Comparison of the T-piece resuscitator with other neonatal manual ventilation devices: a qualitative review

Aim

To review the literature surrounding various aspects of T-piece resuscitator use, with particular emphasis on the evidence comparing the device to other manual ventilation devices in neonatal resuscitation.

Data sources

The Medline, EMBASE, Cochrane databases were searched in April 2011. Ongoing trials were identified using www.clinicaltrials.gov and www.controlled-trials.com. Additional studies from reference lists of eligible articles were considered. All studies including T-piece resuscitator use were eligible for inclusion.

Results

Thirty studies were included. There were two randomised controlled trials in newborn infants comparing the devices, one of which addressed short and intermediate term morbidity and mortality outcomes and found no difference between the T-piece resuscitator and self inflating bag. From manikin studies, advantages to the T-piece resuscitator include the delivery of inflating pressures closer to predetermined target pressures with least variation, the ability to provide prolonged inflation breaths and more consistent tidal volumes. Disadvantages include a technically more difficult setup, more time required to adjust pressures during resuscitation, a larger mask leak and less ability to detect changes in compliance.

Conclusions

There is a need for appropriately designed randomised controlled trials in neonates to highlight the efficacy of one device over another. Until these are performed, healthcare providers should be appropriately trained in the use of the device available in their departments, and be aware of its own limitations.     

Comparison of ventilation performance: standard resuscitation bag and the resuscitation bag controller

Clinical evaluation of ventilation performance during resuscitation is largely subjective. A mechanical device, the resuscitation bag controller (RC), which encircles the bag and allows controlled compression may improve the precision and accuracy of ventilation with manual resuscitation bags (MRB). We hypothesize that more precise, controlled pressure ventilation can be delivered with the RC, compared to the MRB. Prehospital (N = 13) and hospital personnel (N = 12) who routinely perform manual ventilation were randomized to either method of ventilation. Operators were instructed to ventilate an intubated adult mannequin. The percent of breaths delivered within a specified range, 800 to 1200 mL, was compared using simple regression analysis. The precision of tidal volume (TV) and peak airway pressure (PAP) was compared between methods and groups using the coefficient of variation. Comparison for significant differences between methods and groups in the number of breaths with a TV less than 800 mL and those with pressures greater than 30 cm H20 was performed using chi square or Fisher's exact test. There were no significant differences in the percent of acceptable breaths or mean TV delivered between methods or groups. The precision (i.e., reproducibility of the same value) of TV for both methods was best for hospital personnel. PAPS were less than or equal to 30 cm H2O for 93% of all breaths. Hospital personnel delivered a significantly greater percent of inadequate (less than 0.8 L) breaths, 19 versus 7.4%, and excessive pressure breaths, 9.2 versus 4.2%, when compared to prehospital personnel. We conclude that the resuscitation bag controller offers little advantage over standard bag resuscitation for adult resuscitation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of methods of bag and mask ventilation for neonatal resuscitation.

