Pre-operative carbohydrate loading prior to elective caesarean delivery: a randomised controlled trial

A retrospective study of pre-operative fasting times prior to elective or emergency cesarean birth in a large maternity hospital: Lessons to be learned to minimize the fasting time

INTRODUCTION

When managing elective and emergency cesarean births in the same operating room, unpredictable variations in the start times of the cesareans can prolong fasting periods.

METHODS

The fasting times were retrospectively analyzed on 279 consecutive cesarean births at Helsinki University Women's Hospital, Finland, during January-February 2023. The fasting times were compared between the urgency groups and for elective cesareans according to their scheduled order on the operation list. The primary outcome was the difference in the fasting times for food and drink, while the secondary outcome was fasting for both food >12 h and fluids >4 h. The fasting times were compared by one-way ANOVA and chi-squared test, respectively. Dichotomous data are presented as unadjusted odds ratios (OR with 95% CI).

RESULTS

Increasing urgency was associated with shorter fasting times. Fasting times for elective cesareans increased with the scheduled order on the daily list. The mean fasting periods (SD) increased from 10.55 h (SD=1.57) to 14.75 h (SD=2.02) from the first to the third cesarean of the day (p<0.01). The unadjusted odds ratio (95% CI) for fasting of the scheduled cesareans to exceed 12 h for solid foods and 4 h for clear fluids was 6.53 (95% CI: 2.67-15.9, p<0.001), for the third and fourth cesareans compared to the first two cesareans of the day.

CONCLUSIONS

When elective and emergency cesareans are performed by the same team, the woman undergoing the third elective surgery of the day should be advised to have breakfast before 5 a.m. at home. While waiting for the operation, a carbohydrate drink should be offered to limit the fast.

Role of preoperative carbohydrate loading for prevention of perioperative ketoacidosis in elective cesarean delivery

Background and Aims

Starvation of long duration during third trimester of pregnancy is undesirable as it is associated with accelerated fasting leading to hypoglycemia, raised plasma free fatty acid (FFA) levels, and increased plasma/urinary ketones. Carbohydrate (CHO)-rich drinks given preoperatively may ameliorate these deleterious effects. The enhanced recovery after surgery (ERAS) guidelines for perioperative care recommend that oral CHO fluid supplementation 2 h before cesarean delivery may be offered to nondiabetic pregnant women. The aim of the study was to evaluate the role of preoperative oral CHO loading for the prevention of perioperative ketoacidosis in elective cesarean deliveries.

Material and Methods

One hundred and twenty American Society of Anesthesiologists (ASA) II/III parturients undergoing elective cesarean section under subarachnoid block (SAB) were divided into two groups of 60 each after they gave written informed consent. Group A parturients received 400 ml of filtered water 2 h before surgery. Group B parturients received 400 ml of nonparticulate CHO drink 2 h before surgery. The primary outcome was the incidence of ketonuria studied by the dipstick method. Secondary outcomes included hunger and thirst scores, anxiety score, dominant hand grip strength, and the quality of recovery score.

Results

The urine ketone levels were positive (+1) in 8.3% parturients in group A and 1.7% parturients in the CHO group (P value- 0.094). The hunger and thirst scores as well as the modified Beck's anxiety scores were significantly lower in the CHO group (P value- 0.002). Dominant hand grip strength was preserved in both the groups (P value- 0.827). The quality of recovery score was significantly improved in the CHO group (P value- 0.002). No serious adverse effects were noted in either group.

Conclusion

Oral CHO drink is safe when administered 2 h before uncomplicated elective cesarean deliveries. It may have a positive influence on a wide range of perioperative markers of clinical outcome.

Trends in preoperative carbohydrate load practice: A systematic review

BACKGROUND

The preoperative carbohydrate load (PCL) is intended to improve surgical outcomes by reducing the catabolic state induced by overnight fasting. However, there is disagreement on the optimal PCL prescription, leaving local institutions without a standardized PCL recommendation. Results from studies that do not prescribe PCL in identical ways cannot be pooled to draw larger conclusions on outcomes affected by the PCL. The aim of this systematic review is to catalog prescribed PCL characteristics, including timing of ingestion, percentage of carbohydrate contribution, and volume, to ultimately standardize PCL practice.

METHODS

A comprehensive search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials were included if they studied at least one group of patients who were prescribed a PCL and the PCL was described with respect to timing of ingestion, carbohydrate contribution, and total volume.

