A nurse is gathering data on a patient who has diarrhea.
Which of the following findings is a sign of hypokalemia?

Choice A rationale:

Tachycardia, or a rapid heart rate, is not typically an adverse effect of oxygen therapy. Oxygen therapy is often used to help people with conditions like COPD, COVID-19, emphysema, and sleep apnea get enough oxygen to function and stay well. While tachycardia can be a symptom of these conditions, it is not directly caused by the oxygen therapy itself.

Choice B rationale:

Cracks in the oral mucous membranes can indeed be an adverse effect of oxygen therapy. Oxygen therapy involves the delivery of highly concentrated oxygen, which can cause irritation and dryness in the airways, including the oral mucous membranes. This can lead to cracks and discomfort in the mouth. Therefore, it’s important for healthcare providers to monitor patients receiving oxygen therapy for signs of this adverse effect.

Excessive pulmonary secretions are not typically a direct adverse effect of oxygen therapy. While conditions that often require oxygen therapy, such as pneumonia and COPD, can lead to increased pulmonary secretions, these are symptoms of the underlying disease rather than the oxygen therapy itself.

Choice D rationale:

Poor skin turgor is not typically an adverse effect of oxygen therapy. Skin turgor refers to the elasticity of the skin, and poor skin turgor is often a sign of dehydration. While oxygen therapy can cause dryness of the mucous membranes, it does not typically affect the hydration status of the skin.

Choice A rationale:

Crackles are a common symptom of pleural effusion. They are abnormal lung sounds that are heard when a patient with pleural effusion breathes in. The sound is caused by the opening of small airways and alveoli collapsed by fluid, exudate, or lack of aeration during expiration.

Choice B rationale:

Crepitus is not typically associated with pleural effusion. Crepitus is a crackling or grating sound or feeling produced by air in subcutaneous tissue or by the rubbing together of fragments of broken bone. In the context of respiratory health, crepitus might be felt if there is subcutaneous emphysema, where air gets into tissues under the skin covering the chest wall or neck.

Choice C rationale:

Substernal retractions are not a typical symptom of pleural effusion. Retractions are a sign of respiratory distress, but they are more commonly associated with conditions that cause upper airway obstruction or severe lung disease, such as asthma or pneumonia. Choice D rationale:

Dullness upon percussion is a classic sign of pleural effusion. When there is fluid in the pleural space, it prevents the normal resonant sound produced by the air-filled lungs from being heard. Instead, a dull sound is heard when the chest is percussed.