Comparison of Intraoperative Glycemic Levels in Infants with the Use of Ringer Lactate with Supplemental 1% versus 2% Dextrose as Maintenance Fluid.

CONTEXT: There is no consensus regarding the concentration of dextrose supplementation to be used in pediatric patients intraoperatively. AIMS: The primary objective was to assess the effect of using Ringer lactate (RL) with 1% versus 2% dextrose as maintenance fluid in infants on intraoperative blood glucose levels. The secondary objectives included assessment of incidence of hyperglycemia and hypoglycemia in both groups. SETTINGS AND
DESIGN: This was a prospective randomized study conducted in a tertiary care teaching institute. SUBJECTS AND METHODS: Forty infants undergoing cheiloplasty or palatoplasty were included. All patients fasted 6 h for solids and formula feeds, 4 h for breast milk, and 2 h for clear fluids and received general anesthesia as per standardized protocol. Patients belonging to Group 1 received RL with 1% dextrose supplementation, whereas Group 2 received RL with 2% dextrose added to it as an intraoperative maintenance fluid. Random blood sugar (RBS) was checked preoperatively and then at 60 min and 120 min after induction. Hypoglycemia was defined as RBS <70 mg/dL and hyperglycemia as RBS >150 mg/dL. STATISTICAL ANALYSIS USED: Independent sample ttest and Pearson's Chisquare test were used for statistical analysis.
RESULTS: Preoperative RBS was comparable in both groups. RBS at 60 and 120 min was significantly higher in Group 2 compared to Group 1. There was no incidence of hypoglycemia in both groups, and the incidence of hyperglycemia was similar in both groups.
CONCLUSION: Use of RL with 2% dextrose as intraoperative maintenance fluid in infants resulted in significant increase in blood sugar levels as compared to addition of 1% dextrose although the incidence of hyperglycemia remained comparable in both groups. Copyright:

INTRODUCTION

For the prevention of intraoperative hypoglycemia, dextrose is very commonly added to perioperative maintenance fluids. However, there is no consensus regarding the concentration of dextrose for supplementation intraoperatively in pediatric patients. Various practices exist across the globe, and many practitioners follow the age-old norm of adding 2% dextrose to maintenance fluid for infants <10 kg body weight and 1% dextrose for older children of <2 years of age. Conflicting practices do exist, and it is even suggested that there is no need for dextrose supplementation intraoperatively as stress response to surgery itself will result in hyperglycemia and further supplementation may actually worsen the hyperglycemic condition. However, the common practice is the addition of 1% dextrose to maintenance fluids to avoid a catabolic response and also as a safe measure to prevent intraoperative hypoglycemia which has serious sequelae, especially in younger children. The requirement of optimal dextrose concentration and the rate of fluid administration vary according to the type of surgery as well. It has been shown that the use of 1%–2.5% dextrose containing isotonic fluids as maintenance fluid in infants undergoing surgery decreases the incidence of hypoglycemia as well as hyperglycemia.[1]

The primary objective of the present study was to assess the effect of using Ringer lactate (RL) with 1% versus 2% dextrose as maintenance fluid in infants undergoing surgery under general anesthesia without supplemental regional anesthesia on intraoperative blood glucose levels. The secondary objectives included assessment of the incidence of hyperglycemia and hypoglycemia and changes in hemodynamics with the use of these two fluid regimens.

SUBJECTS AND METHODS

The present study was a prospective randomized study conducted after obtaining institutional ethical committee clearance and consent from parents of the study participants. Forty infants undergoing cheiloplasty or palatoplasty belonging to the American Society of Anesthesiologists physical status Class 1 were included in the study. Infants of diabetic mothers, those with diabetes, those on intravenous fluids, and those getting glucose supplements orally were excluded from the study.

Following a detailed preanesthetic evaluation, patients were recruited into the study and were kept fasting 6 h for solids and formula feeds, 4 h for breast milk, and 2 h for clear fluids. On the day of surgery, they were randomly allotted to either Group 1 or Group 2 based on computer-generated random sequence of numbers, and concealment of allocation was ensured by using sequentially numbered opaque sealed envelopes. Each group comprised twenty patients. Syrup triclofos 75 mg.kg-1 body weight was given to children aged above 6 months, 2 h prior to the induction. All patients received general anesthesia as per a standardized protocol. Patients belonging to Group 1 received RL with 1% dextrose supplementation, whereas those belonging to Group 2 received RL with 2% dextrose added to it as intraoperative maintenance fluid.

