Current Issue
JUNE 2001 - VOLUME 21 - NUMBER 3
PULMONARY CARE
Caring for Adults With Cystic Fibrosis
Debbie Wilmoth, Peggie E. Walters, Roy Tomlin, and Stacey F. McCray
About the Authors
By Debbie Wilmoth, RN, MSN, CCRN, Peggie E. Walters, RN, MSN, Roy Tomlin, RN, BSN, CCRN, and Stacey F. McCray, RD, CNSD. All authors are employed at the University of Virginia Health System, Charlottesville, Va.
Debbie Wilmoth is a clinician 4 and the nursing education coordinator for the Porter Medical Intensive Care Unit. Peggie Walters is a clinician 4 and the adult cystic fibrosis nurse coordinator. Roy Tomlin is a clinician 3 in the Porter Medical Intensive Care Unit. Stacey McCray is a member of the medical nutritional support team.
This article originally appeared in the June 2001 issue of Critical Care Nurse, Vol 21, No. 3. Reprint requests: The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Phone, (800) 899-1712 or (949) 362-2050 (ext 515); fax, (949) 362-2022; e-mail, reprints@aacn.org.
Cystic fibrosis was once a disease that had relevance only for pediatric nurses, because patients who had this disease had such a short life expectancy. The natural history of cystic fibrosis is changing. The most recent statistics from the Cystic Fibrosis Foundation indicate that the mean survival age of patients with cystic fibrosis is currently 31.3 years.1 Critical care nurses who work with adult patients must become familiar with cystic fibrosis and its treatment. In this article, we review the pathophysiology and the multisystem nature of cystic fibrosis and discuss treatments and nursing implications for adult patients with this disease who are admitted to an intensive care unit (ICU). A case report illustrates the multidisciplinary therapeutic approach used in the care of a young woman with cystic fibrosis.
Background
Cystic fibrosis, a disease of the exocrine glands, is the most common lethal genetic disorder in whites; it affects 30 000 children and adults in the United States.2 Patients with cystic fibrosis have abnormally thick, tenacious mucus that clogs the lungs and the pancreas. Lung disease in patients with cystic fibrosis is characterized by a vicious cycle of chronic airway inflammation and infection that eventually causes airway destruction, obstructive lung disease, and bronchiectasis. More than 90% of patients with cystic fibrosis die of respiratory failure.3 The increased viscosity of pancreatic secretions results in blockage of pancreatic ducts, which prevents digestive enzymes from reaching the intestine. The resulting malabsorption of carbohydrates, protein, and fat leads to poor nutrition and abnormal growth patterns.
Cystic fibrosis has its origin in mutations of a gene discovered only recently, in 1989. The gene encodes a protein called cystic fibrosis transmembrane conductance regulator (CFTR) that is present in epithelial cells of the respiratory, gastrointestinal, and reproductive tracts, as well as in sweat glands. CFTR helps control the flow of sodium and chloride ions across the surface of the epithelium, affecting the hydration of secretions. Although the exact mechanism remains unclear, abnormal CFTR most likely alters the ion permeability of the cell membrane, making epithelial cells relatively impermeable to chloride. This impermeability and the hyperabsorption of sodium from the lumen of the airway decrease the chloride, sodium, and water content of airway surface fluid, resulting in dehydrated secretions.4
Manifestations of Cystic Fibrosis
Clinical manifestations of cystic fibrosis vary, depending upon the specific CFTR mutation present. Mild cases may not be diagnosed until adulthood. More commonly, cystic fibrosis is a multisystem disease in which almost all patients have chronic sinopulmonary involvement, and up to 90% have exocrine pancreatic insufficiency (Table 1).
Pulmonary Manifestations
The hallmark of cystic fibrosis is lung disease characterized by airway obstruction with thick, tenacious sputum. The increase in sputum viscosity is due to dehydration of the airways and the release of DNA from degeneration of the large numbers of neutrophils present in the airways as part of the inflammatory response. The viscosity of secretions interferes with normal mucociliary transport, resulting in stasis of secretions and providing an ideal medium for bacterial growth. Infection gradually damages the airway endothelium, predisposing the airway to chronic colonization, first with Staphylococcus aureus and later with Pseudomonas aeruginosa. The subsequent inflammatory response is ineffective in clearing the infection but results in airway edema and damage due to the release of oxidants and proteases, with eventual airway destruction. The inflammatory process is self-perpetuating, and the result is more and more destruction, ending in bronchiectasis with dilatation and loss of elasticity of the airways (Figure 1).
