Bolus Of Norepinephrine Research Articles

Intravenous initial bolus during prophylactic norepinephrine infusion to prevent spinal hypotension for cesarean delivery: A randomized controlled, dose-finding trial

BackgroundPrevious studies have shown that a 0.05 μg/kg/min of norepinephrine infusion in combination with an initial bolus reduces the incidence of spinal hypotension during cesarean delivery. The initial norepinephrine bolus influences the incidence of spinal hypotension during continuous norepinephrine infusion; however, the ideal initial bolus dose for 0.05 μg/kg/min of continuous infusion remains unknown. MethodsThis randomized, controlled, dose-finding study randomly allocated 120 parturients scheduled for elective cesarean delivery to receive initial bolus doses of 0, 0.05, 0.10, and 0.15 μg/kg of norepinephrine, followed by continuous infusion at a rate of 0.05 μg/kg/min. The primary outcome was the dose-response relationship of the initial norepinephrine bolus in preventing the incidence of spinal hypotension. Spinal hypotension was defined as systolic blood pressure (SBP) decreased to <80% of the baseline value or to an absolute value of <90 mmHg from intrathecal injection to delivery, and severe spinal hypotension was defined as SBP decreased to <60% of the baseline value. The secondary outcomes included the incidence of nausea and/or vomiting, hypertension, and bradycardia, as well as the Apgar scores and results of the umbilical arterial blood gas analysis. The effective dose (ED) 90 and ED95 were estimated using probit regression. ResultsThe per-protocol analysis included 117 patients. The incidence of spinal hypotension varied significantly among the groups: Group 0 (51.7%), Group 0.05 (44.8%), Group 0.10 (23.3%), and Group 0.15 (6.9%). The ED90 and ED95 values were 0.150 μg/kg (95% confidence interval [CI], 0.114–0.241 μg/kg) and 0.187 μg/kg (95% CI, 0.141–0.313 μg/kg), respectively. However, the ED95 value fell outside the dose range examined in this study. The incidence of severe spinal hypotension differed significantly (P = 0.02) among Groups 0 (17.2%), 0.05 (10.3%), 0.10 (3.3%), and 0.15 (0.0%); however, the incidence of hypertension and bradycardia did not. The incidence of nausea and/or vomiting decreased with an increase in the initial bolus dose (P = 0.03). The fetal outcomes were comparable among the groups. ConclusionsAn initial bolus of 0.150 μg/kg of norepinephrine may be the optimal dose for preventing spinal hypotension during cesarean delivery with a continuous infusion rate of 0.05 μg/kg/min, and does not significantly increase the incidence of hypertension but substantially reduces the risk of nausea and/or vomiting.

Comparative Efficacy of Intermittent Bolus Doses of Phenylephrine and Norepinephrine in Preventing Maternal Bradycardia during Cesarean Section under Spinal Anesthesia: A Randomized Controlled Trial

Background and Aims: Maternal hypotension is a common concern during cesarean sections (CS) with spinal anesthesia and can have adverse consequences for both the mother and fetus. This study aimed to investigate the prophylactic effectiveness of intermittent boluses of phenylephrine and norepinephrine in preventing maternal bradycardia during maintenance of systolic blood pressure (SBP) within 90–100% of baseline. Material and Methods: Two hundred American Society of Anesthesiologists physical status -II parturients scheduled for CS with subarachnoid block (SAB) were randomly assigned to Group A (phenylephrine, 50 µg) or Group B (norepinephrine, 4 µg). The primary goal was to assess the incidence of maternal bradycardia (≤50 bpm) whilst SBP maintenance at 90-100% of baseline. The secondary objectives encompassed total boluses administered, episodes of hypertension (≥120% of baseline), Intraoperative nausea and vomiting (IONV), and neonatal APGAR scores. The time from intrathecal injection to fetal delivery (induction–delivery interval) was also evaluated. Results: Both norepinephrine and phenylephrine groups effectively prevented spinal-induced hypotension, with similar outcomes However, Group A (phenylephrine) experienced a significantly higher incidence of bradycardia (18%) compared to Group B (norepinephrine) with only 5% (P=0.016). Episodes of hypertension, IONV, and neonatal APGAR scores were comparable between the two groups. Conclusion: Intermittent boluses of norepinephrine and phenylephrine demonstrated equivalent efficacy in preventing spinal-induced hypotension during CS. However, norepinephrine exhibited an advantage over phenylephrine by significantly reducing the incidence of bradycardia. These findings support the consideration of norepinephrine as an effective alternative vasopressor for maintaining maternal hemodynamics during CS under SAB.

