Specific inspiratory muscle training is safe in selected patients who are ventilator-dependent: a case series

Feasibility, safety, and patient acceptability of electronic inspiratory muscle training in patients who require prolonged mechanical ventilation in the intensive care unit: A dual-centre observational study

BACKGROUND

Inspiratory muscle training (IMT) is an intervention that can be used to rehabilitate the respiratory muscle deconditioning experienced by patients with critical illness, requiring prolonged mechanical ventilation. Clinicians are currently using mechanical threshold IMT devices that have limited resistance ranges.

OBJECTIVES

The objective of this study was to evaluate the safety, feasibility, and acceptability of using an electronic device to facilitate IMT with participants requiring prolonged mechanical ventilation.

METHOD

A dual-centre observational cohort study, with convenience sampling, was conducted at two tertiary intensive care units. Daily training supervised by intensive care unit physiotherapists was completed with the electronic IMT device. A priori definitions for feasibility, safety, and acceptability were determined. Feasibility was defined as more than 80% of planned sessions completed. Safety was defined as no major adverse events and less than 3% minor adverse event rate, and acceptability was evaluated following the acceptability of intervention framework principles.

RESULTS

Forty participants completed 197 electronic IMT treatment sessions. Electronic IMT was feasible, with 81% of planned sessions completed. There were 10% minor adverse events and no major adverse events. All the minor adverse events were transient without clinical consequences. All the participants who recalled completing electronic IMT sessions reported that the training was acceptable. Acceptability was demonstrated; over 85% of participants reported that electronic IMT was either helpful or beneficial and that electronic IMT assisted their recovery.

CONCLUSION

Electronic IMT is feasible and acceptable to complete with critically ill participants who require prolonged mechanical ventilation. As all minor adverse events were transient without clinical consequences, electronic IMT can be considered a relatively safe intervention with patients who require prolonged mechanical ventilation.

The effect of threshold inspiratory muscle training on the duration of weaning in intensive care unit-admitted patients: A randomized clinical trial

Background

The purpose of this study was to evaluate the effect of threshold inspiratory muscle training (IMT) on the duration of weaning in intensive care unit (ICU)-admitted patients.

Materials and Methods

This randomized clinical trial enrolled 79 ICU-admitted, mechanically ventilated patients in 2020-2021 in Imam Reza Hospital, Mashhad. Patients were randomly divided into intervention (n = 40) and control (n = 39) groups. The intervention group received threshold IMT and conventional chest physiotherapy, while the control group only received conventional chest physiotherapy once a day. Before and after the end of the intervention, the strength of inspiratory muscles and the duration of weaning were measured in both the groups.

Results

The duration of weaning was shorter in the intervention group (8.4 ± 1.1 days) versus the control group (11.2 ± 0.6 days) (P < 0.001). The rapid shallow breathing index decreased by 46.5% in the intervention group and by 27.3% in the control group after the intervention (both P < 0.001), and the between-group comparison showed a significantly higher reduction in the intervention group than control group (P < 0.001). The patients' compliance after the intervention compared to the 1^st day increased to 16.2 ± 6.6 in the intervention group and 9.6 ± 6.8 in the control group (both P < 0.001), and the between-group comparison showed a significantly higher increase in the intervention group than control group. The maximum inspiratory pressure increased by 13.7 ± 6.1 in the intervention group and by 9.1 ± 6.0 in the control group (P < 0.001). Furthermore, the weaning success was 54% more probable in the intervention group than control group (P < 0.05).

Conclusion

The results of this study showed the positive effect of IMT with threshold IMT trainer on increased strength of respiratory muscles and reduced weaning duration.

Does mechanical threshold inspiratory muscle training promote recovery and improve outcomes in patients who are ventilator-dependent in the intensive care unit? The IMPROVE randomised trial

BACKGROUND

In patients who are ventilator-dependent in the intensive care unit, inspiratory muscle training may improve inspiratory muscle strength and accelerate liberation from the ventilator, but optimal training parameters are yet to be established, and little is known about the impact of inspiratory muscle training on quality of life or dyspnoea. Thus, we sought to ascertain whether inspiratory muscle training, commenced while ventilator-dependent, would improve outcomes for patients invasively ventilated for 7 days or longer.

