Abstracts

Rationale: The ketogenic diet (KD) is a medical nutrition treatment for intractable epilepsy. The KD stimulates ketosis by supplying fat (70-90% of total calories) as the major source of calories. Patients typically require urine ketone levels in the range of 4-16 mmol/L to improve seizure control. During periods of fasting of more than 12 hours, ketone levels increase and blood glucose (BG) levels decrease. These disruptions may result in seizures. Providing continuous intravenous (IV) dextrose is not recommended for patients on the KD as it may eliminate ketosis and induce seizures. Lipid intake in parenteral nutrition is restricted to less than 3-4 g/kg body weight (BW) per day (0.13-0.17 g/kg BW/hour) to prevent "fat overload syndrome". Typical parenteral nutrition may deliver a lower fat intake than required for children treated with a KD and also result in lower ketone levels and seizures. Due to these limitations, children treated with a KD may discontinue the diet prior to procedures requiring fasting, such as surgery. We employed a small continuous IV 5% dextrose solution to maintain ketosis and normal BG levels during fasting. Methods: Eight children, aged 3-16 years (mean±SD=8.4±2.3) underwent a surgery or procedure that required 19-36 hours of fasting from March 2009 to May 2012. Body weights were 12.5-28.3 Kg (mean±SD=20.0±2.8). Children received continuous IV 5% dextrose with normal saline during the fasting period. Intravenous solution was calculated as follows: D5W/hour rate= (daily carbohydrate (CHO) allowance x 100)/5 ÷ 24 hours Daily CHO allowance = (daily fluid intake/2) x 0.025 and is the intake needed to maintain safe BG and urine ketones to prevent excessive seizures. For BW (1-10 Kg): Daily CHO allowance= (50 x kg BW) x 0.025 For BW (11-20 Kg): Daily CHO allowance= ({1000+50x(Kg BW-10)}/2) x 0.025 For BW >20 Kg: Daily CHO allowance= ({1500+20x(Kg BW-20)}/2) x 0.025 In two cases, the children's pre-procedure fluid intake was below the recommended daily intake. As such, the pre-procedure daily intake was used to calculate the IV fluid requirements. Paired t-test was performed to compare urine ketone levels prior to and during fasting. BG levels were recorded. Seizure frequency was monitored. Results: D5W rates ranged from 8-20 ml/hr (mean±SD=15.9±3.1). Urine ketone levels were 6-16 mmol/L (mean±SD=12.6±2.9) prior to fasting. Urine ketone levels were 6-16 mmol/L (mean±SD=12.9±2.7) during fasting. There were no significant differences (p=0.589) in ketone levels prior to and during fasting. All BG measurements during fasting were >3.5 mmol/L, within the normal range. No children had an increase in seizure frequency or intensity. Conclusions: Careful calculation of IV fluids allows for stable BG and ketone levels during prolonged fasting in children treated with KD. No children in this cohort experienced a change in seizure frequency or intensity during prolonged fasting, using this method. Discontinuation of the KD is not necessary for children undergoing surgery.