A nurse is caring for a client with chronic obstructive pulmonary disease (COPD). Which intervention is most appropriate to promote oxygenation in this client?

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.

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.