[Preliminary report on partial pressure changes of oxygen and carbon dioxide in umbilical artery and vein before and after the first breath in Chinese neonates II-The personalized analysis of partial pressure of oxygen and carbon dioxide difference between umbilical artery and vein at same time in same newborn].

Objective: In order to explore the mechanism of neonatal spontaneous breathing, the difference of oxygen and carbon dioxide between umbilical cord arteries and veins before the start of spontaneous breathing after birth has been analyzed among people. In this part, the related information is analyzed individually. Methods: After all fetal parents signed the informed consent before birth, and before the newborn was born and did not breathe, the umbilical cord was exposed as quickly as possible, and the heparinized arterial indwelling needle was inserted into the umbilical artery and umbilical vein in the direction of newborn and placenta, and then blood was taken continuously. Although dozens of mothers were selected,but only 3 cases were collected from Pua and Puv blood samplers at the same time for blood gas analysis and determination, and the differences and dynamic changes of umbilical vein and umbilical artery were calculated and analyzed. Results: In all 3 none spontaneous breathing newborns,PuvO2 was significantly higher than PuaO2 at the same time (P<0.01), with an average difference of (24.17±7.09) mmHg; while PuvCO2 was significantly lower than PuaCO2 (all P<0.01), with an average difference of (-7.67±3.70) mmHg.The difference of Puv-uaO2 was significantly higher than those of Puv-uaCO2 (P<0.05). Conclusion: PuaO2 decreases gradually with time (heartbeat frequency) before spontaneous breathing after the delivered fetus as a newborn, and it induces the first inhalation to start spontaneous breathing when it reaches the threshold of triggering breathing.

[The effectiveness of different respiration models to the amplitude of waveform information in arterial blood gas].

Objective: The objective is to find the characteristics of arterial blood sample waveform in different respiration models. Methods: Six post-operative patients with normal heart function and negative Allen test, were 4 male and 2 female, (59.00±16.64)year, (71.67±0.37)kg, left ventricular ejection fraction(LVEF) (61.33±2.16)%, had been placed the arterial catheterization and central venous catheterization for continuous collecting arterial in 3 different kinds of respiration models: normal breathing, no breathing and deep breathing. We selected two breaths cycles of waveform from each patient for data calculations of magnitudes and time interval. Compare the adjacent highest and lowest values of patients to verify whether there are periodic wave-like signal changes in arterial and venous blood gas in the three breathing states. In addition, statistical t-test analysis was performed on the change amplitude of the periodic wave-like signal of the patient's arterial and venous blood gas to compare whether there is a difference. Results: The heart beat numbers for drawing blood into pipe were 15-16, and all covered more than 2 breathing cycles. There were significant changes of arterial PaO2 (i.e. the highest high values compare to the next lowest values, P<0.05) in three different breathing models(normal, no breathing and high breathing), the magnitudes of which were (9.96±5.18)mmHg, (5.33±1.55)mmHg and (13.13±7.55)mmHg, with (8.09±2.43)%, (5.29±2.19)% and (10.40±2.68)% from their mean respectively. PO2 in venous blood gas did not show wavy changes under normal breathing, 20 s breath holding and high tidal volume ventilation. The amplitudes were (1.63 ± 0.41) mmHg, (1.13 ± 0.41) mmHg and (1.31 ± 0.67) mmHg, which were (3.91 ± 1.22)%, (2.92 ± 1.12)%, (3.33 ± 1.81)%, respectively, which were significantly lower than that of arterial blood gas under the same state, but there was no significant difference between groups. Conclusion: With continuous beat-by-beat arterial blood sampling and ABG analyzing method in three different breathing models, We obtain a clear evidence of the biggest periodic parameters ABG waveform in high breathing models, which followed by normal breathing models, no breathing was the smallest, and the wave variation amplitude of venous oxygen partial pressure was not obvious in the three respiratory states, which implies the oscillatory information of the arterial blood with comes from the gas exchanging in the lung.

