Timing of recovery of lung function after severe hypoxemic respiratory failure in children

Objective: To describe the timing of recovery of lung function after severe acute hypoxemic respiratory failure (AHRF) in children. Design: A serial observational follow-up study of clinical and lung function measurements up to 53 months after acute illness. Setting: University pediatric intensive care unit in a national children's hospital. Patients: Five critically ill children aged 5–14 years. Interventions: None Results: Clinical recovery: each patient required a 3–5 month convalescence before being able to attend full-time school because of lethargy and dyspnea. All patients developed wheeze 3–12 months after illness and four received long-term bronchodilator therapy. Lung function recovery: for both the forced vital capacity (FVC) and forced vital capacity in the first second (FEV₁) four patients had abnormally low values, regaining only 60–70 % of predicted values for their height and sex, and all of this improvement had occurred by 6–12 months after illness. Beyond this interval, patients remained on their same FVC and FEV₁ centile. FEV₁/FVC ratios were consistently within the normal range, indicating a predominantly restrictive defect. Changes in peak expiratory flow exhibited a time course of improvement similar to the other lung function tests. Conclusion: In children, pulmonary recovery after severe AHRF may occur for 6–12 months. A 1-year follow-up could offer a rational single point for assessment of outcome and long-term counselling of child and parents. Received: 10 November 1997 Accepted: 20 January 1998     

Effects of dynamic ventilatory factors on ventilator-induced lung injury in acute respiratory distress syndrome dogs

BACKGROUND:

Mechanical ventilation is a double-edged sword to acute respiratory distress syndrome (ARDS) including lung injury, and systemic inflammatory response high tidal volumes are thought to increase mortality. The objective of this study is to evaluate the effects of dynamic ventilatory factors on ventilator induced lung injury in a dog model of ARDS induced by hydrochloric acid instillation under volume controlled ventilation and to investigate the relationship between the dynamic factors and ventilator-induced lung injuries (VILI) and to explore its potential mechanisms.

METHODS:

Thirty-six healthy dogs were randomly divided into a control group and an experimental group. Subjects in the experimental group were then further divided into four groups by different inspiratory stages of flow. Two mL of alveolar fluid was aspirated for detection of IL-8 and TNF-α. Lung tissue specimens were also extracted for total RNA, IL-8 by western blot and observed under an electronic microscope.

RESULTS:

IL-8 protein expression was significantly higher in group B than in groups A and D. Although the IL-8 protein expression was decreased in group C compared with group B, the difference was not statistically significant. The TNF-α ray degree of group B was significantly higher than that in the other groups (P<0.01), especially in group C (P>0.05). The alveolar volume of subjects in group B was significantly smaller, and cavity infiltration and cell autolysis were marked with a significant thicker alveolar septa, disorder of interval structures, and blurring of collagenous and elastic fiber structures. A large number of necrotic debris tissue was observed in group B.

CONCLUSION:

Mechanical ventilation with a large tidal volume, a high inspiratory flow and a high ventilation frequency can cause significant damage to lung tissue structure. It can significantly increase the expression of TNF-α and IL-8 as well as their mRNA expression. Furthermore, the results of our study showed that small tidal ventilation significantly reduces the release of pro-inflammatory media. This finding suggests that greater deterioration in lung injury during ARDS is associated with high inspiratory flow and high ventilation rate.KEY WORDS: Acute respiratory distress syndrome, Dynamic factors, Inspiratory flow, Ventilator-induced lung injury     

小儿急性低氧性呼吸衰竭呼吸支持相关预后差异及影响因素

目的 探讨26家医院小儿重症监护室(PICU)患者呼吸支持相关的预后之差异及影响因素.方法 多中心前瞻性临床协作研究,研究时间为2005年12月至2006年11月连续12个月,研究对象为29 d至15周岁的PICU患儿.患儿纳入后记录其基本情况、疾病诊断、治疗及预后等数据,汇总后分析不同PICU其患者预后及呼吸治疗的差异.结果 在研究期间,26家PICU共收治危重病例11521例,占PICU收治患者总数的70%,不同单位该比例从14%到98%.26家单位共纳入小儿低氧性呼吸衰竭(AHRF)病例461例,患病率4%,各单位AHRF患病率中位值4.7%(Qr:2.4%～7.1%).AHRF总病死率41.6%,26家PICU病死率中位值39.8%(四分位数间距22%～57%).AHRF病死率在大学附属医院低于非大学附属医院(37%vs.46%,x~2=4.16,P:0.04),经济发达地区低于欠发达地区医院(38%vs.46%,x~2=3.1,P=0.08).结论 我国不同地区及不同类别医院PICU危重病例及AHRF呼吸支持相关的预后存在较大差异.PICU所在医院的学术背景及地区经济发展水平是影响患者预后的两个重要原因.在开展提高PICU的呼吸支持治疗水平和AHRF生存率的干预性研究设计中应予考虑.     