METHODS

In this randomised trial with assessor blinding and intention-to-treat analysis, 70 participants (mechanically ventilated ≥7 days) were randomised to receive once-daily supervised high-intensity inspiratory muscle training with a mechanical threshold device in addition to usual care or to receive usual care (control). Primary outcomes were inspiratory muscle strength (maximum inspiratory pressure % predicted) and endurance (fatigue resistance index) at ventilator liberation and 1 week later. Secondary outcomes included quality of life (SF-36v2, EQ-5D), dyspnoea, physical function, duration of ventilation, and in-hospital mortality.

RESULTS

Thirty-three participants were randomly allocated to the training group, and 37 to the control group. There were no statistically significant differences in strength (maximum inspiratory pressure) (95% confidence interval [CI]: -7.4 to 14.0) or endurance (fatigue resistance index) (95% CI: -0.003 to 0.436). Quality of life improved significantly more in the training group than in the control group (EQ-5D: 17.2; 95% CI: 1.3-33.0) (SF-36-PCS: 6.97; 95% CI: 1.96-12.00). Only the training group demonstrated significant reductions in dyspnoea (-1.5 at rest, -1.9 during exercise). There were no between-group differences in duration of ventilation or other measures. In-hospital mortality was higher in the control group than in the training group (9 vs 4, 24% vs 12%, p = 0.23).

CONCLUSIONS

In patients who are ventilator-dependent, mechanical threshold loading inspiratory muscle training improves quality of life and dyspnoea, even in the absence of strength improvements or acceleration of ventilator liberation.

Inspiratory muscle training in intensive care unit patients: An international cross-sectional survey of physiotherapist practice

BACKGROUND

Inspiratory muscle training is safe and effective in reversing inspiratory muscle weakness and improving outcomes in patients who have experienced prolonged mechanical ventilation in the intensive care unit (ICU). The degree of worldwide implementation of inspiratory muscle training in such patients has not been investigated.

OBJECTIVES

The objectives of this study were to describe the current practice of inspiratory muscle training by intensive care physiotherapists and investigate barriers to implementation in the intensive care context and additionally to determine if any factors are associated with the use of inspiratory muscle training in patients in the ICU and identify preferred methods of future education.

METHOD

Online cross-sectional surveys of intensive care physiotherapists were conducted using voluntary sampling. Multivariate logistic regression analysis was used to identify factors associated with inspiratory muscle training use in patients in the ICU.

RESULTS

Of 360 participants, 63% (95% confidence interval [CI] = 58 to 68) reported using inspiratory muscle training in patients in the ICU, with 69% (95% CI = 63 to 75) using a threshold device. Only 64% (95% CI = 58 to 70) of participants who used inspiratory muscle training routinely assessed inspiratory muscle strength. The most common barriers to implementing inspiratory muscle training sessions in eligible patients were sedation and delirium. Participants were 4.8 times more likely to use inspiratory muscle training in patients if they did not consider equipment a barrier and were 4.1 times more likely to use inspiratory muscle training if they aware of the evidence for this training in these patients. For education about inspiratory muscle training, 41% of participants preferred online training modules.

CONCLUSION

In this first study to describe international practice by intensive care therapists, 63% reported using inspiratory muscle training. Improving access to equipment and enhancing knowledge of inspiratory muscle training techniques could improve the translation of evidence into practice.

Effect of external diaphragmatic pacing therapy on patients with chronic cor pulmonale: a randomized, controlled trial

Objectives

This study aimed to evaluate the effects of external diaphragmatic pacing (EDP) on patients with chronic cor pulmonale (CCP).

Methods

Fifty patients with CCP were enrolled in Kashgar Prefecture Second People’s Hospital in Xinjiang Uygur Autonomous Region of China from 2016 to 2017. The patients were randomized into a group that received anti-CCP therapy (negative control group) or a group that received additional EDP treatment (EDP group). We recorded and compared maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, and the 6-minute walking test between the two groups on the first and tenth days of treatment.

Results

Ten days after treatment began, MIP, FVC, and the 6-minute walking test were significantly improved in both groups. Importantly, MIP and FVC were significantly higher in the EDP group compared with the control group on the tenth day.

Conclusion

In addition to treatment for CCP, these patients can obtain extra benefit by using EDP treatment.

