A nurse is providing care for four patients. Which patient should the nurse evaluate first for cognitive impairment?

Choice A rationale:
Metabolic alkalosis is a condition characterized by an increase in the pH of the blood due to an excess of bicarbonate (HCO3-) in the body. It is not typically caused by severe diarrhea. In fact, diarrhea can often lead to a loss of bicarbonate, which can contribute to metabolic acidosis.
Causes of metabolic alkalosis include: excessive vomiting, use of diuretics, and excessive intake of alkali such as antacids. Clinical manifestations of metabolic alkalosis include: muscle twitching, paresthesias, seizures, confusion, and lethargy.
Choice B rationale:
Respiratory alkalosis is a condition characterized by a decrease in the partial pressure of carbon dioxide (PaCO2) in the blood, leading to an increase in blood pH. It is caused by hyperventilation, which removes excess CO2 from the body. Severe diarrhea does not typically cause hyperventilation.
Causes of respiratory alkalosis include: anxiety, hyperventilation syndrome, high altitude sickness, and pulmonary embolism. Clinical manifestations of respiratory alkalosis include: lightheadedness, dizziness, paresthesias, palpitations, and tetany.
Choice C rationale:
Respiratory acidosis is a condition characterized by an increase in the partial pressure of carbon dioxide (PaCO2) in the blood, leading to a decrease in blood pH. It is caused by hypoventilation, which prevents the body from removing enough CO2. Severe diarrhea does not typically cause hypoventilation.
Causes of respiratory acidosis include: chronic obstructive pulmonary disease (COPD), pneumonia, asthma, and neuromuscular disorders.
Clinical manifestations of respiratory acidosis include: headache, confusion, somnolence, and coma.
Choice D rationale:
Metabolic acidosis is a condition characterized by a decrease in the pH of the blood due to an excess of acid in the body or a loss of bicarbonate. Severe diarrhea can lead to metabolic acidosis through several mechanisms:
Loss of bicarbonate in the stool: Diarrhea often contains a significant amount of bicarbonate, which can be lost from the body in large amounts during severe diarrheal episodes. This loss of bicarbonate can lead to a decrease in the blood's pH, resulting in metabolic acidosis.
Dehydration: Severe diarrhea can also lead to dehydration, which can concentrate acids in the blood and contribute to metabolic acidosis.
Lactic acidosis: In some cases, severe diarrhea can also cause lactic acidosis, a type of metabolic acidosis that occurs when there is a buildup of lactic acid in the body. This can happen due to impaired circulation or tissue hypoxia, which can occur as a complication of severe diarrhea.

Rationale for Choice A:
While it's important for the primary healthcare provider to be informed about the CD4+ results, it's not the first action the nurse should take. The priority is to implement appropriate infection control measures to protect the patient, other patients, and healthcare staff.
CD4+ cell count is a crucial indicator of the patient's immune status. A count of 180/mm is significantly low, suggesting a weakened immune system and increased vulnerability to infections. However, informing the provider alone doesn't directly address the immediate need for infection control.
Rationale for Choice B:
Airborne Precautions are specifically used for patients with known or suspected airborne infections, such as tuberculosis, measles, or varicella. These precautions involve the use of negative pressure rooms and N95 respirators.
In this case, the patient's TB skin test was negative, indicating no evidence of active tuberculosis infection. Implementing Airborne Precautions unnecessarily could lead to excessive resource utilization and potential stigmatization of the patient.
Rationale for Choice C:
Droplet Precautions are used for patients with infections that can be spread through large respiratory droplets, such as influenza, pertussis, or meningococcal meningitis. These precautions involve the use of masks and eye protection.
While the patient's symptoms of fever, night sweats, and severe cough could be consistent with a droplet-spread infection, there's no definitive evidence to support this at the present time. Initiating Droplet Precautions without a clear indication could also lead to unnecessary resource use and potential anxiety for the patient.
Rationale for Choice D:
Standard Precautions are the foundation of infection control and should be used for all patients, regardless of their known or suspected infection status. These precautions include hand hygiene, use of personal protective equipment (PPE) when indicated, and safe handling of sharps and bodily fluids.

By implementing Standard Precautions, the nurse can effectively minimize the risk of transmission of pathogens, protecting both the patient and other individuals in the healthcare setting. This is the most appropriate first action to ensure a safe and appropriate level of care.