The impact of the initial ventilatory strategy on survival in hematological patients with acute hypoxemic respiratory failure

Purpose

The aim of this study was to assess the impact of the 3 types of initial respiratory support (noninvasive positive pressure ventilation vs invasive positive pressure ventilation vs supplemental oxygen only) in hematological patients with acute hypoxemic respiratory failure (ARF).

Materials and Methods

This study is a retrospective analysis of a cohort of hematological patients admitted to the intensive care unit (ICU) of a tertiary care hospital between January 1, 2002, and June 30, 2006.

Results

One hundred thirty-seven hematological patients were admitted at the ICU with ARF (defined as Pao₂/Fio₂ <200): within the first 24 hours, 24 and 67 patients received noninvasive positive pressure ventilation and invasive positive pressure ventilation, respectively, and 46 received supplemental oxygen only. Intensive care unit mortality in the 3 patient categories was 71%, 63%, and 32%, respectively (P = .001), and in-hospital mortality was 75%, 80%, and 47%, respectively (P = .001). In multivariate regression analysis, increasing cancer-specific severity-of-illness score upon admission and more organ failure after 24 hours of ICU admission, but not the type of initial respiratory support, were significantly associated with ICU or in-hospital mortality.

Conclusions

Intensive care unit and in-hospital mortality in our population of hematological patients with hypoxemic ARF was determined by severity of illness and not by the type of initial respiratory support.     

气管内肺通气对急性肺损伤羊通气功能的影响

气管内肺通气（ＩＴＰＶ）是一种新的持续正压通气方式。本研究应用直流和反流两种气管插管内导管进行ＩＴＰＶ，并与压力控制通气（ＰＣＶ）进行比较。结果显示：直流ＩＴＰＶ的ＰａＣＯ２下降０．６９～０．９３ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ，Ｐ＜０．０５），生理死腔（ＶＤ）减少０．８ｍｌ／ｋｇ；反流ＩＴＰＶ的ＰａＣＯ２下降１．０７～１．３３ｋＰａ（Ｐ＜０．０１），ＶＤ减少１．０ｍｌ／ｋｇ；在维持ＰａＣＯ２５．０７±０．４４ｋＰａ条件下，反流ＩＴＰＶ气管内吸气压峰压（ＰＩＰ）下降３３％，平均气道压（Ｐａｗ）下降约５０％；ＰａＯ２和血流动力学参数均无显著变化（Ｐ＞０．０５）。提示：ＩＴＰＶ通过减少生理死腔使通气效率提高，可以用较低的ＰＩＰ和Ｐａｗ维持肺的正常气体交换；反流ＩＴＰＶ比直流ＩＴＰＶ显示更有效的通气效率     

Effects of ventilatory pattern on experimental lung injury caused by high airway pressure

OBJECTIVE: To determine the influence of clinician-adjustable ventilator settings on the development of ventilator-induced lung injury, as assessed by changes in gas exchange (Pao2), compliance, functional residual capacity, and wet weight to dry weight ratio. DESIGN: Randomized in vivo rabbit study. SETTING: Hospital research laboratory. SUBJECTS: Forty-four anesthetized, mechanically ventilated adult rabbits. INTERVENTIONS: Ventilation for 2 hrs with pressure control ventilation at 45 cm H2O, Fio2 = 0.6, and randomization to one of five ventilatory strategies using combinations of positive end-expiratory pressure (3 or 12 cm H2O), inspiratory time (0.45, 1.0, or 2.0 secs), and frequency (9 or 23/min). MEASUREMENTS AND MAIN RESULTS: Among the ventilator strategies applied, PEEP at 12 cm H2O (elevated positive end-expiratory pressure) and inspiratory time at 0.45 secs (reduced inspiratory time) best preserved Pao2 (p <.003) and compliance (p <.035). During injury development, two consistent changes were observed: Tidal volume increased, and airway pressure waveform was transformed by extending the time to attain target pressure. CONCLUSIONS: In this preclinical model, lung injury was attenuated by decreasing inspiratory time. As lung injury occurred, tidal volume increased and airway pressure waveform changed.     