Analogy between classical Yoga/Zen breathing and modern clinical respiratory therapy

Anesthesiologists and intensivists are modern-day professionals who provide appropriate respiratory care, vital for patient survival. Recently, anesthesiologists have increasingly focused their attention on the type of spontaneous breathing made by non-intubated patients with pulmonary disease cared for in an intensive care unit, and also patients with chronic pain receiving cognitive behavioral therapy. Prior to our modern understanding of respiratory physiology, Zen meditators recognized that breathing has a significant impact on a person’s mental state and general physical well-being. Examples of this knowledge regarding respiration include the beneficial effects of deep inhalation and slow exhalation on anxiety and general wellness. The classical literature has noted many suggestions for breathing and its psycho-physical effects. In the present review, we examine the effect of classical breathing methods and find an analogy between typical Yoga/Zen breathing and modern clinical respiratory therapy. Evidence is increasing about historical breathing and related meditation techniques that may be effective in modern clinical practice, especially in the field of anesthesiology, such as in improving respiratory function and reducing chronic pain. Clarification of the detailed mechanisms involved is anticipated.

Cambios fisiológicos relacionados con entrenamiento muscular respiratorio en pacientes con ventilación mecánica

Introducción. El entrenamiento muscular respiratorio es una técnica fisioterapéutica usada para incrementar la fuerza de la musculatura respiratoria, sin embargo pocos estudios han abordado los cambios fisiológicos relacionados con esta intervención en pacientes con ventilación mecánica.Objetivo. Determinar los cambios fisiológicos relacionados con el entrenamiento muscular respiratorio en pacientes con ventilación mecánica.Materiales y métodos. Se realizó un análisis de datos secundarios en el marco del estudio “Eficacia del entrenamiento muscular respiratorio en el destete de la ventilación mecánica en pacientes con ventilación mecánica por 48 horas o más: Un ensayo clínico controlado”. La población estuvo conformada por los 62 pacientes del grupo experimental del estudio principal, quienes recibieron entrenamiento muscular respiratorio. Los valores de frecuencia cardiaca, frecuencia respiratoria, presión arterial, saturación de oxígeno y volumen corriente fueron registrados. La diferencia entre el promedio de cada una de las variables fue analizada mediante la prueba de t pareada, mientras que para el análisis de los cambios fisiológicos entre sesiones de entrenamiento se empleó la prueba de Kruskal-Wallis.Resultados. Se observaron diferencias significativas entre las variables fisiológicas antes y después del entrenamiento muscular respiratorio (p<0.05), a excepción del volumen corriente y la presión arterial media (p>0.05). Por el contrario, no se observaron diferencias significativas en ninguna de las variables fisiológicas entre sesiones de entrenamiento (p>0.05)Conclusiones. El entrenamiento muscular respiratorio es una intervención terapéutica viable y tolerable en esta población.

Respiratory Muscle Rehabilitation in Patients with Prolonged Mechanical Ventilation: A Targeted Approach

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2020. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Inspiratory muscle training is feasible and safe for patients with acute spinal cord injury

OBJECTIVE

To investigate the feasibility and safety and, to a lesser extent efficacy, of inspiratory muscle training (IMT) for patients with acute complete cervical or thoracic spinal cord injury (SCI).

DESIGN

Prospective, observational pilot study comprising a series of case reports.

SETTING

Tertiary care, public hospital.

PARTICIPANTS

Seven adult subjects with an acute complete cervical or thoracic SCI.

INTERVENTIONS

Participants received IMT as soon as their respiratory condition was stable. A high-resistance, low-repetition program of IMT using a POWERbreathe KH1 device was instituted. Training comprised 3-6 sets of 6 breaths, commenced at 50% maximum inspiratory pressure with the training load progressively increased.

OUTCOME MEASURES

Feasibility (number of sessions when the criteria to participate in IMT were met/not met), safety (symptoms and physiological stability) before, during and after IMT sessions and efficacy (lung function) were measured.

RESULTS

There were 50 sessions in total where participants met the criteria to receive IMT, with a mean (range) of 7.1 (3-11) IMT sessions per participant delivered over 10.7 (4-17) days. IMT was feasible, with all 50 planned sessions of IMT able to be delivered, and safe, with stable physiological parameters and no adverse symptoms or events recorded before, during or after IMT. Maximal inspiratory pressure increased for four participants and forced vital capacity increased for three participants over the duration of their IMT sessions.

