Comparison of crystalloid and colloid co-load combined with norepinephrine prophylaxis on post-spinal anesthesia hypotension during cesarean delivery: a randomized sequential allocation dose-finding study

Background

Fluid loading is an essential component of treatment for reducing the incidence of post-spinal anesthesia hypotension and is necessary to maintain intravascular volume, perfuse tissues, and control spinal anesthesia hypotension after sympathetic blockade. We performed a randomized sequential allocation dose-finding study to compare the effects of 10 mL/kg crystalloid and 6% hydroxyethyl starch (130/0.4) co-load on the ED90 of prophylactic norepinephrine infusion for preventing post-spinal anesthesia hypotension during cesarean delivery.

Methods

Eighty patients were randomly allocated to receive either a 10 mL/kg crystalloid (Crystalloid Group, n = 40) or 6% hydroxyethyl starch (130/0.4) (Colloid Group, n = 40) co-load combined with prophylactic norepinephrine infusion during spinal anesthesia for cesarean delivery. The first patient received an initial prophylactic norepinephrine infusion rate of 0.025 μg/kg/min. Subsequent patients received a 0.005 μg/kg/min gradient dose of prophylactic norepinephrine. This dose was administered as a gradient based on its effectiveness for preventing post-spinal anesthesia hypotension (defined as SBP < 80% of baseline value) and determined by the up-and-down sequential allocation methodology. The primary study outcome was the ED90 of prophylactic norepinephrine infusion. Secondary outcomes included the incidence of post-spinal anesthesia hypotension, bradycardia, hypertension, Apgar scores, and umbilical artery blood gas values were also measured.

Results

The ED90 values of prophylactic norepinephrine infusion for preventing post-spinal anesthesia hypotension during cesarean delivery were 0.063 μg (95% CI: 0.050 to 0.064) and 0.062 μg (95% CI: 0.045 to 0.064) using isotonic regression analysis, and 0.068 μg (95% CI: 0.056 to 0.353) and 0.060 μg (95% CI: 0.050 to 3.590) using probit regression analysis in the Crystalloid Group and Colloid Group, respectively. The secondary outcomes were comparable between the two groups.

Conclusion

The administration of a 10 mL/kg 6% hydroxyethyl starch (130/0.4) does not provide additional benefits compared to crystalloid co-load in reducing the ED90 of prophylactic norepinephrine infusion for preventing post-spinal anesthesia hypotension during cesarean delivery.

Colloid preloading versus crystalloid preloading to prevent hypotension after spinal anesthesia for cesarean delivery: A protocol for systematic review and meta-analysis

BACKGROUND

Maternal hypotension is the most frequent complication of spinal anesthesia for cesarean delivery, and intravenous fluid preloading is a preventive measure. We aimed to assess the efficacy of colloids versus crystalloids for preloading to reduce the incidence of spinal anesthesia-induced hypotension and vasopressor requirement in healthy parturients during elective cesarean delivery.

METHODS

We searched the Cochrane Library, MEDLINE and EMBASE to identify all studies published to June, 2019, through OVID and PubMed. We included randomized controlled trials, comparing colloid preloading with crystalloid preloading in women having spinal anesthesia for cesarean delivery. Primary outcomes were the incidence of hypotension and vasopressor requirement. Secondary outcomes included nausea and/or vomiting, neonatal Apgar score, neonatal umbilical blood pH. We used standardized mean differences for expressing continuous outcomes and risk ratios for dichotomous outcomes. Random-effect model was performed to estimate the pooled risk ratios and standardized mean differences.

RESULTS

Thirty-three randomized controlled trials contributed data for this meta-analysis. Fewer women experienced hypotension in the colloid group compared with the crystalloid group (risk ratio: 0.72, 95% confidence interval: 0.63-0.82; 2566 women, 32 studies; P < .00001). The total ephedrine dose required was significantly lower with colloid preloading (standardized mean difference: -0.37, 95% CI: -0.64 to -0.09; 1472 women, 19 studies; P = .009). Colloid preloading was also associated with fewer phenylephrine requirement compared with crystalloid preloading (standardized mean difference: -0.54, 95% CI: -0.82 to -0.25; 169 women; P = .0002). The incidence of nausea and/or vomiting was significantly reduced with colloid preloading (risk ratio: 0.72, 95% CI: 0.55-0.95; 1601 women, 20 studies; P = .02). However, the incidence of 1-minute Apgar score < 7, umbilical artery pH < 7.2 and umbilical vein pH < 7.2 were not statistically different between groups.