Internal Jugular Vein Collapsibility Index versus Inferior Vena Cava Collapsibility Index Guided Preloading for Prevention of Spinal Anesthesia Induced Hypotension During LSCS: An Interventional Study

Background and Aims: Goal directed fluid therapy (GDFT) in parturients helps to prevent spinal anesthesia induced hypotension (SAIH) and volume overload. This interventional study compared the inferior vena cava collapsibility index (IVCCI) and the internal jugular vein collapsibility index (IJVCI) guided preloading for prevention of SAIH during lower segment ceserean section (LSCS) in terms of the incidence of SAIH as the primary outcome and the total amount of fluid, mean dose of the vasopressor, the number of boluses of vasopressor required, and the incidence of intra-operative complications as secondary outcomes. Methodology: A total of 144 full-term parturients aged 20–40 years with American society of anaesthesiologists (ASA) grade II, height (140–165 cms), weight (40–70 kgs), those who were fluid responders, and those who had a window period of 1 hour before surgery under spinal anesthesia (SA) undergoing LSCS were allocated into two groups (n = 72): group IJV and group IVC. Ultrasonography (USG) guided Internal jugular vein (IJV) and Inferior vena cava (IVC) collapsibility index (CI) was recorded an hour before spinal anesthesia (SA) as per the groups assigned and preloaded accordingly. After SA, the incidence of SAIH, the requirement of vasopressor, and fluid were recorded, and side effects were managed. Results: In group IVC, the incidence of SAIH (36.84%), mean dose (3.51 ± 5.02 µg), and mean boluses (0.44 ± 0.63) of norepinephrine required to manage hypotension were significantly lower than in group IJV, and the mean goal directed fluid administered before LSCS (504.46 ± 181.48 ml) and overall mean total fluid (1104.39 ± 160.99 ml) administered were significantly higher than in group IJV. Except for shivering, the incidence of all other complications was significantly lower in group IVC (p &lt; 0.05). Conclusion: Both IVCCI and IJVCI guided preloading are effective in combating SAIH during LSCS, but IVCCI is comparatively better than IJVCI for CI guided preloading.

Dose-Response Study of Norepinephrine Infusion for Maternal Hypotension in Preeclamptic Patients Undergoing Cesarean Delivery Under Spinal Anesthesia.

Spinal anesthesia remains the preferred mode of anesthesia for preeclamptic patients during cesarean delivery. We investigated the incidence of maternal hypotension under spinal anesthesia during cesarean delivery, by comparing different prophylactic infusion rates of norepinephrine with normal saline. We randomly allocated 180 preeclamptic patients (45 in each groups) aged 18-45 scheduled for cesarean delivery to receive one of four prophylactic norepinephrine infusions at doses of 0 (normal saline group), 0.025 (0.025 group), 0.05 (0.05 group), or 0.075 (0.075 group) µg/kg/min following spinal anesthesia. The primary endpoint was the incidence of maternal hypotension (systolic blood pressure < 80% of baseline). The incidence of maternal hypotension was reduced with different prophylactic infusion rates of norepinephrine (26.7%, 15.6%, and 6.7%) compared with normal saline (37.8%) with a significant decreasing trend (p = 0.002). As the infusion doses of norepinephrine increased, there is a significant decreasing trend in deviation of systolic blood pressure control (median performance error; median absolute performance error) from baseline (p < 0.001; p < 0.001) and need for rescue norepinephrine boluses (p = 0.020). The effective dose 50 and effective dose 90 of prophylactic norepinephrine infusion were - 0.018 (95% confidence interval - 0.074, 0.002) µg/kg/min and 0.065 (95% confidence interval 0.048, 0.108) µg/kg/min, respectively. Prophylactic infusion of norepinephrine, as compared to no preventive measures, can effectively reduce the incidence of maternal hypotension in preeclamptic patients under spinal anesthesia during cesarean delivery, without increasing other adverse events for either the mother or neonate. Clinical trials.gov identifier number NCT04556370.

Comparison of the effect of intravenous phenylephrine and norepinephrine boluses for post-spinal hypotension on neonatal outcome in elective caesarean section: A randomised controlled trial.