CONCLUSION

A high-resistance, low-repetition program of IMT was feasible and safe in adults with an acute complete cervical or thoracic SCI whose respiratory status was stable.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN 12614000975695).

Which ICU patients benefit most from inspiratory muscle training? Retrospective analysis of a randomized trial

Background: Inspiratory muscle training (IMT) increases inspiratory muscle strength and improves quality of life in intensive care unit (ICU) patients who have been invasively mechanically ventilated for ≥7 days. The purpose of this study was to identify which patients benefit most from IMT following weaning from mechanical ventilation. Methods: Secondary analysis of a randomized trial of supervised daily IMT in 70 patients (mean age 59 years) in a 31-bed ICU was carried out. Changes in inspiratory muscle strength (maximum inspiratory pressure, MIP) between enrolment and 2 weeks (ΔMIP) were analyzed to compare the IMT group (71% male) and the control group (58% male). Linear regression models explored which factors at baseline were associated with ΔMIP. Results: Thirty-four participants were allocated to the IMT group where baseline MIP was associated with an increase in ΔMIP, significantly different from the control group (p = 0.025). The highest ΔMIP was associated with baseline MIP ≥ 28 cmH₂O. In the IMT group, higher baseline quality of life (EQ5D) scores were associated with positive ΔMIP, significantly different from the control group (p = 0.029), with largest ΔMIP for those with EQ5D ≥ 40. Conclusions: Physiotherapists should target ICU patients with moderate inspiratory muscle weakness (MIP ≥28 cmH₂O) and moderate to high quality of life (EQ5D>40) within 48 h of ventilatory weaning as ideal candidates for IMT following prolonged mechanical ventilation.

[The personalized approach to the rehabilitation of a severely ill patient presenting with a cardio-surgical problem]

The ever increasing number of the patients presenting with the cardio-surgical problems referred for surgery emphasizes the importance of the treatment of the cases of post-operative complications based on the personalized approach. The present article was designed to report a clinical case of the successful surgical treatment and rehabilitation of a patient presenting with the dysfunction of the bioprosthetic mitral valve and complications of the post-operative course in the form of polyorgan insufficiency with the predominance of respiratory failure. Special attention is given to the post-operative complications among which the respiratory insufficiency prevailed that made necessary the long period of artificial pulmonary ventilation. The specific features of the intense personalized approach to the physical rehabilitation of the given severely ill patient based at the intensive care unit are considered, the description of the methods applied for the purpose is presented, and their effectiveness from the perspective of clinical and functional parameters is evaluated. The study has demonstrated that the application of the intensive personalized approach in the given case turned out to be a safe and effective method of rehabilitation. The use of the proposed approach allowed to shorten the duration of the post-operative rehabilitation period, facilitated the patient's transfer to autonomous breathing and expansion of the motor activity under conditions of the intensive care unit. In addition, the use of the continuity principle and continuation of rehabilitation measures based at the cardiac surgery department provided the opportunity for the further expansion of the motor activity.

Inspiratory muscle training for intensive care patients: A multidisciplinary practical guide for clinicians

OBJECTIVES

To describe a multidisciplinary approach to inspiratory muscle training (IMT) for patients in the intensive care unit (ICU).

BACKGROUND

Inspiratory muscle weakness is a known consequence of prolonged mechanical ventilation, and there is emerging evidence that specific IMT can ameliorate this weakness. However, IMT is not yet standard practice in many ICUs, possibly because of the wide variety of methods reported and a lack of published practical guidelines. While the optimal parameters for IMT are yet to be established, we share our detailed methodology which has been shown to be safe in selected ventilator-dependent patients and is the only approach which has been shown to increase quality of life in ICU patients.

METHODS

Patients who have experienced invasive mechanical ventilation for at least 7 days can commence IMT in either the ventilator-dependent phase or when weaned from mechanical ventilation. Intensity should be prescribed based on maximum inspiratory pressure, which is measurable through the tracheostomy or endotracheal tube via the ventilator or a respiratory pressure meter. Using a removable threshold device, we recommend high-intensity training (5 sets of 6 breaths at a minimum of 50% of maximum inspiratory pressure) performed once per day, supervised by the physiotherapist, with intensity increased daily such that patients can only just complete the 6th breath in each set.