BACKGROUND: There are a variety of manual bagging devices used for neonatal resuscitation. To our knowledge, there has been no comparison of the ability of different operators to utilize such devices for the delivery of predetermined inspiratory and end-expiratory pressures. In addition, the use of prolonged inflation may be of benefit for infants who require bag and mask ventilation, and there has been no evaluation of the ability of a variety of operators to reliably deliver such breaths using currently available equipment. METHODS: We utilized a neonatal manikin (Laerdal Armonk, NY) with a functional larynx and lungs, and a clear cushioned mask (Owens-BriGam, Morganton, NC). We studied a latex-free disposable anesthesia type bag (Model 5126 Vital Signs, Totawa, NJ), a Jackson-Rees (JR) type anesthesia bag (Model E191 Anesthesia Associates, San Marcos, CA) fitted with a Norman elbow and a flow-control tail-piece (Dupaco, Oceanside, CA), and the Neopuff (Fisher and Paykel, Auckland, New Zealand), an FDA approved mechanical device that is flow-controlled and pressure-limited, specifically designed to facilitate neonatal resuscitation. The ventilating pressures were continuously recorded throughout the process. We evaluated neonatal nurses, neonatal nurse practitioners, neonatal staff and fellows, pediatric residents and neonatal respiratory therapists. RESULTS: The peak inspiratory pressure (PIP) was significantly different between operators using either anesthesia bag, P<0.001. Similar results were found for positive end-expiratory pressure (PEEP) with a significant difference among the operator groups, P<0.001. All the differences in post hoc analysis were between the therapists and the other groups, P<0.05. Therapists produced significantly higher pressures than the other groups for both PIP and PEEP (P<0.001). The PIP was similar for all groups using the Neopuff device. The PIP and PEEP delivered by the Neopuff differed from the other two devices independent of the operators (P<0.05). On post hoc analysis, there was a significant difference between the disposable anesthesia bag and Neopuff for both PIP and PEEP for the therapists, whereas among the non-therapists, there was a difference in PIP with the JR device producing a greater PIP (26.6+/-3.8 cmH(2)O) compared with the Neopuff and disposable anesthesia bag (24.8+/-1.1 cmH(2)O, 24.8+/-4.3 cmH(2)O). The level of PEEP was significantly different among all three devices for the non-therapists (1.3+/-1.6 cmH(2)O, Disposable; 2.9+/-1.2 cmH(2)O, JR; 4.7+/-0.5 cmH(2)O, Neopuff; P<0.05). Only the therapists were able to consistently deliver PEEP with the anesthesia bags, whereas all operators could generate the target PEEP with the Neopuff (P<0.05). We compared the pressure delivered during the first second to the pressure delivered during the fifth second during prolonged 5-s inflations. The absolute differences between the first and fifth second for the Neopuff versus the anesthesia bags were significantly different with a median of 7.1 cmH(2)O for the anesthesia bags compared with 0.2 cmH(2)O for the Neopuff, P<0.001, reflecting the difficulty in obtaining and maintaining the target inflation pressures. CONCLUSIONS: Our experience suggests that the Neopuff, a purpose-built neonatal resuscitator ventilator, facilitates the delivery of the desired airway pressures while maximizing the operators ability to obtain and maintain a patent airway, and facilitates the delivery of prolonged inflations. Further research is required to determine the clinical benefit of end-expiratory pressure and prolonged inflations in neonatal resuscitation.     

Comparison of automated and manual ventilation in a prehospital pediatric model

Objective. Portable transport ventilators (TV) and demand valves (DV) may be effective and easy-to-use alternatives to bag-valve (BV) for prehospital ventilation of adults. The purpose of the study was to determine whether such devices maintain arterial blood gases and airway pressures similar to those for BV in a pediatric swine model. Method. This study was a prospective, randomized, crossover design using immature swine (9.6 ± 0.9 kg) to model ventilation in small children. Anesthetized, intubated, paralyzed, and cannulated animals were ventilated initially on standard mechanical hospital ventilation (HV). They were then assigned in random order to 10-minute intervals of ventilation using BV, TV, low-frequency jet ventilation (JV), and DV. Data were analyzed using repeated-measures ANOVA and Tukey multiple comparisons (alpha = 0.05). Results. The PaO₂ exceeded 90 mm Hg for all animal/ventilation combinations. Blood PaCO₂ was lower for BV and DV than it was for TV, JV, or HV. In contrast, blood pH was higher for BV and DV than it was for TV, JV, or HV. Peak airway pressure was higher for BV than it was for HV, TV, or JV; it was lower for JV than it was for HV, TV, or BV. Conclusion. This animal model suggests that automated TV and JV may provide more effective ventilation of children than do manual BV or DV devices. Although promising, these findings require application in children under prehospital emergent conditions.     

