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BLOOD GLUCOSE CONCENTRATIONS IN CHILDREN UNDERGOING OUTPATIENT DENTAL ANAESTHESIA
Br. J. Anaesth. (1984), 56,1225
BLOOD GLUCOSE CONCENTRATIONS IN CHILDREN UNDERGOING OUTPATIENT DENTAL ANAESTHESIA A. PADFIELD SUMMARY
Hypoglycaemia may be manifested by pallor, sweating, hypothermia, headache, faintness or, more seriously, convulsions and coma leading to permanent brain damage. It is associated also with biochemical abnormalities, the most significant being hyperknlnpmin which, at worst, may cause cardiac arrest. Both hypoglycaemia and hyperkalaemia may aggravate the effects of anoxia and hypercarbia. Diagnosis of hypoglycaemia in children is subject to variation. Different authors have defined it as a blood glucose concentration of 3.33 mmol litre"1 (60 mg dl"1) (Bowie, Mulligan and Schwartz, 1963), 2.78 mmol litre"1 (SOmgdl"1) (Erhlich, 1971) and 2.22 mmol litre"1 (^mgdl" 1 ) (Cornblath and Schwartz, 1966; Habbick, McNeish and Stephenson, 1971). The last value is used in this paper. Previous studies of blood glucose concentrations in children undergoing general anaesthesia for surgery have shown that hypoglycaemia is not uncommon, although this depends on the criteria used for definition. In 1972, Watson found that eight (10%) of his sample of 80 children had blood-glucose concentrations of 40mgdl"1 (2.22 mmol litre"1) or less, and that the recognized adult response of an increase in blood glucose concentration during surgery did not always occur. Five of the eight children were aged 4yr or less. Bevan and Burn (1973) investigated the prevalence of hypoglycaemia and associated metabolic acidosis at induction of anaesthesia in 243 children. Thirty per cent of 142 children who has fasted for at least 8 h had blood glucose concentrations of less than 60mgdl~1 (3.33 mmol litre"1). Thomas (1974) found that 28% of children younger than 4yr, who had fasted, were hypoAdrian Padfield, ALB., F.F.A.R.C.S., D.A., G.A. Department, Charles Clifford Dental Hospital, Sheffield S10 2SZ.
glycaemic (<2.22mmollitre- 1 ), but that all children given milk 4h before surgery had blood glucose concentrations greater than this value. In a study on children awaiting tonsillectomy (Kelnar, 1976), four of 32 were hypogrycaemic (<2.22 mmol litre"1). The children were aged between 3 and 11 yr. Graham (1979) estimated plasma glucose concentrations in 31 children aged less than 5 yr undergoing outpatient general anaesthesia for simple surgical operations and found that no patient had a plasma glucose concentration less than 2.8 mmol litre"1 in spite of at least an 8-h fast. PATIENTS AND METHODS
In this study 56 patients aged between 2 and 16yr (fig. 1) undergoing dental extraction under general
10-
m
l •s 5-
2
4
6 8 10 12 14 16 Age(yr)
FIG. 1. Age distribution of patients. © The Macmillan Prets Ltd 1984
Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
Fifty-six children, aged between 2 and 16yr, undergoing dental extractions under general anaesthesia had their plasma glucose concentrations estimated before surgery. The mean concentration was 3.80 mmol litre"1. The lowest value was 2.2 mmol litre"1 in spite of starvation for 16.5 h. It is possible that outpatienta are less susceptible to hypoglycaemia.
1226
BRITISH JOURNAL OF ANAESTHESIA 15-, E2 Morning patients I—I Afternoon patients
2.5
3.0
3.5 4.0 4.5
5.0
2.0
5.5 1
5.0 2.0 3.0
4.0
5.0 1
Plasma glucose (mmo) litre' ) FIG. 2. Scatter of blood glucose concentrations.
3.0 4.0
Plasma glucose (mmol litre' ) FIG.
3. Comparative blood glucose concentrations in morning and afternoon patients.
6.0-1
x \
5.0 •
o OD O
4.0-
O
o oo
o
V
°
o o
•*
3.0-
2.0 10
12
14
16
18
Time after food (h) FIG. 4. Blood glucose concentrations in relation to time after food, x = Patients received water only; O = exact duration uncertain; O = afternoon theatre list; • = morning theatre list.
