Management and prognosis of patients requiring prolonged mechanical ventilation in long-term acute care hospitals (LTACH)

INTRODUCTION — 

A small proportion of patients in the intensive care unit (ICU) are unable to be liberated from mechanical ventilation by 21 days, which is termed prolonged mechanical ventilation (PMV). Such patients require a tracheostomy and when stable, are transferred to a long-term acute care hospital (LTACH) for ventilator weaning. This population often also has several chronic medical issues and complications that need to be addressed during their course in the LTACH.

The definition, evaluation, management, and prognosis of patients who undergo PMV are discussed in this topic. The evaluation and management of patients who have difficulty weaning from mechanical ventilation in the ICU are discussed separately. (See "Management of the difficult-to-liberate adult patient in the intensive care unit".)

DEFINITION — 

The Centers for Medicare and Medicaid Services in the United States define PMV as >21 days of mechanical ventilation for at least six hours per day [1]. However, many studies have used variable durations to define PMV.

The definitions of simple weaning, difficult-to-wean, and prolonged weaning in the intensive care unit are provided separately. (See "Management of the difficult-to-liberate adult patient in the intensive care unit", section on 'Definition and incidence'.)

EPIDEMIOLOGY — 

It is estimated that between 4 and 13 percent of mechanically ventilated patients in the United States require PMV [2,3], such that 7250 to 11,400 patients are undergoing PMV at any one time [2].

PATHOGENESIS — 

The imbalance created by an increased respiratory load and decreased respiratory muscle performance appears to be responsible for most cases of prolonged ventilatory dependence [4-6]:

●Increased respiratory muscle load – In a study of 31 mechanically ventilated patients with chronic obstructive pulmonary disease, findings suggestive of an increased respiratory muscle load were more apparent among the 17 patients who failed a spontaneous breathing trial (SBT) compared with those who passed an SBT and underwent successful extubation [4].

●Decreased respiratory muscle performance – In one study, 31 ventilator-dependent patients demonstrated increased respiratory drive (ie, decrease in the airway opening pressure) and decreased respiratory muscle strength (ie, diminished maximum transdiaphragmatic pressure), both of which are suggestive of decreased respiratory muscle performance [6]. Diaphragmatic dysfunction may be present in up to 3 percent of patients undergoing PMV and may be associated with delayed weaning when compared with patients who undergo PMV but do not have diaphragmatic dysfunction [7].

Mechanical ventilation itself may contribute to decreased respiratory muscle performance [8]. For example, diaphragm proteolysis has been shown to occur within 18 to 69 hours of controlled mechanical ventilation [9]. Respiratory muscle weakness is more prevalent than limb muscle weakness after initiation of mechanical ventilation [10]. However, the degree to which these observations contribute to the need for PMV is unknown. (See "Clinical and physiologic complications of mechanical ventilation: Overview", section on 'Respiratory muscle weakness'.)

Decreased central respiratory drive (ie, due to medications or central nervous system disease) is often considered a potential contributor to PMV. However, evidence suggests that this is uncommon [4,5] since most patients who fail to wean actually have an increased central respiratory drive.

INITIAL EVALUATION — 

When patients are admitted to LTACHs, we take a detailed history and examination and obtain routine laboratory tests and (when indicated) condition-specific testing. Intensive care unit (ICU) factors that may predict patients who are likely to need PMV are discussed separately (table 1). (See "Management of the difficult-to-liberate adult patient in the intensive care unit", section on 'Identify and correct the causes limiting successful liberation'.)

History and examination — Our approach is the following:

●Acute critical illness – We obtain a comprehensive history of the patient's acute critical illness, for which, a review of hospital records and/or discussion with the admitting clinician is needed. This includes the following:

•Illness timeline.

•Reason for and duration of the ICU admission.

•Type and severity of complications that occurred during the acute phase of critical illness (eg, venous thromboembolism, infections, kidney injury, cardiac complications, delirium, and complications of mechanical ventilation). (See "Clinical and physiologic complications of mechanical ventilation: Overview".)

•Any administered treatments or surgeries.

•Any necessary follow-up required for underlying illness, complications, or incidental findings on imaging.

•Tracheostomy type, size, date of insertion, and last change. (See "Tracheostomy in adults: Techniques and intraoperative complications", section on 'Tube types'.)

