Reply to Akça, B.; Bilotta, F. Time and Type of Administered Fluids during Cesarean Section Might Not Matter for Hemodynamic Outcomes, but There Are Significant Patient Safety Concerns Regarding Colloid Use in Parturients. Comment on "Theodoraki et al. Colloid Preload versus Crystalloid Co-Load in the Setting of Norepinephrine Infusion during Cesarean Section: Time and Type of Administered Fluids Do Not Matter. J. Clin. Med. 2023, 12, 1333"

We would like to take this opportunity to thank Drs Akça and Bilotta for their interest and their insightful comments [...].

Systematic review of viscoelastic testing (TEG/ROTEM) in obstetrics and recommendations from the women's SSC of the ISTH

Thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are point-of-care viscoelastic devices that use whole blood samples to assess coagulation and fibrinolysis. These devices have been studied extensively in cardiac surgery, but there is limited robust evidence supporting its use in obstetrics. The hesitancy toward its routine use in obstetrics may be due to the current lack of randomized controlled trials and large observational studies. The study aims to systematically review studies that investigated TEG/ROTEM use in pregnancy or peripartum, and to provide recommendations for future studies to fill current research gaps. We performed a systematic review of studies on viscoelastic testing in obstetrics. Included studies were original research, used TEG or ROTEM during pregnancy or peripartum, and published in English. Ninety-three studies, spanning 31 years from 1989 to 2020 and with a total of 32,817 participants, were included. Sixty-two (66.7%) of the studies used TEG and 31 (33.3%) used ROTEM. To date, there are a total of two randomized controlled trials on TEG/ROTEM use in obstetrics. ROTEM may be used to guide transfusion therapy for postpartum hemorrhage. TEG and ROTEM can detect the hypercoagulable changes associated with pregnancy. Variability between study protocols and results suggests the need for future large prospective high-quality studies with standardized protocols to investigate the utility of TEG/ROTEM in assessing risk for thrombosis and hemorrhage as well as in guiding prophylaxis and treatment in obstetric patients. This review identifies the gaps and provides concrete recommendations for future studies to fill those gaps.

Techniques for preventing hypotension during spinal anaesthesia for caesarean section

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury).

OBJECTIVES

To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included 125 studies involving 9469 women. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids) Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloid Fewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.69, 95% CI 0.58 to 0.81; 2009 women; 27 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women; very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.98, 95% CI 0.54 to 1.78, 5 studies, 413 women; very low-quality evidence), nausea and/or vomiting (average RR 0.89, 95% CI 0.66 to 1.19, 14 studies, 1058 women, I² = 29%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 10 studies, 730 babies; very low-quality evidence). Ephedrine versus phenylephrine There were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus control Ondansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus control Lower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42, 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lying There was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence). Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections. External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration.

AUTHORS' CONCLUSIONS

While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.

Evaluation of Renal Function with Administration of 6% Hydroxyethyl Starch and 4% Gelatin in Major Abdominal Surgeries: A Pilot Study

Background:

Synthetic colloids, both starches and gelatins, are commonly used as intravascular fluid replacements on account of increased vascular persistence. The safety on renal outcomes during perioperative use is poorly understood.

Aims:

We evaluated renal outcomes of hydroxyethyl starch 6% (HES) and gelatins 4% (G) in patients undergoing elective abdominal surgery. The primary outcome was serum creatinine measurements at baseline, 12 h, 36 h, and 1 week postoperatively (T₀, T₁₂, T₃₆, and D₇). The secondary outcomes were measurements of prothrombin time (PT), international normalized ratio (INR), fibrinogen, and activated partial thromboplastin time (aPTT) at baseline, 12 h, and 36 h postoperatively.

Setting and Design:

A prospective randomized study was conducted at a tertiary care institute.

Materials and Methods:

Seven-five adult patients received either HES (Group H) or gelatin (Group G) at 20-ml/kg body weight or only crystalloids (Group C) during surgery. Statistical tests used were one-way ANOVA, Student's t-test, Pearson correlation method, and Chi-square test.

Results:

Serum creatinine assessed at T₀, T₁₂, T₃₆, and D₇ was comparable between the three groups. PT/INR and aPTT showed no significant increase in values of T₁₂ and T₃₆ in comparison to T₀. Fibrinogen level was significantly higher in Group C at T₁₂ and T₃₆. Intraoperative vasopressor use, need for product transfusion, length of intensive care unit stay, and return of bowel function were similar between the three groups.

Conclusions:

Intraoperative use of HES (130/0.4) or gelatin (4%) at 20-ml/kg body weight was not associated with renal dysfunction or altered PT and aPTT in adult patients undergoing elective abdominal major surgeries.

Techniques for preventing hypotension during spinal anaesthesia for caesarean section

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury).

OBJECTIVES

To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE.

MAIN RESULTS

We included 126 studies involving 9565 participants. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids)Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloidFewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.68, 95% CI 0.58 to 0.80; 2105 women; 28 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women;very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.99, 95% CI 0.55 to 1.79, 6 studies, 509 women; very low-quality evidence), nausea and/or vomiting (average RR 0.83, 95% CI 0.61 to 1.13, 15 studies, 1154 women, I² = 37%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 11 studies, 826 babies; very low-quality evidence). Ephedrine versus phenylephrineThere were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus controlOndansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus controlLower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42 , 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lyingThere was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence).Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections.External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration.

AUTHORS' CONCLUSIONS

While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.

Effects of hydroxyethyl starch 6 % (130/0.4) on blood loss during cesarean delivery: a propensity-matched analysis

BACKGROUND

Hydroxyethyl starch is commonly used in the obstetric patient population to prevent hypotension during cesarean delivery. Evidence suggests hetastarch is associated with a dysfunction in coagulation cascade. We hypothesized that hetastarch use to prevent spinal hypotension during cesarean delivery would be associated with an increase in blood loss when compared to crystalloid use.

