Objective:To provide basis for preventing flight safety accidents caused by hypoxia by exploring the subjective and objective performance of pilots in hypobaric hypoxia environment.Methods:The relevant data of pilots′ high altitude physiological training were retrospectively analyzed and a symptom questionnaire upon the training were summarized. The pilots were divided into excellent group (time of useful consciousness >6 min), good group (3 min ≤time of useful consciousness <6 min) and qualified group (2 min ≤time of useful consciousness <3 min) according to the time of useful consciousness. The hypoxia symptoms and physiological parameters of pilots in each group were statistically analyzed.Results:A total of 919 pilots were included, in which 416 were in excellent group, 490 were in good group and 13 were in qualified group. Among the 25 hypoxia symptoms, there were significant differences in the components of numbness and difficulty in calculation among 3 groups ( χ2=6.04, 7.79, P=0.049, 0.020), but there were no significant differences in the components of the other 23 hypoxia symptoms (all P>0.05). The changes of blood oxygen saturation were significant in group main effect, time main effect and their interaction ( F=25.65, 1 039.77, 25.22, all P<0.001). The change of heart rate was statistically significant in the main effect of time ( F=66.41, P<0.001) but in time main effect and their interaction (both P>0.05). There was no significant difference in respiratory rate among group main effect, time main effect and their interaction (all P>0.05). The distribution and variation of blood oxygen saturation were statistically significant differences among the 3 groups in the ranges of 81%-90%, 71%-80% and 65%-70% ( H=125.93, 372.83, 13.10, all P≤0.001) unlike the range of 91%-100% ( H=2.48, P=0.289). Conclusions:The excellent group showed better blood oxygen saturation maintaining and useful consciousness time enduring capabilities, and those imply them in better performance and consciousness that enable the operation in hypoxic environment with more ease.

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 basis for preventing flight safety accidents caused by hypoxia by exploring the subjective and objective performance of pilots in hypobaric hypoxia environment.Methods:The relevant data of pilots′ high altitude physiological training were retrospectively analyzed and a symptom questionnaire upon the training were summarized. The pilots were divided into excellent group (time of useful consciousness >6 min), good group (3 min ≤time of useful consciousness <6 min) and qualified group (2 min ≤time of useful consciousness <3 min) according to the time of useful consciousness. The hypoxia symptoms and physiological parameters of pilots in each group were statistically analyzed.Results:A total of 919 pilots were included, in which 416 were in excellent group, 490 were in good group and 13 were in qualified group. Among the 25 hypoxia symptoms, there were significant differences in the components of numbness and difficulty in calculation among 3 groups ( χ2=6.04, 7.79, P=0.049, 0.020), but there were no significant differences in the components of the other 23 hypoxia symptoms (all P>0.05). The changes of blood oxygen saturation were significant in group main effect, time main effect and their interaction ( F=25.65, 1 039.77, 25.22, all P<0.001). The change of heart rate was statistically significant in the main effect of time ( F=66.41, P<0.001) but in time main effect and their interaction (both P>0.05). There was no significant difference in respiratory rate among group main effect, time main effect and their interaction (all P>0.05). The distribution and variation of blood oxygen saturation were statistically significant differences among the 3 groups in the ranges of 81%-90%, 71%-80% and 65%-70% ( H=125.93, 372.83, 13.10, all P≤0.001) unlike the range of 91%-100% ( H=2.48, P=0.289). Conclusions:The excellent group showed better blood oxygen saturation maintaining and useful consciousness time enduring capabilities, and those imply them in better performance and consciousness that enable the operation in hypoxic environment with more ease.

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 investigate the epidemiological characteristics of rabies-exposed populations in Anji County, Zhejiang Province from 2017 to 2021, so as to provide insights into rabies control in the county. Methods: All data pertaining to rabies were captured from Monthly Report of Rabies-exposed Populations in Huzhou City and Investigation Form of Multiple Dog Injuries reported by dog injury clinics in Anji County from 2017 to 2021, and the species of animals causing dog injuries, duration, degree and site of exposure, and post-exposure treatment of rabies-exposed populations were descriptively analyzed. Results: Totally 46 186 cases with rabies exposure were reported in dog injury clinics in Anji County from 2017 to 2021, and the rate of exposure appeared a tendency towards a decline year by year (Z=-23.249, P<0.001), with an annual mean exposure rate of 1 739.59/105. The number of cases with exposure to rabies peaked in July and August (10 066 cases, 21.79%). Dogs were predominant animals causing injuries (31 732 cases, 68.70%), and the rate of exposure to dog bites appeared a tendency towards a decline year by year (Z=-35.541, P<0.001). There were 11 350 cases with cat-causing injuries (24.57%), and the rate of exposure to cat bites appeared a tendency towards a rise (Z=14.834, P<0.001). Lower extremity was the main site of exposure (22 364 cases, 48.42%), and the proportions of grade Ⅱ and Ⅲ exposure to rabies were 72.85% and 25.23%, the rates of exposure both appeared a tendency towards a decline (Z=-14.522, P<0.001; Z=-21.820, P<0.001). The proportion of using human rabies immune globulin was 25.72% among populations with grade Ⅲ exposure, which appeared a tendency towards a rise (Z=6.636, P<0.001). Conclusions The rate of exposure to rabies appeared a tendency towards a decline in Anji County from 2017 to 2021. Dogs were predominant animals causing injuries, and the rate of cat bites appeared a tendency towards a rise from 2017 to 2021; however, the proportion of using human rabies immune globulin remains to be improved among populations with grade Ⅲ exposure.

