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European Journal of Anaesthesiology Jul 2022
Topics: Humans; Hypotension; Norepinephrine; Phenylephrine; Vasoconstrictor Agents
PubMed: 35759290
DOI: 10.1097/EJA.0000000000001697 -
Drug Design, Development and Therapy 2022Norepinephrine has been associated with improved heart rate (HR) and cardiac output (CO) compared to phenylephrine as a treatment for post-spinal hypotension during... (Randomized Controlled Trial)
Randomized Controlled Trial
Comparison of Prophylactic Norepinephrine and Phenylephrine Infusions During Spinal Anaesthesia for Primary Caesarean Delivery in Twin Pregnancies: A Randomized Double-Blinded Clinical Study.
BACKGROUND
Norepinephrine has been associated with improved heart rate (HR) and cardiac output (CO) compared to phenylephrine as a treatment for post-spinal hypotension during caesarean delivery (CD) in singleton pregnancies. Our current study compared the effects of norepinephrine and phenylephrine in maintaining maternal hemodynamics after spinal anaesthesia in twin pregnancies during elective CD.
METHODS
This was a double-blinded, randomized, controlled study. From December 2017 to December 2018, 62 women with healthy twin term pregnancies undergoing elective CD under spinal anaesthesia were studied. Following spinal induction, either norepinephrine (6 μg/mL) or phenylepinephrine (75 μg/mL) was infused at 60 mL/h to maintain systolic blood pressure (SBP) near baseline until delivery. HR, SBP, systemic vascular resistance (SVR), and CO were collected using anaesthesia monitors and continuous-pulse waveform analysis. The primary outcome was maternal CO. Other parameters of maternal hemodynamics, umbilical cord blood gases, and adverse events were also compared.
RESULTS
Hemodynamic variables (CO, SBP, HR, and SVR) between spinal anaesthesia induction to skin incision were similar between the two groups ( = 0.889, 0.057, 0.977, and 0.416, respectively). The incidence of bradycardia was significantly higher in the phenylephrine group (69%) than in the norepinephrine group (24.2%, <0.001). Maternal nausea and vomiting, hypotension, reactive hypertension, and neonatal outcomes did not differ between the groups.
CONCLUSION
When administered as a prophylactic fixed-rate infusion, phenylephrine and norepinephrine are both capable of maintaining maternal blood pressure following spinal anaesthesia in twin pregnancies. There were no differences in the maternal hemodynamics or foetal outcomes between women receiving norepinephrine and phenylephrine.
PREVIOUS PRESENTATIONS
Presented at the 51st Society for Obstetric Anesthesia and Perinatology Annual Meeting, Phoenix, Arizona, May 1-5, 2019.
CLINICAL TRIAL NUMBER AND REGISTRY
No. ChiCTR-IOR-17013358.
Topics: Anesthesia, Spinal; Cesarean Section; Female; Humans; Infant, Newborn; Norepinephrine; Phenylephrine; Pregnancy; Pregnancy, Twin; Vasoconstrictor Agents
PubMed: 35355656
DOI: 10.2147/DDDT.S357507 -
Journal of Clinical Monitoring and... Jun 2023Different organs have different autoregulatory capacities for blood pressure changes and/or circulatory volume changes. This study assessed the autoregulation of the...
PURPOSE
Different organs have different autoregulatory capacities for blood pressure changes and/or circulatory volume changes. This study assessed the autoregulation of the stomach, liver, kidney and skeletal muscle, under baseline, hypovolemic, and post-fluid-resuscitation conditions using near-infrared spectroscopy (NIRS).
METHODS
Ten pigs (bodyweight 24.5 ± 0.5 kg) were anesthetized with 2.5% isoflurane and administered 0.5, 1, 2 and 5 µg kg min of phenylephrine at 10-min intervals, followed by similar stepwise infusion of sodium nitroprusside (SNP) to induce a wide range of mean arterial pressures (MAPs). A 600-ml bleed was induced to create the hypovolemic condition, and only phenylephrine was re-administered. Hydroxyethyl starch (600 ml) was infused to create the post-fluid-resuscitation condition, and phenylephrine and SNP were re-administered. Average relationships between mean arterial pressure (MAP) and each tissue oxygenation index (TOI) were assessed, and the individual relationships were evaluated based on the correlation coefficients between MAP and TOI during each vasoactive drug infusion.