METHODS

We performed a retrospective review of patients who underwent elective cesarean delivery under spinal anesthesia at the University of Virginia between 2011 and 2014. Data from 819 patients was used. Blood loss was the primary outcome. Propensity score-matching was used to match patients who received hetastarch (treatment group) with those who did not receive hetastarch (control group).

RESULTS

Genetic matching resulted in 196 patients in the hetastarch group and 182 patients in the control group. There was no difference in estimated blood loss (p = 0.068), calculated blood loss (p = 0.720), total intraoperative fluid intake (p = 0.289), urine output (p = 0.421), Apgar 1 min (p = 0.830), Apgar 5 min (p = 0.138), phenylephrine consumption (p = 0.742), postoperative day 1 (POD1) hematocrit (p = 0.070) and POD1 platelets (p = 0.233). However, there was a statistically significant difference (but clinically irrelevant) in hematocrit difference between the day of admission and POD1 (mean difference 0.47, p = 0.024), and ephedrine consumption (mean difference 2 mg, p = 0.017) in favor of the control group.

CONCLUSIONS

Our study did not find an association between increased perioperative blood loss and hetastarch use in patients presenting for elective cesarean delivery.

Fluids and coagulation

PURPOSE OF REVIEW

Infusion therapy is essential in intravascular hypovolaemia and extravascular fluid deficits. Crystalloidal fluids and colloidal volume replacement affect blood coagulation when infused intravenously. The question remains if this side-effect of infusion therapy is clinically relevant in patients with and without bleeding manifestations, and if fluid-induced coagulopathy is a risk factor for anaemia, blood transfusion, and mortality, and a driver for resource use and costs.

RECENT FINDINGS

Pathomechanisms of dilutional coagulopathy and evidence for its clinical relevance in perioperative and critically ill patients are reviewed. Furthermore, the article discusses medicolegal aspects.

SUMMARY

The dose-dependent risk of dilutional coagulopathy differs between colloids (dextran > hetastarch > pentastarch > tetrastarch, gelatins > albumin). Risk awareness includes monitoring for early signs of side-effects. With rotational thromboelastometry/thrombelastography, the deterioration not only in clot strength but also in clot formation and in platelet interaction can be assessed. Fibrinogen concentrate administration may be considered in severe bleeding as well as relevant dilutional coagulopathy. Targeted doses of gelatins and tetrastarches seem to have no proven adverse effect on anaemia and allogeneic blood transfusions. Further studies are needed.

The Evaluation of Hydroxyethyl Starch (6% HES 130/0.4) Solution's Potential Preventive Effects on Coagulation Status in Women with Gynecologic Malignancies Using Rotation Thromboelastography

Objective: The aim of this study was to determine the effects of in vitro hemodilution with 6% hydroxyethyl starch (HES) 130/0.4 solution on the coagulation status of women with gynecologic malignancies by using rotation thromboelastogram (ROTEM®).

Materials and Methods: Twenty-two patients with gynecological tumors scheduled for anesthesia were enrolled. Blood samples were diluted by 20% with 6% HES (130/0.4) solution.

Results: In the INTEM assay, clotting time (CT) (p<0.01) and clot formation time (CFT) (p<0.001) were significantly increased and maximum maximum clot formation (MCF) (p< 0.001) was significantly decreased in HES hemodilution compared with the undiluted control samples. In the EXTEM assay, there was a similar significant increase in increase in CFT (p<0.01) and a decrease in maximum a decrease in MCF (p<0.01) in HES hemodilution when compared with control samples.

Conclusion: HES 130/0.4 solution causes significant hypocoagulable changes in the thromboelastographic profile of gynecologic cancer patients in vitro.

6% Hydroxyethyl starch (130/0.4) vs Ringer's lactate preloading before spinal anaesthesia for Caesarean delivery: the randomized, double-blind, multicentre CAESAR trial

BACKGROUND

Vasopressor administration is recommended to prevent hypotension during spinal anaesthesia (SA) for elective Caesarean delivery. We aimed to test the superior efficacy and ensure safety of a hydroxyethyl starch (HES) vs a Ringer's lactate (RL) preloading, when combined with a phenylephrine-based prophylaxis.

METHODS

A total of 167 healthy parturients undergoing elective Caesarean delivery under SA were included in this multicentre, randomized, double-blind study. Patients received 500 ml of 6% HES (130/0.4)+500 ml of RL (HES group) or 1000 ml of RL (RL group) i.v. before SA. After SA, i.v. phenylephrine boluses were titrated when systolic arterial pressure (SAP) was below 95% of baseline. The primary outcome was the incidence of maternal hypotension (SAP <80% of baseline).

RESULTS

The incidence of both hypotension and symptomatic hypotension (i.e. with dizziness, nausea/vomiting, or both) was significantly lower in the HES group vs the RL group: 36.6% vs 55.3% (one-sided P=0.025) and 3.7% vs 14.1%. There was no significant difference in total phenylephrine requirements [median (range): 350 (50-1800) vs 350 (50-1250) µg]. The decrease in maternal haemoglobin value the day after surgery was similar in the two groups [1.2 (1.0) vs 1.0 (0.9) g dl(-1)]. There was no detectable placental transfer of HES in six umbilical cord blood samples analysed in the HES group. Neonatal outcomes were comparable between the groups.

CONCLUSIONS

Compared with a pure RL preloading, a mixed HES-RL preloading significantly improved prevention of both hypotension and symptomatic hypotension based on early phenylephrine bolus administration and did not induce adverse effects.

CLINICAL TRIAL REGISTRATION

NCT00694343 (http://clinicaltrials.gov).