RESULTS

Using this high-intensity approach, IMT is likely to improve not only inspiratory muscle strength but also quality of life in patients recently weaned from mechanical ventilation of 7 days' duration or longer. Effective IMT requires a multidisciplinary approach to maximise feasibility, with doctors, nurses, and therapists working closely to optimise conditions for successful IMT.

CONCLUSIONS

This multidisciplinary approach to implement IMT in ICU patients should assist clinicians in translating best-available evidence into practice, with the potential to enhance patient recovery.

Efficacy of respiratory muscle training in weaning of mechanical ventilation in patients with mechanical ventilation for 48hours or more: A Randomized Controlled Clinical Trial

OBJECTIVE

To evaluate the efficacy of respiratory muscular training in the weaning of mechanical ventilation and respiratory muscle strength in patients on mechanical ventilation of 48hours or more.

DESIGN

Randomized controlled trial of parallel groups, double-blind. Ambit: Intensive Care Unit of a IV level clinic in the city of Cali.

PATIENTS

126 patients in mechanical ventilation for 48hours or more.

INTERVENTIONS

The experimental group received daily a respiratory muscle training program with treshold, adjusted to 50% of maximal inspiratory pressure, additional to standard care, conventional received standard care of respiratory physiotherapy. MAIN INTEREST VARIABLES: weaning of mechanical ventilation. Other variables evaluated: respiratory muscle strength, requirement of non-invasive mechanical ventilation and frequency of reintubation.

ANALYSIS

intention-to-treat analysis was performed with all variables evaluated and analysis stratified by sepsis condition.

RESULTS

There were no statistically significant differences in the median weaning time of the MV between the groups or in the probability of extubation between groups (HR: 0.82 95% CI: 0.55-1.20 P=.29). The maximum inspiratory pressure was increased in the experimental group on average 9.43 (17.48) cmsH20 and in the conventional 5.92 (11.90) cmsH20 (P=.48). The difference between the means of change in maximal inspiratory pressure was 0.46 (P=.83 95%CI -3.85 to -4.78).

CONCLUSIONS

respiratory muscle training did not demonstrate efficacy in the reduction of the weaning period of mechanical ventilation nor in the increase of respiratory muscle strength in the study population. Registered study at ClinicalTrials.gov (NCT02469064).

Inspiratory Muscle Training in the Intensive Care Unit: A New Perspective

Background

Prolonged use of mechanical ventilation (MV) leads to weakening of the respiratory muscles, especially in patients subjected to sedation, but this effect seems to be preventable or more quickly reversible using respiratory muscle training. The aims of the study were to assess variations in respiratory and hemodinamic parameters with electronic inspiratory muscle training (EIMT) in tracheostomized patients requiring MV and to compare these variations with those in a group of patients subjected to an intermittent nebulization program (INP).

Methods

This was a pilot, prospective, randomized study of tracheostomized patients requiring MV in one intensive care unit (ICU). Twenty-one patients were randomized: 11 into the INP group and 10 into the EIMT group. Two patients were excluded in experimental group because of hemodynamic instability.

Results

In the EIMT group, maximal inspiratory pressure (MIP) after training was significantly higher than that before (P = 0.017), there were no hemodynamic changes, and the total weaning time was shorter than in the INP group (P = 0.0192).

Conclusion

The EIMT device is safe, promotes an increase in MIP, and leads to a shorter ventilator weaning time than that seen in patients treated using INP.

Inspiratory muscle training to enhance recovery from mechanical ventilation: a randomised trial

Background

In patients who have been mechanically ventilated, inspiratory muscles remain weak and fatigable following ventilatory weaning, which may contribute to dyspnoea and limited functional recovery. Inspiratory muscle training may improve inspiratory muscle strength and endurance following weaning, potentially improving dyspnoea and quality of life in this patient group.

Methods

We conducted a randomised trial with assessor-blinding and intention-to-treat analysis. Following 48 hours of successful weaning, 70 participants (mechanically ventilated ≥7 days) were randomised to receive inspiratory muscle training once daily 5 days/week for 2 weeks in addition to usual care, or usual care (control). Primary endpoints were inspiratory muscle strength and fatigue resistance index (FRI) 2 weeks following enrolment. Secondary endpoints included dyspnoea, physical function and quality of life, post-intensive care length of stay and in-hospital mortality.