RESULTS
Based on the evaluation using each TOI as a substitute of blood flow, the kidney autoregulation was robust, similar to muscle, but had a prominent lower limit. The stomach had weaker autoregulation than the kidney and muscle. The liver had no autoregulation. The kidney TOI showed 2-fold greater changes in response to volume condition changes than the stomach and liver TOIs.
CONCLUSION
In our NIRS-based assessment of autoregulatory capacity, the liver oxygenation is highly blood pressure dependent, and the kidney is highly susceptible and the skeletal muscle is highly tolerable to low blood pressure and volume loss.
Topics: Animals; Blood Pressure; Cerebrovascular Circulation; Hypovolemia; Kidney; Liver; Muscle, Skeletal; Phenylephrine; Spectroscopy, Near-Infrared; Stomach; Swine
PubMed: 36596969
DOI: 10.1007/s10877-022-00956-5 -
Journal of Pharmacy Practice Aug 2023During hospitalization, the risk of hypotension and associated sequelae remain important considerations for patient outcomes. The use of push-dose vasopressors (PDP)... (Review)
Review
During hospitalization, the risk of hypotension and associated sequelae remain important considerations for patient outcomes. The use of push-dose vasopressors (PDP) outside of the operating room has increased in recent years to combat the negative effects of hypotension. This narrative review evaluates the utility of PDP in its traditional perioperative setting as well as in areas of increasing use such as the emergency department and intensive care unit. Articles evaluating PDP highlight successful increases in blood pressure with all agents but differ in rates of adverse events and most lack direct comparison of PDP agents in regard to safety and efficacy. Agents utilized as PDP, including epinephrine, phenylephrine, norepinephrine, vasopressin, and ephedrine vary in mechanism of action, onset of action, and duration of action. These variations in pharmacology along with published literature may lead to differences in the preferred PDP for various clinical scenarios. Many adverse events associated with PDP have been due to dosing errors highlighting the importance of education surrounding the use of these agents. Additional research is necessary to further elucidate the risks and benefits of PDP in clinical practice, and to determine which PDP is truly preferred. Careful consideration should be given when determining the appropriateness of this administration method of vasopressors in various clinical scenarios.
Topics: Humans; Vasoconstrictor Agents; Phenylephrine; Epinephrine; Hypotension; Critical Care
PubMed: 35459405
DOI: 10.1177/08971900221096967 -
Journal of Optometry 2019We tested the hypothesis that changes in accommodation after instillation of Phenylephrine Hydrochloride (PHCl) observed in some studies could be caused by changes in...
PURPOSE
We tested the hypothesis that changes in accommodation after instillation of Phenylephrine Hydrochloride (PHCl) observed in some studies could be caused by changes in optics.
METHODS
We performed two experiments to test the effects of PHCl on static and on dynamic accommodation in 8 and 6 subjects, respectively. Objective wavefront measurements were recorded of the static accommodation response to a stimulus at different distances or dynamic accommodation response to a sinusoidally moving stimulus (between 1 and 3 D of accommodative demand at 0.2Hz). The responses were characterized using two methods: one that takes into account the mydriatic optical effects on the accommodation produced by higher-order aberrations of the eye and another that takes into account only power changes paraxially due to the action of the ciliary muscle and regardless of the pupil size.
RESULTS
When mydriatic optical effects were taken into account, differences in responses before and after PHCl instillation were 0.51±0.53 D, and 0.12±0.15, for static and dynamic accommodation, respectively, and were statistically significant (p<0.039). When mydriatic optical effects were not taken into account, the differences in responses before and after PHCl instillation were -0.20±0.51 D, and -0.05±0.14, for static and dynamic accommodation, respectively, and were not statistically significant (p>0.313).
CONCLUSIONS
The mydriatic effect of the PHCl causes optical changes in the eye that can reduce the objective and subjective measurement of accommodation.
Topics: Accommodation, Ocular; Adult; Ciliary Body; Female; Humans; Male; Mydriatics; Phenylephrine
PubMed: 29602687
DOI: 10.1016/j.optom.2018.01.005 -
Experimental Physiology Dec 2023What is the central question of this study? What are the biggest challenges in performing in vitro studies on isolated human umbilical arteries? What is the main finding...