Patients with cystic fibrosis experience chronic pulmonary infection punctuated with acute exacerbations. Patients have chronic cough productive of large amounts of purulent sputum, which is often brown, green, or gray. Chest radiographs reveal chronic changes, including bronchiectasis, atelectasis, infiltrates, and hyperinflation (Figure 2). Airway obstruction is characterized by wheezing and air trapping.5
Because of the obstructive nature of the lung disease, pneumothorax often develops. Massive hemoptysis due to the erosion of enlarged and tortuous bronchial arteries can also occur. Many patients experience chronic sinusitis, which may exacerbate infection of the lower respiratory tract and may require repeated surgical drainage. Respiratory failure due to hypercapnia and hypoxemia eventually leads to death if lung transplantation is not performed.
Gastrointestinal Manifestations
Patients with cystic fibrosis have high energy requirements and poor ability to ingest adequate amounts of food because of dyspnea and fatigue. In addition, viscous pancreatic secretions obstruct pancreatic ducts, resulting in malabsorption of nutrients, especially fats and proteins as well as carbohydrates. This malabsorption results in malnutrition and failure to thrive that is manifested by lower than normal height and weight and deficiencies in the fat-soluble vitamins A, D, E, and K. Other gastrointestinal manifestations include bulky stools, intestinal obstruction, pancreatitis, biliary cirrhosis with portal hypertension, and gallbladder disease. Adults with cystic fibrosis may have impaired glucose tolerance, and diabetes mellitus often develops.
Other Manifestations
Other manifestations of cystic fibrosis include rheumatologic syndromes, osteoporosis, and the potential for salt loss with resultant dehydration, especially in hyperthermic conditions.6 Almost all males with cystic fibrosis are sterile because of obstructive azoospermia.
Management and Nursing Implications
Patients with cystic fibrosis require life-long treatment and management. Treatment goals focus on improvement in and prevention of further deterioration of lung function and improvement of nutritional status. Discussion of the overall therapeutic regimen for patients with cystic fibrosis is beyond the scope of this article. Here we focus on therapies specific to adults with the disease who are admitted to an ICU.
Adults with cystic fibrosis may be admitted to an ICU because of one of the many complications of the disease. Most are admitted because of respiratory failure during an acute exacerbation of cystic fibrosis, but even those who are admitted for other reasons are at grave risk for respiratory failure if they do not receive intensive and proactive medical and nursing care. Table 2 provides a nursing care plan for adults with cystic fibrosis who are admitted to an ICU.
Pulmonary Management
Maintenance of airway patency includes treatment of pulmonary infection, use of mucolytics and chest physiotherapy techniques for mobilization of secretions, and treatment of bronchospasm. Noninvasive mechanical ventilation may be successful when it can appropriately be used as an alternative to intubation. When intubation and mechanical ventilation are required for the management of hypoxemic and hypercapnic respiratory failure, an unsatisfactory outcome is likely unless the intubation and mechanical ventilation are done for a potentially reversible problem such as pneumothorax or hemoptysis.
Antibiotic Therapy
For patients with cystic fibrosis, antibiotic therapy is a cornerstone of lifelong treatment and is aimed at reducing the infectious burden in the airways (Table 3). During pulmonary exacerbations, the use of 2 antibiotics that are effective against P aeruginosa is recommended. Generally, a b-lactam is given in combination with an aminoglycoside, with specific drugs tailored to the results of bacterial cultures and tests for the antibiotic sensitivity of the causative organisms. Nursing care includes obtaining blood samples to determine and monitor drug levels and monitoring the patient for adverse reactions, including the nephrotoxic and ototoxic reactions associated with the use of aminoglycosides.
Respiratory epithelial cells in patients with cystic fibrosis are more susceptible to attachment of pseudomonal species than the cells in healthy persons are. This susceptibility results in chronic pseudomonal colonization and multiple antibiotic resistance after repeated courses of treatment with antibiotics. Patients who have antibiotic-resistant organisms must have appropriate infection control techniques instituted, including isolation. Adequate isolation is especially important for patients colonized with Burkholderia cepacia, an organism that can increase morbidity and mortality in cystic fibrosis.10
Airway Clearance
Chest physiotherapy has long been another cornerstone of cystic fibrosis therapy and must be part of each patient’s lifelong treatment plan. Many innovative techniques and devices have been developed to help patients be independent and compliant with chest physiotherapy. However, most of these techniques are not appropriate for patients in the ICU, especially if intubation is required.
