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Survey of Ophthalmology 2022Intracameral phenylephrine is commonly used in ophthalmic surgery as an alternative or supplement to mydriatic eye drops; hence, the importance of an evidence-based... (Review)
Review
Intracameral phenylephrine is commonly used in ophthalmic surgery as an alternative or supplement to mydriatic eye drops; hence, the importance of an evidence-based understanding of its risk-benefit profile is vital. We performed a comprehensive search in the PubMed, Google Scholar, and Cochrane databases for published studies and case reports relating to the use of intracameral phenylephrine. Articles from 1958 to 2021 with the following keywords were used: "intracameral phenylephrine," "intracameral mydriatics," "phenylephrine," "pupil dilation," "complications." Intracameral phenylephrine was first used in 2003 as an alternative to topical mydriatics. Since then, it is being increasingly used with a variety of benefits, including rapid onset of mydriasis, and cost-effectiveness. There are various case reports, however, of ocular and systemic complications associated with intracameral phenylephrine such as generation of free radicals, toxic anterior segment syndrome, inconsistent pupillary dilation during surgery, and ventricular fibrillation. Alternatives to intracameral phenylephrine such as iris hooks, a Malyugin ring, intracameral epinephrine, and intracameral tropicamide were compared with intracameral phenylephrine. Intracameral phenylephrine appears to have a good safety profile.
Topics: Humans; Lidocaine; Mydriatics; Ophthalmic Solutions; Phacoemulsification; Phenylephrine; Pupil
PubMed: 35691387
DOI: 10.1016/j.survophthal.2022.06.002 -
European Journal of Anaesthesiology May 2017
Topics: Anesthesia, Spinal; Blood Pressure; Cardiac Output; Humans; Phenylephrine
PubMed: 28375979
DOI: 10.1097/EJA.0000000000000591 -
ELife Sep 2022Fibroblasts produce the majority of collagen in the heart and are thought to regulate extracellular matrix (ECM) turnover. Although fibrosis accompanies many cardiac...
Fibroblasts produce the majority of collagen in the heart and are thought to regulate extracellular matrix (ECM) turnover. Although fibrosis accompanies many cardiac pathologies and is generally deleterious, the role of fibroblasts in maintaining the basal ECM network and in fibrosis in vivo is poorly understood. We genetically ablated fibroblasts in mice to evaluate the impact on homeostasis of adult ECM and cardiac function after injury. Fibroblast-ablated mice demonstrated a substantive reduction in cardiac fibroblasts, but fibrillar collagen and the ECM proteome were not overtly altered when evaluated by quantitative mass spectrometry and N-terminomics. However, the distribution and quantity of collagen VI, microfibrillar collagen that forms an open network with the basement membrane, was reduced. In fibroblast-ablated mice, cardiac function was better preserved following angiotensin II/phenylephrine (AngII/PE)-induced fibrosis and myocardial infarction (MI). Analysis of cardiomyocyte function demonstrated altered sarcomere shortening and slowed calcium decline in both uninjured and AngII/PE-infused fibroblast-ablated mice. After MI, the residual resident fibroblasts responded to injury, albeit with reduced proliferation and numbers immediately after injury. These results indicate that the adult mouse heart tolerates a significant degree of fibroblast loss with a potentially beneficial impact on cardiac function after injury. The cardioprotective effect of controlled fibroblast reduction may have therapeutic value in heart disease.
Topics: Angiotensin II; Animals; Calcium; Collagen; Fibroblasts; Fibrosis; Mice; Myocardial Infarction; Myocardium; Phenylephrine; Proteome; Receptor, Platelet-Derived Growth Factor alpha
PubMed: 36149056
DOI: 10.7554/eLife.69854 -
Ophthalmic Plastic and Reconstructive... 2018To characterize the phenylephrine test in ptotic patients to help clinicians perform the test more efficiently.
PURPOSE
To characterize the phenylephrine test in ptotic patients to help clinicians perform the test more efficiently.