There is limited data on the effects of norepinephrine on neonatal outcomes and maternal complications relative to other vasopressors. The study aimed to compare neonatal outcomes and maternal complications after bolus intravenous doses of phenylephrine and norepinephrine for post-spinal hypotension in elective caesarean section women. This randomised study was done on 100 elective caesarean section women under spinal anaesthesia. Block randomisation divided women into two groups to receive intravenous phenylephrine 50 μg bolus (Group A) or norepinephrine 5 μg bolus (Group B) following post-spinal hypotension. Groups were evaluated and compared for umbilical arterial blood gas analysis, birth weight, APGAR (appearance, pulse, grimace, activity, and respiration) score, maternal haemodynamics, and complications. Kolmogorov-Smirnov and Shapiro-Wilk tests were used to verify data normality. Independent samples t-test or Mann-Whitney U test was employed to compare continuous variables based on data normality, and the Chi-square test was used to determine categorical variable associations. Demographic characteristics of women were found to be comparable between groups. Umbilical arterial potential of hydrogen, partial pressure of oxygen, partial pressure of carbon dioxide, base excess, bicarbonate, birth weight, and APGAR scores were comparable across groups, showing no significant differences (P > 0.05). Groups had similar maternal haemodynamic characteristics and episodes of nausea, vomiting, and chest pain across groups without statistical significance (P > 0.05). No notable distinction was found between neonatal outcomes and maternal complications between phenylephrine and norepinephrine bolus regimens. Norepinephrine can be used as an alternative to phenylephrine post-spinal hypotension in women undergoing elective caesarean section.

Comparison Between 3 Different Norepinephrine Bolus Doses for Management of Postspinal Hypotension During the Caesarean Section for Patients with Preeclampsia: A Randomized Controlled Trial

Background: There is no established dose for norepinephrine (NE) in the management of postspinal hypotension. The data on its use in women with preeclampsia (PE) are limited. Objectives: This study aimed to compare the effect of using different NE bolus doses for the management of postspinal hypotension during lower segment cesarean section for patients with PE. Methods: This randomized, double-blind trial included mothers with PE scheduled for cesarean delivery who developed postspinal hypotension. Sixty participants were allocated to receive 3, 4, or 5 µg of NE bolus. The primary outcome was the neonatal bicarbonate level. The secondary outcomes were successful management of hypotension, incidence of reactive hypertension, nausea, vomiting, systolic blood pressure (SBP), and heart rate (HR) readings through the operation, umbilical blood gases, and Apgar scores. Results: The number of hypotensive episodes, bradycardia episodes, successfully treated hypotensive episodes, and total NE dose per patient were lower in the 4- and 5-µg groups compared with the 3-µg group. Systolic blood pressure was generally higher in the 4- and 5-µg groups than in the 3-µg group starting from 12 min postspinal till 28 min postspinal. The heart rate decreased compared to the baseline reading starting from 4, 6, and 2 min postspinal in the 3-, 4-, and 5-µg groups, respectively, till 28 min postspinal. Also, HR was higher in the 4- and 5-µg groups compared to the 3-µg group at 6-12 min postspinal. Following the first NE bolus, SBP remained lower than the baseline reading in the 3 groups, and HR decreased compared to the baseline reading in the 3- and 5-µg groups only. Conclusions: The 3-, 4-, and 5-µg doses had comparable efficacy in managing the first hypotensive episode and comparable neonatal outcomes. The 4- and 5-µg doses significantly decreased the total NE requirements and the number of hypotensive episodes. The incidence of maternal bradycardia was not significantly different between the groups.

A Prospective Randomized Double Blind Comparative Study to Determine the Efficacy of Norepinephrine and Ephedrine to Maintain Arterial Blood Pressure During Spinal Anesthesia for Cesarean Delivery

Background: Spinal Anesthesia Induced Hypotension(SAIH) continues to be the troublesome complication for obstetric patients undergoing cesarean section under subarachnoid block. Vasopressors are emerging as the cornerstone of treating SAIH in cesarean section patients with the evolving evidence of arterial vasodilatation as the primary cause of hypotension. This study was hypothesized to compare the efficacy of norepinephrine and ephedrine boluses to maintain hemodynamics in cesarean section.&#x0D; Methods: After approval from institutional ethics committee and registration in Clinical Trials Registry India(CTRI ) and informed consent, study was conducted in 110 healthy parturients aged 18-40 years, belonging to ASA physical status I and II, posted for elective cesarean section under spinal anesthesia, were randomly allocated into group N(n=55) and group E(n=55),who received intravenous boluses of norepinephrine 6 g and ephedrine 10mg respectively as prophylaxis(one dose soon after induction) and in treatment of SAIH. The number of vasopressor boluses were recorded as primary objective and hemodynamics, APGAR scores, adverse events were noted.&#x0D; Results: The number of boluses of vasopressor used was 1.9±1.2 for Ephedrine and 4.72±2.9 for Norepinephrine. At 30,40,50 and 60 minutes after anesthesia, there was significant fall in mean arterial pressure in the norepinephrine group compared to ephedrine group. The incidence of tachycardia was more in ephedrine group and incidence of bradycardia was more in norepinephrine group.&#x0D; Conclusion: Both the study drugs, ephedrine and norepinephrine are comparably effective in preventing SAIH after prophylactic bolus and effective in maintaining blood pressure intraoperatively, more number of boluses of norepinephrine was required compared to ephedrine.