20
Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
2.0
1227
OUTPATIENT DENTAL ANAESTHESIA
RESULTS
No child had a plasma glucose concentration of less than 2.22 mmol litre"1, although one who had fasted for 16.5 h had a concentration of this value (fig. 2). No child had clinical evidence of hypoglycaemia. The mean plasma glucose concentration was 3.87 mmol litre"1 for afternoon patients and 3.73 mmol litre"1 for morning patients. There was no statistically significant difference between the two (fig. 3). There was no correlation between the period of fasting and the glucose concentration (fig. 4). DISCUSSION Very few patients younger than 4 yr undergo dental extractions at our hospital and this may explain the findings of this study. Previous reports have emphasized the problem of hypoglycaemia in patients younger than 4 yr. However, Graham's study (1979) of outpatients younger than 5 yr found no evidence of hypoglycaemia, and he suggested that outpatients might represent a special category distinct from the patients studied in previous papers. There is no doubt that children may become hypoglycaemic after fasting (Chaussain, 1973), but the difference between outpatients and inpatients may be the difference between a relatively rapid, exciting or frightening progression from admission to operation and a slower, more structured admission to hospital with preoperative sedation. In the former, other factors which can increase the blood glucose concentration may be at work, factors which may not be pertinent in the inpatient. One possibility is unadmitted food or drink within the prescribed fasting period; another is the stimulation of gluconeogenesis by increases in catecholamine con-
centrations as a result of fear. The former will always be difficult to prove, but the latter offers a further field of investigation. It appears that the young dental outpatient over the age of 4yr is not at risk from hypoglycaemia during general anaesthesia. ACKNOWLEDGEMENTS
I wish to thank Mr J. V. Townend for suggesting this study and Mrs C. King for typing the manuscript. REFERENCES
Bevan, J. C , and Burn, M. C. (1973). Acid-base changes and anaesthesia. The influence of pre-operarive narration and feeding in paediatric surgical patients. Anaesthesia, 28,415. Bowie, M. D., Mulligan, P. B., and Schwartz, R. (1963). Intravenous glucose tolerance in the normal newborn infant: the effects of a double dose of glucose and insulin. Pediatrics, 31, 590. Chaussain, J. L. (1973). Glycemic response to 24 hour fast in normal children and children with ketotic hypoglycemia. / . PWiarr., 82,438. Cornblath, M., and Schwartz, R. (1966). Disordtn of Carbohydrate Metabolism in Infancy, 2nd edn, p. 345. Philadelphia: Saunders. F.hrlich, R. M. (1971). Hypoglycaemia in infancy and childhood. Arch. Dis. Child., 46, 716. Graham, I. F. M. (1979). Preoperative starvation and plasma glucose concentrations in children undergoing outpatient anaesthesia. Br. J. Anaetth., 51,161. Habbick, B. F., McNeish, A. S., and Stephenson, J. P. B. (1971). Diagnosis of ketotic hypoglycaemia of childhood. Arch. Dii. Child., 46,295. Kelnar, C. J. H. (1976). Hypoglycaemia in children undergoing adenotonsillectomy. Br. Med. J., 1,751. Thomas, D. K. M. (1974). Hypoglycaemia in children before operation: its incidence and prevention. Br. J. Anaetth., 46,66. Watson, B. G. (1972). Blood glucose levels in children during surgery. Br. J. Anaesth., 44, 712.
Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
anaesthesia had blood samples taken either before the i.v. induction, or immediately following the inhalation induction of anaesthesia. The samples were placed in fluoride bottles and analysed for plasma glucose concentration by an automated glucose oxidase process according to the Trinder method. No premedication was given and anaesthesia was induced either with methohexitone i.v. or with nitrous oxide and halothane in oxygen. Thirty-four patients were anaesthetized in morning sessions and 22 during afternoon sessions. The period of fasting was 10- 14h for the morning group and 5-20 h for afternoon patients (four of whom had fasted from the previous evening).
BRITISH JOURNAL OF ANAESTHESIA
1228 BLUTGLUCOSEKONZENTRATIONEN BEI KINDERN WAHREND AMBULANTER NARKOSEN ZU ZAHNEXTRAKTIONEN
CONCENTRACIONES DE GLUCOSA EN LA SANGRE EN NINOS SOMETIDOS A ANESTESIA DENTAL EN CONSULTORIO
ZUSAMMENFASSUNG
SU MARIO
Bei 56 Rindera von 2 bis 16 Jahren, die in Vollnarkose einer Zahnextraktion unterzogen wurden, wurde prfioperativ die Planmaglucosekonzentrarion bestimmt. Die mittlere Konzentration lag bei 3,8 mmolliter"1. Der niedrigste Wert betrug 2,2 mmol liter"1 trotz Fasten uber 16,5 Stunden. Mdglicherweise sind ambulante Patienten weniger anffiilig fur Hypoglykamie.