重症颅脑损伤病人的呼吸功能监护

综述了重型颅脑损伤后呼吸功能的监测指标以及保持呼吸道通畅、机械通气的方法及护理。     

雷公藤内酯醇对大鼠重症急性胰腺炎肺损伤的影响

目的 探讨雷公藤内酯醇对重症急性胰腺炎(SAP)肺损伤大鼠的保护作用及其可能机制.方法 将36只雄性Wistar大鼠随机分为假手术组(sham组)、模型组和雷公藤内酯醇处理组(Tri组)3组,每组6只.sham组仅行剖腹术;Tri组和模型组采用牛磺胆酸钠胰胆管逆行注射法复制SAP肺损伤模型,然后分别腹腔注射雷公藤内酯醇0.2 mg/kg或等量生理盐水.制模后6 h处死动物,取肺组织测定肺组织肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)的mRNA表达、蛋白含量及核转录因子-κB(NF-κB)活性.结果 与sham组比较,模型组肺组织TNF-α mRNA与IL-1β mRNA表达及蛋白含量、NF-κB活性均显著升高;与模型组比较,Tri组上述指标均明显降低,差异均有统计学意义(P均<0.01).结论 雷公藤内酯醇对SAP肺损伤大鼠具有一定保护作用,与抑制NF-κB活性进而下调TNF-α、IL-1β等炎症因子表达有关.     

重症颅脑损伤病人的呼吸功能监护

综述了重型颅脑损伤后呼吸功能的监测指标以及保持呼吸道通畅、机械通气的方法及护理。     

Partitioning the work-sparing effects of partial ventilatory support in airflow obstruction

Sweeping conclusions regarding the utility or nonutility of elevating expiratory pressure are not warranted. The effects of manipulating airway pressure in the setting of airflow obstruction depend heavily on the nature and severity of disease, as well as on the presence of airflow limitation during tidal breathing.     

Partitioning the work-sparing effects of partial ventilatory support in airflow obstruction

Sweeping conclusions regarding the utility or nonutility of elevating expiratory pressure are not warranted. The effects of manipulating airway pressure in the setting of airflow obstruction depend heavily on the nature and severity of disease, as well as on the presence of airflow limitation during tidal breathing.     

高压氧联合呼吸训练对颈脊髓损伤患者肺功能的影响

目的:观察高压氧联合呼吸训练对颈脊髓损伤患者肺功能的影响。方法:选取2018年3月—2019年5月在我院住院的颈脊髓损伤患者共60例,用随机数字表法将上述60例患者随机分为对照组和观察组(每组各30例),对照组给予常规药物、康复治疗,并给予PT呼吸训练每日1次,观察组在对照组治疗的基础上同时给予高压氧治疗,每日1次,分别于治疗前及治疗4周后检查肺功能,重点评估用力肺活量(FVC),第一秒用力呼气容积(FEV1),最大通气量(MVV)的变化。结果:与治疗前比较,对照组的FVC、FEV1、MVV分别增加了0.45±0.41L、0.27±0.36L、16.53±22.06L/min,FVC%pred、FEV1%pred、MVV%pred分别提高了11.33±9.41%、8.85±10.38%、12.78±16.77%;观察组治疗前后FVC、FEV1、MVV分别增加了1.20±0.39L、0.86±0.29L、42.40±23.81L/min,FVC%pred、FEV1%pred、MVV%pred分别提高了24.27±7.70%、24.27±7.07%、33.47±19.75%。治疗前后比较,...     

Short-term effects of noisy pressure support ventilation in patients with acute hypoxemic respiratory failure

Introduction

This study aims at comparing the very short-term effects of conventional and noisy (variable) pressure support ventilation (PSV) in mechanically ventilated patients with acute hypoxemic respiratory failure.

Methods

Thirteen mechanically ventilated patients with acute hypoxemic respiratory failure were enrolled in this monocentric, randomized crossover study. Patients were mechanically ventilated with conventional and noisy PSV, for one hour each, in random sequence. Pressure support was titrated to reach tidal volumes approximately 8 mL/kg in both modes. The level of positive end-expiratory pressure and fraction of inspired oxygen were kept unchanged in both modes. The coefficient of variation of pressure support during noisy PSV was set at 30%. Gas exchange, hemodynamics, lung functional parameters, distribution of ventilation by electrical impedance tomography, breathing patterns and patient-ventilator synchrony were analyzed.

