Volume Preloading Research Articles

The Effect of Volume Preload versus Ephedrine Infusion for Prevention of Hypotension due to Spinal Anesthesia for Cesarean Section

Abstract Background Spinal anesthesia is the preferred method for elective cesarean sections due to considerable risks regarding airway management associated with physiological changes of pregnancy. We hypothesized that using ephedrine to maintain maternal blood pressure during spinal anesthesia for cesarean delivery provides better hemodynamic stability with subsequent better maternal and neonatal outcomes compared to volume preload. Aim of the Work We compared volume preload and ephedrine infusion to guard against the hypotensive effect of spinal anesthesia during cesarean delivery. Patients and Methods After obtaining approval from the Research Ethical Committee of Faculty of Medicine, Ain Shams University, and written informed consent this study was conducted in the operating theaters of Ain Shams University Hospitals. This study was a randomized Controlled Clinical Trial. Adult parturients undergoing cesarean section under spinal anesthesia randomly assigned into one of the following groups using computer generated codes and opaque sealed envelopes: Group (A) received Volume Preload, group (B) received Ephedrine Infusion. Results The results of the study showed that compared with volume preload, ephedrine maintained maternal blood pressure and uterine artery blood flow. Further, it was associated with lower numbers of hypotension and hypertension episodes and less frequency of bradycardia and tachycardia during cesarean delivery. Conclusion Furthermore, the numbers of boluses of vasopressors used during spinal anesthesia were lower in ephedrine compared with volume preload.

To Study Preloading and Relative Efficacy of Ringer’s Lactate and Pentastarch 6% Prior to Spinal Anaesthesia in Lower Abdominal and Lower Limb Surgeries

Background and Objectives: Hypotension after spinal anaesthesia remains a common and a seriouscomplication. Various method have been recommended for the prevention and treatment of this problem.Preloading has become the cornerstone for prophylaxis of hypotension post spinal anaesthesia. This currentstudy reassessed the efficacy of this volume preloading and also compared the efficacy between Ringer’slactate and Pentastarch 6%.Method: In this study, 60 patients (ASA I & II) presenting for elective lower abdominal and lower limbsurgeries under spinal anaesthesia were allocated into two groups, group P and group R to receive 5 ml/kg of6% Pentastarch and 10 ml/kg of Ringer’s lactate preload respectively. After institution of spinal anaesthesiain a sitting position with 3.8 ml of Bupivacaine 0.5% (heavy) using 23G Quincke spinal needle, patientswere made to assume supine position. The heart rate(HR), systolic blood pressure(SBP) and diastolic bloodpressure(DBP) were monitored intra-operatively every 2 minutes for first 10 minutes and every 5 minutesfor next one hour and every 15 minutes thereafter. Electrocardiogram (ECG) and oxygen saturation(SpO2)were monitored continuously. The amount of ephedrine, used intra-operatively were noted and comparedamong the different groups.Results: The incidence of hypotension in group R was more than that in group P. There were no significantdifference in HR and the SpO2 between the groups. The difference in mean basal SBP and DBP werestatistically insignificant in both groups. Thereafter, the fall in SBP and DBP was more prominent in groupR at all time intervals with a statistically highly significant difference between the two groups (p value<0.001). The amount of ephedrine used in group R was more than that used in group P. There were minimalcomplications like shivering and vomiting which were statistically non–significant . There were no allergicreactions to the fluids used.Conclusion: Volume preloading, still has a substantial role in reducing the incidence and severity ofhypotension in patients operated under spinal anaesthesia. Pentastarch 6% is found to be a better agent forpreloading, as it is safe and effective in preventing spinal-induced hypotension in patients.

