Understanding the Management of Patients Undergoing Prolonged Weaning from Mechanical Ventilation: Perspectives from a Speech-Language Pathologist and a Respiratory Physician
Rinki Varindani Desai, MS, CCC-SLP, CBIS, CDP, Speech-Language Pathologist, HealthPRO Heritage, Dallas, Texas, USA
Biswajit Chakrabarti, MD, FRCP, Pulmonologist, University Hospital Aintree, Liverpool, United Kingdom
Patients presenting with respiratory failure are now surviving with the help of medical advances, including tracheostomy tubes and mechanical ventilation. The care of patients on mechanical ventilation has changed significantly over recent decades. Since the 1950s, there has been a shift from devices delivering negative-pressure mechanical ventilation to invasive positive pressure ventilation modes. Frequently, ventilation is delivered via tracheostomy tubes and permits prolonged mechanical respiratory support for most individuals with respiratory failure. The presence of the tracheostomy tube accomplishes multiple airway management goals; establishing a patent airway, as well as providing a connection to assisted ventilation (Robert & Argaud, 2007).
A uniform and broadly accepted definition of the term “weaning” is crucial to avoid confusion and is an essential prerequisite for interpreting the literature and guiding clinical decision-making. Weaning from mechanical ventilation is defined as “the process of withdrawing ventilator support” (Navalesi et al., 2014). It is commonly accepted that the process of weaning starts with the first spontaneous breathing trial (SBT), during which the patient is allowed to breathe for a relatively brief period of time (30–120 min) through a T-tube, or with low levels of either CPAP (2–5 cmH2O) or pressure support (≤ 8cmH2O). When the SBT is successful, the patient is considered weaned and ready to be extubated, provided that the natural airway is not at risk for obstruction.
A recently proposed and largely accepted classification based on the difficulty and duration of the weaning process includes: (1) simple weaning, i.e., the patient passes the initial SBT and is successfully extubated at the first attempt; (2) difficult weaning, i.e., up to three SBT or 7 days from the first SBT are necessary to withdraw mechanical ventilation and extubate the patient; (3) prolonged weaning, i.e., more than three SBTs or 7 days from the first SBT are required (Boles et al., 2007).
The variability of the potential influences on weaning success has created awareness that the process is facilitated by a “best practice” of collaborative multidisciplinary care. O’Bryan et al. (2002) described weaning protocols for a system of long-term acute care hospitals that included a consistent approach and protocol to weaning, the participation of rehabilitation services, and early and aggressive intervention as well as nutritional support. There is evidence that implementing standardized weaning protocols may reduce the duration of mechanical ventilation and length of stay in the Intensive Care Unit (ICU) patients (Blackwood et al., 2011). However, it is important that when applied specifically to the subset of patients with weaning difficulty, the use of “weaning protocols” are tailored to the individual patient, reflecting a holistic, multidisciplinary assessment, including consideration for the underlying cause and aggravating factors contributing to prolonged mechanical ventilation.
In the ICU, the majority of patients can be successfully liberated from mechanical ventilation without difficulty (Cohen & Booth 1994). However, up to 50% of the time a patient spends on the ventilator may be involved in the process of weaning from mechanical ventilation and approximately 14% of patients receiving mechanical ventilation undergo a “prolonged weaning” process (Esteban et al., 1994; Funk et al., 2010).
The Burden of Prolonged Weaning
A report from the UK revealed that 8% of ICU patients had “weaning delay” (defined as the need for ventilatory support for more than 2 weeks in the absence of any non-respiratory factor preventing weaning) and 7% had so-called “weaning failure” (if this state persisted for 3 weeks or more) (NHS Modernisation Agency, 2002). While for approximately 70% of patients, the weaning process is simple and successful; for the remaining 30%, the initial attempt fails, making the weaning difficult and worsening prognosis. ICU mortality has been reported to be as high as 25% in these patients, with about half progressing to prolonged weaning (Navalesi et al., 2014). Furthermore, patients with prolonged weaning account for 6% of all ventilated patients but consume 37% of ICU resources (Warren et al., 2003). From an economic perspective, US annual costs for mechanical ventilation are estimated to be 27 billion dollars, corresponding to more than 10% of all hospital costs. Each year, about 300,000 people receive prolonged mechanical ventilation in ICU’s in the US, and this number might double within the next decade, with costs increasing up 50 billion dollars (Zilberburg, 2008). Therefore, prolonged weaning carries not only a medical but also a significant social and economic burden.
