Hypothyroidism and failure to wean in patients receiving prolonged mechanical ventilation at a regional weaning center

OBJECTIVE: Hypothyroidism is cited as an uncommon cause of ventilator-dependent respiratory failure. The objective of this study was to determine the incidence of hypothyroidism in patients with respiratory failure, receiving prolonged mechanical ventilation (PMV) with failure to wean, referred to a regional weaning center (RWC) for weaning. SETTING: RWC. DESIGN: Retrospective. METHODS: Medical records were reviewed of 173 patients admitted to this RWC between January 1999 and March 2002. One hundred forty patients were noted to have had screening serum thyroid stimulating hormone (TSH) levels obtained at admission. Records of these patients were further evaluated. The following data were abstracted: age, sex, body mass index, serum TSH levels, number of patients with previously diagnosed hypothyroidism, and number of patients with hypothyroidism diagnosed clinically and by laboratory tests following admission to the RWC. Primary outcome was liberation from PMV, which was defined as being off ventilatory support for > 1 week. Univariate analysis was performed to determine relation between serum TSH levels and outcome; p < 0.05 was deemed statistically significant. RESULTS: Of 140 patients studied, 67 were male (48%) and 73 were female (52%), with a mean age of 66 + 15 years (+/- SD). Only one patient had a history of previously diagnosed hypothyroidism. A clinical diagnosis of hypothyroidism was made in 4 of 140 patients (3%) following admission. Serum TSH levels ranged from 0.19 to 121 mU/L in the studied subjects. Seventeen of 140 patients (12%) had elevated serum TSH levels. Serum tri-iodothyronine and/or thyroxine levels confirmed diagnosis of hypothyroidism in four of these patients (3%). Patients with newly diagnosed hypothyroidism were treated with thyroid supplements, and three patients were liberated from PMV while one patient died from other medical causes. Of the 140 patients, 92 patients (67%) were liberated from PMV while 48 patients (33%) could not be weaned. Mean serum TSH levels were 4.2 + 13 mU/L in the liberated patients and 4 + 4.7 mU/L in the patients who could not be weaned (p = 0.25). CONCLUSION: Hypothyroidism is an uncommon cause of failure to wean in patients receiving PMV (with an incidence of 3%). However, it is a potentially treatable cause and should be considered in all patients who fail to wean. Serum TSH level does not appear to affect successful weaning from PMV.     

Course of weaning from prolonged mechanical ventilation after cardiac surgery

In order to determine the temporal pattern of weaning from mechanical ventilation for patients undergoing prolonged mechanical ventilation after cardiac surgery, we performed a retrospective review of 21 patients' weaning courses at our long-term acute care hospital. Using multiple regression analysis of an estimate of individual patients' percentage of mechanical ventilator support per day (%MVSD), we determined that 14 of 21 patients (67%) showed a statistically significant quadratic or cubic relationship between time and % MVSD. These patients showed little or no improvement in their ventilator dependence until a point in time when, abruptly, they began to make rapid progress (a "wean turning point"), after which they progressed to discontinuation of mechanical ventilation in a relatively short period of time. The other 7 patients appeared to have a similar weaning pattern, although the data were not statistically significant. Most patients in the study group weaned from the ventilator through a specific temporal pattern that is newly described herein. Data analysis suggested that the mechanism for the development of a wean turning point was improvement of pulmonary mechanics rather than improvement in gas exchange or respiratory load. Although these observations need to be confirmed by a prospective trial, they may have implications for weaning cardiac surgery patients from prolonged mechanical ventilation, and possibly for weaning a broader group of patients who require prolonged mechanical ventilation.     

