Lactic acidosis complicating treatment of ketosis of labour

Interventions for ketosis during labour

BACKGROUND

In labour, ketosis (the elevation of ketone bodies in the blood) is a common occurrence, due to increased physical stress, which is often compounded by reduced oral intake. The effect of ketosis on the mother and baby during labour is not clear, therefore, there is uncertainty as to whether ketosis is a normal physiological response or whether women with ketosis in labour require intervention (such as intravenous fluids or increased oral intake) for maternal and infant wellbeing. This uncertainty has resulted in differences in opinion and practice by those providing care for women in labour.

OBJECTIVES

To assess the effects on maternal, fetal and neonatal outcomes of intravenous fluids or increased oral intake administered to women in labour for the treatment of ketosis compared with no intervention (defined as no oral intake, ice chips only, or oral intake on demand) and to also assess the effects of different types of intravenous fluids administered.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2008), CENTRAL (The Cochrane Library 2007, Issue 2), MEDLINE (1950 to January 2007), EMBASE (1988 to January 2007) and CINAHL (1982 to 2007).

SELECTION CRITERIA

All published and unpublished randomised trials in which additional oral intake or intravenous fluids, or both, were used for the treatment of women with ketosis in labour.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed potentially eligible trials. The authors sought additional information on trial methods and outcome data to enable consideration of eligibility of studies. However, at the time of the review, no information was received.

MAIN RESULTS

We identified six trials as potentially eligible for inclusion in this review. All six studies were excluded. Therefore no trials are included in this review.

AUTHORS' CONCLUSIONS

There is no information on which to base practice in the treatment of women with ketosis during labour. Further research is required to identify more clearly the association between ketosis in labour and pregnancy outcome. Future trials should examine the effects of no interventions and different types of intravenous and oral fluids on these clinically important outcomes, and include women's perception and satisfaction with care during labour and birth.

Eating in labour. A randomised controlled trial assessing the risks and benefits

The aim of this study was to determine whether permitting women in labour to eat a light diet would: (i) alter their metabolic profile, (ii) influence the outcome of labour, and (iii) increase residual gastric volume and consequent risk of pulmonary aspiration. Women were randomised to receive either a light diet (eating group, n = 48) or water only (starved group, n = 46) during labour. The light diet prevented the rise in plasma beta-hydroxybutyrate (p = 2.3 x 10(-5)) and nonesterified fatty acids (p = 9.3 x 10(-7)) seen in the starved group. Plasma glucose (p = 0.003) and insulin (p = 0.017) rose in the eating group but there was no difference in plasma lactate (p = 0.167) between the groups. There were no differences between the groups with respect to duration of first or second stage of labour, oxytocin requirements, mode of delivery, Apgar scores or umbilical artery and venous blood samples. Relative gastric volumes estimated by ultrasound measurement of gastric antral cross-sectional area were larger (p = 0.001) in the eating group. This was supported by the observation that those from this group who vomited, vomited significantly larger volumes than those in the starved group (p = 0.001). We conclude that eating in labour prevents the development of ketosis but significantly increases residual gastric volume.

Neonatal hypoglycemia following maternal glucose infusion prior to delivery

Intravenous glucose therapy to mother prior to delivery significantly affects glucose and insulin homeostasis in fetus and newborn infants. Specifically, the infants show hyperglycemia, and hyperinsulinism at birth, and are predisposed to hypoglycemia in the first few hours of life. In this paper we have focussed attention on the clinical significance of these changes and suggest some remedial measures, in light of our own research.

A comparison of the effects of four intravenous solutions for the treatment of ketonuria during labour

Forty women in whom ketonuria was detected during the first stage of labour were allocated randomly to intravenous treatment with one litre of either normal saline, Hartmann's solution, 5% dextrose or 10% dextrose. The solutions were administered over 1 h and blood was taken immediately beforehand and thereafter at 30-min intervals for 90 min to assess their effect on intermediary metabolism, plasma osmolality and acid-base status. Although both the 5 and 10% dextrose infusions caused a rapid decline in whole blood D-3-hydroxybutyrate concentrations, they also produced pathological degrees of maternal hyperglycaemia and hyperinsulinaemia and a marked elevation in the mean blood lactate and pyruvate concentrations. Administration of 10% dextrose was also associated with a significant increase in serum osmolality. Hartmann's solution produced significantly higher mean whole blood lactate and pyruvate concentrations than did normal saline. There was a significant increase in the venous base deficit in the group infused with 10% dextrose, indicating that the buffering capacity of the blood had been exceeded. It is concluded that rapid infusions of dextrose or Hartmann's solution should not be administered during labour. Normal saline should be used for rehydration and if dextrose therapy is deemed necessary the dose administered should not exceed physiological requirements.

