两种气体持续气道正压在单肺通气中对肺内分流与氧合的影响

目的观察氧气与空气在不同持续气道正压(CPAP)水平下对单肺通气氧合与肺内分流的影响.方法随机将14例单肺通气下行开胸手术的病人平均分成组Ⅰ(氧气组)和组Ⅱ(空气组),常规诱导、插入双腔支气管导管后行单肺通气20min后,组Ⅰ利用氧气向无通气侧肺给予5 cmH2O的CPAP,15 min后再给予10 cmH2O的CPAP;而组Ⅱ利用空气向无通气侧肺给予5 cmH2O的CPAP,15 min后再给予10 cmH2O的CPAP.分别记录单肺通气前、单肺通气20min、5 cmH2O的CPAP15 min、10 cmH2O的CPAP15min、术毕恢复双肺通气15min所测得的动脉血pH、PaO2和PaCO2等数据,并计算Qs/Qt值.结果组Ⅰ:5 cmH2O CPAP 15 min比单肺通气20min:PaO2显著增高(P＜0.05)、Qs/Qt显著降低(P＜0.05).10 cmH2O CPAP 15 min比单肺通气20min:PaO2显著增高(P＜0.05)、Qs/Qt显著降低(P＜0.05).10 cmH2O CPAP 15 min比5 cmH2O CPAP 15 min:PaO2显著增高(P＜0.05)、Qs/Qt显著降低(P＜0.05).组Ⅱ:5 cmH2O CPAP 15 min比单肺通气20min:PaO2、Qs/Qt无显著差异(P＞0.05).10 cmH2O CPAP 15 min比单肺通气20min:PaO2显著降低(P＜0.05),Qs/Qt显著增加(P＜0.05).结论氧气提供CPAP可有效改善单肺通气造成的低氧状况,10 cmH2O CPAP比5 cmH2O CPAP对改善Qs/Qt、提高PaO2更有效.用空气提供CPAP不能使单肺通气产生的低氧状况得到改善.     

早期持续气道正压通气对小儿重症肺炎并发呼吸衰竭血气指标及预后的影响

目的探讨早期持续气道正压通气(CPAP)对小儿重症肺炎并发呼吸衰竭血气指标及预后的影响。方法选取本院接收诊治的68例重症肺炎并发呼吸衰竭患儿为研究对象,按照随机单双数法将所有患儿分为对照组和研究组,各34例。对照组患儿予以鼻导管吸氧等常规治疗,研究组患儿予以早期CPAP治疗。治疗1 d后,对比2组患儿治疗前后血氧饱和度(SaO_2)、动脉血氧分压[p(O_2)]、动脉血二氧化碳分压[p(CO_2)]及氢离子浓度指数(p H值)等指标,并分析2组患儿预后情况。结果治疗后,2组患儿SaO_2、p(O_2)、p H值水平均显著升高,p(CO_2)水平显著降低;研究组患儿SaO_2、p(O_2)、pH值水平均显著高于对照组,p(CO_2)水平显著低于对照组(P 0. 05)。2组患儿并发症发生率相比,差异无统计学意义(P 0. 05);研究组患儿死亡率为2. 94%,低于对照组的20. 59%,差异有统计学意义(P 0. 05)。结论早期CPAP治疗重症肺炎并发呼吸衰竭患儿的效果显著,能够促进患儿血气指标的改善,同时能够有效减少其并发症及病死情况的发生,且能够促进患儿预后恢复。     

开胸手术单肺通气期间非通气侧肺实施持续气道正压对肺内分流和氧合的影响

目的 观察单肺通气期闻非通气侧肺实施持续气道正压（CPAP）对肺内分流和氧合的影响。 方法 40例择期开胸单肺通气行肺叶切除患者,随机分对照组（A组）和CPAP组（B组）,每组20例。单肺通气时A组病人非通气侧支气管导管与大气相通,B组病人非通气侧肺给予5cmH2O的CPAP处理。分别于单肺通气前,单肺通气30min,单肺通气结束,恢复双肺通气30min抽动脉血测血气分析,根据公式计算肺内分流率。 结果 A组病人在单肺通气30min及单肺通气结束时PaO2明显降低,而与单肺通气前比较Qs／Qt则明显增高（P〈0.05）。B组病人PaO2及Qs／Qt虽有改变但各时点之间比较差异无显著性（P〉0．05）。单肺通气30min及单肺通气结束时,PaO2B组较A组高,而Qs／Qt低于A组（P〈0．05）。 结论 单肺通气期间非通气侧肺实施5cmH2O CPAP可明显提高氧分压,减少肺内分流。     

