Clinical review: Liberation from mechanical ventilation

Mechanical ventilation is the defining event of intensive care unit (ICU) management. Although it is a life saving intervention in patients with acute respiratory failure and other disease entities, a major goal of critical care clinicians should be to liberate patients from mechanical ventilation as early as possible to avoid the multitude of complications and risks associated with prolonged unnecessary mechanical ventilation, including ventilator induced lung injury, ventilator associated pneumonia, increased length of ICU and hospital stay, and increased cost of care delivery. This review highlights the recent developments in assessing and testing for readiness of liberation from mechanical ventilation, the etiology of weaning failure, the value of weaning protocols, and a simple practical approach for liberation from mechanical ventilation.     

早期预警护理对ICU重症肺炎机械通气患者预后的影响

目的:探讨早期预警护理对重症监护室(intensive care unit,ICU)重症肺炎机械通气患者预后的影响。方法:选取北京市隆福医院ICU2017年1月至2018年5月收治的50例重症肺炎机械通气的患者为对照组,采用常规护理;选取同科室2018年6月至2019年11月收治的60例重症肺炎机械通气的患者为观察组,采用早期预警护理。比较两组患者的预后。结果:观察组护理后7 d的急性生理学与慢性健康状况评分表II(Acute Physiology and Chronic Health Evaluation II,APCHE II)评分、Murray肺损伤评分低于对照组,氧合指数高于对照组,机械通气时间、ICU住院时间短于对照组,撤机成功率高于对照组,差异有统计学意义(P<0.05或P<0.01)。观察组VAP、肺不张、下肢深静脉血栓等并发症总发生率低于对照组,差异有统计学意义(P=0.035)。结论:早期预警护理能进一步改善重症肺炎机械通气患者病理生理状况,减少并发症,缩短机械通气和入住ICU时间。     

Alveolar recruitment of atelectasis under combined high-frequency jet ventilation: a computed tomography study

OBJECTIVE: To quantify the effect of superimposed high-frequency jet ventilation on lung recruitment in adult patients with acute lung injury. DESIGN AND SETTING: Prospective clinical study in the intensive care unit of a university teaching hospital. PATIENTS: Eight adults suffering from acute lung injury with a mean lung injury score of 2.6+/-0.6 and pronounced atelectasis in at least two lung quadrants. The cause was either pneumonia ( n=5) or postoperative sepsis ( n=3). INTERVENTIONS: Superimposed high-frequency jet ventilation was initiated in patients following a mean of 4.4+/-1.7 days of conventional ventilation. Before and 4 h after the start of superimposed high-frequency jet ventilation differential lung volumes were determined by volumetry using computed tomography. MEASUREMENTS AND RESULTS: Superimposed high-frequency jet ventilation significantly increased the lung volume of every patient due to alveolar recruitment. This was achieved despite lower peak inspiratory pressures and higher PaO(2)/FIO(2) ratios than with conventional ventilation. CONCLUSIONS: Treatment with superimposed high-frequency jet ventilation for 4 h resulted in rapid alveolar recruitment in dependent lung areas, improved gas exchange, and better arterial oxygenation. It offers an effective and advantageous alternative to conventional ventilation for ventilatory management of respiratory insufficient patients.     

An integrated approach to prevent and treat respiratory failure in brain-injured patients

PURPOSE OF REVIEW: Brain-injured patients are at increased risk of extracerebral organ dysfunction, in particular ventilator-associated pneumonia. The purpose of this review is to discuss functional abnormalities, clinical treatment, and possible prevention of respiratory function abnormalities in brain-injured patients. RECENT FINDINGS: Ventilator-associated pneumonia worsens the neurologic outcome and increases the intensive care unit and hospital stay, costs, and risk of death. The respiratory dysfunction can be due to several causes, but atelectasis and/or consolidation of the lower lobes predominates in the most severe cases. Strategies should be implemented to prevent lung infections and accelerate weaning from mechanical ventilation to reduce the incidence of respiratory dysfunction and ventilator-associated pneumonia. SUMMARY: An integrated approach including appropriate ventilatory, antibiotic, and fluid management could be extremely useful, not only to prevent and more rapidly treat respiratory failure but also to improve neurologic outcome and reduce hospital stay. Further studies are warranted to better elucidate the pathophysiology and clinical treatment of respiratory dysfunction in brain-injured patients.     