The Role of Specialized Weaning Units and Multidisciplinary Teams
The appropriateness of the ICU environment for long-term management of patients undergoing prolonged weaning may be questioned by the detrimental consequences on the psychological and cognitive function of these patients, coupled with a paucity of ICU beds failing to adequately address demand. An otherwise stable patient who remains on mechanical ventilation may 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. The philosophy of such units lies in the delivery of holistic care from a truly multidisciplinary team encompassing a variety of specialties, including skilled nursing staff, physiotherapists (a designation used outside the US; within the US, the team would have respiratory therapists and physical therapists), physicians, speech-language pathologists, dieticians, psychologists, mental health services, social workers and palliative care.
Such an approach to “difficult weaning” would include an appreciation of the existence of underlying medical and psychological problems that may be contributing to weaning delay in each patient that may have been unrecognized in a busy ICU setting. These include the presence of chronic hypoventilation (failure to breathe rapidly enough or deeply enough), parenchymal lung disease (a group of lung diseases affecting the interstitium (the tissue and space around the air sacs of the lungs), neuromuscular conditions, cardiac disease, electrolyte abnormalities, nutritional deficiencies, inadequate muscle mass, and significant critical illness neuropathy. The tenets of care in specialized weaning units aim to focus on privacy, sleep quality, utilization of weaning protocols tailored to the individual patient, and optimizing comorbid medical conditions in an environment away from an acute ICU with the absence of invasive monitoring or multi-organ support (NHS Modernisation Agency, 2002).
To highlight the benefits of such an approach, a prospective study of 262 patients receiving prolonged invasive mechanical ventilation admitted to one such specialized unit in the UK over an 8-year period reported a successful outcome from weaning (i.e. liberation from invasive ventilation) in 64% of the patients (Mifsud Bonnici et al., 2016). Of those who were successfully weaned, 62% of those participants discharged were alive 12 months post discharge. Other observational studies report that 34–60% of patients in specialized weaning units can be weaned successfully from ventilatory support and suggest successful weaning can occur up to three months after admission to these SWU’s, without adversely affecting long-term mortality (Boles et al., 2007).
Initial Strategies for Patients Undergoing Prolonged Weaning
A preferred initial strategy is to maintain mechanical ventilation completely at nighttime; therefore, ensuring the patient has adequate “rest” during this period whilst aiming for either progressive ventilatory independence or a gradual reduction in the level of ventilator support in the daytime, depending on the individual patient. This initial approach is supplemented by regular detailed review of the patient’s swallow and bulbar function. When possible, progressive periods of tracheostomy cuff deflation during the daytime and allowing the patient to talk through speech devices, such as the Passy Muir® Tracheostomy & Ventilator Swallowing and Speaking Valve, are utilized. Allowing the patient to talk, regaining the sensation of taste and resuming oral, nutritional intake as early as feasible during the weaning process, carries significant physical and psychological benefits. The tracheostomy may also be downsized permitting the introduction of Non-Invasive Ventilation (NIV) early in the weaning process, if deemed safe and appropriate; still enabling the patient to receive ventilation by tracheostomy, if required. It is also imperative to ensure that aggressive secretion management occurs in patients, if successful liberation from tracheostomy ventilation is to occur.