Norepinephrine boluses for the prevention of post-reperfusion syndrome in living donor liver transplantation: A prospective, open-label, single-arm feasibility trial.

Post-reperfusion syndrome (PRS) is a serious haemodynamic event during liver transplantation (LT), which increases early graft dysfunction and mortality. This study aimed to test the efficacy and safety of norepinephrine (NE) boluses to prevent PRS during orthotopic LT. This feasibility phase II trial prospectively recruited a single arm of 40 patients undergoing living donor LT. The intervention was an escalated protocol of NE boluses starting at 20 µg. The primary outcome was the incidence of PRS. The secondary outcomes were arrhythmia, electrocardiographic (EKG) ischaemic changes, mean pulmonary pressure after reperfusion, 3-month survival and 1-year survival. PRS occurred in 28 (70%) cases [95% confidence interval (CI) 54% to 83%, P < 0.001], with a relative risk reduction of 0.22 when compared to our previous results (90%). Twelve cases developed transient EKG ischaemic changes. All EKG ischaemic changes returned to baseline after correction of hypotension. There was no significant arrhythmia or bradycardia (95% CI 0 to 0.9). After reperfusion, the mean pulmonary artery pressure was not significantly higher than the normal limit (20 mmHg) (P = 0.88). The 3-month survival was 0.95 (95% CI 0.83 to 0.99), and the 1-year survival was 0.93 (95% CI 0.8 to 0.98). Our findings suggest that NE boluses starting with 20 μg is feasible and effective in lowering the risk of PRS during living donor LT. Additionally, NE boluses were not associated with significant myocardial ischaemic events, arrhythmia or a rise in pulmonary pressure.

Post-spinal hypotension management for cesarean section in low resource settings: efficiency and safety of two very low-dose boluses of norepinephrine, a randomized double-blinded controlled trial

Spinal anesthesia is the gold standard anesthetic technique for cesarean section. However, its major complication is hypotension. Norepinephrine has recently been described as an efficient and safe alternative to Phenylephrine. The aim of this study was to determine the effective target bolus of Norepinephrine to prevent and treat post-spinal anesthesia hypotension. We conducted a prospective controlled randomized study including 126 parturients scheduled for cesarean delivery under spinal anesthesia. We compared two groups that received a prophylactic bolus of either 1μg/kg or 0.5μg/kg of Norepinephrine without fluid loading. The rescue intravenous bolus of Norepinephrine was half the dose of the prophylactic bolus. The main outcomes were the percentage of decrease in systolic and mean blood pressure. The secondary outcomes included the timing of the first hypotension, duration of hypotension, number of rescue boluses, total Norepinephrine consumption, incidence of hypotension and maternal adverse effects and fetal outcomes. Our primary outcome has shown similarities between groups; delta systolic blood pressure before delivery was 19.4% in group 1µg/kg versus 20.5% in group 0.5µg/kg. Both groups were similar for all secondary outcomes, except that the higher dose of Norepinephrine resulted in more hypertension. Fetal outcomes were similar in both groups. Bolus of 0.5μg/kg followed by rescue doses of 0.25μg/kg of Norepinephrine was efficient in preventing and treating spinal anesthesia-induced hypotension. These doses may be recommended for routine use in healthy parturients.

Effectiveness of norepinephrine versus phenylephrine intravenous boluses for the treatment of hypotension in elective lower-segment cesarean section under spinal anesthesia: A randomized controlled, double-blind study

Abstract Background and Aim: Hypotension following spinal anesthesia is a common adverse effect during caesarean sections, with potentially harmful consequences for both the mother and the fetus. While phenylephrine is the current first-line treatment for maternal spinal hypotension during obstetric anesthesia, norepinephrine has been proposed as a possible alternative due to its weaker b-agonist-mediated positive chronotropic action. However, there is a lack of comparative data on the safety and efficacy of these two drugs in obstetric anesthesia. This study aimed to compare the number of bolus doses of phenylephrine and norepinephrine required to treat hypotension after spinal anesthesia in lower segment caesarean sections, as well as to evaluate maternal and fetal outcomes in both groups, including complications. Materials and Method: A prospective double-blinded randomized controlled trial was conducted, The study included 60 term parturients between the ages of 18 and 40, who had singleton pregnancy and were categorized as American Society of Anaesthesiologists (ASA) physical class II, and who were scheduled for elective caesarean section under spinal anesthesia. the parturients were randomized into two groups: Group N and Group P. Group P patients received an intravenous dose of phenylephrine 100 µg, while Group N patients received an intravenous dose of 8 µg whenever the systolic arterial pressure dropped below 20% of the baseline.primary objective was number of intravenous drugs required to treat spinal hypotension, secondary objective were incidence of maternal and foetal Complications. The data was collected on a form and entered into Excel. Statistical analysis was done using Epi Info 7.2.1.0 for Windows. The Kolmogorov-Smirnov test was used to check normality. Mean and standard deviation or median and range were used to present numerical data, while frequency and percentage were used for categorical data. T-tests compared quantitative variables, and Chi-square tests compared categorical data. Two-tailed tests were used, and a P-value of &lt;0.05 was considered significant. Result: The patient’s demographic profile was comparable in both groups.T he number of bolus doses of study drug required to treat spinal hypotension was significantly lower in Group N versus P (1.50 ± 0.57 vs. 2.13 ± 0.73, p =0.001)Incidence of bradycardia was more in group P, but not statistically significant. Other maternal complications like bradycardia, hypertension, nausea, vomiting, shivering were comparable in both groups. Conclusions: According to our study, Intermittent boluses of norepinephrine were effective in the management of spinal-induced hypotension during caesarean section. Norepinephrine boluses can thus be considered as an alternative to phenylephrine boluses.