Results

Noisy PSV was not associated with any adverse event, and was well tolerated by all patients. Gas exchange, hemodynamics, respiratory mechanics and spatial distribution of ventilation did not differ significantly between conventional and noisy PSV. Noisy PSV increased the variability of tidal volume (24.4 ± 7.8% vs. 13.7 ± 9.1%, P <0.05) and was associated with a reduced number of asynchrony events compared to conventional PSV (5 (0 to 15)/30 min vs. 10 (1 to 37)/30 min, P <0.05).

Conclusions

In the very short term, noisy PSV proved safe and feasible in patients with acute hypoxemic respiratory failure. Compared to conventional PSV, noisy PSV increased the variability of tidal volumes, and was associated with improved patient-ventilator synchrony, at comparable levels of gas exchange.

Trial registration

ClinicialTrials.gov, {"type":"clinical-trial","attrs":{"text":"NCT00786292","term_id":"NCT00786292"}}NCT00786292     

Adaptive support ventilation versus conventional ventilation for total ventilatory support in acute respiratory failure

Objective

To compare the short-term effects of adaptive support ventilation (ASV), an advanced closed-loop mode, with conventional volume or pressure-control ventilation in patients passively ventilated for acute respiratory failure.

Design

Prospective crossover interventional multicenter trial.

Setting

Six European academic intensive care units.

Patients

Eighty-eight patients in three groups: patients with no obvious lung disease (n = 22), restrictive lung disease (n = 36) or obstructive lung disease (n = 30).

Interventions

After measurements on conventional ventilation (CV) as set by the patients’ clinicians, each patient was switched to ASV set to obtain the same minute ventilation as during CV (isoMV condition). If this resulted in a change in PaCO₂, the minute ventilation setting of ASV was readjusted to achieve the same PaCO₂ as in CV (isoCO₂ condition).

Measurements and results

Compared with CV, PaCO₂ during ASV in isoMV condition and minute ventilation during ASV in isoCO₂ condition were slightly lower, with lower inspiratory work/minute performed by the ventilator (p < 0.01). Oxygenation and hemodynamics were unchanged. During ASV, respiratory rate was slightly lower and tidal volume (Vt) slightly greater (p < 0.01), especially in obstructed patients. During ASV there were different ventilatory patterns in the three groups, with lower Vt in patients with restrictive disease and prolonged expiratory time in obstructed patients, thus mimicking the clinicians’ choices for setting CV. In three chronic obstructive pulmonary disease patients the resulting Vt was unacceptably high.

Conclusions

Comparison between ASV and CV resulted either in similarities or in minor differences. Except for excessive Vt in a few obstructed patients, all differences were in favor of ASV.     

重型颅脑损伤并发急性肺损伤及急性呼吸窘迫综合征临床分析

目的探讨脑外伤后并发急性肺损伤(acute lung injury,ALI)及急性呼吸窘迫综合征(acute respiratory distresssyndrome,ARDS)的病理机制、诊断标准及治疗方法。方法对我院自2005年2月至2011年2月收治的重型颅脑损伤并发ALI患者27例和并发ARDS患者19例的临床资料进行回顾性分析。结果并发ALI的27例患者中,GOS评分I级9例,II级0例,III级1例,IV级7例,V级10例。并发ARDS的19例患者中,GOS评分I级10例,II级2例,III级4例,IV级2例,V级1例。结论 ALI及ARDS病死率高,严重影响脑外伤患者的生存率,临床上须给予足够的重视,积极预防、早期诊断、早期使用呼吸机及药物治疗,以提高患者的治愈率。     

Helmet CPAP vs. oxygen therapy in severe hypoxemic respiratory failure due to pneumonia

Purpose

The efficacy of noninvasive continuous positive airway pressure (CPAP) to improve outcomes in severe hypoxemic acute respiratory failure (hARF) due to pneumonia has not been clearly established. The aim of this study was to compare CPAP vs. oxygen therapy to reduce the risk of meeting criteria for endotracheal intubation (ETI).