NEW FINDINGS
What is the central question of this study? What are the biggest challenges in performing in vitro studies on isolated human umbilical arteries? What is the main finding and its importance? The protocols presented in this study indicate some potential outcomes important for interpretation of the vascular responsivities of human umbilical arteries and could be useful for planning future in vitro studies with human umbilical arteries.
ABSTRACT
Human umbilical artery (HUA) preparations are of particular importance for in vitro studies on isolated blood vessels because their sampling is not risky for the patient, and they can provide the closest possible impression of changes related to the uteroplacental circulation during pre-eclampsia. Using organ bath techniques, useful experimental protocols are provided for measuring some pathophysiological phenomena in the vascular responses of HUAs. Several vasoconstrictors (serotonin, prostaglandin F and phenylephrine) and vasodilators (acetylcholine and minoxidil) were seleted for determination of their vasoactivity in HUAs. The role of L-type voltage-operated calcium channels and different types of potassium channels (K , BK and K ) were assessed, as was the impact of homocysteine. Serotonin was confirmed to be the most potent vasoconstrictor, while acetylcholine and phenylephrine caused variability in the relaxation and contraction response of HUA, respectively. The observed increase in serotonin-induced contraction and a decrease in minoxidil-induced relaxation in the presence of homocysteine suggested its procontractile effect on HUA preparations. Using selective blockers, it was determined that K and K channels participate in the minoxidil-induced relaxation, while L-type voltage-dependent Ca channels play an important role in the serotonin-induced contraction. The presented protocols reveal some of the methodological challenges related to HUA preparations and indicate potential outcomes in interpreting the vascular effects of the investigated substances, both in physiological conditions and in the homocysteine-induced pre-eclampsia model.
Topics: Pregnancy; Female; Humans; Umbilical Arteries; Serotonin; Acetylcholine; Minoxidil; Pre-Eclampsia; Vasodilation; Vasoconstrictor Agents; Phenylephrine; Homocysteine; Adenosine Triphosphate
PubMed: 37837634
DOI: 10.1113/EP091374 -
Anesthesia and Analgesia Dec 2022Early hypotension after severe traumatic brain injury (sTBI) is associated with increased mortality and poor long-term outcomes. Current guidelines suggest the use of...
BACKGROUND
Early hypotension after severe traumatic brain injury (sTBI) is associated with increased mortality and poor long-term outcomes. Current guidelines suggest the use of intravenous vasopressors, commonly norepinephrine and phenylephrine, to support blood pressure after TBI. However, guidelines do not specify vasopressor type, resulting in variation in clinical practice. We describe early vasopressor utilization patterns in critically ill patients with TBI and examine the association between utilization of norepinephrine, compared to phenylephrine, with hospital mortality after sTBI.
METHODS
We conducted a retrospective cohort study of US hospitals participating in the Premier Healthcare Database between 2009 and 2018. We examined adult patients (>17 years of age) with a primary diagnosis of sTBI who were treated in an intensive care unit (ICU) after injury. The primary exposure was vasopressor choice (phenylephrine versus norepinephrine) within the first 2 days of hospital admission. The primary outcome was in-hospital mortality. Secondary outcomes examined included hospital length of stay (LOS) and ICU LOS. We conducted a post hoc subgroup analysis in all patients with intracranial pressure (ICP) monitor placement. Regression analysis was used to assess differences in outcomes between patients exposed to phenylephrine versus norepinephrine, with propensity matching to address selection bias due to the nonrandom allocation of treatment groups.
RESULTS
From 2009 to 2018, 24,718 (37.1%) of 66,610 sTBI patients received vasopressors within the first 2 days of hospitalization. Among these patients, 60.6% (n = 14,991) received only phenylephrine, 10.8% (n = 2668) received only norepinephrine, 3.5% (n = 877) received other vasopressors, and 25.0% (n = 6182) received multiple vasopressors. In that time period, the use of all vasopressors after sTBI increased. A moderate degree of variation in vasopressor choice was explained at the individual hospital level (23.1%). In propensity-matched analysis, the use of norepinephrine compared to phenylephrine was associated with an increased risk of in-hospital mortality (OR, 1.65; CI, 1.46-1.86; P < .0001).