RESULTS

A total of 67 studies with 6551 patients were included in this systematic review. Of the studies, 49.3% were prescribed PCL on the night before surgery and morning of surgery, whereas 47.8% were prescribed PCL on the morning of surgery alone. The mean prescribed carbohydrate concentration was 13.5% (±3.4). The total volume prescribed was 648.2 ml (±377).

CONCLUSION

Variation in PCL practices prevent meaningful data pooling and outcome analysis, highlighting the need for standardized PCL prescription. Efforts dedicated to the establishment of a gold standard PCL prescription are necessary so that studies can be pooled and analyzed with respect to meaningful clinical end points that impact surgical outcomes and patient satisfaction.

Evidence-based cesarean delivery: preoperative management (part 7)

Preoperative preparation for cesarean delivery is a multistep approach for which protocols should exist at each hospital system. These protocols should be guided by the findings of this review. The interventions reviewed and recommendations made for this review have a common goal of decreasing maternal and neonatal morbidity and mortality related to cesarean delivery. The preoperative period starts before the patient's arrival to the hospital and ends immediately before skin incision. The Centers for Disease Control and Prevention recommends showering with either soap or an antiseptic solution at least the night before a procedure. Skin cleansing in addition to this has not been shown to further decrease rates of infection. Hair removal at the cesarean skin incision site is not necessary, but if preferred by the surgical team then clipping or depilatory creams should be used rather than shaving. Preoperative enema is not recommended. A clear liquid diet may be ingested up to 2 hours before and a light meal up to 6 hours before cesarean delivery. Consider giving a preoperative carbohydrate drink to nondiabetic patients up to 2 hours before planned cesarean delivery. Weight-based intravenous cefazolin is recommended 60 minutes before skin incision: 1-2 g intravenous for patients without obesity and 2 g for patients with obesity or weight ≥80 kg. Adjunctive azithromycin 500 mg intravenous is recommended for patients with labor or rupture of membranes. Preoperative gabapentin can be considered as a way to decrease pain scores with movement in the postoperative period. Tranexamic acid (1 g in 10-20 mL of saline or 10 mg/kg intravenous) is recommended prophylactically for patients at high risk of postpartum hemorrhage and can be considered in all patients. Routine use of mechanical venous thromboembolism prophylaxis is recommended preoperatively and is to be continued until the patient is ambulatory. Music and active warming of the patient, and adequate operating room temperature improves outcomes for the patient and neonate, respectively. Noise levels should allow clear communication between teams; however, a specific decibel level has not been defined in the data. Patient positioning with left lateral tilt decreases hypotensive episodes compared with right lateral tilt, which is not recommended. Manual displacers result in fewer hypotensive episodes than left lateral tilt. Both vaginal and skin preparation should be performed with either chlorhexidine (preferred) or povidone iodine. Placement of an indwelling urinary catheter is not necessary. Nonadhesive drapes are recommended. Cell salvage, although effective for high-risk patients, is not recommended for routine use. Maternal supplemental oxygen does not improve outcomes. A surgical safety checklist (including a timeout) is recommended for all cesarean deliveries.

Association between pregnant women fasting duration and neonatal hypoglycemia: A prospective cohort study

OBJECTIVE

To evaluate the association between maternal fasting time before delivery and the occurrence of hypoglycemia in neonates immediately after birth.

METHODS

This prospective single-center cohort study included pregnant women who delivered at the study institution between October 2021 and January 2023 and their neonates. The primary outcome was the incidence of neonatal hypoglycemia after birth, defined as a blood glucose level less than 47 mg/dL. Fasting time was categorized into quartiles, and the association between maternal fasting time and neonatal hypoglycemia was investigated. The crude or adjusted odds ratios of maternal fasting time for neonatal hypoglycemia were calculated using logistic regression analysis.

RESULTS

The study included 663 pregnant women and 696 neonates. Compared with the reference group with a short fasting time of 4.3 h or less, the adjusted odds ratios for neonatal hypoglycemia were 1.47 (95% confidence interval [CI] 0.70-3.20) for middle fasting time (4.3-9.8 h), 4.05 (95% CI 2.02-8.56) for long fasting time (9.8-14.6 h), and 4.99 (95% CI 2.59-10.25) for very long fasting time (>14.6 h). In the subgroup analysis, the association between maternal fasting time and neonatal hypoglycemia showed different trends according to the mode of delivery.