Brain-lung crosstalk: Implications for neurocritical care patients

Major pulmonary disorders may occur after brain injuries as ventilator-associated pneumonia, acute respiratory distress syndrome or neurogenic pulmonary edema. They are key points for the management of brain-injured patients because respiratory failure and mechanical ventilation seem to be a risk factor for increased mortality, poor neurological outcome and longer intensive care unit or hospital length of stay. Brain and lung strongly interact via complex pathways from the brain to the lung but also from the lung to the brain. Several hypotheses have been proposed with a particular interest for the recently described "double hit" model. Ventilator setting in brain-injured patients with lung injuries has been poorly studied and intensivists are often fearful to use some parts of protective ventilation in patients with brain injury. This review aims to describe the epidemiology and pathophysiology of lung injuries in brain-injured patients, but also the impact of different modalities of mechanical ventilation on the brain in the context of acute brain injury.     

Noninvasive ventilation in acute respiratory failure

BACKGROUND: Noninvasive ventilation has assumed an important role in the management of respiratory failure in critical care units, but it must be used selectively depending on the patient's diagnosis and clinical characteristics. DATA: We review the strong evidence supporting the use of noninvasive ventilation for acute respiratory failure to prevent intubation in patients with chronic obstructive pulmonary disease exacerbations or acute cardiogenic pulmonary edema, and in immunocompromised patients, as well as to facilitate extubation in patients with chronic obstructive pulmonary disease who require initial intubation. Weaker evidence supports consideration of noninvasive ventilation for chronic obstructive pulmonary disease patients with postoperative or postextubation respiratory failure; patients with acute respiratory failure due to asthma exacerbations, pneumonia, acute lung injury, or acute respiratory distress syndrome; during bronchoscopy; or as a means of preoxygenation before intubation in critically ill patients with severe hypoxemia. CONCLUSION: Noninvasive ventilation has assumed an important role in managing patients with acute respiratory failure. Patients should be monitored closely for signs of noninvasive ventilation failure and promptly intubated before a crisis develops. The application of noninvasive ventilation by a trained and experienced intensive care unit team, with careful patient selection, should optimize patient outcomes.     

运动神经元病患者8年呼吸机治疗的气道护理

目的报告1例运动神经元病经呼吸机治疗8年的气道管理。方法采用个性化的吸痰方法,通过膨肺技术增加肺的顺应性、呼吸肌功能锻炼预防肺不张等。结果预防了呼吸机相关性肺炎发生。结论长期机械通气的患者,采用膨肺技术和有效的呼吸机治疗、护理措施,可预防肺不张和呼吸机相关性肺炎。     

重症肌无力病人胸腺手术围手术期的呼吸道管理

对40例重症肌无力病人切除胸腺组织或胸腺瘤治疗过程的围手术期呼吸道管理。术前进行必要的呼吸道准备，术中吸除气道分泌物，预防性应用抗生素。术后应动态观察血气指标，痰液性状及肌无力的各项指标，有效吸痰。使用呼吸机是肌无力危象和呼吸衰竭治疗的关键措施，须掌握时机，正确应用。     

Daily interruption of sedative infusions and complications of critical illness in mechanically ventilated patients

OBJECTIVE: In critically ill patients receiving mechanical ventilation, daily interruption of sedative infusions decreases duration of mechanical ventilation and intensive care unit length of stay. Whether this sedation strategy reduces the incidence of complications commonly associated with critical illness is not known. DESIGN: Blinded, retrospective chart review. SETTING: University-based hospital in Chicago, IL. PATIENTS: One hundred twenty-eight patients receiving mechanical ventilation and continuous infusions of sedative drugs in a medical intensive care unit. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We performed a blinded, retrospective evaluation of the database from our previous trial of 128 patients randomized to daily interruption of sedative infusions vs. sedation as directed by the medical intensive care unit team without this strategy. Seven distinct complications associated with mechanical ventilation and critical illness were identified: a) ventilator-associated pneumonia; b) upper gastrointestinal hemorrhage; c) bacteremia; d) barotrauma; e) venous thromboembolic disease; and f) cholestasis or g) sinusitis requiring surgical intervention. The incidence of complications was evaluated for each patient's hospital course.One hundred twenty-six of 128 charts were available for review. Patients undergoing daily interruption of sedative infusions experienced 13 complications (2.8%) vs. 26 (6.2%) in those subjected to conventional sedation techniques (p =.04). CONCLUSIONS: Daily interruption of sedative infusions in critically ill patients undergoing mechanical ventilation reduces intensive care unit length of stay and, in turn, decreases the incidence of complications of critical illness associated with prolonged intubation and mechanical ventilation.     

