Pursed-lip breathing is a technique that helps to slow down the breathing rate, reduce air trapping, and improve gas exchange in clients with COPD. It also helps to relieve dyspnea and anxiety.

Incorrect options:

B) Administer oxygen via nasal cannula at 6 L/min. - This is an incorrect intervention, as clients with COPD are at risk of developing oxygen-induced hypercapnia, a condition where high levels of oxygen reduce the drive to breathe and cause carbon dioxide retention. Oxygen therapy should be administered cautiously and titrated to maintain a target oxygen saturation of 88-92% in clients with COPD.

C) Position the client in a supine position with the head elevated. - This is an incorrect intervention, as a supine position can increase the pressure on the diaphragm and impair lung expansion, worsening dyspnea and hypoxemia in clients with COPD. A semi-Fowler's or high-Fowler's position is preferred, as it allows for maximal lung expansion and reduces the work of breathing.

D) Instruct the client to cough forcefully every hour. - This is an incorrect intervention, as forceful coughing can increase airway resistance, cause bronchospasm, and increase dyspnea in clients with COPD. A more effective coughing technique is to use huff coughing, which involves exhaling forcefully through an open mouth while making a "huff" sound.

Lactic acidosis is a rare but potentially fatal complication of metformin therapy, especially in clients with renal impairment, liver disease, heart failure, or alcohol abuse. It occurs when metformin accumulates in the body and causes an increase in lactate production and a decrease in lactate clearance, leading to metabolic acidosis. Symptoms of lactic acidosis include nausea, vomiting, abdominal pain, hyperventilation, muscle weakness, and confusion.

Incorrect options:

A) Hypoglycemia - This is an incorrect option, as metformin does not cause hypoglycemia by itself. However, hypoglycemia may occur if metformin is combined with other antidiabetic agents that lower blood glucose levels, such as sulfonylureas or insulin.

C) Pancreatitis - This is an incorrect option, as metformin does not cause pancreatitis. However, pancreatitis may occur as a complication of diabetes mellitus or as an adverse effect of other antidiabetic agents, such as glucagon-like peptide-1 (GLP-1) agonists or dipeptidyl peptidase-4 (DPP-4) inhibitors.

D) Hepatotoxicity - This is an incorrect option, as metformin does not cause hepatotoxicity. However, hepatotoxicity may occur as a complication of diabetes mellitus or as an adverse effect of other antidiabetic agents, such as thiazolidinediones or alpha-glucosidase inhibitors.

Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is commonly used to treat pain and inflammation in clients with RA. However, NSAIDs can also inhibit platelet aggregation and prolong bleeding time, increasing the risk of hemorrhage during and after surgery. Therefore, ibuprofen should be discontinued at least 7 days before the surgery.

Incorrect options:

A) Prednisone - This is an incorrect option, as prednisone is a corticosteroid that is used to suppress inflammation and immune responses in clients with RA. Prednisone does not affect bleeding time or platelet function. However, prednisone can increase the risk of infection and delay wound healing, so it should be tapered gradually before the surgery to avoid adrenal insufficiency and withdrawal symptoms.

B) Methotrexate - This is an incorrect option, as methotrexate is a disease-modifying antirheumatic drug (DMARD) that is used to slow down the progression of joint damage and reduce inflammation in clients with RA. Methotrexate does not affect bleeding time or platelet function. However, methotrexate can increase the risk of infection and bone marrow suppression, so it should be discontinued at least 2 weeks before the surgery.

D) Hydroxychloroquine - This is an incorrect option, as hydroxychloroquine is an antimalarial drug that is used to treat mild to moderate RA. Hydroxychloroquine does not affect bleeding time or platelet function. However, hydroxychloroquine can cause ocular toxicity, so it should be monitored regularly by an ophthalmologist.

Disequilibrium syndrome is a neurological complication of hemodialysis that occurs when the rate of solute removal from the blood exceeds the rate of solute removal from the brain, creating an osmotic gradient that causes fluid to shift into the brain cells, resulting in cerebral edema. Symptoms of disequilibrium syndrome include headache, nausea, vomiting, restlessness, confusion, and seizures. It usually occurs during or shortly after the first few dialysis sessions or when there is a large decrease in blood urea nitrogen (BUN) levels.

Incorrect options:

A) Hyperkalemia - This is an incorrect option, as hyperkalemia is a common complication of CKD that occurs when the kidneys are unable to excrete excess potassium. Hemodialysis helps to lower potassium levels by removing it from the blood. However, hyperkalemia may occur between dialysis sessions if the client consumes foods high in potassium or takes medications that increase potassium levels, such as angiotensin-converting enzyme (ACE) inhibitors or potassium-sparing diuretics.

B) Hypertension - This is an incorrect option, as hypertension is a common complication of CKD that occurs when the kidneys are unable to regulate fluid and sodium balance. Hemodialysis helps to lower blood pressure by removing excess fluid and sodium from the blood. However, hypertension may occur between dialysis sessions if the client consumes foods high in sodium or fluid or takes medications that increase blood pressure, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids.

C) Hypocalcemia - This is an incorrect option, as hypocalcemia is a common complication of CKD that occurs when the kidneys are unable to activate vitamin D and promote calcium absorption from the gut. Hemodialysis helps to correct hypocalcemia by adding calcium to the dialysate solution. However, hypocalcemia may occur between dialysis sessions if the client consumes foods low in calcium or takes medications that lower calcium levels, such as phosphate binders or bisphosphonates.