CONCLUSION

Maternal fasting time over 9-10 h before delivery was associated with the occurrence of neonatal hypoglycemia. Obstetrical management, considering not only maternal safety but also neonatal hypoglycemia prevention, is required.

Effects of Preoperative Oral Carbohydrate on Perioperative Maternal Outcomes Undergoing Cesarean Section: A Systematic Review and Meta-Analysis

Purpose

Preoperative oral carbohydrate (CHO) is a rapid postoperative rehabilitation protocol that improves perioperative outcomes and is widely used in adult surgical patients. However, pregnant women are excluded because of the possibility of aspiration due to delayed gastric emptying. This meta-analysis was conducted to evaluate the efficacy of preoperative oral CHO in elective cesarean section.

Methods

PubMed, Embase, Web of Science, and the Cochrane Library were searched from inception to July 2023. Randomized controlled trials were included. The risk of bias was assessed using the Cochrane tool. Risk ratios and 95% confidence intervals were calculated. Meta-analysis was performed using random-effects models to estimate risk ratios and mean differences (MDs) with 95% confidence intervals (CIs). The outcomes included thirst and hunger scores, incidence of vomiting and nausea, time to flatus, and homeostatic model assessment of insulin resistance (HOMA-IR).

Results

A total of nine studies with 1211 patients were included in the analysis. The levels of thirst and hunger were evaluated using a 10-point visual analog scale, with 0 representing the best and 10 representing the worst. The severity of hunger (weighted mean difference (WMD: -2.34, 95% CI: -3.13 to -1.54), time to flatus (WMD: -3.51 hours, 95% CI: -6.85 to -0.17), and HOMA-IR (WMD: -1.04, 95% CI: -1.31 to -0.77) were significantly lower in the CHO group compared to the control group. However, there were no significant differences in the severity of thirst or the incidence of vomiting and nausea between the CHO and control groups.

Conclusion

Preoperative oral CHO during cesarean section alleviates thirst and hunger, shortens the time of postoperative flatus, and reduces HOMA-IR. However, the available evidence is insufficient to reach a clear consensus on the benefits or harms of preoperative oral CHO during cesarean section. Therefore, it is premature to make a definitive recommendation for or against its routine use.

Preoperative Oral Carbohydrate (CHO) Supplementation Is Beneficial for Clinical and Biochemical Outcomes in Patients Undergoing Elective Cesarean Delivery under Spinal Anaesthesia-A Randomized Controlled Trial

BACKGROUND

Preoperative fasting and surgery cause metabolic stress, insulin resistance with ketosis, and postoperative nausea and vomiting (PONV). Oral carbohydrate loading strategy (CHO) improves outcomes in labor and general surgery. We aimed to compare the effectiveness of CHO with standard fasting in patients undergoing elective cesarean delivery (CD) under spinal anesthesia.

METHODS

A single-center, parallel, prospective randomized controlled trial (RCT) was conducted in a tertiary university obstetrics department at Pomeranian Medical University in Szczecin, Poland. Patients were randomly assigned (1:1 ratio) to the CHO group (oral carbohydrate 2 h before elective CD, n = 75) or the SF group (control-standard fasting, n = 73). The main outcome measures were incidence and severity of PONV at 6 and 24 h after CD, time to the first peristalsis, time to first bowel movement, and biochemical parameters indicating ketosis in mothers and their children.

RESULTS

A total of 148 adult females with singleton pregnancies undergoing elective CD under spinal anesthesia (ASA I and II) were included in the final analysis. At 24 h after CD, 8.0% from the CHO group vs. 20.55% reported three or more episodes of vomiting or dry retching as compared to patients in the SF group (p = 0.041). Preoperative CHO supplementation decreased preoperative feelings of hunger (p < 0.001) and thirst (p < 0.001). Laboratory results in the CHO group showed higher plasma pH (p = 0.001) and glucose (p < 0.001), lower F2-isoprostane in plasma (p = 0.049) and urine (p = 0.018), lower urine F2-isoprostane/creatinine ratio (p = 0.045) than in the SF group. HOMA-IR (p < 0.001) and lactate (p < 0.001) were higher in the CHO group than in the control group.

CONCLUSIONS

There was no significant difference in the incidence or severity of early PONV at 6 h. The incidence of vomiting or dry retching at 24 h after cesarean delivery was lower in the CHO group as compared to standard starvation, but the combined results of PONV frequency and severity on the Wengritzky scale did not differ between the two study groups. Preoperative CHO supplementation decreased preoperative feelings of hunger and thirst, enhancing the comfort of pregnant women.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04069806.