老年患者施行不同通气模式对单肺通气氧合及气道压力的影响

目的观察老年患者胸科手术时单肺通气期间不同通气模式对患者气道压力和氧合的影响。方法需行单肺通气麻醉的老年手术病人120例,其中男性80例,女性40例,年龄60岁以上。将120名患者分为例组,施行全麻诱导双腔插管后行双肺通气,进胸后分别再进行不同通气模式的单肺通气,单肺通气开始后,其中容量控制通气模式(VCV)组(Ⅰ组)VT=10 ml/kg,f=10;压力控制通气模式(PCV)(Ⅱ组)压力设定为达10 ml/kg潮气量的压力值,f=10;VCV组(Ⅲ组)VT=7 ml/kg,f=14;PCV组(Ⅳ组)压力设定为达7 ml/kg潮气量的压力值,f=14;VCV+选择性通气肺呼气末正压组(PEEP)(Ⅴ组)VT=7 ml/kg,f=14,PEEP=5 cm H2O;PCV+PEEP组(Ⅵ组)压力设定为达7 ml/kg潮气量的压力值,f=14,PEEP=5 cm H2O。定时记录数据。结果单肺通气30 min后、单肺通气60 min后,Ⅲ组和Ⅳ组相比氧合具有显著统计学差异(P<0.05),Ⅲ组和Ⅴ组相比氧合具有显著统计学差异(P<0.05),Ⅳ组和Ⅵ组相比氧合具有显著统计学差异(P<0.05)。结论为了改善单肺通气时出现的低氧血症和确保患者在手术中的安全,需要合理选择通气模式,达到提高单肺通气效果的目的,使单肺通气技术得到广泛的推广。     

新生儿肺透明膜病持续气道正压给氧的护理

新生儿肺透明膜病 (ＨＭＤ)是新生儿呼吸衰竭最常见的病因之一 ,主要见于未成熟儿 ,发病率与胎龄成反比 ,发生时或出生后不久即有呼吸窘迫表现 ,2 4～ 4 8ｈ达高峰 ,72ｈ后症状缓解 ,自然进程 3～ 5天 ,由于肺发育不成熟 ,其产生或释放表面活性物质不足 ,引起广泛的肺泡萎陷和顺应性降低。ＣＰＡＰ(持续气道正压给氧 ) ,对有自主呼吸的ＨＭＤ婴儿提供持续的气道扩张压 ,使萎陷的肺泡重新张开 ,并在呼气末保持正压 ,增加功能残气量 ,增加肺泡的气体交换面积 ,减少肺内分流 ,改善氧合。ＨＭＤ治疗的最重要的目的是保证机体足够的氧合 ,以维持…     

鼻塞持续气道正压通气治疗早产儿的护理

总结97例早产儿经鼻塞持续气道正压通气治疗的护理措施,重点是加强病情观察,监测生命体征和CPAP的运转情况,预防并发症和继发感染,加强呼吸道的管理和撤机管理等.     

