氧疗的方式及升级的时机

低氧血症是多种危重症的常见表现之一, 氧疗是改善低氧血症最有效的治疗, 若选择不合适的氧疗方式或延误升级氧疗的时机, 可能造成细胞及组织持续缺氧、功能障碍甚至器官衰竭。当氧疗开始后, 需要严密观察患者临床症状、体征、指脉氧饱和度、血气分析等多种指标, 并充分利用近年来新兴的呼吸速率氧合指数、改良呼吸速率氧合指数、VOX指数、列线图模型及在线计算器等多种工具综合评定患者氧合动态变化, 及时调整氧疗方式及参数, 以改善患者预后。     

呼吸指数及氧合指数动态监测在新生儿呼吸窘迫综合征中的应用

目的 探讨呼吸指数(RI)及氧合指数(OI)动态监测在新生儿呼吸窘迫综合征(NRDs)机械通气治疗中的价值.方法 先取2006年12月-2007年11月在成都市妇幼保健院NICU治疗的24例未使用肺泡表面活性物质治疗的NRDS患儿,采用同步间歇指令通气模式,根据其预后分为存活组(16例)和死亡组(8例),比较二组患儿在机械通气过程中RI,OI,肺泡-动脉血氧分压差[p(A-a)(O2)]和pa(O2)的变化,动态观察二组患儿PI、P(A-a)(O2、OI值的变化,并进行比较.结果 在机械通气后2 h,存活组和死亡组患儿RI、OI、p(A-a)(O2)分别进行比较,差异均有显著性(t=2.47,2.62,3.01 P.<0.05).在机械通气过程中,存活组患儿RI、P(A-a)(O2)和OI随通气时间进展而逐渐降低,不同时间点RI、P(A-a)(O2)及OI值比较,差异均有显著性意义(F=93.68,373.56.41.35(0.05).RI与P(A-a)(O2)值,RI与OI值均呈正相关(r=0.766,0.773 Pa<0.os).结论 RI、OI可作为NRDS患儿病情严重程度和疗效判断的指标之一.     

呼吸指数及氧合指数的监测在儿童急性呼吸窘迫综合征中的应用

目的通过监测呼吸指数(RI)及氧合指数(OI)在儿童急性呼吸窘迫综合征(ARDS)中的变化,探讨RI及OI在ARDS的诊断及治疗中的价值。方法将2002年1月~2004年12月在上海儿童医学中心PICU治疗的12例ARDS患儿(实验组),与同期住院治疗的20例肺炎合并急性呼吸衰竭的患儿(对照组)进行回顾性研究,监测两组患儿在机械通气早期(上机2 h内)、中期(上机48~72 h间)以及撤机前(撤机前2 h到撤机前0.5 h)的RI、OI、肺泡-动脉血氧分压差[P(A-a)O2]、血氧饱和度(SaO2)、动脉血氧分压(PaO2)的变化。结果两组患儿在机械通气早期及中期RI、OI、P(A-a)O2比较有显著性差异(P<0.01),而SaO2、PaO2比较差异无显著性(P>0.05);在撤机前两组患儿各项指标比较均无差异(P>0.05)。结论RI、OI可作为ARDS早期诊断、疗效观察及指导撤机的指标。     

空气氧气混合器头罩氧疗的临床研究

目的 探讨空气氧气混合器(空氧混合器)头罩氧疗的疗效及安全性.方法 将62例低氧血症的新生儿分为研究组32例和对照组30例,分别应用空氧混合器头罩和单纯头罩进行氧疗,其间监测吸入氧浓度、血气、经皮血氧饱和度,观察其疗效和安全性.结果 两组纠正低氧血症的有效率分别为87.5%、83.3%,差异无显著性(P＞0.05).为维持经皮血氧饱和度85%～95%,研究组所用氧流量和吸人氧浓度分别为(1.5 4±0.5)L/min、(35 ±5)%,明显低于对照组(6.5±1.5)L/min、(65 ±15)%,差异有显著性(P＜0.01,P＜0.05).对照组20%的病例发生CO2潴留,而研究组无一例发生.结论 空氧混合器头罩氧疗效果好,不良反应小,适合新生儿临床应用.     

