You are instructed to administer 40 mg of methadone (Dolophine) subcutaneously for opioid detoxification. Given that you have a concentration of 30 mg/mL on hand, how much should you draw into the syringe?

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:
While PICCs are typically intended for shorter-term use (up to 12 weeks), the fact that a PICC has been in place for 4 weeks is not, in itself, an immediate cause for concern. Regular assessment of the catheter and site is crucial, but the duration of placement alone does not warrant immediate attention.
Choice B rationale:
While it's generally recommended to change PICC dressings every 7 days, a dressing that is 3 days old is not an immediate emergency. The nurse should prioritize changing the dressing as soon as possible, but it does not require the same level of urgency as other potential complications.
Choice C rationale:
A missing securement device is a concern because it can increase the risk of catheter dislodgement or migration. However, it does not necessarily indicate an immediate threat to the patient's well-being. The nurse should promptly address the missing securement device, but it would not be the most pressing issue compared to swelling in the extremity.
Choice D rationale:
Swelling in the upper extremity where the PICC is located is a significant finding that demands immediate attention. It can be a sign of several serious complications, including:
Thrombosis: A blood clot within the vein, which can obstruct blood flow and lead to pain, swelling, and potentially more severe consequences like deep vein thrombosis (DVT) or pulmonary embolism (PE).
Infection: Inflammation and infection at the insertion site or within the bloodstream, which can cause swelling, redness, warmth, and pain. If left untreated, infection can progress to sepsis, a life-threatening condition.
Phlebitis: Inflammation of the vein, which can cause pain, redness, and swelling along the vein.
Infiltration: Leakage of fluids or medications into the surrounding tissue, leading to swelling and discomfort.
Prompt action is crucial in these cases to prevent further complications and ensure patient safety. The nurse should immediately notify the appropriate healthcare provider, initiate necessary interventions, and closely monitor the patient's condition.