Weaning from prolonged mechanical ventilation

The development of weaning failure and need for PMV is multifactorial in origin, involving disorders of pulmonary mechanics and complications associated with critical illness. The underlying disease process is clearly important when discussing mechanisms of ventilator dependence; interventions therefore must be tailored to individual patients. Unfortunately, the main conclusion that can be drawn from the sum of the studies investigating patients on PMV to date is that an evidence-based approach to weaning is not possible and more research needs to be done. New studies need to incorporate severity-of-illness scores and an assessment of principal and comorbid conditions to allow for comparison of the findings from different centers. The best approach to a patient requiring PMV after exclusion of easily treatable conditions is not known. The literature regarding both acute and chronic cases suggests that a systematic approach to weaning involving the participation of multiple caregivers, including nurses, physicians, and respiratory, physical, and speech therapists facilitates liberation from MV. Although a gradual decrement in ventilator support would seem prudent, Scheinhorn et al have begun to identify a subpopulation of patients who can tolerate an acceleration of the weaning process. Given the known complications associated with MV, it is crucial that further research be performed to identify patients as soon as they are capable of breathing spontaneously. The literature demonstrates through multiple studies that satisfactory patient outcomes are attainable and can be achieved at LTAC facilities in a more cost-effective manner than in an ICU setting. The trend toward the concentration of patients into specialized regional weaning centers should facilitate the research process and continue to improve outcomes in this population.     

Post-ICU mechanical ventilation at 23 long-term care hospitals: a multicenter outcomes study

STUDY OBJECTIVES: This multicenter study was undertaken to characterize the population of ventilator-dependent patients admitted to long-term care hospitals (LTCHs) with weaning programs, and to report treatments, complications, weaning outcome, discharge disposition, and survival in these patients. DESIGN: Observational study with concurrent data collection. SETTING: Twenty-three LTCHs in the United States. PATIENTS: Consecutive ventilator-dependent patients admitted over a 1-year period: March 1, 2002, to February 28, 2003. RESULTS: A total of 1,419 patients were enrolled in the Ventilation Outcomes Study. Median age of patients was 71.8 years (range, 18 to 97.7 years). Patients averaged 6.9 procedures and treatments during the LTCH hospitalization; median length of stay was 40 days (range, 1 to 365 days). Seven of the 10 most frequent complications treated at the LTCH were infections; congestive heart failure and diabetes mellitus were the most common comorbidities requiring treatment. Outcomes of weaning attempts, scored at LTCH discharge, were 54.1% weaned, 20.9% ventilator dependent, and 25.0% deceased. Median time to wean (n = 766) was 15 days (range, 7 to 30 days). Discharge disposition included 28.8% to home, 49.2% to rehabilitation and extended-care facilities, and 19.5% to short-stay acute hospitals. Nearly one third of patients were known to be alive 12 months after admission to the LTCH. CONCLUSIONS: Patients admitted to LTCHs for weaning attempts were elderly, with acute-on-chronic diseases, and continued to require considerable medical interventions and treatments. The frequency and type of complications were not surprising following prolonged and aggressive ICU interventions. In the continuum of critical care medicine, more than half of ventilator-dependent survivors of catastrophic illness transferred from the ICU were successfully weaned from prolonged mechanical ventilation in the setting of an LTCH.     

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.     

Predicting 3-day and 7-day outcomes of weaning from mechanical ventilation.