METHODS
Adults with involutional ptosis (n = 24, 30 eyes) were assessed with digital photographs for response to topical 2.5% phenylephrine drop instillation. Patient characteristics (age, gender, iris color, dermatochalasis, brow ptosis, and baseline marginal reflex distance-1 [MRD-1] height) were recorded. From the photographs, change in (MRD-1), presence of conjunctival blanching, pupillary dilation, and Hering effect were recorded at specified time intervals, 1 minute to 1 hour after drop placement. Correlations between patient characteristics and measured outcomes were evaluated using analysis of variance, Pearson coefficient, or chi-square tests.
RESULTS
The authors found that 73% of eyes had eyelid elevation with phenylephrine. Of these, 50% reached maximal eyelid elevation by 5 minutes, and 86% by 10 minutes after drop placement, but 14% did not reach maximal MRD-1 until 30 minutes. There is a negative correlation between the maximum MRD-1 and the baseline MRD-1 eyelid height (r = -0.5330, p < 0.01). There is no significant relationship between time to pupillary dilation with either time to max eyelid elevation or max eyelid elevation. No patient characteristic studied affected the likelihood of eyelid response to phenylephrine or presence of Hering effect.
CONCLUSIONS
Although most ptotic eyelids demonstrate a response to 2.5% phenylephrine within 10 minutes, there is a subset of patients that respond much later. More ptotic eyelids had greater eyelid elevation with phenylephrine. Pupillary dilation and conjunctival blanching are neither predictive of nor temporally associated with eyelid height elevation. The authors did not identify any patient factors (e.g., dermatochalasis, brow ptosis) that can predict the likelihood of response to phenylephrine.
Topics: Adult; Aged; Blepharoptosis; Eyelids; Female; Humans; Male; Middle Aged; Mydriatics; Phenylephrine
PubMed: 28353471
DOI: 10.1097/IOP.0000000000000903 -
Cell Death & Disease Jul 2023Pathological cardiac hypertrophy involves multiple regulators and several signal transduction pathways. Currently, the mechanisms of it are not well understood....
Pathological cardiac hypertrophy involves multiple regulators and several signal transduction pathways. Currently, the mechanisms of it are not well understood. Differentially expressed in FDCP 6 homolog (DEF6) was reported to participate in immunity, bone remodeling, and cancers. The effects of DEF6 on pathological cardiac hypertrophy, however, have not yet been fully characterized. We initially determined the expression profile of DEF6 and found that DEF6 was upregulated in hypertrophic hearts and cardiomyocytes. Our in vivo results revealed that DEF6 deficiency in mice alleviated transverse aortic constriction (TAC)-induced cardiac hypertrophy, fibrosis, dilation and dysfunction of left ventricle. Conversely, cardiomyocyte-specific DEF6-overexpression aggravated the hypertrophic phenotype in mice under chronic pressure overload. Similar to the animal experiments, the in vitro data showed that adenovirus-mediated knockdown of DEF6 remarkably inhibited phenylephrine (PE)-induced cardiomyocyte hypertrophy, whereas DEF6 overexpression exerted the opposite effects. Mechanistically, exploration of the signal pathways showed that the mitogen-activated extracellular signal-regulated kinase 1/2 (MEK1/2)-extracellular signal-regulated kinase 1/2 (ERK1/2) cascade might be involved in the prohypertrophic effect of DEF6. Coimmunoprecipitation and GST (glutathione S-transferase) pulldown analyses demonstrated that DEF6 can directly interact with small GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1), and the Rac1 activity assay revealed that the activity of Rac1 is altered with DEF6 expression in TAC-cardiac hypertrophy and PE-triggered cardiomyocyte hypertrophy. In the end, western blot and rescue experiments using Rac1 inhibitor NSC23766 and the constitutively active mutant Rac1(G12V) verified the requirement of Rac1 and MEK1/2-ERK1/2 activation for DEF6-mediated pathological cardiac hypertrophy. Our study substantiates that DEF6 acts as a deleterious regulator of cardiac hypertrophy by activating the Rac1 and MEK1/2-ERK1/2 signaling pathways, and suggests that DEF6 may be a potential treatment target for heart failure.