CONCLUSIONS
Early vasopressor utilization among critically ill patients with sTBI is common, increasing over the last decade, and varies across hospitals caring for TBI patients. Compared to phenylephrine, norepinephrine was associated with increased risk of in-hospital mortality in propensity-matched analysis. Given the wide variation in vasopressor utilization and possible differences in efficacy, our analysis suggests the need for randomized controlled trials to better inform vasopressor choice for patients with sTBI.
Topics: Adult; Humans; Critical Illness; Retrospective Studies; Vasoconstrictor Agents; Phenylephrine; Norepinephrine; Brain Injuries, Traumatic
PubMed: 35203085
DOI: 10.1213/ANE.0000000000005949 -
Alternative Therapies in Health and... Oct 2022To investigate the therapeutic effect of phenylephrine combined with goal-directed fluid therapy (GDFT) in elderly patients undergoing total hip arthroplasty. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To investigate the therapeutic effect of phenylephrine combined with goal-directed fluid therapy (GDFT) in elderly patients undergoing total hip arthroplasty.
METHODS
From June 2018 to May 2019, a total of 80 patients, age > 70 years, scheduled for total hip arthroplasty at Guangzhou Red Cross Hospital in China were consecutively included in this prospective randomized controlled trial. The patients were divided into 2 groups of 40 patients each by the random number table method. Patients in the control group were given GDFT alone, and patients in the experimental group were given phenylephrine combined with GDFT. The duration of surgery, blood loss, intraoperative urine output, and fluid input were analyzed. Heart rate (HR), mean arterial pressure (MAP), cardiac index (CI) and stroke volume variation (SVV) were compared in the 2 groups at different times: before surgery (T0), after induction (T1), before bone cement placement (T2), after bone cement placement (T3) and after surgery (T4). Lactate, oxygenation index and cerebral oxygen uptake rate were compared perioperatively. Meanwhile, the incidence of abdominal distension, nausea and vomiting, pulmonary infection and cognitive dysfunction within 7 days after surgery were compared.
RESULTS
The intraoperative fluid input in the experimental group was significantly lower than in the control group (P < .05). In T1 and T3, heart rate (HR) and stroke volume variability (SVV) in the control group were significantly higher than in the experimental group (P < .05), but mean arterial pressure (MAP) and cardiac index (CI) were significantly lower than in the experimental group (P < .05). The intraoperative lactic acid in the control group was significantly higher than in the experimental group (P < .05). In addition, we found that the intraoperative oxygenation index and the postsurgical oxygenation index in the control group decreased by 86.86% and 87.49%, respectively, compared with the preoperative values (P < .05). In addition, at T1 and T3, HR and SVV in the control group were significantly higher than T0 (P < .05), while MAP and CI were significantly lower than T0 (P < .05). In the experimental group, there was no significant difference in HR, SVV, MAP or CI at any time points compared with those of T0 (P < .05). The oxygenation index in the control group was lower than before surgery (P < .05). There was no significant difference in urine volume or brain oxygen uptake between the 2 groups (P < .05).
CONCLUSION
Phenylephrine combined with GDFT can be used in elderly patients undergoing hip arthroplasty to reduce fluid input and improve intraoperative hemodynamic stability, to reduce the occurrence of postoperative related complications.
Topics: Aged; Arthroplasty, Replacement, Hip; Bone Cements; Fluid Therapy; Goals; Humans; Lactic Acid; Oxygen; Phenylephrine; Postoperative Complications; Prospective Studies
PubMed: 35839108
DOI: No ID Found -
The Journal of Thoracic and... Jun 2023Cardioplegia and cardiopulmonary bypass dysregulate coronary vasomotor tone, which can be further affected by common comorbidities in patients undergoing cardiac...
OBJECTIVE
Cardioplegia and cardiopulmonary bypass dysregulate coronary vasomotor tone, which can be further affected by common comorbidities in patients undergoing cardiac surgery. This study investigates differences in coronary myogenic tone and vasomotor responses to phenylephrine before and after cardioplegia and cardiopulmonary bypass based on hypertension history.
METHODS
Coronary arterioles before and after cardioplegia and cardiopulmonary bypass were dissected from atrial tissue samples in patients with no hypertension, well-controlled hypertension, or uncontrolled hypertension, as determined by documented history of hypertension, antihypertensive agent use, and clinical blood pressure measurements averaged over 1 year. Myogenic tone in response to stepwise increases in intraluminal pressure was studied between pressure steps. Microvascular reactivity in response to phenylephrine was assessed via vessel myography. Protein expression was measured with immunoblotting.
