Specialized Weaning Units Research Articles

Diaphragm ultrasound in patients with prolonged weaning from mechanical ventilation.

Several publications have examined diaphragmatic ultrasound using two-dimensional (2D) parameters in the context of weaning from mechanical ventilation (MV) and extubation. However, the studied cohorts had rather short duration of ventilation. Examinations on patients with prolonged weaning after long-term ventilation were missing. It was the aim of this study to assess of the diaphragm and peripheral musculature of patients undergoing prolonged weaning creating a chronological sequence of ultrasonic parameters during the course of weaning. This study was carried out as a monocentric, prospective observational cross-sectional study. Patients in prolonged weaning who were transferred to a specialized weaning unit were eligible for inclusion if they were ventilated invasively by means of an endotracheal tube or tracheal cannula and if their expected treatment period was at least 5 days. Diaphragmatic function and one representative peripheral muscle were examined in 50 patients between March 2020 and April 2021. The 2D sonographic parameters of diaphragm and diaphragmatic function consisted of diaphragmatic thickness (Tdi) at the end of inspiration and expiration, the fractional thickening (FT) and the diaphragmatic excursion. Additionally, the M. quadriceps femoris was sonographically assessed at two locations. The difference of measurements between the first and the last measuring timepoint were examined using the Wilcoxon signed-rank test. For a longer chronological sequence, the Friedman's rank sum test with subsequent Wilcoxon-Nemenyi-McDonald-Thompson test for multiple comparisons was carried out. Fifty patients with prolonged weaning were included. The median duration of MV before transfer to the weaning unit was 11.5 [interquartile range (IQR) 10] days. Forty-one patients could be assessed over the full course of weaning, with 38 successfully weaned. Within these 41 patients, the sonographic parameters of the diaphragm slightly increased over the course of weaning indicating an increase in thickness and mobility. Especially parameters which represented an active movement reached statistical significance, i.e., inspiratory Tdi when assessed under spontaneous breathing [begin 3.41 (0.99) vs. end 3.43 (1.31) mm; P=0.01] and diaphragmatic excursion [begin 0.7 (0.8) vs. end 0.9 (0.6) cm; P=0.01]. The presence of positive end-expiratory pressure (PEEP) and pressure support did not influence the sonographic parameters significantly. The M. quadriceps femoris, in contrast, decreased slightly but constantly over the time [lower third: begin 1.36 (0.48) vs. end 1.28 (0.36) cm; P=0.054]. The present study is the first one to longitudinally analyse diaphragmatic ultrasound in patients with prolonged weaning. Sonographic assessment showed that Tdi and excursion increased over the course of prolonged weaning, while the diameter of a representative peripheral muscle decreased. However, the changes are rather small, and data show a wide dispersion. To allow a potential, standardized use of diaphragm ultrasound for diagnostic decision support in prolonged weaning, further studies in this specific patient group are required.

Development of a machine learning model for prediction of the duration of unassisted spontaneous breathing in patients during prolonged weaning from mechanical ventilation

PurposeTreatment of patients undergoing prolonged weaning from mechanical ventilation includes repeated spontaneous breathing trials (SBTs) without respiratory support, whose duration must be balanced critically to prevent over- and underload of respiratory musculature. This study aimed to develop a machine learning model to predict the duration of unassisted spontaneous breathing. Materials and methodsStructured clinical data of patients from a specialized weaning unit were used to develop (1) a classifier model to qualitatively predict an increase of duration, (2) a regressor model to quantitatively predict the precise duration of SBTs on the next day, and (3) the duration difference between the current and following day. 61 features, known to influence weaning, were included into a Histogram-based gradient boosting model. The models were trained and evaluated using separated data sets. Results18.948 patient-days from 1018 individual patients were included. The classifier model yielded an ROC-AUC of 0.713. The regressor models displayed a mean absolute error of 2:50 h for prediction of absolute durations and 2:47 h for day-to-day difference. ConclusionsThe developed machine learning model showed informed results when predicting the spontaneous breathing capacity of a patient in prolonged weaning, however lacking prognostic quality required for direct translation to clinical use.

