Pneumothorax associated with mechanical insufflation-exsufflation and related factors

Impaired cough that results in ineffective airway secretion clearance is an important contributor to pulmonary complications in patients with neuromuscular weakness including spinal cord injury. Mechanical insufflation-exsufflation (MI-E) is a respiratory aid used by patients with weak respiratory muscles to increase cough peak flows and improve cough effectiveness. Relative contraindications to MI-E are said to include susceptibility to pneumothorax, but the association of pneumothorax with MI-E use has never before been described. We report two cases of pneumothorax in patients with respiratory muscle weakness associated with daily use of MI-E: one was a 58-yr-old male with C4 ASIA C tetraplegia, and the other was a 26-yr-old male with Duchenne muscular dystrophy. Both patients also used positive-pressure ventilatory assistance. Although seemingly rare in this patient population, ventilator users also using MI-E who have increasing dyspnea or who require increasing positive inspiratory pressures when using noninvasive ventilation should be evaluated for pneumothorax.     

Mechanical insufflation-exsufflation improves outcomes for neuromuscular disease patients with respiratory tract infections

OBJECTIVES: The efficacy of mechanical insufflation-exsufflation, in addition to standard chest physical treatments, was investigated as a first-line intervention for patients with neuromuscular diseases with respiratory tract infections and airway mucous encumbrance. DESIGN: The short-term outcomes of 11 consecutive neuromuscular disease patients with respiratory tract infections and tracheobronchial mucous encumbrance who were administered mechanical insufflation-exsufflation and conventional chest physical treatments in an intensive care unit were compared with the outcomes of 16 historical matched controls who had received chest physical treatments alone. Treatment failure was defined as the need for cricothyroid "minitracheostomy" or endotracheal intubation, despite treatment. The number of subjects administered bronchoscopy-assisted aspiration during the hospital stay was also compared. RESULTS: Treatment failure was significantly lower (P < 0.05) in the mechanical insufflation-exsufflation group than in the conventional chest physical treatments group (2/11 vs. 10/16 cases). The use of bronchoscopy-assisted aspiration was similar in the two groups (5/11 vs. 6/16 cases). Mechanical insufflation-exsufflation did not produce serious side effects and was well tolerated by all subjects. CONCLUSIONS: Provision of mechanical insufflation-exsufflation in combination with standard chest physical treatments may improve the management of airway mucous encumbrance in neuromyopathic patients; its use should be included in the noninvasive approach to treatment of respiratory tract infections with impaired mucous clearance.     

Management of airway clearance in neuromuscular disease

The clearance of airway secretions from the lungs is normally supported by the mucociliary escalator and by cough. These protective mechanisms provide an effective means of pulmonary-hygiene maintenance in healthy individuals. Patients with neuromuscular disease that affects the respiratory pump (the muscles of breathing) can experience mild to profound limitation in both ventilation and cough. Neuromuscular respiratory insufficiency, when left untreated, can substantially impact quality of life and life expectancy. In most cases of neuromuscular disease, respiratory failure and pneumonia are the primary causes of death. Invasive mechanical ventilation and tracheal suctioning have been successfully used when needed to support respiratory insufficiency in this population. These modalities, though supportive, have been associated with substantial morbidity when used in patients with neuromuscular disease. The advent of noninvasive ventilation as a means of supporting chronic neuromuscular respiratory insufficiency has spurred the development of noninvasive cough-augmentation therapy to support airway clearance. Unfortunately, the need to support cough clearance is not always addressed, and few guidelines for the management of cough insufficiency have existed until relatively recently. An understanding of neuromuscular respiratory pathophysiology and the modes of effective noninvasive cough support are key in the evaluation and management of neuromuscular diseases. This review is meant to provide a basic understanding of cough mechanics, and the pathophysiology and management of neuromuscular cough insufficiency.     

Systematic review of techniques to enhance peak cough flow and maintain vital capacity in neuromuscular disease: the case for mechanical insufflation–exsufflation

Abstract

Patients with neuromuscular disease risk developing chest infections due to the inability to cough effectively and to maintain adequate lung volume. This systematic review aimed to evaluate the comparative effectiveness of techniques used in the respiratory management of these patients. Articles evaluating peak cough flow measurements and maintenance of lung volumes only were selected to retain a specific focus for comparison. A database search was performed using the Cochrane controlled register, AMED, Cinahl, Medline and PEDro. Various techniques improved cough efficacy in neuromuscular disease by increasing peak cough flow values and maintaining lung volume. Mechanical insufflation–exsufflation is a technique used to augment cough strength, producing the greatest increase in peak cough flow compared with other techniques. These findings highlight the treatment options for the patient with neuromuscular disease in order to maintain respiratory muscle length, prevent infection and augment peak cough flow.     

