EDITOR’S PERSPECTIVE What We Already Know about This Topic Hypotension after spinal anesthesia for cesarean delivery is common, usually treated with phenylephrine or ephedrine Norepinephrine was recently introduced in obstetric anesthesia but the optimal dose is unknown What This Article Tells Us That Is New This randomized, double-blinded trial compared prophylactic norepinephrine infusions of 0.025, 0.050, or 0.075 μg · kg-1 · min-1, started after bupivacaine spinal anesthesia, in full-term parturients having elective cesarean delivery The primary outcome, maternal hypotension (systolic blood pressure less than 80% of baseline), occurred less frequently after both 0.050 and 0.075 μg · kg-1 · min-1 compared 0.025 μg · kg-1 · min-1 norepinephrine Background Norepinephrine has been recently introduced for prophylaxis against postspinal hypotension during cesarean delivery; however, no data are available regarding its optimum dose. The objective of this study is to compare three infusion rates of norepinephrine for prophylaxis against postspinal hypotension during cesarean delivery. Methods The authors conducted a double-blinded, randomized, controlled study including full-term pregnant women scheduled for cesarean delivery. Norepinephrine infusion was commenced after subarachnoid block. Patients were randomized into three groups, which received norepinephrine with starting infusion rates of 0.025 μg · kg-1 · min-1, 0.050 μg · kg-1 · min-1, and 0.075 μg · kg-1 · min-1. Infusion was stopped when intraoperative hypertension occurred. The primary outcome was the frequency of postspinal hypotension (defined as decreased systolic blood pressure less than 80% of the baseline reading). The three groups were compared according to the following: systolic blood pressure, heart rate, frequency of intraoperative hypertension, frequency of bradycardia, and neonatal outcomes. Results Two hundred eighty-four mothers were included in the analysis. The frequency of postspinal hypotension was lower for both the 0.050-μg · kg-1 · min-1 dose group (23/93 [24.7%], odds ratio: 0.45 [95% CI: 0.24 to 0.82], P = 0.014) and the 0.075-μg · kg-1 · min-1 dose group (25/96 [26.0%], odds ratio: 0.48 [95% CI:0.26 to 0.89], P = 0.022) compared with the 0.025-μg · kg-1 · min-1 dose group (40/95 [42.1%]). The two higher-dose groups (the 0.050-μg · kg-1 · min-1 group and the 0.075-μg · kg-1 · min-1 group) had higher systolic blood pressure and lower heart rate compared with the 0.025 μg · kg-1 · min-1 group. The three groups were comparable in the frequency of intraoperative hypertension, incidence of bradycardia, and neonatal outcomes. Conclusions Both the 0.050-μg · kg-1 · min-1 and 0.075-μg · kg-1 · min-1 norepinephrine infusion rates effectively reduced postspinal hypotension during cesarean delivery compared with the 0.025-μg · kg-1 · min-1 infusion rate.

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BackgroundDexmedetomidine infusion improves oxygenation and lung mechanics in patients with chronic obstructive lung disease; however, its effect in patients with restrictive lung disease has not been thoroughly investigated yet. The aim of this work was to evaluate the effects of dexmedetomidine infusion on oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease.MethodsForty-two morbidly obese patients scheduled for bariatric surgery were included in the study. Patients were randomized to receive either dexmedetomidine infusion at a bolus dose of 1mcg/Kg followed by infusion at 1 mcg/Kg/hour for 90 min (Dexmedetomidine group), or normal saline infusion (Control group). Both groups were compared with regard to: oxygenation {P/F ratio: PaO2/fraction of inspired oxygen (FiO2)}, lung compliance, dead space, plateau pressure, blood pressure, and heart rate.ResultsDexmedetomidine group showed significant improvement of the PaO2/FiO2 ratio, and higher lung compliance compared to control group by the end of drug infusion. Dexmedetomidine group demonstrated decreased dead space, plateau pressure, blood pressure, and heart rate compared to control group by the end of drug infusion.ConclusionA 90-min dexmedetomidine infusion resulted in moderate improvement in oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease.Trial registrationclinicaltrials.gov: NCT02843698 on 20 July 2016.