Specialized Weaning Unit in the Trajectory of SARS-CoV-2 ARDS: Influence of Limb Muscle Strength on Decannulation and Rehabilitation.

Patients with ARDS due to COVID-19 may require tracheostomy and transfer to a weaning center. To date, data on the outcome of these patients are scarce. The objectives of this study were to determine the factors associated with time to decannulation and limb-muscle strength recovery. This was an observational retrospective study of subjects with COVID-19-related ARDS requiring tracheostomy after prolonged ventilation, who were subsequently transferred to a weaning center from April 4, 2020-May 30, 2020. Forty-three subjects were included. Median age (interquartile range) was 61 (48-66) y; 81% were men, and median body mass index (BMI) was 30 (26-35) kg/m2. Tracheostomy was performed after a median of 19 (12-27) d of mechanical ventilation, and the median ICU length of stay prior to transfer to the weaning center was 30 (21-46) d. On admission to the weaning center, the median Medical Research Council (MRC) score was 36 (27-44). Time to decannulation was 9 (7-18) d after admission to the weaning center. The only factor independently associated with early decannulation was the MRC score on admission to the weaning center (odds ratio 1.16 [95% CI 1.06-1.31], P = .005). Two factors were independently associated with MRC gain ≥ 10: BMI (odds ratio 0.88 [95% CI 0.76-0.99], P = .045) and MRC on admission (odds ratio 0.91 [95% CI 0.82-0.98], P = .03. Three months after admission to the weaning center, 40 subjects (93%) were weaned from mechanical ventilation and 36 (84%) had returned home. MRC score at weaning center admission predicted both early decannulation and limb-muscle strength recovery.

Rehabilitation of Difficult-to-Wean, Tracheostomized Patients Admitted to Specialized Unit: Retrospective Analyses over 10-Years.

Rehabilitation outcomes of difficult-to-wean tracheostomized patients have been reported in relatively small case studies and described for a limited time span. This study describes the characteristics and clinical outcomes of a large cohort of tracheostomized patients admitted to a specialized weaning unit over 10 years. We retrospectively analyzed data collected from January 2010 to December 2019 on difficult-to-wean tracheostomized patients who underwent comprehensive rehabilitation. Clinical characteristics collected at admission were the level of comorbidity (by the Cumulative Illness Rating Scale—CIRS) and the clinical severity (by the Simplified Acute Physiology Score—SAPS II). The proportions of patients weaned, decannulated, and able to walk; the change in autonomy level according to the Bristol Activities of Daily Living (BADL) Scale; and the setting of hospital discharge was assessed and compared in a consecutive 5-year time period (2010–2014 and 2015–2019) subgroup analysis. A total of 180 patients were included in the analysis. Patient anthropometry and preadmission clinical management in acute care hospitals were similar across years, but the categories of underlying diagnosis changed (p < 0.001) (e.g., chronic obstructive pulmonary disease—COPD—decreased), while the level of comorbidities increased (p = 0.003). The decannulation rate was 45.6%. CIRS and SAPS II at admission were both significant predictors of clinical outcomes. The proportion of patients whose gain in BADL score increased ≥ 2 points decreased over time. This study confirms the importance of rehabilitation in weaning units for the severely disabled subset of tracheostomized patients. Comorbidities and severity at admission are significantly associated with rehabilitation outcomes at discharge.

Characteristics and Risk Factors of Children Requiring Prolonged Mechanical Ventilation vs. Non-prolonged Mechanical Ventilation in the PICU: A Prospective Single-Center Study.