鼻塞持续气道正压通气治疗早产儿的护理

总结97例早产儿经鼻塞持续气道正压通气治疗的护理措施，重点是加强病情观察，监测生命体征和CPAP的运转情况，预防并发症和继发感染，加强呼吸道的管理和撤机管理等。     

经鼻持续气道正压通气联合肺表面活性物质治疗早产儿肺透明膜病的疗效

目的探讨经鼻持续气道正压通气（continuous positive airway pressure,CPAP）联合肺表面活性物质（PS）治疗早产儿肺透明膜病的临床疗效。方法对30例肺透明膜病患儿均常规保暖及监护、气道管理（简易开放式面罩吸氧）。采用呼吸机经鼻CPAP治疗,治疗时间为患儿生后15 min～2 h。初调参数：氧浓度（FiO2）40%～50%,呼气末正压（PEEP）0.29～0.78 kPa。采用PS治疗。首剂治疗时间为患儿生后15 min～2 h,100 mg.kg-1.次-1气管插管下气管内滴入;4～6 h后依据病情考虑重复应用。连用72 h。结果 30例患儿治疗后0.5～72 h pH、PaO2、PaCO2、FiO2、PEEP值及PaO2/FiO2比值与治疗前比较差异均有统计学意义（P〈0.05或P〈0.01）。治疗24 h后胸部X线片分期中Ⅰ期有5例胸部X线片正常,1例加重;Ⅱ期有2例转为Ⅰ期,7例无变化;2例转为Ⅲ期;Ⅲ期3例减轻。治疗72 h后胸部X线片转正常25例,肺炎5例。治愈28例（93.3%）,放弃治疗1例（3.3%）,胸部X线片分期中Ⅲ期并肺炎上呼吸机1例（3.3%）。结论采用经鼻CPAP联合PS治疗早产儿肺透明膜病能取得满意的效果,是肺透明膜病较理想的治疗方法。     

气道压力释放通气和持续气道正压开放肺的比较

目的探讨气道压力释放通气（APRV）与持续气道正压（CPAP）通气两种通气模式实施肺复张策略治疗急性呼吸窘迫综合征（ARDS）对血流动力学、肺力学和氧代谢指标的影响。方法选择ARDS行机械通气及脉搏轮廓法持续血流动力学监测的患者15例，随机实施APRV模式肺复张或CPAP模式肺复张，每隔4h复张1次。其中APRV组设定高水平压力（Phigh）为35cm H2O（1cm H2O=0．098kPa），低水平压力（Plow）为压力-容积（P—V）曲线的下拐点（LIP）；CPAP组设定CPAP为35cm H2O；两组持续时间均为40s。记录复张前后的肺力学、氧代谢指标以及复张时的血流动力学变化。结果在APRV模式下行肺复张时心脏指数（CI）轻度下降，且持续时间较短。两种复张模式均可使肺顺应性等力学参数及氧合明显改善，以APRV模式尤为明显。结论采用APRV模式进行ARDS肺复张治疗可避免镇静剂的使用，对血流动力学干扰较小，对肺力学及氧合的改善优于CPAP模式。     

胸腔镜手术单肺通气期间非通气侧肺不同处理方法对动脉血氧合肺内分流的影响

目的观察胸腔镜手术单肺通气期间非通气侧肺不同处理方法对动脉血氧合肺内分流的影响。方法将30例择期行胸腔镜手术的病人按单肺通气期间非通气侧肺不同处理方法分为三组:A组将非通气侧肺的支气管导管旷置于大气中,使肺自行萎陷;B组将非通气侧肺的支气管导管内置入一通过湿化装置与氧流量表相连的细导管,氧流量为1 L/min;C组将非通气侧肺的支气管导管出口处接上一负压吸引管,调节适宜压力使肺完全萎陷。在单肺通气前、通气后30和60 min分别采动脉血作血气分析并计算QS/Qt值。结果PaO2在OLV 60 min时A组下降明显,B和C组与A组相比差异有显著性(P<0.05);QS/Qt在OLV 30 min时B和C组与A组相比差异有显著性(P <0.05), OLV 60 min时B和C组与A组相比差异有极显著性(P<0.01),B组与C组间在OLV 30和60 min PaO2,QS/Qt差异均无显著性(P >0.05)。结论B组与C组的非通气侧肺处理方法都能降低肺内分流,提高动脉血氧合,但C组的方法更方便胸腔镜手术中的操作。     

Noninvasive positive pressure ventilation in infants with upper airway obstruction: comparison of continuous and bilevel positive pressure