Topics: Mice; Animals; Mitogen-Activated Protein Kinase 3; Cardiomegaly; Heart Failure; Signal Transduction; Myocytes, Cardiac; Phenylephrine; Mice, Inbred C57BL; Disease Models, Animal
PubMed: 37524688
DOI: 10.1038/s41419-023-05948-0 -
Acta Anaesthesiologica Scandinavica Aug 2023Phenylephrine increases systemic- and pulmonary resistances and therefore may increase blood pressures at the expense of blood flow. Cardio-pulmonary bypass alters... (Clinical Trial)
Clinical Trial
BACKGROUND
Phenylephrine increases systemic- and pulmonary resistances and therefore may increase blood pressures at the expense of blood flow. Cardio-pulmonary bypass alters vasoreactivity and many patients exhibit chronotropic insufficiency after cardiac surgery. We aimed to describe the haemodynamic effects of phenylephrine infusion after cardiac surgery.
METHODS
Patients in steady state after low-risk cardiac surgery received incremental infusion rates of phenylephrine up to 1.0 μg/kg/min with the aim of increasing systemic mean arterial blood pressure 20 mmHg. Invasive haemodynamic parameters, including pulmonary wedge pressures, were captured along with echocardiographic measures of biventricular function before, during phenylephrine infusion at target systemic blood pressure, and 20 min after phenylephrine discontinuation.
RESULTS
Thirty patients were included. Phenylephrine increased mean arterial pressure increased from 78 (±9) mmHg to 98 (±10) mmHg with phenylephrine infusion. Also, pulmonary blood pressure as well as systemic- and pulmonary resistances increased. The ratio between systemic- and pulmonary artery resistances did not change statistically significantly (p = .59). Median cardiac output was 4.35 (interquartile range [IQR] 3.6-5.4) L/min at baseline and increased significantly with phenylephrine infusion (median Δcardiac output was 0.25 [IQR 0.1-0.6] L/min) (p = .012). Pulmonary artery wedge pressure increased from 10.2 (±3.0) mmHg to 11.9 (±3.4) mmHg (p < .001). This was accompanied by significant increases in central venous pressure. Phenylephrine infusion increased left ventricular end-diastolic volume from 105 (±46) mL to 119 (±44) mL (p < .001). All results of phenylephrine infusion were reversed with discontinuation.
CONCLUSION
In haemodynamically stable patients after cardiac surgery, phenylephrine increased PVR and SVR, but did not change the PVR/SVR ratio. Phenylephrine increased biventricular filling pressures and left ventricular end-diastolic area. Consequently, CO increased as ejection fraction was maintained. These findings do not discourage the use of phenylephrine after low-risk cardiac surgery.
REGISTRATION
clinicaltrial.gov (identifier NCT04419662).
Topics: Humans; Blood Pressure; Cardiac Output; Cardiac Surgical Procedures; Hemodynamics; Phenylephrine; Pulmonary Wedge Pressure
PubMed: 37186094
DOI: 10.1111/aas.14256 -
Anaesthesia Jan 2024We conducted a systematic review of the literature reporting phenylephrine-induced changes in blood pressure, cardiac output, cerebral blood flow and cerebral tissue... (Review)
Review
We conducted a systematic review of the literature reporting phenylephrine-induced changes in blood pressure, cardiac output, cerebral blood flow and cerebral tissue oxygen saturation as measured by near-infrared spectroscopy in humans. We used the proportion change of the group mean values reported by the original studies in our analysis. Phenylephrine elevates blood pressure whilst concurrently inducing a reduction in cardiac output. Furthermore, despite increasing cerebral blood flow, it decreases cerebral tissue oxygen saturation. The extent of phenylephrine's influence on cardiac output (r = -0.54 and p = 0.09 in awake humans; r = -0.55 and p = 0.007 in anaesthetised humans), cerebral blood flow (r = 0.65 and p = 0.002 in awake humans; r = 0.80 and p = 0.003 in anaesthetised humans) and cerebral tissue oxygen saturation (r = -0.72 and p = 0.03 in awake humans; r = -0.24 and p = 0.48 in anaesthetised humans) appears closely linked to the magnitude of phenylephrine-induced blood pressure changes. When comparing the effects of phenylephrine in awake and anaesthetised humans, we found no evidence of a significant difference in cardiac output, cerebral blood flow or cerebral tissue oxygen saturation. There was also no evidence of a significant difference in effect on systemic and cerebral circulations whether phenylephrine was given by bolus or infusion. We explore the underlying mechanisms driving the phenylephrine-induced cardiac output reduction, cerebral blood flow increase and cerebral tissue oxygen saturation decrease. Individualised treatment approaches, close monitoring and consideration of potential risks and benefits remain vital to the safe and effective use of phenylephrine in acute care.