Respiratory support using multi-level lung ventilation in patients in critical state with systemic inflammatory response syndrome

PURPOSE: To prove the effectiveness of the method and improve lung gas exchange in patients with non-homogenous lung tissue damage with multi-level (3-level, MLV) ventilation. MATERIALS AND METHODS: Artificial lung ventilation (ALV) with MLV carried out in 13 patients with severe lung tissue damage (polytrauma, pneumonia and ARDS) treated at the unit of resuscitation and intensive care (for septic patients) SCH No 1 of Omsk since May 2011. The initial values of pO2 and oxygenation index were significantly reduced, the fraction of the intrapulmonary shunting - essentially increased. During the first day after the beginning of respiratory support with the use of MLV, was registered pO2, SaO2 and oxygenation index growth, there was a positive x-ray dynamics of improved lung tissue biomechanics. As a result of the ALV with MLV in 11 patients had achieved steady improvements of arterial oxygenation. The use of respiratory support with MLV in patients with severe lung damage leads to a significant improvement of the alveolar ventilation and arterial oxygenation, and to reduce the intrapulmonary shunting level. The use of this type of ventilation system versus traditional methods of respiratory therapy leads to respiratory failure solution, in reduce of duration of ALV terms and stay in the intensive care unit.     

Acute respiratory distress syndrome: diagnosis and management

Acute respiratory distress syndrome manifests as rapidly progressive dyspnea, tachypnea, and hypoxemia. Diagnostic criteria include acute onset, profound hypoxemia, bilateral pulmonary infiltrates, and the absence of left atrial hypertension. Acute respiratory distress syndrome is believed to occur when a pulmonary or extrapulmonary insult causes the release of inflammatory mediators, promoting neutrophil accumulation in the microcirculation of the lung. Neutrophils damage the vascular endothelium and alveolar epithelium, leading to pulmonary edema, hyaline membrane formation, decreased lung compliance, and difficult air exchange. Most cases of acute respiratory distress syndrome are associated with pneumonia or sepsis. It is estimated that 7.1 percent of all patients admitted to an intensive care unit and 16.1 percent of all patients on mechanical ventilation develop acute lung injury or acute respiratory distress syndrome. In-hospital mortality related to these conditions is between 34 and 55 percent, and most deaths are due to multiorgan failure. Acute respiratory distress syndrome often has to be differentiated from congestive heart failure, which usually has signs of fluid overload, and from pneumonia. Treatment of acute respiratory distress syndrome is supportive and includes mechanical ventilation, prophylaxis for stress ulcers and venous thromboembolism, nutritional support, and treatment of the underlying injury. Low tidal volume, high positive end-expiratory pressure, and conservative fluid therapy may improve outcomes. A spontaneous breathing trial is indicated as the patient improves and the underlying illness resolves. Patients who survive acute respiratory distress syndrome are at risk of diminished functional capacity, mental illness, and decreased quality of life; ongoing care by a primary care physician is beneficial for these patients.     

ICU cornerstone: high frequency ventilation is here to stay

With favourable and extensive experience in the neonatal intensive care unit (ICU) and the recent positive experience in the adult ICU, high-frequency ventilation has become a valuable alternative to conventional ventilation in acute lung injury. To arrive at this point, physicians' understanding of the characteristics and kinetics of acute lung injury had to become more distinct, and it was necessary to merge accumulated knowledge from experience with high-frequency ventilation in the neonatal population and that with conventional ventilation in adults. However, this now calls for a better designed clinical trial in the adult population that combines the three most important concepts for lung protection: early intervention (before acute respiratory distress syndrome is established); optimal lung recruitment; and careful avoidance of lung over-distention over the entire period of mechanical ventilation.     