Traditional chest physiotherapy includes percussion and vibration coupled with postural drainage. This technique is effective in clearing secretions for patients who can tolerate a 25° Trendelenberg position.11 An alternative to manual chest percussion and vibration that can be used even in patients receiving mechanical ventilation is high-frequency chest compression with the ThAIRapy Vest.11 The patient wears an inflatable vest that is attached via hoses to an air-pulse generator. Small volumes of gas are alternately injected and withdrawn from the vest at variable frequencies, simulating manual percussion and vibration and stimulating cough. In nonintubated patients with cystic fibrosis, use of the ThAIRapy Vest resulted in airway clearance and sputum production that were equal to or better than those achieved with traditional chest physiotherapy.11
Regardless of the method of chest physiotherapy chosen, each session takes at least 30 minutes, and the therapy may be required as often as every 1 to 4 hours, depending on the patient’s response and tolerance. If tolerated by the patient, postural drainage should be used in addition to either traditional or vest techniques. Patients may experience oxygen desaturation and increased work of breathing during chest physiotherapy. Mobilization of massive amounts of secretions or mucus plugs may precipitate acute hypoxemia and make frequent suctioning imperative.
Bronchoscopy may be necessary for patients who experience increased airway resistance associated with severe hypoxemia that cannot be explained or cannot be reversed with traditional methods. The endotracheal tube should be as large as possible in order to facilitate bronchoscopy and to decrease airway resistance. In patients who have been intubated for a prolonged period, the inner diameter of the tube used for intubation can become narrowed by an accumulation of secretions, a situation that may necessitate reintubation.
Nurses should always consider patients’ comfort during chest physiotherapy. Many patients with cystic fibrosis have chronic chest pain related to chronic lung infection and to chest physiotherapy regimens. Patients also may experience rib fracture because of osteoporosis. Analgesia and sedation are always part of the treatment plan for any patient receiving mechanical ventilation. Patients with cystic fibrosis should not be an exception. Additional consideration should be given to the fact that many of these patients are at the end of life. At the University of Virginia Health System in Charlottesville, the practitioners in the acute pain service are an integral part of the multidisciplinary team who provide care for patients with cystic fibrosis.
Use of Mucolytics
Clearance of secretions is enhanced by reducing the viscoelasticity of mucus. Systemic hydration is imperative. The use of acetylcysteine in patients with cystic fibrosis is not recommended because it is not efficacious and may induce bronchospasm.
The first new drug therapy for cystic fibrosis in 30 years was approved by the Food and Drug Administration in 1993 (Table 3). The drug, dornase alfa (Pulmozyme), can be given in aerosol form or via direct instillation into an endotracheal tube. It reduces the viscosity of secretions by degrading the extracellular DNA released from neutrophils in the inflamed airways of patients with cystic fibrosis.1 Treatment with dornase alfa reduces the number of respiratory infections and improves lung function.3
Use of Bronchodilators
Most patients with cystic fibrosis have a component of airway hyperresponsiveness, so bronchodilators (Table 3) are commonly used, especially before chest physiotherapy. b-Adrenergic agonists are the first-line bronchodilators, although some patients may have a paradoxical decrease in air flow with increased hyperinflation. The anticholinergic drug ipratroprium (Atrovent) may also be useful. Some patients may benefit from a combination of the 2 agents.
Use of Anti-inflammatory Agents
The chronic inflammation in cystic fibrosis causes continued lung destruction. Much of the current research on cystic fibrosis focuses on ways to decrease this inflammation. Although the long-term use of corticosteroids (Table 3) for the treatment of cystic fibrosis remains controversial, short courses of treatment with these drugs may be useful during acute exacerbations,12 especially in patients with wheezing, and may aid in reducing mucosal edema and bronchospasm. Patients should be monitored for adverse effects, including hyperglycemia, which must be treated aggressively to prevent further complications.
Mechanical Ventilation
Patients with cystic fibrosis may require intubation and mechanical ventilation for treatment of respiratory failure, massive hemoptysis, or pneumothorax or for procedures that require use of anesthesia. Patients with advanced cystic fibrosis may not tolerate the levels of sedation required for conscious sedation procedures because of respiratory depression and subsequent hypercapnia and may require intubation.