•Ventilator settings used for spontaneous breathing trials (SBTs) in the ICU, outcomes of such trials, and reason(s) for failure.

●Pre-existing illnesses and medication reconciliation – We review the patient's pre-existing medical illnesses and medication list. A comparison of pre- versus post-acute critical illness conditions helps evaluate if current symptoms are new or possibly related to the presence or worsening of pre-existing medical illnesses. Similarly, medication reconciliation helps determine whether medications need to be restarted (eg, anti-depressants) or discontinued. The involvement of pharmacists may facilitate this process [11].

●Current symptoms and signs – We obtain a brief history of current symptoms (eg, fatigue, dyspnea, chest pain, cough, sputum); physical limitations; functional disability; impact of symptoms on activities of daily living; and symptoms of anxiety/depression, posttraumatic stress disorder, and cognitive impairments. Collateral history from family or caregivers may be needed to obtain an accurate assessment. (See "Comorbid anxiety and depression in adults: Epidemiology, clinical manifestations, and diagnosis" and "Posttraumatic stress disorder in adults: Epidemiology, pathophysiology, clinical features, assessment, and diagnosis" and "Evaluation of cognitive impairment and dementia".)

All patients should undergo routine examination. We also specifically examine and document the location, type, and size of their tracheostomy and feeding tube; any wounds (surgical, decubitus, or other); and external hardware (eg, intravenous access, chest catheters, urinary catheters, and ostomy bags).

Neurologic assessment, musculoskeletal assessment, and determination of volume status may also be relevant in patients requiring PMV.

Laboratory testing and imaging — We generally obtain the following:

●Complete blood count and differential

●Blood chemistries, including electrolytes, blood urea nitrogen and serum creatinine

●Arterial (or venous) blood gas

●Liver function studies, including serum albumin

●Coagulation studies

●Chest radiography

●Electrocardiography

●Urine analysis and culture

Additional laboratory and imaging tests are appropriate for select patients. As examples:

●If the cause for PMV is unclear, we measure a brain natriuretic and obtain an echocardiogram.

●If there is concern for diaphragmatic paralysis, diaphragm fluoroscopy or ultrasound may also be warranted.

●If underlying interstitial lung disease is a consideration or an incidental mass was found during the acute admission, chest computed tomography is appropriate.

●For patients with endocarditis, follow-up blood cultures and imaging may be required.

Infection control — Many patients admitted to LTACHs require isolation due to colonization or infection with a resistant microorganism. Meticulous attention needs to be paid to infection control, which can be a challenge in LTACHs.

MANAGEMENT — 

Management largely focuses on optimizing underlying illnesses, weaning from mechanical ventilation, rehabilitation (encompassing physical, nutritional, occupational, and speech-related issues), and managing complications that arise periodically in this population.

Optimizing medical issues — In patients with PMV, several medical issues, either pre-existing or due to the acute critical illness, may contribute to PMV and deconditioning. Concurrent treatment of these issues is critical for success.

Medical issues that exist in this population are wide and varied, most commonly pulmonary in etiology but also psychological, cognitive, neurologic, oncologic, traumatic, and surgical. Pulmonary conditions include chronic obstructive pulmonary disease (42 percent), obstructive sleep apnea/obesity hypoventilation (8.2 percent), interstitial lung disease (2.7 percent), post-lung resection (2.7 percent), pulmonary vascular disease (<2 percent), and bronchiectasis (<2 percent) [12,13]. The involvement of subspecialists at the in- or out-patient level is often required.

Sleep-disordered breathing (SDB) may be underrecognized in this population [14], although the optimal approach to investigation and diagnosis is unknown. We typically try to maintain normal circadian rhythm during sleep and have a low threshold to suspect SDB following decannulation using the usual principles in the general population. If SDB was a pre-existing diagnosis, we identify potential barriers to successful therapy prior to decannulation (eg, mask intolerance). (See "Clinical presentation and diagnosis of obstructive sleep apnea in adults".)

Ventilator liberation strategies — The optimal protocol for ventilator liberation in patients who require PMV is unknown and is poorly studied. In general, the principles behind weaning in this population are similar to the acute intensive care unit (ICU) population except weaning is drawn out over a longer period of time (days, weeks, and sometimes months). We agree with guidelines issued by a collective task force that recommends slow-paced, once-daily weaning with a gradual lengthening of spontaneous breathing trials (SBTs) [15].