Background: Endotracheal intubation requires optimum position of the head and neck. In obese females, the usual ramped position might not provide adequate intubating conditions. We hypothesized that a new position, termed modified-ramped position, during induction of anesthesia would facilitate endotracheal intubation through bringing the breasts away from the laryngoscope and would also improve the laryngeal visualization. Methods: Sixty obese female patients scheduled for general anesthesia were randomly assigned into either ramped or modified-ramped position during induction of anesthesia. In the ramped position (n = 30), the patient head and shoulders were elevated to achieve alignment of the sternal notch and the external auditory meatus; while in the modified-ramped position (n = 30), the patient shoulders were elevated using a special pillow, and the head was extended to the most possible range. Our primary outcome was the incidence of failed laryngoscopic insertion in the oral cavity (the need for patient repositioning). Other outcomes included time till vocal cord visualization, time till successful endotracheal intubation, difficulty of the mask ventilation, and Cormack-Lehane grade for laryngeal view. Results: Fourteen patients (47%) in ramped group required repositioning to facilitate introduction of the laryngoscope in the oral cavity in comparison to one patient (3%) in the modified-ramped position (p < 0.001). Modified-ramped position showed lower incidence of difficult mask ventilation, shorter time for glottic visualization, and shorter time for endotracheal tube insertion compared to the ramped position. The Cormack-Lehane grade was better in the modified-ramped position. Conclusion: Modified-ramped position provided better intubating conditions, improved the laryngeal view, and eliminated the need for repositioning of obese female patients during insertion of the laryngoscope compared to ramped position. Clinical trial registration: Identifier: NCT03640442. Date: August 2018.

Background: Data on the best norepinephrine bolus dose for management of hypotension are limited. The aim of this study was to compare the efficacy and safety of two norepinephrine bolus doses in the rescue management of maternal hypotension during cesarean delivery. Methods: This randomized, controlled trial included mothers scheduled for cesarean delivery with spinal anesthesia with a prophylactic norepinephrine infusion. Following spinal anaesthesia administration, a participant was considered hypotensive if systolic blood pressure was ≤80% compared to the baseline reading. Participants were allocated to receive either 6 mcg or 10 mcg norepinephrine bolus for the management of hypotensive episodes. The hemodynamic response after administration of norepinephrine bolus was recorded. The episode was considered successfully managed if systolic blood pressure returned to within 80% from the baseline reading within 2 min after norepinephrine bolus administration, and did not drop again within 6 min after the norepinephrine bolus. The primary outcome was the incidence of successful management of the first hypotensive episode. Other outcomes included systolic blood pressure, heart rate, incidence of maternal bradycardia, and reactive hypertension. Results: One hundred and ten mothers developed hypotensive episodes and received norepinephrine boluses for management. The number of successfully managed first hypotensive episodes was 50/57 (88%) in the 6 mcgtreated episodes and 45/53 (85%) in the 10 mcg-treated episodes (p = 0.78). Systolic blood pressure was comparable after administration of either bolus dose. Heart rate was lower after administration of 10 mcg bolus compared to 6 mcg bolus, without significant bradycardia requiring atropine administration. The incidence of reactive hypertension was comparable between both groups.

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BackgroundPhenylephrine is the most commonly used vasopressor for prophylaxis against maternal hypotension during cesarean delivery; however, the best regimen for its administration is not well established. Although variable infusion protocols had been suggested for phenylephrine infusion, evidence-based evaluation of variable infusion regimens are lacking. The aim of this work is to compare variable infusion, fixed on-and-off infusion, and intermittent boluses of phenylephrine for prophylaxis against maternal hypotension during cesarean delivery.MethodsA randomized controlled study was conducted, including full-term pregnant women scheduled for elective cesarean delivery. Participants were divided into three groups which received phenylephrine by either intermittent boluses (1.5 mcg/Kg phenylephrine), fixed on-and-off infusion (with a dose of 0.75 mcg/Kg/min), or variable infusion (with a starting dose of 0.75 mcg/Kg/min). The three groups were compared with regard to frequency of: maternal hypotension (primary outcome), second episode hypotension, reactive hypertension, and bradycardia. Other outcomes included heart rate, systolic blood pressure, physician interventions, and neonatal outcomes.ResultsTwo-hundred and seventeen mothers were available for final analysis. The 2 infusion groups showed less incidence of maternal hypotension {26/70 (37%), 22/71 (31%), and (51/76 (67%)} and higher incidence of reactive hypertension compared to the intermittent boluses group without significant differences between the two former groups. The number of physician interventions was highest in the variable infusion group compared to the other two groups. The intermittent boluses group showed lower systolic blood pressure and higher heart rate compared to the two infusion groups; whilst the two later groups were comparable.ConclusionBoth phenylephrine infusion regimens equally prevented maternal hypotension during cesarean delivery compared to intermittent boluses regimen. Due to higher number of physician interventions in the variable infusion regimen, the current recommendations which favor this regimen over fixed infusion regimen might need re-evaluation.

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