BackgroundProlonged mechanical ventilation (PMV) has become an enormous challenge in intensive care units (ICUs) around the world. Patients treated with PMV are generally in poor health. These patients represent a select cohort with significant morbidity, mortality, and resource utilization. The status of children who have undergone PMV in China is unknown. Our goal is to investigate the prevalence and characteristics of pediatric patients with PMV, as well as the risk factors of PMV in the pediatric intensive care unit (PICU).MethodsThe subjects were divided into two groups. The PMV group(MV ≥ 14 days) and the non-PMV group(2 days < MV <14 days). The baseline characteristics, treatments, mortality and other results between the two groups were compared. The risk factors associated with PMV were evaluated using univariate and multivariable analyses.ResultsOf the 382 children enrolled, 127 (33.2%) received prolonged mechanical ventilation. The most common cause of MV in the PMV group was acute lung disease (48.0%), followed by acute circulatory system disease (26.0%), acute neurological disease (15.0%), postoperative monitoring (10.2%), and others (0.8%). Comorbidities were more prevalent among the PMV group (P = 0.004). The patients with PMV had a higher rate of premature birth (24.4 vs. 14.1%, P = 0.013) and higher PIM3 score at admission [5.6(3.0–9.9) vs. 4.1(1.7–5.5), P < 0.001]. The use of inotropes/vasopressors (63.8 vs. 43.1%, P < 0.001) was more common in patients with PMV compared with those in the non-PMV group. In the PMV group, the rate of extubation failure (39.4 vs. 6.7%, P < 0.001) was higher than the non-PMV group. The median hospital stay [35(23.0–50.0)d vs. 20(14.0–31.0)d, P < 0.001], PICU stay [22(15.0–33.0)d vs. 9(6.0–12.0)d, P < 0.001], hospitalization costs [¥391,925(263,259–614,471) vs. ¥239,497(158,723–350,620), P < 0.001], and mortality after 1-month discharge (22.0 vs. 1.6%, P < 0.001) were higher in the PMV group. Multivariate analysis revealed that age <1 year old, a higher PIM3 score at admission, prematurity, the use of inotropes or vasopressors, extubation failure, and ventilator mode on the first day of MV were associated with PMV.ConclusionsThe incidence and mortality of PMV in pediatric patients is surprisingly high. Premature infants or patients with severe disease or extubation failure are at higher risk of PMV. Patients with PMV exhibit a greater burden with regard to medical costs than those on non-PMV. It is important to establish specialized weaning units for mechanically ventilated patients with stable conditions.

Weaning in a Pandemic Situation - A Position Paper

ZusammenfassungDie logistischen und infektiologischen Besonderheiten und Erfordernisse in der Pandemie stellen die intensivmedizinischen Behandlungsteams vor außerordentliche Herausforderungen, die eine erfolgreiche Liberation von Patienten im prolongierten Weaning erschweren können. Gerade in der Pandemie gilt es daher, alle Potenziale zur Beatmungsentwöhnung und Dekanülierung von Patienten im prolongierten Weaning oder in der Langzeitbeatmung auszuschöpfen.Weaning-Zentren stellen Einheiten der intensivmedizinischen Betreuung mit besonderer Spezialisierung auf prolongiertes Weaning dar und sind integraler Bestandteil eines kontinuierlichen Versorgungskonzeptes dieser Patienten. Ein systematisches Weaning-Konzept in der Pandemie setzt strukturelle, personelle, apparative, infektiologische und hygienische Aspekte voraus.Im Mittelpunkt dieses Positionspapiers stehen als Ergänzung zur S2k-Leitlinie „Prolongiertes Weaning“ eine neue Klassifikation im prolongierten Weaning und zukünftig erforderliche Organisationsstrukturen für die Pandemie-Situation.Patienten der Kategorie A mit hohem Weaning-Potenzial bedürfen der strukturierten Respiratorentwöhnung in spezialisierten Weaning-Einheiten, um so die größtmögliche Chance auf erfolgreiches Weaning zu realisieren. Patienten der Kategorie B mit geringem oder aktuell nicht vorhandenem Weaning-Potenzial sollten verzögert nach einer Zwischenphase der weiteren Stabilsierung in einer außerklinischen Beatmungseinrichtung einen Weaning-Versuch erhalten. Patienten der Kategorie C ohne Weaning-Potenzial benötigen eine dauerhafte außerklinische Versorgung, alternativ eine palliativmedizinisch begleitete Beendigung der Beatmung. Die sich aus den 3 Kategorien ergebenden Aufgaben für die Weaning-Zentren werden im Positionspapier vertieft.Schließlich werden unter perspektivischer Betrachtung im Positionspapier folgende zukünftig denkbare Netzwerke und Register benannt: 1. lokal organisierte regionale Netzwerke von zertifizierten Weaning-Zentren, 2. ein zentrales, bundesweites Register der Weaning-Kapazitäten entsprechend dem DIVI-Register und 3. eine Registrierung der Patienten im schwierigen oder prolongierten Weaning.