Comparison of efficacy of low-dose norepinephrine infusion with low-dose boluses of norepinephrine in managing hypotension among parturients undergoing caesarean section under the subarachnoid block

: Spinal anesthesia is increasingly popular over general anesthesia due to several advantages. Hypotension can complicate spinal anesthesia during a cesarean section, which could have negative repercussions on the mother and fetus. This study is aimed to compare the efficacy of low-dose norepinephrine infusion with low-dose boluses of norepinephrine in managing hypotension among parturients undergoing cesarean section under subarachnoid block.: Ninety-nine parturients without comorbidities who underwent caesarean section with spinal anesthesia received norepinephrine were considered. They were divided into three groups. Group A- Parturient received a norepinephrine infusion of 1 mcg/min and a rescue bolus of 3 mcg to treat hypotension. Group B- Parturient received a Norepinephrine bolus of 3mcg to treat hypotension. Group C- Parturient received a Norepinephrine bolus of 5 mcg to treat hypotension. All the vitals at different intervals, number of norepinephrine boluses, the total amount of norepinephrine consumed, maximum sensory level achieved, time for baby extraction following subarachnoid block, and any adverse events were documented.No statistical difference was noted in the study group's demographics. However, there was a significant difference in mean systolic blood pressure between the groups from skin incision to baby extraction at T6 and T8. In addition, the mean arterial blood pressure of the two groups differed significantly throughout the period from baby extraction to skin suturing. Between the groups, there was a substantial difference in the total number of boluses needed. The total number of boluses required was maximum in group B, followed by group C. Group A required the minimum number of total norepinephrine boluses.A prophylactic norepinephrine infusion is an effective and straightforward method of reducing the incidence and magnitude of hypotension following spinal anesthesia for cesarean section with no adverse effect.

Preventing Spinal Hypotension During Cesarean Birth With 2 Initial Boluses of Norepinephrine in Chinese Parturients: A Randomized, Double-blind, Controlled Trial

(Anesth Analg. 2023;136:94–100) Spinal hypotension is a common adverse outcome during cesarean delivery and impacts 70% to 80% of mothers. Norepinephrine has proven effective in preventing spinal hypotension, however, the optimal regimen of norepinephrine has yet to be determined. This study hypothesized an initial norepinephrine bolus helps prevent spinal hypotension compared with continuous norepinephrine alone. The aim of this study was to compare 2 loading boluses of norepinephrine (0.05 and 0.10 μg/kg) followed by regular 0.05 μg/kg/min infusion during cesarean delivery in ability to prevent spinal hypotension using noninvasive blood pressure measurements.

Comparison of the hemodynamic effects of opioid-based versus lidocaine-based induction of anesthesia with propofol in older adults: a randomized controlled trial

BackgroundThe present study aims to compare the hemodynamic profile of lidocaine and fentanyl during propofol induction of general anesthesia. MethodsThis randomized controlled trial included patients aged above 60 years undergoing elective non-cardiac surgery. The included patients received either 1 mg/kg lidocaine (n = 50) or 1 mcg/kg fentanyl (n = 50) based on total body weight with propofol induction of anesthesia. Patient’s hemodynamics were recorded every minute for the first 5 min then every 2 min until 15 min after induction of anesthesia. Hypotension (mean arterial pressure [MAP] <65 mmHg or >30% reduction from baseline) was treated by intravenous 4 mcg bolus of norepinephrine. Outcomes included norepinephrine requirements (primary), the incidence of postinduction hypotension, MAP, heart rate, intubation condition, and postoperative delirium via the cognitive assessment method. ResultsForty-seven patients in the lidocaine group and 46 patients in the fentanyl group were analyzed. None in the lidocaine group experienced hypotension, while 28/46 (61%) of patients in the fentanyl group developed at least one episode of hypotension requiring a median (25th and 75th quartiles) norepinephrine dose of 4 (0,5) mcg, p-value <0.001 for both outcomes. The average MAP was lower in the fentanyl group than in the lidocaine group at all time points after anesthesia induction. The average heart rate was comparable between the two groups nearly at all time points after anesthesia induction. The overall intubation condition was comparable between the two groups. None of the included patients developed postoperative delirium. ConclusionLidocaine-based regimen for induction of anesthesia reduced the risk of postinduction hypotension in older patients compared to the fentanyl-based regimen.

