不同呼气末正压水平对呼吸窘迫综合征早产儿通气效率的影响

目的探讨不同呼气末正压（PEEP）水平对早产儿通气效率的影响。方法需机械通气肺透明膜病早产儿40例,随机分为低PEEP（0.49～0.59kPa）、高PEEP（0.59～0.78kPa）组进行机械通气,并予肺表面活性物质（PS）干预,上机稳定后15min,2、6、12、24h采集动脉血和血气分析,计算pa（O2）/FiO2比值、氧合指数和通气效率。结果低PEEP组pa（O2）/FiO2比值、氧合指数和通气效率均优于高PEEP组（Pa〈0.05）。结论呼吸窘迫综合征早产儿在接受PS后,低PEEP（0.49～0.59kPa）机械通气更为合适。     

呼气末正压对婴儿室间隔缺损术后心肺功能的影响

目的　 探讨婴儿先天性心脏病室间隔缺损 (窒缺 )修补术后机械通气时的最佳PEEP ,研究不同PEEP对其呼吸及心功能的影响。 方法 　选择体重小于 10kg ,术后畸形纠正满意者 ,共 15例。在PEEP 2、5、8、12cmH2 O时 ,分别测量呼吸系统顺应性(Cdyn)、气道阻力 (Raw)、生理死腔 (VD/TT)、动脉血氧分压 (PaO2 )、动脉血氧饱和度 (SaO2 )、氧合指数 (OI)、心率 (HR)、血压 (BP)、心输出量 (CO)、心排指数 (CI)、全身血管阻力 (SVR)、氧运输 (DO2 )。 结果　在PEEP 8cmH2 O时 ,Cdyn达高峰为 ( 5 16± 1 77)ml/cmH2 O(P <0 0 1) ,Raw和VD/VT 分别达最低值 ( 3 2 10± 17 2 3 )cmH2 O/ (L·s) (P <0 0 1)和 ( 0 5 5± 0 15 ) (P <0 0 1)。当PEEP从2cmH2 O渐增至 12cmH2 O时 ,HR、BP无显著性差异。CO和CI在 8cmH2 O时达高峰为 ( 2 2 9± 0 72 )L/min(P <0 0 1)和 ( 5 60±1 92 )L/ (min·m2 ) (P <0 0 1) ,SVR达最低值为 ( 881 6± 3 0 4 5 )Dyn .S/cm- 5(P <0 0 5 )。DO2 在 8cmH2 O时达高峰为 ( 997 5±3 44 6)ml/ (min·m2 ) (P <0 0 1)。 结论 　婴儿室缺术后 ,适当的PEEP可以改善呼吸功能和心血管功能 ,8cmH2 O是本组婴儿室缺术后的最佳PEEP ,可使DO2 达到最大化。     

呼气末正压对超声心输出量监测仪所测心指数的影响

目的评估不同水平呼气末正压（positive end expiratory pressure,PEEP）对机械通气患儿心指数的影响。研究肺复张对PEEP和心输出量之间关系的影响。     

不同呼气末正压对脓毒性休克合并急性呼吸窘迫综合征婴幼儿预后的影响

目的 评价不同呼气末正压(positive end-expiratory pressure,PEEP)对脓毒性休克合并急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)婴幼儿预后的影响.方法 将广西壮族自治区妇幼保健院PICU收治的60例脓毒性休克合并ARDS婴幼儿分为3组,每组20例,分别应用低、中、高三种水平PEEP(3、6、9 cmH2O,l cmH2O=0.098 kPa)进行呼吸机辅助通气,均采用压力控制机械通气模式,小潮气量(6 ～8 ml/kg)通气策略,同时根据美国危重病儿科高级生命支持协会2009年颁布的脓毒性休克指南指导液体复苏.监测3组患儿上机后6、24、48 h氧合指数(OI)、呼吸系统动态顺应性(Cdyn)、心脏指数(CI)的变化并统计每例患儿的液体入/出量,比较3组患儿机械通气时间、PICU住院时间及28 d病死率.结果 机械通气后6h开始,中、高PEEP组OI、Cdyn均明显好转,与低PEEP组比较差异均有统计学意义(P均＜0.01);中、低PEEP组CI明显高于高PEEP组,液体入量少于高PEEP组,差异均有统计学意义(P均＜0.01),3组液体出量比较差异无统计学意义(P＞0.05);中PEEP组呼吸机辅助通气时间[(5.40±0.61)d]、PICU住院时间[(7.00±0.61)d]均短于高、低PEEP两组[(6.23±0.90)d、(7.51±1.09)d;(8.23-±0.90)d、(9.14±1.21)d](P均＜0.01);3组患儿病死率比较差异无统计学意义(P＞0.05).结论 中PEEP能显著改善脓毒性休克合并ARDS患儿的肺功能,缩短机械通气时间,对血流动力学无严重不良影响.     