Topics: Humans; Phenylephrine; Vasoconstrictor Agents; Oxygen; Blood Pressure; Cerebrovascular Circulation
PubMed: 37948131
DOI: 10.1111/anae.16172 -
Journal of Ocular Pharmacology and... Dec 2017To compare the effectiveness of intracameral phenylephrine and topical mydriatics in achieving mydriasis and protecting against complications during phacoemulsification. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
To compare the effectiveness of intracameral phenylephrine and topical mydriatics in achieving mydriasis and protecting against complications during phacoemulsification.
METHODS
A systematic search of the literature comparing the mydriatic effect and surgical safety profile of intracameral phenylephrine and topical mydriatics in phacoemulsification was conducted in the Medline, Embase, Lilacs, Web of Science, Cochrane, ClinicalTrials.gov , and Teseo databases. The search targeted clinical trials, cohort studies, and case-control studies published between April 20, 2003 and August 14, 2016. Mydriatic effect was assessed by difference in means in pupil of all the patients in the studies [mean difference (MD)] and intraoperative complications were assessed by using inverse-variance weighted odds ratios (ORs), with adjustment for dose. A meta-regression analysis was also conducted, with adjustment for dose, use of epinephrine, tamsulosin use, and type of surgery and type of intraocular lens.
RESULTS
We found 7 articles about mydriatic effect and another 7 about complications. Intracameral phenylephrine achieved a similar mydriatic effect to topical mydriatics, with a difference of less than 10% (MD -0.74 mm, 95% CI: -1.67 to 0.18, I = 95.8%, P < 0.0001). The pooled OR for complications was OR 0.50, 95% CI: 0.19-1.31, I = 0.0%, P = 0.670, and posterior capsular rupture was the most common complication in the different studies analyzed.
CONCLUSION
Intracameral phenylephrine achieves a similar mydriatic effect to topical mydriatics (difference <15%) and is associated with a not-significant effect on reducing the odds of intraoperative complications.
Topics: Animals; Anterior Chamber; Humans; Intraoperative Complications; Mydriatics; Phacoemulsification; Phenylephrine; Pupil
PubMed: 29099656
DOI: 10.1089/jop.2017.0084 -
Paediatric Anaesthesia Jul 2017Intranasal phenylephrine, an alpha-1 adrenergic agonist, causes vasoconstriction of the nasal mucosa and is used to reduce bleeding associated with nasotracheal... (Randomized Controlled Trial)
Randomized Controlled Trial
INTRODUCTION
Intranasal phenylephrine, an alpha-1 adrenergic agonist, causes vasoconstriction of the nasal mucosa and is used to reduce bleeding associated with nasotracheal intubation or endoscopic sinus surgery. The purpose of this study was to describe the hemodynamic effects associated with plasma phenylephrine concentrations following topical intranasal administration of 0.25% and 0.5% phenylephrine in children.