Comparison of norepinephrine bolus versus infusion for prevention of post-spinal hypotension in parturients with preeclampsia undergoing cesarean section

Background: Currently, spinal anesthesia for cesarean section is the anesthetic technique of choice for women with preeclampsia in the absence of contraindications to neuraxial anesthesia. Recently, norepinephrine has been introduced for prevention and treatment of hypotension associated with spinal anesthesia; however, only a couple of studies have compared norepinephrine infusion and bolus. Aims: This study aims to compare primarily the efficacy and safety of norepinephrine bolus given therapeutically and norepinephrine infusion given prophylactically for management of hypotension and effects on other hemodynamic parameters in parturients with preeclampsia undergoing cesarean section under spinal anesthesia and secondarily to determine the effects of study drugs on neonatal Apgar score and arterial blood gas analysis of neonatal blood. Methods: In this prospective randomized study, 100 singleton full-term pregnant females of ASA grade II, aged 18–35 years, diagnosed with preeclampsia (controlled on single antihypertensive drug with BP ≤140/90), scheduled for elective cesarean section under spinal anesthesia were randomly divided into two groups. Group A: Received therapeutic norepinephrine bolus (4 mg) only when hypotension (fall in SBP to ≤20% of baseline) was detected after spinal anesthesia. Group B: Received prophylactic intravenous norepinephrine infusion (4 mg/min) immediately after induction of spinal anesthesia. Results: Heart rate, systolic, diastolic, and mean blood pressure had statistically significant difference at 3,4,5,6,7,8,9, and 10 mins of surgery. Number of episodes of hypotension and number of norepinephrine boluses used in Group A were higher and statistically significant (p-value < 0.001) than Group B. Apgar score at 1 and 5 minutes as well as umbilical artery parameters in two groups was comparable and statistically insignificant (p-value 0.301 for Apgar at 1 min and P value 0.562 for Apgar at 5 mins). Conclusion: Although both norepinephrine bolus and infusion doses are an effective way to treat spinal anesthesia-related hypotension in patients with preeclampsia undergoing cesarean section with comparable maternal and fetal side effects, infusion dose of norepinephrine is better in maintaining hemodynamics of parturients with insignificant changes in neonatal outcomes.

Effects of prophylactic bolus of norepinephrine versus phenylephrine on maternal and fetal outcome during caesarean section under subarachnoid block: A randomized study

Background: Vasopressors are the mainstay of treatment of subarachnoid block-induced hypotension (SAIH). The literature is ambiguous regarding the choice of vasopressor, the strategy of administration, and their potency ratio for proper comparison. A prophylactic bolus dosing is the preferred mode of administration for obstetric anesthesia. Thus, we undertook a study to assess the efficacy of norepinephrine (NE) and phenylephrine (PE) in preventing SAIH and compare their effects on maternal and fetal outcomes. Materials and Methods: A randomized, double-blind clinical study was conducted on 240 parturients planned for elective cesarean section under subarachnoid block (SAB). They were allocated to receive a prophylactic bolus dose of either NE 4 μg or PE 50 μg immediately after the SAB. The incidence of maternal hypotension (primary outcome); heart rate (HR), reactive hypertension, intraoperative nausea or vomiting, neonatal APGAR score, umbilical umblical cord blood pH, and the need for active neonatal resuscitation (secondary outcomes) was compared between the groups. Results: The incidence of hypotension was comparable between the groups (P = 0.42). The mean HR was significantly higher in the NE group at 2 min (83.9 ± 9.2 vs. 80.6 ± 9.3 bpm, P = 0.005), 3 min (84.4 ± 8.8 vs. 79.3 ± 11.1 bpm, P < 0.001) and 4 min (85.0 ± 9.9 vs. 79.6 ± 12.6 bpm, P < 0.001). Rest of the maternal and fetal outcomes were similar in both the groups. Conclusion: Based on the relative potency ratio of 12.5, the effect of an intermittent prophylactic bolus dose of NE is comparable to that of PE in preventing SAIH.