Evaluation of a novel paediatric self-inflating bag to improve accuracy of tidal volumes delivered during simulated advanced paediatric resuscitation

Objective

The aim of the study is to compare the accuracy of manually delivered target tidal volumes (TVs) with the conventional paediatric self-inflating bags (CPBs) versus the novel paediatric self-inflating bags (NPBs) during simulated advanced paediatric resuscitation.

Methods

Before the trial begun, four target TV ranges were established using the Broselow™ Tape as a reference: 36-70 ml for 6-10 kg, 60-105 ml for 10-15 kg, 90-168 ml for 15-24 kg and 144-210 ml for 24-30 kg. An NPB with four surface marks matching the target TV ranges was prepared. Senior medical students (N = 73) were enrolled. After 1 week of training in TV delivery with both CPB and NPB, subjects participated in a test simulation. Using the CPB and NPB in a random cross-over design, participants delivered 10 ventilations to test lungs connected to gas flow analysers for the randomly assigned target TV ranges.

Results

Each of the 730 values for TV and peak inspiratory pressures (PIPs) delivered by CPB and NPB were analysed. The proportion of accurate TV delivery was higher with NPB than with CPB: 84.2% versus 45.9% for 36-70 ml, 93.2% versus 42.7% for 60-105 ml, 96.0% versus 70.3% for 90-168 ml and 91.2% versus 62.6% for 144-210 ml, respectively (all p < 0.0001). Compared with NPB, CPB delivery was more varied and was more frequently out of range. There were no significant differences in PIP between the CPB and NPB.

Conclusions

NPB is useful as a ventilation device for the accurate delivery of TV to small children of varying weights.     

Comparison of ventilation and cardiac compressions using the Impact Model 730 automatic transport ventilator compared to a conventional bag valve with a facemask in a model of adult cardiopulmonary arrest

PURPOSE: To determine the performance of two person CPR on an instrumented manikin by registered nurses using conventional bag valve mask (BVM) ventilation or the Impact Model 730 automatic transport ventilator (Impact 730, Impact Instrumentation, Inc., West Caldwell, NJ) in CPR mode using a face mask. DESIGN: Randomized crossover quasi-experimental. SETTING: Laboratory simulation. SUBJECTS: Twenty-eight registered nurses trained in performing adult cardiopulmonary resuscitation (CPR). INTERVENTIONS: Basic Life Support was provided by subjects using a conventional bag valve mask (BVM) ventilation or mask ventilation with an automatic transport ventilator, the Impact 730, which incorporates a metronome to facilitate chest compression timing. Subjects alternated performing 4min of CPR using the BVM or Impact 730 to deliver breaths with a mask while the other subject performed compressions. MEASUREMENTS AND MAIN RESULTS: Flow, volume and pressure were measured using a pneumotachograph and pressure transducer, and ease of use was measured using a 10cm visual analogue scale. There was no statistical or clinical difference between the actual and recommended tidal lung volume (mean+/-S.D.) delivered by the Impact 730 (-120.4+/-91.5ml) versus the BVM (-119.8+/-187.3+/-ml). Ventilation with the BVM resulted in more (137.7+/-143.9ml) air per breath passing through the simulated lower esophageal sphincter compared to the Impact 730 (14.0+/-16.8ml, p<0.05). The reduced mask leak per breath with the Impact 730 (176.1+/-98.3ml) compared to the BVM (367.6+/-337.7ml, p<0.05) is likely to have resulted from the subject being able to manage the mask with two rather than one hand and is reflected in the higher ease of use score on a 10cm visual analogue scale with the Impact 730 (8.06+/-1.35cm) versus the BVM (6.46+/-2.46cm, p<0.05). Subjects tended to deliver slightly more compressions and breaths when using the BVM. CONCLUSION: Compared to the BVM, the Impact 730 is as effective, easier to use and limits the amount of gas entering the stomach when used during adult CPR in a simulated setting.     

