A randomised controlled trial of fluid pre-loading before low dose epidural analgesia for labour

Consensus on the Southeast Asian management of hypotension using vasopressors and adjunct modalities during cesarean section under spinal anesthesia

BACKGROUND AND AIMS

This consensus statement presents a comprehensive and evidence-based set of guidelines that modify the general European or US guidelines for hypotension management with vasopressors during cesarean delivery. It is tailored to the Southeast Asian context in terms of local human and medical resources, health system capacity, and local values and preferences.

METHODS AND RESULTS

These guidelines were prepared using a methodological approach. Two principal sources were used to obtain the evidence: scientific evidence and opinion-based evidence. A team of five anesthesia experts from Vietnam, the Philippines, and Thailand came together to define relevant clinical questions; search for literature-based evidence using the MEDLINE, Scopus, Google Scholar, and Cochrane libraries; evaluate existing guidelines; and contextualize recommendations for the Southeast Asian region. Furthermore, a survey was developed and distributed among 183 practitioners in the captioned countries to gather representative opinions of the medical community and identify best practices for the management of hypotension with vasopressors during cesarean section under spinal anesthesia.

CONCLUSIONS

This consensus statement advocates proactive management of maternal hypotension during cesarean section after spinal anesthesia, which can be detrimental for both the mother and fetus, supports the choice of phenylephrine as a first-line vasopressor and offers a perspective on the use of prefilled syringes in the Southeast Asian region, where factors such as healthcare features, availability, patient safety, and cost should be considered.

The Optimal Pain Management Approach for a Laboring Patient: A Review of Current Literature

There is a general agreement that a patient in labor should be given the option to have an epidural block for pain management. Despite this consensus, there are differences in practice patterns as to when to initiate an epidural and how to minimize its impact on the duration and outcome of a patient’s labor. A review of the literature suggests epidural analgesia does prolong stages one and two of labor, but not significantly. Cesarean delivery rates are not affected by the early initiation of epidural analgesia. The use of various adjuvants such as opioids, clonidine, and neostigmine in conjunction with local anesthetics solution can significantly reduce the severity of motor blockade and the need for assisted vaginal delivery.

Randomized clinical trial of fluid and salt restriction compared with a controlled liberal regimen in elective gastrointestinal surgery

Background

Excessive intravenous fluid prescription may play a causal role in postoperative complications following major gastrointestinal resectional surgery. The aim of this study was to investigate whether fluid and salt restriction would decrease postoperative complications compared with a more modern controlled liberal regimen.

Methods

In this observer-blinded single-site randomized clinical trial consecutive patients undergoing major gastrointestinal resectional surgery were randomized to receive either a liberal control fluid regimen or a restricted fluid and salt regimen. The primary outcome was postoperative complications of grade II and above (moderate to severe).

Results

Some 240 patients (194 colorectal resections and 46 oesophagogastric resections) were enrolled in the study; 121 patients were randomized to the restricted regimen and 119 to the control (liberal) regimen. During surgery the control group received a median (interquartile range) fluid volume of 2033 (1576–2500) ml and sodium input of 282 (213–339) mmol, compared with 1000 (690–1500) ml and 142 (93–218) mmol respectively in the restricted group. There was no significant difference in major complication rate between groups (38·0 and 39·0 per cent respectively). Median (range) hospital stay was 8 (3–101) days in the controls and 8 (range 3–76) days among those who received restricted fluids. There were four in-hospital deaths in the control group and two in the restricted group. Substantial differences in weight change, serum sodium, osmolality and urine : serum osmolality ratio were observed between the groups.

Conclusion

There were no significant differences in major complication rates, length of stay and in-hospital deaths when fluid restriction was used compared with a more liberal regimen. Registration number: ISRCTN39295230 (http://www.controlled-trials.com).

Maternal pulse pressure at admission is a risk factor for fetal heart rate changes after initial dosing of a labor epidural: a retrospective cohort study

OBJECTIVE

To examine low maternal admission pulse pressure (PP) as a risk factor for new onset postepidural fetal heart rate (FHR) abnormalities.