Tracheostomy prevalence at Skilled Nursing Facilities

The incidence of chronically ill subjects with prolonged mechanical ventilation has significantly increased over the last decade. Many patients get discharge to Skilled Nursing Facilities with an artificial airway, which do not have the means to properly progress on weaning. In Portugal this prevalence is unknown. Our aim was to establish the prevalence of tracheostomized patients at SNF in the North of Portugal, characterizing these units and its population, in a cross-sectional study, through an online questionnaire answered on the same day. Of the 75 SNF, 30 answered: 13 long-term, 2 medium-term, 2 short-term, 12 had beds of both medium and long-term and 1 had the three typologies. 33 had tracheostomy ventilation (prevalence 3.36%), all admitted at long-term units, the majority transferred from previous hospital admission (n=27, 90%). Only one was under mechanical ventilation. The most frequent reason for tracheostomy placement was acute respiratory failure (n=10, 33.3%). The most commonly presented cannula was the fenestrated non-cuffed (n=17, 59%). Only 4 were performing occlusion training, 21 needed frequent secretion suctioning and 1 used the mechanical in-exsufflation. Regarding motor function, 16 (53.3%) were unable to achieve sitting balance and 20 (66.7%) had no orthostatic balance or walking ability. 14 (46.7%) had percutaneous endoscopic gastrostomy. Although low response rate may induce some bias, this study revealed a significant prevalence of tracheostomized patients at SNF. These facilities do not have the resources to safely and effectively progress on ventilatory weaning. It is essential to establish new referral criteria and create specialized weaning units.

Impact of multidrug-resistant bacteria on outcome in patients with prolonged weaning

BackgroundPneumonia and septic pneumonic shock are the most common indications for long-term mechanical ventilation and prolonged weaning, independent of any comorbidities. Multidrug resistant (MDR) bacteria are emerging as a cause of pneumonia or occur as a consequence of antimicrobial therapy. The influence of MDR bacteria on outcomes in patients with prolonged weaning is unknown.MethodsPatients treated in a specialized weaning unit of a university hospital between April 2013 and April 2016 were analyzed. Demographic data, clinical characteristics, length of stay (LOS) in the intensive care unit (ICU) and weaning unit, ventilator-free days and mortality rates were determined in prolonged weaning patients with versus without MDR bacteria (methicillin-resistant Staphylococcus aureus bacteria, [MRSA]; extended spectrum beta lactamase [ESBL]- and Gyrase-producing gram negative bacteria resistant to three of four antibiotic groups [3 MRGN]; panresistant Pseudomonas aeruginosa and other carbapenemase-producing gram-negative bacteria resistant to all four antibiotic groups [4 MRGN]). Weaning failure was defined as death or discharge with invasive ventilation.ResultsOf 666 patients treated in the weaning unit, 430 fulfilled the inclusion criteria and were included in the analysis. A total of 107 patients had isolates of MDR bacteria suspected as causative pathogens identified during the treatment process. Patients with MDR bacteria had higher SAPS II values at ICU admission and a significantly longer ICU LOS. Four MRGN P. aeruginosa and Acinetobacter baumanii were the most common MDR bacteria identified. Patients with versus without MDR bacteria had significantly higher arterial carbon dioxide levels at the time of weaning admission and a significantly lower rate of successful weaning (23% vs 31%, p < 0.05). Mortality rate on the weaning unit was 12.4% with no difference between the two patient groups. There were no significant differences between patient groups in secondary infections and ventilator-free days.ConclusionsIn patients with pneumonia or septic pneumonic shock undergoing prolonged weaning, infection with MDR bacteria may influence the weaning success rate but does not appear to impact on patient survival.