集束化护理干预对ICU重型颅脑损伤机械通气患者呼吸机相关性肺炎的治疗效果

目的研究集束化护理干预对ICU重型颅脑损伤机械通气患者呼吸机相关性肺炎及治疗效果的影响。方法选取本院ICU病房收治的重型颅脑损伤患者120例,按照不同护理方式分成对照组与观察组各60例。对照组采用常规护理干预,观察组采用集束化护理干预。观察2组患者的治疗效果,比较呼吸相关性肺炎等并发症发生情况。结果观察组通气不良、VAP、胃肠胀气、损伤压迫等并发症发病率低于对照组(P0.05),患者机械通气时间及ICU监护时间少于对照组(P0.05);2组患者在干预前APACHE评分比较无差异(P0.05);干预后观察组APACHE评分低于对照组(P0.05)。结论对ICU重型颅脑损伤机械通气患者予以集束化护理干预治疗,能降低呼吸机相关性肺炎的发病率,提高患者的临床治疗疗效,临床上值得推广。     

The chest wall in acute lung injury/acute respiratory distress syndrome

PURPOSE OF REVIEW: There has recently been renewed interest in the chest wall during mechanical ventilation, related to lung-protective ventilation strategies, as well as in the role of abdominal pressure in many facets of critical illness. The purpose of this review is to address relevant issues related to the chest wall and mechanical ventilation, particularly in patients with acute lung injury/acute respiratory distress syndrome. RECENT FINDINGS: In mechanically ventilated patients with acute lung injury, intra-abdominal pressure is an important determinant of chest wall compliance. With elevated intra-abdominal pressure, the compliance of the chest wall and total respiratory system is decreased, with a relatively normal compliance of the lungs. The lung compression effects of increased intra-abdominal pressure may lead to a loss of lung volume with atelectasis. An appropriate level of positive end-expiratory pressure is necessary to counterbalance this collapsing effect on the lungs. Also, the stiff chest wall results in a lower transpulmonary pressure during positive-pressure ventilation. SUMMARY: As chest wall compliance may have important clinical implications during positive-pressure ventilation, the physiology of this effect should be considered, particularly in patients with acute lung injury and increased abdominal pressure.     

Outcome of morbid obesity in the intensive care unit

This was a retrospective chart review of consecutive obese patients admitted to the medical intensive care unit. Patients were divided into 2 groups: mild to moderately obese (group 1, body mass index =30-40 kg/m(2)) and morbidly obese (group 2, body mass index >40 kg/m(2)). Acute Physiology and Chronic Health Evaluation II scores were not significantly different between the 2 groups. Morbidly obese patients (group 2) had higher rates of mortality and nursing home admission. They also showed higher rates of intensive care unit complications including sepsis, nosocomial pneumonia, acute respiratory distress syndrome, catheter infection, tracheostomy, and acute renal failure. Their median length of mechanical ventilation was longer (2 days, range 2-12 vs 9 days, range 1-37,P = .009). In a logistic regression analysis, morbid obesity remained a significant predictor of death or disposition to nursing home even after controlling for age (P = .019, odds ratio = 7.60, 95% confidence interval = 1.39-41.6). Morbidly obese patients (body mass index >40 kg/m(2)) admitted to intensive care units have higher rates of mortality, nursing home admission, and intensive care unit complications and have longer stays in the intensive care unit and time on mechanical ventilation.     

Outcome of bone marrow transplantation patients requiring mechanical ventilation

OBJECTIVE: To identify outcome predictors in bone marrow transplantation (BMT) patients admitted to the intensive care unit (ICU) of The University of Texas M. D. Anderson Cancer Center who required endotracheal intubation and mechanical ventilation. DESIGN: Retrospective, comparative study. SETTING: A 16-bed medical intensive care unit in a university teaching cancer center. PATIENTS: The records of 60 consecutive BMT patients who developed respiratory failure requiring mechanical ventilation were reviewed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The most frequent complication leading to respiratory failure was pneumonia (41%) followed by diffuse alveolar hemorrhage (37%). Eighteen percent of the patients were extubated and discharged from the ICU, but only 5% were alive at 6 months. Graft vs. host disease was a predictor of a poor outcome (p < .05). Breast cancer as an underlying disease and pulmonary edema as a complication were favorable predictive factors (p < .05). Five of 26 patients with diffuse alveolar hemorrhage and four of 33 patients with pneumonia survived. We found no relationship between survival and age, gender, BMT type, or Acute Physiology and Chronic Health Evaluation II score. Prolonged mechanical ventilation (> or =15 days) and late development of respiratory failure (>30 days after BMT) were associated with poor prognosis. CONCLUSIONS: The ICU survival rate of BMT patients who developed pulmonary complications and required mechanical ventilation was 18%. Prognostic factors were described identifying patients with a substantial survival rate as well as those in whom mechanical ventilation was futile.     