Comparison of ventilation and chest compression performance by bystanders using the Impact Model 730 ventilator and a conventional bag valve with mask in a model of adult cardiopulmonary arrest

"Bystanders" or lay persons are typically the first caregivers to attend to a victim of out-of-hospital cardiopulmonary arrest. Astronaut crew medical officers (CMO) play a similar role to bystanders aboard the International Space Station (ISS). Studies have demonstrated the importance of bystander cardiopulmonary resuscitation (BCPR) for patient survival before the arrival of emergency medical care. Recent apprehension from bystanders about the threat of contracting communicable diseases during BCPR, however, has led to the consideration of other ventilation systems such as the bag-valve mask (BVM) and automatic transport ventilators (ATV). BVM use is called for during CPR aboard the ISS. This study evaluated the ventilation and compression performance of 40 basic CPR-trained bystanders using either a BVM (adult-sized self-inflating bag with face mask) or an ATV (Model 730 ventilator (M730), Impact Instrumentation, Inc., West Caldwell, NJ). Each two-bystander team gave BCPR to a simulated cardiopulmonary arrest victim using the 2-breath/15-compression cycle for 4 min and then switched roles for another 4-min interval. Compared to BVM use, the M730 led to significantly (p<0.05) lower number of breaths, smaller tidal volumes, airway flows, airway pressures, volume of gas entering the stomach per breath and chest compressions for the 4-min period. The M730 also enabled a bystander to meet the recommendation of 4-breath and compression cycles per minute as per Guidelines 2000. Lastly, ease-of-use scores were significantly higher for the M730 compared to the BVM. Overall, the data suggest that the M730 improves the quality of performance for a bystander performing BCPR.     

Comparison of high-frequency jet ventilation to conventional ventilation in adults with respiratory distress syndrome

Sixteen patients with acute respiratory failure (ARF) were studied. In group I (12 patients, 15 explorations) patients were treated with continuous positive pressure ventilation (CPPV) during conventional ventilation (CV), pulmonary lesions (PL) were severe (Q_sp/Q_t=0.24–0.16 with PEEP=14±7 cm H₂O) and high-frequency jet ventilation (HFJV) was performed without spontaneous ventilation (SV). In group II (5 patients, 12 explorations) patients were treated with intermittent mandatory ventilation (IMV) during CV, PL were moderate (Q_sp/Q_t=0.13–0.05 with PEEP=8±3 cm H₂O) and HFJV was performed with SV. In both groups, frequency was 120 c/mn and I:E ratio=1:2. The cannula size, the driving pressure and the PEEP (water column) were progressively adapted to obtained the same blood gases as those observed during CV, FIO₂ being the same. Results on HFJV were compared to CV. In both groups there were no differences between PaCO₂, PaO₂, FIO₂, Q_sp/Q_t during CV and HFJV. In group I peak airway pressure (PAWP), mean artery pressure (MAP), heart rate (HR), transmural mean pulmonary and wedge pressure (MPAP_tm, PWP_tm) were not different. Mean airway pressure (MAWP), PEEP and pleural pressure (PP) were higher, cardiac index (CI) was lower. In group II, PP, CI, MAP, HR, MPAP_tm, MPWP_tm were not different. PAWP was lower, MAWP and PEEP were higher. We conclude that during HFJV it is possible to obtain the same blood gas as during CV, but HFJV without CV may not be indicated in patients with severe PL, because circulatory impairment is higher.     

Necrotizing tracheobronchitis: complication of mechanical ventilation in an adult

A 51-year-old woman had localized interstitial pneumonia that rapidly progressed to involve all lung fields. After 9 days of conventional mechanical ventilation, pneumothorax developed in the presence of an obstruction of the right main bronchus. Bronchoscopy and endobronchial biopsies revealed NTB involving the tracheobronchial tree distal to the tip of the endotracheal tube, with complete obstruction of the right main bronchus by hard, eschar-like material. Tracheal mucosa proximal to the tip of the endotracheal tube was normal. Subsequent bronchoscopy, 20 days later, showed marked resolution of NTB. Though a frequent complication of mechanical ventilation in the neonate, NTB as a complication of conventional mechanical ventilation has not previously been recognized in an adult. Necrotizing tracheobronchitis should be suspected in adults who have had mechanical ventilation and who are experiencing ventilatory difficulties, after routine problems have been treated or excluded.     