[Preliminary report on partial pressure changes of oxygen and carbon dioxide in umbilical artery and vein before and after the first breath in Chinese neonates I-The group difference of partial pressure of oxygen and carbon dioxide between umbilical artery and vein in newborns].

Objective: The fetus has no actual respiration, and the newborn begins to breathe after birth. We assume that the first breath dominantly generated by hypoxia. In this study, the changes and lowest limit of blood oxygen partial pressureof umbilical artery (PuaO2) after chemoreceptor were analyzed to explore the mechanism of neonatal spontaneous breathing. Methods: With signed consent form by all fetal parents before birth, 14 newborns successfully completed the umbilical artery or vein catheterization and drawn blood according to the heartbeat. All blood samples analyzed by blood gas analyzer,calculated and analyzed the similarities and differences between umbilical vein(Puv) and umbilical artery(Pua). Results: Although we completed 14 newborns, there were only 9 cases of umbilical artery samples and 8 cases of umbilical vein samples were collected. Only 3 cases collected both Pua and Puv blood samples at the same time (see serial paper II). PuaO2 in gradually decreased with time (heartbeat frequency), until Pua contracted after spontaneous breathing produced about 8~10 heartbeats, and then could not get enough blood samples. Only 3 newborns were able to take blood samples after spontaneous breathing for 8~10 heartbeats, and their PuaO2 were jumped to 186.0, 137.0 and 93.8 mmHg respectively. The mean value of PuaO2 was (25.94±6.79, 18.04~37.51)mmHg, the highest value was (29.11±6.46, 23.00~45.90)mmHg, and the lowest value was (21.34±5.54, 14.00~33.60)mmHg. Although PuvO2 decreased gradually with time (heartbeat) too, most of them also showed the tendency of alternately rising and falling with the regularity of mother's respiration. The mean value of PuvO2 was (53.35±21.35, 32.56~100.73)mmHg, the highest value was (90.38±48.44, 43.40~153.00)mmHg, and the lowest value was (36.96±14.90, 24.80~73.80)mmHg. Although there were large individual differences, the mean, highest and lowest values of PuvO2 were significantly higher than those of PuaO2 (P<0.05); although PuvCO2 slightly lower than PuaCO2, it was no significant difference (P>0.05). Conclusion: PuaO2 decreases gradually with time before spontaneous breathing after the delivered fetus as a newborn, and it induces the first inhalation to start spontaneous breathing when it reaches the threshold of triggering breathing.

[The experimental evidence of waveform information in arterial blood gas by beat-by-beat sampling method in human body-the differences of waveform information between arterial and venous blood samples].

Objective: The arterial blood with the oscillatory information comes from the right heart system after gas exchanging in the lung. However, the evidence of the waveform of venous ABG is lack. The objectives of this article are to compare the different information between arterial and venous beat-by-beat blood sample at the same time. Methods: Six post-operative patients with normal heart function and negative Allen test, had been placed the arterial catheterization and central venous catheterization directly connected to pre-heparin plasticpipes for continuous collecting arterial and venous blood. We twisted the 2 pipes into helix formation. After drawing arterial and venous blood with syringes in one heart beat with one helix at the same time, totally 15 heart beats, clipping the pipes with forceps, we put the helix pipe into icedwater at once and analyses PaO2, PaCO2, pH and SaO2 as soon as possible. We selected two breathscycles of waveform from each patient for data calculations of magnitudes and time interval. Results: The heart beat numbers for drawing blood into pipe were 15~16, and all covered more than 2 breathing cycles. There were significant changes of arterial PaO2(i.e. the highest high values compare to the next lowestvalues, P<0.05), but no significant changes in venous blood(P>0.05). The magnitudes of changing PaO2 in arterial and venous blood sample were (9.96±5.18)mmHg and (1.63±0.41)mmHg with significant variance(P=0.010), and they were (8.09±2.43)% and (3.91±1.22)%from their mean with significant variance(P=0.009) respectively. Conclusion: With continuous beat-by-beat arterial and venous blood sampling and ABG analyzing method at the same time, we obtain a clear evidence of periodic parameters ABG waveform, which following breathing cycle, but no clear ABG waveform of the periodic parameters in the venous blood samples, which implies the oscillatory information of the arterial blood with comes from the gas exchanging in the lung.