Volume Preload versus Ephedrine Infusion for Prevention of Hypotension Due to Spinal Anesthesia for Cesarean Section

Introduction: Spinal anesthesia is used for 95% of planned cesarean sections in Bangladesh. It provides a fast and profound sensory and motor block. However, hypotension is a very common complication of spinal anesthesia during cesarean section, causing significant maternal and fetal morbidity and mortality. It could be associated with severe nausea, vomiting and even unconsciousness and pulmonary aspiration in the mother and for the baby hypoxia, acidosis and neurological injuries may result.
 Materials and Methods: This prospective randomized comparative study was conducted in the Department of Anesthesiology at Institute of Child and Mother Health (ICMH) from July 2017 to December 2017, on 110 adult pregnant women who underwent caesarean delivery. All study patients were randomly allocated into two groups. Group I (F group) patients received volume preloading with 15 ml/kg Ringer lactate solution before induction of spinal anesthesia and group II (E group) patients received IV ephedrine (5 mg in 1st minute after spinal anesthesia, 5 mg in 2nd minute and thereafter 1 mg in every minute for 15 minutes).
 Results: A statistically significant difference in the incidence of hypotension between group F (48%) and group E (24%) was found (p = 0.03). Regarding side effects, statistically significant (p = 0.23) incidence of nausea and vomiting was found in group F (20%) in comparison to group E (12%).
 Conclusion: We conclude that prophylactic IV ephedrine infusion is more effective than fluid preload to prevent spinal anesthesia-induced hypotension during caesarean section without causing significant tachycardia or hypertension.
 Medicine Today 2019 Vol.31(1): 39-41

Level of sensory block after spinal anesthesia as a predictor of hypotension in parturient.

When the sensory block level (SBL) is ≥T5 or T4, a high incidence of hypotension occurs in parturients after spinal anesthesia. A rapidly ascending SBL is another risk factor for spinal anesthesia-induced hypotension. However, the relationship between the ascension rate of the SBL and spinal anesthesia-induced hypotension remains unclear.After placement in the left lateral position, combined epidural–spinal anesthesia was performed on 140 parturients undergoing caesarean section using the following procedure: no volume preloading, injection site of L3–4 or L4–5, injection rate of 0.1 mL/sec, and administration of 10 mg of 0.5% hyperbaric bupivacaine. A receiver-operating characteristic curve was built to estimate the accuracy of the SBL ascension rate in detecting spinal anesthesia-induced hypotension.The mean time interval from spinal injection to placement in the supine position was 136 ± 10 seconds in all anesthesia procedures. The earliest and most complete records of the SBL started from the 3rd minute after spinal injection. The threshold spread rate corresponding to the highest accuracy for occurrence of hypotension was an SBL of ≥T8 at the 3rd minute after spinal injection, with 82% and 88% sensitivity and specificity, respectively.The ascension rate of an SBL of ≥T8 at the 3rd minute after spinal injection is as a predictor of hypotension in parturients.

Volume Preload versus Ephedrine Infusion for Prevention of Hypotension Due to Spinal Anesthesia for Cesarean Section

Background: Spinal anesthesia is used for 95% of planned cesarean sections in the United States. It provides a fast and profound sensory and motor block. However, hypotension is a very common complication of spinal anesthesia during cesarean section, causing significant morbidity and mortality. It could be associated with severe nausea, vomiting and even unconsciousness and pulmonary aspiration in the mother and for the baby, hypoxia, acidosis, and neurological injuries may result. Methodology: Fifty patients were randomly allocated into two groups. Group I (F group) patients received preloading with 15 ml/kg Ringer lactate before induction of spinal anesthesia, and group II (E group) patients received IV ephedrine (5 mg in 1st minute after spinal anesthesia and 5 mg in the 2nd minute and 1 mg every minute after that for 15 minutes). Results: A statistically significant difference in the incidence of hypotension between group F (48%) and group E (24%) was seen, (p-value 0.03). Regarding side effects, the incidence of nausea and vomiting was higher in the group F (20%) when compared to group E (12%), (p-value 0.23). Conclusions: We concluded that IV infusion of ephedrine after induction of spinal anesthesia was more effective than crystalloid preloading in a prevention of hypotension in parturient undergoing cesarean section and did so without causing significant tachycardia.

