Axial length and pharmacologic pupillary dilation in highly myopic patients

PURPOSE

To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length.

METHODS

Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30 min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation.

RESULTS

Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08 mm, 95% CI: 6.97 to 7.19 mm) than controls (6.23 mm, 95% CI: 5.94 to 6.52 mm) after 30 min of dilation (P < .0005). Fully dilated pupil size at 30 min was significantly correlated with both refractive error (r =  - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter.

CONCLUSIONS

Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

Spinal decompression surgery may alleviate vasopressor-induced spinal hemorrhage and extravasation during acute cervical spinal cord injury in rats

BACKGROUND

Cervical spinal injury often disrupts the supraspinal vasomotor pathways projecting to the thoracic sympathetic preganglionic neurons, leading to cardiovascular dysfunction. The current guideline is to maintain the mean arterial blood pressure at 85 to 90 mmHg using a vasopressor during the first week of the injury. Some studies have demonstrated that this treatment might be beneficial to alleviate secondary injury and improve neurological outcomes; however, elevation of blood pressure may exacerbate spinal hemorrhage, extravasation, and edema, exacerbating the initial injury.

PURPOSE

The present study was designed to (1) examine whether vasopressor administration exacerbates spinal hemorrhage and extravasation; (2) evaluate whether spinal decompression surgery relieves vasopressor-induced spinal hemorrhage and extravasation.

STUDY DESIGN

In vivo animal study.

METHODS

Animals received a saline solution or a vasopressor (phenylephrine hydrochloride, 500 or 1000 μg/kg, 7 mL/kg/h) after mid-cervical contusion with or without spinal decompression (ie, incision of the dura and arachnoid mater). Spinal cord hemorrhage and extravasation were examined by expression of Evans blue within the spinal cord section.

RESULTS

The results demonstrated that cervical spinal contusion significantly reduced the mean arterial blood pressure and induced spinal hemorrhage and extravasation. Phenylephrine infusion significantly elevated the mean arterial blood pressure to the preinjury level within 15 to 60 minutes postcontusion; however, spinal hemorrhage and extravasation were more extensive in animals that received phenylephrine than in those that received saline. Notably, spinal decompression mitigated spinal hemorrhage and extravasation in contused rats who received phenylephrine.

CONCLUSIONS

These data indicate that, although phenylephrine can prevent hypotension after cervical spinal injury, it also causes excess spinal hemorrhage and extravasation.

CLINICAL SIGNIFICANCE

Spinal decompressive surgery seemed to minimize the side effect of phenylephrine as vasopressor treatment during acute spinal cord injury.

Randomized Double-Blinded Comparison of Intermittent Boluses Phenylephrine and Norepinephrine for the Treatment of Postspinal Hypotension in Patients with Severe Pre-Eclampsia During Cesarean Section

Background

Norepinephrine has fewer negative effects on heart rate (HR) and cardiac output (CO) for treating postspinal hypotension (PSH) compared with phenylephrine during cesarean section. However, it remains unclear whether fetuses from patients with severe pre-eclampsia could benefit from the superiority of CO. The objective of this study was to compare the safety and efficacy of intermittent intravenous boluses of phenylephrine and norepinephrine used in equipotent doses for treating postspinal hypotension in patients with severe pre-eclampsia during cesarean section.

Methods

A total of 80 patients with severe pre-eclampsia who developed PSH predelivery during cesarean section were included. Eligible patients were randomized at a 1:1 ratio to receive either phenylephrine or norepinephrine for treating PSH. The primary outcome was umbilical arterial pH. Secondary outcomes included other umbilical cord blood gas values, Apgar scores at 1 and 5 min, changes in hemodynamic parameters including CO, mean arterial pressure (MAP), HR, stroke volume (SV), and systemic vascular resistance (SVR), the number of vasopressor boluses required, and the incidence of bradycardia, hypertension, nausea, vomiting, and dizziness.

Results

No significant difference was observed in umbilical arterial pH between the phenylephrine and norepinephrine groups (7.303±0.38 vs 7.303±0.44, respectively; P=0.978). Compared with the phenylephrine group, the overall CO (P=0.009) and HR (P=0.015) were greater in the norepinephrine group. The median [IQR] total number of vasopressor boluses required was comparable between the two groups (2 [1 to 3] and 2 [1 to 3], respectively; P=0.942). No significant difference was found in Apgar scores or the incidence of maternal complications between groups.

Conclusion

A 60 µg bolus of phenylephrine and a 4.5 µg bolus of norepinephrine showed similar neonatal outcomes assessed by umbilical arterial pH and were equally effective when treating PSH during cesarean section in patients with severe pre-eclampsia. Norepinephrine provided a higher maternal CO and a lower incidence of bradycardia.

A new algorithm for the transconjunctival correction of moderate to severe upper eyelid ptosis in adults

A posterior approach is recommended for the correction of mild to moderate upper eyelid ptosis in adults. The aim of this study is to propose a new algorithm that helps to predict outcomes in the transconjunctival correction of moderate to severe blepharoptosis. This study included adult patients with moderate to severe upper eyelid ptosis treated between 2019 and 2021. Patients meeting inclusion criteria underwent ptosis correction through a posterior approach using an algorithm: 4 mm Mueller's muscle transconjunctival resection to correct 1 mm ptosis (depending on a test with 10% phenylephrine: 3-12 mm) ± tarsal plate resection: 1 mm for every 1 mm of residual ptosis after phenylephrine test, but leaving a minimum of 4 mm upper tarsus intact. Outcomes were ovserved within at least 6-months. Outcomes were assessed based on pre- and postoperative MRD1 changes, inter-eyelid height symmetry, cosmetic effect, and complications. Outcomes of 118 procedures in 81 patients (average age 69, range: 47-87) were analyzed. MRD1 changes were statistically significant, from 0.2 ± 1.6 mm before to 4.1 ± 1 mm after surgery. The function of the levator palpebrae superioris muscle was 10.2 ± 3.4 (range 5-17) mm. Upper eyelid lifted by an average of 1.8 ± 0.7 (range 0-3) mm after the instillation of 10% phenylephrine eyedrops. An average of 8.5 ± 0.8 (range 8-10) mm of conjunctiva and Mueller's muscle and 2.2 ± 0.9 (range 1-5) mm of the tarsal plate were resected during the procedure. Inter-eyelid height symmetry within 1 mm was achieved in 95% of outcomes. The algorithm introduced in this study appears to be useful to achieve repeatable satisfactory outcomes in the transconjunctival correction of moderate to severe upper eyelid ptosis in adults with at least "fair" levator function.

Multi-walled carbon nanotubes/carbon black/rPLA for high-performance conductive additive manufacturing filament and the simultaneous detection of acetaminophen and phenylephrine

The combination of multi-walled carbon nanotubes (MWCNT) and carbon black (CB) is presented to produce a high-performance electrically conductive recycled additive manufacturing filament. The filament and subsequent additively manufactured electrodes were characterised by TGA, XPS, Raman, and SEM and showed excellent low-temperature flexibility. The MWCNT/CB filament exhibited an improved electrochemical performance compared to an identical in-house produced bespoke filament using only CB. A heterogeneous electrochemical rate constant, [Formula: see text] of 1.71 (± 0.19) × 10-3 cm s-1 was obtained, showing an almost six times improvement over the commonly used commercial conductive CB/PLA. The filament was successfully tested for the simultaneous determination of acetaminophen and phenylephrine, producing linear ranges of 5-60 and 5-200 μM, sensitivities of 0.05 μA μM-1 and 0.14 μA μM-1, and limits of detection of 0.04 μM and 0.38 μM, respectively. A print-at-home device is presented where a removable lid comprised of rPLA can be placed onto a drinking vessel and the working, counter, and reference components made from our bespoke MWCNT/CB filament. The print-at-home device was successfully used to determine both compounds within real pharmaceutical products, with recoveries between 87 and 120% over a range of three real samples. This work paves the way for fabricating new highly conductive filaments using a combination of carbon materials with different morphologies and physicochemical properties and their application to produce additively manufactured electrodes with greatly improved electrochemical performance.

Function of Presynaptic Inhibitory Cannabinoid CB1 Receptors in Spontaneously Hypertensive Rats and Its Modification by Enhanced Endocannabinoid Tone

We studied whether the function of presynaptic inhibitory cannabinoid CB1 receptors on the sympathetic nerve fibres innervating resistance vessels is increased in spontaneously hypertensive rats (SHR) like in deoxycorticosterone (DOCA)-salt hypertension. An increase in diastolic blood pressure (DBP) was induced by electrical stimulation of the preganglionic sympathetic neurons or by phenylephrine injection in pithed SHR and normotensive Wistar-Kyoto rats (WKY). The electrically (but not the phenylephrine) induced increase in DBP was inhibited by the cannabinoid receptor agonist CP55940, similarly in both groups, and by the endocannabinoid reuptake inhibitor AM404 in SHR only. The effect of CP55940 was abolished/reduced by the CB1 receptor antagonist AM251 (in both groups) and in WKY by endocannabinoid degradation blockade, i.e., the monoacylglycerol lipase (MAGL) inhibitor MJN110 and the dual fatty acid amide hydrolase (FAAH)/MAGL inhibitor JZL195 but not the FAAH inhibitor URB597. MJN110 and JZL195 tended to enhance the effect of CP55940 in SHR. In conclusion, the function of presynaptic inhibitory CB1 receptors depends on the hypertension model. Although no differences occurred between SHR and WKY under basal experimental conditions, the CB1 receptor function was better preserved in SHR when the endocannabinoid tone was increased by the inhibition of MAGL or the endocannabinoid transporter.