Ventilator weaning by lung expansion and decannulation

This case series of ventilator-dependent patients with neuromuscular disease who had no ventilator-free breathing ability demonstrates that decannulation and switching to continuous noninvasive intermittent positive-pressure ventilation combined with regular lung expansion therapy can result in improvements in pulmonary function and at least partial ventilator weaning. These six patients were also managed using mechanical insufflation-exsufflation for regular lung expansion and cough assistance. Thus, some ventilator users with neuromuscular disease can benefit from tracheostomy tube decannulation and transition to noninvasive intermittent positive-pressure ventilation and assisted coughing for ventilator weaning to predominantly nocturnal-only use.     

Ineffective airway clearance related to neuromuscular dysfunction

Individuals with neuromuscular dysfunction are at increased risk for secretion retention. Their underlying disease process compromises or prevents ability to cough effectively. Although their lung function may remain normal, neuromuscular disease predisposes to breathing at low lung volumes and to elimination of sighing respirations, a breathing pattern which predisposes to development of airway and alveolar collapse. As ventilatory reserve decreases, risk of progressive atelectasis and secretion retention is increased. Prompt recognition of the signs and symptoms of this nursing diagnosis can prevent or reverse problems relating to ineffective airway clearance. Nursing management thus becomes the cornerstone of the individual's regimen of care.     

Forced expiratory technique, directed cough, and autogenic drainage

In health, secretions produced in the respiratory tract are cleared by mucociliary transport, cephalad airflow bias, and cough. In disease, increased secretion viscosity and volume, dyskinesia of the cilia, and ineffective cough combine to reduce secretion clearance, leading to increased risk of infection. In obstructive lung disease these conditions are further complicated by early collapse of airways, due to airway compression, which traps both gas and secretions. Techniques have been developed to optimize expiratory flow and promote airway clearance. Directed cough, forced expiratory technique, active cycle of breathing, and autogenic drainage are all more effective than placebo and comparable in therapeutic effects to postural drainage; they require no special equipment or care-provider assistance for routine use. Researchers have suggested that standard chest physical therapy with active cycle of breathing and forced expiratory technique is more effective than chest physical therapy alone. Evidence-based reviews have suggested that, though successful adoption of techniques such as autogenic drainage may require greater control and training, patients with long-term secretion management problems should be taught as many of these techniques as they can master for adoption in their therapeutic routines.     

Peak Cough Flow Fails to Detect Upper Airway Collapse During Negative Pressure Titration for Cough-Assist

ObjectiveTo study the ability of peak cough flow (PCF) and effective cough volume, defined as the volume exsufflated >3 L/s, to detect upper airway collapse during mechanical insufflation-exsufflation (MI-E) titration in neuromuscular patients.DesignProspective observational study.SettingRehabilitation hospital.ParticipantsPatients (N=27) with neuromuscular disease causing significant impairment of chest wall and/or diaphragmatic movement.InterventionsThe lowest insufflation pressure producing the highest inspiratory capacity was used. Exsufflation pressure was decreased from ?20 cm H₂O to ?60/?70 cm H₂O, in 10-cm H₂O decrements, until upper airway collapse was detected using the reference standard of flow-volume curve analysis (after PCF, abrupt flattening or flow decrease vs previous less negative exsufflation pressure).Main Outcome MeasuresPCF and effective cough volume profiles during expiration with MI-E.ResultsUpper airway collapse occurred in 10 patients during titration. Effective cough volume increased with decreasing expiratory pressure then decreased upon upper airway collapse occurrence. PCF continued to increase after upper airway collapse occurrence. In 5 other patients, upper airway collapse occurred at the initial ?20 cm H₂O exsufflation pressure, and during titration, PCF increased and effective cough volume remained unchanged at <200 mL. PCF had 0% sensitivity for upper airway collapse, whereas effective cough volume had 100% sensitivity and specificity.ConclusionOf 27 patients, 15 experienced upper airway collapse during MI-E titration. Upper airway collapse was associated with an effective cough volume decrease or plateau and with increasing PCF. Accordingly, effective cough volume, but not PCF, can detect upper airway collapse.     