The application of NIV in subjects with weaning difficulty has been shown in the literature to represent a useful strategy (Burns et al., 2013; Girault et al., 2011). Ferrer et al. (2003) investigated the use of NIV in weaning by randomizing 43 participants undergoing invasive mechanical ventilation who had failed a 2-hour T-piece trial for 3 consecutive days to either extubating and NIV or a “conventional” weaning plan consisting of continued daily weaning attempts. Liberation from invasive ventilation and 90-day survival were both greater in the NIV arm, where there was a significantly decreased incidence of nosocomial pneumonia and septic shock. A randomized controlled trial conducted in 13 ICUs comprised of 208 participants with chronic hypercapnic respiratory failure (respiratory failure with increased arterial carbon dioxide levels), who had failed an SBT, found that the group who was extubated to NIV had a significantly reduced occurrence of acute respiratory failure post-extubation compared to those extubated to oxygen therapy or those who continued a weaning strategy using Intermittent Mandatory Ventilation (IMV) (Girault et al., 2011). The results from these studies suggest that NIV represents a useful tool in the management of patients undergoing a prolonged weaning process.
High Flow Nasal Oxygen Therapy
Another technique that has a potentially useful application in the weaning process is that of High Flow Nasal Oxygen Therapy (HFNOT). HFNOT aims to derive greater physiological benefit by delivering heated and humidified oxygen therapy through a nasal cannula at higher flow rates (up to 60 liters/minute) when compared to standard oxygen delivery devices (Spoletini et al., 2015). This results in greater washout of the upper airway dead space facilitating removal of carbon dioxide. It also results in delivery of a small degree of Positive End Expiratory Pressure (PEEP), allowing alveolar recruitment, thus aiming to reduce the work of breathing as well as maintaining patient comfort through the delivery of warm humidified gas. At present, there is a paucity of high-quality evidence examining the utility of HFNOT in subjects undergoing prolonged weaning despite some data pointing to improvements in oxygenation with HFNOT in this cohort (Corley et al., 2017). In a multi-center study comparing 604 extubated patients deemed at high risk of re-intubation randomized to either HFNOT or NIV post-extubation, no significant differences were noted in the rate of re-intubation or in-hospital mortality (Hernandez et al., 2016). Whilst such data is encouraging, further research is needed in this area to identify those subgroups of patients with weaning difficulty who may benefit from the use of HFNOT as a tool in the liberation from mechanical ventilation.
Management of Comorbidities
Adequate management of comorbidity also is integral to the management of patients with weaning difficulties. For example, it is important that healthcare professionals pay attention to fluid overload and to the optimization of cardiac function during the weaning process. A weaning strategy that includes fluid management driven by serum B-type natriuretic peptide (BNP) levels has been shown to confer superior outcomes in terms of duration of weaning and time to successful extubation when compared to a more conventional approach with no significant differences in terms of incidence of electrolyte abnormalities and renal failure between the two groups. A potential mechanism postulated to explain the beneficial outcomes reported of such a biomarker based approach may lie in the reduction of Ventilator Associated Pneumonia (VAP) as pulmonary edema may affect the alveolar bacterial clearance (Mekonto Dessap et al., 2014).
Role of Allied Health Professionals and Trach Teams
The role of Physical Therapy and Occupational Therapy at an early stage in the management of patients aiming to be liberated from mechanical ventilation cannot be over-emphasized. Early physical and occupational therapy is feasible from the onset of mechanical ventilation, despite high illness acuity and presence of life support devices. Adverse events are uncommon, even in this high-risk group (Pohlman et al., 2010). This includes multiple domains such as early mobilization and transferring, attention to posture and balance, maintenance of muscle mass, peripheral muscle training, airway secretion management, and respiratory muscle training (Ambrosino et al., 2012). To emphasize the importance of rehabilitation, the “real world” service review reported that 48.1% of patients admitted to a specialist weaning unit in the UK were discharged to the referring hospital for on-going rehabilitation needs (Mifsud Bonnici et al., 2015).