Case Report: Priapism Following an Anterior Lumbar Interbody Fusion

Priapism is a disorder where the penis without sexual stimulation maintains a prolonged rigid erection lasting 4 or more hours. There are two classifications of priapism, ischemic (low flow) or nonischemic high flow, and each have specific etiologies, diagnostic criteria, and management. This presented case study involved a 58-year-old male who experienced an ischemic priapism more than 24 hours after an anterior lumbar interbody fusion (ALIF). A flaccid penis was achieved after the patient received two 400 µg of phenylephrine HCL into the corpora cavernosum. Review of the literature suggests anesthetic medications given during the surgical procedure may have caused the priapism. Lessons that can be learned from this case study highlight that even though the nurse may not expect to see a priapism after an ALIF, the nurse must always be diligent and not become complacent with unexpected findings or assessments that may cause irreparable harm to the patient.

Optimization of resting tension for wire myography in male rat pulmonary arteries

Wire myography to test vasomotor functions of blood vessels ex-vivo are well-established for the systemic circulation, however, there is no consensus on protocols for pulmonary arteries. We created a standardized wire myography protocol for healthy rat PAs and validated this in a pulmonary hypertension (PH) model. Vessels stretched to higher initial tensions (5.0, 7.5 and 10.0 mN) exhibited a uniform response to phenylephrine, a larger dynamic range, and lower EC50 values. The endothelium-mediated relaxation showed that moderate tensions (7.5 and 10.0 mN) produced robust responses with higher maximum relaxation and lower EC50 values. For endothelium independent responses, the higher initial tension groups had lower and more consistent EC50 values than the lower initial tension groups. Pulmonary arteries from rats with PH were more responsive to vasoactive drugs when subjected to a higher initial tension. Notably, vessels in the PH group subjected to 15.0 mN exhibited high dynamic ranges in contractile and relaxation responses without tearing. Lastly, we observed attenuated cholinergic responses in these vessels-consistent with endothelial dysfunction in PH. Therefore, a moderate initial tension of 7.5-10.0 mN is optimal for healthy rat pulmonary arteries and a higher initial tension of 15.0 mN is optimal for pulmonary arteries from animals with PH.

YB-1 Is a Novel Target for the Inhibition of α-Adrenergic-Induced Hypertrophy

Cardiac hypertrophy resulting from sympathetic nervous system activation triggers the development of heart failure. The transcription factor Y-box binding protein 1 (YB-1) can interact with transcription factors involved in cardiac hypertrophy and may thereby interfere with the hypertrophy growth process. Therefore, the question arises as to whether YB-1 influences cardiomyocyte hypertrophy and might thereby influence the development of heart failure. YB-1 expression is downregulated in human heart biopsies of patients with ischemic cardiomyopathy (n = 8), leading to heart failure. To study the impact of reduced YB-1 in cardiac cells, we performed small interfering RNA (siRNA) experiments in H9C2 cells as well as in adult cardiomyocytes (CMs) of rats. The specificity of YB-1 siRNA was analyzed by a miRNA-like off-target prediction assay identifying potential genes. Testing three high-scoring genes by transfecting cardiac cells with YB-1 siRNA did not result in downregulation of these genes in contrast to YB-1, whose downregulation increased hypertrophic growth. Hypertrophic growth was mediated by PI3K under PE stimulation, as well by downregulation with YB-1 siRNA. On the other hand, overexpression of YB-1 in CMs, caused by infection with an adenovirus encoding YB-1 (AdYB-1), prevented hypertrophic growth under α-adrenergic stimulation with phenylephrine (PE), but not under stimulation with growth differentiation factor 15 (GDF15; n = 10-16). An adenovirus encoding the green fluorescent protein (AdGFP) served as the control. YB-1 overexpression enhanced the mRNA expression of the Gq inhibitor regulator of G-protein signaling 2 (RGS2) under PE stimulation (n = 6), potentially explaining its inhibitory effect on PE-induced hypertrophic growth. This study shows that YB-1 protects cardiomyocytes against PE-induced hypertrophic growth. Like in human end-stage heart failure, YB-1 downregulation may cause the heart to lose its protection against hypertrophic stimuli and progress to heart failure. Therefore, the transcription factor YB-1 is a pivotal signaling molecule, providing perspectives for therapeutic approaches.

Resolving phenylephrine HCl and guaifenesin enantiomers on cellulose-based chiral stationary phases: Separation of four enantiomers on 50-mm column

Chiral high performance liquid chromatographic technique usually employs polysaccharide-based stationary phases in a normal phase mode. This frequently generates large waste of organic solvents. Using shorter columns of 50 mm length as well as a mobile phase with a high water percentage are common approaches for greening this analytical technique. In this context, a new chiral chromatographic technique was developed for simultaneous enantio-separation of phenylephrine HCl and guaifenesin racemates. Four 50 mm cellulose-based columns were experimented to separate the four enantiomers in a reversed phase mode. A face centered design was then employed to optimize the mobile phase acetonitrile% and flow rate on Lux Cellulose-1 (50 × 4.6 mm, 5 μm). The simultaneous resolution of the cited drugs enantiomers was achieved using acetonitrile-water (30:70, by volume), with a flow rate of 0.5 ml min-1 . These optimized chromatographic conditions separate the enantiomers in 7 min running time, generating about 1.0 ml acetonitrile per run. The proposed method was favorably compared with other reported chiral ones in terms of waste volume generated and analysis time required.

Augmented sympathoexcitation slows postexercise heart rate recovery

Slow heart rate recovery following exercise may be influenced by persistent sympathoexcitation. This study examined 1) the effect of muscle metaboreflex activation (MMA) on heart rate recovery following dynamic exercise; and 2) whether the effect of MMA on heart rate recovery is reversible by reducing sympathoexcitation [baroreflex activation via phenylephrine (PE)] in canines. Twenty-two young adults completed control and MMA protocols during cycle ergometry at 110% ventilatory threshold with 5 min recovery. Heart rate recovery kinetics [tau (τ), amplitude, end-exercise, and end-recovery heart rate] and root mean square of successive differences (RMSSD) were measured. Five chronically instrumented canines completed control, MMA (50%-60% imposed reduction in hindlimb blood flow), and MMA with end-exercise PE infusion (MMA + PE) protocols during moderate exercise (6.4 km·h-1) and 3 min recovery. Heart rate recovery kinetics and MAP were measured. MAP increased during MMA versus control in canines (P < 0.001). Heart rate recovery τ was slower during MMA versus control in humans (17% slower; P = 0.011) and canines (150% slower; P = 0.002). Heart rate recovery τ was faster during MMA + PE versus MMA (40% faster; P = 0.034) and was similar to control in canines (P = 0.426). Amplitude, end-exercise, and end-recovery heart rate were similar between conditions in humans (all P ≥ 0.122) and in canines (all P ≥ 0.084). MMA decreased RMSSD in early recovery (P = 0.004). MMA-induced sympathoexcitation slows heart rate recovery and this effect is markedly attenuated with PE. Therefore, elevated sympathoexcitation via MMA impairs heart rate recovery and inhibition of this stimulus normalizes, in part, heart rate recovery.NEW & NOTEWORTHY Augmented sympathoexcitation, via muscle metaboreflex activation, functionally slows heart rate recovery in both young healthy adults and chronically instrumented canines. Furthermore, elevated sympathoexcitation corresponded with lower parasympathetic activity, as assessed by heart rate variability, during the first 3 min of recovery. Finally, sympathoinhibition, via phenylephrine infusion, normalizes heart rate recovery during muscle metaboreflex activation.

Are Potential Differences Influenced by Phenylephrine or Dobutamine?

OBJECTIVES

To investigate the agreement between continuous noninvasive blood pressure measurement with the ClearSight system (cNIBP-CS) and standard intermittent noninvasive blood pressure measurement (iNIBP) in patients with peripheral arterial disease (PAD). Additionally, the influence of vasoactive medication on potential measurement differences was assessed.

DESIGN

A secondary analysis of a randomized controlled trial.

SETTING

At a university hospital.

PARTICIPANTS

Thirty-four patients with PAD undergoing percutaneous transluminal angioplasty of the lower limbs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Continuous noninvasive blood pressures were measured with the "ClearSight" system and compared to standard iNIBPs. Bland-Altman analysis revealed a mean bias of 13 mmHg (±15) between cNIBP-CS and iNIBP, with 95% limits of agreement (LOA) ranging from -17 to 42 mmHg. When comparing both medication groups, a similar mean bias was found for phenylephrine and dobutamine (12 mmHg [±13] and 13 mmHg [±13], respectively).

CONCLUSION

In this study, in patients with PAD, cNIBP-CS showed an underestimation of blood pressure compared to iNIBP in phenylephrine- and dobutamine-treated patients. Compared to previous studies, a larger bias and wider 95% LOA were found.

Isometric myography is a feasible method to identify and quantify endothelial dysfunction in dogs with myxomatous mitral valve disease

OBJECTIVE

To assess the feasibility of isometric myography in pet dogs with myxomatous mitral valve disease (MMVD) to determine its use in quantifying endothelial dysfunction.

ANIMALS

9 dogs euthanized for medical reasons.

