Approach to patients with long-term weaning failure

Efforts to treat reversible disease processes that contribute to ventilator dependency in the intensive care unit (ICU) fail in up to 20% of patients, resulting in prolonged mechanical ventilation (PMV). Resolution of the insults that necessitated ICU admission and mechanical ventilation may be incomplete, and the economic pressure to transfer patients is ever increasing. The choice of post-ICU disposition depends on the patient's clinical condition, the resources of the transfer destination, and whether weaning attempts will continue. This article reviews data from a decade of weaning beyond the ICU, including outcomes of more than 2700 patients with PMV afforded continued attempts at liberation in long-term acute care facilities and other post-ICU weaning venues. Assessment and treatment, weaning strategies, and complications of patients with PMV are described.     

Weaning critically ill patients from mechanical ventilation: a protocol from a multicenter retrospective cohort study

BackgroundMechanical ventilation (MV) is an important lifesaving method in intensive care unit (ICU). Prolonged MV is associated with ventilator associated pneumonia (VAP) and other complications. However, premature weaning from MV may lead to higher risk of reintubation or mortality. Therefore, timely and safe weaning from MV is important. In addition, identification of the right patient and performing a suitable weaning process is necessary. Although several guidelines about weaning have been reported, compliance with these guidelines is unknown. Therefore, the aim of this study is to explore the variation of weaning in China, associations between initial MV reason and clinical outcomes, and factors associated with weaning strategies using a multicenter cohort.MethodsThis multicenter retrospective cohort study will be conducted at 17 adult ICUs in China, that included patients who were admitted in this 17 ICUs between October 2020 and February 2021. Patients under 18 years of age and patients without the possibility for weaning will be excluded. The questionnaire information will be registered by a specific clinician in each center who has been evaluated and qualified to carry out the study.DiscussionIn a previous observational study of weaning in 17 ICUs in China, weaning practices varies nationally. Therefore, a multicenter retrospective cohort study is necessary to be conducted to explore the present weaning methods used in China.Trial RegistrationChinese Clinical Trial Registry (ChiCTR) (No. ChiCTR2100044634).     

Outcomes in post-ICU mechanical ventilation: a therapist-implemented weaning protocol

BACKGROUND: Therapist-implemented protocols have been used to extubate or wean patients in the ICU setting. Barlow Respiratory Hospital (BRH) functions as a center for weaning patients from prolonged mechanical ventilation (PMV) in the post-ICU setting of a long-term acute-care (LTAC) facility. A therapist-implemented patient-specific (TIPS) weaning protocol was developed at BRH to standardize weaning from PMV. STUDY DESIGN: Prospective cohort study with historical control. METHODS: A weaning protocol incorporating the procedures and pace of LTAC weaning was developed using available scientific evidence and expert consensus. After training of staff, collection and analysis of pilot data, and revisions and refinement of the protocol, the TIPS protocol was implemented hospital-wide. It was monitored for outcome, variance, and respiratory care practitioner (RCP) and physician compliance. RESULTS: Forty-six RCPs worked with eight pulmonologists treating 271 consecutive patients admitted for weaning from PMV during an 18-month period. Nineteen patients were excluded from weaning attempts by any method after initial physician evaluation. The remaining 252 patients (9,135 total ventilator days) were compared with a group of 238 patients treated by the same physicians in the 2 years before instituting protocol weaning. Median time to wean declined significantly from 29 days in historical control subjects to 17 days for TIPS protocol patients (p < 0.001). Outcomes (scored at discharge) were comparable for the two groups (TIPS group vs control group): weaned, 54.7% vs 58.4%; ventilator-dependent, 17.9% vs 10.9%; died, 27.4% vs 30.7% (p = 0.10). Variances incurred by physicians and RCPs were 324 and 136, respectively, for the 9,135 ventilator days. CONCLUSIONS: Patients weaned from PMV using a new therapist-implemented protocol at BRH, an LTAC facility specializing in weaning, had significantly shorter time to weaning than historical control subjects, with comparable outcomes. The weaning outcome data collected after the implementation of the TIPS protocol are in fact attributable to its use, as we found a high degree of compliance with the protocol.     