The measurement of the work of breathing for the clinical assessment of ventilator dependence

The work of breathing was measured in 10 normal subjects and in 28 critically ill patients with acute complications of obstructive pulmonary disease treated with assisted ventilation. The measurement of the work of breathing was found to be a useful objective variable for determining the capability for independent ventilation. Dependence on mechanical ventilation was observed when the respiratory work was greater than or equal to 1.7 kg-m/min. Patients were ordinarily capable of spontaneous ventilation when the respiratory work was less than or equal to 1.0 kg-m/min. Discontinuation of assisted ventilation was likely to be successful in those patients whose respiratory work was less than or equal to 1.5 kg-m/min if the patient was able to increase and maintain his work capability by a factor of two when breathing against an inspiratory resistance of 5 cm H2O for 10 min. Failure to increase the respiratory work when breathing against an inspiratory resistance indicated limitations in respiratory mechanics and was associated with the need for prolonged assisted ventilation. The measurement of the work of breathing against an inspiratory resistance of 5 cm H2O was useful in the identification and quantification of ventilatory reserve in patients with obstructive pulmonary disease.     

Maximum insufflation capacity: vital capacity and cough flows in neuromuscular disease

OBJECTIVE: To investigate the relationships between vital capacity (VC), maximum insufflation capacity (MIC), and both unassisted and assisted peak cough flows (PCFs). DESIGN: The 108 patients were divided into two groups, those whose MICs were greater than their VCs (group 1) and those whose MICs could not exceed their VCs (MIC = VC, or group 2). RESULTS: The MIC correlated positively with the VC for group 1 patients, but the percent increase in MIC correlated negatively with VC. Both VC and MIC correlated significantly with both unassisted and assisted PCF, respectively. Assisting the cough increased the PCF of 37 patients over a previously defined critical level of 2.7 L/sec. The MIC VC difference and percent increase in MIC also correlated significantly with the difference between unassisted and assisted PCF. Although the group 2 patients did not have true cough flows because of inability to close the glottis, their peak expiratory flows were significantly less than the unassisted and assisted PCF of the group 1 patients. CONCLUSIONS: The greater the MIC VC difference, the greater the PCF, and, thereby, the ability to expel airway mucus and avert respiratory complications. The lower the VC, the greater the percent increase in MIC and the greater the percent increase in assisted PCF. Maximal insufflations are extremely important to increase PCF for patients with neuromuscular conditions who have VCs of < 1500 ml.     

Respiratory dysfunction and management in spinal cord injury

Respiratory dysfunction is a major cause of morbidity and mortality in spinal cord injury (SCI), which causes impairment of respiratory muscles, reduced vital capacity, ineffective cough, reduction in lung and chest wall compliance, and excess oxygen cost of breathing due to distortion of the respiratory system. Severely affected individuals may require assisted ventilation, which can cause problems with speech production. Appropriate candidates can sometimes be liberated from mechanical ventilation by phrenic-nerve pacing and pacing of the external intercostal muscles. Partial recovery of respiratory-muscle performance occurs spontaneously. The eventual vital capacity depends on the extent of spontaneous recovery, years since injury, smoking, a history of chest injury or surgery, and maximum inspiratory pressure. Also, respiratory-muscle training and abdominal binders improve performance of the respiratory muscles. For patients on long-term ventilation, speech production is difficult. Often, practitioners are reluctant to deflate the tracheostomy tube cuff to allow speech production. Yet cuff-deflation can be done safely. Standard ventilator settings produce poor speech quality. Recent studies demonstrated vast improvement with long inspiratory time and positive end-expiratory pressure. Abdominal binders improve speech quality in patients with phrenic-nerve pacers. Recent data show that the level and completeness of injury and older age at the time of injury may not be related directly to mortality in SCI, which suggests that the care of SCI has improved. The data indicate that independent predictors of all-cause mortality include diabetes mellitus, heart disease, cigarette smoking, and percent-of-predicted forced expiratory volume in the first second. An important clinical problem in SCI is weak cough, which causes retention of secretions during infections. Methods for secretion clearance include chest physical therapy, spontaneous cough, suctioning, cough assistance by forced compression of the abdomen ("quad cough"), and mechanical insufflation-exsufflation. Recently described but not yet available for general use is activation of the abdominal muscles via an epidural electrode placed at spinal cord level T9-L1.     