STUDY DESIGN

Retrospective cohort study of nulliparous, singleton, vertex-presenting women admitted to labor and delivery after 37 0/7 weeks that received an epidural during labor. Women with a low admission PP were compared with those with a normal admission PP. The primary outcome was new onset FHR abnormalities defined as recurrent late or prolonged FHR decelerations in the first hour after initial dosing of a labor epidural.

RESULTS

New onset FHR abnormalities, defined as recurrent late decelerations and/or prolonged decelerations, occurred in 6% of subjects in the normal PP cohort compared with 27% in the low PP cohort (odds ratio, 5.6; 95% confidence interval, 2.1-14.3; P < .001). A multivariate logistic regression analysis generated an adjusted odds ratio of 28.9 (95% confidence interval, 3.7-221.4; P < .001).

CONCLUSION

New onset FHR abnormalities after initial labor epidural dosing occur more frequently in women with a low admission PP than those with a normal admission pulse. Admission PP appears to be a novel predictor of new onset postepidural FHR abnormalities.

A randomized controlled trial of the effect of intrapartum intravenous fluid management on breastfed newborn weight loss

OBJECTIVE

To determine the effect of conservative versus usual intrapartum intravenous (IV) fluid management for low-risk women receiving epidural analgesia on weight loss in breastfed newborns.

DESIGN

A randomized controlled trial.

SETTING

A tertiary perinatal center in a large urban setting.

SAMPLE

Women experiencing uncomplicated pregnancies who planned to have epidural analgesia and to breastfeed.

METHODS

Healthy pregnant women were randomized to receive an IV epidural preload volume of <500 mLs continuing at an hourly rate of 75-100 mL/h (conservative care) or an epidural preload volume of ≥500 mLs and an hourly rate >125 mL/h (usual care). The primary study outcome was breastfed newborn weight loss >7% prior to hospital discharge. Secondary study outcomes included breastfeeding exclusivity, referral to outpatient breastfeeding clinic support, and delayed discharge. Other outcomes were admission to the neonatal intensive care unit and cord blood pH <7.25.

RESULTS

Two hundred women participated (100 in the conservative care and 100 in the usual care groups). Forty-eight of 100 infants in the usual care group and 44 of the 100 infants in the conservative care group lost >7% of their birth weight prior to discharge, p < 0.52 RR 0.92 [0.68-1.24].

CONCLUSION

A policy of restricted IV fluids did not affect newborn weight loss. Women and their care providers should be reassured that the volumes of IV fluid <2500 mLs are unlikely to have a clinically meaningful effect on breastfed newborn weight loss >7%. Exploratory analyses suggest that breastfed newborn weight loss increases when intrapartum volumes infused are >2500 mLs. Care providers are encouraged to consider volumes of IV fluid infused intrapartum as a factor that may have contributed to early newborn weight loss in the first 48 h of life.

Which goal for fluid therapy during colorectal surgery is followed by the best outcome: near-maximal stroke volume or zero fluid balance?

BACKGROUND

We aimed to investigate whether fluid therapy with a goal of near-maximal stroke volume (SV) guided by oesophageal Doppler (ED) monitoring result in a better outcome than that with a goal of maintaining bodyweight (BW) and zero fluid balance in patients undergoing colorectal surgery.

METHODS

In a double-blinded clinical multicentre trial, 150 patients undergoing elective colorectal surgery were randomized to receive fluid therapy after either the goal of near-maximal SV guided by ED (Doppler, D group) or the goal of zero balance and normal BW (Zero balance, Z group). Stratification for laparoscopic and open surgery was performed. The postoperative fluid therapy was similar in the two groups. The primary endpoint was postoperative complications defined and divided into subgroups by protocol. Analysis was performed by intention-to-treat. The follow-up was 30 days. The trial had 85% power to show a difference between the groups.