Another area of utmost importance in the management of subjects with weaning difficulty is the role of Clinical Psychology and Mental Health services. The impact of prolonged mechanical ventilation and the events leading to the ICU admission may carry a significant burden both on patients and family members in terms of depression, anxiety, and other mental health issues and this may be overlooked by healthcare professionals in a busy ICU environment. In a seminal study, depressive disorders were found to be present in 42% of patients undergoing weaning difficulty and were associated both with weaning failure and an elevated mortality rate (Jubran et al., 2010b). These issues may persist even after the weaning period; highlighting the importance of creating a structured holistic follow-up program for patients following discharge from the hospital. Beyond healthcare professionals simply recognizing such conditions, it is worth appreciating that such a traumatic experience may greatly alter the patient’s perception of the environment around them, their progress during the process of being liberated from the ventilator, medical interventions and actions of healthcare professionals caring for them. Nutritional status is integral in the weaning process. Patients with tracheostomy who are dependent on ventilators, and who have decreased nutritional intake, may experience protein–calorie malnutrition, which reduces respiratory muscle strength and function. Registered Dieticians play an integral part in the nutritional management of such patients. Through special enteral feeding formulas and oral supplements, dieticians can address hypoalbuminemia(low level of albumin in the body) and heal and prevent pressure ulcers, while maintaining optimal support for weaning. When an oral diet is recommended, Speech-Language Pathologists and Registered Dieticians work closely together to maximize caloric intake, modifying consistencies as needed to achieve appropriate nutrition and hydration in the safest and most effective manner.
Placement of a tracheostomy tube may be necessary for patients in the ICU with respiratory failure. In fact, the incidence of tracheostomy seems to be increasing out of proportion to the increased need for mechanical ventilation. This has led some hospitals to develop specialized tracheostomy teams to standardize and deliver specialized patient care to reduce perioperative tracheostomy-related complications; typically delivered by multiple providers, including the primary physician, resident, mid-level providers, consulting surgeon, nurse, Respiratory Therapist, and Speech-Language Pathologist. Multidisciplinary tracheostomy and wean teams have been successful in improving patient outcomes. One study showed that the addition of a post-tracheostomy care bundle to a multidisciplinary tracheostomy service significantly improved rates of decannulation and tolerance of oral diet (Mah et al., 2016). Standardized care provided by a specialized multidisciplinary tracheostomy team also was associated with fewer tracheostomy-related complications and an increase in the use of speaking valves (Mah et al., 2016).
Role of the Speech-Language Pathologist (SLP) in Patients Undergoing Prolonged Weaning
Speech-Language Pathologists (SLPs) address the communication and swallowing needs of the tracheostomized and ventilator-dependent population throughout the course of the patient’s recovery. Adults who are tracheotomy and ventilator dependent or who are undergoing prolonged weaning are some of the most challenging patients in the caseload of an SLP. Airway issues influence many aspects of patient care, including swallowing. The medical issues for patients with these complex cases greatly affect their rehabilitation. Physicians, SLPs, and other members of the multidisciplinary team must work together in their management, especially to understand the influence of pulmonary physiology on swallowing and swallowing dysfunction. Often, these tracheostomized and ventilator dependent patients have long-term alternative feeding methods placed early in their acute medical course. Without SLP intervention, these patients may never return to an oral diet. Communication and swallowing management can greatly enhance the quality of life for these long-term mechanically ventilated individuals.
Deglutition and respiration are shared systems. Remediation of swallowing function can assist in the weaning and decannulation process by restoring airflow to the upper airway and addressing airway protection deficits. The entire medical team must have an appreciation for the timing of swallowing management with other medical interventions, such as weaning, and make appropriate adjustments to the patient’s plan of care. For those individuals where weaning from mechanical ventilation is not possible, the ability to take even a small amount of oral intake can greatly improve their quality of life (Dikeman & Kazandjian, 2000). The clinical literature does not support a direct, causal relationship between tracheostomy, mechanical ventilation, and swallowing impairment; however, the clinical course of these medically fragile patients typically includes a disruption of swallowing function (Donzelli et al., 2005). Many of these patients receive feeding tubes simultaneously with the tracheotomy, without a swallow assessment. This may result in the patient’s long-term non-oral status, influencing an important aspect of quality of life. For some individuals, the events that led to respiratory failure and the need for mechanical ventilation may create dysphagia or exacerbate dysphagia that is already present. In addition, the presence of dysphagia may affect the individual’s ability to wean from ventilation. The consequences of pulmonary aspiration may be more significant for patients already in an immuno-compromised state, who are often malnourished, have multiple medical issues, and are receiving polypharmacy (Langmore, 1996).