[Preliminary experimental study on the influence of different tidal volume and frequency of normal minute ventilation on the dynamic changes of carotid blood oxygen in living goats].

Objective: On the basis of preliminarily verifying the use of ultra-fast reaction polymer matrix optical fiber oxygen sensor and its measuring system to record the continuous and dynamic changes of carotid artery oxygen partial pressure (PaO2), in order to analyze and discuss the influence of lung ventilation on the continuous and dynamic changes of PaO2, we designed a whole animal experimental study in vivo. Methods: Four hybrid goats were selected, and the skin was cut and exposed directly under general anesthesia and tracheal intubation. The oxygen sensor, connected with the measuring system, was inserted directly into the left carotid artery to continuously record the dynamic changes of PaO2. With normal minute ventilation,mechanical ventilation is implemented through three tidal volumes: normal tidal volume (VT=15 ml/kg, Rf=20 bpm), half tidal volume (halved VT, doubled Rf) and double tidal volume (doubled VT, halved Rf). Each tidal volume was stable for 10~15 min respectively. We analyzed and calculated the average values of PaO2, the fluctuation magnitudes of PaO2 changes between breaths of last 180 s and the delay times of lung-carotid artery were. We analyzed the effects of different tidal volumes. Results: The heart rate and blood pressure of living goats were maintained stable during the mechanical ventilation experiment with normal ventilation volume Lung-carotid artery delay time is 1.4~1.8 s (about 3 heartbeats at this time). Under normal tidal volume of mechanical ventilation, the average value of PaO2 was (102.94±2.40, 99.38~106.16) mmHg, and the fluctuation range was (21.43±1.65, 19.21~23.59) mmHg, accounting for (20.80± 1.34, 18.65~22.22)% of the average value. Under the condition of halving tidal volume, the average value of PaO2 was maintained at (101.01±4.25, 94.09~105.66) mmHg, which was slightly decreased but not significant (P>0.05 compared with normal mechanical ventilation), but the fluctuation range of PaO2 was significantly reduced to (18.14±1.43, 16.46~20.05) mmHg, accounting for 17.5% of the average value. Under double tidal volume mechanical ventilation, although the average value of PaO2 increased slightly remained at (106.42±4.74, 101.19~114.08) mmHg (P>0.05 compared with normal mechanical ventilation and P<0.05 compared with half tidal volume mechanical ventilation), the fluctuation magnitude of PaO2 increased significantly to (26.58±1.88, 23.46~28.46)mmHg. Conclusion: Inspiration and expiration of normal lung ventilation are the initial factors for the increase and decrease of PaO2 in carotid artery. Under normal ventilation, halving tidal volume and doubling tidal volume significantly changed the fluctuation magnitude of PaO2, but the average value of PaO2 changed only slightly, while the lung-carotid delay time was similar.

[Primary clinical investigation of cardiopulmonary exercise gas exchange in pulmonary hypertension patients with and without right-to-left shunt].