Initial strategies for mechanical ventilation liberation in patients who received short-term mechanical ventilation in the ICU are presented elsewhere. (See "Initial weaning strategy in mechanically ventilated adults".)

Patient selection — We initiate liberation trials when the following criteria are met (table 2):

●Evidence for reversal or stabilization of the underlying cause of respiratory failure

●Adequate oxygenation (eg, partial arterial oxygen tension [PaO₂]/fraction of inspired oxygen [FiO₂] ratio >150 on ventilator settings that include ≤5 cm H₂O of positive end-expiratory pressure and an FiO₂ ≤0.4)

●Adequate pH (eg, ≥7.25)

●Hemodynamic stability (eg, no active myocardial ischemia or clinically significant hypotension, no or low-dose vasopressor medication)

●Ability to initiate an inspiratory effort

Ventilator liberation method — We initiate ventilator liberation using pressure-supported SBTs (PSV-SBTs), which is based upon our experience and similar to that in acute ICU patients who have been mechanically ventilated for <3 weeks (see "Initial weaning strategy in mechanically ventilated adults", section on 'Daily spontaneous breathing trials (SBTs)'). As an alternative, tracheostomy collar SBTs are also an option, especially in those who have had successful low-level PSV-SBT prior to LTACH admission.

The initial settings and duration of SBT vary and should be individualized. Selecting initial settings depends upon the patient's tolerance of previous SBTs in the ICU and institutional practice. In general, it is prudent to perform quick bedside testing, often done by respiratory therapy staff, to select initial settings. At the bedside, we ideally initiate a low-level PSV-SBT (eg, pressure support level between 5 and 8 cm H₂O) or tracheostomy collar SBT for a few minutes. Criteria used to assess patient tolerance during SBTs are similar to those in the acute care setting and are listed in the table (table 3).

●Successful SBT – For those who appear comfortable on initial settings, we proceed with an SBT.

The length of the initial SBT is generally continued for as long as tolerated, most often an hour (longer if the patient is known to have tolerated an SBT for a few hours prior to admission). After the SBT, prior ventilator settings are resumed until the next day, when the patient is reassessed for another SBT.

Once patients can tolerate an SBT for a limited period, we gradually increase the duration of the daily SBT [1]. For example, a typical sequence for SBT duration might be 1 hour (step 1), 2 hours (step 2), 4 hours (step 3), 6 hours (step 4), 8 hours (step 5), 10 hours (step 6), 12 hours (step 7), 16 hours (step 8), 20 hours (step 9), and 24 hours (step 10). However, the rate of progression through the steps of weaning is individualized and in reality, largely dependent upon the patient's performance during each SBT. For example, some patients may extend trial duration by an hour or more per day until they reach 24 hours per day while in others with limited SBT tolerance, we may extend trial duration every few days or few weeks.

Once low-level PSV-SBT is tolerated for 24 hours, we transition to a tracheostomy collar, which allows the patient to breathe spontaneously and to receive oxygen supplementation, if necessary. Tracheostomy collar SBTs are extended in a similar step-wise fashion. Once the patient can tolerate 24 hours of a tracheostomy collar, we consider preparing for tracheostomy decannulation, often starting with SBTs using a speaking valve or "capping." The procedure for decannulation is provided separately. (See "Tracheostomy: Postoperative care, maintenance, and complications in adults", section on 'Decannulation'.)

●SBT failure – For patients who fail an initial low-level PSV-SBT at the bedside, we may start with a higher degree of pressure support (eg, 10 to 12 cm H₂O, titrated to achieve patient tolerance) and proceed with those settings for a few hours (eg, two to four hours). Similarly, for those who fail tracheostomy collar SBTs, we transition to PSV-SBT.

With each successive daily SBT, we attempt to sequentially wean the pressure support level to ≤8 cm H₂O before extending the duration, although practice varies in this regard (ie, some clinicians extend the time before reducing the degree of pressure support).

For patients who fail an SBT at any point, we resume their prior ventilation settings and address any potential reasons for failure before resuming SBTs. Once identified and corrected, we resume SBT trials at a previous setting and duration that was successful. Reasons for failure are similar to those in the ICU (table 4) and are discussed separately. (See "Management of the difficult-to-liberate adult patient in the intensive care unit", section on 'Identify and correct the causes limiting successful liberation'.)