小潮气量加呼气末正压通气对腹腔镜下胆总管囊肿根治术患儿呼吸功能的影响

目的探讨小潮气量加呼气末正压机械通气对腹腔镜下胆总管囊肿根治术患儿呼吸功能的影响。方法选择45例择期全麻下腹腔镜胆总管囊肿根治术患儿,美国麻醉医师协会(ASA)分级Ⅰ~Ⅱ级,随机分为3组,气管插管后设定通气参数为VT 8 mL/kg,RR 22次/min,PEEP 0 cmH_2O,气腹后予不同通气方式:A组(n=15)潮气量(VT)设为6 mL/kg,呼吸频率(RR)24次/min,呼气末正压(PEEP)4 cmH_2O;B组(n=15)VT 10 mL/kg,RR 20次/min,PEEP 0 cmH_2O;C组(n=15)为对照组,通气方式不变。分别在气管插管后(T_0),气腹5 min(T_1),气腹30 min(T_2),气腹60 min(T_3),拔气管导管后20 min(T_4)监测血氧脉搏饱和度(SPO_2),呼气末CO_2分压(P盯CO_2),气道峰压(Ppeak),平均气道压(Pmean),平均动脉压(MAP)。于T_0、T_1、T_2、T_3、T_4五个时间点抽取动脉血进行血气分析,计算氧合指数(OI),肺泡动脉血氧分压差(A-aDO_2)。结果与T_0相比,三组患儿气腹后Ppeak,Pmean均升高,差异有统计学意义,B组尤为明显,气腹后P_(ET)CO_2均升高(P0.05),A、C组较B组更明显,各组气腹后A-aDO_2,较气腹前增高(P0.05),拔管后下降至与气腹前无异(P0.05),三组各时间点MAP组间比较差异无统计学意义(P0.05)。结论幼儿腹腔镜下胆总管囊肿根治术中采用小潮气量加呼气末正压通气,能降低气道压,改善动脉血气值,是安全可行的。     

非营养性吸吮对早产儿胃肠功能及体重增长的影响

目的 探讨早产儿早期非营养性吸吮(NNS)对其胃肠功能及体重增长的影响.方法 76例需经鼻胃管喂养的健康早产适于胎龄儿,出生体重＜2 500 g,胎龄＜35周,随机分为非营养性吸吮(NNS)组36例和对照组40例.NNS组在鼻胃管喂养前后吸空橡皮奶头5 min,每天7～8次,对照组单纯给予鼻胃管喂养(N-NNS),不足热量给予部分肠道外营养.观察体重、胃排空时间、肠道营养达418.4 kJ/(kg·d)时间,喂养耐受情况.结果 NNS组、对照组恢复出生体重时间分别为(8.6±3.9) d、(10.5±3.6) d,观察组明显缩短(P<0.05);NNS组胃半排空时间(58.3±22.9) min快于对照组(73.8±17.8) min,差异有统计学意义(P<0.05).NNS组热能达418.4 kJ/(kg·d)的时间(12.0±5.4) d较对照组(15.4±5.5) d明显缩短(P<0.05);胃残留发生率低于对照组,分别为16.7%、50.0%,差异有统计学意义(P<0.05).结论 NNS可促进胃排空,有利于早产儿生后胃肠功能发育,减少喂养不耐受的发生,促进体重增长.     

Nasopharyngeal oxygen therapy produces positive end-expiratory pressure in infants

The World Health Organisation recommends nasopharyngeal catheters as a safe and efficient method of oxygen administration in infants. However, little is known about the mechanisms of the improvement in oxygenation. The aim of the present study was to determine whether nasopharyngeal oxygen therapy produces positive end-expiratory pressure (PEEP). Nine spontaneously breathing infants (median age 13 months, range 10 days to 20 months) after heart surgery were investigated. All patients had normal pulmonary blood flow at the time of the study (Qp:Qs=1:1). Oxygen (oxygen fraction 1.0) was delivered by an 8 F catheter inserted into the nasopharynx (tip just visible below the soft palate). The pulmonary mechanics were analysed using a single compartment model of the respiratory system. Oesophageal pressure (Pes) at end-expiration, dynamic lung compliance (C(L)) and resistance (R(L)), minute ventilation, PaCO2 and PaO2 were measured at baseline without a nasopharyngeal catheter or oxygen, and at oxygen flows of 0.5 l/min, 1.0 l/min and 2.0 l/min. All the flows generated significant increases in PEEP. Mean difference in PEEP (SD, paired t-test versus baseline): 1.6 cm H2O (1.4, P=0.008) with 0.5 l/min of oxygen; 2.8 cm H2O (2.7, P=0.014) with 1.0 l/min of oxygen; and 4.0 cm H2O (2.9, P = 0.004) with 2.0 l/min of oxygen. There was a significant correlation between all the nasopharyngeal flows (in ml/kg per min) and the generated PEEP (P<0.001) and between the C(L) values and the generated PEEP (P < 0.05). There was no significant difference in PaCO2 and R(L). Minute ventilation was significantly less with nasopharyngeal oxygen than at baseline. As expected, PaO2 increased significantly with increasing oxygen flows. CONCLUSION: Administration of oxygen through an 8 F nasopharyngeal catheter at flow rates recommended by the World Health Organisation (0.5 l/min in newborns, 1.0 l/min in infants) produces moderate amounts of positive end-expiratory pressure. The levels achieved may contribute to an improvement in oxygenation by altering the visco-elastic properties of the lung.     