Objective: The aim of this study is to determine the changes of gas exchange parameters during ramp incremental cardiopulmonary exercise test (CPET) in patients with pulmonary hypertension (PH) could identify the right to left shunt (R-L Shunt). Methods: We did a retrospective analysis of exercise gas exchange parameters for 73 PH patients and 14 normal subjects as control, in Fuwai Hospital from October 2016 to August 2017, who did CPET with signature on content form. The gas exchange data of CPET were double-blindly independently interpreted by four export-doctors. According to the reading results of CPET, the PH patients were divided into four groups: ① R-L shunt positive group, ② R-L shunt suspicious group, ③R-L shunt negative group, ④late open R-L Shunt positive group. Results: Minute ventilation (VE), ventilatory equivalents for carbon dioxide and oxygen (VE/VCO2, VE/VO2), end-tidal partial pressure of oxygen (PETO2)in R-L shunt positive group were significantly increased ((7.36 ± 2.72) L/min, (1.84± 3.59), (5.02 ±4.34), (3.75±2.64) mmHg) at the beginning of exercise, and were also significantly higher than the control ((4.26 ± 2.59) L/min, (2.22± 2.08), (1.46 ±4.68), (3.96 ± 2.82) mmHg); Partial pressure of carbon dioxide in end expiratory gas (PETCO2) was decreased (-1.63 ±1.66) mmHg, and was significantly lower than control (2.22 ± 2.08) mmHg (P<0.01). Respiratory quotient (RER), carbon dioxide, VE/VCO2, VE/VO2, PETO2 in late open R-L Shunt positive group were suddenly increased ((0.40 ± 0.08), (11.07 ± 5.60),(30.55 ±7.89), (13.72 ±2.21) mmHg) at the end of exercise near the peak, significantly higher than control too ((0.38± 0.12), (5.67± 4.60), (4.54 ± 3.83), (5.51± 4.24) mmHg); PETCO2 was suddenly decreased at the end of the exercise compared to the resting stage (-6.82 ± 1.96) mmHg, and was significantly different from the control (5.67 ±4.60) mmHg. Carbon dioxide ventilatory efficiency, oxygen uptake ventilatory efficiency relative to the peak power (-8.38 ±3.24, -13.14 ± 6.47) at the recovery stage in late open R-L shunt positive group are significantly lower than control (6.22 ±2.87, 16.56± 4.20) (P<0.01). Conclusion: Cardiopulmonary function and ventilation efficiency of patients withpulmonary hypertension are significantly decreased; pulmonary hypertension and right to left shunt in patients not only resting ventilation efficiency is limited more serious; The characteristics of R-L shunt are the sudden increase of PETO2, VE/ VCO2, VE, RER and sudden decrease of PETCO2 and VO2/ VE at the beginning of exercise, and commonly companied with decreased SpO2. For the delay open R-L shunt, these changes occurred near the peak exercise rather than the beginning, and these characteristic changes quickly reversed after stopping exercise.

[Ultra-fast response polymer optical fiber oxygen measurement device and its preliminary experimental report on continuous dynamic change of arterial oxygen partial pressure under mechanical ventilation in living animals].

Objective: We tried to implant the ultra-fast polymer optical fiber chemical oxygen sensor （POFCOS） into arterial blood vessel,connect with photoelectric conversion measurement system to record the continuous dynamic rapid changes of arterial PO2(PaO2) in whole living animals. It should be the experimental evidence for the new theory of holistic integrative physiology and medicine(HIPM) forexplain the mechanism of respiratory control and regulation in whole circusof respiration-circulation-metabolism. Methods: ①Fabrication of ultrafast POFCOS, calibration and its measuring system: The distal part of 2 m optical fiber was heated and pulled until it became a tapered tip. After cleaning and drying, the tip of 1 mm tapered optical fiber was dip-coated into the luminophore doped polymer solution, then was slowly pumped out while solvent was quickly evaporated to form an oxygen sensing tip, which was dried at room temperature for 24 hours. ②Animal experiments: Under general anesthesia and intubation, goatwas mechanically ventilated with 40%~60% oxygen. We exposed both right and left carotid arteries and the left femoral artery by skin cutting, and inserted the POFCOS directly into the arteries via indwelling catheter. The end of POFCOS were connected to the personal computer through optical fiber, excitation and detection Y-type optical fiber coupler through photoelectric conversion, so as we can realize the continuous dynamic response of living goat carotid PaO2 under mechanical ventilation. We mainly analyzed the intra-breath wave-form alternate increase and decrease of PaO2 and their time delay between lung and carotid arteries.We completes breathing control whole loop to explain the mechanism of mutual breathing and the switching of inspiration and exhalation. Results: The POFCOS has a very fast T90 response time was set 100 ms for liquid. When the heart rate of 40%~60% oxygen mechanical ventilated living goat was ~110 bpm, the PaO2 of left and right carotid artery showed a same wave-sizeup and down following with the inspiration and expiration of ventilator, with a range of up to 15 mmHg. There weresignificant noises of PaO2 change recorded in the left femoral artery. The lung-carotid artery time delay is 1.5~1.7 s after inhalation and exhalation, PaO2 at both left and right carotid arteries starts toincrease and decrease. After two-three heartbeats after the start of lung ventilation, thealternate up-down wave-form information of the arterialized pulmonary vein blood after pulmonary capillaries waspumpedby left ventricle to the position of peripheral chemoreceptors,thus realizing the whole cycle of inhalation and exhalation. It alternately interrupted inhalation, i.e. switching inhalation to exhalation, and then interrupted exhalation,i.e. switching exhalation to inhalation. Conclusion: The ultra-fast reactive implantableoxygen sensor and its measuring system can measure the physiological waveform changes of PaO2 in living animals, which can provide experimental evidence for explaining the mechanism of switching of inspiration-expiration in HIPM.