CONCLUSIONS

Colloid preloading is superior to crystalloid preloading in reducing the incidence of hypotension induced by spinal anesthesia and vasopressor requirement in the healthy parturients undergoing elective cesarean delivery.The PROSPERO registration number: CRD42018096402.

Effectiveness of Granisetron in Prevention of Hypotension Following Spinal Anaesthesia in Patients Undergoing Elective Caesarean Section

Background and aim: Spinal anesthesia is the most common type of anesthesia administered for caesarean section and it is frequently associated with hypotension. When post-spinal hypotension is accompanied with bradycardia, the condition may become more complicated. Numerous pharmacological agents have therefore been tried for prevention of hypotension and 5HT3 antagonists are the latest in the armamentarium. However, studies have shown conflicting evidence regardings the effectiveness of 5HT3 inhibitors (ondansetron and granisetron) in preventing spinal hypotension. We have tried to address this controversy and also wanted to explore the adverse effects of granisetron on the foetus, if any.

Materials and methods: Two hundred patients were included in the study and divided into two groups of 100 patients each. Group S patients received 5ml of 0.9% normal saline while Group G patients received IV granisetron 1mg (diluted to 5ml) 10 minutes prior to administration of spinal anesthesia. Analysis of variance (ANOVA) test was used for comparing the data, Student t-test was applied to compare the difference between the two means and Chi-Square test was used to test significance of difference of proportions.

Results: The incidence of hypotension in Group S was 69%, whereas it was 37% in Group G (p<0.001), hence patients of Group S required a significantly higher (p=0.001) amount of mephentermine. Haemodynamic parameters were well maintained throughout the study period in patients of Group G. The neonatal outcome was assessed by Apgar score at 0 minutes, one minute, and five minutes after delivery, and it was comparable between the two study groups.

Conclusion: Intravenous granisetron 1mg if administered before administering spinal anesthesia can effectively attenuate hypotension in parturients without any adverse effects on the mother and the neonate.

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.

Time from neuraxial anesthesia placement to delivery is inversely proportional to umbilical arterial cord pH at scheduled cesarean delivery

BACKGROUND

Neuraxial block-related hypotension and maternal obesity contribute to uterine hypoperfusion and decreased umbilical arterial pH at cesarean delivery. Between the time of anesthesia placement and delivery, the fetus may be exposed to a hypoperfused uterine environment without surgeon awareness of fetal compromise.

OBJECTIVE

We sought to evaluate neonatal umbilical arterial pH according to predelivery time intervals at scheduled term cesarean.

STUDY DESIGN

We performed a retrospective cohort study of cesarean deliveries between September 2014 and February 2017. Singleton gestations undergoing scheduled cesarean delivery under spinal anesthesia between 37 and 41 weeks with a reassuring preoperative nonstress test were included. Time intervals between operative room entry, spinal anesthesia placement, skin incision, uterine incision, and delivery were calculated. The primary outcome was umbilical arterial pH. Demographic data, maternal blood pressures, predelivery time intervals, and delivery outcomes were analyzed according to umbilical arterial pH intervals of <7.0, 7.01-7.10, 7.11-7.20, 7.21-7.30, and >7.30. Umbilical cord gas analytes and neonatal outcomes were analyzed by spinal to delivery time. Stepwise linear regression was performed to identify predictors of decreasing umbilical arterial pH. Receiver-operator characteristic curves were calculated for spinal to delivery time and umbilical arterial pH <7.0 and 7.1.

RESULTS

Among 527 included participants, median umbilical arterial pH was 7.27 [interquartile range, 7.23-7.29] and body mass index was 35 kg/m² [interquartile range, 30-41]. Both maternal body mass index and hypotensive episodes increased with decreasing umbilical arterial pH (P <.001, P ≤ .02). All predelivery time intervals (operative room to delivery, spinal to skin, spinal to delivery, and uterine incision to delivery) increased as umbilical arterial pH interval decreased (P < .05 for all). In a stepwise linear regression, maternal body mass index, noncephalic presentation, spinal start to delivery interval, uterine incision to delivery interval, and maximum reduction in blood pressure from baseline were predictive of decreasing umbilical arterial pH after controlling for confounding variables (F [5,442] = 17.7, P = .0001], adjusted R² of 0.157. When evaluated by spinal to delivery time, both umbilical arterial and venous pH and partial pressure of carbon dioxide decreased (P < .001 for all), but base deficit and neonatal outcomes were similar (P ≥ .7 for all). There were 2 cases of hypoxic-ischemic encephalopathy (0.38%). A receiver-operating characteristic curve demonstrated that a spinal start to delivery time greater than 27 minutes was associated with an umbilical arterial pH <7.1 (area under the curve, 0.74, 100% sensitivity, 21% specificity), and an interval greater than 30 minutes was associated with an umbilical arterial pH <7.0 (area under the curve, 0.80, 100% sensitivity, 33% specificity).