METHODS

Femoral, renal, and mesenteric arteries were collected postmortem and stored in physiological saline solution at 4 °C for myography. Mitral valves were scored for myxomatous degeneration (grades 1 to 4). Sections of arteries were mounted in wells, immersed in physiological saline solution perfused with 95% O2 and 5% CO2 at 37 °C, and stretched to an internal circumference (IC) that generated the maximal difference between active and passive wall tension (IC1). Normalization factors were calculated by dividing the IC1 by the IC at which the passive wall tension was 100 mm Hg (IC100). Vasoconstriction to phenylephrine and vasodilation to acetylcholine (endothelial dependent) and sodium nitroprusside (endothelial independent) were assessed by cumulative dose-response curves.

RESULTS

Median MMVD grade was 3. Mean values of normalization factors were 1.00 ± 0.14 (renal, n = 15), 1.00 ± 0.10 (femoral, 8), and 1.05 ± 0.12 (mesenteric, 6). Responses to phenylephrine were similar between dogs (P = .14). Reduced responses to acetylcholine compared with sodium nitroprusside were identified in 15 arteries, suggesting endothelial dysfunction.

CLINICAL RELEVANCE

Isometric myography of arteries from pet dogs is feasible and can identify loss of endothelial-dependent relaxation in dogs with MMVD postmortem. Its use in further research can lead to a better understanding of the pathophysiology mechanisms of this disease.

Near-Infrared Spectroscopy Monitoring to Detect Changes in Cerebral and Renal Perfusion During Hypovolemic Shock, Volume Resuscitation, and Vasoconstriction

INTRODUCTION

Rapidly changing hemodynamic conditions, such as uncontrolled hemorrhage and the resulting hypovolemic shock, are a common contributor to active duty military deaths. These conditions can cause cerebral desaturation, and outcomes may improve when regional cerebral oxygen saturation (CrSO2) is monitored using near-infrared spectroscopy (NIRS) and desaturation episodes are recognized and reversed. The purpose of this porcine study was to investigate the ability of NIRS monitoring to detect changes in regional cerebral and regional renal perfusion during hypovolemia, resuscitation by volume infusion, and vasoconstriction.

MATERIALS AND METHODS

Hemorrhagic shock was induced by removing blood through a central venous catheter until mean arterial pressure (MAP) was <40 mmHg. Each blood removal step was followed by a 10-minute stabilization period, during which cardiac output, blood pressure, central venous pressure, blood oxygen saturation, and CrSO2 and regional renal oxygen saturation (RrSO2) were measured. Shock was reversed using blood infusion and vasoconstriction separately until MAP returned to normal. Statistical comparisons between groups were performed using the paired t-test or the Wilcoxon signed-rank test.

RESULTS

Using volume resuscitation, both CrSO2 and RrSO2 returned to normal levels after hypovolemia. Blood pressure management with phenylephrine returned CrSO2 levels to normal, but RrSO2 levels remained significantly lower compared to the pre-hemorrhage values (P < .0001). Comparison of the percent CrSO2 as a function of MAP showed that CrSO2 levels approach baseline when a normal MAP is reached during volume resuscitation. In contrast, a significantly higher MAP was required to return to baseline CrSO2 during blood pressure management with phenylephrine (P < .0001). Evaluation of carotid blood flow and CrSO2 indicated that during induction of hypovolemia, the two measures are strongly correlated. In contrast, there was limited correlation between carotid blood flow and CrSO2 during blood infusion.

CONCLUSIONS

This study demonstrated that it is possible to restore CrSO2 by manipulating MAP with vasoconstriction, even in profound hypotension. However, MAP manipulation may result in unintended consequences for other organs, such as the kidney, if the tissue is not reoxygenated sufficiently. The clinical implications of these results and how best to respond to hypovolemia in the pre-hospital and hospital settings should be elucidated by additional studies.

The preventive effect of 5-hydroxytryptamine-3 receptor antagonist on blood pressure reduction and postoperative nausea and vomiting during general anesthesia induction: A double-blinded, randomized controlled trial

STUDY OBJECTIVE

Administering a 5-hydroxytryptamine-3 receptor (5-HT3) at anesthesia induction may aid in achieving hemodynamic stability during general anesthesia induced using opioids. Therefore, we aimed to evaluate the effect of ramosetron, a 5-HT3 antagonist, administered on hypotension at the induction of total intravenous anesthesia (TIVA) with propofol and remifentanil. Additionally, we aimed to compare the impact of ramosetron administration at anesthesia induction versus that at the end of the surgery on postoperative nausea and vomiting (PONV).

DESIGN

Patients were randomly allocated to the Induction group (administration of ramosetron [0.3 mg/5 ml] at anesthesia induction and normal saline [5 ml] at the end of the surgery) or End group (administration of normal saline [5 ml] at anesthesia induction and ramosetron [0.3 mg/5 ml] at the end of the surgery). Hemodynamic status, PONV, and postoperative pain were assessed.

SETTING

Operating room, post-anesthetic care unit, and general ward.

PATIENTS

In total, 176 non-smoking patients without any past medical history undergoing laparoscopic gynecological surgeries under TIVA were included in the study.

MEASUREMENTS

Blood pressure (BP), heart rate, PONV, visual analog scale (VAS).

MAIN RESULTS

The Induction group exhibited significantly higher BP at anesthesia induction and required significantly lower doses of phenylephrine and ephedrine during anesthesia than the End group had. However, PONV and postoperative pain were similar between the two groups.

CONCLUSIONS

Administering ramosetron at anesthesia induction resulted in significantly better hemodynamic stability with significantly lesser requirement of phenylephrine and ephedrine than administering at the end of the surgery did. Therefore, we recommend ramosetron administration at anesthesia induction rather than at the end of the surgery to prevent PONV and the decrease in the mean BP during TIVA with propofol and remifentanil.

The effect of combining prewarming with intraoperative phenylephrine infusion on the prevention of hypothermia in patients undergoing urological surgery: a prospective, randomized, and controlled trial

Background: Hypothermia is common in patients undergoing urological surgery; however, no single preventative modality is completely effective. This study evaluated the effects of combining prewarming with intraoperative phenylephrine infusion for the prevention of hypothermia in patients undergoing urological surgery. Methods: This prospective study enrolled 58 patients scheduled for urological surgery under general anesthesia. The patients were randomized into two groups (n = 29). Patients in the experimental (prewarming and phenylephrine infusion) group (PP group) received prewarming for 20 min and intraoperative phenylephrine infusion, whereas those in the control group (C group) received no active prewarming with only intermittent administration of vasoactive agents. The patient's sublingual temperatures before and after anesthesia and nasopharyngeal temperature during anesthesia were recorded as core temperatures. Results: The incidence of intraoperative hypothermia was higher in the C group than in the PP group (57.7% [15/26] vs. 23.1% [6/26], P = 0.01). The severity of intraoperative hypothermia was higher in the C group than in the PP group (P = 0.004). The nasopharyngeal temperature at the end of surgery was lower in the C group than in the PP group (35.8 ± 0.6°C vs. 36.3 ± 0.4°C, P = 0.002). The trend of core temperature decline during the first hour after anesthesia induction differed between the two groups (P = 0.003; its decline was more gradual in the PP group). Conclusions: The combination of prewarming for 20 min and intraoperative phenylephrine infusion reduced the incidence and severity of intraoperative hypothermia and modified the trend of decreasing core temperatures in patients undergoing urological surgery.

Application of Gd2ZnMnO6/ZnO nanocomposite for electrochemical measurement of acetaminophen, diphenhydramine, and phenylephrine

An electrochemical sensor with high sensitivity was designed and used to measure several drugs, including acetaminophen (AC), diphenhydramine (DPH), and phenylephrine (PHE). This sensor was created using a carbon paste electrode (CPE) that has been modified with a Gd2ZnMnO6/ZnO nanocomposite. In order to analyze the developed sensor, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR) techniques were used. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, chronoamperometry, and apparent resistance spectroscopy methods. Also, the compound's diffusion coefficient (D) was calculated. By using the differential pulse voltammetry, AC, DPH, and PA were determined with detection limits of 2.5 × 10-8, 3.3 × 10-8, and 1.4 × 10-8 M in the linear concentration ranges of 0.09-900 μM. Finally, the designed sensor was utilized to measure the drug in real samples, and acceptable results were obtained.

Predictability of the Phenylephrine Test in Congenital Ptosis: Ten Years of Experience

PURPOSE

To assess the predictability of phenylephrine testing for congenital ptosis and review outcomes of Müller's Muscle-conjunctival resection (MMCR) for congenital ptosis across ten years of follow-up.

METHODS

In this retrospective case series, all patients who underwent MMCR for congenital ptosis at a single institution between 2010 and 2020 were identified. Exclusion criteria included patients who had not undergone preoperative testing with 2.5% phenylephrine in the superior fornix; patients who underwent revision surgery; and patients who had a broken suture in the early postoperative period. Demographics, margin-reflex distance 1 (MRD1) values pre- and postphenylephrine, millimeters of tissue resected intraoperatively, and final postoperative MRD1 were recorded.

RESULTS

A total of 28 patients were included; 19 patients received MMCR and 9 patients received a combined MMCR plus tarsectomy. The amount of tissue resected ranged from 5 to 11 mm. There was no significant difference between median postphenylephrine MRD1 and median final postoperative MRD1 in either surgical group. Neither patient age nor levator function was significantly associated with a change in MRD1 in either group. The addition of a tarsectomy had no bearing on the final MRD1 value.

CONCLUSIONS

MMCR is a viable option for patients with congenital ptosis and moderate levator function with a response to phenylephrine. In these patients, MRD1 after 2.5% phenylephrine testing correlates to the final postoperative MRD1 outcome within 0.5 mm.