Hospital outcomes and long-term survival after referral to a specialized weaning unit

BackgroundProlonged invasive mechanical ventilation (IMV) is a frequent challenge, and an increasing number of patients are transferred from intensive care units to long-term acute care hospitals or specialized weaning units. There are few published data for discharge home rates, use of noninvasive ventilation (NIV), or long-term survival. MethodsA case-note and database review was conducted of patients admitted to a UK national specialized weaning unit for weaning from IMV between 1992 and 2012. Patients were grouped into diagnostic categories according to the predominant cause of weaning failure. Weaning outcomes and long-term survival were assessed according to diagnostic group and mode of ventilation on discharge. ResultsFour hundred and fifty-eight patients were transferred for weaning from IMV. Four hundred and seventeen (91%) survived to hospital discharge, of whom at least 343 (82%) were ultimately discharged to their own home. Three hundred and thirty (72%) weaned from IMV, of whom 142 weaned from all ventilation and 188 weaned to nocturnal NIV. Weaning success was highest for patients with chronic obstructive pulmonary disease and chest wall disorders. Median survival from unit discharge was 25 months (interquartile range 5–74), with the longest survival seen for patients discharged with nocturnal NIV [37 (12–81) months]. ConclusionsThese results confirm successful weaning outcomes for patients transferred to a specialized weaning and long-term ventilation service. In contrast to other service models, most patients achieved discharge to their own home.

Assessment of Sleep in Patients Receiving Invasive Mechanical Ventilation in a Specialized Weaning Unit.

A restful sleep is essential for regenerative processes and remains crucial for patients recovering from stressful periods in the intensive care unit. The current study aimed to assess sleep quality in critically ill patients receiving invasive mechanical ventilation within a specialized weaning unit in hospital. Tracheotomized subjects undergoing prolonged weaning from mechanical ventilation were included in the study. Polysomnography and gas exchange monitoring was performed during nocturnal ventilation. Subjective evaluation of sleep quality and health-related quality of life were also assessed. Nineteen subjects completed the study protocol. Sleep architecture was highly heterogeneous across individual subjects. Mean total sleep time (TST) was 273 ± 114min, sleep efficacy 70 ± 23%, slow-wave sleep 25.7 ± 18.4%/TST, rapid eye movement sleep 9.6 ± 7.5%/TST, and arousal index 18.7 ± 12.4/h. No significant difference in sleep quality was found between subjects with successful (N = 7) or unsuccessful (N = 12) weaning. Bicarbonate levels were negatively correlated both with sleep efficacy and sleep quality, that latter of which was subjectively assessed by the subjects using a visual analogue scale. Subjects who were undergoing prolonged weaning from mechanical ventilation and admitted to a specialized weaning unit, showed reduced sleep quality with preservation of high amounts of slow-wave sleep.