Optimal positive end-expiratory pressure therapy in infants and children with acute respiratory failure

Positive end-expiratory pressure (PEEP) has become a mainstay in the treatment of hypoxemic acute respiratory failure (ARF). Whereas PEEP improves arterial oxygen tension by decreasing intrapulmonary shunting, it may also impair cardiac output and hence decrease systemic oxygen transport. Inasmuch as optimizing oxygen transport is a goal of therapy in ARF, we sought to determine if the level of PEEP that results in maximal oxygen transport could be estimated from measurements of compliance of the respiratory system (Crs) or PaO2. We studied the effects of PEEP application on cardiorespiratory parameters in 15 children who required mechanical ventilation for ARF. Static Crs, PaO2, central venous and arterial blood pressures, indicator dilution cardiac index (CI), and oxygen transport were determined at 0, 3, 6, 9, 12, and 15 cm H2O PEEP. PaO2 increased significantly at PEEP levels greater than or equal to 9 cm H2O (p less than 0.001), while CI fell by 15% between 0 and 15 cm end-expiratory pressure (p less than 0.02). Crs and oxygen transport did not change significantly with increasing levels of PEEP. The level of PEEP resulting in maximal oxygen transport ranged from 0 to 15 cm H2O, and in all patients it corresponded to PEEP of best CI. At levels of PEEP above that associated with maximal oxygen transport, CI and oxygen transport fell significantly, while PaO2 continued to rise. No relationship between Crs and oxygen transport was observed. In our normovolemic patients with ARF, neither PaO2 nor Crs predicted PEEP of maximal oxygen transport.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term non-invasive positive airway pressure ventilation in infants

Aim: To evaluate the clinical application of long‐term non‐invasive ventilation (NIV) in infants with life‐threatening ventilatory failure with regard to: diagnosis, age at initiation, indication for and duration of treatment, clinical outcome and mortality and adverse effects. Patients and methods: The medical records of 18 infants treated in a home setting during a 7‐year period were reviewed. The criteria for ventilatory support were: (a) transcutaneous partial pressures of carbon dioxide (TcPCO₂) >6.5 kPa and oxygen (TcPO₂) < 8.5 kPa and (b) decreased cough ability and/or recurrent chest infections. Results: The median age at initiation was 4 months (range 1–12). NIV was initiated because of hypoventilation in 12 infants and because of reduced cough ability and/or recurrent infections in six infants. Tracheotomy was eventually needed in two infants. The median duration of treatment was 24 months (range 1–84). NIV produced significant improvements, with median TcPCO₂ falling from 9.9 to 6.1 kPa, and median TcPO₂ rising from 9.8 to 11.1 kPa. Conclusion: NIV can be successfully and safely used in infants with prolonged life‐threatening ventilatory failure, potentially avoiding intubation and tracheotomy.     

High positive end-expiratory pressure during high-frequency jet ventilation improves oxygenation and ventilation in preterm lambs

Increasing positive end-expiratory pressure (PEEP) is advocated to recruit alveoli during high-frequency jet ventilation (HFJV), but its effect on cardiopulmonary physiology and lung injury is poorly documented. We hypothesized that high PEEP would recruit alveoli and reduce lung injury but compromise pulmonary blood flow (PBF). Preterm lambs of anesthetized ewes were instrumented, intubated, and delivered by cesarean section after instillation of surfactant. HFJV was commenced with a PEEP of 5 cm H2O. Lambs were allocated randomly at delivery to remain on constant PEEP (PEEPconst, n = 6) or to recruitment via stepwise adjustments in PEEP (PEEPadj, n = 6) to 12 cm H2O then back to 8 cm H2O over the initial 60 min. PBF was measured continuously while ventilatory parameters and arterial blood gases were measured at intervals. At postmortem, in situ pressure-volume deflation curves were recorded, and bronchoalveolar lavage fluid and lung tissue were obtained to assess inflammation. PEEPadj lambs had lower pressure amplitude, fractional inspired oxygen concentration, oxygenation index, and PBF and more compliant lungs. Inflammatory markers were lower in the PEEPadj group. Adjusted PEEP during HFJV improves oxygenation and lung compliance and reduces ventilator requirements despite reducing pulmonary perfusion.     