Mechanical ventilation in chronic obstructive lung disease

Exacerbations of COPD are a leading indication for MV in the intensive care unit. A thorough understanding of the pathophysiology of AVF in COPD is critical for physicians caring for these patients. In particular, physicians should understand DHI and use the ventilator and ancillary techniques to minimize its impact. Noninvasive positive-pressure ventilation should be considered strongly in relatively stable patients with an adequate mental status and manageable secretions. Once AVF resolves, patients should be removed from the ventilator as soon as is safe to do so to minimize the adverse effects of prolonged MV. An organized approach to weaning and identifying patients capable of independent breathing is crucial. Most patients with COPD and AVF benefit from MV and generally return to or approach their premorbid functional status. A significant subset, however, will not benefit from, or choose not to undergo, MV. Deciding upon appropriate therapeutic options for these patients relies heavily on effective communication between physician and patient. Comprehensive discussions before the development of AVF can assist decision-making after respiratory failure develops.     

Automated weaning from mechanical ventilation

Mechanical ventilation (MV) is one of the lifesaving techniques applied to critically ill patients at bedside. However, some complications, such as ventilator-induced lung injury and ventilator-associated pneumonia, may occur in a patient undertaking MV and are often related to the duration of MV. Some written protocols have been proposed to reduce the risk of such complications, but they can be time consuming, leading to fluctuation in protocol implementation and compliance. Moreover, written instructions tend to be general and thus cannot cover all possible scenarios, resulting in variable interpretation of the protocol. To overcome these limiting factors, protocols have been computerized and there is convincing evidence in the literature showing that computerized protocols benefit management of the process and reduce the time a patient spends under MV. QuickWean is a computer-aided weaning protocol implemented on the Hamilton S1 ventilator (Hamilton Medical AG, Bonaduz, Switzerland), which guides the patient through the weaning process without requiring any intervention by the treating physician. The fully-automated ventilation mode is INTELLiVENT^®-ASV (Hamilton Medical AG), which is set according to the patient’s respiratory mechanics, patient-ventilator interaction, peripheral oxygen saturation (SpO₂) and pulmonary end-tidal carbon dioxide (PetCO₂). The INTELLiVENT^®-ASV mode sets automatically each minute to provide accurate ventilation, pressure support, fraction of inspired oxygen and positive end-expiratory pressure based on the patient’s needs. QuickWean can be pre-set to match the established weaning policy of an intensive care unit as well as being customized to a patient’s needs. It provides a progressive reduction of respiratory support, and guides the patient through the spontaneous breathing trial (SBT). At the end of the SBT, the ventilator re-starts the previous ventilation support and provides a report of the successful SBT. During all phases, PetCO₂, SpO₂ and all breathing parameters are monitored. This new automated weaning tool may improve the safety and effectiveness of an SBT, reducing the time spent in the process of weaning and providing a lower workload for the treating physician.     

Ventilator management protocols in pediatrics

Management of mechanical ventilation is a complex process with outcomes affected by multiple patient and caregiver variable. Well-constructed protocols represent the synthesis of best available evidence regarding ventilator management. In adults, protocols improve important outcomes such as duration of mechanical ventilation, length of stay, and complication rates; however, protocols are not uniformly successful. In pediatrics, the available evidence does not suggest that ventilator management protocols should be adopted routinely, which may be due to pediatric-specific attributes such as a generally shorter weaning duration. Evidence suggests support for protocols to carefully titrate sedation. In addition, daily assessment of SBTs improves patient outcomes and should be more uniformly adopted in pediatrics. Ventilator-related outcomes may be affected by other confounding factors such as nutrition and fluid balance. Specific subpopulations, such as children who have congenital heart disease, may present opportunities for focused use of ventilator management protocols. Protocolized ventilation has an important place in trials of new therapeutic strategies such as surfactant or proning. It is hoped that future research will further define the appropriate use of protocols in the general PICU population. Although specific protocols cannot be routinely recommended, a multidisciplinary team approach to synthesizing available literature and determining best practice is a useful model. This approach will foster "team ownership" of ventilator management by all involved, thus engendering the best possible outcomes for critically ill children who require mechanical ventilation.     

Shock on admission day is the best predictor of prolonged mechanical ventilation in the ICU