Methods

In a multicenter randomized controlled trial conducted in four Italian centers patients with severe hARF due to pneumonia were randomized to receive helmet CPAP (CPAP group) or oxygen delivered with a Venturi mask (control group). The primary endpoint was the percentage of patients meeting criteria for ETI, including either one or more major criteria (respiratory arrest, respiratory pauses with unconsciousness, severe hemodynamic instability, intolerance) or at least two minor criteria (reduction of at least 30 % of basal PaO₂/FiO₂ ratio, increase of 20 % of PaCO₂, worsening of alertness, respiratory distress, SpO₂ less than 90 %, exhaustion).

Results

Between February 2010 and 2013, 40 patients were randomized to CPAP and 41 to Venturi mask. The proportion of patients meeting ETI criteria in the CPAP group was significantly lower compared to those in the control group (6/40 = 15 % vs. 26/41 = 63 %, respectively, p < 0.001; relative risk 0.24, 95 % CI 0.11–0.51; number needed to treat, 2) two patients were intubated in the CPAP group and one in the control group. The CPAP group showed a faster and greater improvement in oxygenation in comparison to controls (p < 0.001). In either study group, no relevant adverse events were detected.

Conclusions

Helmet CPAP reduces the risk of meeting ETI criteria compared to oxygen therapy in patients with severe hARF due to pneumonia.     

Effects of noninvasive positive pressure ventilatory support in non-COPD patients with acute respiratory insufficiency after early extubation

Objective: To investigate the effects of noninvasive positive pressure ventilation (NPPV) on pulmonary gas exchange, breathing pattern, intrapulmonary shunt fraction, oxygen consumption, and resting energy expenditure in patients with persistent acute respiratory failure but without chronic obstructive pulmonary disease (COPD) after early extubation. Design: Prospective study. Setting: Multidisciplinary intensive care unit of a university hospital. Patients: 15 patients after prolonged mechanical ventilation (> 72 h) with acute respiratory insufficiency after early extubation. Interventions: Criteria for early extubation were arterial oxygen tension (PaO₂) L 40 mm Hg (fractional inspired oxygen 0.21), arterial carbon dioxide tension (PaCO₂) K 55 mm Hg, pH > 7.32, respiratory rate K 40 breaths per min, tidal volume (V_T) L 3 ml/kg, rapid shallow breathing index K 190 and negative inspiratory force L 20 cmH₂O. After extubation, two modes of NPPV were applied [continuous positive airway pressure (CPAP) of 5 cmH₂O and pressure support ventilation (PSV) with 15 cmH₂O pressure support]. Measurements and main results: Oxygenation and ventilatory parameters improved during both modes of NPPV (p < 0.05): increase in PaO₂ of 11 mm Hg during CPAP and 21 mm Hg during PSV; decrease in intrapulmonary shunt fraction of 7 % during CPAP and 12 % during PSV; increase in tidal volume of 1 ml/kg during CPAP and 4 ml/kg during PSV; decrease in respiratory rate 6 breaths/min during CPAP and 9 breaths/min during PSV. Oxygen consumption (15 % during CPAP, 22 % during PSV) and resting energy expenditure (12 % during CPAP, 20 % during PSV) were reduced (p < 0.05). PaCO₂ decreased, whereas minute ventilation and pH increased during PSV (p < 0.05). The median duration of NPPV was 2 days. Two patients had to be reintubated. Conclusions: In non-COPD patients with persistent acute respiratory failure after early extubation, NPPV improved pulmonary gas exchange and breathing pattern, decreased intrapulmonary shunt fraction, and reduced the work of breathing. Received: 14 May 1999 Final revision received: 25 June 1999 Accepted: 6 July 1999     

Nocturnal nasal ventilatory support in the management of daytime hypercapnic respiratory failure

Nasal ventilation is becoming increasingly recognised as an effective therapeutic strategy to minimise or correct hypercapnia in patients with respiratory failure. Intervention may be required on a short or long term basis. In the majority of patients, respiratory failure develops initially during sleep. Assessing patients at risk of nocturnal hypoventilation, and instituting appropriate therapy, is becoming an increasingly important aspect of respiratory care. This review outlines methods and practices involved in commencing nasal ventilation therapy. Twenty-nine patients presenting with hypercapnic respiratory failure were managed with nocturnal nasal ventilation over a 12 month period. With the use of this therapy PaCO2 fell from 64(2) to 50(1)mmHg (Mean(SE)) (p<0.001), while PaO2 improved from 55(2) to 68(2)mmHg (p<0.001) during a mean ventilation time of 10(0.8) days. Those factors which must be addressed for a successful program outcome are discussed.