English

BACKGROUND: The hypotension induced by spinal anesthesia in caesarean section patients can have deleterious effects on both mother and fetus. This can be prevented or minimized by various methods like trendelenburg position, left uterine displacement, prophylactic vasoconstrictor, volume preloading etc. Volume preloading is commonly practiced method. However, few recent studies have found lack of benefit by fluid preload. Hence this study. AIM: To assess efficacy of fluid preloading using RL in preventing spinal induced hypotension in caesarean section patients. METHODOLOGY: Two groups' control (C) group and study (S) group comprising of 30 parturients each, belonging to ASA I and ASA II coming for elective caesarean section under spinal anesthesia were selected. Parturients in control group received no fluid preload whereas those in study group were preloaded with 1L RL. After spinal anesthesia, patients' blood pressure and other vital parameters were monitored intraoperatively every 2 min for first 20 min and then every 5 min till the end of surgery. RESULTS AND CONCLUSION: Parturients who received RL preloading had lesser number of hypotensive episodes and lesser severe degree of hypotension than those without volume preload. Volume preloading has its own beneficial effects on incidence of spinal induced hypotension in parturients undergoing elective LSCS.

Hemodynamic Effects during Combined Spinal and Epidural Anesthesia: Role of Fluid Preloading and Prophylactic Vasoconstrictors

The most common complication encountered with combined spinal and epidural anaesthesia is hypotension. Several interventions can be planned for prevention of hypotension after combined spinal and epidural anaesthesia. We compare fluid preloading with prophylactic vasoconstrictors (Ephedrine) in reducing the hemodynamic side effects of combined spinal and epidural anaesthesia. The study was carried out randomly on 60 patients in age group of 20 –65 yrs. Patients classified under class 1-3 as per ASA classification. Patients were randomly allocated to the two groups. GROUP-1 patients had received crystalloid preloading (Ringer Lactate) 20 minute before procedure at a rate of 15ml /kg and GROUP-2 patients had received prophylactic ephedrine intravenously 5mg, 5mg at 1 and 2 minute and 1mg at every minute thereafter for 15 minutes after block. HR, BP were recorded immediately after placing patient in supine position and then at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120 minutes. Minute to minute monitoring was done to assess any haemo-dynamic changes and early institution of corrective therapy. In both Group 1 and Group 2 sustained fall in systolic blood pressure was observed from baseline. In Group 1 the fall in BP was more and the difference was also statistically significant. There were comparable sequential rise in mean pulse rate in both the groups, although this was statistically non-significant. In Group 1 nine patients showed hypotension out of which four (44.5%) were managed with fluid challenge alone and rest five patients needed ephedrine. There were three hypotensive patients in Group 2; two out of them (66%) were managed by i.v. fluid boluses alone. Study showed that vasoconstrictor (ephedrine) is a more effective method in reducing the incidence and severity of fall in systolic blood pressure as compared to volume preloading.

A Randomised Trial Comparing 5 mL/kg and 10 mL/kg of Pentastarch as a Volume Preload before Spinal Anaesthesia for Elective Caesarean Section

Obstetric Anesthesia Digest: September 2007 - Volume 27 - Issue 3 - p 160 doi: 10.1097/01.aoa.0000288299.14070.93

Effect of volume preloading to prevent hypotension associated with epidural block combined general anesthesia

目的 比较晶体液和胶体液预负荷预防胸段硬膜外阻滞复合全麻诱导期低血压效应.方法ASA Ⅰ～Ⅱ级择期行上腹部手术患者90例,随机分为三组,每组30例.A、B和C三组分别以1000 ml复方乳酸钠注射液、500ml和1000 ml聚明胶肽溶液在40 min进行容量预负荷,在预负荷过程中,经T8～9行硬膜外穿刺置管,用1.6%利多卡因和0.2%丁卡因混合液进行硬膜外阻滞,预负荷结束后开始全麻诱导.结果硬膜外阻滞、全麻诱导后及气管插管后,A和B组血压显著低于C组,A、B和C组低血压的发生率分别为70%、57%和23%,C组显著低于A、B两组.结论胶体液容量预负荷预防胸段硬膜外阻滞复合全麻后低血压的效应优于等量的晶体液。

Assessment of volume preload on uteroplacental blood flow during epidural anaesthesia for Caesarean section

