The Research Of Tidal Breathing Lung Function Acquired By Ultrasonic Flow Meter In Neonates

Objective: to discuss the application of ultrasonic flow technology in tidal breathing lung function of neonates. The tidal breathing lung functions and functional residual volumes of normal neonates were measured by ultrasonic flow meter, thus describing the characteristics of the tidal breathing lung functions and functional residual volumes of neonates with different weights and at different gestational ages, exploring the relationship between weight, gestational age, and tidal breathing lung function of neonates, and establishing normal values of tidal breathing lung functions and functional residual volumes of neonates with different weights.Methods:200cases were recruited from the neonates admitted into the neonatology department of Shenzhen Children’s Hospital between November2011and December2013. All recruited neonates were free from respiratory diseases and congenitalheart disease（CHD）, congenital diaphragmatic hernia（CDH）, neuromuscular disorders, deformities of the throat and chest wall and other diseases that may affect respiratory function. An ultrasonic flow meter was used to measure the tidal breathinglung functions and functional residual volumes of the recruited neonates. These cases were divided into Extremely Low Weight Group, Low Weight Group, Normal Weight Group and Large Weight Group based on the actual weights during the inspection. The features of TBFV loops of the neonates with different weights were analyzed, and the similarities and differences in tidal breathing lung function and functional residual volume among the neonates with different weights were identified. Similarly, the recruited neonates were divided into Small Premature Group, Late Premature Group, Full-term Group and Post-term Group based on gestational age. The similarities and differences in tidal breathing lung functions and functional residual volumes among the neonates at different ages were identified.97cases in Full-term Group were further divided into Normal Full-term Group and Small-for-gestational-age Group, and the differences in tidal breathing lung function and functional residual volume between the two groups were compared. The relations of weight and gestational age to tidal breathing lung function and functional residual volume of neonates were described respectively.Results: The results of the tidal breathing lung functions and functional residualvolumes of the neonates with different weights showed that RR of Extremely LowWeight Group and Low Weight Group were greater than Normal Weight Group andLarge Weight Group, and there was no significant statistical difference between Normal Weight Group and Large Weight Group. As to TV and FRC, Extremely LowWeight Group and Low Weight Group was lower than Normal Weight Group andLarge Weight Group[(12.98±1.96)ml、(13.92±1.46)ml/kg，(14.98±1.87)ml、(16.79±2.79)ml/kg，(20.37±2.48)ml、(18.04±1.96)ml/kg，(23.08±3.28)ml、(19.43±1.83)ml/kg](all P＜0.05). Tpef/Te, TEF75, TEF50and TEF25of the neonates in the four groupsincreased along with the weights[(26.91±2.65)%、(46.16±4.99)ml/s、(40.23±4.90)ml/s、(33.71±4.38)ml/s，(30.14±3.06)%、(48.89±5.12)ml/s、(44.97±4.82)ml/s、(37.36±4.73)ml/s，(33.51±2.65)%、(57.39±6.91)ml/s、(50.88±5.36)ml/s、(44.84±5.26)ml/s，(34.77±2.38)%、(59.26±4.16)ml/s、(52.90±4.24)ml/s、(46.01±4.80)ml/s](all P＜0.05). Therewere no significant statistical differences in TV/kg and MV of the neonates in thefour groups.The results of the tidal breathing lung functions and functional residual volumes of the neonates at different ages showed that RR of the four groups decreased asthe gestational age increased[(63.08±4.01)times/min，(58.44±4.66) times/min，(55.32±5.01) times/min，(51.42±3.24) times/min](P＜0.05). Tpef/Te and Vpef/Ve of SmallPremature Group and Late Premature Group were lower than those of Full-term Group and Post-term Group. There were no significant statistical differences betweenFull-term Group and Post-term Group[(26.87±2.49)%、(29.08±2.04)%，(30.74±2.96)%、(32.73±2.97)%，(32.01±2.35)%、(34.98±2.99)%，(33.87±2.18)%、(34.65±2.15)%]. The higher the gestational age was, TEF75, TEF50and TEF25were greater[(45.86±4. 07)ml/s、(39.97±5.32)ml/s、(33.31±5.28)ml/s，(48.93±3.92)ml/s、(45.07±4.32)ml/s、(37.96±4.66)ml/s，(55.99±6.33)ml/s、(51.08±5.13)ml/s、(44.64±5.91)ml/s，(59.76±4.11)ml/s、(53.01±4.44)ml/s、(46.21±4.09)ml/s]. There were significant statistical differences between Small Premature Group, Late Premature Group and Full-term Group (allP＜0.05), while there were no significant statistical differences between Full-termGroup and Post-term Group (P＞0.05).TV and FRC of Normal Full-term Group were higher than those of Small-for-gestational-age Group respectively[(19.27±2.25)ml、(17.59±1.62) ml/kg，(15.97±2.99)ml、(15.49±2.92) ml/kg]. The Tpef/Te, Vpef/Ve, TEF75, TEF50and TEF25of theNormal Full-term Group were higher than those of Small-for-gestational-age Group[(31.93±3.25)%、(34.56±2.76)%、(55.02±4.34)ml/s、(49.95±3.08)ml/s、(44.11±4.26)ml/s，(30.14±3.96)%、(32.41±3.87)%、(48.52±4.29)ml/s、(44.98±4.88)ml/s、(37.28±5.38)ml/s](all P＜0.05).The shape of TBFV loop indicted that the lower the neonate weight was, thesmaller the area within TBFV loop was, and the time expiratory phase curve ascending limb peak would occur earlier with a greater descending limb slope.95%CL of the tidal breathing lung functions and functional residual volumes ofneonates with different weights were shown as follows: Extremely Low Weight Group [TV(9.84-14.52)ml,Tpef/Te(24.13-27.98)%,TEF75(43.42-48.09)ml/s,TEF25(30.41-34.91)ml/s,FRC(12.47-14.85)ml/kg]；Low Weight Group [TV(14.09-16.31)ml,Tpef/Te(28.83-31.98)%,TEF75[(47.89-51.28)ml/s,TEF25(35.98-37.94)ml/s,FRC(14.93-17.46)ml/kg]；Normal Weight Group [TV(17.46-23.69)ml,Tpef/Te(32.12-35.69)%,TEF75(52.68-57.81)ml/s,TEF25(43.42-46.87)ml/s,FRC(17.86-19.13)ml/kg]；Large WeightGroup [TV(22.47-28.73)ml,Tpef/Te(33.08-36.07)%,TPEF75(52.17-62.16)ml/s,TPEF25(44.45-50.97)ml/s,FRC(19.04-20.36)ml/kg].Conclusions: The use of ultrasonic flow technology in measuring tidal breathinglung functions and functional residual volumes of neonates is highly sensitive and easy and simple to handle. It can get reliable data with high reproducibility and deserves to be widely used in newborn lung function tests. Tidal breathing lung function and functional residual volumes of neonate are closely related to its gestational age and weight during the test, and its relevance toweight is more evident than gestational age.The lower the weight and gestational age during the test are, the smaller the tidal volume and functional residual volume are, the greater the RR is, the lower theexpiratory flow rate is and the airway resistance is higher.A preliminary summary is made to put forward the reference range of tidal volume and functional residual volume of neonates with different weights, thus providing evidences for breathing machine parameter setting of neonate aid, respiratory system development evaluation, and disease diagnosis and treatment.