Differences between prolonged weaning patients from medical and surgical intensive care units

It is not clear whether patients entering a specialized, interdisciplinary weaning unit from surgical or medical intensive care units (ICU) distinguish substantially. The purpose of the present study was to assess differences in patients with prolonged weaning being referred from surgical and medical ICU. Data collected from April 2013 to April 2014 was conducted for retrospective analysis. Mortality rates, demographic data, clinical, and microbial differences in 150 patients with prolonged weaning were assessed (80 surgical and 70 medical). Surgical ICU referrals tended to be older (70.7 ± 11.3 vs. 67.3 ± 12.3, P = 0.051) and had fewer underlying pulmonary diseases (45% vs. 60%, P = 0.067). Sodium values at the time of referral to the weaning unit were significantly higher in surgical (147.1 ± 9.6) vs. medical (141.3 ± 6.7 mmol/l) patients (P < 0.001). Each 10-unit increase in sodium at the time of referral to the weaning unit was associated with a 2.5-day (95% CI -0.4, 5.4; P = 0.09) prolongation of stay in the weaning unit. Although significant differences in microbiological agents from tracheal aspiration were seen, the infection rate on the weaning unit was similar in both groups. There was no difference in weaning unit mortality between surgical and medical ICU patients (18% vs. 23%; P = 0.41). Few differences were found between patients being referred to a specialized weaning unit from surgical vs. medical ICUs. Besides differences in microbiological characteristics of tracheal secretions, there were also differences in sodium levels, which appear to influence on treatment duration.

Preadmission tracheostomy is associated with better outcomes in patients with prolonged mechanical ventilation in the postintensive care respiratory care setting.

Prolonged mechanical ventilation (PMV) is the most common situation where tracheostomy is indicated for intensive care unit (ICU) patients. However, it is unknown if this procedure confers survival benefits on PMV patients in a post-ICU setting. Patients who were admitted to the specialized weaning unit from 2005 to 2008 and received PMV were included in this study. On admission, data pertaining to patient characteristics, physiologic status, and type of artificial airway (tracheostomy vs. no tracheostomy) were obtained. Outcomes of tracheostomized and nontracheostomized patients were evaluated using multivariate Cox proportional hazards and propensity score-matching models. The primary outcome of interest was 1-year survival. A total of 401 patients (mean age 74.4years, 204 male) were identified. In multivariate analyses, higher Acute Physiology and Chronic Health Evaluation II score [hazard ratio (HR)=1.061, 95% confidence interval (CI)=1.016-1.107] and presence of comorbidities, including congestive heart failure (HR=1.562, 95% CI=1.119-2.181), malignancy (HR=1.942, 95% CI=1.306-2.885), and liver cirrhosis (HR=2.373, 95% CI=1.015-5.544), were independently associated with 1-year mortality. An association between having tracheostomy and a better 1-year outcome was observed (HR=0.625, 95% CI=0.453-0.863). The matched cohort study also demonstrated a favorable 1-year survival for tracheostomized patients, and these patients had significantly lower in-hospital mortality (24% vs. 36%, p=0.049) and risk of ventilator-associated pneumonia (10% vs. 20%, p=0.030) than nontracheostomized ones. Preadmission tracheostomy may be associated with better outcomes of PMV patients in a post-ICU respiratory care setting. The findings suggest that this procedure should be recommended before PMV patients are transferred to specialized weaning units.

Patients characteristics and outcomes of prolonged mechanical ventilation after critical illness transferred to a weaning unit

Recent trends seem to point out that growing numbers of patients requiring prolonged mechanical ventilation (PMV) and protracted weaning after critical illness with eventually account for a large portion of all Intensive Care Unit (ICU) cost and bed occupancy. Specialized Weaning Unit (WU), may facilitate weaning through focused multidisciplinary expert team, but due to considerable variability of interventions and organization outcomes remain unclear.

Prolonged weaning: From the intensive care unit to home

Weaning is the process of withdrawing mechanical ventilation which starts with the first spontaneous breathing trial (SBT). Based on the degree of difficulty and duration, weaning is classified as simple, difficult and prolonged. Prolonged weaning, which includes patients who fail 3 SBTs or are still on mechanical ventilation 7 days after the first SBT, affects a relatively small fraction of mechanically ventilated ICU patients but these, however, requires disproportionate resources. There are several potential causes which can lead to prolonged weaning. It is nonetheless important to understand the problem from the point of view of each individual patient in order to adopt appropriate treatment and define precise prognosis. An otherwise stable patient who remains on mechanical ventilation will be considered for transfer to a specialized weaning unit (SWU). Though there is not a precise definition, SWU can be considered as highly specialized and protected environments for patients requiring mechanical ventilation despite resolution of the acute disorder. Proper staffing, well defined short-term and long-term goals, attention to psychological and social problems represent key determinants of SWU success. Some patients cannot be weaned, either partly or entirely, and may require long-term home mechanical ventilation. In these cases the logistics relating to caregivers and the equipment must be carefully considered and addressed.

