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Intraoperative glucose administration influences respiratory quotient during paediatric anaesthesia
K Sandström1, L E Larsson, K Nilsson
1Department of Paediatric Anaesthesia and Intensive Care, Sahlgrenska University Hospital, Gothenburg, Sweden.
Insights
Intraoperative glucose infusion significantly increases the respiratory quotient (RQ) in pediatric patients, indicating a higher glucose oxidation rate. This suggests a shift in metabolic preference during anesthesia and surgery when glucose is administered.
Area of Science:
- Pediatric Anesthesia
- Metabolic Studies
- Indirect Calorimetry
Background:
- Carbohydrate and fat oxidation yield respiratory quotients (RQ) of 1.0 and 0.7, respectively.
- Blood glucose levels often increase during pediatric anesthesia and surgery, even without exogenous glucose.
- Understanding metabolic substrate utilization is crucial in pediatric surgical patients.
Purpose of the Study:
- To investigate whether intraoperative glucose infusion alters the respiratory quotient (RQ).
- To determine if glucose administration indicates a different metabolic preference compared to glucose-free fluid regimens.
- To assess the impact of intraoperative glucose on substrate utilization during pediatric anesthesia.
Main Methods:
- Eighteen pediatric patients (0.5-24 months) underwent anesthesia with controlled ventilation and standard anesthetic agents.
- Indirect calorimetry measured oxygen consumption and carbon dioxide production.
- Patients received either Ringer acetate alone or with a 10% glucose infusion (3 ml.kg-1.h-1), with blood samples analyzed for metabolic markers.
Main Results:
- The group receiving glucose had a significantly higher RQ (0.92 +/- 0.08) compared to the glucose-free group (0.81 +/- 0.06).
- Higher intraoperative blood glucose concentrations were observed in the glucose-infused group.
- Energy expenditure showed no significant difference between groups, though oxygen consumption trended higher without glucose.
Conclusions:
- Intraoperative glucose infusion promotes a higher rate of glucose oxidation in pediatric surgical patients.
- The findings suggest a shift towards carbohydrate metabolism when glucose is administered during anesthesia.
- RQ serves as a valuable indicator of substrate utilization in pediatric anesthesia.
Background:
Oxidation of carbohydrates and fat yields respiratory quotients (RQ) of 1.0 and 0.7 respectively. Maintained or increased blood glucose concentrations are usually seen during paediatric anaesthesia and surgery even without glucose administration. The aim of the present study was to evaluate whether an intraoperative glucose infusion influences the RQ as an indication of a different metabolic preference in comparison to a glucose-free fluid regime.
Methods:
Eighteen children between 0.5 and 24 months of age were studied during anaesthesia with controlled ventilation, oxygen in air, isoflurane, thiopentone, atracurium and fentanyl. Oxygen consumption and carbon dioxide production were measured using indirect calorimetry All children received Ringer acetate as needed; in addition, nine children were given glucose 10%, 3 ml.kg-1.h-1, corresponding to 300 mg.kg-1.h-1. Blood samples for analyses of glucose, lactate, free fatty acids and ketones were taken before and during surgery.
Results:
RQ was significantly higher in the children given glucose 0.92 +/- 0.08, compared to 0.81 +/- 0.06 in the children without glucose (P < 0.01). Oxygen consumption tended to be higher, although not significantly so, in patients without glucose infusion. Energy expenditure was 1.70 +/- 0.29 kcal.kg-1.h-1, without significant group differences. Higher blood glucose concentrations during surgery were found in the children given glucose.
Conclusions:
Our results indicate a higher glucose oxidation rate in patients given glucose during surgery.