COPD Treatment and Bronchodilators PDF

The main objective in treating patients with hypoxemia and hypercapnia is to give sufficient oxygen to improve oxygenation. Patients with COPD who require oxygen may have respiratory failure that is caused primarily by a ventilation–perfusion mismatch. These patients respond to oxygen therapy and...

The main objective in treating patients with hypoxemia and hypercapnia is to give sufficient oxygen to improve oxygenation. Patients with COPD who require oxygen may have respiratory failure that is caused primarily by a ventilation–perfusion mismatch. These patients respond to oxygen therapy and should be treated to keep the resting oxygen saturation at or above 90%, which is associated with a PaO2 of 60 mm Hg or higher (GOLD, 2019). Nursing assessments of a patient with COPD on supplemental oxygen must include monitoring the respiratory rate and the oxygen saturation as measured by pulse oximetry (SpO2) so that the patient has an adequate oxygen saturation (90%) on the lowest liter flow of oxygen (GOLD, 2019). Administering too much oxygen can result in the retention of carbon dioxide. The high O2 levels can then suppress CO2 chemoreceptors, which in turn would depress the respiratory drive and disrupt ventilation–perfusion balance (Kacmarek et al., 2017). The resulting increased O2 tension in the alveoli causes a ventilation–perfusion mismatch that presents as hypercapnia. Monitoring and assessment are essential in the care of patients with COPD on supplemental oxygen due to complications of oxygen supplementation. Although pulse oximetry is helpful in assessing response to oxygen therapy, it does not assess PaCO2 levels. A SaO2 of 88% or less warrants further evaluation with arterial blood gas analysis (GOLD, 2019). The nurse must evaluate for other factors and medications which could further decrease the respiratory drive—neurologic impairment, fluid and electrolyte issues, and opioids or sedatives. Quality and Safety Nursing Alert Oxygen therapy is variable in patients with COPD; its aim in COPD is to achieve an acceptable oxygen level without a fall in the pH (increasing hypercapnia). Pharmacologic Therapy Medication regimens used to manage COPD are based on disease severity. For grade I (mild) COPD, a short-acting bronchodilator may be prescribed. For grade II or III (moderate or severe) COPD, a short-acting bronchodilator and regular treatment with one or more long-acting bronchodilators may be used. For grade III or IV (severe or very severe) COPD, medication therapy includes regular treatment with long-acting bronchodilators and/or inhaled corticosteroids (ICSs) for repeated exacerbations. Bronchodilators 1735 Bronchodilators are key for symptom management in stable COPD (GOLD, 2019). The choice of bronchodilator depends on availability and individual response in terms of symptom relief and side effects. Long-acting bronchodilators are more convenient for patients to use, and combining bronchodilators with different durations of action and different mechanisms may optimize symptom management (GOLD, 2019). Long-acting bronchodilators are typically used for maintenance treatment for long-term symptom control. Short-acting bronchodilators are usually used for acute management of symptomatic flairs. Even patients who do not show a significant response to a short-acting bronchodilator test may benefit symptomatically from long-term bronchodilator treatment. Bronchodilators relieve bronchospasm by improving expiratory flow through widening of the airways and promoting lung emptying with each breath. These medications alter smooth muscle tone and reduce airway obstruction by allowing increased oxygen distribution throughout the lungs and improving alveolar ventilation. Although regular use of bronchodilators that act primarily on the airway smooth muscle does not modify the decline of function or the prognosis of COPD, their use is central in the management of COPD (GOLD, 2019). These agents can be delivered through a pressurized metered-dose inhaler (pMDI), a dry-powder inhaler (DPI), by a small-volume nebulizer (SVN), or via the oral route in pill or liquid form. Bronchodilators are often given regularly throughout the day as well as on an as-needed basis. They may also be used prophylactically to prevent breathlessness by having the patient use them before participating in or completing an activity, such as eating or walking. Several devices are available to deliver medication via the inhaled route. These may be categorized as pMDIs, DPIs, or SVNs, as noted previously (Cairo, 2018; Gregory, Elliott, & Dunne, 2013). The choice of an inhaler device will depend on availability, cost, prescribing provider, insurance coverage, and the skills and ability of the patient (GOLD, 2019). Key aspects of each are described in Table 20-3. Both pMDIs and DPIs are small handheld devices that may be carried in a pocket or purse (Cairo, 2018; D’Urzo, Chapman, Donohue, et al., 2019). Attention to effective drug delivery and training in proper inhaler technique is essential when using a pMDI or DPI. A respiratory therapist is an excellent health care provider to consult on appropriate inhaler technique. Pressurized metered-dose inhalers (pMDIs) include conventional pMDIs or breath- actuated pMDIs; these may also feature spacer or valved-holding chambers (VHCs). They are pressurized devices that contain aerosolized powder of medications. A precise amount of medication is released with each activation of the pMDI canister. A spacer or VHC may also be indicated to enhance deposition of the medication in the lung and help the patient coordinate