After attaching standard pre-induction monitors such as pulse oximeter, electrocardiograph, and noninvasive blood pressure monitors, all infants were induced with 8% sevoflurane in oxygen using a Jackson–Rees circuit, and a peripheral intravenous line was secured. The first random blood sugar (RBS) reading was taken soon after induction, before initiating intravenous fluid administration. All blood sugar values were checked using a standard glucometer (FreeStyle Optium H System, Copyright© 2015 Abbott Laboratories. Abbott Park, Illinois, USA) with test strips. If the fasting RBS reading was below 70 mg/dL, 25% dextrose at 1 mL.kg-1 was administered intravenously (IV) as a bolus to correct hypoglycemia and those infants were ousted from the study.

All patients were given midazolam 0.05 mg.kg-1 body weight, glycopyrrolate 5 μg.kg-1 body weight, and fentanyl 3 μg.kg-1 body weight IV. An additional bolus of 1 mg.kg-1 of propofol was given followed by suxamethonium 2 mg.kg-1 body weight, and the patients were intubated with appropriate-sized, south pole-facing, uncuffed, preformed endotracheal tubes. Intraoperatively, the patients were ventilated with 50% air, 50% oxygen, and isoflurane 1%–1.5% with gas flow rates of 1 L/min using a closed circuit. After intubation, atracurium 0.5 mg.kg-1 body weight was given IV. Intraoperatively, mechanical ventilation was done at the rate of 20–24 breaths per min with a tidal volume of 8–10 mL.kg-1 body weight to maintain end-tidal carbon dioxide between 30 and 35 mmHg.

Intraoperatively, RBS was checked hourly using capillary blood samples for 2 h. Hypoglycemia[2] was defined as RBS <70 mg/dL and hyperglycemia[3] as RBS >150 mg/dL. At any point during the study, in both the groups, if the RBS reading was <70 mg/dL, 25% dextrose at 1 mL.kg-1 was given as IV bolus to correct hypoglycemia. No intervention was done for RBS values up to 200 mg/dL. If the levels exceeded >200 mg/dL, dextrose-containing solution was changed to plain RL. Intraoperative maintenance fluid was administered according to body weight based on the Holliday and Segar formula.[4] Any losses requiring fluid bolus to be administered were corrected using RL. Blood loss exceeding 10% of the estimated blood volume was replaced with packed red blood cells.

Measurements of heart rate (HR), systolic blood pressure (SBP), and mean arterial pressure were noted at different time intervals starting from pre-induction and then at 15 min intervals for 2 h. At the end of surgery, neuromuscular blockade was reversed with neostigmine and glycopyrrolate, and the patients were extubated on table when awake with return of airway reflexes. The total volume of intravenous fluid used as well as the volume and the number of times 25% dextrose bolus was administered to correct hypoglycemia, if required, were also noted.

Independent sample t-test was used to analyze and compare the baseline blood sugar values and values at 60 min and 120 min between the two groups. Pearson's Chi-square test was used to calculate the incidence of hyper- and hypoglycemia. Statistical analysis was done using IBM SPSS Statistics 20 for Windows 8 (SPSS Inc., Chicago, Illinois, USA).

RESULTS

Forty patients were included in the study [Table 1]. The mean age, weight, and distribution of gender were comparable in both groups [Table 2]. Preoperative RBS was comparable in both groups. RBS measured at 60 and 120 min was significantly higher in Group 2 compared to Group 1 [Figure 1 and Table 3]. There was no incidence of hypoglycemia in both groups throughout the study period, and no patient in either group required administration of 25% dextrose. Volume of RL used and the incidence of hyperglycemia (RBS >150 mg/dL) were similar in Groups 1 and 2 during the study period [20% and 30%, respectively, Table 4]. HR and SBP were comparable in both groups throughout the study period [Table 5].

Table 1

CONSORT flow diagram

Table 2

Comparison of age, weight, and gender

Variables	Mean±SD		P
	Group 1	Group 2
Age in months	10.33±5.59	9.13±4.30	0.190
Weight (kg)	8.57±2.05	9.34±2.43	0.185
Gender, n (%)			0.333
Male	10 (50)	6 (30)
Female	10 (50)	14 (70)

SD=Standard deviation

Figure 1

Changes in random blood sugar

Table 3

Comparison of RBS between the Group R and Group D

Time	Mean±SD		P
	Group 1	Group 2
Induction	95.37±12.57	98.74±21.72	0.347
60 min	122.1±18.9	141.3±34.4	0.010
120 min	143.9±14.9	151.6±17.7	0.021