STUDY OBJECTIVES: To determine the incidence of prolonged mechanical ventilation (PMV), which is associated with increased health-care costs and risks of adverse events, and to identify its early predictors. DESIGN: Retrospective cohort. SETTING: A medical-surgical ICU in a university-affiliated hospital.Patients or participants: All patients admitted to the ICU over 3 years who received mechanical ventilation (MV) for > 12 h. INTERVENTIONS: None. MEASUREMENTS: PMV was defined as MV lasting > 21 days. We recorded epidemiologic data, severity scores, worst Pao(2)/fraction of inspired oxygen (Fio(2)), presence of shock on ICU admission day, cause for MV, length of MV, ICU length of stay (LOS), and hospital LOS. PMV patients were compared to patients weaned before 21 days (non-PMV group) to determine predictors of PMV. RESULTS: Of 551 hospital admissions, 319 patients (58%) required MV > 12 h. One hundred thirty patients died early and were excluded. Seventy-nine patients (14%) required PMV. The non-PMV group consisted of 110 patients. Simplified acute physiology score (SAPS) II, APACHE (acute physiology and chronic health evaluation) II, therapeutic intervention scoring system, Pao(2)/Fio(2), shock, ICU LOS, and hospital LOS differed significantly between groups. However, logistic regression identified shock on ICU admission day as the only independent predictor of PMV (odds ratio, 3.10; p = 0.001). SAPS II and Pao(2)/Fio(2) had the nearest coefficients and were used to build the predictive model. Sensitivity analysis was performed including the 130 patients who died early, and shock remained the most powerful predictor. CONCLUSIONS: PMV was a frequent event in this cohort. The presence of shock on ICU admission day was the only prognostic factor, even adjusting for severity of illness and hypoxemia.     

营养支持对45例早期机械通气患者的治疗作用观察

目的 探讨营养支持对接受机械通气患者的早期治疗作用.方法 将接受机械通气治疗的45例危重病患者随机分为全肠外营养(PN)组、全营养食物均浆肠内营养(EN)组和肠内肠外营养相结合(PN EN)组,各组患者均接受等氮等热量营养支持.结果 各组脱机时间比较无显著性差异,营养效果相似,肠外组和混合组较快达氮平衡.肠外组和混合组的胃肠道并发症较肠内组少,两者比较有显著性差异.肠内组费用最便宜,混合组免疫学指标最高.结论 机械通气患者普遍存在营养不良,可采用肠内营养或肠外营养或二者结合方式进行营养,肠内营养经济方便,有利于肠道能力恢复,而全肠外营养效果准确迅速,两者结合能互相取长补短.     

Long-term acute care: a review of the literature

Long-term acute care (LTAC) represents a rapidly growing category of Medicare providers, but little is known about its quality, outcomes, and cost-effectiveness. Its defining characteristic, as set by Medicare, is an average length of stay of greater than 25 days. Modern LTAC emerged in the early 1980s as a setting for the weaning of ventilator-dependent patients. The industry has developed greatly in the last few years, with for-profit corporations dominating the field, and as Medicare expenditures have grown, new payment systems have emerged to limit spiraling costs. Although LTAC is mainly known for providing chronic ventilator weaning, the case mix is varied. The majority of outcome studies in this setting have been done on pulmonary patients, with fewer data available on nonventilator patients. This article analyzes studies of LTAC that are currently available, discusses some of the public policy issues surrounding this level of care, and suggests a research agenda, including a role for the field of geriatrics.     

Four-year experience with a unit for long-term ventilation (respiratory special care unit) at the Cleveland Clinic Foundation.

BACKGROUND: In the context that special weaning units have been advocated as effective alternatives to the ICU for weaning selected patients, we initiated a Respiratory Special Care Unit (ReSCU) at the Cleveland Clinic Hospital in August 1993. The goals of the ReSCU were the following: (1) to wean ventilator-dependent patients when possible; and (2) when weaning was not possible, to optimize patient and family instruction for patients going home with ventilatory support. This study presents our 4-year experience with 212 patients managed in the ReSCU and analyzes clinical features associated with favorable clinical outcomes. METHODS: The features of the ReSCU include six private beds in a pulmonary inpatient ward staffed by nurses with special pulmonary expertise; 24-h respiratory therapy supervision; bedside and central noninvasive monitoring (i.e., continuous pulse oximetry, end tidal capnometry, and ventilator alarms); and a multidisciplinary approach involving dietitians, physical therapists, occupational therapists, social workers, and speech pathologists. All ReSCU patients were cared for primarily by a pulmonary/critical care attending physician and fellow, with consultative input solicited as deemed necessary. The criteria for admission to the ReSCU included hemodynamic stability; absence of an arrhythmia requiring telemetry; and in the attending physician's judgment, the ability to benefit from the ReSCU. RESULTS: Between August 23, 1993, and August 31, 1997, 212 patients were admitted to the ReSCU. The median age was 68 years old; 55% were women; 86% were white; and 55% were transferred from the medical ICU. Underlying reasons for ventilator dependence were ARDS from a nonsurgical cause (33%), ARDS following surgery (18%), status post-cardiothoracic surgery (13%), status post-thoracic surgery (12%), and COPD (12%). The median length of ReSCU stay was 17 days (interquartile range, 10 to 29 days). Eighteen percent (n = 38) died during the hospitalization. Among the 174 survivors, complete ventilator independence was achieved in 127 patients (60% of the 212 patient cohort), 28 patients were ventilator dependent (13% of 212 patients), and the remaining 19 patients (9%) required partial ventilatory support. Univariate analysis regarding the association of baseline characteristics with death identified lower albumin and transferrin levels, increasing age, and the physician's estimate of lower weaning likelihood as significant correlates of death. In contrast, achieving complete ventilator independence was associated with a higher serum albumin level, a nonmedical ICU referral source, a cause of respiratory failure other than COPD, and a physician's estimate of higher weaning likelihood. To analyze the financial impact of the ReSCU, we assumed that ReSCU patients would have otherwise stayed in the medical ICU and compared the charges (ICU vs ReSCU) with, for a subset of patients, the true costs of ReSCU vs. ICU care. Analyses of both charges and cost differences showed similar savings associated with ReSCU care ($13,339 per patient [charges] and $10,694 per patient [costs]). CONCLUSIONS: We conclude the following: (1) the rate of achieving complete ventilator independence in the ReSCU was high; and (2) based on our achieving clinical outcomes, which are comparable to the most favorable rates reported in other series from ventilator units, we conclude that the ReSCU can be an effective and cost-saving alternative to the ICU for carefully selected patients.     