Comparison of norepinephrine and phenylephrine boluses during spinal anesthesia for cesarean delivery

Background: Cesarean sections are frequently carried out under spinal anesthesia (SA) to reduce the risk of neonatal drug transfer and airway difficulties associated with general anesthesia. Maternal hypotension is a typical consequence following SA, despite sufficient fluid loading. Aims and Objectives: The aim of this study was to evaluate the efficacy of norepinephrine and phenylephrine in treating spinal hypotension caused by cesarean delivery. Materials and Methods: This hospital-based interventional study was carried out at Sri Venkateswaraa Medical College Hospital and Research Centre, Ariyur, Puducherry from February 2020 to March 2022. Eighty patients were included in our trial and were split equally into two groups at random following approval by an ethical committee and written informed consent. Age, weight, height, and American Society of Anesthesiologists physical state of the patients was equivalent across the two groups. Results: In our study, mean age found in N group (25.96±2.046) and P group (24.84±1.748) which were insignificant. Vasopressor bolus dose needed for the treatment of hypotension was considerably less inGroup N patients (1.71±0.77 vs. 2.43±1.01, P=0.024). Group P had a higher incidence of bradycardia, although the difference was statistically insignificant (four patients vs. eight patients P=0.242). The fetal parameters such as birth weight, umbilical PH, PCO, PO2, and Apgar 1 and 5 min were comparable across the two groups, and no statistically significant differences were found. Conclusion: Intermittent norepinephrine boluses are a successful treatment for spinal hypotension during cesarean delivery. We found no evidence that norepinephrine had a detrimental effect on the newborn outcome as compared to phenylephrine, when used to maintain blood pressure during spinal and combined spinalepidural anesthesia for cesarean birth.

Appraisal of the Effect of Norepinephrine Versus Phenylephrine on Blood Pressure and Heart Rate During Spinal Anaesthesia for a Caesarean Section; A Quasi-Experimental Study

Objectives: To compare the effects of Norepinephrine and Phenylephrine on blood pressure and heart rate during spinal anaesthesia for caesarean section.&#x0D; Study Design: Quasi-experimental study.&#x0D; Place and Duration of Study: Department of Anaesthesia Combined Military Hospital, Multan Pakistan, from May to Nov 2019.&#x0D; Methodology: Women (age: 18 to 45 years) with singleton pregnancy planned for caesarean section in spinal anaesthesia were included. Women with pregnancy-induced hypertension, placenta previa, placenta accreta, diabetes mellitus, and any other cardiovascular disease were excluded. After distribution into groups, Group-A was given a 20μg Norepinephrine bolus, and Group-B was given a 50μg bolus of Phenylephrine just after spinal anaesthesia. At five time points, systolic, diastolic, and mean blood pressures and heart rate were measured: baseline, block of the highest sensory level, oxytocin injection, delivery, and operation completion. If hypotension developed, the same rescue drug was repeated. Bradycardia was countered by 0.5 mg of Atropine.&#x0D; Results: The frequency of hypotension in the Norepinephrine group was 5 (16.67%), and in the Phenylephrine Group, it was 19 (63.33%) (p=0.0001). The frequency of bradycardia in the Norepinephrine Group was 6 (20%), and in the Phenylephrine Group, it was 17 (56.67%) (p=0.003).&#x0D; Conclusion: The frequency of hypotension and bradycardia is less after prophylactic 20 μg of Norepinephrine during spinal anaesthesia for a caesarean section than 50 μg of Phenylephrine.

Effects of norepinephrine infusion during cardiopulmonary bypass on perioperative changes in lactic acid level (Norcal).

Hyperlactatemia, a problem reported in up to 30% of cardiac surgery patients, results from excessive production of or decreased clearance of lactate. It is typically a symptom of tissue hypoperfusion and may be associated with the prevalence of postoperative acute mesenteric ischemia and renal failure, or prolonged intensive care unit (ICU) and hospital stay, and increased 30-day mortality. Eighty cardiac surgery patients using cardiopulmonary bypass (CPB) were randomly assigned into either a placebo (n = 39) or norepinephrine 0.05-0.2 µg/kg/min (n = 41) as well as norepinephrine boluses during CPB to maintain mean arterial blood pressure (MAP) at 65 to 80 mm Hg. Patient assignments were done after receiving ethical approval to proceed. The primary result was the perioperative changes in lactic acid level. Secondary findings were also recorded, including hemodynamic variables, the incidence of vasoplegia, intraoperative hypotension, myocardial ischemia, the need for vasopressor support, postoperative complications, and mortality. The peak levels and perioperative changes in blood lactate during the first 24 postoperative hours, the number of patients who experienced early hyperlactatemia on admission to the ICU (Placebo: 46.2%, Norepinephrine: 51.2%, p = .650), vasoplegia, hemodynamic changes, incidences of intraoperative hypotension, myocardial ischemia, postoperative complications, and mortality rates were similar in the two groups. Patients in the norepinephrine group received lower intraoperative rescue norepinephrine boluses to maintain the target MAP (p = .039) and had higher MAP values during the CPB and intraoperative blood loss [mean difference [95% confidence interval]; 177 [20.9-334.3] ml, p = .027]. norepinephrine and placebo infusions during the CPB with the maintenance of MAP from 65 to 80 mmHg had comparative effects on the changes in blood lactate and incidence of vasoplegia after cardiac surgery. Norepinephrine infusion maintained higher MAP values during the CPB.