A patient is considered permanently ventilator-dependent when three months of weaning attempts have consistently failed [15].

Our approach to PSV- or tracheostomy collar SBTs is based upon the success achieved with SBT weaning in the acute ICU population and our experience (see "Initial weaning strategy in mechanically ventilated adults", section on 'Evidence supporting daily SBTs'). However, limited data in the PMV population suggest that PSV-SBTs may prolong ventilation compared with tracheostomy collar SBTs. In a randomized trial of patients with PMV, patients who received unassisted breathing trials through a tracheostomy collar had a shorter median time to ventilator liberation compared with patients who underwent low-level PSV-SBT (15 days [interquartile range (IQR) 8 to 25 days] versus 19 days [IQR 12 to 31 days]), although 6-month and 12-month mortality did not differ [16]. However, further studies are needed to determine the generalizability of these findings.

Several studies suggest that protocol-driven ventilator liberation with frequent reassessment is beneficial (eg, nurse or respiratory therapist [RT]-driven protocols) [1,17-19]. As examples:

●In an observational study that evaluated 252 patients requiring PMV, use of a RT-driven liberation protocol was associated with a shorter median duration of mechanical ventilation compared with historical controls (17 versus 29 days) [18].

●In another retrospective case-control study of 51 patients, an RT-driven protocol reduced the time to mechanical ventilation liberation from 16.7 days before protocol implementation to 7.7 days after protocol implementation.

One purported advantage of such protocols is that frequent reassessment during SBTs may alleviate patient (and family or caregiver) fears, although this observation remains unproven.

Airborne precaution-specific issues — Airborne precaution-specific issues include the following:

●Initial PSV-SBT trials are typically performed through a closed-loop system, which is considered non-aerosol-generating.

●Spontaneous breathing through a tracheostomy collar is an open system. As a result, some institutions consider tracheostomy collar trials an aerosol-generating procedure (AGP), although it remains controversial and practice is variable. Regardless, tracheostomy collar SBTs should be performed in an airborne isolation room. An alternative includes using a portable high-efficiency particulate air filter to generate negative pressure in a room during a tracheostomy collar SBT. A surgical mask over the tracheostomy itself may also theoretically limit droplet spread, but is not ideal.

●Breathing trials using a speaking valve or capping are considered AGPs, so airborne precautions are warranted. However, once a speaking valve is in place or the tracheostomy is capped, aerosolization is less of a consideration and is the equivalent of a patient with a cough and on low-flow oxygen; in such cases, the patients may wear a mask over their nose and mouth. Decannulation (ie, removal of the tracheostomy) is considered an AGP, and provided the patient remains infectious, all the usual airborne precautions should be taken. (See "Infection prevention: Precautions for preventing transmission of infection", section on 'Airborne precautions'.)

Nutrition, physical, occupational, and speech therapy — Patients who require PMV are frequently deconditioned due to prolonged illness and immobility [20]. We ensure that all patients undergo a nutritional, physical, and occupational therapy evaluation by specialists trained in those areas. Speech therapy may be required for those in need of swallowing evaluation or speech training, especially after tracheostomy decannulation.

●Physical and occupational therapy – Many patients undergo physical and occupational therapy during ventilator weaning, which progresses as ventilator dependence improves. It is generally graded, starting with passive range of motion and antigravity limb training at the lowest levels and progressing to sitting in a chair, standing, walking, and performing activities of daily living at the highest levels [21,22].

Limited data in patients with PMV suggest that the physical and psychological benefits of physical therapy that have already been established in a wide range of patient care settings also extend to patients who require PMV. One study randomly assigned 39 patients undergoing PMV to receive six weeks of physical training or no physical therapy [23]. Compared with baseline, patients who received physical therapy improved their respiratory and extremity muscle strength, functional status, and ventilator-free duration. In contrast, the control group did not improve in any of the outcomes measured.

●Nutrition – During critical illness, protein catabolism leads to decreased respiratory muscle mass, strength, and endurance [24]. The purpose of nutrition support is to minimize these effects. Studies in critically ill patients in the ICU suggest that nutrition support may reduce the duration of mechanical ventilation but studies in patients undergoing PMV are lacking [25-28]. The impact of nutritional support in critically ill patients is discussed in detail separately. (See "Nutrition support in critically ill adult patients: Initial evaluation and prescription".)

