Blog: Are your preoperative patients HANGRY? Debunk the practice of “nil per os” (NPO) after midnight to improve the patient experience

New evidence prompts new carbo-loading ERAS protocols.
By Jonathan Markley, DO, NAPA Director of Regional Anesthesia,
St. Joseph’s University Medical Center; Chairman of Anesthesia, East Orange General Hospital

Every anesthesia clinician has encountered patients who become both hungry and angry while waiting for their procedures. And because we’re human, too, we know what they’re feeling—hungry plus angry equals HANGRY, also known as cranky and irritable. Why are they like this? Because we told them to fast for too many hours before surgery!

Hunger and thirst cause anxiety and have a negative impact on an individual’s emotional state. Prolonged fasting can also produce harmful clinical outcomes, particularly when busy operating rooms delay scheduled operations. A 12-hour fast leads to depletion of glycogen storage, skeletal muscle loss, dehydration, increased insulin resistance, postoperative ileus and even longer length of stays.

Modern preoperative fasting practices date to observations published by Dr. Curtis Mendelson in 1946. He reported that surgical patients who ingested food shortly before their procedure were more likely to aspirate their stomach contents with severe consequences. Although some doctors intuitively believe that preoperative fasting after midnight reduces the risk of pulmonary aspiration by ensuring an empty stomach, this patient guidance of prolonged fasting is not based on any meaningful evidence. Studies now show that fasting after midnight does not result in lower amounts of gastric content or increased gastric PH than following the recommended American Society of Anesthesiologists (ASA) practice guideline.

In 2017, the American Society of Anesthesiologists released updated practice guidelines that maintained its recommendations for six- to eight-hour fasting prior to surgery for low-risk patients, and encouraged clear liquids up to two hours before surgery. Even better than clear liquids, numerous studies published since 1998 have demonstrated positive outcomes associated with preoperative carbohydrate loading. In study after study, research results showed that patients who drink a carbohydrate-rich drink at least two hours before surgery experience less preoperative discomfort due to hunger, thirst, malaise and anxiety (thereby improving the patient experience). In fact, gastric emptying is complete within 90 minutes after healthy patients drink 50 grams of oral carbohydrate. Carbo-loading places the human body in a metabolically fed state, reducing insulin resistance, and preserving whole-body protein and skeletal muscle mass. Significantly, particularly in the era of healthcare reform, oral carbo-loading has also been shown to reduce hospital stays after elective surgery by 20 percent.

Instructions for Carbohydrate-Loading

Based on this evidence, new Enhanced Recovery After Surgery (ERAS) protocols now advise appropriate presurgical patients to drink 100 grams of a high-carbohydrate drink (such as 24 to 32 ounces of Gatorade® or apple or grape juice) on the night before surgery, followed by 50 grams (12 to 16 ounces) of Gatorade or apple or grape juice more than two hours before they arrive for surgery. As an alternative to juice, a variety of commercial products now available can be given to patients in the office or at their preadmission testing visit. These products typically range from $1.50 to $3 for a 10-ounce bottle; patients would require three bottles to effectively carbo-load.

Commercial products developed specifically for preoperative carbo-loading—such as Ensure® Pre-Surgery and Clearfast® Preoperative Beverage—are generally not available in retail pharmacies, but do offer these advantages:

• Provide carbo-loading benefits in a smaller amount of volume, which may improve patient safety
• Contain maltodextrin (a polysaccharide) and fructose vs. just fructose found in juices
• Contain antioxidants zinc and selenium for added immunonutrition
• Offer a uniform product with clear instructions on the bottle.

It is important to note that while the ASA recommends intake of clear liquids, including these carbo-loading products, until two hours before surgery for healthy patients. These guidelines do not necessarily apply to those with comorbid disease due to a variety of unknowns. For example, while gastric emptying of solids is thought to be delayed in patients with diabetic gastroparesis, it is unclear whether this extends to liquids. Similarly, although data suggests that gastric emptying is not influenced by body habitus or uncomplicated Type II diabetes mellitus (DM), until further research is conducted, it is reasonable to consider omitting carbo-loading in patients with the stigmata of chronic DM. That is also true for certain obese patients and patients with symptoms of gastroesophageal reflux disease (GERD).

We can safely produce superior preop experiences and postop clinical outcomes for low-risk patients by replacing the outdated practice of “nil per os” (NPO) after-midnight ritual with oral carbohydrate drinks taken at least two hours before surgery. And while this is good news for patients, an added benefit for providers is that patients who experience less anxiety, fewer ileus symptoms, reduced nitrogen loss, euvolemia and diminished postoperative nausea and vomiting (PONV) report higher satisfaction in survey scores that can boost profitability for anesthesia clinicians and facilities, alike.

…preoperative oral carbo-loading has been shown to reduce hospital stays after elective surgery by 20%. Share on X