Children routinely face prolonged periods without eating or drinking before surgery, often extending hours beyond recommended guidelines, a new study has found.
More than three-fourths of children who had surgery went more than 12 hours without solids before their operations, researchers at Boston Children’s Hospital reported. The study, which examined the records of more than 22,806 children who underwent elective surgery at the hospital between November 2012 and May 2014, found that 10% had gone more than 18 hours without eating.
The results, presented at Clinical Nutrition Week 2015, showed that 36% of children who had surgery at the hospital during the study period went more than six hours without liquids (abstract 2079392). The American Society of Anesthesiologists (ASA) recommends that patients stop drinking liquids two hours and stop eating six hours before an operation. “Despite these reports, many children undergo prolonged preoperative fasting, far exceeding the current ASA recommendations,” the study found.
The time of day that surgery was performed, and to a lesser extent the age of the child, affected the length of preoperative fasting, the researchers noted.
Even though there has been increasing research highlighting the potential health benefits for children of shorter preoperative fasting periods, the study found that the recommendations have yet to be put into clinical practice.
The study was led by J. William Sparks, MD, associate clinical director of operating rooms at Boston Children’s Hospital, in Waltham, Mass., and a member of the Department of Anesthesiology, Perioperative and Pain Medicine. His co-investigators were Nilesh M. Mehta, MD, Departments of Anesthesiology and Critical Care Medicine; Daniela Anderson, MD, the Center for Nutrition; and Craig D. Smallwood, a respiratory therapist.
The children had a median age of nearly 9 years; 57% were boys. Binary logistic regression was used to isolate the factors determining prolonged preoperative fasting times. Reviewing the hospital’s electronic health records, the team collected data on several variables: gender, fasting duration for liquids and solids, the surgical service performing the operation, the time of the surgery and hospital length of stay.
The median duration of preoperative fasting was four hours for liquids and 14 hours for solids (Table). In addition to the 76% of children who went 12 hours or more without eating, another 20% went eight to 12 hours without solids. The deviation from the ASA guidelines on preoperative fasting was the most extreme for solids.
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Preoperative fasting duration was lower for liquids. Still, a full 20% of children had nothing to drink for more than 12 hours before their surgeries, and another 16% went without clear liquids for six to 12 hours.
Why Prolong Fasting?
After analysis of several potential factors behind the prolonged preoperative fasting times, the strongest correlation was found with the time of surgery. Fasting duration increased steadily throughout the day, practically doubling from around 10 hours at 8 a.m., to 20 hours or more by late afternoon, the study found.
Preoperative fasting also increased steadily, although less dramatically, with advancing age of the child.
Infants less than 1 year old went, on average, without liquids for 3.6 hours and without solids for 9.6 hours. Those figures rose to 4.4 hours for liquids and 13.6 hours for solids among children aged 1 to 5 years. Whereas preoperative fasting times for liquids generally stayed the same among older children, fasting time for solids rose to 14.8 hours among patients aged 5 to 12 years, leveling off to 14.5 hours among children aged 12 years and older.
Preoperative fasting duration also varied slightly depending on the surgical service performing the operation, with patients undergoing oral, orthopedic or genitourinary surgery more likely to go longer without drinking or eating, albeit mostly for less than an hour.
The phenomenon of prolonged preoperative fasting occurs even as research in the medical and scientific community increasingly highlights the benefits of shorter periods of abstention from food and drink before surgery, the study noted.
Recent studies have shown an increase in feelings of general malaise, anxiety, weakness, hunger and thirst among patients who have undergone prolonged fasting before surgery.
During fasting, metabolic changes occur as well, including “reduced hepatic glycogen stores, increased gluconeogenesis and increased insulin resistance,” Dr. Sparks said.
By contrast, reduced fasting has been shown to improve patient comfort, with no change or reduction in gastric volume or pH, while also reducing insulin resistance, reducing hyperglycemia/stress response and increasing protein metabolism.
Several factors may be driving the phenomenon, Dr. Sparks said. Parental or patient anxiety over the potential for aspiration during surgery is certainly one reason, he pointed out. But there is also a need to look at whether parents are getting the right information when it comes to the number of hours their children need to go without eating or drinking before surgery, Dr. Sparks said.
To that end, Boston Children’s Hospital has created a pamphlet on preoperative fasting that is given to parents at its Boston campus, he said. At its satellite campus in suburban Boston, the hospital’s nurses are making phone calls to parents to ascertain that they understand the correct fasting times, Dr. Sparks said.
The Boston Children’s Hospital researchers will review patient records after six months to see if there has been a reduction in duration of preoperative fasting, he noted.
The study is also expected to open the way to further research. Dr. Sparks said the next step will be to examine the metabolic effects of prolonged fasting before surgery in children and whether there is an effect on patient outcomes.
“Obviously, the big picture is whether a prolonged fast affects patient outcomes,” he said.
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