[Effect of different work rate increasing rate on the overall function evaluation of cardiopulmonary exercise testing I-peak parameters and changes in respiratory exchange rate].

Objective: To observe the effect of healthy volunteers different work rate increasing rate cardiopulmonary exercise test (CPET) on the peak exercise core indicators and the changes of respiratory exchange rate (RER) during exercise, to explore the effect of different work rate increasing rate on CPET peak exercise related indicators. Methods: Twelve healthy volunteers were randomly assigned to a moderate (30 W/min), a relatively low (10 W/min) and relatively high (60 W/min) three different work rate increasing rate CPET on different working days in a week. The main peak exercise core indicators of CPET data: VO2, VCO2, work rate (WR), breathe frequency(Bf), tidal volume (VT), ventilation (VE), heart rate (HR), blood pressure (BP), Oxygen pulse(O2P), exercise time and RER for each period of CPET were analyzed using standard methods. The ANOVA test and paired two-two comparison was performed on the difference of each index in the three groups of different work rate increasing rate. Results: Compared with the moderate work rate group, the peak work rate of the lower and higher work rate groups were relatively lower and higher, respectively ((162.04±41.59) W/min vs (132.92±34.55) W/min vs (197.42±46.14) W/min, P<0.01); exercise time was significantly prolonged and shortened ((5.69 ± 1.33) min vs (13.49 ± 3.43) min vs (3.56 ± 0.76) min, P<0.01); peak RER (1.27 ± 0.07 vs 1.18 ± 0.06 vs 1.33 ± 0.08, P<0.01~P<0.05) and the recovery RER maximum (1.72±0.16 vs 1.61±0.11 vs 1.81±0.14, P<0.01~P<0.05) were significantly decreased and increased. Conclusion: Different work rate increasing rate of CPET significantly change the Peak Work Rate, exercise time, Peak RER, and maximum RER during recovery. The CPET operator should choose an individualized work rate increasing rate that is appropriate for the subject, and also does not use a fixed RER value as a basis for ensuring safety, the subject's extreme exercise, and early termination of exercise.

[Effect of different work rate increasing rate on the overall function evaluation of cardiopulmonary exercise testing II- sub-peak parameters].