Nutritional needs and delivery may change over the course of a patient's stay in an LTACH, with most initially receiving enteral nutrition via a feeding tube. Select patients may progress to an oral diet under the close supervision of a speech-language pathologist (SLP) even with mechanical ventilation, provided they are not at risk of aspiration. However, many patients do not progress to an oral diet until after decannulation.

●Speech evaluation – Most patients need SLP evaluation for Passy Muir valve trials once weaned from mechanical ventilation and for voice training once decannulated since phonation is often weak following PMV. (See "Complications of the endotracheal tube following initial placement: Prevention and management in adult intensive care unit patients", section on 'Swallowing and speech impairment'.)

Management of complications — Patients receiving PMV suffer from several types of complications during their course [12,29-31]. Most of these complications and their management are discussed in separate topic reviews:

●Complications of mechanical ventilation. (See "Clinical and physiologic complications of mechanical ventilation: Overview".)

●Medical complications experienced in nursing home patients, in particular infections such as pneumonia [32,33]. (See "Medical care in skilled nursing facilities (SNFs) in the United States" and "Principles of infection prevention and control in long-term care facilities" and "Outbreaks in long-term care facilities: Detection and management".)

●Complications of tracheostomy. (See "Tracheostomy: Postoperative care, maintenance, and complications in adults", section on 'Late (≥7 to 10 days)'.)

●Post-intensive care syndrome (PICS) (physical, psychological, and/or cognitive impairment) and PICS-family [34]. (See "Post-intensive care syndrome (PICS) in adults: Clinical features and diagnostic evaluation".)

Wound care — Meticulous skin care is critical in this population since immobility is typically prolonged. Patients may also be admitted with wounds incurred prior to or during critical illness that may need special attention by a wound care specialist. Further details are provided separately. (See "Medical care in skilled nursing facilities (SNFs) in the United States", section on 'Pressure injury'.)

Venous thromboembolism prophylaxis — We typically place inpatients recovering from critical illness on venous thromboembolism prophylaxis until the acute illness fully resolves and/or the patient becomes fully mobile, although the efficacy of this approach is unknown.

Guidance on duration of therapeutic anticoagulation varies with the indication and is similar to that described for patients not undergoing PMV. (See "Venous thromboembolism: Anticoagulation after initial management".)

Stress ulcer prophylaxis — It is unknown whether stress ulcer prophylaxis (SUP) should be administered in this population. Our practice is to administer SUP in patients who are undergoing ventilator weaning but not those who are chronically ventilated [35].

PROGNOSIS — 

Patient-important outcomes include mortality, ventilator liberation, and discharge to home. Although estimates of mortality and other clinical outcomes vary considerably, overall mortality for patients undergoing PMV is high and even for the survivors, quality of life is often low.

Since family members and caregivers tend to be more optimistic than clinicians about the eventual outcomes [36], it is important that clinicians educate patients and family/caregivers about these potential outcomes regarding the overall goals of care during their admission. (See 'Setting expectations and advance care planning' below.)

The variability in outcome may reflect the heterogeneity in patients studied, ranging from those with a low to high likelihood of successful weaning from mechanical ventilation as well as the range of transfer practices and patient case mix from the transferring intensive care unit (ICU) to the LTACH [37,38].

Mortality and predictors — The mortality in patients undergoing PMV ranges from 24 to 73 percent at one-year [12,39-51]. As examples:

●A meta-analysis of 39 studies of patients on PMV reported a one-year mortality of approximately 60 percent (73 percent in US hospitals and 47 percent in non-US hospitals) [40].

●One observational study of 1419 patients on PMV reported a similar one-year mortality of 52 percent [12]. Among these patients, 25 percent died in the LTACH and 27 percent died after discharge. Patients were excluded from the study if they were admitted for end-of-life care or terminal weaning or were deemed incapable of weaning at the time of admission.

Predictors have been reported [46,48,49,51-56].

●Consistent among studies are the following:

•Age ≥50 years – As an example, in a retrospective study of 308 adults undergoing PMV, in-LTACH mortality was 31 percent for 40 to 59 years, 41 percent for 60 to 79 years, and 55 percent for age ≥80 years [57].