Hypoxemia and hypercapnia are difficult to reverse in patients with end-stage cystic fibrosis. Aggressive techniques for airway clearance become imperative, because intubation and mechanical ventilation make clearance of secretions from small airways more difficult.13 Most patients with cystic fibrosis who require mechanical ventilation for respiratory failure that is not precipitated by an acute and potentially reversible event have a deterioration of pulmonary function while receiving mechanical ventilation and cannot be weaned from the ventilator.13
Patients with cystic fibrosis who require mechanical ventilation may be even more susceptible than other patients who have such ventilation to ventilator-induced lung damage, pneumothorax, ventilator-acquired pneumonia, and respiratory muscle weakness and fatigue. Strategies to prevent nosocomial pneumonia14 should be used. An aggressive multidisciplinary approach, such as that suggested by Burns et al,15 is important for the management and weaning of patients who require long-term mechanical ventilation.
Published data on the optimal strategy for mechanical ventilation of patients with cystic fibrosis are lacking. The assist-control mode may contribute to air trapping with the development of intrinsic positive end-expiratory pressure and the potential for pneumothorax. Total positive end-expiratory pressure should be measured frequently when a volume mode is used.
Pressure-support ventilation (PSV) alone may not be appropriate initially because of the potential for decreases in tidal volume and subsequent hypoventilation that may occur with increases in airway resistance due to bronchospasm and secretions. Tidal volume and respiratory rate should be monitored frequently in patients treated with PSV, especially during activities such as chest physiotherapy. After the acute phase, PSV may allow diaphragmatic conditioning, which may facilitate weaning from mechanical ventilation.
Oxygenation and ventilation should be closely monitored. In our experience, as well as in that of Flume et al,16 patients with cystic fibrosis who have end-stage lung disease are often extremely hypercapnic, with Paco2 levels greater than 200 mm Hg. The medical team should be aware of each patient’s baseline arterial blood gas levels in order to avoid the use of excessively large tidal volumes or respiratory rates in an inappropriate attempt to establish “normal” arterial blood gas levels, which may contribute to the development of intrinsic positive end-expiratory pressure and barotrauma.
Noninvasive positive-pressure ventilation (NPPV) may be a practical option in some patients. Several investigators have used NPPV in cystic fibrosis patients with chronic respiratory failure. In one study,17 NPPV resulted in improved oxygenation and reduced Paco2 in 4 patients with cystic fibrosis who had acute respiratory failure. These patients continued to use NPPV for up to 18 months after they were discharged from the hospital.
NPPV may be useful on either an outpatient or an inpatient basis as a bridge to lung transplantation. NPPV is not appropriate for patients with cystic fibrosis who cannot protect their airway because of depressed mental status or who have massive secretions.
In the University of Virginia Health System, the initial mode for mechanical ventilation in patients with cystic fibrosis is a volume mode or the pressure-control mode. As a patient’s condition improves, the mode may be changed to PSV, with appropriate monitoring, in preparation for weaning. In many patients, NPPV is started immediately following extubation.
Pneumothorax develops in up to 20% of patients with cystic fibrosis at some time in their lives.18 Positive-pressure ventilation may increase the occurrence of barotrauma. Pneumothorax in patients with cystic fibrosis is treated with chest tube thoracostomy. For patients with persistent or repeated pneumothorax, a thoracic surgeon should be consulted for treatment options. Chemical pleurodesis may cause pleural scarring, which makes future lung transplantation more difficult. Major hemoptysis, defined as a loss of 240 mL or more of blood in a 24-hour period,13 develops in 1% of all cystic fibrosis patients each year.18 Hemoptysis, if severe, can result in occlusion of the airway and asphyxiation. Hemoptysis from an arterial source may require embolization of bronchial arteries.
Weaning from mechanical ventilation may not be possible for patients with end-stage cystic fibrosis. In many instances, unless mechanical ventilation is being used as a bridge to transplantation, patients and their families may desire cessation of mechanical ventilation even though death will result.
Nutritional Support
Adults with cystic fibrosis are at high risk for malnutrition because of increased energy needs, decreased nutritional intake during pulmonary exacerbations, and depression. Nutritional status often declines as pulmonary function deteriorates.19 By the time patients with cystic fibrosis are admitted to an ICU, they are at high nutritional risk, and nutritional support must be started as soon as possible. Because of the lack of clinical data, our nutritional support for patients with cystic fibrosis who are critically ill is based on our clinical practice in ambulatory patients with cystic fibrosis and on what is known about feeding critically ill patients. At the University of Virginia Health System, the nutrition support team is consulted as soon as a patient with cystic fibrosis is admitted to the ICU.