Effect of preoperative oral rehydration before cesarean section on ultrasound assessment of gastric volume and intraoperative hemodynamic changes: a randomized controlled trial

BACKGROUND

Cesarean section often requires an urgent transfusion load due to decreased blood pressure after spinal anesthesia. This prospective randomized study aimed to investigate whether a preoperative oral rehydration solution (ORS) stabilized perioperative circulatory dynamics.

METHODS

Sixty-three parturients scheduled for cesarean section under combined spinal epidural anesthesia (CSEA) were randomly allocated to one of three groups: Group O received 500 mL ORS before bedtime and 500 mL 2 h before CSEA; Group M received mineral water instead of ORS; and Group C had no fluid intake (controls). After entering the operating room, stomach size was measured using ultrasound. Blood samples were obtained, and CSEA was induced. Vasopressors were administered when systolic blood pressure was < 90 mmHg or decreased by > 20%. As a vasopressor, phenylephrine (0.1 mg) was administered at ≥ 60 beats/min heart rate or ephedrine (5 mg) at < 60 beats/min heart rate. The primary outcome was the total number of vasopressor boluses administered. Secondary outcomes were the cross-sectional area of the stomach antrum, maternal plasma glucose levels, serum sodium levels, total intravenous fluid, bleeding volume, urine volume, operative time, and cord blood gas values after delivery.

RESULTS

The total number of vasopressor boluses was lower in Group O than in Group C (P < 0.05). Group O had lower total dose of phenylephrine than Group C (P < 0.05). There were no significant differences between Group M and other groups. No differences were detected regarding secondary outcomes.

CONCLUSIONS

In women scheduled for cesarean section, preoperative ORS stabilized perioperative circulatory dynamics. Neither ORS nor mineral water consumption increased the stomach content volume.

TRIAL REGISTRATION

This trial is registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN000019825: Date of registration 17/11/2015).

Early-onset hereditary isolated non-neurogenic orthostatic hypotension in a Swedish family

PURPOSE

Orthostatic hypotension is a common condition with heterogeneous and, in many cases, unclear underlying pathophysiology. Frequent symptoms are syncope and falls with a strong impact on daily life. A two-generation family with eight individuals segregating early-onset severe orthostatic hypotension with persistent tachycardia in upright position and repeated faints was identified. Our aim was to elucidate the underlying pathophysiology.

METHODS

One severely affected individual underwent thorough investigation with neurophysiological and blood pressure (BP) measurements, including direct recording of baroreflex-governed sympathetic nerve signalling and induction of BP rise with phenylephrine. Family members underwent parts of the examination. Genetic analysis using exome sequencing was performed.

RESULTS

Marked postural hypotension with greatly reduced cardiac preload was observed, but without signs of autonomic nervous system dysfunction: sympathetic nerve signalling was normal, as were catecholamine levels, and phenylephrine stimulation revealed a normal increase in BP. The results of the genetic analysis using exome sequencing comprising all known genes associated with the regulation of BP and catecholamine metabolism were normal.

CONCLUSION

The combined findings suggest an autosomal dominant form of early-onset orthostatic hypotension with variable clinical expression and without any additional autonomic dysfunction. It is possible that further investigation will reveal an as yet undescribed entity of orthostatic hypotension transmitted as an autosomal dominant trait.

Norepinephrine preserved flap blood flow compared to phenylephrine in free transverse rectus abdominis myocutaneous flap breast reconstruction surgery: A randomized pilot study

BACKGROUND

Vasopressors are used in up to 85% of cases during free flap surgery. However, their use is still debated with concerns of vasoconstriction-related complications, with rates up to 53% in minor cases. We investigated the effects of vasopressors on flap blood flow during free flap breast reconstruction surgery. We hypothesized that norepinephrine may preserve flap perfusion better than phenylephrine during free flap transfer.

METHODS

A randomized pilot study was performed in patients undergoing free transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction. Patients with peripheral artery disease, allergies to study drugs, previous abdominal operations, left ventricular dysfunction, or uncontrolled arrhythmias were excluded. Twenty patients were randomized to receive either norepinephrine (0.03-0.10 µg/kg/min) or phenylephrine (0.42-1.25 µg/kg/min) (each n = 10) to maintain a mean arterial pressure of 65-80 mmHg. The primary outcome was differences in mean blood flow (MBF) and pulsatility index (PI) of flap vessels after anastomosis measured using transit time flowmetry in the two groups. Secondary outcomes included flap loss, necrosis, thrombosis, wound infection, and reoperation within 7 days postoperatively.

RESULTS

After anastomosis, MBF showed no significant change in the norepinephrine group (mean difference, -9.4 ± 14.2 mL/min; p = 0.082), whereas it was reduced in the phenylephrine group (-7.9 ± 8.2 mL/min; p = 0.021). PI did not change in either group (0.4 ± 1.0 and 1.3 ± 3.1 in the norepinephrine and phenylephrine groups; p = 0.285 and 0.252, respectively). There were no differences in secondary outcomes between the groups.

CONCLUSION

During free TRAM flap breast reconstruction, norepinephrine seems to preserve flap perfusion compared to phenylephrine. However, further validation studies are required.

Prevalence and Predictors of Hering's Response in Müller's Muscle-conjunctival Resection

PURPOSE

Determine the prevalence and predictors of Hering's response following Muller's muscle-conjunctival resection (MMCR).

METHODS

Seventy-five consecutive patients undergoing unilateral MMCR were recruited in this prospective, multicenter, cohort study. Margin-reflex distance-1 (MRD1) of both eyelids was recorded preoperatively and postoperatively. One hundred forty-three variables were investigated as potential predictors of a late postoperative (≥3 months) Hering's response using regression analyses. Main outcome measures were Hering's response (≥0.5 mm descent of the unoperated eyelid from baseline), and a clinically relevant Hering's response (descent of the unoperated from baseline to a MRD1 ≤ 2.0 mm, or descent from baseline such that the MRD1 of the unoperated eyelid became >1 mm lower than the operated eyelid).

RESULTS

Twenty-four (32.0%) patients had a late postoperative Hering's response, but only 6 (8.0%) responses were clinically relevant. A Hering's response at the immediate (OR 16.24, p = 0.02) and 1-week postoperative (OR 8.94, p = 0.04) timepoints predicted a late postoperative response. However, the presence (OR 7.84, p = 0.07) and amplitude (OR 8.13, p = 0.06) of a preoperative phenylephrine Hering's response did not predict a late postoperative response. Of the 10 patients with a clinically relevant phenylephrine Hering's response, only 1 demonstrated a clinically relevant response late postoperatively.

CONCLUSION

Unilateral MMCR induces a clinically relevant Hering's response in 8% of patients. A preoperative phenylephrine Hering's response does not predict a late postoperative Hering's response. Therefore, when unilateral phenylephrine testing unmasks contralateral blepharoptosis, only the side with blepharoptosis at baseline should be operated.

Müller Muscle Conjunctival Resection: A Multicentered Prospective Analysis of Surgical Success

PURPOSE

This is a multicenter prospective cohort study investigating Müller muscle conjunctival resection success rates based on marginal reflex distance-1 (MRD1) and symmetry criteria. A secondary objective was to identify predictors of success.

METHODS

One hundred fifty-two patients with unilateral or bilateral blepharoptosis (229 eyelids) undergoing Müller muscle conjunctival resection were consecutively recruited from 2015 to 2020 at the Université de Montréal and University of California San Francisco. Ptosis was defined as MRD1 ≤ 2.0 mm or MRD1 > 1 mm lower than the contralateral eyelid. Patients were selected for Müller muscle conjunctival resection surgery if they demonstrated significant eyelid elevation following phenylephrine 2.5% testing. MRD1 success (operated eyelid achieving MRD1 ≥ 2.5 mm) and symmetry success (patient achieving an intereyelid MRD1 difference ≤ 1 mm) were evaluated for the patient cohort. Predictors of MRD1 and symmetry success were analyzed using multivariate regression analysis.

RESULTS

MRD1 success was achieved in 72.1% (n = 165) of 229 operated eyelids. Symmetry success was achieved in 75.7% (n = 115) of 152 patients. MRD1 before phenylephrine testing was the only statistically significant predictor of MRD1 success (odds ratio [OR] 2.69, p = 0.001). Symmetry following phenylephrine testing was the only variable associated with increased odds of symmetry success (OR 2.71, p = 0.024), and unilateral surgery (OR 0.21, p = 0.004), the only variable associated with reduced odds of symmetry success.

CONCLUSIONS

Müller muscle conjunctival resection effectively achieves postoperative MRD1 and symmetry success. MRD1 before phenylephrine testing is the strongest determinant of MRD1 success. Neither a large rise in MRD1 with phenylephrine nor increasing tissue resection length adequately counterbalance the effect of a low MRD1 before phenylephrine. Unilateral surgery and the absence of symmetry following phenylephrine predict greater odds of symmetry failure.

[Ways to solve the problem of cross-reactions during immunochromatographic examination of biological objects]

The purpose of this review is to study the causes of cross-reactions of a number of drugs (mebeverine, phenibut, tropicamide, ramipril, metoprolol, phenylephrine, sertraline, chloropyramine and diphenhydramine) during the preliminary stage of laboratory diagnostics by immunochromatographic method and to propose a possible algorithm for solving this problem. Conducting a hair study in order to identify the fact of the use of psychoactive substances will increase the reliability of analytical diagnostics and reduce the likelihood of false positive results of the analysis. The use of a validated method of enzymatic hydrolysis of hair will eliminate unreliable results of the analysis due to the detection of the native molecule of the toxicant, increase the efficiency and accuracy of the diagnostic procedure.

