What are the NPO (nothing by mouth) and medication management guidelines for patients undergoing cardiac catheterization?

From the Guidelines

Patients undergoing cardiac catheterization should typically remain NPO for 6-8 hours before the procedure, though clear liquids may be permitted up to 2 hours prior in some cases. The management of medications before cardiac catheterization is crucial to balance the risks of procedural bleeding against maintaining cardiovascular stability and preventing thrombotic events 1. Most morning medications should be taken with a small sip of water, particularly antihypertensives, anti-anginals, and anti-arrhythmics to maintain cardiovascular stability. However, insulin doses are usually reduced to prevent hypoglycemia during fasting, and oral hypoglycemics like metformin should be held 24-48 hours before and after the procedure due to the risk of contrast-induced nephropathy and lactic acidosis.

The guidelines for medication management before cardiac catheterization include:

• Continuing aspirin therapy, as it is recommended that patients already on daily aspirin therapy should take 81 mg to 325 mg before PCI 1
• Holding P2Y12 inhibitors like clopidogrel for 5-7 days before elective procedures to reduce bleeding risk, though this depends on the patient's coronary stent status and thrombotic risk
• Stopping warfarin 3-5 days before the procedure with INR confirmation below 1.8, while direct oral anticoagulants (DOACs) like apixaban and rivaroxaban should be held for 24-48 hours depending on renal function
• Estimating the glomerular filtration rate and adjusting the dosage of renally cleared medications, as recommended in patients undergoing PCI 1

It is also important to note that patients with prior evidence of an anaphylactoid reaction to contrast media should receive appropriate prophylaxis before repeat contrast administration 1. Additionally, the volume of contrast media should be minimized in patients with chronic kidney disease (CKD) to reduce the risk of contrast-induced acute kidney injury (AKI) 1.

Overall, the management of NPO and medications before cardiac catheterization requires careful consideration of individual patient factors and the urgency of the procedure to minimize risks and ensure the best possible outcomes.

From the Research

NPO Guidelines for Cardiac Catheterization

• The traditional practice of ordering patients to take nothing by mouth after midnight before their procedure has been questioned by recent studies, with no evidence to support this practice 2.
• A randomized controlled trial found that allowing patients to eat a heart-healthy diet until the scheduled procedure resulted in significantly more satisfaction with the preprocedural diet, less thirst and hunger, and no increased risk of complications 2.
• Another study found that most patients were fasted for significantly longer than recommended, and pre-hydration was underutilized in patients at high risk of contrast-induced nephropathy, with no episodes of aspiration reported 3.

Medication Management Guidelines

• The management of dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is crucial for patients undergoing cardiac catheterization, with premature cessation of these medications associated with acute stent thrombosis, myocardial infarction, and death 4.
• A narrative review suggests that most noncardiac surgeries or procedures can be performed safely while patients are taking clopidogrel, with recommendations for the management of perioperative DAPT 4.
• A multicentre randomized trial found that no fasting was non-inferior and superior to fasting for the primary composite outcome of aspiration pneumonia, hypotension, hyperglycaemia, and hypoglycaemia, with improved patient satisfaction scores in the no-fasting arm 5.

Key Findings

• The results of these studies suggest that the traditional NPO guidelines for cardiac catheterization may not be necessary, and that allowing patients to eat a heart-healthy diet until the scheduled procedure may improve patient satisfaction and outcomes 2, 5.
• The management of DAPT is crucial for patients undergoing cardiac catheterization, and premature cessation of these medications should be avoided 4.
• Further studies are needed to evaluate the need for fasting prior to non-emergency cardiac catheterization and to establish evidence-based guidelines for medication management 3, 5.