Comparative study on the manually-controlled variable-rate versus fixed-rate infusion of norepinephrine for preventing hypotension during spinal anesthesia for cesarean delivery

Study objectivePrevious studies have shown that prophylactic norepinephrine infusion is superior to intermittent bolus administration in preventing post-spinal hypotension. Nevertheless, it is still controversial whether manually-controlled variable-rate infusion is more effective than fixed-rate infusion. The purpose of the present study was to compare the efficacy of variable-rate infusion and fixed-rate infusion of norepinephrine for prophylaxis against maternal hypotension and maintaining hemodynamic stability during spinal anesthesia for cesarean delivery to determine more effective mode for clinical practice. DesignA prospective randomized, controlled study. SettingOperating room, Women's Hospital, Zhejiang University School of Medicine. PatientsA total of 161 parturients scheduled for elective cesarean delivery with spinal anesthesia were randomized into Group F (fixed-rate infusion) and Group V (variable-rate infusion). InterventionsParturients received prophylactic norepinephrine infusion concurrent with the intrathecal injection at rate started at 0.05 μg/kg/min. In Group F, norepinephrine was administered continuously at a fixed (on-off) rate, and a bolus of norepinephrine 5 μg or 10 μg was given when systolic blood pressure (SBP) decreased by 20% or more of baseline. In Group V, manually adjusted norepinephrine infusion within the range 0–0.14 μg/kg/min, according to SBP at 1-min intervals until delivery, aim to maintain values close to the baseline. MeasurementsDuring the study period, the incidence of maternal hypotension, hemodynamic performance, the number of physician interventions, reactive hypertension, bradycardia, nausea, vomiting, norepinephrine cumulative dose (before delivery), and neonatal outcomes were recorded. Main resultsThe incidence of maternal hypotension was significantly lower in Group V than that in Group F (9% versus 30%) (P < 0.001). No significant difference was found in the serial changes in SBP and heart rate (HR) for the first 15 min. Group V showed higher frequency of physician interventions compared with the Group F (P < 0.001). The incidence of hypertension, severe hypotension, nausea, vomiting, bradycardia, norepinephrine cumulative dose, and neonatal outcome were comparable between the two groups. ConclusionWhen norepinephrine was infused at an initial dose of 0.05 μg/kg/min for preventing hypotension during spinal anesthesia for cesarean delivery, due to technical limitations of inadequate dose design in this study, neither a variable-rate infusion (need more physician intervention) nor a fixed-rate infusion regimen (experience more transient hypotension) was optimal. However, in terms of clinical importance, how to prevent the parturients from experiencing more incidence of hypotension might be a greater concern for anesthesiologists.

A Prospective Randomized Study Comparing the Bolus Doses of Norepinephrine and Phenylephrine for the Treatment of Spinal Induced Hypotension in Cesarean Section.

Background: Spinal anesthetic-induced hypotension is the most worrisome complication for patients undergoing cesarean section under spinal anesthesia. The present study compares norepinephrine and phenylephrine bolus for the treatment of hypotension during spinal anesthesia for cesarean section.Methods: One hundred twenty- six women aged between 22 and 40 years with singleton pregnancy classified to the American Society of Anesthesiologists (ASA) physical class I and II posted for elective cesarean section under spinal anesthesia were randomly divided into two groups of 63 each. Group I patients received phenylephrine 50 mcg (microgram) as an intravenous bolus, and Group II received 4 mcg of norepinephrine as an intravenous bolus to treat spinal hypotension.Results: On comparing the demographic data of the patients in terms of age, weight, height, ASA Grade, level of block and surgery time no significant differences were found between the groups. Similarly, the fetal parameters were found to be not significantly different between the groups. However, the number of bolus doses of vasopressors required for the treatment of spinal-induced hypotension was significantly reduced in Group II (p=0.02). The frequency of bradycardia was found to be higher in patients who were given phenylephrine as compared to patients administered noradrenaline boluses (p=0.03). Five (7.93%) patients had shivering in Group I, while similar episodes were observed in 10 (15.87%) patients (p=0.05). Moreover, no significant difference was observed in comparing the heart rate and mean arterial pressure between the groups.Conclusion: Intermittent boluses of norepinephrine are found to be effective in the management of spinal‑induced hypotension during caesarean section.