When treating patients with dysphagia, it is important to evaluate the whole patient. The patient, the family, and the medical team consult the speech-language pathologist for the best clinical judgment on patient prognosis. This requires understanding the potential effects of the patient’s medication, and the significance of their lab results as they relate to their disease process (Langmore, 1998; Langmore 2002). It is important to note that swallow function is not evaluated in isolation, nor is it based on any one lab value. Using the finding from only a single test represents a gross oversimplification of clinical practice. Many factors enter into assessing and treating illnesses, and the results from a single laboratory test are of limited use if they are not combined with the clinical signs and symptoms that the patient exhibits (Altman et al. 2010; Whitney, Cataldo, & Rolfes, 1998; Mills & Ashford, 2008).
Lab values can help shed light on the patient’s underlying health status and their ability to fight infections. It is not the clinician’s job to diagnose disease, rather integrate the information from the medical chart to aid in the development of a treatment plan that includes a holistic approach to evaluating patients (Mills & Ashford, 2008; Burtis & Ashwood, 1999; McPherson & Pincus, 2011). Laboratory assessment is one of the most important areas in the evaluation of a patient’s health status.
To begin a discussion on laboratory tests, it is important to note that normal reference ranges may vary between laboratories. For complete and absolute comparison, the results must come from the same lab. There can be some comparisons across laboratories, but the clinicians should keep in mind that slight variations can exist.
Adequate nutrition is essential for the immune system to function well. It is also important to note that malnutrition is a condition found in patients who are at risk for aspiration. Bouchard (2009) found that 80% of patients with aspiration pneumonia were also malnourished. The nutritional lab values that are important are albumin, prealbumin, and body mass index (BMI).
Albumin and Prealbumin Definitions
Albumin is the most common protein found in the blood. It provides the body with the protein needed to both maintain growth and repair tissues. It is frequently used to help evaluate a patient’s overall health status.
Prealbumin is a lab value that is also frequently used to monitor nutritional status. It is a protein that is made by the liver and can also be an indicator of protein status. Prealbumin levels reflect the synthesis capacity of the liver, and is found dramatically decreased in malnutrition and other conditions.
• Hydration status
• Medications, like corticosteroids, can increase PAB and lower ALB.
• CHF can increase plasma volume and lower PAB and ALB.
• Renal and liver dysfunction/disease
• Pregnancy/bedridden state
• Inflammatory processes
(Banh, 2006; Bernstein, Kreutzer, & Steffen, 2014)
“It is important to realize that an increase in Prealbumin or Albumin level may be the result of improvement in overall clinical status, and not necessarily due to improved nutritional status” (Banh, 2006, p. 46). These levels alone are not used to diagnose malnutrition, but are used as a part of a battery of exams and clinical data used to determine a patient’s nutritional status (Murray, 2010).
Body Mass Index (BMI) is a person’s weight in kilograms divided by the square of height in meters. A high BMI can be an indicator of high body fat. BMI can be used to screen for weight categories that may lead to health problems, but it is not a diagnostic of the body fatness or health of an individual (CDC, 2015).
• Body Mass Index (BMI)
• Helps to measure nutrition over time
• In ALS patients, BMI can be a predictor of survival (Ngo, Steyn, & McCombe, 2014)
BMI Calculations
• How to calculate BMI:
Equation: Pounds × 703/height (inches) squared Weight (kilograms)/height (meters) squared
Part 2. Blood Chemistry Lab Values
Blood is the carrier of all nutrients, oxygen, hormones, electrolytes, and cellular waste products. Blood chemistry tests are designed to detect abnormalities within the blood. Every system of the body is dependent on blood for life sustenance. All blood chemistry labs are important, not just the three listed here. Arterial blood gas, white blood cells, and red blood cells.