Application of the C-C3N4/Li2CoMn3O8//IL nanocomposite for design a sensitive electrochemical sensor inorder to detection of cetirizine, acetaminophen and phenylephrine in biological and pharmaceuticals samples

Due to the side effects of cetirizine overdose and the need to monitor its concentration in the human body, in this work, an electrochemical sensor has been prepared by utilizing a carbon paste electrode modified with Li₂CoMn₃O₈/CC₃N₄ nanocomposite and ethyl-3-methyl-imidazolium chloride ionic liquid ([EMIM][Cl]) to determine cetirizine in the human blood serum sample and urine as well as drug samples. Li₂CoMn₃O₈/CC₃N₄ nanocomposite was characterized by Fourier transform infrared (FT-IR), field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) analysis. The investigation of the influence of each modifier component showed that the existence of all components in modification has a synergistic effect. Li₂CoMn₃O₈/CC₃N₄/IL nanocomposite has a larger surface area relative to the components alone, thus providing a more fine-grained media to facilitate electron transfer during the reaction between analyte and electrode. Determination of cetirizine was performed in phosphate buffer solution with pH 7.0 and detection limits obtained in the concentration ranges of 0.03-0.9 and 3-300 μM was 11.8 × 10^-9 M. The diffusion coefficient (D = 9.2 × 10^-6 cm²s^-1) of cetirizine at the surface of the modified electrode was determined by chronoamperometry. Finally, simultaneous detection of cetirizine, phenylephrine and acetaminophen was performed using the suggested sensor without any interference.

Definition of chemical markers for Hancornia speciosa Gomes by chemometric analysis based on the chemical composition of extracts, their vasorelaxant effect and α-glucosidase inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa Gomes (Apocynaceae) is a tree found in the Brazilian savannah, traditionally used to treat several diseases, including diabetes and hypertension. The anti-hypertensive activity of H. speciosa leaves (HSL) has been demonstrated in different models and is credited to the vasodilator effect and ACE (angiotensin-converting enzyme) inhibition. The hypoglycemic effect of HSL has been also reported.

AIM OF THE STUDY

To establish correlations between the biological activities elicited by H. speciosa extracts and the contents of their major compounds, aiming to define chemical markers related to the potential antihypertensive and antidiabetic effects of the species. Additionally, it aimed to isolate and characterize the chemical structure of a marker related to the α-glucosidase inhibitory effect.

MATERIALS AND METHODS

Extracts of a single batch of H. speciosa leaves were prepared by extraction with distinct solvents (ethanol/water in different proportions; methanol/ethyl acetate), employing percolation or static maceration as extraction techniques, at different time intervals. The contents of chlorogenic acid, rutin and FlavHS (a tri-O-glycoside of quercetin) were quantified by a developed and validated HPLC-PDA method. Bornesitol was determined by HPLC-PDA after derivatization with tosyl chloride, whereas total flavonoids were measured spectrophotometrically. Identification of other constituents in the extracts was performed by UPLC-DAD-ESI-MS/MS analysis. The vasorelaxant activity was assayed in rat aortic rings precontracted with phenylephrine, and α-glucosidase inhibition was tested in vitro. Principal component analysis (PCA) was employed to evaluate the contribution of each marker to the biological responses. Isolation of compound 1 was carried out by column chromatography and structure characterization was accomplished by NMR and UPLC-DAD-ESI-MS/MS analyses.

RESULTS

The contents of the chemical markers (mean ± s.d. % w/w) varied significantly among the extracts, including total flavonoids (2.68 ± 0.14 to 5.28 ± 0.29), bornesitol (5.11 ± 0.26 to 7.75 ± 0.78), rutin (1.46 ± 0.06 to 1.97 ± 0.02), FlavHS (0.72 ± 0.05 to 0.94 ± 0.14) and chlorogenic acid (0.67 ± 0.09 to 0.91 ± 0.02). All extracts elicited vasorelaxant effect (pIC₅₀ between 4.97 ± 0.22 to 6.48 ± 0.10) and α-glucosidase inhibition (pIC₅₀ between 3.49 ± 0.21 to 4.03 ± 0.10). PCA disclosed positive correlations between the vasorelaxant effect and the contents of chlorogenic acid, rutin, total flavonoids, and FlavHS, whereas a negative correlation was found with bornesitol concentration. No significant correlation between α-glucosidase inhibition and the contents of the above-mentioned compounds was found. On the other hand, PCA carried out with the areas of the ten major peaks from the chromatograms disclosed positive correlations between a peak ascribed to co-eluted triterpenes and α-glucosidase inhibition. A triterpene was isolated and identified as 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol.

CONCLUSION

According to PCA results, the vasorelaxant activity of H. speciosa extracts is related to flavonoids and chlorogenic acid, whereas the α-glucosidase inhibition is associated with lipophilic compounds, including esters of lupeol like 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol, described for the first time for the species. These compounds can be selected as chemical markers for the quality control of H. speciosa plant drug and derived extracts.

Carvedilol ameliorates dexamethasone-induced myocardial injury in rats independent of its action on the α1-adrenergic receptor

The current study aimed to investigate the cardiotoxic effect of dexamethasone-high-dose in rats, the therapeutic effect of carvedilol and the role of α1-adrenergic receptor (α1AR). The experiment involved 6 groups: control, dexamethasone (10 mg/kg), carvedilol (10 mg/kg), phenylephrine (1 mg/kg), phenylephrine plus carvedilol and propranolol (30 mg/kg). Drugs and vehicles were given for 7 days. Dexamethasone was given with the drugs in the last 4 groups. On the 8th-day and after overnight fasting, serum and cardiac samples were collected. Serum levels of cardiac troponin I and creatine kinase-myoglobin as well as cardiac levels of diacylglycerol, malondialdehyde, kinase activity of Akt, transforming growth factor-β, Smad3 and alpha smooth muscle actin were measured. Cardiac samples were also used for histopathological examination using hematoxylin-eosin and Sirius red stains, in addition to immunohistochemical examination using β-arrestin2 antibody. Dexamethasone induced cardiac injury via increasing oxidative stress, apoptosis and profibrotic signals. Carvedilol significantly reduced the dexamethasone-induced cardiotoxicity. Using phenylephrine, a competitive α1-agonist, with carvedilol potentiated the cardioprotective actions of carvedilol. Propranolol, a β-blocker without activity on α1ARs, showed higher cardiac protection than carvedilol. Dexamethasone-high-dose upregulates cardiac oxidative stress, apoptotic and profibrotic signals and induces cardiac injury. Blocking the α1-adrenergic receptor by carvedilol attenuates its cardioprotective effects against dexamethasone-induced cardiotoxicity.

Auraptene, a citrus peel-derived natural product, prevents myocardial infarction-induced heart failure by activating PPARα in rats

BACKGROUND

Auraptene derived from the peel of Citrus hassaku possesses anti-tumor, anti-inflammatory, and neuroprotective activities. Thus, it could be a valuable pharmacological alternative to treat some diseases. However, the therapeutic value of auraptene for heart failure (HF) is unknown.

STUDY DESIGN/METHODS

In cultured cardiomyocytes from neonatal rats, the effect of auraptene on phenylephrine-induced hypertrophic responses and peroxisome proliferator-activated receptor-alpha (PPARα)-dependent gene transcriptions. To investigate whether auraptene prevents the development of heart failure after myocardial infarction (MI) in vivo, Sprague-Dawley rats with moderate MI (fractional shortening < 40%) were randomly assigned for treatment with low- or high-dose auraptene (5 or 50 mg/kg/day, respectively) or vehicle for 6 weeks. The effects of auraptene were evaluated by echocardiography, histological analysis, and the measurement of mRNA levels of hypertrophy, fibrosis, and PPARα-associated genes.

RESULTS

In cultured cardiomyocytes, auraptene repressed phenylephrine-induced hypertrophic responses, such as increases in cell size and activities of atrial natriuretic factor and endothelin-1 promoters. Auraptene induced PPARα-dependent gene activation by enhancing cardiomyocyte peroxisome proliferator-responsive element reporter activity. The inhibition of PPARα abrogated the protective effect of auraptene on phenylephrine-induced hypertrophic responses. In rats with MI, auraptene significantly improved MI-induced systolic dysfunction and increased posterior wall thickness compared to the vehicle. Auraptene treatment also suppressed MI-induced increases in myocardial cell diameter, perivascular fibrosis, and expression of hypertrophy and fibrosis response markers at the mRNA level compared with vehicle treatment. MI-induced decreases in the expression of PPARα-dependent genes were improved by auraptene treatment.

CONCLUSIONS

Auraptene has beneficial effects on MI-induced cardiac hypertrophy and left ventricular systolic dysfunction in rats, at least partly due to PPARα activation. Further clinical studies are required to evaluate the efficacy of auraptene in patients with HF.

