Choice A rationale:
Skin and mucous membranes are the most effective and crucial barriers to infection. They provide a continuous physical barrier that prevents pathogens from entering the body. Here's a detailed explanation of their protective mechanisms:
1. Physical Barrier:
Skin: The outermost layer of skin, the epidermis, is composed of tightly packed cells that are difficult for pathogens to penetrate. It's also covered in a layer of sebum, an oily substance that helps to repel water and microorganisms.
Mucous membranes: These moist linings cover the openings of the body, such as the nose, mouth, eyes, and digestive, respiratory, and urogenital tracts. They produce mucus, a sticky substance that traps pathogens and prevents them from entering the body. Mucus also contains enzymes and antibodies that can kill certain pathogens.
2. Chemical Barrier:
Skin and mucous membranes secrete a variety of substances that have antimicrobial properties. These include: Sebum: Contains fatty acids that can kill bacteria and fungi.
Sweat: Contains salt and lysozyme, an enzyme that can break down bacterial cell walls. Saliva: Contains enzymes that can break down food and kill bacteria.
Gastric acid: The highly acidic environment of the stomach kills most pathogens that are ingested.
3. Immune Barrier:
Skin and mucous membranes are home to a diverse community of microbes, known as the microbiome. These microbes play an important role in protecting against infection by competing with pathogens for resources and space.
Mucous membranes contain specialized immune cells, such as M cells and dendritic cells, that can recognize pathogens and initiate an immune response.
In contrast, the other choices are less effective barriers to infection:
Choice B: Gastrointestinal secretions, such as gastric acid, do play a role in preventing infection, but they are not as effective as skin and mucous membranes. Pathogens can still enter the body through the digestive tract, even in the presence of gastric acid.
Choice C: Colonization by host bacteria can actually help to protect against infection by competing with pathogens. However, it is not a primary barrier to infection.
Choice D: Inflammatory processes are a response to infection, not a barrier to it. They occur after pathogens have already entered the body.

Choice A rationale:
It is incorrect to state that the client will not be able to bathe with a central vascular access device.
While certain precautions are necessary to keep the device dry and clean during bathing, bathing is still possible and important for maintaining hygiene.
The nurse should provide specific instructions on how to protect the device during bathing, such as using a waterproof cover or avoiding direct water contact.
Choice B rationale:
It is inaccurate to claim that there is no risk of infection associated with a central vascular access device, even when sterile technique is used during insertion.
Infection is a serious potential complication, and it's crucial to emphasize ongoing infection prevention measures to the client.
The nurse should educate the client about signs and symptoms of infection to watch for and the importance of prompt reporting to healthcare providers.
Choice C rationale:
It is not always necessary to wear a sling on the arm with the central vascular access device.
The need for a sling may depend on the type of device, the client's condition, and the healthcare provider's recommendations.
If a sling is indicated, the nurse should provide instructions on proper use and care to maintain comfort and prevent complications.
Choice D rationale:
This is the correct statement to include in the client's teaching.
Thorough cleaning of the connections prior to accessing the device is essential for preventing infection.
The client should be empowered to advocate for themselves and ensure that all providers follow proper infection control procedures.