Mechanical insufflation-exsufflation vs. tracheal suctioning via tracheostomy tubes for patients with amyotrophic lateral sclerosis: a pilot study

OBJECTIVE: To compare the effects of mechanical insufflation-exsufflation vs. suctioning via tracheostomy tubes on respiratory variables for six amyotrophic lateral sclerosis patients. DESIGN: In this prospective crossover study, six consecutive patients with amyotrophic lateral sclerosis who required continuous mechanical ventilation via tracheostomy tubes and developed chest infections underwent measurement of pulse oxyhemoglobin saturation (SpO2), peak inspiratory pressure (PIP), mean airway pressure (Pawm), and work of breathing performed by the ventilator (WOBv) at baseline and 5 and 30 min after tracheal suctioning and 5 min after mechanical insufflation-exsufflation. RESULTS: The baseline values were 93.50 +/- 2.26% for SpO2 in ambient air, 18.50 +/- 4.23 cm H2O for PIP, 4.67 +/- 1.37 cm H2O for Pawm, and 1.03 +/- 0.25 J/liters for WOBv. Only WOBv changed significantly, decreasing after tracheal suctioning (P < 0.05), whereas all variables improved significantly after mechanical insufflation-exsufflation. CONCLUSION: For ventilator-dependent patients with amyotrophic lateral sclerosis, mechanical insufflation-exsufflation via a tracheostomy tube with an inflated cuff may be more effective in eliminating airway secretions than conventional tracheal suctioning.     

Strategies for maximizing your chances for weaning success. Limitations--and advantages--of common predictive indices

Using indices to predict weaning outcome can avoid premature extubation and unnecessary prolongation of ventilatory support. Unfortunately, none of the indices is consistently able to predict outcome. The key to successful weaning is to assess respiratory function repeatedly with several indices, not just one. The patient should be able to sustain spontaneous breathing for at least 24 hours on minimal partial ventilatory support (a pressure support or a continuous positive airway pressure of 5 cm H2O or a T piece, for example). Indices of maximal inspiratory pressure; work of breathing; and rapid, shallow breathing are useful in evaluating a patient's respiratory muscle performance; airway occlusion pressure is helpful as well when increased neuromuscular drive is a problem.     

"Ineffective breathing pattern" care for COPD patients

Chronic obstructive pulmonary disease (COPD) is a long-term, chronic respiratory disease from which patients never fully recover. COPD patients usually face abnormal aeration caused by the disease. Patients that are unable to breathe and aspirate adequately and maintain lung appropriate expansion and contraction are considered to have ineffective breathing patterns. This causes physical, psychological and behavioral changes in COPD patients and impacts their emotional condition, daily activities and quality of life. Nurses who care for COPD patients with ineffective breathing patters can improve breathing muscle functions, improve respiration and keep the airway clean. In this paper, the author reviews and integrates relevant findings on this subject from the empirical literature in order to assist clinical nurses responsible for the care of COPD patients.     

Noninvasive ventilation in chronic obstructive lung disease

Noninvasive mechanical ventilation is provided without establishing an endotracheal airway. In acute respiratory failure due to chronic obstructive lung disease, noninvasive positive-pressure ventilation delivered through a nasal or face mask may eliminate the need for intubation and related complications, reduce the duration of hospitalisation and improve survival compared to assisted ventilation through an endotracheal tube. In chronic respiratory failure related to neuromuscular diseases and thoracic deformities, the advent of noninvasive intermittent longterm ventilation is well established. However, it is not clear, whether addition of noninvasive ventilation to standard treatment with medication and longterm oxygen improves symptoms and survival in chronic respiratory failure due to chronic obstructive lung disease. During introduction of noninvasive ventilation, patients must be monitored closely. Patient selection and information, meticulous optimization of the ventilator settings and delivery system, education and experience of the personnel have an important impact on the success of this novel way of providing mechanical ventilatory support.     

三球式呼吸训练器联合气道廓清技术对慢性阻塞性肺疾病急性加重患者康复效果的影响

目的:探讨三球式呼吸训练器联合气道廓清技术对慢性阻塞性肺疾病急性加重(AECOPD)患者康复效果的影响。方法:将102例AECOPD患者按照随机数字表法分为观察组(予以三球式呼吸训练器联合气道廓清技术)与对照组(予以气道廓清技术),各51例。对比2组干预前后痰量、痰色评分、黏液粘稠度、第1秒用力呼气容积占预计值百分比(FEV1%预计值)、每分钟最大通气量占预计值百分比(MVV%pred)、FEV1/用力肺活量(FVC)、气道峰压、呼吸压力、气道阻力。结果:干预后2组痰量、痰色评分均较干预前降低(P<0.05),观察组更低于对照组(P<0.05)。干预后2组黏液粘稠度较干预前有所改善(P<0.05)。观察组黏液粘稠度改善程度优于对照组(P<0.05)。重复测量方差分析显示，2组FEV1预计值%、MVV%pred、FEV1/FVC存在时间、组间及时间与组间交互作用，差异有统计学意义(P<0.05);干预7、14d后2组FEV1预计值%、MVV%pred、FEV1/FVC均较干预前逐渐提高(P<0.05),2个时间点观察组FEV1预计值%、MVV%pred...     