采用不同给氧方式的临床疗效观察

氧疗在新生儿抢救中是最常见的方法之一。氧疗的效果不仅与绘氧浓度有关，与给氧方式也有着密切的关系。为了了解在不同给氧方式下患儿的疗效，作了以下观察。一般资料一、对象选择患各种疾病并有不同程度的缺氧，在本院新生儿科诊治的患儿17例。其中吸入性肺炎14例，湿肺2例，红细胞增多症1例，其中3例为人工呼吸机应用撤离后的患儿。出生体重2699±837克（1748～3460克）；股龄37±2．3周（34～40周）；男女之比为11：6。测是日龄4．7±3．5（1～12）天。二、测定方法同一患儿先后在氧疗前，不同氧流量情况下及面罩，头罩（大、小规格各一…     

高浓度氧对早产鼠肺一氧化氮合酶基因表达的影响

目的　探讨高浓度氧 (简称高氧 )对早产鼠肺一氧化氮合酶 (NOS)分布及基因表达的影响。方法　将 2 1d孕早产鼠随机分为高氧暴露组 (简称高氧组 )和空气对照组 (对照组 ) ,分别置于常压高氧仓中 (氧体积分数 >0 95 )和正常空气中暴露 7d ,采用逆转录 聚合酶链反应 (RT PCR)、免疫蛋白分析和免疫组织化学染色观察NOS分布及基因表达。此外对肺组织干 /湿重比值 ,支气管肺泡灌洗液 (BALF)成份和肺病理组织变化也进行了对比分析。结果　高氧组与对照组比较 ,早产鼠肺组织有明显水肿、出血和炎症 ;高氧组支气管肺泡灌洗液中蛋白含量 (中位数为 1 4 9g/L)、细胞数 (中位数为 139 70× 10 7/L)和肺组织干 /湿重比值 (5 5 7± 0 2 9)较对照组 (分别为 :0 32g/L、16 30× 10 7/L、5 2 9± 0 2 5 )均明显增加 (t=2 8、2 1、2 2 9,P均 <0 0 5 ) ;高氧组肺组织内皮细胞型一氧化氮合酶 (eNOS)mRNA、eNOS和诱导型一氧化氮合酶 (iNOS)蛋白表达 (分别为 :1 0 2± 0 0 6、8 77± 0 75、4 6 1± 0 6 5 )较对照组 (分别为 :0 70± 0 12、4 5 2± 1 0 2、3 2 4± 0 5 5 )明显增加 (t =6 36、8 14、3 2 1,P <0 0 1、P <0 0 1、P <0 0 5 )。iNOSmRNA也显示有增加的趋势 ,但差异无统计学意义 ,同时免疫组织化     

新生儿脑氧合及脑功能监测的意义

围生期新生儿易发生各种类型的缺氧，导致脑损伤，严重者遗留神经系统后遗症。早期客观评价新生儿脑氧合、血流动力学、脑反应的改变，及时发现并治疗脑组织缺氧，已成为临床迫切需要解决的问题。近红外光谱技术（Near Infrared Spectroscopy，NIRS）可直接反映组织中氧与血红蛋白的氧合与解离情况，表明组织中的血氧合状态，是脑组织氧合、血流及灌注客观评价的手段，     

氧疗

氧疗是指利用高于大气浓度的氧进行治疗的一种方法,一般用于缺氧患儿的治疗和危重症病例的抢救.机体内氧的摄取与氧利用处于一种动态平衡,氧过多或过少均对机体不利.因此氧疗也具有正反两方面作用:缺氧患儿可通过氧疗纠正机体缺氧以及因缺氧而引起的病理生理变化.     