GRBS=Glucometer random blood sugar, SD=Standard deviation

Table 4

Mean volume of Ringer lactate used and incidence of hyperglycemia

Variables	Mean±SD		P
	Group 1	Group 2
IV fluid volume (mL)	183.58±52.42	191.17±48.66	0.413
RBS values, n (%)
>150 mg/dL	16 (80)	14 (70)	0.716
<150 mg/dL	4 (20)	6 (30)

IV=Intravenously, SD=Standard deviation, RBS=Random blood sugar

Table 5

Comparison of heart rate and mean arterial pressure

Time	Mean±SD		P
	Group 1	Group 2
Comparison of heart rate (per min)
Induction	112.87±13.36	108.33±13.83	0.158
30	127.00±10.51	122.20±12.59	0.125
60	125.20±10.37	120.80±12.58	0.247
90	125.93±10.39	121.23±12.35	0.187
120	126.73±11.33	120.50±12.36	0.232
Comparison of systolic blood
pressure (mm Hg)
Induction	85.4±12.9	87.9±12.0	0.524
30	77.2±14.9	83.1±11.2	0.098
60	85.4±4.7	86.6±5.6	0.486
90	81.5±5.3	84.7±6.4	0.183
120	82.5±6.2	87.3±6.6	0.050

SD=Standard deviation

DISCUSSION

Intraoperative hypoglycemia is a major concern for anesthetists as it may result in seizures and brain damage, which lead to developmental delays, physical and learning disabilities, and its extreme manifestations can even lead to death[56789] if not recognized on time and corrected promptly. The clinical manifestations of hypoglycemia under anesthesia may be blunted or could be easily misinterpreted as response to inadequate depth of general anesthesia. The rationale for the addition of glucose to the intraoperative maintenance fluids of pediatric patients is based on the fact that glucose is required as approximately 20% of the normal caloric needs are provided by it. Therefore, glucose supplementation becomes necessary to prevent starvation ketoacidosis and protein degradation in patients who are kept fasting prior to surgery.[10] This practice, in turn, would limit postoperative energy deficit and hyperglycemia, provide substrate for energy requirements, and thereby avoid perioperative hypoglycemia.[11]

Under general anesthesia, due to stress response of anesthesia and surgery, usually a catecholamine surge happens, which results in a relative insulin resistance and glycogenolysis manifesting as elevated blood sugar levels. Increased levels of cortisol and catecholamines augment glucose production because of increased hepatic glycogenolysis and gluconeogenesis along with reduced peripheral utilization of glucose.[1213]

Dubois et al.[11] found that blood glucose levels had increased postoperatively in patients who received 1% and 2.5% dextrose and also in the group that did not receive dextrose with RL. However, they were of the opinion that a concentration of 1% dextrose was advantageous over higher concentrations as near-normal blood sugar values were seen intraoperatively. They concluded that 1% dextrose in RL resulted in moderate postoperative hyperglycemia but avoided any perioperative hypoglycemic events.

In another study by Barua et al.[14] where plain RL was compared with the addition of 2% dextrose to RL, it was shown that the use of RL with 2% dextrose supplementation intraoperatively resulted in significant hyperglycemia in infants undergoing facial cleft surgeries. Berleur et al.[15] investigated the use of RL solution with low dextrose concentration and had recommended RL with 0.9% or 1% dextrose for intraoperative fluid therapy in pediatric patients, as that concentration was found to reduce the risk of hyponatremia as well as hypoglycemia.

Hyperglycemia in children also has detrimental effects such as intraventricular hemorrhage, osmotic diuresis, impaired immunity, delayed wound healing, renal injury, and neuronal lactic acidosis.[16171819202122] Although in our study it was shown that addition of both 1% and 2% dextrose to RL resulted in intraoperative hyperglycemia, use of RL alone in pediatric patients should be practiced only with regular monitoring of blood sugar levels. In circumstances where regular RBS monitoring is not immediately available, use of RL with 1% dextrose supplementation seems to be a safer practice.

The major drawback of our study was that the blood glucose estimation was done using capillary blood with glucometer with test strips. Use of blood glucose measurements with arterial blood gas analyzers would have yielded more accurate results. As arterial lines are not usually put in facial cleft surgeries and obtaining arterial blood sample intraoperatively was difficult in our patients as the infants were almost fully covered with surgical drapes, we opted for capillary sample for the estimation of blood glucose levels.

CONCLUSION

Use of RL with 2% dextrose as intraoperative maintenance fluid in infants resulted in a significant increase in blood sugar levels as compared to addition of 1% dextrose although the incidence of hyperglycemia remained comparable in both groups during the study period.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.