activation of the pMDI with inspiration. Spacers come in several designs, but 1736 all are attached to the pMDI and have a mouthpiece on the opposite end (Fig. 20-5). All pMDIs are designed so that they require coordination between the patient’s inspiration and the mechanics of the inhaler. In contrast, dry-powder inhalers (DPIs) (see Fig. 20-5) rely solely on the patient’s inspiration for medication delivery. While DPIs still require the user to press a lever or button to dispense the medication, these inhalers do not require the coordination necessary to administer pMDIs. Because of the significant relationship between poor inhaler technique and lack of symptom control, issues that could affect proper inhaler use must be considered when assessing the effectiveness of these medications (GOLD, 2019). Conditions such as decreased hand–inhalation coordination, insufficient hand strength, and the inability to generate a sufficient inspiratory flow could impair the delivery of the medication, and thus, impair symptom control (D’Urzo et al., 2019). For example, patients with decreased hand–inhalation coordination could fail to exhale prior to administering pMDIs, which would prevent them from inhaling the proper amount of the medication. While DPIs minimize the need for hand–inhalation coordination, patients with severe COPD may not have the ability to generate a sufficient inspiratory flow necessary to deliver the proper dose (D’Urzo et al., 2019). 1737 TABLE 20-3 Aerosol Delivery Devices 1738 Devices/Drugs Optimal Technique Therapeutic Issues Pressurized Actuationa during a slow (30 Slow inhalation and coordination of metered-dose L/min or 3–5 s) deep actuation may be difficult for some inhaler inhalation, followed by 10-s patients. Patients may incorrectly (pMDI) breath-hold stop inhalation at actuation. Beta-2- Deposition of 50–80% of actuated adrenergic dose in the oropharynx. Mouth agonists washing and spitting is effective in Corticosteroids reducing the amount of drug Anticholinergics swallowed and absorbed systemically Breath-actuated Tight seal around mouthpiece May be particularly useful for patients pMDI and slightly more rapid unable to coordinate inhalation and Beta-2- inhalation than standard actuation. May also be useful for adrenergic pMDI (see above) followed older patients. Patients may agonists by 10-s breath-hold incorrectly stop inhalation at actuation. Cannot be used with currently available spacer/valved- holding chamber (VHC) devices Spacer or VHC Slow (30 L/min or 3–5 s) deep Indicated for patients who have (Note—this is inhalation, followed by 10-s difficulty performing adequate pMDI an accessory breath-hold immediately technique. May be bulky. Simple to a pMDI) following actuation. Actuate tubes do not obviate coordinating only once into spacer/VHC actuation and inhalation. VHCs are per inhalation. Rinse plastic preferred. Spacers or VHCs may VHCs once a month with increase delivery of inhalational low concentration of liquid corticosteroids to the lungs household dishwashing detergent (1:5000 or 1–2 drops per cup of water) and let drip dry Dry-powder Rapid (1–2 s) deep inhalation. Dose is lost if patient exhales through inhaler (DPI) Minimally effective device after actuating. Delivery may Beta-2- inspiratory flow is device be greater or lesser than pMDIs, adrenergic dependent depending on device and technique. agonists Delivery is more flow dependent in Corticosteroids devices with highest internal Anticholinergics resistance. Rapid inhalation promotes greater deposition in larger central airways. Mouth washing and spitting are effective in reducing amount of drug swallowed and absorbed systemically Small-volume Slow tidal breathing with Less dependent on patient’s nebulizer occasional deep breaths. coordination and cooperation. (SVN) Tightly fitting facemask for May be expensive, time-consuming, Beta-2- those unable to use and bulky; output depends on device adrenergic mouthpiece and operating parameters (fill agonists volume, driving gas flow); 1739 Corticosteroids internebulizer and intranebulizer Anticholinergics output variances are significant. The use of a facemask reduces delivery to lungs by 50%. Choice of delivery system depends on resources, availability, and clinical judgment of clinician caring for patient. There is potential for infections if device is not cleaned properly aActuationrefers to release of dose of medication with inhalation. Adapted from Cairo, J. M. (2018). Mosby’s respiratory care equipment (10th ed.). St. Louis, MO: Elsevier Mosby. Figure 20-5 A. Examples of pressurized metered-dose inhalers (pMDIs) and spacers and a dry-powder inhaler (DPI). B. A pressurized metered-dose inhaler and spacer in use. The small-volume nebulizer (SVN) is a handheld apparatus that is easier to use than a pMDI or a DPI but lacks the convenience of these inhalers as it requires a power source in order to operate. Common SVNs include single-use pneumatic jet nebulizers with reservoir tubes, which are most commonly used in hospitals, and electronic nebulizers, which may be used in the home-based setting (Gregory et al., 2013). SVNs are commonly prescribed when patients are challenged with being able to administer their medications through either a pMDI or a DPI; some reasons why this might happen have been described previously (Cairo, 2018). The SVN may also be a preferred option to other inhalers because the nebulized particles in an SVN are smaller and can better penetrate the airways. Diaphragmatic breathing (see later discussion under “Breathing Retraining”) is a helpful technique to prepare for proper use of the SVN. 1740