CONCLUSION

Longer spinal-to-delivery and uterine incision-to-delivery time intervals were associated with decreasing umbilical arterial pH at scheduled term cesarean delivery. Efforts to minimize predelivery time following spinal placement could reduce the frequency of unanticipated neonatal acidemia.

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.

Comparison of colloid preload versus coload under low dose spinal anesthesia for cesarean delivery

Background:

Although fluid bolus is considered as a conventional prophylactic measure to prevent spinal-induced hypotension; vasopressors are nevertheless required. Low dose spinal anesthetics could markedly reduce such episodes of hypotension, by minimizing sympathetic blockade.

Aims:

We chose to compare the relative efficacy of colloid preload versus coload under low dose spinal anesthesia, for elective cesarean delivery.

Settings and Design:

A prospective, randomized, double-blinded study.

Materials and Methods:

In total, 42 parturients were randomized to receive a preload (Group P) of hydroxyl ethyl starch (10 ml/kg) over 20 min before initiation of low dose spinal anesthesia (hyperbaric bupivacaine 5.5 mg with fentanyl 25 μg) or coload (Group C) of an identical fluid over 5 min, starting at the time of identification of cerebrospinal fluid. Our primary outcome included hemodynamic parameters and the incidence of hypotension. The neonatal outcome and side-effects were also monitored.

Statistical Analysis:

Mann-Whitney U test and Fisher's exact/Chi-square test, whichever appropriate. A P < 0.05 was considered to be significant.

Results:

The incidence of hypotension was lower in Group P (10%) when compared with Group C (25%), though insignificant statistically. The hemodynamic parameters were better in Group P, though intergroup statistical differences were not observed. The time to the first episode of hypotension was longer in the Group P (17 min) as compared with Group C (14 min). No notable side-effects or adverse neonatal outcome was noted.

Conclusion:

Colloid preload has a clinical advantage over the coload strategy, in reducing hypotensive episodes under low dose spinal anesthesia. Preload is better under large hemodynamic fluctuations while coload is preferable for emergency scenarios.

Update on volume therapy in obstetrics

Symptomatic hypotension (maternal nausea, vomiting, dizziness and dyspnoea) during spinal anaesthesia for caesarean delivery remains a prevalent clinical problem. Severe and sustained hypotension can lead to impairment of uteroplacental perfusion, foetal hypoxia, acidosis, neonatal depression and further adverse maternal outcomes of unconsciousness, pulmonary aspiration, apnoea and cardiac arrest. Mechanical methods aimed at countering the effects of aortocaval compression do not reliably prevent maternal hypotension. Intravenous crystalloid preloading (given prior to administration of spinal anaesthesia) has poor efficacy, and focus has changed towards decreased use of crystalloid preload and ephedrine, to increased use of coload (given at the time of spinal administration) with colloids or crystalloids, and early use of phenylephrine. The recent multicentre, randomised, double-blinded CAESAR trial demonstrated the efficacy of a mixed 500 ml 6% hydroxyethyl starch (HES) 130/0.4 + 500 ml Ringer's lactate (RL) preload in significantly reducing hypotension, compared to a 1-l RL preload, without adverse effects on coagulation and neonatal outcomes in healthy parturients undergoing caesarean delivery under spinal anaesthesia.