Epidural and spinal anaesthesia are the preferred mode of anaesthesia for Caesarean section. Volume preloading is recommended to prevent maternal hypotension and a reduction in uteroplacental blood flow, although positive effects of volume preloading on maternal cardiac output and arterial pressure are debatable. Doppler measurements of the umbilical artery beyond deriving pulsatility indices are not routinely performed. After Institutional Review Board approval and written informed consent, 14 consecutiVe women with epidural anaesthesia for Caesarean section received either hydroxyethyl starch 500 mL or gelatine 500 mL. Haemodynamic variables monitored were maternal arterial pressure, maximal blood flow velocity and pulsatility indices of the uterine artery derived from Doppler measurements. Maternal arterial pressure and pulsatility indices in both groups did not change from baseline after intravenous colloid infusion. However, uterine blood flow increased significantly in both groups. The effectiveness of volume preloading may therefore be better described by changes in maximum uterine blood flow velocity than by pulsatility indices or maternal arterial pressure.

Prophylactic continuous intravenous ephedrine infusion for elective Caesarean section under spinal anaesthesia

EDITOR: Maternal hypotension is the most frequent complication of a spinal anaesthetic for Caesarean section. A range of stratagems is currently used to prevent or minimize hypotension, but there is no established ideal technique. Different approaches include prehydration with crystalloids or colloids, lower limb compression, and pharmacological prophylactic protocols using ephedrine, phenylephrine, angiotensin II or metaraminol [1-4]. Loughrey and colleagues described the prophylactic administration of intravenous (i.v.) boluses of ephedrine for elective Caesarean section under spinal anaesthesia [1]. They concluded that a prophylactic bolus of ephedrine 12 mg i.v. given at the time of the intrathecal block - associated, if necessary, with rescue boluses - leads to a lower incidence of hypotension during spinal anaesthesia compared with i.v. rescue boluses alone. We use compound sodium lactate solution (500 mL) given as a preload over 10 min before the intrathecal injection of hyperbaric bupivacaine. The bolus method is chosen over an i.v. infusion to provide a fast and reliable early prophylactic dose of vasopressor as the rapid sympathetic blockade develops. In the recent study of Kee and colleagues, the smallest prophylactic i.v. ephedrine dose was 30 mg. In that study, the parturient was preloaded with lactated Ringer's solution 20 mL kg−1 and the spinal block was performed using hyperbaric bupivacaine 10 mg and fentanyl 15 μg [5]. In another trial by Vercauteren and colleagues, a single i.v. dose of 5 mg limited the severity of hypotension in prehydrated subjects receiving hyperbaric bupivacaine 6.6 mg and sufentanil 3.3 μg [6]. Jackson and colleagues concluded that volume preloading was not essential to prevent spinal-induced hypotension in Caesarean section. They used a prophylactic infusion of ephedrine 60 mg in Hartmann's solution (500 mL) given according to maternal arterial pressure [7]. During 2001, our Medical Centre performed 181 Caesarean section deliveries of which 94% were under spinal anaesthesia. The usual policy we adopted consisted of prehydration with lactated Ringer's solution (300 mL) over 10 min. At the same time, hyperbaric bupivacaine 0.8-1 mL 1%, combined with fentanyl 25 μg, was given intrathecally plus a slow baseline infusion of ephedrine 25 mg in 500 mL lactated Ringer's solution i.v. The aim of the ephedrine infusion was to keep arterial pressure at a baseline level and never below 90 mmHg systolic. This infusion was continued until the extraction of the baby and then it was gradually stopped. We did not observe rebound hyper- or hypotension. The mean total dose of ephedrine used was 12.5 ± 2.3 mg (mean ± SD). Only five patients required rescue boluses of ephedrine 5 mg because of symptoms suggestive of hypotension, e.g. nausea and vomiting, without any recorded fall of arterial pressure. We agree that the prophylactic ephedrine dose is safe and efficacious in reducing the incidence of maternal hypotension, but we also believe that an infusion of the drug, according to the patient's requirements, is much safer than the bolus technique. In our patients, the preload was reduced to 300 mL - similar to Jackson and colleagues' study [7] in which the minimal preload was 200 mL - while the concentration of ephedrine in our protocol was 0.05 versus 0.12 mg mL−1. In conclusion, further randomized control trials would be useful to determine the optimal dose of ephedrine, the method of administration, the volume and the kind of preload. Y. Leykin F. Rubulotta Department of Anesthesia and Intensive Care; Santa Maria degli Angeli Hospital; Pordenone, Italy

Which Parameter Measures the Effectiveness of Volume Preload in Pregnant Patients?