Effect of glucose infusion on the maternal and fetal acid-base equilibrium during labor

The effect of hypertonic glucose infusion on the maternal and fetal acid-base equilibrium was studied in 20 clinically normal parturients and their concepts. Samples of maternal peripheral venous blood and fetal capillary blood were collected before and after intravenous infusion of 25 g of glucose into the mother at 15-minute intervals. No significant alterations in the parameters of the maternal acid-base equilibrium were observed. On the fetal ide, a significant decrease in pO2 at intervals of 30, 45 and 60 minutes after glucose infusion (fig. 1), and an increase of total CO2 after 60 minutes (fig. 2) were observed. These findings did not permit us to state that glucose infusion may be responsible for the alterations found, since it is known that as labor progresses, PO2 tends to decrease while total CO2 tends to increase. On the other hand, an increase in glycemic levels is known to stimulate the rate of glucose consumption at the expense of its aerobic metabolism, by reducing the oxygen level and increasing CO2, the final products of this glucolytic pathway.

Liver function and lactate metabolism in the ill surgical patient

Liver function and lactate metabolism were investigated in non-shocked, severely ill surgical patients. Fasting venous blood lactate concentration was increased and plasma liver function tests were abnormal in ill patients compared with controls. Ill patients were glucose-intolerant and blood lactate changes following intravenous glucose infusion were similar in both ill and control patients. Blood lactate half-life was increased in ill patients following a sodium L-lactate infusion, suggesting that the increased fasting lactate concentration may have been due to decreased hepatic removal rather than to increased peripheral production of lactate.

Metabolic effects of constant hypertonic glucose infusion in well-oxygenated fetuses

In order to investigate the metabolic effects of a constant hypertonic glucose infusion in well-oxygenated fetuses, ten experiments were carried out in nine long-term experiments in fetal lambs. It appeared that a constant hypertonic glucose infusion did not significantly affect the fetal blood gases, pH, and plasma lactate levels when fetal glucose was kept below 150 mg. per 100 ml. It was also demonstrated that glucose infusions significantly increased the fetal lactate levels and decreased the blood pH when fetal plasma glucose was over 150 mg. per 100 ml. However, there was no decrease in fetal PO2 and pco2 until fetal glucose reached values over 300 mg. per 100 ml. These studies suggest that constant hypertonic glucose infusion does not improve fetal blood gases or pH and that fetal hyperglycemia over 300 mg. per 100 ml. produces severe metabolic acidosis.

Biochemical changes in prolonged labour in the tropics

Serum electrolytes, creatinine, urea and urine osmolality were estimated in 25 healthy pregnant women at term, 25 women in early normal labour, and 25 healthy parturients in prolonged labour. A statistically significant fall in serum potassium was found in early labour with a further significant fall in prolonged labour. Bicarbonate changes followed the same pattern of a progressive fall. Sodium fell slowly, reaching significant levels only in prolonged labour and chloride fell even more slowly. There was a conspicuous or significant rise in serum urea with a smaller, not significant rise in creatinine. The rapid insensible loss of water in tropical areas was reflected in the rise in serum urea while homeostatic mechanisms maintained a slower fall in sodium and chloride by renal conservation.

Changes in plasma lactate, phosphate and uric acid during postoperative carbohydrate infusion

Eighteen patients undergoing elective abdominal surgery had pre- and postoperative carbohydrate infusion tests with glucose, fructose or sorbitol. All three substrates produced significant hyperlactataemia postoperatively, the elevations of plasma lactate with fructose and sorbitol infusion being significantly greater than with glucose. Plasma uric acid was unchanged but there were moderate falls in plasma phosphate postoperatively. Intravenous nutritional regimens containing fructose and sorbitol may potentiate the development of harmful metabolic acidoses in 'at risk' patients and should always be used cautiously. Glucose is the carbohydrate calorie source of choice.