Objective This study evaluated the efficacy of noninvasive continuous positive pressure (CPAP) ventilation in infants with severe upper airway obstruction and compared CPAP to bilevel positive airway pressure (BIPAP) ventilation.Design and setting Prospective, randomized, controlled study in the pulmonary pediatric department of a university hospital.Patients Ten infants (median age 9.5 months, range 3—18) with laryngomalacia (n=5), tracheomalacia (n=3), tracheal hypoplasia (n=1), and Pierre Robin syndrome (n=1)Interventions Breathing pattern and respiratory effort were measured by esophageal and transdiaphragmatic pressure monitoring during spontaneous breathing, with or without CPAP and BIPAP ventilation.Measurements and results Median respiratory rate decreased from 45 breaths/min (range 24–84) during spontaneous breathing to 29 (range 18–60) during CPAP ventilation. All indices of respiratory effort decreased significantly during CPAP ventilation compared to unassisted spontaneous breathing (median, range): esophageal pressure swing from 28 to 10 cmH₂O (13–76 to 7–28), esophageal pressure time product from 695 to 143 cmH₂O/s per minute (264–1417 to 98–469), diaphragmatic pressure time product from 845 to 195 cmH₂O/s per minute (264–1417 to 159–1183) During BIPAP ventilation a similar decrease in respiratory effort was observed but with patient-ventilator asynchrony in all patients.Conclusions This short-term study shows that noninvasive CPAP and BIPAP ventilation are associated with a significant and comparable decrease in respiratory effort in infants with upper airway obstruction. However, BIPAP ventilation was associated with patient-ventilator asynchrony.     

A comparative study of the cardiorespiratory effects of continuous positive airway pressure breathing and continuous positive pressure ventilation in acute respiratory failure

Positive end expiratory pressure (PEEP) produces cardiopulmonary effects whether administered by controlled positive pressure ventilation (CPPV) or continuous positive airway pressure (CPAP). In eight patients with acute respiratory failure, the effects of 20 cm PEEP administered via CPPV and CPAP were compared. An esophageal balloon was used to calculate the transmural vascular pressures. The control values under mechanical ventilation with no PEEP (IPPV) for PaO₂ and QS/QT (FiO₂ being 1.0) were respectively 132±15 mmHg and 31±3%; CPPV gave a PaO₂ of 369±27 mmHg and QS/QT fo 14±1.6%, CPAP 365±18 mmHg and 18±1.3% respectively. The two different modes of ventilation (CPPV and CPAP) gave identical blood gas improvement through the same level of end expiratory transpulmonary pressure despite marked differences between absolute mean airway and esophageal pressures. Conversely, hemodynamic tolerance was very different from one technique to the other: CPPV depressed cardiac index from 3.4±0.3 to 2.4±0.2 l/min/m² as well as decreasing transmural filling pressures, suggesting a reduction in venous return. Conversely, filling pressures maintained at control values during CPAP and cardiac indexes were unchanged.Abbreviations IPPV intermittent positive pressure ventilation; mechanical ventilation (controlled mode) with zero end expiratory pressure (ZEEP) - CPPV continuous positive pressure ventilation: mechanical ventilation (controlled mode) with a positive pressure during expiration - CPAP continuous positive airway pressure; spontaneous ventilation with a positive pressure maintained during expiration - PEEP positive end expiratory pressure, whatever the ventilatory mode; spontaneous (CPAP) or mechanical (CPPV) Presented in part at the 44 th annual meeting of American College of Chest Physicians, Washington DC, October 1978     

Effects of pressure support ventilation and continuous positive airway pressure on diaphragm performance