Results

34 participants were randomly allocated to the training group and 36 to control. The training group demonstrated greater improvements in inspiratory strength (training: 17%, control: 6%, mean difference: 11%, p=0.02). There were no statistically significant differences in FRI (0.03 vs 0.02, p=0.81), physical function (0.25 vs 0.25, p=0.97) or dyspnoea (−0.5 vs 0.2, p=0.22). Improvement in quality of life was greater in the training group (14% vs 2%, mean difference 12%, p=0.03). In-hospital mortality was higher in the training group (4 vs 0, 12% vs 0%, p=0.051).

Conclusions

Inspiratory muscle training following successful weaning increases inspiratory muscle strength and quality of life, but we cannot confidently rule out an associated increased risk of in-hospital mortality.

Trial registration number

ACTRN12610001089022, results.

Influence of inspiratory muscle training on weaning patients from mechanical ventilation: a systematic review

Abstract Introduction: The inability of respiratory muscles to generate force and endurance is recognized as an important cause of failure in weaning patients from invasive mechanical ventilation (IMV). Thus, inspiratory muscle training (IMT) might be an interesting treatment option for patients with prolonged IMV weaning. Objective: The aim of this systematic literature review was to evaluate the effectiveness of inspiratory muscle training in weaning patients from mechanical ventilation and to identify the most effective type of training for this particular purpose. Methods: We searched PubMed, LILACS, PEDro and Web of Science for randomized clinical trials published in English or Portuguese from January 1990 until March 2015. Results: Eighty-nine studies were identified of which five were selected. A total of 267 patients participated in the five randomized clinical trials analyzed here. IMV duration before onset of training varied greatly among subjects. Three studies performed IMT using a threshold device and two studies used adjustments of ventilator pressure sensitivity. Four studies have shown that IMT resulted in a significant increase in inspiratory maximal pressure. Only two studies, however, have reported that IMT resulted in higher success rates in weaning patients from IMV. One study has found that patients showed a shorter ventilator weaning duration after IMT. Conclusion: IMT using pressure threshold devices results in increased inspiratory muscle strength and can therefore be considered a more effective treatment option and with the potential to optimize ventilator weaning success in patients at risk of prolonged IMV.

Inspiratory muscle training facilitates weaning from mechanical ventilation among patients in the intensive care unit: a systematic review

QUESTION

Does inspiratory muscle training improve inspiratory muscle strength in adults receiving mechanical ventilation? Does it improve the duration or success of weaning? Does it affect length of stay, reintubation, tracheostomy, survival, or the need for post-extubation non-invasive ventilation? Is it tolerable and does it cause adverse events?

DESIGN

Systematic review of randomised trials.

PARTICIPANTS

Adults receiving mechanical ventilation.

INTERVENTION

Inspiratory muscle training versus sham or no inspiratory muscle training.

OUTCOME MEASURES

Data were extracted regarding: inspiratory muscle strength and endurance; the rapid shallow breathing index; weaning success and duration; duration of mechanical ventilation; reintubation; tracheostomy; length of stay; use of non-invasive ventilation after extubation; survival; readmission; tolerability and adverse events.

RESULTS

Ten studies involving 394 participants were included. Heterogeneity within some meta-analyses was high. Random-effects meta-analyses showed that the training significantly improved maximal inspiratory pressure (MD 7 cmH2O, 95% CI 5 to 9), the rapid shallow breathing index (MD 15 breaths/min/l, 95% CI 8 to 23) and weaning success (RR 1.34, 95% CI 1.02 to 1.76). Although only assessed in individual studies, significant benefits were also reported for the time spent on non-invasive ventilation after weaning (MD 16 hours, 95% CI 13 to 18), length of stay in the intensive care unit (MD 4.5 days, 95% CI 3.6 to 5.4) and length of stay in hospital (MD 4.4 days, 95% CI 3.4 to 5.5). Weaning duration decreased in the subgroup of patients with known weaning difficulty. The other outcomes weren't significantly affected or weren't measured.

CONCLUSION

Inspiratory muscle training for selected patients in the intensive care unit facilitates weaning, with potential reductions in length of stay and the duration of non-invasive ventilatory support after extubation. The heterogeneity among the results suggests that the effects of inspiratory muscle training may vary; this perhaps depends on factors such as the components of usual care or the patient's characteristics.