OBJECTIVE: To determine the correlation of acute physiology and chronic health evaluation (APACHE) II score and various weaning indexes (WIs) with 3- and 7-day weaning outcomes. DESIGN: Prospective, observational. SETTING: The medical ICU of a teaching, urban hospital. METHODS: The study included 118 adults referred for weaning from mechanical ventilation (MV). Critical care physicians, critical care nurses, and respiratory care practitioners were asked to predict whether it would take < or =3 days, 4 to 7 days, or > or =8 days to wean each patient from MV. The WIs and APACHE II scores were measured or calculated. The causes of respiratory failure, the duration of MV before initiating weaning assessment, and the 3- and 7-day weaning outcomes were obtained. Significance was set at p<0.05. RESULTS: The most common causes of respiratory failure were pneumonia (38 cases) and acute exacerbation of COPD (29 cases). Fifty-seven patients (48%) were successfully weaned from MV within 3 days of weaning assessment, and 67 (57%) were weaned within 7 days. The percentages of correct prediction of 3-day weaning outcome by critical care physicians, critical care nurses, and respiratory care practitioners were 64%, 62%, and 59%, respectively; for 7-day weaning outcome, 60%, 64%, and 58%, respectively. The successfully weaned groups had significantly lower APACHE II scores and higher maximal inspiratory pressures than the unsuccessfully weaned (failure) groups. There were no significant differences between the two groups for the remaining indexes, including rapid shallow breathing, dynamic compliance, static compliance, spontaneous respiratory rate, and the ratio of PaO2 to the fraction of inspired oxygen. CONCLUSIONS: The overall severity of illness as assessed by APACHE II score correlates better with 3- and 7-day weaning outcome than the published WIs.     

Criteria for weaning from prolonged mechanical ventilation

We retrospectively studied 11 instances of patients requiring prolonged mechanical ventilation. Their spontaneous ventilatory measurements were not useful in judging their ability to wean, since these measurements did not change from the period of unsuccessful weaning to the period of progressive weaning from the ventilator. An adverse factor score and a ventilator score were created to evaluate underlying medical and respiratory problems related to ability to wean. Each score and the sum of the two scores separated patients between unsuccessful and successful weaning periods. We also found that the course and the duration of the entire weaning process could be predicted once progressive weaning had begun. We conclude that the adverse factor score and ventilator score correlate with the ability of patients receiving prolonged mechanical ventilation to wean.     

Use of inspiratory muscle strength training to facilitate ventilator weaning: a series of 10 consecutive patients

BACKGROUND AND PURPOSE: We instituted a low-repetition, high-intensity inspiratory muscle strength training (IMST) program and progressively longer spontaneous breathing periods (SBPs) in a group of medically complex patients who were dependent on mechanical ventilation (MV) and had failed to wean. CASE DESCRIPTIONS: IMST was provided to 10 consecutive patients (four men, six women; mean [+/- SD] age, 59 +/- 15 years) who had failed to wean from MV by conventional methods for >or= 7 days. Prior to initiating IMST, patients had received MV support for a mean of 34 +/- 31 days. Daily IMST consisted of four sets of six breaths through a threshold inspiratory muscle trainer that had been set at an intensity to yield an exertion rating of 6 to 8 of a maximal value of 10. At the start of IMST, patients were tolerating 2.1 +/- 3.4 consecutive hours of SBPs. The duration of the SBPs was increased daily, as tolerated. Patients were considered to have been weaned from MV when they were able to breathe without MV support for 24 consecutive hours. OUTCOMES: After 44 +/- 43 days of IMST, 9 of 10 patients were weaned from MV. The initial IMST pressure was 7 +/- 3 cm H(2)O, and it was increased to 18 +/- 7 cm H(2)O (p < 0.05). DISCUSSION: These results indicate that an IMST protocol that produces significant increases in threshold training pressure, in combination with progressive SBPs, aids in weaning patients from MV. Although promising, these preliminary observations must be tested in a controlled trial.     

应用体外膜式人工肺氧合治疗体外循环脱机困难38例的临床经验

目的:总结心脏外科术后脱离体外循环机困难的患者接受体外膜式氧合(ECMO)治疗的临床经验。方法:2004年9月至2010年12月北京安贞医院共38例患者行ECMO治疗,男性29例,女性9例,年龄6个月～74岁,ECMO辅助时间6～280 h,平均65 h。结果:ECMO成功脱机20例(52.6%),其中14例(36.8%)痊愈,6例脱机后死亡;18例未能脱机均死亡。结论:ECMO对于体外循环脱机困难患者是一种有效的辅助措施,及早应用并积极防治ECMO并发症可提高院内生存率。     

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.     

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.     