Many patients who are on mechanical ventilation are on ventilator modes called pressure support ventilation (PSV) and continuous positive airway pressure (CPAP) particularly when they are being weaned. As the diaphragm is responsible for approximately 75% of breathing, it is important to promote diaphragm shortening to optimize weaning from mechanical ventilation. The purpose of our 1998 quasi-experimental study was to explore the effects of PSV and CPVP on diaphragm shortening. An animal model was utilized using four Sprague-Dawley rats from the same litter purchased from Sasco (Kansas City, USA). Also measured in this study were intrathoracic pressure (DeltaITP), positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, central venous pressure (CVP) and mean arterial pressure (MAP). Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed. These results support that higher levels CPAP may hinder diaphragmatic function thus prolong mechanical ventilation. The purpose of this pilot study was to explore the effects of PSV and CPAP on diaphragm shortening. Also measured were DeltaITP, positive inspiratory pressure, respiratory rate, tidal volume, end-tidal carbon dioxide, CVP and MAP. Pressure support was increased in increments of 5 cm H2O at CPAP levels of 0, 2 and 4 cm H2O. A direct assessment of diaphragm shortening was achieved through the adherence of a miniaturized ultrasonic sensor to the inferior surface of the middle costal surface of the right hemidiaphragm of four Sprague-Dawley rats. Limitations of this study included a small sample size, anaesthetized rats and abdominal dissection for insertion of the ultrasonic sensor. As PSV was increased, there was a decrease in MAP, CVP, respiratory rate and end-tidal CO2. When increasing levels of CPAP were added to PSV, a decrease in diaphragm shortening was observed.     

Noninvasive pressure support ventilation vs. continuous positive airway pressure in acute hypercapnic pulmonary edema

Objective This study compared noninvasive pressure support ventilation (NIPSV) and continuous positive airway pressure (CPAP) in patients with acute hypercapnic pulmonary edema with regard to resolution time.Design and setting Randomized prospective study in an emergency department.Patients and participants We randomly assigned 36 patients with respiratory failure due to acute pulmonary edema and arterial hypercapnia (PaCO₂ >45 mmHg) to NIPSV (n=18) or CPAP through a face mask (n=18).Measurements and results Electrocardiographic and physiological measurements were made over 36 h. There was no difference in resolution time defined as clinical improvement with a respiratory rate of fewer than 30 breaths/min and SpO₂ of 96% or more between CPAP and NIPSV groups. Arterial carbon dioxide tension was significantly decreased after 1 h of ventilation (CPAP, 60.5±13.6 to 42.8±4.9 mmHg; NIPSV, 65.7±13.6 to 44.0±5.5 mmHg); respective improvements were seen in pH (CPAP, 7.22±0.11 to 7.37±0.04; NIPSV, 7.19±0.11 to 7.38±0.04), SpO₂ (CPAP, 86.9±3.7% to 95.1±2.6%; NIPSV, 83.7±6.6% to 96.0±2.9%), and respiratory rate (CPAP, 37.9±4.5 to 21.3±5.1 breaths/min; NIPSV, 39.8±4.4 to 21.2±4.6 breaths/min). No significant differences were seen with regards to endotracheal intubation and in-hospital mortality.Conclusions NIPSV proved as effective as CPAP in the treatment of patients with acute pulmonary edema and hypercapnia but did not improve resolution time.     

持续气道正压-比例压力支持-自动管道补偿与双水平气道正压-压力支持通气两种模式撤机方法的比较

目的 :比较持续气道正压比例压力支持自动管道补偿 (CPAP PPS ATC)与双水平气道正压压力支持通气 (BIPAP PSV)两种模式撤机方法的结果。方法 :CPAP PPS ATC组 42例 ,BIPAP PSV组 40例 ,采用对照研究方法 ,比较两种通气模式、起始参数的调节、解决通气机依赖特点及撤机成功率。结果 :两种模式的撤机成功率无明显差异 (P>0 .0 5 ) ,两种模式均无人机对抗 ,CPAP PPS ATC模式较 BIPAP PSV模式对通气机依赖患者有更大的自主性 ,更容易实现撤机。结论 :BIPAP PSV为压力控制与自主呼吸相结合模式 ,CPAP PPS ATC为自主模式 ,CPAP PPS ATC是一种更好的机械通气撤机模式     

Danger of helmet continuous positive airway pressure during failure of fresh gas source supply