Respiratory issues in the management of children with neuromuscular disease

Most children with neuromuscular disease eventually require assistance with airway clearance and with breathing, especially during sleep. Techniques and devices for airway clearance and noninvasive ventilation that are commonly used in adults have been successfully adapted for use in infants and young children. Both physiological differences and small size of young patients with neuromuscular disease, however, can limit the applicability of such interventions or require special consideration. Measurements to identify the appropriate time to begin airway clearance assistance are lacking for young children, and the role of early introduction of noninvasive ventilation to preserve or enhance lung growth and chest-wall mobility remains to be elucidated. The paucity of nasal interfaces and headgear commercially made for small patients can reduce patient tolerance of noninvasive ventilation and exacerbate patient-ventilator dyssynchrony. Despite these issues, a greater number of children with neuromuscular diseases are living well past their second decade. Strategies to transition these patients to appropriate adult-care providers, to secure cost-effective health care for them, and to help integrate them into adult society must be developed.     

Myasthenia gravis: a nursing perspective

Myasthenia gravis, a chronic neuromuscular disease, results in weakness of striated voluntary muscles. The muscles involved and the degree of weakness vary from patient to patient. Nursing care of the patient with muscle weakness from myasthenia gravis presents a challenge for the neuroscience nurse. Drug therapy and thymectomy treatments are discussed, along with their complications. Nursing interventions for other problems for the myasthenic patient, including impaired breathing patterns, inability to clear the airway, impaired communication, altered nutrition, self-care deficits, and impaired vision are described.     

Duchenne muscular dystrophy: prolongation of life by noninvasive ventilation and mechanically assisted coughing

OBJECTIVE: To quantitate prolongation of survival for patients with Duchenne muscular dystrophy with the use of noninvasive intermittent positive-pressure ventilation (IPPV) with and without access to a protocol involving mechanically assisted coughing. DESIGN: In this retrospective review of all patients with Duchenne muscular dystrophy visiting a neuromuscular disease clinic, patients were trained to use mouth piece and nasal IPPV and mechanically assisted coughing to maintain oxyhemoglobin saturation >94% (protocol). Survival was considered prolonged when noninvasive IPPV was required full time. RESULTS: Ninety-one of 125 patients used noninvasive IPPV part time for 1.9 +/- 1.3 yr, and 51 went on to require it full time for 6.3 +/- 4.6 yr. Of the 31 noninvasive IPPV users who died without access to the protocol, 20 died from respiratory causes and seven died from cardiac causes. None of the 34 full-time noninvasive IPPV users with access to the protocol underwent tracheotomy or died from respiratory complications during a period of 5.4 +/- 4.0 yr, whereas three died from heart failure. Five patients with no breathing tolerance were extubated or decannulated to continuous noninvasive IPPV. CONCLUSIONS: Noninvasive respiratory aids can prolong survival and permit extubation or decannulation of patients with Duchenne muscular dystrophy with no breathing tolerance.     

Airway clearance: physiology, pharmacology, techniques, and practice

Clinicians and their patients are troubled by respiratory secretions, and standard practice calls for efforts to clear secretions from the lungs. On one hand, mucus production and cough are important for airway defense and protection of the lower respiratory tract against inhaled irritations. On the other hand, excessive mucus obstructs airways and excessive cough has been associated with a number of complications. The objective of this conference was to review the scientific basis and clinical evidence for the use of airway clearance therapy to guide the most appropriate approach to airway clearance. An international group of clinicians and scientists addressed the physiology of mucus production and cough, pharmacologic approaches to airway clearance, and the variety of techniques available for airway clearance. Specific issues related to airway clearance in critically ill patients, children, and the elderly were discussed. Outcome measures related to evaluating mucus clearance therapy were also presented. One of the themes repeated consistently throughout this conference was the dearth of high-level evidence related to airway clearance techniques. Appropriately powered and methodologically sound research is desperately needed in this area.