Osaka University Medical SchoolSuita, Osaka, Japan.ueyama@hp-op.med.osaka-u.ac.jpIn Reply:—We thank Dr. Marcus for the interest in our work and the comments. In parturients with normal uteroplacental circulation, uterine blood flow is the major determinant of oxygen transport to the fetus. The increase in uterine blood flow after colloid preload suggested by Dr. Marcus is interesting. Our results suggested that colloid preloading resulted in marked increases in maternal cardiac output without significant change in blood pressure. Therefore, the increase in uterine blood flow may be associated with an increase in maternal cardiac output.Doppler ultrasonography is the most commonly used method to measure uterine blood flow in humans. The velocity of the blood flow is one of the representative parameters measured with Doppler ultrasonography. However, the reliability of the measurements is controversial because shape of the waveform is affected by many factors, such as maternal cardiac output, elasticity of the vessel wall, outflow impedance, and blood viscosity. Calculation of blood flow necessitates precise determination of mean velocity, angle of insonation, and vessel diameter. Although angle of the insonation and blood velocity are determined correctly, accurate measurement of small-vessel diameters, such as the diameter of a uterine artery, is difficult. It is also not clear whether the blood flow reflects the functional placental perfusion because some portion of blood flow is shunted to the myometrium. Therefore, extrapolation of measurements from the Doppler ultrasonographic method must be done with caution.As Dr. Marcus pointed out, an understanding of the uteroplacental blood flow is essential in obstetric anesthesia practice. However, the goal of our anesthetic management is to maintain fetal oxygenation, not uterine artery blood flow. We think that, in the future, fetal oxygenation monitoring would show the effect of preloading on fetal oxygenation.

Comparison of Pentastarch and Hartmannʼs Solution for Volume Preloading in Spinal Anaesthesia for Elective Caesarean Section

Department of Anaesthetics, Northampton District General Hospital, Cliflonville, Northampton, UK, and Department of Anaesthetics, John Radcliffe Hospital, Headington, Oxford, UK

▪ Comparison of Pentastarch and Hartmannʼs Solution for Volume Preloading in Spinal Anaesthesia for Elective Caesarean Section

▪ Comparison of Pentastarch and Hartmannʼs Solution for Volume Preloading in Spinal Anaesthesia for Elective Caesarean Section

Continuous infusion of dopamine to maintain stable arterial pressure during spinal anaesthesia for caesarean section

To maintain stable maternal arterial blood pressure during spinal anaesthesia for caesarean section is a major concern for anaesthesiologists. Volume preloading, uterine displacement to the left and preventive administration of vasopressors are manoeuvres used by anaesthesiologists to prevent hypotension. In this study, the effects of continuous infusion of dopamine on maternal haemodynamic responses have been studied. Healthy women undergoing elective ceasarean section under spinal anaesthesia at term were allocated randomly to receive a continuous infusion of dopamine (5 μg kg−1 min−1: n=15, D-group) or non-dopamine infusion (n=15, non-D-group). After preloading with 1000 mL Ringer lactate solution, maternal arterial blood pressure (ABP), heart rate (HR) and pulse oxymetry were recorded. Spinal anaesthesia with 0.3% dibucaine (1.6–2.0 mL) at L2–3 or L3–4 was performed. The indication for bolus ephedrine was a reduction in ABP to ≤90% of base-line values. During spinal anaesthesia no significant difference in fluctuation of ABP and HR was detected between the D-group and the E-group. Only in the non-D-group, 10 of 15 patients, was the fall in ABP to a level for which bolus ephedrine was indicated. All neonates had 1-min Apgar scores of 8 or more. There were no significant differences in Apgar scores between the two groups. Continuous infusion of dopamine is effective for the prevention and management of maternal hypotension during spinal anaesthesia for caesarean section.

