③ positive pressure supplying oxygen performance test at 13.0, 15.0, 16.0 km; ④ impact test of pressured oxygen supply; ⑤ pressured oxygen supplying performance physiological test at 15.0 km.Results:Under the normal oxygen supply, the oxygen pressure of modified YX-5 oxygen system below 12.0 km was >21.0 kPa. When high-altitude pressurized oxygen supply was used, the oxygen pressure was >15.8 kPa at 12.0-15.0 km. Inspiration resistance of modified YX-5 oxygen system was <0.34 kPa when the dummy′s respiration ventilation rate was 20 L/min. The impact pressure of mask was 1.25 kPa when pressured oxygen supply switched on but without compensatory suit connected to modified YX-5 oxygen system. Four volunteers completed the human physiological test up to 15.0 km high-altitude pressurized oxygen supply to verify the protective performance of the scheme, and they had no adverse physiological reactions after the test.Conclusions:The simplified protection scheme can provide protection against hypoxia for pilots at 0-15.0 km altitude.

Objective:To evaluate the protection performance of military transport aircraft oxygen system for aircrew and provide the physiological tests basis for product design finalization.Methods:Four dummies and 4 healthy volunteers who were equipped with individual protection equipment and military transport aircraft oxygen system completed 4 tests in altitude chamber including the oxygen supply performance physical test of oxygen system, the rapid decompression physical test of oxygen system, the physiological tests of oxygen continuously supplying for 6 h and oxygen supply performance test in rapid decompression at 12.0 km. Oxygen concentration, respiratory resistance, safety pressure, peak value, peak duration and steady pressure of mask under rapid decompression were tested. Electrocardiograph and oxygen saturation of volunteers were monitored.Results:The oxygen partial pressure provided by military transport aircraft oxygen system under 12.0 km was ≥19.1 kPa corresponding to the respiration ventilation volume of 20 L/min of dummy. The expiratory resistance was no higher than 441.3 Pa and the inspiration resistance was no higher than 490.3 Pa before the safety pressure connected. The peak pressure value in rapid decompression with 1.0 L lung volume of dummy was no higher than 5.8 kPa. The oxygen partial pressure provided by military transport aircraft oxygen system for volunteers was over 21.9 kPa in the 6 h cruising flight. All 4 volunteers successfully completed the rapid decompression physiological tests at 12.0 km with good subjective and objective responses.Conclusions:The protection performance of military transport aircraft oxygen system for aircrew can provide enough protection against the hypoxia up to 12.0 km

Objective:To evaluate the protection performance of military transport aircraft oxygen system for aircrew and provide the physiological tests basis for product design finalization.Methods:Four dummies and 4 healthy volunteers who were equipped with individual protection equipment and military transport aircraft oxygen system completed 4 tests in altitude chamber including the oxygen supply performance physical test of oxygen system, the rapid decompression physical test of oxygen system, the physiological tests of oxygen continuously supplying for 6 h and oxygen supply performance test in rapid decompression at 12.0 km. Oxygen concentration, respiratory resistance, safety pressure, peak value, peak duration and steady pressure of mask under rapid decompression were tested. Electrocardiograph and oxygen saturation of volunteers were monitored.Results:The oxygen partial pressure provided by military transport aircraft oxygen system under 12.0 km was ≥19.1 kPa corresponding to the respiration ventilation volume of 20 L/min of dummy. The expiratory resistance was no higher than 441.3 Pa and the inspiration resistance was no higher than 490.3 Pa before the safety pressure connected. The peak pressure value in rapid decompression with 1.0 L lung volume of dummy was no higher than 5.8 kPa. The oxygen partial pressure provided by military transport aircraft oxygen system for volunteers was over 21.9 kPa in the 6 h cruising flight. All 4 volunteers successfully completed the rapid decompression physiological tests at 12.0 km with good subjective and objective responses.Conclusions:The protection performance of military transport aircraft oxygen system for aircrew can provide enough protection against the hypoxia up to 12.0 km

