Effect of amino acid infusion during cesarean delivery on newborn temperature: a randomized controlled trial

Abstract

Background: The effect of maternal amino acid (AA) infusion before and during cesarean delivery on neonatal temperature remains unknown. We hypothesized that thermogenic effects of AA metabolism would help maintain body temperature of newborn babies and their mothers.

Methods: Seventy-six parturients scheduled for elective singleton term cesarean delivery were equally randomized to receive intravenous 200 ml of AA or placebo approximately 1 h before subarachnoid block (infusion rate:100 ml/h). The primary outcome was the newborn rectal temperature at 0, 5 and 10 min after birth. The secondary outcomes included the maternal rectal temperature at six time-points: T0 = before starting study solution infusion, T1 = 30 min after starting infusion, T2 = one hour after starting infusion, T3 = during spinal block, T4 = half an hour after spinal block, T5 = at the time of birth and T6 = at the end of infusion, as well as maternal thermal discomfort and shivering episodes.

Results: There were no differences in newborn temperature between the two groups at any of the time-points (intervention-time-interaction effect, P = 0.206). The newborn temperature (mean [95%CI] °C) at birth was 37.5 [37.43-37.66] in the AA and 37.4 [37.34-37.55] in the placebo group. It showed a significant (P < 0.001) downward trend at 5 and 10 min after birth (time effect) in both groups. One neonate in the AA and five in the placebo group were hypothermic (temperature < 36.5 °C) (P = 0.20). There was a significant difference in the maternal temperature at all time points between the two groups (Intervention-time interaction effect, P < 0.001). However, after adjustment for multiplicity, the difference was significant only at T6 (P = 0.001). The mean difference [95%CI] in temperature decline from baseline (T0) till the end of infusion (T6) between the two groups was - 0.39 [- 0.55;- 0.22] °C (P < 0.0001). Six mothers receiving placebo and none receiving AA developed hypothermia (temperature < 36 °C) (P = 0.025). Maternal thermal discomfort and shivering episodes were unaffected by AA therapy.

Conclusions: Under the conditions of this study, maternal AA infusion before and during spinal anesthesia for cesarean delivery did not influence the neonatal temperature within 10 min after birth. In addition, the maternal temperature was only maintained at two hours of AA infusion.

Trial registration: ClinicalTrials.government, Identifier NCT02575170 . Registered on 10th April, 2015 - Retrospectively registered.

Keywords: Amino acid; Cesarean delivery; Hypothermia; Newborn; Spinal anesthesia.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1

Consort flow chart

Fig. 2

Newborn temperature (mean and CI bars) at 0, 5 and 10-min after birth. Repeated-measures ANOVA revealed a significant decline in temperature in the both groups at 5 and 10 min after birth (Time effect, ◆P < 0.001). However, there was no significant difference in temperature between the AA group and the placebo group (Intervention effect, P = 0.092; Intervention-time interaction effect, P = 0.206)

Fig. 3

Shows the trend of maternal body temperature (mean and CI bars) at six time-points: T0 = before starting study solution infusion, T1 = 30 min after starting infusion, T2 = one hour after starting infusion, T3 = during spinal block, T4 = half an hour after spinal block, T5 = at the time of birth and T6 = at the end of infusion. The body temperature increased from baseline during AA infusion until the subarachnoid block procedure (T3). Placebo group did not show any change in body temperature till the T3 time point. After spinal anesthesia body temperature showed a steady decline in both groups, however, it remained higher in the AA group than the placebo group. Linear mixed model analysis revealed that the temperature differences from baseline in the AA group were significant at all time points except at T4 (Time effect, ◆P < 0.005). In the placebo group, the decline in maternal temperature from baseline was observed after spinal block at three time points T4, T5 and T6 (time effect ◊P < 0.005). A significant difference in temperature between the two groups was observed at all time points (Intervention effect, P = 0.021 at T1, P = 0.003 at T2, P < 0.001 at T3, P = 0.001 at T4, P < 0.001 at T5, and P < 0.001 at T6; Intervention-time interaction effect, P < 0.001). After adjustment for multiplicity (P = 0.007), the difference in the maternal temperature between the two groups was only significant at T6 (×P = 0.001)