•Multiple comorbidities or predictors – The presence of multiple predictors appears to be cumulative. In one prospective study of patients undergoing PMV, the need for vasopressors or hemodialysis during the ICU admission, the presence of thrombocytopenia, and age ≥50 years were associated with a mortality of 97 percent while the absence of these three factors was associated with 15 percent mortality [53].

●Other factors have been variably reported:

•Admission from or to a skilled-care facility

•Longer hospital length of stay (in the acute care facility)

•Primary diagnosis of sepsis

•Hematologic malignancy

•Male sex

•Need for hemodynamic support including hemodialysis (in the acute care facility)

•Thrombocytopenia

•Poor skin integrity

•Chronic irreversible neurologic diseases

•Cognitive impairment or vegetative or minimally conscious states

•Duration of mechanical ventilation

Ventilator liberation success — Time to and rates and predictors of successful liberation are discussed below:

●Time to successful liberation – Patients requiring PMV spend an average of 36 days mechanically ventilated in the ICU and 31 days weaning outside the ICU [15]. In our experience, most patients require several months to be liberated from mechanical ventilation [39,58].

●Rates of successful liberation – Several studies report rates of successful liberation rates that range from 33 to 60 percent [40,41,50,56,58-60].

In a meta-analysis of 39 studies of patients on PMV, only 50 percent were successfully liberated from mechanical ventilation [40]. Similarly, a retrospective cohort study of 135 patients admitted to an LTACH facility for ventilator liberation reported that 43 percent were successfully liberated and the remaining 58 percent were fully or partly dependent upon mechanical ventilation at one year [58]. Among those who were successfully liberated, 81 percent were decannulated successfully.

In general, the longer the ventilator-free period following liberation, the lower the likelihood of the need for PMV reinstitution [59].

The wide range of liberation rates may be due to variable practice among LTACHs. For example, a prospective payer system that pays the full rate for a specified number of days and then a reduced rate for subsequent stay has forced LTACHs to be more selective in choosing patients with the highest liberation potential [61].

●Predictors of successful liberation – Validated predictors of successful liberation are unknown.

Predictive scores have been published. One study of 372 patients requiring PMV examined the utility of a score based on mechanical ventilator settings calculated after tracheostomy placement to predict ventilator independence [62]. The area under the curve was 0.71 for differentiating patients who were liberated within the first 14 days compared with those who were not liberated during that time period. Further study is needed before this or any other score should be used routinely in patients undergoing PMV.

The rapid shallow breathing index (RSBI) performs poorly in this population and has fallen out of favor [63]. The value of RSBI in the acute ICU population undergoing ventilator liberation is discussed separately. (See "Weaning from mechanical ventilation: Readiness testing", section on 'Rapid shallow breathing index'.)

Discharge home — Discharge to home ranges from 16 to 47 percent [40,64,65]. In a meta-analysis of 39 studies of patients on PMV, only 19 percent were discharged to home (range 16 to 24 percent) [40]. In an observational study of 80 patients requiring PMV (defined in this study as ≥7 days of mechanical ventilation), 47 percent were discharged home and 14 percent remained hospitalized [64]. Three or fewer comorbid conditions and an Acute Physiology Score ≤21 were associated with the best outcomes. In contrast, patients with more comorbid conditions or a slower rate of improvement were least likely to be discharged home within six months.

Quality of life — Survivors of critical illness have a lower quality of life than age- and sex-matched controls [66]. Pre-existing illnesses may contribute [67].

Approximately 76 percent of patients who survive PMV and tracheostomy indicate that they would have chosen mechanical ventilation if they were able to make the decision [68]. However, the responses were influenced by their current health as well as the financial and emotional burden that their illness had on their family and other caregivers.

Physical, cognitive, and psychological outcomes — Survivors of critical illness commonly experience physical, cognitive, and psychological dysfunction. Any one or more of such symptoms constitutes post-intensive care syndrome (PICS). PICS is discussed in detail separately. (See "Post-intensive care syndrome (PICS) in adults: Clinical features and diagnostic evaluation".)

Similar symptoms have been reported in patients undergoing PMV and transferred to LTACH facilities for ventilator weaning [69-71].