Enteral nutrition is the preferred route for feeding whenever possible. Patients are screened for contraindications to gastric feeding, such as a history of severe gastroesophageal reflux, nausea and vomiting, and gastroparesis. If contraindications are present, or if a patient cannot tolerate gastric feeding, postpyloric or jejunal feedings may be appropriate. In intubated patients, the use of orally rather than nasally placed feeding tubes may decrease the risk of sinusitis.20 Parenteral nutrition should be reserved for patients with a nonfunctional gastrointestinal tract.
Determination of energy requirements in patients with cystic fibrosis who are critically ill is difficult. Patients with cystic fibrosis generally have increased nutritional needs because of malabsorption related to pancreatic insufficiency, increased work of breathing, infection, and stress. Energy intakes of 130% to 150% of the recommended daily allowance for age have been recommended for ambulatory patients with this disease.21,22
Energy needs in patients with cystic fibrosis who are critically ill may be decreased by factors such as sedation. Overfeeding may exacerbate hyperglycemia and hypercapnia23; hypercapnia may delay weaning from mechanical ventilation. Underfeeding, on the other hand, may lead to respiratory muscle weakness, which may also hamper weaning efforts. The factors that affect the energy needs of each patient must be carefully evaluated. Gross overfeeding should be avoided, but energy intake should not be restricted to treat hypercapnia or hyperglycemia. Protein intake of 2 times (200%) the recommended daily allowance for age has been recommended.21
Replacement of pancreatic enzymes must be continued during enteral feeding. Powdered enzymes can be mixed with the tube feeding formula. If tube feedings are delivered into the stomach, gastric acid suppression may minimize breakdown of enzymes by gastric acid. Therapies such as postural drainage and chest physiotherapy preclude keeping the head of the bed elevated in these patients. Tube feedings should be temporarily stopped at least 30 to 60 minutes before these therapies. In order to ensure that the prescribed nutrients are delivered, either an intermittent or a nocturnal cycle for delivering tube feedings may be prudent in patients with cystic fibrosis.
Patients with cystic fibrosis should be regularly evaluated for gastrointestinal intolerance. Diarrhea may be caused by medications, the development of Clostridium difficile infection, or malabsorption. Hyperglycemia is common because of diabetes, corticosteroid therapy, and stress. Blood glucose levels must be controlled if patients are to optimally use supplied nutrients.
Lung Transplantation
Although research into genetic therapy is under way in hopes of finding a cure for cystic fibrosis, currently, the only option for patients with end-stage disease is bilateral lung transplantation. In 1998, survival after transplantation in patients with cystic fibrosis was 56% at 3 years and 48% at 5 years.24 The time for referral for transplantation remains difficult to define, partly because the waiting period for cadaveric lungs is usually at least 2 years. Patients are usually referred when their forced expiratory volume in 1 second is less than 30% of predicted.25 Because of the scarcity of cadaveric lungs, more transplant centers are performing living-donor lobar transplants.26
Social and Psychological Issues
Caring for adults with cystic fibrosis in the critical care setting is similar to caring for other chronically ill patients. The difference is that the patients with cystic fibrosis are usually relatively young and may be at or near the end of their lives. A few patients with cystic fibrosis who are treated with mechanical ventilation for specific, self-limiting reasons may do well and may be extubated fairly quickly. Most patients with cystic fibrosis who require mechanical ventilation have more prolonged courses, either as they await lung transplantation or during repeated admissions for those with end-stage disease who are not candidates for transplantation.
Establishing good patterns of communication between the healthcare team and patients and patients’ families early in the ICU stay is imperative. If a patient has been treated by a team of cystic fibrosis experts, the team should be consulted about the patient’s previous course and wishes regarding intubation and life support. All available resources such as social workers, hospice personnel, and clergy should be used to assist in planning and decision making.
Conclusion
Care of patients with cystic fibrosis who are admitted to an ICU requires the proactive approach of a multidisciplinary team. Treatment priorities include treating airway infection and inflammation, promoting airway clearance, and weaning from mechanical ventilation. The emotional aspects of caring for these patients and their families, especially when end-of-life decisions are made, cannot be overlooked. Even as research continues into new therapy for patients with cystic fibrosis, and gene therapy gives the hope of an eventual cure, critical care nurses can have a positive impact on the lives of cystic fibrosis patients and the patients’ families.
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