Objective: To observe the effect of healthy volunteers different work rate increasing rate cardiopulmonary exercise testing (CPET) on the sub-peak parameters . Methods: Twelve healthy volunteers were randomly assigned to a moderate (30 W/min), a relatively low (10 W/min) and relatively high (60 W/min) three different work rate increasing rate CPET on different working days in a week. The core indicators related to CPET sub-peak exercise of 12 volunteers were compared according to standard Methods: anaerobic threshold (AT), oxygen uptake per unit power (ΔVO2/ΔWR), oxygen uptake eficiency plateau,（OUEP), the lowest average of 90 s of carbon dioxide ventilation equivalent (Lowest VE/ VCO2), the slope of carbon dioxide ventilation equivalent (VE/ VCO2 Slope) and intercept and anaerobic threshold oxygen uptake ventilation efficiency value (VO2/ VE@AT) and the anaerobic threshold carbon dioxide ventilation equivalent value (VE/ VCO2@AT). Paired t test was performed on the difference of each parameter in the three groups of different work rate increasing rate. Results: Compared with the relatively low and relatively high work rate increasing rate group, the moderate work rate increasing rate group uptake eficiency plateau, (42.22±4.76 vs 39.54±3.30 vs 39.29±4.29) and the lowest average of 90 s of carbon dioxide ventilation equivalent (24.13±2.88 vs 25.60±2.08 vs 26.06±3.05) was significantly better, and the difference was statistically significant (P<0.05); Compared with the moderate work rate increasing rate group, the oxygen uptake per unit work rate of the relatively low and relatively high work rate increasing rate group increased and decreased significantly ((8.45±0.66 vs 10.04±0.58 vs 7.16±0.60) ml/(min·kg)), difference of which was statistically significant (P<0.05); the anaerobic threshold did not change significantly ((0.87±0.19 vs 0.87±0.19 vs 0.89±0.19) L/min), the difference was not statistically significant (P>0.05). Conclusion: Relatively low and relatively high power increase rate can significantly change the CPET sub-peak sports related indicators such as the effectiveness of oxygen uptake ventilation, the effectiveness of carbon dioxide exhaust ventilation, and the oxygen uptake per unit work rate. Compared with the moderate work rate increasing rate CPET, the lower and higher work rate increasing rate significantly reduces the effectiveness of oxygen uptake ventilation and the effectiveness of carbon dioxide exhaust ventilation in healthy individuals. The standardized operation of CPET requires the selection of a work rate increasing rate suitable for the subject, so that the CPET sub-peak related indicators can best reflect the true functional state of the subject.

[Max test verify further clinical research for whether individualized symptom-limited cardiopulmonary exercise testing is the maximum extreme exercise].

Objective: To verify that the cardiopulmonary exercise testing (CPET) performed by clinical subjects is the maximum extreme exercise, we designed The Max test（Max）during clinical CPET. We used Max to verify the accuracy of the quantitative CPET evaluation result, and whether it is feasible and safe to use the specific value of a certain index as the standard for stopping CPET. Methods: Two hundred and sixteen cases from Fuwai Hospital were selected during June 2017 to January 2019,including 41 healthy person（control group） and 175with cardiovascular diseases（patient group）,The patients had a CPET peak RER ≤ 1.10, or the peak heart rate and peak blood pressure were basically non-responsive.The Max was first attempted in 60 subjects,and this study is further expanded . When the CPET ended, they had a 5-minute break, then the Max, during which, they cycled with a velocity of ≥ 60 r/min, at a constant intensity equivalent to to 130% of peak work,until exhausted.The difference and percentage difference between the peak heart rate and the peak oxygen uptake were calculated. ①If the percentage difference of heart rate and oxygen uptake are all less than -10%,then the Max is defined as failure,otherwise it is succesful. 2 If the percentage difference is between -10%~10%, then the Max is successful, which proved that the CPET is precise.③If the difference is ≥10%, the Max is successful, which proves that the CPET is non-extreme exercise. Results: Patient group's Peak VO2(L/min,ml/(min·kg)),anaerobic threshold (L/min,ml/(min·kg),%pred),Peak VO2/HR(ml/beat, % pred),Peak RER,Peak SBP,Peak WR,peak heart rate,OUEP （ratio,%pred） were lower than those of the control group(P<0.05)．The VE/ VCO2 Slope （ratio,%pred）and Lowest VE/ VCO2（ratio,%pred） were higher in the patient group than in the control group (P<0.05)．No adverse events occurred during the CPET and Max in all cases. Among the 216 cases,Max was successful in 198 cases(91.7%)．CPET was proved to be maximum extreme exercise for 182 cases,non-maximum extreme exercise for 16 cases,and failed in 18 cases(8.3%)．Conclusion: For CPET with a low peak RER and a maximum challenge,the Max can confirm the accuracy of the objective quantitative assessment of CPET. Max is safe and feasible,and that deserved further research and clinical application.