An Accelerated Hemostasis Protocol following Transradial Cardiac Catheterization Is Safe and May Shorten Hospital Stay: A Single‐Center Experience

Introduction: Hemostasis following transradial cardiac catheterization is achieved by external pressure application using various devices, TR Band? being one. There is no standardized protocol for the application and removal of such devices. Objective: To assess the safety and feasibility of a more rapid (1 hour) initiation of TR Band? removal ([time to wean] TTW1) compared to a recommended 2 hour protocol (TTW2) in a controlled prospective study. Methods: 100 consecutive outpatients undergoing diagnostic transradial cardiac catheterization prospectively underwent an accelerated initiation of post‐procedure TR Band? removal (TTW1 group). The controls were a random historical cohort of 25 patients who had the conventional 2 hours to wean approach (TTW2). Results: The mean age was 62 years with a mean BMI of 29 kg/m²; 51% were hypertensive and 9% were on warfarin anticoagulation. As defined, the median times to TR Band? weaning were 60 minutes and 120 minutes for TTW1 and TTW2 groups, respectively, p < 0.001. TTW1 patients had more oozing leading to insignificant delay in the weaning process (16% vs 4% in the TTW2 group, p = NS). The total time, however, from TR Band? application to removal was significantly shorter in the TTW1 group compared to TTW2 (median of 120 minutes [mean 127] vs 180 minutes [mean 187], p < 0.001). There were no differences in any prespecified complications. Conclusion: A rapid 1‐hour commencement of TR Band? weaning following transradial diagnostic cardiac catheterization appears to be safe. It shortens the overall device removal time and may shorten hospital stay in day‐case procedures.     

Oxygen and ventilator weaning during inpatient pediatric pulmonary rehabilitation

Rates of oxygen and ventilator weaning, and factors related to successful weaning in inpatient pediatric pulmonary programs for infants and young children, have not been frequently reported in the literature. A retrospective review was conducted of 34 infants and toddlers with either a diagnostic condition of prematurity (PM) or congenital anomalies/neuromuscular disease (CA/NM) discharged from an inpatient pulmonary program. These cases represent 67 hospital admission-discharge episodes over a 6-year period. The rate of successful oxygen weaning (decrease to 0 hr per day) and ventilator weaning (decrease to <12 hr per day) and predictive factors related to successful ventilator weaning per admission-discharge episode were examined. Successful oxygen weaning was achieved during 24% and successful ventilator weaning was achieved during 30% of the admission-discharge episodes. No significant relationships were found between the selected demographic and clinical factors and oxygen weaning. Using a logistic regression model, the major variable associated with successful ventilator weaning per admission-discharge episode was diagnostic condition. Age at admission and the presence of comorbidities added slightly to the prediction model. The overall model yielded 86% accuracy for predicting a decrease in ventilator hours. However, projecting in which episodes children will not be weaned (negative predictive value = 88.9%) was more accurate than projecting in which episodes children will be weaned (positive predictive value = 73.3%). Although the program achieved a relatively low rate of successful ventilator weaning, children with a diagnostic condition of prematurity were more likely to be successfully weaned during inpatient pulmonary rehabilitation.     

Airway occlusion pressure. An important indicator for successful weaning in patients with chronic obstructive pulmonary disease

The objective of this study was to determine whether airway occlusion pressure (P0.1) is a useful predictor for successful weaning during discontinuation of assisted ventilation (AV) in patients with chronic obstructive pulmonary disease (COPD). We studied 12 patients with COPD receiving AV with maximal inspiratory pressure (MIP) less than or equal to -20 cm H2O and FVC greater than or equal to 10 ml/kg. The P0.1, VT, frequency, mean inspiratory flow rate (VT/TI), inspiratory time to total breath cycle duration (TI/Ttot), and arterial blood gases were determined just prior to weaning, within 5 min after discontinuing AV (Time 0), and at 30, 60, 90, 120, 180, and 240 min. Five of the 12 patients failed to wean, defined as requiring AV within 24 h after discontinuing AV. At Time 0, all patients who subsequently failed to wean had a P0.1 of greater than 6 cm H2O, and those who were successfully weaned had a P0.1 of less than 6 cm H2O (p less than 0.001), although the arterial blood gas determinations were comparable in both groups. Throughout the study period, P0.1 in the patients who failed to wean was persistently higher than in the successfully weaned patients. Despite the high P0.1, VT and VT/TI decreased significantly at the termination of the study compared with those at Time 0 in 3 of the patients who failed to wean. Tachypnea was not useful in predicting failure to wean. The TI/Ttot in the patients who failed to wean was persistently lower than in the successfully weaned patients. We conclude that P0.1 is an important indicator for successful weaning.     