早产儿呼吸窘迫综合征经鼻间歇正压通气治疗的Meta分析

Objective To agsess the efficacy of nasal intermittent positive pressure ventilation (NIPPV)in treatment of respiratory distress syndrome(RDS) in premature infants.Methods According to the requirements of Cochrane systematic review,a thorough literature search was performed among PubMed(1977-2008),Embase(1989-2008),OVID,Cochrane(2008),Chinese Digtal Hospital Library (www.chkd.cnki.net) and Chinese Biomedical Literature Disk Database(CBMdisc).Quality assessments of clinical trials were carried out Randomized controHed trials(RCTs)with NIPPV and RDS were enrolledand ReVnlan 4.2 software was used for meta-analysis.The trials were analyzed using relatire risk(RR) for dichotomous data,weighted mean difference(WMD) were used for continuous data,both kind of data were expressed by 95% confidence intervals(95%CI).For homogenous data(P≥0.10),fixed effects model was calculated,for heterogeneity data(P<0.10),random effects model was calculated.Results Five RCTs involving 284 premature infants diagnosed as respiratory distress syndrome(RDS) were included.Three studies comparing NIPPV with nasal continuous positive airway pressure(NCPAP) in the postextubation period,tHe extabation failure rate was 8.34%vs 40.79% in NIPPV group and NCPAP group,the NIPPV group had significantly lower extubation failure rates[RR 0.21(95%CI:0.10-0.45;P<0.001)].Two of the above.mentioned three studies analyzed bronchopulmonary dysplasia(BPD)rates,the incidence of BPD was 39.34%vs 54.39%in NIPPV group and NCPAP group,the NIPPV group had a trend towards lower BPD rates,but this did not reach statistical significance[RR 0.73(95%CI:0.49-1.07;P=0.11)].NIPPV was used as primary mode in two studies,one compared with conventional ventilation(CV),which detected that the NIPPV group had significantly lower BPD rates(10% vs.33.33%,P:0.04);the other compared with NCPAP,which also showed that NIPPV group had significantly lower BPD rates(2.33% vs.17.07%,P=0.03).Conclusion The primary mode NIPPV was found to be feasible as a method of ventilation in preterm infants with RDS,and Was associated with a decreased incidenee of BPD.In the postextubation period,NIPPV is more effective in preventing failure of extubation than NCPAP.     

早产儿呼吸窘迫综合征经鼻间歇正压通气治疗的Meta分析

Objective To agsess the efficacy of nasal intermittent positive pressure ventilation (NIPPV)in treatment of respiratory distress syndrome(RDS) in premature infants.Methods According to the requirements of Cochrane systematic review,a thorough literature search was performed among PubMed(1977-2008),Embase(1989-2008),OVID,Cochrane(2008),Chinese Digtal Hospital Library (www.chkd.cnki.net) and Chinese Biomedical Literature Disk Database(CBMdisc).Quality assessments of clinical trials were carried out Randomized controHed trials(RCTs)with NIPPV and RDS were enrolledand ReVnlan 4.2 software was used for meta-analysis.The trials were analyzed using relatire risk(RR) for dichotomous data,weighted mean difference(WMD) were used for continuous data,both kind of data were expressed by 95% confidence intervals(95%CI).For homogenous data(P≥0.10),fixed effects model was calculated,for heterogeneity data(P<0.10),random effects model was calculated.Results Five RCTs involving 284 premature infants diagnosed as respiratory distress syndrome(RDS) were included.Three studies comparing NIPPV with nasal continuous positive airway pressure(NCPAP) in the postextubation period,tHe extabation failure rate was 8.34%vs 40.79% in NIPPV group and NCPAP group,the NIPPV group had significantly lower extubation failure rates[RR 0.21(95%CI:0.10-0.45;P<0.001)].Two of the above.mentioned three studies analyzed bronchopulmonary dysplasia(BPD)rates,the incidence of BPD was 39.34%vs 54.39%in NIPPV group and NCPAP group,the NIPPV group had a trend towards lower BPD rates,but this did not reach statistical significance[RR 0.73(95%CI:0.49-1.07;P=0.11)].NIPPV was used as primary mode in two studies,one compared with conventional ventilation(CV),which detected that the NIPPV group had significantly lower BPD rates(10% vs.33.33%,P:0.04);the other compared with NCPAP,which also showed that NIPPV group had significantly lower BPD rates(2.33% vs.17.07%,P=0.03).Conclusion The primary mode NIPPV was found to be feasible as a method of ventilation in preterm infants with RDS,and Was associated with a decreased incidenee of BPD.In the postextubation period,NIPPV is more effective in preventing failure of extubation than NCPAP.