2023 American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting: Carbohydrate-containing Clear Liquids with or without Protein, Chewing Gum, and Pediatric Fasting Duration-A Modular Update of the 2017 American Society of Anesthesiologists Practice Guidelines for Preoperative Fasting

These practice guidelines are a modular update of the "Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy patients undergoing elective procedures." The guidance focuses on topics not addressed in the previous guideline: ingestion of carbohydrate-containing clear liquids with or without protein, chewing gum, and pediatric fasting duration.

Effect of enhanced recovery after surgery for elective cesarean deliveries on neonatal outcomes

OBJECTIVE

To evaluate the impact of initiation of an enhanced recovery after cesarean delivery (ERAC) protocol for elective cesarean delivery (CD) on neonatal outcomes.

STUDY DESIGN

We performed a retrospective analysis of elective CD at ≥39 weeks gestational age between September 2014 and August 2018 at a single institution before and after ERAC protocol implementation. Our primary outcome was composite neonatal complication rate and secondary outcome was rate of breastfeeding. We performed univariate analyses to detect differences in outcomes between the pre-ERAC and post-ERAC groups.

RESULTS

We included 362 neonates born via elective CD before (n = 135) and after (n = 227) ERAC implementation. The post-ERAC group experienced fewer composite neonatal complications (33.0% vs. 47.4%, p = 0.009) and greater breastfeeding rates (80.2% vs. 67.4%, p = 0.009) compared to the pre-ERAC group.

CONCLUSION

ERAC protocol implementation does not negatively impact neonates and may benefit both mother and baby.

The impact of oral carbohydrate-rich supplement taken two hours before caesarean delivery on maternal and neonatal perioperative outcomes -- a randomized clinical trial

Background

To evaluate the impact of oral carbohydrate-rich (Ch-R) supplement taken 2 hours before an elective caesarean delivery (CD) on maternal and neonatal perioperative outcomes.

Methods

Ninety pregnant women undergoing elective CD were randomized into the Ch-R group, placebo group and fasting group equally. Participants’ blood was drawn at three time points, before intervention, immediately after and 1 day after the surgery to measure maternal and neonatal biochemical indices. Meanwhile women’s perioperative symptoms and signs were recorded.

Results

Eighty-eight pregnant women were finally included in the study. Women who had drunk Ch-R supplement had lower postoperative insulin level (β = − 3.50, 95% CI − 5.45 to − 1.56), as well as postoperative HOMA-IR index (β = − 0.74, 95% CI − 1.15 to − 0.34), compared with women who had fasted. Additionally, neonates of mothers who were allocated in the Ch-R group also had a higher glucose level, compared with neonates of mothers in the fasting group (β = 0.40, CI 0.17 to 0.62).

Conclusion

Oral Ch-R solution administered 2 hours before an elective CD may not only alleviate maternal postoperative insulin resistance, but also comfort women’s preoperative thirst and hunger, compared to fasting. Additionally, it may increase neonatal glucose level as well.

Trial registration

Chinese Clinical Trial Registry, ChiCTR2000033163.

Data of Registration: 2020-5-22.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04155-z.

Incidence of urinary ketosis and the effect of carbohydrate drink supplementation during fasting for elective caesarean section: Audit

Elective lower segment caesarean section patients are routinely instructed to fast from food for 6h before surgery, with clear fluids up until 2h before surgery. We conducted an audit examining the true fasting times of mothers undergoing an elective caesarean section and the incidence of urinary ketones before and after introducing a preop carbohydrate drink (Nutricia preOp 400ml) to be administered to all patients at 6am on the day of surgery. We audited 50 patients prior to introducing the preop carbohydrate drink and 54 patients after the introduction of a carbohydrate drink. We found the mean fasting time from last caloric intake was reduced from 13h 35min to 5h 5min after the introduction of a preoperative carbohydrate drink. We found that the incidence of urinary ketones was 40.4% prior to the introduction of a preoperative carbohydrate drink and 38.3% after the introduction of a preop drink (p = 1). If fasting times were limited to under 4h, the incidence of urinary ketones is 10%. Our audit demonstrates that reducing preoperative fasting times is possible and preventing metabolic derangements may be possible, requiring an approach targeted at keeping fasting times to a minimum.