Non-surgical treatment programs play an essential position among hepatocellular carcinoma therapies. Precise evaluation of treatment efficacy has significant value in determination of non-surgical treatment programs for hepatocellular carcinoma. As the treatment methodologies and philosophy progress, the evaluation standards for the efficacy of non-surgical treatment of hepatocellular carcinoma are constantly updated and developed. This paper generalizes the development process of the evaluation criteria for the efficacy of non-surgical treatment of hepatocellular carcinoma, summarizes the evaluation criteria that have been and are currently applied in the clinical field in general, in order to provide a basis for patients to obtain timely and effective evaluation and treatment, and gives an outlook on the future development of the evaluation standards.

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 compare the ear baric function between 4000m altitude chamber test with inhaling air and 6900m altitude chamber test with inhaling pure oxygen.Methods Eleven healthy male volunteers attended two tests as two groups by self-comparison. As the air group the volunteers inhaled air at 4000m, while as the pure oxygen group they inhaled pure oxygen at 6900m altitude, and the time interval between the two tests was more than two weeks. During the test, the volunteers breathed air or pure oxygen at random for 1h, and then were exposed at a speed of 20m/s to the target altitude for 5min. Hereafter they were sent back to the ground at the same speed. The changes of subjective symptoms, degree of tympanic congestion, acoustic immitance index and pure-tone auditory threshold were recorded before and after the test. The acoustic impedance index and pure-tone threshold were statistically analyzed.ResultsFour volunteers (4 ears) in air group and 7 volunteers (7 ears) in pure oxygen group reported ear pain in altitude chamber exposures, respectively. The pain-triggering altitude was higher in the pure oxygen group. Immediately after tests, there were 3 (3 ears) and 5 volunteers (5 ears) with Ⅲ degree congestion of the tympanic membrane in the two groups respectively. Four volunteers (6 ears) developed gradually aggravated hemorrhages after altitude exposure. And the tympanic membrane congestion difference between groups was statistically significant at 3 and 24h after tests (P<0.01). The type A tympanogram appeared in 11 (15 ears) and 11 (14 ears) volunteers respectively immediately after tests. The increase of static compliance value was significantly greater in pure oxygen group than in air group immediately after tests (P<0.05), the decrease of middle ear pressure was more significant in pure oxygen group than in air group at 3 and 24h after tests (P<0.05). Both the two altitude exposure tests resulted in eustachian tube dysfunction. At 3 and 24h after the tests, the increase of individual frequency pure-tone threshold was significantly higher in pure oxygen group than in air group (P<0.05).Conclusion Breathing pure oxygen and lifting height could increase the screening degree of ear baric function test in hypobaric chamber, and have greater influence on degree of tympanic congestion, acoustic immittance and pure-tone auditory threshold in 24 hours.

10 male subjects participated in the environmental simulation study to evaluate the operation ergonomics at high-temperature in the cockpit. Grip strength, perception, dexterity, reaction and intelligence were measured respectively during the tests at 40 degrees C and 45 degrees C, simulating the high-temperatures in a simulation cockpit chamber. Then the data obtained were compared to the combined index of heat stress (CIHS). The average values of each item of the subjects' performance at the two different temperatures are compared. The results indicated that CIHS exceeded the heat stress safety line after 45 min at 40 degrees C, grip strength decreased by 12%, and perception increased by 2.89 times. In contrast, at 45 degrees C, CIHS exceeded the safety line after 20 min, grip strength decreased by 3.2%, and perception increased by 4.36 times. However, Finger dexterity was less affected. Reaction ability was first accelerated, and then slowed down. The error rate in the intelligence test increased to a greater extent. At the high temperatures, the minimum perception was the most affected, followed by grip strength, reaction and finger dexterity were less affected, while the intelligence did not decline, but rise.
Adult ; Aerospace Medicine ; Aircraft ; Computer Simulation ; Ergonomics ; Heat Stress Disorders ; physiopathology ; Hot Temperature ; adverse effects ; Humans ; Male ; Young Adult