Long-term outlook in quadriplegic patients with initial ventilator dependency

Traumatic spinal cord injuries frequently result in respiratory insufficiency. With intensive medical support, many of these patients live productive lives in spite of severe neurologic deficit. A ten-year review of ventilator-dependent quadriplegic patients at Craig Rehabilitation Hospital was undertaken to determine the number of patients who could be weaned from mechanical ventilation and their long-term survival rate. Ventilator dependency is defined as requiring continuous mechanical ventilatory support for 30 or more days. Of the 134 patients that were included in the study, 76 were weaned during initial hospitalization. Factors which adversely affected ability to wean include: 1) high level of neurologic injury, 2) age greater than 50 years, and 3) other associated injuries. Of the ventilator-dependent patients surveyed after leaving the hospital, survival rate at one year was 90 percent (37 of 41), 56 percent (14 of 25), at three years and 33 percent (7 of 21) at five years. We conclude that vigorous medical support and maximal efforts to wean these patients from mechanical ventilation should be undertaken to: minimize the financial and emotional burden of long term institutional care, reduce ventilator dependency, and improve overall quality of life.     

Awake extracorporeal membrane oxygenation in patients with severe postoperative acute respiratory distress syndrome

Background

A clinical trial of extracorporeal membrane oxygenation (ECMO) as an alternative ventilator tool is being performed as a new indication for ECMO. The purpose of this study was to evaluate the feasibility of awake ECMO to increase the success rate of weaning patients from ECMO and ventilator care during treatment of postoperative severe acute respiratory distress syndrome (ARDS).

Methods

We retrospectively analyzed the clinical reports of 10 patients who underwent awake ECMO due to postoperative ARDS between August 2012 and May 2015. We analyzed patient history, the partial arterial pressure of oxygen (PaO₂)/fraction of inspired oxygen (FiO₂) ratio, and patient outcome.

Results

Seven patients (70%) were weaned from ECMO without difficulty; one patient failed to maintain awake ECMO, was re-intubated after 2 days of awake ECMO, and was re-tried on awake ECMO after 4 days of ventilator care. We weaned that patient from ECMO 2 days later. We weaned a total of eight patients (80%) from awake ECMO. The ECMO duration of surviving patients was 9.13±2.2 days (range, 6–12 days), and mean ventilator use duration was 6.8±4.7 days (range, 2–16 days). Two cases failed awake ECMO and died due to disease aggravation.

Conclusions

Awake ECMO was a useful weaning strategy after severe postoperative ARDS, as it avoids long-duration use of mechanical ventilation. Additionally, it is possible for patients to breathe spontaneously, which might prevents respiratory muscle dystrophy.     