RESULTS
Coronary myogenic tone was significantly increased in the uncontrolled hypertension group compared with the no hypertension and well-controlled hypertension groups before cardioplegia and cardiopulmonary bypass at higher intraluminal pressures, and after cardioplegia and cardiopulmonary bypass across all intraluminal pressures (P < .05). Contractile responses to phenylephrine were significantly enhanced in patients in the uncontrolled hypertension group compared with the well-controlled hypertension group before cardioplegia and cardiopulmonary bypass, and in the uncontrolled hypertension group compared with the no hypertension and well-controlled hyertension groups after cardioplegia and cardiopulmonary bypass (P < .05). There were no differences in myogenic tone or phenylephrine-induced reactivity between the no hypertension and well-controlled hypertension groups (P > .05). There was increased expression of phosphorylated protein kinase C alpha in the uncontrolled hypertension group after cardiopulmonary bypass compared with before cardiopulmonary bypass and increased phosphorylated extracellular signal-regulated kinase 1/2 in the uncontrolled hypertension compared with the no hypertension group after cardiopulmonary bypass (P < .05).
CONCLUSIONS
Uncontrolled hypertension is associated with increased coronary myogenic tone and vasoconstrictive response to phenylephrine that persists after cardioplegia and cardiopulmonary bypass.
Topics: Humans; Cardiopulmonary Bypass; Heart Arrest, Induced; Phenylephrine; Arterioles
PubMed: 36008180
DOI: 10.1016/j.jtcvs.2022.07.022 -
American Journal of Physiology.... Apr 2022Muscle sympathetic nerve activity (MSNA) increases during hyperinsulinemia, primarily attributed to central nervous system effects. Whether peripheral vasodilation...
Muscle sympathetic nerve activity (MSNA) increases during hyperinsulinemia, primarily attributed to central nervous system effects. Whether peripheral vasodilation induced by insulin further contributes to increased MSNA via arterial baroreflex-mediated mechanisms requires further investigation. Accordingly, we examined baroreflex modulation of the MSNA response to hyperinsulinemia. We hypothesized that rescuing peripheral resistance with coinfusion of the vasoconstrictor phenylephrine would attenuate the MSNA response to hyperinsulinemia. We further hypothesized that the insulin-mediated increase in MSNA would be recapitulated with another vasodilator (sodium nitroprusside, SNP). In 33 young healthy adults (28 M/5F), MSNA (microneurography) and arterial blood pressure (BP, Finometer/brachial catheter) were measured, and total peripheral resistance (TPR, ModelFlow) and baroreflex sensitivity were calculated at rest and during intravenous infusion of insulin ( = 20) or SNP ( = 13). A subset of participants receiving insulin ( = 7) was coinfused with phenylephrine. Insulin infusion decreased TPR ( = 0.01) and increased MSNA ( < 0.01), with no effect on arterial baroreflex sensitivity or BP ( > 0.05). Coinfusion with phenylephrine returned TPR and MSNA to baseline, with no effect on arterial baroreflex sensitivity ( > 0.05). Similar to insulin, SNP decreased TPR ( < 0.02) and increased MSNA ( < 0.01), with no effect on arterial baroreflex sensitivity ( > 0.12). Acute hyperinsulinemia shifts the baroreflex stimulus-response curve to higher MSNA without changing sensitivity, likely due to insulin's peripheral vasodilatory effects. Results show that peripheral vasodilation induced by insulin contributes to increased MSNA during hyperinsulinemia. We hypothesized that elevation in muscle sympathetic nervous system activity (MSNA) during hyperinsulinemia is mediated by its peripheral vasodilator effect on the arterial baroreflex. Using three separate protocols in humans, we observed increases in both MSNA and cardiac output during hyperinsulinemia, which we attributed to the baroreflex response to peripheral vasodilation induced by insulin. Results show that peripheral vasodilation induced by insulin contributes to increased MSNA during hyperinsulinemia.
Topics: Adult; Baroreflex; Blood Pressure; Heart Rate; Humans; Hyperinsulinism; Insulin; Muscle, Skeletal; Phenylephrine; Sympathetic Nervous System; Vasodilator Agents
PubMed: 35187960
DOI: 10.1152/ajpendo.00391.2021