This is a key issue for ventilated patients, who find the inability to speak distressing (Dikeman et al., 2000). Difficulties with communication in the tracheostomy patient population have been associated with social withdrawal, leading to depression, lack of motivation to participate in care (Leder, 1990; Freeman-Sanderson et al., 2016), poor sleep, and increased anxiety and stress levels (Egbers, 2014; Freeman-Sanderson et al., 2016) which have both short-term and long-term impacts on patient outcomes in ICU and post ICU stays. By demonstrating the potential physiological benefits on top of the already known and more obvious psychological benefits, speaking valves present an excellent way to improve patient care in the ICU.
Use of Speaking Valves
The inability to communicate during periods of mechanical ventilation (MV) can significantly increase psycho-emotional distress (Egbers et al., 2014) and has been associated with depression and post- traumatic stress disorder (Jubran et al., 2010a). One-way speaking valves can be used to restore verbal communication for patients who require MV. The Passy Muir® Valve is the only bias-closed position valve that can be used during MV. The Passy Muir Valve opens during inspiration and closes at the end of inspiration, re-directing exhalation through the vocal cords and out through the mouth and nose, which allows for verbal communication. The restoration of airflow, sensation, and positive airway pressure to the aerodigestive tract returns the upper airway to a more normal physiologic condition and may also have other clinical benefits for the patient who requires tracheostomy and MV. Speaking valves can be used in-line with mechanical ventilation but use of these requires deflation of the tracheostomy cuff.
It is not uncommon, however, for the SLP to meet resistance when requesting cuff deflation. There is still the misconception that the cuff prevents aspiration. There is also a fear that adequate ventilation cannot be achieved. The SLP can provide education and evidence to alleviate these concerns. It has been demonstrated that ventilation and stable respiratory parameters can be achieved with the cuff fully deflated and with placement of a Passy Muir Valve. Most recently, clinicians in a cardiothoracic ICU were able to reveal that deflating the cuff and using the Passy Muir Valve increased end expiratory lung impedance, therefore serving as a lung recruitment intervention (Sutt & Fraser, 2015). Due to these findings, use of Passy Muir Valves with ventilator patients increased from 0% to 70% and is now the standard of care in that ICU.
The SLP must work closely with the Respiratory Care Practitioner (RCP) and Respiratory Therapists (RTs) to understand how particular ventilator settings and the level of patient control of breathing may impact the patient’s ability to synchronize breathing and swallowing. Using the Passy Muir Valve in-line may require ventilator adjustments to assure patient comfort, safety, adequate ventilation and ability of the patient to perform speech and swallow tasks. These adjustments are made by the RCP/RT trained in such procedures under the guidance of the physician. For the ventilated patient, the team determines the roles of the RCP and SLP as related to cuff deflation and placement of the Valve in-line with the ventilator circuitry. The RCP typically is responsible for procedures such as downsizing the tracheostomy tube and adjustments to the ventilator settings as stipulated in the facility’s Policy and Procedures.
Therefore, the SLP-RCP team is presented with a unique opportunity to co-treat patients who require tracheostomy ventilation to provide not only a way to communicate, but also to restore airflow and engage the glottis, restore positive pressure to the aerodigestive tract, and address rehabilitation of the aerodigestive system as needed. This therapy may enhance weaning and rehabilitation by promoting safer swallowing to reduce aspiration, improved swallow and cough (Pitts, et al., 2009), reducing respiratory infections, promoting alveolar recruitment (Sutt et al., 2015,) and by enhancing early mobilization efforts (Mah et al., 2016).
In summary, prolonged weaning from mechanical ventilation constitutes a significant burden in terms of morbidity and mortality in the ICU. Successful liberation of such patients from mechanical ventilation lies in availing a multidisciplinary approach to care in any setting, developing specialist weaning units, and following standard weaning protocols. When working with patients who are being weaned from mechanical ventilation, clinicians must appreciate the interaction between respiration, swallowing, and communication systems. Impairment in these systems is closely linked; and in conjunction with other comorbidities of chronic illness, such as recurrent infections and decreased nutrition, the ventilator weaning process is often challenging. Multidisciplinary teams must work together to facilitate patient recovery and liberation from mechanical ventilation.
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