Early Respiratory Insufficiency in the ALS Patient: A Case Study
Copyright American Association of Neurosurgical Nurses Aug 2005
Story from REDNOVA NEWS: http://www.rednova.com/news/display/?id=214346
Published: 2022/08/20 03:00:47 CDT
08-20-05
Abstract: Respiratory insufficiency is a problem
that develops in nearly all people diagnosed with amyotrophic lateral sclerosis
(ALS). Noninvasive positive pressure ventilation (NIPPV) is the treatment of
choice for ALS patients with respiratory insufficiency. Forced vital capacity
(FVC) is the test most commonly used to qualify ALS patients for NIPPV; however,
some research suggests FVC may not be the best tool to measure early respiratory
insufficiency in all patients with ALS. This case study introduces an ALS patient
who had normal FVC results, symptoms of respiratory insufficiency, and abnormal
nocturnal oximetry. After NIPPV initiation, the patient reported improved sleep
and less daytime fatigue, which he associated with the start of NIPPV treatment.
Amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease) is a fatal, progressive neuromuscular disease that causes motor neuron degeneration that results in weakness and eventual paralysis of all voluntary muscles, including the muscles used for respiration. In ALS, motor neurons that innervate the muscles used for inspiration die, leading to respiratory insufficiency and eventual respiratory failure. The most common cause of death for ALS patients is respiratory failure due to weakness of the diaphragm and intercostal muscles. Symptoms of respiratory insufficiency include orthopnea, dyspnea, daytime fatigue, sleep disturbances, and morning headaches.
Neuromuscular respiratory insufficiency in ALS patients typically is measured with a pulmonary function test to obtain forced vital capacity (FVC). The FVC measures expiratory muscle strength. Other screening tools to measure respiratory insufficiency in the ALS population include maximum inspiratory pressure (MIP), arterial blood gases (ABGs), and nocturnal oximetry.
Noninvasive positive-pressure ventilation (NIPPV) is the treatment of choice for ALS patients with respiratory symptoms. This device is covered under most health insurance policies (including Medicare) if the FVC is lower than 50% of the predicted value; if the MIP is lower than 60 cm H2O; or if the PaCO^sub 2^, as measured by ABGs, is higher than 45 mmHg. NIPPV also is covered by insurance if nocturnal oximetry is lower than 88% for 5 or more continuous minutes. Source: (Cigna Healthcare Medicare Administration, 2004).
While the FVC is the tool that often is used to qualify ALS patients for NIPPV, FVC alone may not adequately measure early respiratory insufficiency in the ALS population. In their study of 20 ALS patients who had a predicted FVC between 70%-100%, Jackson et al. (2001) found that FVC correlated poorly with respiratory symptoms. Lechtzin Rothstein, Clawson, Diete and Weiner (2002) reported that the FVC can remain normal despite substantial inspiratory muscle weakness. They also found that patients with significant bulbar symptoms may have falsely low FVC values because it may be difficult for them to achieve a tight seal on the mouthpiece. Varrato et al. (2001) suggested the FVC be measured in both sitting and lying positions, with the supine FVC being a more accurate measurement of diaphragmatic weakness. Given the nature of ALS, however, not all patients can be placed on a hospital bed or table because of their immobility.
Other measurement tools to assess respiratory insufficiency in the ALS population are needed. This article presents a case study of an ALS patient with symptoms of respiratory insufficiency and an abnormal nocturnal oximetry even though his FVC results are within normal limits.
Case Study: Robert Land (not his
real name) is a 53-year-old male who developed a left foot drop in August 2001,
and was diagnosed with ALS in September 2002. Mr. Land first was seen at the
ALS Center on October 10,2002. An active smoker, his medical history included
ruptured discs at the 4th and 5th lumbar vertebrae, ulcerative colitis, and
occasional sinus complaints. Mr. Land did not take any prescription medications.
He stood 5 ft, 10 in tall, and weighed 242 lbs. Mr. Land presented with the
following neurologic findings upon his first visit: mild weakness of his left
hand and arm, bilateral foot drop, and mild dysarthria and dysphagia. Mr. Land
had work- and insurance-related concerns, and his wife and daughter were visibly
distraught and had many questions about his ALS diagnosis. The only respiratory
symptom at this first visit was intermittent orthopnea, which he reported as
a relatively new symptom that was not problematic.
The FVC is considered normal if it is higher than 79% of the predicted result.
The predicted result is a percentage of the value that would be expected in
an individual with the same age, height, weight, and gender who has no other
contributing variables. The focus of Mr. Land's first three visits involved
assessing functional changes. Tools and techniques to help with these changes
were implemented, such as bilateral ankle braces, a diet change to soft foods,
and incorporation of swallowing strategies. The emotional aspects of his diagnosis
and his health insurance and financial concerns also were addressed. Mr. Land's
fourth visit on June 19, 2003, revealed a drop in his FVC, though it still was
not low enough to qualify for NIPPV. He reported dyspnea on exertion (DOE),
orthopnea, frequent nighttime awakenings, and morning headaches. Given his weight,
age, active smoking status, and the stress of dealing with ALS, there was concern
that Mr. Land's respiratory symptoms could be cardiac related. He was counseled
to stop smoking, but was not counseled about weight loss, given that ALS patients
often develop significant weight loss due to muscle atrophy. Mr. Land was told
to see a cardiologist and was sent home with a nocturnal oximeter to continuously
measure his oxygen saturation for 1 night as he slept.