Comparison of high-frequency jet ventilation with conventional mechanical ventilation in saline-lavaged rabbits

A surfactant-depletion lung-injury model was produced in 37 New Zealand white rabbits by saline lavage. During the next 2 to 3 h, rabbits were ventilated with conventional mechanical ventilation (CMV, group 1), high-frequency jet ventilation (HFJV, group 2), or CMV for 1 h followed by HFJV for 2 h (CMV/HFJV, group 3). Survival until planned termination of the protocol was 56%, 77%, and 63% in groups 1, 2 and 3, respectively. Causes of early demise were usually pneumothorax or metabolic acidosis. There were no statistically significant differences among the groups with respect to survival, incidence of pneumothorax or metabolic acidosis. Arterial oxygenation was more efficient with HFJV (group 2) (P[A-a]O2 = 372 +/- 51 torr [mean +/- SE] at 2 h) than with CMV (group 1) (P[A-a]O2 = 512 +/- 18 torr at 2 h, p less than .01). Furthermore, oxygen gas exchange in 3 of 5 group 3 rabbits improved after institution of HFJV. In contrast to previous findings with high-frequency oscillation (HFO), there were no qualitative histologic differences between lungs ventilated with HFJV vs. CMV. Thus, although HFJV produced more efficient gas exchange in this model, it did not improve pulmonary pathology. HFO may be preferable to HFJV in infant respiratory distress syndrome.     

Comparison of automated nucleic acid extraction methods with manual extraction

Automated nucleic acid extractors can improve workflow and decrease variability in the clinical laboratory. We evaluated Qiagen EZ1 (Valencia, CA) and bioMérieux (Durham, NC) easyMAG extractors compared with Qiagen manual extraction using targets and matrices commonly available in the clinical laboratory. Pooled samples were spiked with various organisms, serially diluted, and extracted in duplicate. The organisms/matrices were Bordetella pertussis/bronchoalveolar lavage, herpes simplex virus II/cerebrospinal fluid, coxsackievirus A9/cerebrospinal fluid, BK virus/plasma, and Mycoplasma pneumoniae/endotracheal tube samples. Extracts were amplified in duplicate using real-time PCR assays, and amplification of the target at a cycle threshold of 35 using the manual method was used for comparison. Amplification efficiency of nucleic acids extracted by automated methods was similar to that by the manual method except for a loss of efficiency for M. pneumoniae in endotracheal tube samples. The EZ1 viral kit 2.0 gave better results for coxsackievirus A9 than the EZ1 viral kit version 1.0. At the lowest limit of detection (past a cycle threshold of 35), the easyMAG was more likely to produce amplifiable nucleic acid than were either the EZ1 or manual extraction. Operational complexity, defined as the number of manipulations required to obtain an extracted sample, was the lowest for the easyMAG. The easyMAG was the most expensive of the methods, followed by the EZ1 kit and manual extraction.     

A strategy to optimise the performance of the mouth-to-bag resuscitator using small tidal volumes: effects on lung and gastric ventilation in a bench model of an unprotected airway