Prolonged weaning: From the intensive care unit to home

Weaning is the process of withdrawing mechanical ventilation which starts with the first spontaneous breathing trial (SBT). Based on the degree of difficulty and duration, weaning is classified as simple, difficult and prolonged. Prolonged weaning, which includes patients who fail 3 SBTs or are still on mechanical ventilation 7 days after the first SBT, affects a relatively small fraction of mechanically ventilated ICU patients but these, however, requires disproportionate resources. There are several potential causes which can lead to prolonged weaning. It is nonetheless important to understand the problem from the point of view of each individual patient in order to adopt appropriate treatment and define precise prognosis. An otherwise stable patient who remains on mechanical ventilation will be considered for transfer to a specialized weaning unit (SWU). Though there is not a precise definition, SWU can be considered as highly specialized and protected environments for patients requiring mechanical ventilation despite resolution of the acute disorder. Proper staffing, well defined short-term and long-term goals, attention to psychological and social problems represent key determinants of SWU success. Some patients cannot be weaned, either partly or entirely, and may require long-term home mechanical ventilation. In these cases the logistics relating to caregivers and the equipment must be carefully considered and addressed.

Inpatient and long‐term outcomes of individuals admitted for weaning from mechanical ventilation at a specialized ventilation weaning unit

Weaning from invasive mechanical ventilation (IMV) in specialized weaning units has been demonstrated to be safe and cost-effective. Success rates and outcomes vary widely, probably relating to patient factors and unit expertise. An audit was undertaken of patients admitted for weaning from IMV at the Austin Hospital Ventilation Weaning Unit (VWU) between March 2002 and January 2008. Weaning success, complications and both in-hospital and long-term mortality were examined and regression analysis was undertaken to examine factors related to these outcomes. Seventy-eight patients were admitted to the VWU after a median of 27 days of IMV at their referring centre. Weaning success rate (ventilator free or nocturnal non-invasive ventilation only) was 78.2% (n = 61). Inpatient mortality was 10.2% (n = 8) and serious complications were infrequent. Progressive neuromuscular disease (odds ratio 0.10) and sepsis during admission to the VWU (odds ratio 0.09) were predictive of weaning failure at discharge. Overall survival at 12 months following discharge from the VWU was 66.7% (n = 52) with most survivors residing in the community. Increasing age (hazard ratio 1.93), referral from rural or outer metropolitan centres (hazard ratio 3.57 and 2.37 respectively) and a diagnosis of chronic obstructive pulmonary disease were associated with increased long-term mortality. High rates of weaning success with infrequent complications and low mortality were achieved in this specialized non-intensive care unit-based weaning unit. The VWU may provide a useful template for the development of similar units elsewhere.

Overview of Improving Tolerance of Long-Term Mechanical Ventilation

In summary, advances in critical care and mechanical ventilation have resulted in an increased salvage of critically ill patients, a number of whom require long-term ventilation as a means of life support. In addition, the total number of patients receiving long-term ventilation has increased dramatically over the past couple of years, and they now are treated in many different locations throughout the health care delivery system (the intensive care unit, general medical floor, specialized weaning units, and the home). Moreover, patients who require long-term ventilation usually suffer from a complex blend of medical, physiologic, and psychological disorders that may impair tolerance of chronic ventilation. Careful evaluation and systematic treatment of psychological, medical, and physiologic disorders, coupled with optimized ventilator settings, may improve patients' tolerance and maximize their functional capacity.