During the next 4 weeks, Mr. Land had a chest X ray, a dipyridamole stress test, and an echocardiogram. The results of these tests did not reveal a cardiac cause for his respiratory symptoms. The results of Mr. Land's nocturnal oximetry test, however, qualified him to begin MPPV on June 21,2003. The nocturnal oximetry test was repeated while he was on NIPPV 2 months later, and results revealed significant improvement. In addition, Mr. Land reported improved sleep, less daytime fatigue, and cessation of his morning headaches. During subsequent visits (after August 14, 2022), Mr. Land continued to describe DOE, orthopnea, and daytime fatigue, but he also reported improved sleep, less daytime fatigue, and no morning headaches, which he attributes to use of NIPPV at night.
Soon after being diagnosed with ALS, Mr. Land described having intermittent orthopnea, a symptom of respiratory insufficiency, which was occurring despite his normal FVC results. Within 8 months, his respiratory muscle weakness progressed to cause more significant symptoms. The most common tool to assess for neuromuscular respiratory weakness, the FVC, did not reflect the severity of his symptoms. Because of his nocturnal oximetry results, he did not have to wait the 4 months it takes for an FVC to fall below 50% predicted to begin using NTPPV. He received immediate relief of his respiratory symptoms upon NTPPV initiation and was able to tolerate more daytime activities because he was not as fatigued.
Mr. Land's case represents an unusual presentation of respiratory insufficiency in ALS. Typically, ALS patients have increasing respiratory symptoms and a proportional decline in FVC, which justifies use of NIPPV to support their weakened respiratory muscles as their symptoms worsen. Mr. Land's FVC remained above range for NIPPV for at least 4 months after he reported functionally impairing respiratory symptoms. Although his FVC was higher than the 50% predicted, his nocturnal oximetry report illustrates he was experiencing hypoventilation during sleep. Hypoventilation due to neuromuscular respiratory weakness can cause carbon dioxide retention, daytime fatigue, decreased stamina, and eventual respiratory failure.
Nurses who work with patients with neurological disorders that cause respiratory muscle weakness need to be familiar with symptoms of respiratory insufficiency and the tools that measure it. Every visit should include a thorough respiratory assessment that features questions about respiratory symptoms, such as DOE, orthopnea, difficulty sleeping at night, morning headaches, and daytime fatigue. The visit also should include a physical examination to check for signs of paradoxical breathing and use of accessory muscles. Patients may not be forthcoming about symptoms because they may attribute fatigue and sleeping difficulties to factors other than respiratory insufficiency, or they may not want to admit their illness is progressing. The tools that measure respiratory function are revealing, and prompt more detailed questioning of the patient. Conversely, as in the case of Mr. Land, symptoms may not correlate with the results of the usual testing measures. Healthcare \professionals need to be aware of-and have available-a variety of tools that measure respiratory function.
Some recent reports find that introducing NIPPV earlier than the current parameters dictate as mentioned below in ALS patients may extend their survival. This strategy entails initiating NIPPV before the conventional tools indicate the need for respiratory support. Kleopa, Sherman, Neal, Romano, and Heiman-Patterson (1999), Sivak, Shefner, Mitsumoto, and Taft (2001), and Bach (2002) report that patients with ALS who use NIPPV for more than 4 hours per day, and those who begin NIPPV earlier than the current measure parameters dictate, survive longer than those who refuse NIPPV or those who use it for fewer than 4 hours per day. Other authors emphasize that better NIPPV compliance is achieved with earlier NIPPV initiation (Jackson et al., 2001; Pinto, de Carvalho, Evangelista, Lopes, & Sales-Luis, 2003; Oppenheimer, 2003). Initiating NIPPV before meeting CMS guidelines, however, most likely means ALS patients will be responsible for renting or purchasing the device; this may not be economically feasible for all ALS patients.
The symptoms caused by respiratory muscle weakness are some of the most debilitating symptoms experienced by ALS patients. Respiratory failure causes death in ALS. Because NIPPV can minimize these symptoms and possibly extend life, it is important to offer this intervention to ALS patients. Nurses play an essential role in this process, which includes educating patients and their families about NIPPVs purpose and benefits, and overall treatment goals of the patient care team.
ALS is a fatal, progressive neuromuscular disorder that involves respiratory muscle weakness and eventual respiratory failure. NIPPV is the treatment of choice for respiratory insufficiency associated with ALS. FVC is the tool that is used most often to qualify ALS patients for NIPPV, but recent research suggests this might not be the most effective means to measure early respiratory insufficiency in all ALS patients. A newly diagnosed ALS patient's nocturnal oximetry revealed significant periods of oxygen desaturation during 1 night's sleep. NIPPV was initiated, and the patient reported immediate improvement in sleep, less daytime fatigue, and no morning headaches. Nocturnal oximetry appears to be a more sensitive tool than FVC for measuring this patient's respiratory status.
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Questions or comments about this article may be directed to Gail Houseman, MSN RN APRN, by e-mail at gail@alsphiladelphia.org . She is a clinical nurse specialist and a regional nurse coordinator for the Greater Philadelphia Chapter of the ALS Association, Ambler, PA.
Mary Kelley, MSN RN APRN, is a nurse practitioner and the nurse coordinator for the ALS Center at the Penn Neurological Institute of the University of Pennsylvania, Philadelphia, PA.