An arterial blood gas (ABG) test measures the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery. This test is used to check how well the lungs are able to move oxygen into the blood, and remove carbon dioxide from the blood. As blood passes through the lungs, oxygen moves into the blood, while carbon dioxide moves out of the blood into the lungs. An ABG test uses blood drawn from an artery, where the oxygen and carbon dioxide levels can be measured before they enter body tissues (Larkin & Zimmanck, 2015).
Samples of arterial blood are used to:
• Monitor status of critically ill patients, typically those with tracheostomies or patients recently weaned from vents
• Modify respiratory interventions
• Assess acid-base balance, oxygenation, and ventilation
• Pa: Partial pressure is the amount of pressure exerted by each gas in a mixture of gasses.
• PaO2: (Partial pressure of oxygen) Measures the pressure of oxygen dissolved in the blood, and how well oxygen is able to move from the airspace of the lungs into the bloodstream.
• PaCO2: (Partial pressure of carbon dioxide) Measures the pressure of carbon dioxide dissolved in the blood, and how well carbon dioxide is able to move out of the body.
• HCO3: Bicarbonate is a chemical (buffer) that keeps the pH of blood from becoming too acidic or too basic.
• pH: The pH measures hydrogen ions (H+) in blood. The pH of blood is usually between 7.35 and 7.45. A pH of less than 7.0 is called acid and a pH greater than 7.0 is called basic (alkaline). Blood is slightly basic.
• Combined Pa: Partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2) is the force needed to transport O2 and CO2 in the blood.
The WBC represents the total number of leukocytes present in a measure of blood. There are five different types of leukocytes (lymphocytes, neutrophils, basophils, eosinophils, and monocytes) that all have differing functions as they relate to the immune system (Mills & Ashford, 2008). Alterations in these levels can provide valuable information about the dysphagia patient’s immune system and ability to fight infections.
• The value indicates the number of white blood cells in the body.
• WBCs (leukocytes) are an important part of the immune system.
• These cells help fight infections by attacking bacteria, viruses, and germs that invade the body.
• White blood cells originate in the bone marrow and circulate throughout the bloodstream.
• This value can help to detect the presence of infection or inflammation.
As stated earlier, there are five major types of white blood cells: lymphocytes, neutrophils, eosinophils, monocytes, and basophils.
Lymphocytes. Lymphocytes are made up of B cells and T cells.
• B cells = effector cells that are activated by antigens to fight an active infection
• T cells = memory cells have been in the body long enough to act quickly if reinfection occurs
• B lymphocytes and T lymphocytes work together to fight infection.
Neutrophils. Neutrophils play a very important role in dysphagia (Mills & Ashford 2008), and are the first responders to acute infections, and present in the oral cavity to trap and destroy pathogens. Neutrophils lead the immune system’s response making up of 55% to 70% of white blood cells.
• Neutrophils = 40% to 70% of WBC
• >70% could indicate bacterial infection
• Absolute Neutrophil Count (ANC)
• Altered with immunosuppression
• The field of speech-language pathology needs to reinforce the issue of colonization of the oral cavity by pathogens (Ortega et al., 2015)
• Destroy invading germs like viruses, bacteria, or parasites, and play an important role in the inflammatory allergic responses
Monocytes
• Fight infection, help remove damaged tissue, and destroy cancer cells
Basophils
• Prevent blood clotting and mediates allergic reactions; Basophils are also thought to play a role in causing the body to produce the antibody called immunoglobulin E.
• Basophils contain heparin, a naturally occurring blood-thinning substance.
• In allergic reactions, basophils release histamine during allergic reactions.
White Blood Count Reference Ranges
*mm3 = cubic millimeter of blood.
Red blood cells, or erythrocytes, are produced in the bone marrow. Their primary function is to transport oxygen to the body tissues.
• Male = 4.5 to 5.5 mcL*
• Female = 4.0 to 4.9 mcL
• RBC is a reflection of blood’s capacity to carry O2 and nutrients through the body
*mcL = microliters
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