三种不同脱机方式在慢性阻塞性肺疾病急性加重期中的应用研究

目的：比较程序化脱机法、智能化脱机法和经验性脱机法三种脱机方式在慢性阻塞性肺疾病急性加重期（ AECOPD）患者脱机过程中的优劣。方法选取96例行有创机械通气的AECOPD患者,进行随机对照试验。结果程序组和智能组有创机械通气（ MV）时间、ICU住院时间均明显短于经验组,差异有统计学意义（P均＜0.01）。三组呼吸机相关肺炎（VAP）的发生率分别为18.8％、25.0％、46.9％,差异有统计学意义（ P＜0.05）。但三组住院病死率、脱机成功率和48 h再插管率差异无统计学意义（ P均＞0.05）。结论程序化脱机法和智能化脱机法与经验性脱机法比较,均可减少MV时间和ICU住院时间,并明显降低VAP的发生率。     

A computer-controlled ventilator weaning system

Weaning of patients from mechanical ventilation is a time-consuming, labor-intensive process. Because most weaning decisions are based on objective data, we tested a computer-directed weaning system on postoperative patients. We developed an automatic, computer-controlled ventilator weaning system which interfaces a laptop computer to a ventilator and a pulse oximeter. The laptop computer program accesses patient data through the ventilator and pulse oximeter to make weaning decisions. The computer directly controls the ventilator through an interface developed for this system. We tested the system in nine postoperative patients who met the following criteria: negative inspiratory force less than or equal to -20 cm H2O, vital capacity greater than 10 ml/kg, inspired oxygen concentration less than or equal to 40 percent, and satisfactory arterial blood gas parameters (pH between 7.32 and 7.48, PCO2 between 32 and 48, and oxygen saturation greater than or equal to 90 percent). The computer decreased the SIMV rate by 2 breaths/min every 5 min until a rate of 2 breaths/min was reached, then decreased pressure support by 4 cm H2O every 5 min as long as the patient met the following criteria: respiratory rate between 8 and 25 breaths/min, minute ventilation between 6 and 14 L, and pulse oximeter oxygen saturation greater than or equal to 90 percent. If unsatisfactory weaning criteria were noted, the system automatically returned the patient to the previous weaning level. We successfully weaned nine patients using the system. Additional studies are underway to determine if this system can be used in medical patients. We believe this computer-controlled ventilator weaning system can be used successfully in patients requiring mechanical ventilation and may decrease the time and cost associated with the care of these patients.     

Ventilators and weaning modes

Although new ventilator modes have become available to facilitate weaning, there is little evidence that these have improved weaning outcomes. Knowledge based computer weaning systems have also been described, but these are in their infancy, and their role is unclear. Prospective, randomized clinical studies are required to examine whether such modalities are superior to existing approaches.     