●Psychological – In a prospective cohort study of 336 patients transferred to an LTACH facility for PMV, 42 percent were diagnosed with depressive disorders [70]. These patients were at higher risk for liberation failure and mortality. In a similar study with 41 patients, 12 percent were diagnosed with post-traumatic stress disorder within three months following weaning [71]. In a study of 74 patients who required PMV (mean duration of ventilation 28 days), 25 percent of patients reported moderate to severe depression and anxiety two years after discharge [69].

●Cognitive – In a study of 74 patients who required PMV, cognitive sequelae were detected in 77 percent of survivors at discharge and 47 percent of survivors two years later [69].

●Physical – Many patients who undergo PMV suffer from significant physical dysfunction requiring lengthy rehabilitation. In a study of 203 people with chronic critical illness, among the quarter that survived and discharged, 62 percent were dependent in all activities of daily living [72].

Hospital readmission — Rehospitalization for intercurrent illnesses is common in patients who undergo PMV (20 to 67 percent) [49,73,74].

Intercurrent illnesses range from minor issues, such as a urinary tract infection that can be treated in the LTACH, to severe life-threatening illness that requires readmission to an acute care ICU (eg, septic shock) [49,73]. In one retrospective study, patients who underwent PMV were more likely to be readmitted to hospital at one year compared with patients who received mechanical ventilation in an ICU but did not undergo PMV (47 versus 38 percent) [73].

The wide range of rehospitalization rates may be due to variable practice among LTACHs. Some LTACHs have on-location ICUs that readily accept severely ill patients, possibly resulting in a higher threshold for transfer [61].

COVID-19 — Data in patients with coronavirus disease 2019 (COVID-19) who needed a tracheostomy for respiratory failure and underwent ventilator liberation suggest that the outcomes may be better than in patients undergoing PMV who did not have COVID-19. However, much of these data were derived in patients who were ill in the initial phases of the pandemic and may not reflect outcomes in the later phase when critical illness due to COVID-19 had waned.

●One retrospective study of 158 COVID-19 patients who required tracheostomy for PMV reported successful liberation in 71 percent and a mortality of 10 percent [75]. Liberation duration was only eight days. By the end of the study period, 19 percent were discharged home while 70 percent were discharged to other facilities (eg, rehabilitation facilities [46 percent], acute care hospitals [17 percent], or nursing facilities [7 percent]).

●In another retrospective study of patients who underwent tracheostomy for COVID-19, 90 percent were alive 90 days later, 2.7 percent still had a tracheostomy, 33 percent still had a feeding tube, and almost two-thirds were at home [76].

●Another retrospective analysis also reported that liberation rates may be higher in patients with COVID-19 compared with non-COVID-19 illnesses (91 versus 56 percent) [77].

These rates are markedly different from reported rates in the non-COVID population. These data are discussed above. (See 'Mortality and predictors' above and 'Ventilator liberation success' above.)

SETTING EXPECTATIONS AND ADVANCE CARE PLANNING — 

We have early, frank discussions regarding the outcomes in patients who undergo PMV so that realistic expectations can be set [78,79]. This generally involves discussion with the patient, if feasible, and their surrogates. Social workers and case managers are intricately involved in these discussions especially when discharge planning is needed.

We also consult palliative care services to evaluate goals of care on an ongoing basis. This allows for a smooth transition to palliative care when patients, for example, fail liberation trials and ventilator-dependence is not in keeping with their long-term goals. Further details regarding family/caregiver meetings and advance care planning are provided separately. (See "Communication in the ICU: Holding a meeting with families and caregivers of adult patients" and "Palliative care: Issues in the intensive care unit in adults" and "Withholding and withdrawing ventilatory support in adults in the intensive care unit" and "Advance care planning and advance directives".)

RESOURCE UTILIZATION — 

There is a growing body of literature examining the costs of caring for patients who require PMV. One cost-effectiveness analysis found that providing PMV costs $55,460 per life-year gained and $82,411 per quality-adjusted life-year gained compared with withdrawal of ventilation [80]. The incremental costs per quality-adjusted life-year gained exceeded $100,000 among those patients who were ≥68 years old or whose predicted one-year mortality was >50 percent. (See "A short primer on cost-effectiveness analysis".)