Objective To assess the behavior of different helmets after discontinuation of fresh gas flow by disconnection at the helmet inlet, flow generator, or gas source. Design and setting Randomized physiological study in a university research laboratory. Patients Five healthy volunteers. Intervention CPAP (FIO₂ 50%, PEEP 5 cmH₂O) delivered in random sequence with three different helmets: 4Vent (Rüsch), PN500 (Harol), CaStar (StarMed) with antisuffocation valve open or locked. For each helmet all three disconnections were randomly employed up to 4 min. Measurements and results During flow disconnection we measured: respiratory rate and tidal volume by respitrace; inspiratory and expiratory CO₂ concentration, and FIO₂ from a nostril; SpO₂ by pulse oxymetry. Independently of the site of disconnection we observed a fast increase in CO₂ rebreathing and minute ventilation, associated with a decrease in inspired O₂ concentration. In the absence of an operational safety valve, larger helmet size and lower resistance of the inlet hose resulted in slower increase in CO₂ rebreathing. The presence of the safety valve limited the rebreathing of CO₂, and the increase in minute ventilation but did not protect from a decrease in FIO₂ and loss of PEEP. Conclusions While the use of a safety valve proved effective in limiting CO₂ rebreathing, it did not protect from the risk of hypoxia related to decrease in FIO₂ and loss of PEEP. In addition to a safety antisuffocation valve, a dedicated monitoring and alarming systems are needed to employ helmet CPAP safely.     

Clinical review: Biphasic positive airway pressure and airway pressure release ventilation

This review focuses on mechanical ventilation strategies that allow unsupported spontaneous breathing activity in any phase of the ventilatory cycle. By allowing patients with the acute respiratory distress syndrome to breathe spontaneously, one can expect improvements in gas exchange and systemic blood flow, based on findings from both experimental and clinical trials. In addition, by increasing end-expiratory lung volume, as occurs when using biphasic positive airway pressure or airway pressure release ventilation, recruitment of collapsed or consolidated lung is likely to occur, especially in juxtadiaphragmatic lung legions. Traditional approaches to mechanical ventilatory support of patients with acute respiratory distress syndrome require adaptation of the patient to the mechanical ventilator using heavy sedation and even muscle relaxation. Recent investigations have questioned the utility of sedation, muscle paralysis and mechanical control of ventilation. Furthermore, evidence exists that lowering sedation levels will decrease the duration of mechanical ventilatory support, length of stay in the intensive care unit, and overall costs of hospitalization. Based on currently available data, we suggest considering the use of techniques of mechanical ventilatory support that maintain, rather than suppress, spontaneous ventilatory effort, especially in patients with severe pulmonary dysfunction.     

Noninvasive continuous positive airway pressure ventilation using a new helmet interface: a case-control prospective pilot study

Objective To evaluate the clinical efficacy of noninvasive continuous positive airway pressure ventilation (CPAP) using a new interface, constituted by a cephalic plastic helmet, in comparison with a standard facial mask.Design and setting A prospective pilot study with matched-control group, in the emergency department of a teaching hospitalPatients and methods Eleven consecutive adult patients with acute hypoxemic respiratory failure related to cardiogenic pulmonary edema (whether hypercapnic or not) were enrolled in the study, after failure of the initial medical treatment. Each patient treated with CPAP, using the helmet in addition to a standardized medical treatment, was matched with historical control-patient treated with CPAP using a standard facial mask, and selected by gender, age, and PaCO₂ levels on admission. Primary end points were improvements of gas exchanges and clinical parameters of respiratory distress. Tolerance was evaluated after each CPAP trial.Results The 22 patients and controls had similar characteristics at baseline. PaCO₂ levels, and clinical parameters improved similarly in both groups. No interface intolerance was reported whether using standard facial mask or the helmet. No complications were observed in either group. The helmet allowed CPAP administration for a longer period of time (p=0.045). In-hospital mortality was not different between the two groups.Conclusion Despite a high dead-space volume (9–15 l), this new helmet interface is an efficient alternative to standard face mask during CPAP, even in cases of severe respiratory acidosis and hypercapnia. It allows to provide long-duration CPAP, without any adverse events or clinical intolerance.