Antes de la ciru jia, se evaluaron las concentracioDcs de glucosa en el plasma de 56 ninos de 2 a 16anos de edad tometidos a extracciones dentales bajo anestesia general. La concentracion media era de 3,80 mmol litro "'. El valor mis bajo era de 2,2 mmol litro"1 a pesar de encontrarse de ayunas durante 16,5 h. Es posible que los pacicntes ambulatorios sean menos susctptiblcs a la hipoglicemia. Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
BLOOD GLUCOSE CONCENTRATIONS IN CHILDREN UNDERGOING OUTPATIENT DENTAL ANAESTHESIA A. PADFIELD SUMMARY
Hypoglycaemia may be manifested by pallor, sweating, hypothermia, headache, faintness or, more seriously, convulsions and coma leading to permanent brain damage. It is associated also with biochemical abnormalities, the most significant being hyperknlnpmin which, at worst, may cause cardiac arrest. Both hypoglycaemia and hyperkalaemia may aggravate the effects of anoxia and hypercarbia. Diagnosis of hypoglycaemia in children is subject to variation. Different authors have defined it as a blood glucose concentration of 3.33 mmol litre"1 (60 mg dl"1) (Bowie, Mulligan and Schwartz, 1963), 2.78 mmol litre"1 (SOmgdl"1) (Erhlich, 1971) and 2.22 mmol litre"1 (^mgdl" 1 ) (Cornblath and Schwartz, 1966; Habbick, McNeish and Stephenson, 1971). The last value is used in this paper. Previous studies of blood glucose concentrations in children undergoing general anaesthesia for surgery have shown that hypoglycaemia is not uncommon, although this depends on the criteria used for definition. In 1972, Watson found that eight (10%) of his sample of 80 children had blood-glucose concentrations of 40mgdl"1 (2.22 mmol litre"1) or less, and that the recognized adult response of an increase in blood glucose concentration during surgery did not always occur. Five of the eight children were aged 4yr or less. Bevan and Burn (1973) investigated the prevalence of hypoglycaemia and associated metabolic acidosis at induction of anaesthesia in 243 children. Thirty per cent of 142 children who has fasted for at least 8 h had blood glucose concentrations of less than 60mgdl~1 (3.33 mmol litre"1). Thomas (1974) found that 28% of children younger than 4yr, who had fasted, were hypoAdrian Padfield, ALB., F.F.A.R.C.S., D.A., G.A. Department, Charles Clifford Dental Hospital, Sheffield S10 2SZ.
glycaemic (<2.22mmollitre- 1 ), but that all children given milk 4h before surgery had blood glucose concentrations greater than this value. In a study on children awaiting tonsillectomy (Kelnar, 1976), four of 32 were hypogrycaemic (<2.22 mmol litre"1). The children were aged between 3 and 11 yr. Graham (1979) estimated plasma glucose concentrations in 31 children aged less than 5 yr undergoing outpatient general anaesthesia for simple surgical operations and found that no patient had a plasma glucose concentration less than 2.8 mmol litre"1 in spite of at least an 8-h fast. PATIENTS AND METHODS
In this study 56 patients aged between 2 and 16yr (fig. 1) undergoing dental extraction under general
10-
m
l •s 5-
2
4
6 8 10 12 14 16 Age(yr)
FIG. 1. Age distribution of patients. © The Macmillan Prets Ltd 1984
Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
Fifty-six children, aged between 2 and 16yr, undergoing dental extractions under general anaesthesia had their plasma glucose concentrations estimated before surgery. The mean concentration was 3.80 mmol litre"1. The lowest value was 2.2 mmol litre"1 in spite of starvation for 16.5 h. It is possible that outpatienta are less susceptible to hypoglycaemia.
1226
BRITISH JOURNAL OF ANAESTHESIA 15-, E2 Morning patients I—I Afternoon patients
2.5
3.0
3.5 4.0 4.5
5.0
2.0
5.5 1
5.0 2.0 3.0
4.0
5.0 1
Plasma glucose (mmo) litre' ) FIG. 2. Scatter of blood glucose concentrations.
3.0 4.0
Plasma glucose (mmol litre' ) FIG.
3. Comparative blood glucose concentrations in morning and afternoon patients.
6.0-1
x \
5.0 •
o OD O
4.0-
O
o oo
o
V
°
o o
•*
3.0-
2.0 10
12
14
16
18
Time after food (h) FIG. 4. Blood glucose concentrations in relation to time after food, x = Patients received water only; O = exact duration uncertain; O = afternoon theatre list; • = morning theatre list.