Cardiomyocyte BRAF is a key signalling intermediate in cardiac hypertrophy in mice

Cardiac hypertrophy is necessary for the heart to accommodate an increase in workload. Physiological, compensated hypertrophy (e.g. with exercise) is reversible and largely due to cardiomyocyte hypertrophy. Pathological hypertrophy (e.g. with hypertension) is associated with additional features including increased fibrosis and can lead to heart failure. RAF kinases (ARAF/BRAF/RAF1) integrate signals into the extracellular signal-regulated kinase 1/2 cascade, a pathway implicated in cardiac hypertrophy, and activation of BRAF in cardiomyocytes promotes compensated hypertrophy. Here, we used mice with tamoxifen-inducible cardiomyocyte-specific BRAF knockout (CM-BRAFKO) to assess the role of BRAF in hypertension-associated cardiac hypertrophy induced by angiotensin II (AngII; 0.8 mg/kg/d, 7 d) and physiological hypertrophy induced by phenylephrine (40 mg/kg/d, 7 d). Cardiac dimensions/functions were measured by echocardiography with histological assessment of cellular changes. AngII promoted cardiomyocyte hypertrophy and increased fibrosis within the myocardium (interstitial) and around the arterioles (perivascular) in male mice; cardiomyocyte hypertrophy and interstitial (but not perivascular) fibrosis were inhibited in mice with CM-BRAFKO. Phenylephrine had a limited effect on fibrosis but promoted cardiomyocyte hypertrophy and increased contractility in male mice; cardiomyocyte hypertrophy was unaffected in mice with CM-BRAFKO, but the increase in contractility was suppressed and fibrosis increased. Phenylephrine induced a modest hypertrophic response in female mice and, in contrast with the males, tamoxifen-induced loss of cardiomyocyte BRAF reduced cardiomyocyte size, had no effect on fibrosis and increased contractility. The data identify BRAF as a key signalling intermediate in both physiological and pathological hypertrophy in male mice, and highlight the need for independent assessment of gene function in females.

Acute Angle-Closure Attacks Are Uncommon in Primary Angle-Closure Suspects after Pharmacologic Mydriasis: The Zhongshan Angle-Closure Prevention Trial

PURPOSE

Angle-closure glaucoma is a major cause of blindness worldwide that carries an excessive risk of severe, bilateral visual impairment. A common concern among clinicians is the precipitation of acute angle-closure (AAC) attacks because of mydriasis. We evaluated the risk of AAC after pharmacologic dilation in Chinese individuals classified as having bilateral primary angle-closure suspects (PACSs).

DESIGN

Randomized, interventional, controlled trial.

PARTICIPANTS

A total of 889 patients with bilateral PACSs, aged between 50 and 70 years, were identified through community screening in Guangzhou, China, and enrolled in the study.

METHODS

In the Zhongshan Angle-Closure Prevention Trial, bilateral PACSs were treated with laser peripheral iridotomy (LPI) in 1 randomly selected eye, with the fellow eye serving as an untreated control. Over 72 months of follow-up, the participants had their pupils pharmacologically dilated 6 times with 5% phenylephrine and 0.5% tropicamide.

MAIN OUTCOME MEASURES

Incidence and risk of post-mydriasis AAC in LPI-treated and untreated, control eyes classified as PACSs.

RESULTS

One bilateral AAC attack occurred after mydriasis at the 2-week post-LPI visit. No other AAC events occurred in the LPI-treated eyes. In the untreated eyes, 4 additional attacks occurred: 2 occurred after dilation (1 at 54 months and 1 at 72 months of follow-up) and 2 occurred spontaneously. The risk of post-mydriasis AAC in the untreated eyes was 1 attack in 1587 dilations. The risk of spontaneous AAC in the untreated eyes was 0.44 per 1000 eye-years (95% confidence interval, 0.11-1.77 per 1000 eye-years).

CONCLUSIONS

The risk of incident AAC attacks in PACSs was extremely low, even in a higher-risk group that underwent repeated pharmacologic pupillary dilation over 6 years of follow-up. Prophylactic LPI reduced this small but real risk. This trial was registered at ISRCTN.com as ISRCTN45213099.

Anesthetic Management of Gastrointestinal Carcinoid Tumors: A Case Report

Carcinoid tumors are neuroendocrine tumors (NET) that secrete hormones and other substances into the circulation, causing shifts in hemodynamics and other unpleasant symptoms. This case report describes a case in which the patient had a midgut NET that metastasized to the liver, causing carcinoid syndrome. The patient underwent general anesthesia for an exploratory laparotomy, small bowel resection with anastomosis, mesenteric mass resection, and a right liver lobectomy. The patient had carcinoid syndrome and developed carcinoid crisis during the surgery. Octreotide and phenylephrine infusions and phenylephrine boluses were used during the procedure to stabilize hemodynamics. The pathophysiology of carcinoid tumors, carcinoid syndrome, carcinoid crisis, and carcinoid heart disease are reviewed and octreotide application in the setting of carcinoid syndrome and carcinoid crisis is also reviewed. Octreotide is a first-generation somatostatin analog that binds to somatostatin receptor 2 with high affinity, somatostatin receptor 3 and somatostatin receptor 5 with lower affinity, and suppresses the secretion of serotonin. Anesthesia recommendations are given for patients undergoing surgery with carcinoid syndrome.

Prevention of vasoplegia with CytoSorb in heart failure patients undergoing cardiac surgery (CytoSorb-HF trial): protocol for a randomised controlled trial

INTRODUCTION

Vasoplegia is a common complication after cardiac surgery and is associated with poor prognosis. It is characterised by refractory hypotension despite normal or even increased cardiac output. The pathophysiology is complex and includes the systemic inflammatory response caused by cardiopulmonary bypass (CPB) and surgical trauma. Patients with end-stage heart failure (HF) are at increased risk for developing vasoplegia. The CytoSorb adsorber is a relatively new haemoadsorption device which can remove circulating inflammatory mediators in a concentration based manner. The CytoSorb-HF trial aims to evaluate the efficacy of CytoSorb haemoadsorption in limiting the systemic inflammatory response and preventing postoperative vasoplegia in HF patients undergoing cardiac surgery with CPB.

METHODS AND ANALYSIS

This is an investigator-initiated, single-centre, randomised, controlled clinical trial. In total 36 HF patients undergoing elective cardiac surgery with an expected CPB duration of more than 120 min will be randomised to receive CytoSorb haemoadsorption along with standard surgical treatment or standard surgical treatment alone. The primary endpoint is the change in systemic vascular resistance index with phenylephrine challenge after CPB. Secondary endpoints include inflammatory markers, sublingual microcirculation parameters and 30-day clinical indices. In addition, we will assess the cost-effectiveness of using the CytoSorb adsorber. Vascular reactivity in response to phenylephrine challenge will be assessed after induction, after CPB and on postoperative day 1. At the same time points, and before induction and on postoperative day 4 (5 time points in total), blood samples will be collected and the sublingual microcirculation will be recorded. Study participants will be followed up until day 30.

ETHICS AND DISSEMINATION

The trial protocol was approved by the Medical Ethical Committee of Leiden The Hague Delft (METC LDD, registration number P20.039). The results of the trial will be published in peer-reviewed medical journals and through scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04812717.

[A prospective cohort study on refractive status of schoolchildren in Huangzhong District, Xining City, Qinghai Province]

Objective: To determine the characteristics and progress of the visual acuity and refractive state of schoolchildren in Huangzhong District, Xining City, Qinghai Province in China. Methods: Cohort study. Department of Ophthalmology, Beijing Children's Hospital carried out a cohort study by collecting the visual acuity and refractive state of Grade 1-5 schoolchildren among 16 primary schools in Huangzhong District, Xining City, Qinghai Province in September 2020 and July 2021. Cycloplegic retinoscopy with eye drop which contained tropicamide (0.5%) and phenylephrine hydrochloride (0.5%) was performed in children with low vision(<1.0). Myopia was defined as the spherical equivalent (SE) ≤-0.5 D after cycloplegic retinoscopy. Measurement data was analyzed by t-test and enumeration data was analyzed by χ² test. Multiple linear regression was used to analyze the influencing factors. Results: The 2 489 individuals with repeated tests in two years were included in the follow-up study, among whom the prevalence of myopia was 26.24%(653/2 489) in 2020, while 32.94% (820/2 489)respectively in 2021. The incidence of myopia in one school year from grades 1 to 5 was 11.19%(47/420), 5.44%(21/386), 6.39%(25/391), 11.52%(44/382) and 11.67%(30/257). The average SE of children in all grades in 2021 increased negatively from the previous year (Grade 1 to Grade 5 increased respectively: 0.40 D, 0.69 D, 0.62 D, 0.52 D and 0.37 D). Conclusions: The prevalence of myopia among schoolchildren in Huangzhong District, Xining City, Qinghai Province was relatively high. There were two peaks of myopia incidence in the first, fourth and fifth grades. Female, age, and the baseline of SE were the related influencing factors for myopia progression.

Effect of Weight-Adjusted Phenylephrine, Norepinephrine, and Metaraminol for Elective Cesarean Delivery on Neonatal Acid–Base Status: A Randomized Controlled Trial

Purpose

Many previous trials have compared the effects of different vasoactive drugs on cesarean section patients, but their infusion rate is based on experience rather than high-quality evidence. It is difficult to judge whether the effect of vasoactive drug comes from the better choice or a more appropriate at rates of vasoactive drugs. The effect of vasoactive drugs at the rates of the 90% effective dose needs to be verified and compared.

Patients and Methods

Women undergoing elective caesarean delivery under combined spinal-epidural anaesthesia were randomized to receive phenylephrine or norepinephrine or metaraminol infusion at the rate that was assumed to be the 90% effective dose. Anesthetic management was standardized and included fluid loading with 10 mL/kg of Ringer. The primary outcome was the umbilical artery pH.