RESULTS

The number of patients undergoing laparoscopic or open surgery and the patient characteristics were similar between the groups. No significant differences between the groups were found for overall, major, minor, cardiopulmonary, or tissue-healing complications (P-values: 0.79; 0.62; 0.97; 0.48; and 0.48, respectively). One patient died in each group. No significant difference was found for the length of hospital stay [median (range) Z: 5.00 (1-61) vs D: 5.00 (2-41); P=0.206].

CONCLUSIONS

Goal-directed fluid therapy to near-maximal SV guided by ED adds no extra value to the fluid therapy using zero balance and normal BW in patients undergoing elective colorectal surgery.

Progress in analgesia for labor: focus on neuraxial blocks

Neuraxial analgesia is widely accepted as the most effective and the least depressant method of providing pain relief in labor. Over the last several decades neuraxial labor analgesia techniques and medications have progressed to the point now where they provide high quality pain relief with minimal side effects to both the mother and the fetus while maximizing the maternal autonomy possible for the parturient receiving neuraxial analgesia. The introduction of the combined spinal epidural technique for labor has allowed for the rapid onset of analgesia with minimal motor blockade, therefore allowing the comfortable parturient to ambulate. Patient-controlled epidural analgesia techniques have evolved to allow for more flexible analgesia that is tailored to the individual needs of the parturient and effective throughout the different phases of labor. Computer integrated systems have been studied to provide seamless analgesia from induction of neuraxial block to delivery. New adjuvant drugs that improve the effectiveness of neuraxial labor analgesia while decreasing the side effects that may occur due to high dose of a single drug are likely to be added to future labor analgesia practice. Bupivacaine still remains a popular choice of local anesthetic for labor analgesia. New local anesthetics with less cardiotoxicity have been introduced, but their cost effectiveness in the current labor analgesia practice has been questioned.

Fluid therapy for the surgical patient

Perioperative fluid therapy is the subject of much controversy, and the results of the clinical trials investigating the effect of fluid therapy on outcome of surgery seem contradictory. The aim of this chapter is to review the evidence behind current standard fluid therapy, and to critically analyse the trials examining the effect of fluid therapy on outcome of surgery. The following conclusions are reached: current standard fluid therapy is not at all evidence-based; the evaporative loss from the abdominal cavity is highly overestimated; the non-anatomical third space loss is based on flawed methodology and most probably does not exist; the fluid volume accumulated in traumatized tissue is very small; and volume preloading of neuroaxial blockade is not effective and may cause postoperative fluid overload. The trials of 'goal-directed fluid therapy' aiming at maximal stroke volume and the trials of 'restricted intravenous fluid therapy' are also critically evaluated. The difference in results may be caused by a lax attitude towards 'standard fluid therapy' in the trials of goal-directed fluid therapy, resulting in the testing of various 'standard fluid regimens' versus 'even more fluid'. Without evidence of the existence of a non-anatomical third space loss and ineffectiveness of preloading of neuroaxial blockade, 'restricted intravenous fluid therapy' is not 'restricted', but rather avoids fluid overload by replacing only the fluid actually lost during surgery. The trials of different fluid volumes administered during outpatient surgery confirm that replacement of fluid lost improves outcome. Based on current evidence, the principles of 'restricted intravenous fluid therapy' are recommended: fluid lost should be replaced and fluid overload should be avoided.

Issues of consent for regional analgesia in labour: a survey of obstetric anaesthetists

Anaesthetists are legally obliged to obtain consent and inform patients of material risks prior to administering regional analgesia in labour. We surveyed consultant members of the Australian and New Zealand College of Anaesthetists with a special interest in obstetric anaesthesia, in order to identify and compare which risks of regional analgesia they report discussing with women prior to and during labour. We also asked about obstetric anaesthetists' beliefs about informed consent, the type of consent obtained and its documentation. Of 542 questionnaires distributed, 291 responses (54%) were suitable for analysis. The five most commonly discussed risks were post dural puncture headache, block failure, permanent neurological injury, temporary leg weakness and hypotension. Obstetric anaesthetists reported discussing a mean of 8.0 (SD 3.8) and 10 (SD 3.8) risks in the labour and antenatal settings respectively. Nearly 20% of respondents did not rank post dural puncture headache among their top five most important risks for discussion. Seventy percent of respondents indicated that they believe active labour inhibits a woman's ability to give 'fully informed consent'. Over 80% of respondents obtain verbal consent and 57 (20%) have no record of the consent or its discussion. Obstetric anaesthetists reported making a considerable effort to inform patients of risks prior to the provision of regional analgesia in labour. Verbal consent may be appropriate for labouring women, using standardized forms that serve as a reminder of the risks, and a record of the discussion. Consensus is required as to what are the levels of risk from regional analgesia in labour.