Much of this cost is probably related to the cost of ongoing medical care from both the LTACH facility and acute care hospital readmission(s). In one study, the mean cost per patient exceeded $300,000 by one year [74].

SUMMARY AND RECOMMENDATIONS

●Definition – Prolonged mechanical ventilation (PMV) is defined as >21 days of mechanical ventilation for at least six hours per day, although many studies have used alternative durations to define PMV. Between 4 and 13 percent of mechanically ventilated patients require PMV. These patients usually reside in long-term acute care hospitals. (See 'Introduction' above and 'Definition' above and 'Epidemiology' above.)

●Initial evaluation – Upon admission, we obtain a comprehensive history of the patient's acute critical illness and perform a thorough examination. This includes the following (see 'Initial evaluation' above):

•Intensive care unit (ICU) illness timeline.

•Reason for and duration of ICU admission.

•Complications during ICU admission.

•Administered treatments.

•Issues that need follow-up.

•Tracheostomy details.

•Ventilator settings.

•History of spontaneous breathing trials (SBTs).

•Pre-existing illnesses.

•Medication reconciliation.

•Current symptoms and signs.

•Routine examination including skin, tracheostomy, and neurologic and musculoskeletal assessment.

•Routine laboratory studies, arterial blood gas, and liver function and coagulation studies as well as chest radiograph, electrocardiography, and urine analysis. Additional laboratory and imaging tests are appropriate for select patients.

●Management – Management largely focuses on optimizing underlying illnesses (eg, pulmonary conditions), mechanical ventilation liberation, rehabilitation (encompassing physical, nutritional, occupational, and speech-related issues), and management of complications that arise periodically in this population (eg, urinary tract and pulmonary infections, tracheostomy complications).

●Ventilator liberation – The optimal protocol for ventilator liberation in patients who require PMV is unknown.

•Ventilator liberation can be initiated when the criteria listed in the table are met (table 2). (See 'Patient selection' above.)

•For most patients with PMV, we suggest slow-paced, once-daily weaning with a gradual lengthening of SBTs rather than a gradual continuous reduction in ventilatory support (Grade 2C). This strategy is based upon our experience and successful use in the acute ICU population. (See 'Ventilator liberation strategies' above and "Initial weaning strategy in mechanically ventilated adults", section on 'Daily spontaneous breathing trials (SBTs)'.)

•SBTs may be performed either using low-level pressure support (PSV-SBT; eg, 5 to 8 cm H₂O) or tracheostomy collar. The choice depends on the patient's ability to tolerate each type of SBT and institutional practice. The advantage of PSV-SBT is closer monitoring of tidal volumes and respiratory rate, which may be more appropriate for patients who have altered mental status or have not tolerated prior SBTs. Tracheostomy collars are often more comfortable and affirming for patients (since they are temporarily liberated from the ventilator); tracheostomy collar SBTs may reduce time to complete ventilator liberation. (See 'Ventilator liberation method' above and "Initial weaning strategy in mechanically ventilated adults", section on 'Choosing ventilatory support'.)

•Once the patient can tolerate 24 hours of a tracheostomy collar, we consider preparing for tracheostomy decannulation. The procedure for decannulation is provided separately. (See "Tracheostomy: Postoperative care, maintenance, and complications in adults", section on 'Decannulation'.)

•For patients who fail an SBT at any point, we resume their prior ventilation settings and address any potential reasons for failure before reinitiating SBTs.

●Prognosis – The prognosis of patients who undergo PMV is poor. We have early, frank discussions regarding the outcomes so that realistic expectations can be set. (See 'Prognosis' above.)

•Mortality for patients undergoing PMV is high (33 to 77 percent) and even for the survivors, quality of life is often low. Only a small proportion return to independent living with satisfactory function. Patients commonly experience physical, cognitive, and psychological dysfunction. Increasing age is a consistent predictor of mortality as is multiple comorbidities. (See 'Mortality and predictors' above.)

•Rates of successful liberation range from 35 to 60 percent. Patients are considered permanently ventilator-dependent when three months of weaning attempts have failed. (See 'Ventilator liberation success' above.)

•Discharge to home ranges from 16 to 47 percent. (See 'Discharge home' above.)

ACKNOWLEDGMENT — 

The UpToDate editorial staff acknowledges Melissa Miller, MD, who contributed to earlier versions of this topic review.