碳氧血红蛋白测定对新生儿黄疸诊断的价值

目的：探讨碳氧血红蛋白测定在新生儿黄疸诊断中的临床价值。方法：189例新生儿黄疸患儿(新生儿溶血病75例,感染52例,颅内出血32例,晚发母乳黄疸30例)及142例对照组患儿同步测定动脉化毛细血管血碳氧血红蛋白(COHb)和血清总胆红素(STB);溶血组予大剂量静脉免疫球蛋白治疗后测定COHb及STB,应用SAS6.12统计软件进行处理。结果：溶血组COHb及STB分别为(3.64±0.83)%,330.84±77.15μmol/L,显著高于对照组的(2.38±0.35)%和130.18±32.86μmol/L(P<0.01);颅内出血组COHb及STB分别为(2.48±0.53)%,184.15±29.35μmol/L,高于对照组的(2.24±0.32)%及112.11±17.45μmol/L(P<0.05);感染及母乳黄疸组STB分别为286.71±45.66μmol/L,299.15±44.14μmol/L,显著高于对照组146.23±31.26μmol/L及57.33±7.83μmol/L(P<0.01),而COHb为(2.36±0.50)%及(1.84±0.49)%与对照组(2.20±0.39)%及(1.67±0.43)%比较,差异无显著性(P>0.05)。溶血性高间胆组STB低于非溶血性高间胆组(P<0.01),而COHb显著高于后者(P<0.01)。溶血组大剂量静脉免疫球蛋白治疗前后COHb分别为(3.64±0.83)%及(2.68±0.51)%,STB分别为330.84±77.15μmol/L及230.18±42.96μmol/L,治疗前后比较差异有显著性(P<0.01)。结论：COHb测定可作为胆红素产量的指标,有助于新生儿黄疸病因诊断及指导治疗。     

Clinical utility of augmentation index as a new parameter of peripheral circulation in human fetuses

Background

Augmentation index (AI) is calculated from the central arterial pressure or pulse waveform and known as a parameter to evaluate arterial vascular function in adults. Patients with deterioration of peripheral circulation will demonstrate increased AI values as well as those with cardiovascular risks. It is because increased AI is caused by the early timing of the reflection wave from the periphery. On the other hand, in fetuses, although arterial pressure waveforms are not available, pulse waveforms of fetal descending aorta are recordable by using an echo-tracking system. Therefore in this study we aimed to evaluate the utility of fetal AI calculated from aortic pulse waveforms for detecting the altered peripheral circulation in human fetuses.

Study design

Fetal AI was calculated from pulse waveforms in the descending aorta using an echo-tracking system. In a cross-sectional study of 105 normal fetuses, the reference range was constructed using linear regression analysis. Retrospectively, 36 growth-restricted fetuses were divided into 2 subgroups, normal (n = 21) and increased AIx (n = 15), based on the 90th percentile value of normal fetuses. Clinical parameters were compared using Fisher's exact test or Mann–Whitney U test.

Results

Fetal AI decreased linearly with advancing gestational age (r² = 0.820). The incidences of umbilical artery absent/reversed end-diastolic flow, brain-sparing effect, and oligohydramnios were significantly higher in the increased AI group than the normal AI group.

Conclusion

Fetal AI has a possibility to detect deteriorated peripheral circulation in the fetal body as well as fetoplacental circulation.     

加温湿化高流量经鼻导管氧疗的作用机制及在儿科的应用

加温湿化高流量经鼻导管氧疗(heated humidified high flow nasal cannula oxygen therapy,HFNC)具有改善呼吸做功,产生呼吸末正压效应,操作简单,患者耐受性优良,安全性高的特点.目前已经广泛用于新生儿相关的呼吸支持治疗,但缺乏在婴幼儿和儿童的广泛使用和研究.从HFNC作用机制及儿科生理学角度看,适合用于婴儿病毒性毛细支气管炎、儿童肺炎、哮喘、急性呼吸窘迫综合征以及拔管后呼吸支持治疗.HFNC应该成为儿科首选的常规氧疗模式.     

Oxygen in the neonatal period: Oxidative stress,oxygen load and epigenetic changes

Preterm infants frequently require positive pressure ventilation and oxygen supplementation in the first minutes after birth. It has been shown that the amount of oxygen provided during stabilization, the oxygen load, if excessive may cause hyperoxia, and oxidative damage to DNA. Epidemiologic studies have associated supplementation with pure oxygen in the first minutes after birth with childhood cancer. Recent studies have shown that the amount of oxygen supplemented to preterm infants after birth modifies the epigenome. Of note, the degree of DNA hyper-or hypomethylation correlates with the oxygen load provided upon stabilization. If these epigenetic modifications would persist, oxygen supplied in the first minutes after birth could have long term consequences. Further studies with a robust power calculation and long-term follow up are needed to bear out the long-term consequences of oxygen supplementation during postnatal stabilization of preterm infants.     

