13.Basic Knowledge and Environmental Considerations of Risk Factors and Avoidance of Aspiration

Explanation

It is important to ensure safety when working with dysphagic patients.

Patients with dysphagia might choke or aspirate at any time, which puts their lives at risk. To avoid such risks, we need to identify risk factors in each patient with dysphagia and take a preventive approach. In this module, we cover the basic knowledge and environmental considerations necessary to identify risks.

Explanation

Identifying individual risk factors associated with dysphagia is the most important step in risk avoidance. Risk factors can be broadly divided into factors individual to each patient with dysphagia and related environmental factors.

Explanation

When patients with acute cerebrovascular disease have a Japan Coma Scale (JCS) score for impairment of consciousness in the double digits or higher, oral feeding should be stopped. When they have mild impairment (ie. somnolence) or a fluctuating consciousness level, risk should be minimized by stopping oral feeding until their consciousness level stabilizes.

Explanation

To ensure safe oral feeding, it is important to accurately evaluate swallowing function by understanding the patient's general condition and conducting a medical interview and examination that includes, for example, screening tests, videofluoroscopy (VF), and videoendoscopy (VE). Selection of suitable feeding conditions and environmental adjustment based on appropriate evaluation will lead the risk avoidance.

Explanation

Poor respiratory status due to issues such as expectoration or wheezing reduces patients' ability to expel sputum and can increase the likelihood of aspiration. Also, in patients with a tracheostomy tube, certain factors are of concern due to their potential to negatively impact swallowing function. These factors include ①restricted laryngeal elevation, ②compression of the cervical esophagus by the tracheostomy tube cuff, ③an increased sensory threshold in the airway,④inability to maintain subglottic pressure, and ⑤increased reflex thresholds for laryngeal closure.

Explanation

The cough reflex is a biological protective mechanism at the vocal cords that the body uses to expel foreign bodies that have entered the airway. Some people, such as people with dysphagia and the elderly, have a weakened or absent cough reflex. They may aspirate without coughing or choking (ie. silent aspiration), and they must be carefully monitored for symptoms associated with aspiration, such as respiratory distress and cyanosis.

Explanation

Communication disorders that are caused by higher brain dysfunction (impairment of mental function including sensory, memory, learning, thinking, decision-making, and emotional function) can effect a patient's risk, by reducing food intake and posing risks of choking and aspiration.

Explanation

Unnecessary fasting can cause disuse syndrome. Undernutrition causes muscle mass to decrease, and the resulting muscle weakness causes dysphagia. Undernutrition can also reduce immunity. Dehydration reduces salivary function, which negatively impacts oral hygiene and slows the passage of food boluses into the pharynx.

Explanation

Aspiration of saliva or food contaminated with bacteria increases the risk of pneumonia. Aspiration of saliva occurs during nocturnal sleep. Contamination in the oral cavity leads to issues such as tooth decay, periodontal disease (gingivitis and pyorrhea), and stomatitis. Periodontal disease can cause tooth loss, which hinders the formation of food boluses by mastication. Patients who are being tube fed or have a gastric fistula (PEG) are at risk of reduced salivary function due to the low frequency with which they use their mouth. This can result in proliferation of intraoral bacteria.

Explanation

1. Dysphagia diet: Offering an appropriate dysphagia diet that is appropriate for the patient's swallowing function is critical for preventing aspiration.

2. Eating position: Ensuring that the patient's eating position is appropriate for their swallowing function is critical for effective swallowing and for preventing aspiration and choking.

3. Direct swallowing training and techniques for mealtime assistance: Risk can be affected by direct swallowing training using food and the skill of the person providing mealtime assistance.

Explanation

All patients judged to have oral feeding difficulties should receive alternative nutrition, regardless of the cause of their dysphagia. Types of alternative nutrition include tube feeding and total parenteral nutrition (TPN), but all methods carry risks. Accidental tube insertion into the airway or delivery of liquids into the airway can occur with nasogastric (NG) tubes and IOC (Intermittent Oral Catheterization), and diarrhea can occur at a high infusion rate with PEG tubes.

TPN, another alternative nutrition method, poses risks such as sepsis associated with catheter infection, electrolyte imbalance, and blood loss associated with self-extubation.

Explanation

Reduction in swallowing function due to adverse effects of drug can also pose risks of aspiration and choking. Drugs that can reduce consciousness level or alertness, reduce salivation, impair motor function, or damage the mucosa must be administered with care.

Explanation

A suction machine should always be available during meal ingestion by patients with dysphagia to ensure that suctioning is always possible. An emergency cart should be made available for emergency situations.

References

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2. Nishiwaki K, et al.: Identification of a simple screening tool for dysphagia in patients with stroke using factor analysis of multiple dysphagia variables. J Rehabil Med. Jul; 37(4): 247-51, 2005.
3. Toharu H, et al.: A flowchart for evaluation of dysphagia without videography. Jpn J Dysphagia Rehabil. 6(2): 196-206, 2002.
4. Mizuno M, Saitoh E: Screening of dysphagia by X-ray: Comparing the findings of X-ray photos taken before and after swallowing contrast medium with those of videofluorography. Jpn J Rehabil Med. 37(10): 669-675, 2000.
5. Hegland KW, et al.: Comparison of two methods for inducing reflex cough in patients with Parkinson's disease, with and without dysphagia. Dysphagia. Feb; 31(1): 66-73.2016.
6. Kagaya H: Pulmonary rehabilitation in patients with dysphagia. J Jp Soc Resp Care Rehab. 21(1): 9-12.2011.
7. Tanaka T, et al.: Early pulmonary complications after videofluoroscopic examination of swallowing. Jpn J Rehabil Med. 47(5): 320-323, 2010.
8. Seidl RO, et al.: The influence of tracheotomy tubes on the swallowing frequency in neurogenic dysphagia. Otolaryngol Head Neck Surg.132: 484-6, 2005.
9. Feldman SA, et al.: Disturbance of swallowing after tracheostomy. Lancet.1: 954-5, 1966.
10. Bonanno PC. Swallowing dysfunction after tracheostomy. Ann Surg.174: 29-33, 1971.
11. Shaker R, et al.: Deglutitive aspiration in patients with tracheostomy: Effect of tracheostomy on the duration of vocal cord closure. Gastroenterology.108: 1357-60, 1995.