When ventilating an unintubated patient with a standard adult self-inflating bag, high peak inspiratory flow rates may result in high peak airway pressures with subsequent stomach inflation. In a previous study we have tested a newly developed mouth-to-bag-resuscitator (max. volume, 1500 ml) that limits peak inspiratory flow, but the possible advantages were masked by excessive tidal volumes. The mouth-to-bag-resuscitator requires blowing up a balloon inside the self-inflating bag that subsequently displaces air, which then flows into the patient's airway. Due to this mechanism, gas flow and peak airway pressures are reduced during inspiration when compared with a standard bag-valve-mask-device. In addition, the device allows the rescuer to use two hands instead of one to seal the mask on the patient's face. The purpose of the present study was to assess the effects of the mouth-to-bag-resuscitator, which was modified to produce a maximum tidal volume of 500 ml, compared with a paediatric self-inflating bag (max. volume, 380 ml), and a standard adult self-inflating bag (max. volume, 1500 ml) in an established bench model simulating an unintubated patient with respiratory arrest. The bench model consisted of a face mask, manikin head, training lung (lung compliance, 100 ml/0.098 kPa (100ml/cm H2O); airway resistance, 0.39 kPa/(l s) (4 cm H2O/(l s)), and a valve simulating lower oesophageal sphincter pressure, 1.47 kPa (15 cm H2O). Twenty critical care nurses volunteered for the study and ventilated the manikin for 1 min with a respiratory rate of 20 min(-1) with each ventilation device in random order. The mouth-to-bag-resuscitator versus paediatric self-inflating bag resulted in significantly (P < 0.05) higher lung tidal volumes (302 +/- 41 ml versus 233 +/- 22 ml), and peak airway pressure (10 +/- 1 cm H2O versus 9 +/- 1 cm H2O), but comparable inspiratory time fraction (28 +/- 5% versus 27 +/- 5%, Ti/Ttot), peak inspiratory flow rate (0.6 +/- .01 l/s versus 0.6 +/- 0.2 l/s), and stomach inflation (149 +/- 495 ml/min versus 128 +/- 278 ml/min). In comparison with the adult self-inflating bag, there was significantly (P < 0.05) less gastric inflation (3943 +/- 4896 ml/min versus 149 +/- 495 ml/min versus 128 +/- 278 ml/min, respectively) with both devices, but the standard adult self-inflating bag had significantly higher lung tidal volumes (566 +/- 77 ml), peak airway pressure (13 +/- 1 cm H2O), and peak inspiratory flow rate (0.8 +/- 0.11 l/s). In conclusion, comparing the mouth-to-bag-resuscitator with small tidal volumes versus the paediatric self-inflating-bag during simulated ventilation of an unintubated patient in respiratory arrest resulted in comparable marginal stomach inflation, but significantly reduced the likelihood of gastric inflation compared to the adult self-inflating-bag. Lung tidal volumes were improved from approximately 250 ml with the paediatric self-inflating-bag to approximately 300 ml with the mouth-to-bag-resuscitator.     

SQA ⅡB精液常规检测与传统手工检测的比较

目前多数医院中精液常规检测都用手工法,人为影响因素较大,因而影响到不同实验室间结果的可比性。本研究采用SQA(Sperm Quality Analyzer)IIB精液常规自动分析仪,为了评估SQA IIB精液常规分析仪的检测效能,将其检测结果与传统的手工显微镜检结果相比较,探讨SQAIIB精液常规自动分析仪的临床应用价值。资料和方法一、一般资料收集2003年1月～2005年8月间来我院就诊的男性患者453例,年龄19～48岁,平均31岁。受检者均禁欲3～5d后应用手淫方法在医院内采取精液,收集于干净的尿杯中,10min内送检。二、检测方法1.仪器检测:SQA IIB精液常…     

膨肺联合呼气相挤压胸廓法在格林-巴利综合征机械通气患者中的应用

目的 探讨膨肺联合呼气相挤压胸廓法(manual hyperinflation with thoracic squeeze technique ,MHTST)在格林-巴利综合征机械通气患者中的应用效果。 方法 选取2015年10月-2018年10月我院呼吸重症监护病房中的15例行机械通气的格林-巴利综合征患者,采用随机交叉试验对研究对象进行MHTST、膨肺(manual hyperinflation,MH)排痰,比较实施2种排痰法后患者的收缩压、舒张压、心率、血氧饱和度、潮气量、平台压、静态顺应性、痰液排出量。 结果 实施2种排痰法后患者的血流动力学和呼吸力学指标比较,差异均无统计学意义(P＞0.05),实施MHTST后患者平均排痰量高于MH法(t=-7.965,P＜0.001)。 结论 对于机械通气支持的格林-巴利综合征患者,MHTST和MH排痰法对血流动力学及呼吸力学的影响相似,但MHTST的排痰法效果优于MH法。     