Crystalloid and colloid preload for maintaining cardiac output in elderly patients undergoing total hip replacement under spinal anesthesia

The aim of the present study was to compare the effects of colloid and crystalloid preload on cardiac output (CO) and incidence of hypotension in elderly patients under spinal anesthesia (SA). A randomized, double-blinded study was conducted including 47 elderly patients undergoing scheduled total hip replacement (THR), who were randomized to three groups: the control group (C group, n = 15), crystalloid (RS group, n =16) and colloid group (HES group, n = 16). An intravenous preload of 8 mL/kg of either lactated Ringer's solution in the RS group or 6% hydroxyethyl starch in the HES group was infused within 20 min before SA induction, while no intravenous preload was given in the C group. There was a trend of decrease in CO and systolic blood pressure after SA with time in the C group. In the RS and HES groups, CO increased significantly after fluid preloading as compared with baseline (P < 0.01). Thereafter, CO remained higher than baseline until 30 min after SA in the HES group. The change of systolic blood pressure was similar to CO, but no significant difference from baseline was observed in each group. Hypotension occurred in 3 patients in the C group and one each in the RS and HES group, respectively (P = 0.362). Intravascular volume preload with colloid is more effective than crystalloid solution in maintaining CO, which may be improved the hemodynamic stability in elderly patients during SA.

Prevention of post-spinal hypotension using crystalloid, colloid and ephedrine with three different combinations: A double blind randomized study

Background:

The benefit of prophylactic combination therapy using crystalloid and colloid preload with ephedrine has not been cleared to prevent maternal hypotension after spinal anesthesia at cesarean delivery. This study evaluated the efficacy of three combinational methods to prevent hypotension following spinal anesthesia.

Materials and Methods:

In this prospective double blind trial, 150 candidates of elective cesarean delivery under spinal anesthesia were randomly allocated to three treatment groups; 1---Ringer's Lactate (RL) solution (15 ml/kg) plus Hemaxel (7 ml/kg) preload, 2---RL solution (15 ml/kg) preload plus ephedrine (15 mg, IV, bolus), 3---Hemaxel (7 ml/kg) preload plus ephedrine (15 mg, IV, bolus). Maternal hemodynamic changes during 60 min after spinal injection, nausea/vomiting, and neonatal condition were compared among the groups.

Results:

The cumulative incidence of hypotension was 44%, 40%, and 46% in groups 1 to 3, respectively. There were not significant differences in supplementary ephedrine requirement among groups which received or among groups which did not receive prophylactic ephedrine. Groups were not different in the incidence of hypertension and nausea or vomiting. There were no significant differences among groups in Apgar scores at 1 or 5 min and umbilical artery PH.

Conclusion:

Combination of preventive methods decreased the occurrence of hypotension following spinal anesthesia to an acceptable level. Overall, the most effective method was a combination of crystalloid preload with ephedrine.

[Anesthesiological management of Caesarean sections : nationwide survey in Germany]

BACKGROUND

The rate of Caesarean sections in Germany continues to rise. The change in anesthetic technique of choice from general to spinal anesthesia began later than in other countries and at the last survey in 2002 was not widely established. The literature on the anesthetic management of Caesarean sections contains many controversies, for example fluid preload before performing spinal anesthesia and the vasopressor of choice. Other issues have received relatively little attention, such as the level of experience of anesthesiologists working autonomously on the labour ward or the timing of antibiotic prophylaxis. The aim of the current survey was to provide an updated overview of anesthetic management of Caesarean sections in Germany.

MATERIAL AND METHODS

A questionnaire was sent out to 709 departments of anesthesiology serving obstetric units in Germany. The questionnaire concerned various aspects of anesthetic management of Caesarean sections.

RESULTS

A total of 360 questionnaires (50.8%) were returned of which 346 were complete and could be analyzed, accounting for 330,000 births and 90,000 Caesarean sections per year. The predominant anesthetic method used for Caesarean sections was spinal anesthesia (90.8%) using hyperbaric bupivacaine and in approximately one third of the hospitals surveyed without administering intrathecal opioids. Approximately 12% of the departments surveyed used traumatic Quincke needles. In 86.2% the vasopressor of choice was caffedrine/theodrenaline. Nitrous oxide was used in only 19.2% of departments surveyed when general anesthesia is performed. An antibiotic drug was administered in only 11% of hospitals before cord clamping. In 43.1% no neonatologist was available to treat unexpected critically ill newborns. In 32.1% of departments surveyed residents with less than 2 years experience worked autonomously on the labour ward.

CONCLUSIONS

Currently the predominant anesthetic technique of choice in Germany is spinal anaesthesia and at a much higher rate than in 2002. In addition 12% of departments use traumatic Quincke needles which are associated with a higher incidence of postpuncture headache. Nitrous oxide is no longer frequently used in Germany. Finally, the administration of an antibiotic before cord clamping has been shown to lead to lower rates of endometritis and postoperative wound infection without detrimental effects on the newborn. This is practiced in only a small minority of departments across Germany.