Volume Preloading Is Not Essential to Prevent Spinal-Induced Hypotension at Caesarean Section

Comment In medicine “sacred dogmas” should be periodically reexamined. Such is the case of the “requirement” of preloading with large volumes of intravenous balanced salt solutions (BSS) preceding a high subarachnoid block (SAB) or epidural block (EB) for cesarean sections. So ingrained has this con-

Volume preloading is not essential to prevent spinal-induced hypotension at caesarean section

We have compared the protective effect of 1000 ml preload with 200 ml preload of crystalloid solution, administered during the 10 min before spinal anaesthesia was induced, in 60 healthy women with no fetal compromise undergoing elective Caesarean section. The spinal anaesthetic was managed identically in both groups by an anaesthetist who was unaware of the volume of fluid administered. A prophylactic infusion of ephedrine 60 mg in Hartmann's solution 500 ml was given according to maternal arterial pressure. Hypotension was defined as > or = 30% reduction from baseline or < 90 mm Hg, and was treated by i.v. ephedrine bolus doses. There was no significant difference in ephedrine requirements between the two groups or in the incidence, severity or duration of hypotension: 10 women in the 1000-ml group, five episodes lasting > or = 3 min compared with nine women in the 200-ml group, four lasting > or = 3 min. There was no difference between neonates in each group. We have now abandoned the routine of preloading before regional anaesthesia.

Volume preloading is not essential to prevent spinal induced hypotension at caesarean section

Volume preloading is not essential to prevent spinal induced hypotension at caesarean section

A reevaluation of the role of crystalloid preload in the prevention of hypotension associated with spinal anesthesia for elective cesarean section.

Hypotension after spinal anesthesia for cesarean section remains a common and serious complication despite the use of uterine displacement and volume preloading. The current study revaluated the role of crystalloid volume preloading in this context. In a two-stage open sequential design, patients presenting for elective repeat cesarean section were allocated to receive either no preload or 20 ml/kg crystalloid administered over 15-20 min before spinal anesthesia. Hypotension was defined as a decrease in systolic pressure to less than 100 mmHg and to less than 80% of baseline value, and the study was designed to detect a 20% difference in the incidence of hypotension between the groups, with statistical significance at the 10% (alpha = 0.1) level, one-tailed. One hundred forty patients were studied. Hypotension occurred in 43 (55%, 95% CI 43.4-66.4) preloaded and 44 (71%, 95% CI 58-81.8) unpreloaded subjects, a difference in incidence of 16% (95% CI 0.04-31.6), which was statistically significant. There were no significant differences in the severity, timing, or duration of hypotension; the dose requirement for ephedrine; or the clinical and biochemical status of neonates between the groups. The only difference seen was a lower mean base excess (-3.4, SD 2.81 mM-1) in the neonates of hypotensive mothers compared to neonates of nonhypotensive mothers (-2.4, SD 1.99 mM-1). The study confirms that hypotension associated with spinal anesthesia for cesarean section cannot be eliminated by volume preloading in the supine wedged patient. The relatively small reduction in incidence of hypotension challenges our perception of the value of crystalloid preload. Though volume preload in the elective cesarean section is advocated, the requirement for a mandatory administration of a fixed volume before spinal anesthesia for urgent cases has been abandoned.

Anaesthetic management for surgical correction of coarctation of aorta

In this paper we have reviewed the anaesthetic management of 57 consecutive patients who underwent surgical correction of coarctation of aorta. The patients were divided into two groups. In group I of ten patients, no volume preloading was done prior to the release of aortic cross-clamp and the declamping hypotension was managed by rapid infusion of fluids along with correction of metabolic acidosis. In group II of 47 patients, volume preloading was done along with administration of sodium bicarbonate 1 mEq/kg just prior to declamping. Statistically significant (p<0.05) decrease in the systolic and diastolic pressures were observed after declamping in group I; whereas in group II, the hypotension observed was statistically insignificant. Declamping hypotension can thus be prevented or minimised by appropriate volume preloading and correction of existing metabolic acidosis just prior to the release of aortic cross-clamp.