The effects of an automatic,low pressure and constant flow ventilation device versus manual ventilation during cardiovascular resuscitation in a porcine model of cardiac arrest

Background

Cardiac arrest is an important cause of mortality. Cardiopulmonary resuscitation (CPR) improves survival, however, delivery of effective CPR can be challenging and combining effective chest compressions with ventilation, while avoiding over-ventilation is difficult. We hypothesized that ventilation with a pneumatically powered, automatic ventilator (Oxylator^®) can provide adequate ventilation in a model of cardiac arrest and improve the consistency of ventilations during CPR.

Methods/results

Twelve pigs (∼40 kg, either sex) underwent 3 episodes each of cardiac arrest and resuscitation consisting of 30 s of untreated ventricular fibrillation, followed by 5 min of CPR, defibrillation, and ∼30 min of recovery. During CPR in each episode, pigs were ventilated in 1 of 3 ways in random balanced order: manual ventilation using AMBU bag (12 breaths/min), low pressure Oxylator^® (maximum airway pressure 15 cmH₂O with 20 L/min constant flow in automatic mode [Ox15/20]), or high pressure Oxylator^® (maximum airway pressure 20 cmH₂O with 30 L/min constant flow in automatic mode [Ox20/30]). During CPR, both Ox15/20 and Ox20/30 resulted in higher levels of positive end expiratory pressure than manual ventilation. Ox15/20 ventilation also resulted in higher arterial pCO₂ than manual ventilation. Ox20/30 ventilation yielded higher arterial pO₂ and a lower arterial–alveolar gradient than manual ventilation. All pigs were successfully defibrillated, and no measured haemodynamic variables were different between the groups.

Conclusion

Ventilation with an automatic ventilation device during CPR is feasible and provides adequate ventilation and comparable haemodynamics when compared to manual bag ventilation.     

慢性阻塞性肺疾病机械通气患者两种不同通气模式的比较

目的探讨适应性支持通气（ASV）在慢性阻塞性肺疾病（COPD）机械通气患者中的应用。方法24例存在自主呼吸行机械通气的COPD患者随机分成两组,一组先使用辅助／控制通气（A／C）模式后改为ASV模式,另一组先使用A／C模式后改为同步间歇指令通气联合压力支持通气（SIMV＋PSV）模式,采用对照性研究方法,比较前后两种通气模式对患者的呼吸力学、血流动力学和血气分析的影响,以及两组间的有创通气时间、机械通气总时间、撤机成功率及调机次数。结果从A／C模式改为ASV后患者的呼吸频率（RR）、气道峰压（Pp）、平均气道压（Pro）、气道闭合压（P0．1）和浅快呼吸指数（RSB）下降,潮气量（VT）和肺顺应性（C）上升（P〈0．01）;从A／C模式改为SIMV＋PSV后RR、Pp、Pm、P0.1和RSB下降（P〈0．01）。两组其余呼吸力学、血流动力学及血气分析指标变更模式前后差异均无统计学意义,两组之间的有创通气时间、机械通气总时间、撤机成功率差异无统计学意义,但是ASV组的调机次数明显少于SIMV＋PSV组（8．5±2．2vs13．1±3．1,P〈0．01）。结论ASV和SIMV＋PSV与A／C比较能在一定程度上降低呼吸负荷,保护肺组织。运用于撤机时两种模式效果无明显差别,但ASV操作相对简单,适合于临床医师使用。