20
Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
2.0
1227
OUTPATIENT DENTAL ANAESTHESIA
RESULTS
No child had a plasma glucose concentration of less than 2.22 mmol litre"1, although one who had fasted for 16.5 h had a concentration of this value (fig. 2). No child had clinical evidence of hypoglycaemia. The mean plasma glucose concentration was 3.87 mmol litre"1 for afternoon patients and 3.73 mmol litre"1 for morning patients. There was no statistically significant difference between the two (fig. 3). There was no correlation between the period of fasting and the glucose concentration (fig. 4). DISCUSSION Very few patients younger than 4 yr undergo dental extractions at our hospital and this may explain the findings of this study. Previous reports have emphasized the problem of hypoglycaemia in patients younger than 4 yr. However, Graham's study (1979) of outpatients younger than 5 yr found no evidence of hypoglycaemia, and he suggested that outpatients might represent a special category distinct from the patients studied in previous papers. There is no doubt that children may become hypoglycaemic after fasting (Chaussain, 1973), but the difference between outpatients and inpatients may be the difference between a relatively rapid, exciting or frightening progression from admission to operation and a slower, more structured admission to hospital with preoperative sedation. In the former, other factors which can increase the blood glucose concentration may be at work, factors which may not be pertinent in the inpatient. One possibility is unadmitted food or drink within the prescribed fasting period; another is the stimulation of gluconeogenesis by increases in catecholamine con-
centrations as a result of fear. The former will always be difficult to prove, but the latter offers a further field of investigation. It appears that the young dental outpatient over the age of 4yr is not at risk from hypoglycaemia during general anaesthesia. ACKNOWLEDGEMENTS
I wish to thank Mr J. V. Townend for suggesting this study and Mrs C. King for typing the manuscript. REFERENCES
Bevan, J. C , and Burn, M. C. (1973). Acid-base changes and anaesthesia. The influence of pre-operarive narration and feeding in paediatric surgical patients. Anaesthesia, 28,415. Bowie, M. D., Mulligan, P. B., and Schwartz, R. (1963). Intravenous glucose tolerance in the normal newborn infant: the effects of a double dose of glucose and insulin. Pediatrics, 31, 590. Chaussain, J. L. (1973). Glycemic response to 24 hour fast in normal children and children with ketotic hypoglycemia. / . PWiarr., 82,438. Cornblath, M., and Schwartz, R. (1966). Disordtn of Carbohydrate Metabolism in Infancy, 2nd edn, p. 345. Philadelphia: Saunders. F.hrlich, R. M. (1971). Hypoglycaemia in infancy and childhood. Arch. Dis. Child., 46, 716. Graham, I. F. M. (1979). Preoperative starvation and plasma glucose concentrations in children undergoing outpatient anaesthesia. Br. J. Anaetth., 51,161. Habbick, B. F., McNeish, A. S., and Stephenson, J. P. B. (1971). Diagnosis of ketotic hypoglycaemia of childhood. Arch. Dii. Child., 46,295. Kelnar, C. J. H. (1976). Hypoglycaemia in children undergoing adenotonsillectomy. Br. Med. J., 1,751. Thomas, D. K. M. (1974). Hypoglycaemia in children before operation: its incidence and prevention. Br. J. Anaetth., 46,66. Watson, B. G. (1972). Blood glucose levels in children during surgery. Br. J. Anaesth., 44, 712.
Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015
anaesthesia had blood samples taken either before the i.v. induction, or immediately following the inhalation induction of anaesthesia. The samples were placed in fluoride bottles and analysed for plasma glucose concentration by an automated glucose oxidase process according to the Trinder method. No premedication was given and anaesthesia was induced either with methohexitone i.v. or with nitrous oxide and halothane in oxygen. Thirty-four patients were anaesthetized in morning sessions and 22 during afternoon sessions. The period of fasting was 10- 14h for the morning group and 5-20 h for afternoon patients (four of whom had fasted from the previous evening).
BRITISH JOURNAL OF ANAESTHESIA
1228 BLUTGLUCOSEKONZENTRATIONEN BEI KINDERN WAHREND AMBULANTER NARKOSEN ZU ZAHNEXTRAKTIONEN
CONCENTRACIONES DE GLUCOSA EN LA SANGRE EN NINOS SOMETIDOS A ANESTESIA DENTAL EN CONSULTORIO
ZUSAMMENFASSUNG
SU MARIO
Bei 56 Rindera von 2 bis 16 Jahren, die in Vollnarkose einer Zahnextraktion unterzogen wurden, wurde prfioperativ die Planmaglucosekonzentrarion bestimmt. Die mittlere Konzentration lag bei 3,8 mmolliter"1. Der niedrigste Wert betrug 2,2 mmol liter"1 trotz Fasten uber 16,5 Stunden. Mdglicherweise sind ambulante Patienten weniger anffiilig fur Hypoglykamie.
Antes de la ciru jia, se evaluaron las concentracioDcs de glucosa en el plasma de 56 ninos de 2 a 16anos de edad tometidos a extracciones dentales bajo anestesia general. La concentracion media era de 3,80 mmol litro "'. El valor mis bajo era de 2,2 mmol litro"1 a pesar de encontrarse de ayunas durante 16,5 h. Es posible que los pacicntes ambulatorios sean menos susctptiblcs a la hipoglicemia. Downloaded from http://bja.oxfordjournals.org/ at University of Lethbridge on September 6, 2015