Results

78 patients were included. The umbilical artery pH was not significantly different among the three groups (phenylephrine group: 7.33 ± 0.03 vs norepinephrine group: 7.33 ± 0.04 vs metaraminol group: 7.33 ± 0.04, P = 0.99). There were no significant differences in the incidence of hypotension, hypertension, bradycardia, and nausea and vomiting among the three groups. The SBP of the phenylephrine group was significantly higher than that of the metaraminol group (adjustive P value = 0.005).

Conclusion

Phenylephrine (0.54 μg/kg/min) or metaraminol (2 μg/kg/min) or norepinephrine (0.08 μg/kg/min) administered to healthy patients with elective cesarean section after spinal anesthesia has no significant effect on the acid-base balance of the fetus.

The association of maternal obesity with fetal pH in parturients undergoing cesarean delivery under spinal anesthesia

OBJECTIVE

The aim of this study was to examine the relationship between maternal obesity and fetal umbilical arterial pH in a cohort of parturients that received a prophylactic phenylephrine infusion for management of spinal anesthesia induced hypotension during cesarean delivery.

METHODS

This was a retrospective cohort study of cesarean deliveries at a single academic tertiary care institution between January 2012 and March 2019. All scheduled nonlaboring cesarean deliveries of singleton live neonate performed under spinal anesthesia between 37 and 41 weeks gestational age were included. The primary outcome was umbilical arterial pH. Multiple regression models were used to test the relationship between umbilical arterial pH, and maternal body mass index (BMI), race, dose of phenylephrine, baseline systolic blood pressure, maximum decrease in systolic blood pressure, induction of anesthesia to delivery time and uterine incision to delivery time.

RESULTS

Seven hundred and sixty-one mother neonate pairs were included in the study. The univariate analysis showed a decrease in mean umbilical arterial pH with increasing maternal BMI (p = <.01). A multivariate regression model indicated that maximum decrease in systolic blood pressure, induction of anesthesia to delivery time, and uterine incision to delivery time accounted for 11% of the variance in the outcome, R² = 0.11. BMI was not a significant predictor of low umbilical arterial pH (p = .36). The significant predictors of low umbilical arterial pH in the model were maximum decrease in systolic blood pressure (p < .001), induction of anesthesia to delivery time (p = .04), and uterine incision to delivery time (p < .001).

CONCLUSIONS

Maternal BMI is not associated with lower umbilical arterial pH in women having scheduled cesarean delivery under spinal anesthesia. Severity of spinal anesthesia induced hypotension is greater with increasing BMI and may be responsible for the observed decrease in umbilical arterial pH.

Effect of selective dopamine D3 and D4 receptor agonists on trunk pulmonary artery vascular reactivity from control and monocrotaline-treated rats

Dopamine D1-like and D2-like receptors are expressed in the pulmonary arteries, however there is a little information about their effect on vascular tone in pulmonary circulation, even the vascular effect of activation of the dopamine D₃ and D₄ subtypes in physiological and pathological conditions such as pulmonary hypertension is unknown. The objective of this study was to evaluate the vascular response of trunk pulmonary artery rings from saline and monocrotaline-treated rats in the presence of selective dopamine receptor agonists. In trunk pulmonary artery rings with intact and denuded endothelium, cumulative concentration-response curves were performed for phenylephrine, acetylcholine, and dopamine receptor agonists (apomorphine-D2-like, SKF38393-D₁, quinpirole-D₂/D₃, 7-OH-DPATD₃, and PD168077-D₄) alone and in the presence of corresponding selective dopamine receptor antagonists (SCH23390-D₁, raclopride-D₂/D₃, U99194 maleate-D₃, and L-745,870-D₄). Contractile and relaxant effects generated during the activation with phenylephrine and acetylcholine, respectively, were significantly reduced in intact and denuded endothelium trunk pulmonary artery rings from monocrotaline rats in comparison with control rats. All dopamine receptor agonists, except the 7-OH-DPAT, produced significant vascular relaxation in intact trunk pulmonary artery rings precontracted with phenylephrine in both experimental groups. Also, the vascular relaxation of SKF38393, and particularly apomorphine and PD168077 was significant in denuded endothelium trunk pulmonary artery rings from control and monocrotaline groups. Furthermore, the vasorelaxation induced by these dopamine agonists was significantly reduced in pulmonary preparations from monocrotaline-treated rats in comparison to that recorded in preparations from control rats. The effect of dopamine receptor agonists decreased significantly in the presence of the corresponding antagonist in both experimental groups. The results support that dopamine D₄ receptor agonist induces significant vascular relaxation, whereas dopamine D₃ receptor agonist induces vasoconstriction in intact and denuded endothelium trunk pulmonary artery rings in control and monocrotaline-induced pulmonary arterial hypertension rats.

Comparison of carbetocin as a bolus or an infusion with prophylactic phenylephrine on maternal heart rate during Cesarean delivery under spinal anesthesia: a double-blinded randomized controlled trial

PURPOSE

Carbetocin, an oxytocin analog, given as a postpartum hemorrhage prophylaxis in elective Cesarean deliveries, frequently causes tachycardia and hypotension. Phenylephrine infusion has been shown to prevent spinal anesthesia-induced hypotension. The goal of this study was to evaluate if a slow infusion of carbetocin would reduce maternal heart rate variation and hemodynamic disturbances compared with a rapid bolus in parturients receiving a prophylactic phenylephrine infusion during elective Cesarean delivery.

METHODS

In this double-blinded randomized controlled trial, 70 healthy parturients were allocated to either a bolus group or an infusion group. At cord clamping, participants in the bolus group received carbetocin 100 µg as a rapid intravenous bolus, while participants in the infusion group received carbetocin 100 µg over 10 min. The primary outcome was the variation in maternal heart rate from baseline during the 20 min following cord clamping. Secondary outcomes included blood pressure, cardiac output, and stroke volume variations during the study period, measured with the ClearSight™ hemodynamic monitor.

RESULTS

Maximum heart rate variation was not different between the groups: bolus group, mean (standard deviation) 29.8 (25.2)% vs infusion group, 27.2 (23.3)%; P = 0.67. The increase in heart rate occurred significantly earlier in the bolus group than in the infusion group (median [interquartile range] time, 105 [69-570] sec vs 485 [255-762] sec; P = 0.02; group × time interaction: two-way repeated measures ANOVA, P = 0.04). There was no significant difference in maximum variations for the other hemodynamic parameters between the groups.

CONCLUSION

Carbetocin infused over ten minutes did not reduce the magnitude of maternal heart rate variation but delayed its occurrence. This finding could be relevant to the anesthesiologist caring for parturients in whom a slight increase in maternal heart rate is clinically undesirable.

STUDY REGISTRATION

www.

CLINICALTRIALS

gov (NCT03404544); registered 19 January 2018.

Chemometric quality assessment of Paracetamol and Phenylephrine Hydrochloride with Paracetamol impurities; comparative UV-spectrophotometric implementation of four predictive models

Spectrophotometric data analysis using multivariate approaches has many useful applications. One of these applications is the analysis of active ingredients in presence of impurities. Four chemometric-assisted spectrophotometric methods, namely, principal component regression (PCR), partial least-squares (PLS), artificial neural networks (ANN) and multivariate curve resolution-alternating least squares (MCR-ALS) were proposed and validated. The developed chemometric methods were compared to resolve the severely overlapped spectrum of Paracetamol (PAR) and Phenylephrine HCl (PHE) along with PAR impurities namely, P-Aminophenol (PAP), P-Nitrophenol (PNP), Acetanilide (ACT) and P-Chloroacetanilide (CAC). The four multivariate calibration methods succeeded in simultaneous determination of PAR and PHE with further quantification of PAR impurities. So, the proposed methods could be used with no need of any separation step and successfully applied for pharmaceutical formulation analysis. Furthermore, statistical comparison between the results obtained by the proposed chemometric methods and the official ones showed no significant differences.

An advanced double intravenous vasopressor automated system to treat hypotension during spinal anaesthesia for caesarean section: A pilot study

BACKGROUND

During spinal anaesthesia for caesarean section, haemodynamic instability may lead to maternal and foetal complications. We developed a novel advanced double intravenous vasopressor automated system (ADIVA) by using a continuous blood pressure and heart rate monitor. Treatment of hypotension was based on three criteria: the drug (phenylephrine or ephedrine) according to the heart rate; the dose of vasopressor determined by the degree of hypotension; a fast or slow bolus of vasopressor administered depending on whether there was a negative or positive gradient of SBP changes, respectively.

OBJECTIVE

The aim of this pilot study was to investigate the feasibility of the ADIVA algorithm.

DESIGN

A prospective pilot study.

SETTING

Single obstetrics and gynaecology centre in Singapore.

PATIENTS

Women undergoing elective caesarean delivery under spinal anaesthesia.

INTERVENTION

Automated administration of ephedrine or phenylephrine based on changes in blood pressure and heart rate (via the ADIVA algorithm) detected on continuous noninvasive haemodynamic monitoring using noninvasive continuous haemodynamic monitor (Nexfin).

MAIN OUTCOME MEASURES

The primary outcome was the incidence of hypotension, defined as SBP less than 80% of baseline. The secondary outcome measures were reactive hypertension, total vasopressor requirement, maternal and neonatal outcomes and system performance.

RESULTS

Forty-five women were recruited. Thirty-one women (69.9%) had at least one reading of hypotension. SBP was within ±20% of the baseline in a mean ± SD of 79.7 ± 17.6% of measurements. Forty-four (97.8%) women required phenylephrine before delivery, while 15 (33.3%) required ephedrine. No rescue medications were required. Three women (6.7%) had nausea and two (4.4%) vomiting. All neonates had APGAR scores of 9 at 5 min.