Six-month survival of patients with acute lung injury: prospective cohort study

OBJECTIVE: Both short- and long-term outcome studies in acute lung injury (ALI) performed thus far were conducted before the implementation of recent advances in mechanical ventilation and supportive care and/or in the context of clinical trials with restricted inclusion criteria. We sought to determine the outcome of consecutive acute lung injury patients after the implementation of these interventions. DESIGN: Prospective cohort study. SETTING: Three intensive care units of two tertiary care hospitals. PATIENTS: Patients with acute lung injury treated from October 2005 to May 2006, excluding those with no research authorization or do-not-resuscitate order. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The investigators collected detailed information about comorbidities, severity of pulmonary and nonpulmonary organ failures, complications, respiratory support, and other interventions. The main outcome measure was mortality 6 months after the onset of acute lung injury. From 142 patients enrolled over a 6-month period, 24 (17%) died in the intensive care unit, 38 (27%) in the hospital, and 55 (39%) by the end of the 6-month follow-up. Median (interquartile range) intensive care unit length of stay, duration of mechanical ventilation, and number of day 28 ventilator-free days were 7.1 (3.6-11.3), 5.7 (2.6-10.3), and, 19.0 (0-24.2) days. Multiple logistic regression analysis identified underlying Charlson comorbidity score (odds ratio 3.11, 95% confidence interval 2.01-5.05) for each point increase, transfer admission from the floor or outside hospital (odds ratio 3.75, 95% confidence interval 1.41-10.99), day 3 cardiovascular failure (odds ratio 3.30, 95% confidence interval 1.19-9.92), and day 3 Pao2/Fio2 (odds ratio 0.94, 95% confidence interval 0.88-0.99) as significant predictors of 6-month mortality. CONCLUSIONS: With the implementation of recent advances in mechanical ventilation and supportive care, premorbid condition is the most important determinant of acute lung injury survival.     

Pulmonary problems

Prevention of pulmonary complications continues to be a major goal of therapy in the care of patients in the postoperative period. Numerous factors, including anesthesia and surgery-induced diaphragmatic dysfunction, reductions in lung volumes and capacities, and release of mediators that damage the endothelium, set the stage for the development of complications such as atelectasis, pneumonia, and ARDS. Nursing assessment focuses on the early identification and evaluation of respiratory distress and degree of oxygen supply/demand imbalance. Intervention focuses on restoration of appropriate ventilation/perfusion matching and provision of adequate oxygen to meet tissue metabolic demands.     

俯卧位通气在呼吸衰竭患者应用中的护理体会

目的:探讨呼吸衰竭患者应用俯卧位通气的护理效果。方法:回顾性分析我科23例呼吸衰竭患者应用俯卧位通气及其相关护理措施。结果:经俯卧位通气治疗后,21例患者症状明显改善,顺利转出ICU。结论:俯卧位通气能改善患者的症状,加之强有力的护理措施,促进肺部分泌物的排出,减少肺不张等并发症的发生,促进康复。     

危重症甲型H1N1流行性感冒病毒肺炎的临床特征——附17例报告

目的:探讨危重症甲型H1N1流行性感冒病毒(甲流)肺炎患者的主要临床特点,分析各临床检验指标与病情严重程度的关系。方法:收集入住呼吸重症监护病房(RICU)的17例危重症甲流肺炎患者的临床资料,归纳分析其临床特征。结果:17例患者以发热、咽痛、咳嗽、肌肉酸痛为主要症状。双肺多发实变影12例(71%)。入院后白细胞为(3.4～25.1)×109/L,中性粒细胞(2.72～21.84)×109/L,中性粒细胞比例58.6%～96.4%,淋巴细胞5.1%～21.6%。CRP 34.6～381.9 mg/L,乳酸脱氢酶(LDH)310～820 U/L,白蛋白<30 g/L10例(59%),ALT升高6例(35%),血清肌酐升高5例(29%),脑钠肽升高4例(24%)。氧合指数<300 mm Hg 13例(76%)。均予奥司他韦治疗,气管插管机械通气支持治疗3例(18%)。死亡2例(12%),均为男性,均为气管插管机械通气者。结论:LDH、CRP升高、炎性细胞增多提示危重症甲流肺炎患者肺部损害加重;机械通气支持治疗对于部分肺内广泛实变者效果不理想,且相关的并发症是部分患者病情加重或死亡的促发因素。