METHODS
After Institutional Review Board and parental approval, 77 children between the ages of 2 and 12 years were studied in a prospective, double-blind manner and randomized into three groups. Group 1 received intranasal saline, while groups 2 and 3 received 0.1 mL/kg of 0.25% or 0.5% phenylephrine, respectively. All received the same anesthetic of halothane, N O, O , and vecuronium. After inhalation induction, endtidal halothane and PaCO were maintained at 1.5% and 35 mm Hg, respectively. Heart rate and rhythm, systolic, diastolic, and mean, noninvasive arterial blood pressures were recorded and venous blood was obtained for measurement of plasma phenylephrine concentration by high-performance liquid chromatography at baseline and at 2, 5, 10, and 20 minutes following intranasal spray application of the study drug. Nasotracheal intubation was performed immediately following the 5-minute measurements, and the presence of bleeding was assessed. Hemodynamic data were compared by analysis of variance for repeated measures. Bleeding and arrhythmia incidence among groups were analyzed using chi-squared tests. Phenylephrine levels were correlated with hemodynamic values via regression analysis.
RESULTS
Fifty-two patients received intranasal phenylephrine. Increases in blood pressure correlated with increasing plasma phenylephrine concentration. Systolic blood pressure increased 8%, and mean blood pressure increased 14%, which were statistically significant but clinically insignificant. Heart rate did not change, and the incidence of arrhythmia was low and similar among groups. Bleeding following nasotracheal intubation was less frequent in Group 3 (11/27 subjects) than in Group 1 (17/25). Peak plasma phenylephrine concentrations were observed by 14±7 minutes following intranasal administration, and were highly variable among individuals (37.8±39.7 and 49.6±93.9 ng/mL [mean±SD] in Groups 2 and 3).
DISCUSSION
Administration of intranasal phenylephrine, 0.25% and 0.50%, results in rapid but highly variable systemic absorption that is associated with mild increases of blood pressure that are clinically insignificant. Bleeding associated with nasotracheal intubation was less following administration of 0.5% intranasal phenylephrine than following intranasal saline.
Topics: Administration, Intranasal; Anesthesia, General; Arrhythmias, Cardiac; Blood Pressure; Child; Child, Preschool; Chromatography, High Pressure Liquid; Double-Blind Method; Female; Heart Rate; Hemodynamics; Humans; Infant; Male; Nasal Sprays; Phenylephrine; Prospective Studies; Vasoconstrictor Agents
PubMed: 28504321
DOI: 10.1111/pan.13168 -
Current Opinion in Anaesthesiology Jun 2017Hypotension remains one of the most researched subjects in obstetric anaesthesia. The purpose of this study is to review the most recent published articles on the use of... (Review)
Review
PURPOSE OF REVIEW
Hypotension remains one of the most researched subjects in obstetric anaesthesia. The purpose of this study is to review the most recent published articles on the use of vasopressors during spinal anaesthesia for caesarean section.
RECENT FINDINGS
Despite continued research indicating advantages of phenylephrine over ephedrine, practitioners in some countries continue to favour ephedrine. Recent research has continued to compare the two drugs with some work emerging on high-risk patients. Concern about reflexive bradycardia during phenylephrine use has led to consideration of alternatives. Norepinephrine which has mild β-adrenergic activity has been shown to have equivalent pressor activity but with less depressant effect on heart rate and cardiac output versus phenylephrine. Research continues to focus on methods of vasopressor administration. Prophylactic infusions of phenylephrine have been shown to be effective and may require less physician intervention compared with intermittent boluses. Automated computer-controlled systems have been further investigated using multiple agents and continuous noninvasive blood pressure monitoring.
SUMMARY
Evidence continues to support phenylephrine as the first-line vasopressor in obstetrics. However, recent research is emerging to suggest that low-dose norepinephrine may be a better alternative. Prophylactic infusions are effective and automated systems have potential for the future.
Topics: Adult; Anesthesia, Obstetrical; Anesthesia, Spinal; Cardiac Output; Cesarean Section; Dose-Response Relationship, Drug; Drug Dosage Calculations; Drug Therapy, Computer-Assisted; Ephedrine; Female; Heart Rate; Humans; Hypotension; Intraoperative Complications; Metaraminol; Methoxamine; Norepinephrine; Phenylephrine; Pregnancy; Pregnancy, High-Risk; Vasoconstrictor Agents
PubMed: 28277383
DOI: 10.1097/ACO.0000000000000453