[Clinical study on the characteristics of exercise pathophysiological in patients with severe heart failure].

Objective: The cardiopulmonary function of patients with chronic heart failure (CHF) was severely limited, but the holistic integrative exercise pathophysiology is still unclear. Methods: After signed the consent form, Eighty three patients with severe CHF from October 2016 to October 2017 in Fuwai Hospital were performed Ramp incremental loading program CardioPulmonary Exercise Testing (CPET), and 12 normal subjects served as control. CPET were performed according to standard of Harbor-UCLA MC and the circulatory, respiratory and metabolic parameters during CPET were measured and analyzed. Results: Peak oxygen uptake (Peak VO2) in CHF (14.33±2.69) ml/(min·kg), (44.25±14.74)%pred was significantly lower than control ((29.42±5.46) ml/(min·kg), (83.88±6.28)%pred). Other core parameters of CPET such as anaerobic threshold (AT), peak oxygen pulse, oxygen uptake efficiency platform (OUEP), the lowest of carbon dioxide output ventilation ratio (Lowest VE/VCO2), and carbon dioxide output ventilation slope (VE/VCO2 Slope) in CHF were significantly different with the control group(P<0.01). The core parameters of lung function, such as forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, and carbon monoxide diffusion (DLCO) were significantly decreased (P<0.01). Systolic blood pressure during all stages of CPET in CHF was significantly lower than control group (P<0.05); Heart rate at AT, peak and recovery stages were significantly lower than control (P<0.01). Minute ventilation, tidal volume and respiratory frequency at rest, warm-up were significantly higher than control (P<0.05). Tidal volume at recovery was significantly higher than control (P<0.05). VO2 at AT, peak and recovery stages in CHF were significantly higher than control (P<0.01). Oxygen pulse at AT and peak were significantly higher than control (P<0.01). Pulse oxygen saturation during all stages of CPET in CHF were significantly lower than control (P<0.01). Conclusion: The decreased holistic functional capacity of cardiogenic CHF dominantly due to circulatory limitation, and secondly due to respiratory and metabolic limitation.

[The preliminary report of investigation: Using mask for cardiopulmonary exercise testing in Chinese children may result misinterpretation and misdiagnosis].

Objective: Observe the increased anatomical dead space of the mask, summarize the law of exercise induced oscillatory breathing (EIOB) in the results of CPET's new 9 figure, and analyze its incidence and age groups that are prone to oscillatory breathing. Methods: After signed the informed consent form by guardian, 501 children from pre-school to middle-school, aged 3~14 year, performed Harbor-UCLA standard protocol CPET with strict quality control in the CPET laboratory of Liaocheng Children's Hospital since 2014. CPET data was interpreted second by second from the breath by breath collection, averaged by 10s and then display by 9 plots. We analyzed the trends, pattern, incidence and age difference for EIOB and gas leakage. Results: The incidence of EIOB was the highest in the 3 to 6-year-old group, which was 42%. The 7 to 10-year-old group was 29.4% and the 11- to 14-year-old group was 29.9%. The three groups were tested by chi-square (x2=7.512), and the difference was statistically significant (P<0.05). 14 out of 508 children had air leakage during CPET, the incidence rate was 2.7%. Conclusion: The phenomenon of oscillatory breathing (OB) in children may be caused by the increased anatomical dead space of the mask, and it is not caused by disease. To improve the quality of CPET and to reduce clinical misdiagnosis, it is recommended to use a mouthpiece to decrease the dead space rather than the musk.