Neuraxial analgesia and fetal bradycardia

PURPOSE OF REVIEW

To review the most recent data on labor analgesia and the risk of fetal heart rate changes.

RECENT FINDINGS

Fetal heart rate changes are more common with intrathecal opioids, especially when high doses are used. Intrathecal clonidine seems to increase the risk of hypotension and fetal heart rate changes. Intravenous fluid preloading is useful in high-dose labor epidural analgesia, but its use remains controversial with low-dose techniques of epidural analgesia. Despite the potential of neuraxial analgesia to induce fetal bradycardia, neonatal outcome is usually reassuring.

SUMMARY

Despite the potential of neuraxial analgesia to cause fetal heart rate problems, neuraxial analgesia is the most effective and safest form of labor analgesia. Specific techniques of labor analgesia, such as high-dose spinal opioids or intrathecal clonidine, must be avoided based on the most recent evidence. Maternal and neonatal outcome is good following regional analgesia.

Prophylactic intravenous preloading for regional analgesia in labour

BACKGROUND

Reduced uterine blood flow from maternal hypotension may contribute to fetal heart rate changes which are common following regional analgesia (epidural or spinal or combined spinal-epidural (CSE)) during labour. Intravenous fluid preloading may help to reduce maternal hypotension but using lower doses of local anaesthetic, and opioid only blocks, may reduce the need for preloading.

OBJECTIVES

To assess the effects of prophylactic intravenous fluid preloading before regional analgesia during labour on maternal and fetal well-being.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (19 February 2004).

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing prophylactic intravenous preloading before regional analgesia during labour with a control group (dummy or no preloading).

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied eligibility criteria, assessed trial quality and extracted data.

MAIN RESULTS

Six studies are included (473 participants). In one epidural trial using high-dose local anaesthetic, preloading with intravenous fluids was shown to counteract the hypotension which frequently follows traditional epidural analgesia (relative risk (RR) 0.07, 95% confidence interval (CI) 0.01 to 0.53; 102 women). This trial was also associated with a reduction in fetal heart rate abnormalities (RR 0.36, 95% CI 0.16 to 0.83; 102 women); no differences were detected in other perinatal and maternal outcomes for this trial and another high-dose epidural trial. In the two epidural low-dose anaesthetic trials, no significant difference in maternal hypotension was found (RR 0.73, 95% CI 0.36 to 1.48; 260 women), although they were underpowered to detect less than a very large effect. No significant differences were seen between groups in these trials for fetal heart rate abnormalities (RR 0.64, 95% CI 0.39 to 1.05; 233 women). In the two CSE trials, no differences were reported between preloading and no preloading groups. In the spinal/opioid trial, the RR for hypotension was 0.89, 95% CI 0.43 to 1.83 (40 women) and 0.70, 95% CI 0.36 to 1.37 for fetal heart rate abnormalities (32 women). In the opioid only study (30 women), there were no instances of hypotension or fetal heart rate abnormalities in either group.

REVIEWERS' CONCLUSIONS

Preloading prior to traditional high-dose local anaesthetic blocks may have some beneficial fetal and maternal effects in healthy women. Low-dose epidural and CSE analgesia techniques may reduce the need for preloading. The studies reviewed were too small to show whether preloading is beneficial for women having regional analgesia during labour using the lower-dose local anaesthetics or opioids. Further investigation of low-dose epidural or CSE (including opioid only) blocks, and the risks and benefits of intravenous preloading for women with pregnancy complications, is required.