Objective:To study the simplified oxygen supply protection scheme below 15.0 km, and to evaluate its protection performance through tests.Methods:The parameter of YX-5 oxygen system was modified, by reducing its total oxygen supply pressure and closing a large number of oxygen supply mechanisms, and compensatory suit was cancelled. A dummy and 4 volunteers with helmet and oxygen mask using modified YX-5 oxygen system underwent 5 tests in hypobaric chamber, included ① normal oxygen supply performance test at 0-10.0 km; ② pure oxygen supply performance test at 0-10.0 km; ③ positive pressure supplying oxygen performance test at 13.0, 15.0, 16.0 km; ④ impact test of pressured oxygen supply; ⑤ pressured oxygen supplying performance physiological test at 15.0 km.Results:Under the normal oxygen supply, the oxygen pressure of modified YX-5 oxygen system below 12.0 km was >21.0 kPa. When high-altitude pressurized oxygen supply was used, the oxygen pressure was >15.8 kPa at 12.0-15.0 km. Inspiration resistance of modified YX-5 oxygen system was <0.34 kPa when the dummy′s respiration ventilation rate was 20 L/min. The impact pressure of mask was 1.25 kPa when pressured oxygen supply switched on but without compensatory suit connected to modified YX-5 oxygen system. Four volunteers completed the human physiological test up to 15.0 km high-altitude pressurized oxygen supply to verify the protective performance of the scheme, and they had no adverse physiological reactions after the test.Conclusions:The simplified protection scheme can provide protection against hypoxia for pilots at 0-15.0 km altitude.

Objective:To evaluate the effects of wearing N95 mask on the quality of chest compression and fatigue.Methods:A total of 80 participants from Zhongnan Hospital with basic life support (BLS) certification conferred by American Heart Association (AHA) within two years were enrolled. After reviewing the key points of cardiopulmonary resuscitation (CPR) and grasping the operation on the manikin, they were randomized (random number) into two groups: wearing surgical masks (SM group, n=40) and wearing N95 masks (N95 group, n=40) during CPR. Each participant performed a 2-minute chest compression-only CPR on the manikin. Participants' height, body weight, Borg scores and physiological parameters before and after CPR were recorded. The quality of chest compression (including compression depth, compression rate, adequate depth proportions, adequate rate proportions, hand position and complete chest recoil) were recorded by Laerdal QCPR ? software. Student's t test and Mann-Whitney test were used to compare the differences of chest compression quality indexes between the two groups. Results:Compared with the SM group, participants in the N95 group had significantly increased median of Borg scores after CPR (16 vs 14, P=0.027), and decreased quality of chest compression, including the decline in compression depth (mean 47 mm vs 52 mm, P=0.020), compression rate (107 times/min vs 118 times/min, P=0.004), complete chest recoil rate (89.8% vs 98.1%, P=0.046), adequate depth proportions (67.4% vs 89.6%, P<0.01) and adequate rate proportions (60.6% vs 74.8%, P<0.01). Conclusions:Wearing N95 masks during CPR decreases the quality of chest compression and aggravates rescuers’ fatigue. Therefore, it is necessary to exchange rescuers more frequently to ensure the quality of chest compression when wearing N95 masks.

More and more studies have found that red blood cell distribution width (RDW) can be used for acute pancreatitis (AP) classification, dynamic monitoring and evaluation of disease severity, mortality, prognosis and complication. Some inflammatory markers, such as procalcitonin (PCT), C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR) and pancreatitis scoring system are also associated with severity of AP, and can further improve the evaluation of AP severity when combined with RDW. This article reviewed the RDW and classification of AP, the dynamic changes of RDW and AP, RDW combined with inflammatory indices for prediction of severity of AP, and RDW combined with pancreatitis scoring system for prediction of severity of AP, so as to improve the understanding of predictive value of RDW in assessing the severity of AP.

Objective:To summarize the patient profiles and therapeutic efficacies of ABO-incompatible living-related kidney transplantations at 19 domestic transplant centers and provide rationales for clinical application of ABOi-KT.Methods:Clinical cases of ABO-incompatible/compatible kidney transplantation (ABOi-KT/ABOc-KT) from December 2006 to December 2009 were collected. Then, statistical analyses were conducted from the aspects of tissue matching, perioperative managements, complications and survival rates of renal allograft or recipients.Results:Clinical data of 342 ABOi-KT and 779 ABOc-KT indicated that (1) no inter-group differences existed in age, body mass index (BMI), donor-recipient relationship or waiting time of pre-operative dialysis; (2) ABO blood type: blood type O recipients had the longest waiting list and transplantations from blood type A to blood type O accounted for the largest proportion; (3) HLA matching: no statistical significance existed in mismatch rate or positive rate of PRA I/II between two types of surgery; (4) CD20 should be properly used on the basis of different phrases; (5) hemorrhage was a common complication during an early postoperative period and microthrombosis appeared later; (6) no difference existed in postoperative incidence of complications or survival rate of renal allograft and recipients at 1/3/5/10 years between ABOi-KT and ABOc-KT. The acute rejection rate and serum creatinine levels of ABOi-KT recipients were comparable to those of ABOc-KT recipients within 1 year.Conclusions:ABOi-KT is both safe and effective so that it may be applied at all transplant centers as needed.