The control of breathing during weaning from mechanical ventilation

Using the recruitment threshold technique, we measured the CO2 responsiveness of the unloaded respiratory pump in 14 mechanically ventilated patients prior to weaning. The CO2 recruitment threshold (CO2RT) was compared with the arterial CO2 tension during unassisted breathing (CO2SB) and with the PaCO2 during mechanical ventilation (CO2MV) at machine settings determined by the primary physician. Based on these comparisons, we tested the hypotheses that (1) patients without weaning-induced respiratory distress (group 1) maintain CO2SB near CO2RT, (2) patients with weaning-induced respiratory distress (group 2) retain CO2SB above CO2RT, thereby manifesting incomplete load compensation, and (3) CO2MV is ventilator setting dependent and provides insufficient information about the ventilatory requirement during weaning. Respiratory distress was prospectively defined as sustained tachypnea (rate greater than or equal to 30) or intense dyspnea (Borg scale rating) and limited weaning in nine of 14 patients. The average CO2RT was 40 mm Hg in both groups. All patients in group 1 maintained CO2SB near CO2RT (p greater than 0.1). Seven of nine patients in group 2 retained CO2 by greater than or equal to 3 mm Hg above CO2RT (p less than 0.01). There was no significant difference between CO2MV and CO2SB in either group. We conclude that CO2RT provides a better reference of the adequacy of ventilatory load compensation during weather than CO2MV.     

Relation of patient age to outcome of percutaneous mitral valvuloplasty

The aim of this study was to evaluate the impact of age on immediate- and long-term outcomes of percutaneous mitral balloon valvuloplasty (PMV). PMV is the first-line treatment for patients with symptomatic mitral stenosis. However, long-term results in large series of patients from Europe and the United States have been found less favorable than those from Asia and South America involving younger patients. Six hundred ten patients who underwent 626 PMV procedures were prospectively followed for 6.1 +/- 4.10 years using clinical and echocardiographic evaluation. Patients were divided in quartiles according to age: < or =41 years (n = 163), 42 to 53 years (n = 163), 54 to 63 years (n = 142), and >63 years (n = 158). The success of PMV was defined as valve area > or =1.5 cm(2) without severe regurgitation; restenosis was defined as a loss > or =50% of initial gain, with a valve area of <1.5 cm(2). PMV success was significantly more prevalent in younger patients: 95.7% in group 1, 91.4% in group 2, 86.4% in group 3, and 83.4% in group 4 (p = 0.002). No significant differences in complications were found among all age groups, including death, cardiac tamponade, emergency mitral replacement, and any embolic events (p = NS). Event-free survival was greater in younger patients (p <0.0001), but on multivariate analysis, age was not an independent predictor of events (p = NS). Restenosis occurred in 27.9% of patients, throughout all groups (p = NS). In conclusion, PMV may be safely and effectively performed in younger and older patients. Although event-free survival was greater in younger groups, multivariate analysis did not find that age was an independent predictor of events.     

Transplant center characteristics and clinical outcomes after hematopoietic stem cell transplantation: what do we know?

Center effects are differences in outcome among treatment centers that cannot be explained by identifiable differences in patients treated or specific treatments applied and are presumed to result from differences in the ways health care is delivered. This paper will briefly review studies of association between treatment center factors and clinical outcomes in general medicine and surgery and look more closely at studies involving hematopoietic stem cell transplantation. We will also attempt to identify conceptual domains to study further the processes and mechanisms that may be associated with better outcomes.     

Determinants of prolonged mechanical ventilation in patients with chronic obstructive pulmonary diseases and acute hypercapnic respiratory failure

BACKGROUND: The aim of the present study was to identify early risk factors for prolonged mechanical ventilation (PMV) in chronic obstructive pulmonary disease (COPD) patients admitted to respiratory intensive care units (RICU) for acute hypercapnic respiratory failure. METHODS: PMV was defined as invasive ventilation lasting longer than 7 days. Between January 1, 2000 and December 31, 2005, epidemiological and clinical data on RICU admission day were retrospectively analyzed for eligible patients. Univariate and multiple stepwise logistic regression analyses were used for statistical analysis. RESULTS: A total of 152 patients were eligible for evaluation during the 6-year study period and their mean age was 63+/-12 years. Fifty-one patients died before day 7 after the onset of MV (early death group). Of the remaining 101 patients who survived until day 7, 56 had been weaned successfully (non-PMV group) and 45 continued to receive MV (PMV group). Logistic regression analysis showed that age above 65 (OR=1.98, 95% CI=0.96-4.17, P=0.011), a pH of 7.30 or less measured 12 h after ventilation (OR=2.09, 95% CI=1.17-5.64, P=0.002), an APACHE II score above 20 (OR=3.25, 95% CI=1.58-7.10, P<0.001), development of non-respiratory organ failure (OR=4.67, 95% CI=1.54-9.71, P<0.001), and the presence of shock (OR=4.71, 95% CI=2.14-10.09, P<0.001) were independently associated with PMV. The presence of two factors predicted PMV with a sensitivity of 86% and a specificity of 94%. CONCLUSION: Age, APACHE II score, refractory acidosis, presence of non-respiratory organ failure, and shock on RICU admission day were early determinants of PMV in patients with COPD and acute hypercapnic respiratory failure.