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.

Mechanical ventilation, diaphragm weakness and weaning: a rehabilitation perspective

Most patients are easily liberated from mechanical ventilation (MV) following resolution of respiratory failure and a successful trial of spontaneous breathing, but about 25% of patients experience difficult weaning. MV use leads to cellular changes and weakness, which has been linked to weaning difficulties and has been labeled ventilator induced diaphragm dysfunction (VIDD). Aggravating factors in human studies with prolonged weaning include malnutrition, chronic electrolyte abnormalities, hyperglycemia, excessive resistive and elastic loads, corticosteroids, muscle relaxant exposure, sepsis and compromised cardiac function. Numerous animal studies have investigated the effects of MV on diaphragm function. Virtually all these studies have concluded that MV use rapidly leads to VIDD and have identified cellular and molecular mechanisms of VIDD. Molecular and functional studies on the effects of MV on the human diaphragm have largely confirmed the animal results and identified potential treatment strategies. Only recently potential VIDD treatments have been tested in humans, including pharmacologic interventions and diaphragm "training". A limited number of human studies have found that specific diaphragm training can increase respiratory muscle strength in FTW patients and facilitate weaning, but larger, multicenter trials are needed.

ICU-based rehabilitation and its appropriate metrics

PURPOSE OF REVIEW

Survival of critically ill patients is frequently associated with significant functional impairment and reduced health-related quality of life. Early rehabilitation of ICU patients has recently been identified as an important focus for interdisciplinary ICU teams. However, the amount of rehabilitation performed in ICUs is often inadequate. The scope of the review is to discuss recent developments in application of assessment tools and rehabilitation in critically ill patients within an interdisciplinary approach.

RECENT FINDINGS

ICU-based rehabilitation has become an important evidence-based component in the management of patients with critical illness. The assessment and evidence-based treatment of these patients should include a focus on prevention and treatment of deconditioning (muscle weakness, joint stiffness, impaired functional performance) and weaning failure (respiratory muscle weakness) to identify targets for rehabilitation. A variety of modalities for assessment and early ICU rehabilitation are supported by emerging clinical research and must be implemented according to the stage of critical illness, comorbidities, and consciousness and cooperation of the patient.

SUMMARY

Daily evaluation of every critically ill patient should include evaluation of the need for bedrest and immobility, and assessment of the potential for early rehabilitation interventions. Early ICU rehabilitation is an interdisciplinary team responsibility, involving physical therapists, occupational therapists, nurses and medical staff.

Respiratory Dysfunction in Ventilated Patients: Can Inspiratory Muscle Training Help?

Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. Moreover, psychological influences, including anxiety, may contribute to difficulty in weaning. There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.

Protocol: inspiratory muscle training for promoting recovery and outcomes in ventilated patients (IMPROVe): a randomised controlled trial

INTRODUCTION

Inspiratory muscle weakness is a known consequence of mechanical ventilation and a potential contributor to difficulty in weaning from ventilatory support. Inspiratory muscle training (IMT) reduces the weaning period and increases the likelihood of successful weaning in some patients. However, it is not known how this training affects the residual inspiratory muscle fatigability following successful weaning nor patients' quality of life or functional outcomes.

METHODS AND ANALYSIS

This dual centre study includes two concurrent randomised controlled trials of IMT in adult patients who are either currently ventilator-dependent (>7 days) (n=70) or have been recently weaned from mechanical ventilation (>7 days) in the past week (n=70). Subjects will be stable, alert and able to actively participate and provide consent. There will be concealed allocation to either treatment (IMT) or usual physiotherapy (including deep breathing exercises without a resistance device). Primary outcomes are inspiratory muscle fatigue resistance and maximum inspiratory pressures. Secondary outcomes are quality of life (Short Form-36v2, EQ-5D), functional status (Acute Care Index of Function), rate of perceived exertion (Borg Scale), intensive care length of stay (days), post intensive care length of stay (days), rate of reintubation (%) and duration of ventilation (days).

ETHICS AND DISSEMINATION

Ethics approval has been obtained from relevant institutions, and results will be published with a view to influencing physiotherapy practice in the management of long-term ventilator-dependent patients to accelerate weaning and optimise rehabilitation outcomes.

TRIAL REGISTRATION NUMBER

ACTRN12610001089022.