Family presence and surveillance during weaning from prolonged mechanical ventilation

OBJECTIVES: The research was designed to describe the care and communication processes during weaning from long-term mechanical ventilation (LTMV). A portion of those findings, specifically, how family members interact with the patient and respond to the ventilator and associated intensive care unit bedside equipment during LTMV weaning, are reported here. METHODS: Ethnography was conducted in a medical intensive care unit (MICU) and step-down MICU following 30 adults who were being weaned from LTMV (>4 days). Data collection involved field observations conducted from November 2001 to July 2003; interviews with patients, family members, and MICU clinicians; and clinical record review. RESULTS: Family members were present at the patients' bedside during 46% of weaning trials and interacted with patients through touch, talking, and surveillance. Families' bedside surveillance activities were interpretive of numeric monitor displays and laboratory values, protective of patient safety and comfort, and often focused exclusively on weaning. Interpretive language and surveillance were learned from and imitative of clinician behaviors. Clinicians characterized the family's presence as helpful, a hindrance, or having no effect on the weaning process. Quantitative analysis using random coefficient modeling examining the effect of family presence on length of weaning trials showed significantly longer daily weaning trials when families were present (P < .0001). CONCLUSION: Critical care clinicians influence families' acquisition of interpretive surveillance skills at the bedside of patients who are being weaned from LTMV. This study provides a potentially useful conceptual framework of family behaviors with long-term critically ill patients that could enhance the dialogue about family-centered care and guide future research on family presence in the intensive care unit.     

Early mobilization of LVAD recipients who require prolonged mechanical ventilation

Early mobilization and aggressive physical therapy are essential in patients who receive left ventricular assist devices (LVADs) due to long-term, end-stage heart failure. Some of these patients remain ventilator dependent for quite some time after device implantation. We report our regimen of mobilization with the aid of a portable ventilator, in patients with cardiac cachexia and LVAD implantation. Further, we describe the specific physical therapy interventions used in an LVAD patient who required prolonged mechanical ventilation after device implantation. The patient was critically ill for 5 weeks before the surgery and was ventilator dependent for 48 days postoperatively. There were significant functional gains during the period of prolonged mechanical ventilation. The patient was able to walk up to 600 feet by the time he was weaned from the ventilator and transferred out of the intensive care unit. He underwent successful heart transplantation 6 weeks after being weaned from the ventilator We believe that improving the mobility of LVAD patients who require mechanical ventilation has the potential both to facilitate ventilator weaning and to improve the outcomes of transplantation.     

Significant tracheal obstruction causing failure to wean in patients requiring prolonged mechanical ventilation: a forgotten complication of long-term mechanical ventilation

INTRODUCTION: Modern low-pressure, high-volume cuffed tracheotomy tubes have been shown to decrease tracheal injury. However, injury still occurs in patients requiring prolonged mechanical ventilation and prevents weaning, delays decannulation, prolongs hospitalization, and may totally obstruct the airway. We describe 37 patients, including the first reported case of failure to wean due to tracheal obstruction. METHODS: Over a 3-year period, from September 1994 to August 1997, the hospital records of 37 patients requiring prolonged mechanical ventilation (> 4 weeks) and found to have tracheal obstruction were reviewed retrospectively. They were a subgroup of 756 patients admitted to hospitals during the same period. The average endotracheal/tracheostomy cannulation time was 3 weeks/12 weeks (range 2 to 4 weeks/8 to 14 weeks). Average age was 76 years (range, 34 to 81). Underlying diseases included COPD, postcoronary artery bypass graft surgery, postpneumonectomy, severe pneumonia, acute lung injury, and ischemic heart disease. RESULTS: All 37 patients who initially failed to wean had difficulty in breathing and developed intermittent high peak airway pressures either early or during the weaning process or just on being ventilated. The insertion of a longer tracheal tube bypassed the obstruction, reestablished the airway, decreased peak airway pressures, and allowed the patient to breathe more easily. The obstruction was confirmed on bronchoscopy. Treatment consisted of either placement of a longer tracheal tube (34 of 37 patients) or placement of a tracheal stent. All but two of the patients (5.4%) were able to be weaned within a week. The two patients who still failed to be weaned were subsequently diagnosed as having amyotrophic lateral sclerosis. CONCLUSION: Tracheal obstruction in patients requiring prolonged mechanical ventilation prevented weaning. Reestablishment of the airway with a longer tracheal tube or tracheal stent allowed most of the patients to be weaned.