CONCLUSION

The ADIVA system, with noninvasive continuous haemodynamic monitoring, was able to maintain maternal SBP within ±20% of baseline for the vast majority of the measurements. This system had good maternal and foetal outcomes with minimal intervention from the attending anaesthetist.

TRIAL REGISTRATION

NCT03620942.

Cost analysis of mydriasis strategies in cataract surgery care in the Netherlands

PURPOSE

To investigate the economic impact of an intracameral mydriatics and anesthetic agent (ICMA), topical mydriatics, and a mydriatic ocular insert in cataract patients.

SETTING

One public hospital in the Netherlands.

DESIGN

Prospective cohort study.

METHODS

Resource use data were collected from a healthcare and societal perspective on the day of surgery. Other outcome parameters included pupil size, surgeon satisfaction, postoperative pain, and Catquest-9SF scores.

RESULTS

A total of 368 patients were included, the mean costs per patient were €506 in the ICMA group (n = 122), €474 in the ocular insert group (n = 115), and €451 in the topical group (n = 131). The acquisition cost of ICMA was highest and resulted in longer surgical time. After correction for an imbalance in the distribution of fast and slow surgeons, the mean costs in the ocular insert and topical groups were comparable (€450 vs €444). There was no statistically significant difference in the use of additional mydriatics intraoperatively (P = .521). The mean ratio of pupil size to white-to-white distance was lower in the ICMA group during all intraoperative measurements (P < .001) but similar between the topical and ocular insert groups (P range .11-.82).

CONCLUSIONS

In the investigated setting in the Netherlands, ICMA was the most costly strategy. In addition, pupil size was lowest in the ICMA group but did not result in more additional mydriasis measures intraoperatively. The ocular insert was comparable with topical mydriatics in costs and pupil size. Implementation of ICMA could be considered when availability of nurses or physical space for perioperative care is limited.

Quantifying the cost of single-use minims and multidose bottles for eye drops in routine ophthalmic practice: a multicentre study

OBJECTIVE

To compare costs between two different eye drop delivery modalities: multidose bottles and single-use minims.

DESIGN

Retrospective cohort study.

METHODS

Monthly dilating eye drop costs and quantities (tropicamide 1%, phenylephrine 2.5%, cyclopentolate 1%) were studied over a 2-year period between April 2013 and March 2015 at 2 tertiary ophthalmic centres (Royal Alexandra Hospital [RAH, Edmonton] and Rockyview General Hospital [RGH, Calgary]). In April 2014, RAH switched its dilating eye drop practice from predominantly multidose bottles to single-use minims, whereas RGH continued using predominantly multidose bottles. Eye drop volume and total and per-patient eye drop costs were quantified at RAH before switching (pre-intervention) and after (post-intervention) using an interrupted time-series analysis with RGH as a control. A counterfactual analysis was also performed. Significance was obtained using independent t-testing.

RESULTS

After switching to single-use minims, RAH experienced changes in the following: an increase in single-use minims as a proportion of total eye drop utilization (from 5.6% to 89.1%; p = 0.001), an increase in total eye drop cost by $2117 per month (95% confidence interval [CI], $1354-$2880; p < 0.001), an increase in per-patient costs by $984 per 1000 patients per month (95% CI, $674-$1293). Contrastingly, RGH did not experience similar changes. Ultimately, the cost of switching to single-use minims was $22 481 (95% CI, $7830-$31 336) over a 12-month period.

CONCLUSIONS

If safe eye drop practices are enforced via proper protocols, the use of multidose bottles may be a more cost-effective option than single-use minims for routine clinical practice.

IGF-1 protects against angiotensin II-induced cardiac fibrosis by targeting αSMA

The insulin-like growth factor 1 receptor (IGF-1R) signaling in cardiomyocytes is implicated in physiological hypertrophy and myocardial aging. Although fibroblasts account for a small amount of the heart, they are activated when the heart is damaged to promote cardiac remodeling. However, the role of IGF-1R signaling in cardiac fibroblasts is still unknown. In this study, we investigated the roles of IGF-1 signaling during agonist-induced cardiac fibrosis and evaluated the molecular mechanisms in cultured cardiac fibroblasts. Using an experimental model of cardiac fibrosis with angiotensin II/phenylephrine (AngII/PE) infusion, we found severe interstitial fibrosis in the AngII/PE infused myofibroblast-specific IGF-1R knockout mice compared to the wild-type mice. In contrast, low-dose IGF-1 infusion markedly attenuated AngII-induced cardiac fibrosis by inhibiting fibroblast proliferation and differentiation. Mechanistically, we demonstrated that IGF-1-attenuated AngII-induced cardiac fibrosis through the Akt pathway and through suppression of rho-associated coiled-coil containing kinases (ROCK)2-mediated α-smooth muscle actin (αSMA) expression. Our study highlights a novel function of the IGF-1/IGF-1R signaling in agonist-induced cardiac fibrosis. We propose that low-dose IGF-1 may be an efficacious therapeutic avenue against cardiac fibrosis.

Effects of intraoperative adrenergic administration on postoperative hyperlactatemia in open colon surgery: an observational study

Background

Postoperative Hyperlactatemia (PO-HL) is a frequent condition associated with poor prognosis. In recent years, there has been growing evidence that adrenergic stimulation may contribute to increased lactate levels. The use of adrenergic agonists for the control of intraoperative hypotension is frequent, and its impact on the development of PO-HL is unknown.

Objective

To evaluate whether the use of intraoperative adrenergic agents is associated with the occurrence of PO-HL.

Methods

This was a prospective observational study. The inclusion criteria were undergoing elective open colon surgery, being ≥60 years old and signing informed consent. The exclusion criteria were cognitive impairment, unplanned surgery, and anticipated need for postoperative mechanical ventilation. Baseline and intraoperative variables were collected, and arterial lactate data were collected at baseline and every 6 hours postoperatively for 24 hours. Hyperlactatemia was defined as lactate >2.1 mEq.L^-1.

Results

We studied 28 patients, 61% of whom developed hyperlactatemia. The variables associated with PO-HL in the univariate analysis were anesthetic time, the total dose of intraoperative ephedrine, and lower intraoperative central venous oxygen saturation (ScvO₂). Multivariate analysis confirmed the association between the use of ephedrine (p = 0.004), intraoperative hypotension (p = 0.026), and use of phenylephrine (p = 0.001) with PO-HL.

Conclusions

The use of intraoperative ephedrine, phenylephrine and intraoperative hypotension were independently associated with the development of PO-HL. This finding should lead to new studies in this field, as well as a judicious interpretation of the finding of a postoperative increase in lactate levels.

Chemometric assisted UV spectrophotometric and RP-HPLC methods for simultaneous determination of paracetamol, diphenhydramine, caffeine and phenylephrine in tablet dosage form

In this paper, Chemometric assisted UV spectrophotometric and RP-HPLC methods were developed and compared for simultaneous determination of Paracetamol, Diphenhydramine Hydrochloride, Caffeine and Phenylephrine Hydrochloride in tablet dosage form. UV-Spectrophotometric analysis was carried out by applying two chemometric models namely, Principal Component Regression method (PCR) and Partial Least Squares Regression method (PLSR). Chromatographic method was developed and optimized by applying Response surface methodology -Central Composite Design (CCD). These methods were considered first for the quantification of the drugs present in the selected formulation. PCR and PLSR models were successfully validated and applied for resolving the complex UV-spectra in the wavelength range of 240-320 nm with a data interval of 1 nm. In RP-HPLC method, the identified critical factors were methanol content (45-55% v/v) and flow rate (0.75-0.85 mL/min) and the selected responses were retention time (Rt₄) of fourth eluted component and resolution (RS_1,2) between first and second eluted components. Derringer's desirability function was used for the optimization of the chromatographic method conditions which comprised of mobile phase consisting of methanol‑potassium dihydrogen orthophosphate buffer (pH 3; 10 mM) (50: 50, v/v) and at a flow rate of 0.81 mL/min with a detection wavelength of 220 nm. One-way ANOVA in 95% confidence interval revealed that there were no significant differences among the developed methods.

Alternative mydriasis techniques for retinopathy of prematurity screening

PURPOSE

There is a large variation in mydriatic regimens used in screening for retinopathy in preterm infants. Except for the standard instillation of mydriatic drops in their commercial formulation, other techniques for pupil dilation have also been described. This study aimed to review all techniques that have been used for mydriasis in retinopathy of prematurity eye examination (ROPEE) screening.

METHODS

A comprehensive literature search was performed in PubMed, Cochrane library, Trip database, and Scopus, using the key words: "mydriasis", "techniques", "mydriatics", "dilating drops", "retinopathy of prematurity", "ROP", "phenylephrine", "cyclopentolate", "tropicamide", "smaller mydriatic drops", "reduction in drop size" to February 2019.

RESULTS

Five primary studies were included, assessing the techniques of microdrops, lower conjunctival fornix (LCF) packing and Mydriasert® ophthalmic insert. Reported efficacy was similar to commercial eyedrops instillation. Microdrops appeared to have a superior safety profile. LCF packing and Mydriasert lead to increased blood pressure, without serious complications, necessitating further safety studies.

CONCLUSIONS

Of all alternative mydriasis techniques for ROPEE screening that have been described, microdrops appear to be the safest yet still effective technique in the fragile population of premature infants in risk of ROP.