The value of oxygen index and base excess in predicting the outcome of neonatal acute respiratory distress syndrome

ObjectiveThis study aimed to identify the predictors and threshold of failure in neonatal acute respiratory distress syndrome.MethodsNewborns with severe acute respiratory distress syndrome aged 0–28 days and gestational age ≥36 weeks were included in the study if their cases were managed with non-extra corporal membrane oxygenation treatments. Patients were divided into two groups according to whether they died before discharge. Predictors of non-extra corporal membrane oxygenation treatment failure were sought, and the threshold of predictors was calculated.ResultsA total of 103 patients were included in the study. A total of 77 (74.8%) survived hospitalization and were discharged, whereas 26 (25.2%) died. Receiver operating characteristic analysis of oxygen index, pH, base excess, and combinations of these indicators demonstrated the advantage of the combination of oxygen index and base excess over the others variables regarding their predictive ability. The area under the curve for the combination of oxygen index and base excess was 0.865. When the cut-off values of oxygen index and base excess were 30.0 and ?7.4, respectively, the sensitivity and specificity for predicting death were 77.0% and 84.0%, respectively. The model with base excess added a net reclassification improvement of 0.090 to the model without base excess.ConclusionThe combination of oxygen index and base excess can be used as a predictor of outcomes in neonates receiving non-extra corporal membrane oxygenation treatment for acute respiratory distress syndrome. In neonates with acute respiratory distress syndrome, if oxygen index >30 and base excess <?7.4, non-extra corporal membrane oxygenation therapy is likely to lead to death.     

Home oxygen therapy after hospital discharge

Home oxygen therapy is increasingly prescribed for various conditions in the neonatal period, particularly for infants with bronchopulmonary dysplasia. Due to limited evidence on indication, minimal target oxygen saturation, monitoring, application and discontinuation of home oxygen therapy clinical practice varies widely throughout the world. International guidelines provide recommendations mostly on the basis of nonsystematic clinical observations. Most relevant points for the clinical management of home oxygen therapy include a minimal target oxygen saturation of equal to or greater than 93%, the provision of a home monitoring of oxygen saturation ideally with a memory function, and the conduct of continuous overnight oximetry or polysomnography during weaning from supplemental oxygen. This review summarizes relevant literature as well as existing guidelines and recommendations on home oxygen therapy to aid clinicians in the management of these patients and identifies areas for future research.     

Home oxygen therapy in infants with bronchopulmonary dysplasia: a prospective study

We followed the clinical course of 21 infants with bronchopulmonary dysplasia enrolled in a prospective home O₂ therapy programme during a 4-year-period. Mean gestational age was 28.5 weeks (range, 25–36 weeks) and mean birth weight 1093 g (range 630–2750 g). Infants were regularly monitored to maintain pulse oximeter O₂ saturation over 94%–95%. The source of O₂ was liquid oxygen and was delivered by nasal cannula. During the follow up oxygenation was assessed by SatO₂ measurement, cardiac function by Doppler echocardiography and respiratory function by the occlusion technique. All patients had an ophthalmological follow up. The mean age of the infants at discharge was 3.7 months (range 1.7–8.6) and mean weight 2830 g (range 2150–3780 g). At discharge 8 infants had right ventricular hypertrophy (RVH) and four of them had pulmonary hypertension. Mean duration of home O₂ therapy was 97 days (range 15–320 days) and the mean age of discontinuation of O₂ was 6.9 months (range 3–14.7 months). The cardiological follow up was benign: the ECG signs of RVH disappeared by 12 months of age in six out of eight infants and the right ventricular pulmonary pressure, as measured by the Doppler method, normalised in the four patients in whom it was detected. No relationship was found between respiratory mechanics and the duration of O₂ therapy. Weight gain was poor with mean growth at the 3rd percentile for females and just below the 3rd percentile for males. Twelve of the 21 infants required 25 rehospitalizations. No one presented deterioration of retinopathy of prematurity that was present in 16 infants at discharge; at 12 months retinopathy was resolved in 14 infants. A total of 2025 hospital days were saved, representing a significant financial saving. Conclusion Home O₂ therapy permits the safe early discharge of O₂-dependent BPD infants and it reduces significantly the length of time spent in hospital which represents a considerable financial saving. Received: 17 December 1996 and in revised from: 15 April 1997 / Accepted: 29 April 1997