Fenoldopam Versus Nitroprusside for the Treatment of Hypertensive Emergency

Hypertension Drug Therapy

Hypertension is still the number one global killer. No matter what causes are, lowering blood pressure can significantly reduce cardiovascular complications, cardiovascular death, and total death. Unfortunately, some hypertensive individuals simply do not know having hypertension. Some knew it but either not being treated or treated but blood pressure does not achieve goal. The reasons for inadequate control of blood pressure are many. One important reason is that we are not very familiar with antihypertensive agents and less attention has been paid to comorbidities, complications as well as the hypertension-modified target organ damage in patients with hypertension. The right antihypertensive drug was not given to the right hypertensive patients at right time. This reviewer studied comprehensively the literature, hopefully that the review will help improve antihypertensive drug selection and antihypertensive therapy.

Evaluation and management of elevated blood pressures in hospitalized children

Elevated blood pressures (BP) are common among hospitalized children and, if not recognized and treated promptly, can lead to potentially significant consequences. Even though we have normative BP data and well-developed guidelines for the diagnosis and management of hypertension (HTN) in the ambulatory setting, our understanding of elevated BPs and their relationship to HTN in hospitalized children is limited. Several issues have hampered our ability to diagnose and manage HTN in the inpatient setting including the common presence of physiologic conditions, which are associated with transient BP elevations (i.e., pain or anxiety), non-standard approaches to BP measurement, a lack of clarity regarding appropriate diagnostic and therapeutic thresholds, and marginal outcome data. The purpose of this review is to highlight the issues and challenges surrounding BP monitoring, assessment of elevated BPs, and the diagnosis of HTN in hospitalized children. Extrapolating from currently available clinical practice guidelines and utilizing the best data available, we aim to provide guidelines regarding evaluation and treatment of elevated BP in hospitalized children.

An Emergency Department Approach to Drug Treatment of Hypertensive Urgency and Emergency

Patients who present with hypertensive urgency or emergency require immediate attention to assess the severity of illness. Guidelines from the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure are available but do little to address the management of acute elevations in blood pressure. Various treatment options, both old and new, exist to manage these patients in the emergency department. Decisions on therapy are patient specific and depend on the underlying cause of elevated blood pressure. This article sets out to describe specific patient presentations and reviews current available options in the management of hypertensive urgencies and emergencies.

Evaluation and treatment of hypertensive crises in children

Hypertensive crises in children are medical emergencies that must be identified, evaluated, and treated promptly and appropriately to prevent end-organ injury and even death. Treatment in the acute setting typically includes continuous intravenous antihypertensive medications with monitoring in the intensive care unit setting. Medications commonly used to treat severe hypertension have been poorly studied in children. Dosing guidelines are available, although few pediatric-specific trials have been conducted to facilitate evidence-based therapy. Regardless of what medication is used, blood pressure should be lowered gradually to allow for accommodation of autoregulatory mechanisms and to prevent cerebral ischemia. Determining the underlying cause of the blood pressure elevation may be helpful in guiding therapy.

Clevidipine for perioperative blood pressure control in infants and children

Various pharmacologic agents have been used for perioperative BP control in pediatric patients, including sodium nitroprusside, nitroglycerin, β-adrenergic antagonists, fenoldopam, and calcium channel antagonists. Of the calcium antagonists, the majority of the clinical experience remains with the dihydropyridine nicardipine. Clevidipine is a short-acting, intravenous calcium channel antagonist of the dihydropyridine class. It undergoes rapid metabolism by non-specific blood and tissue esterases with a half-life of less than 1 minute. As a dihydropyridine, its cellular and end-organ effects parallel those of nicardipine. The clevidipine trials in the adult population have demonstrated efficacy in rapidly controlling BP in various clinical scenarios with a favorable adverse effect profile similar to nicardipine. Data from large clinical trials regarding the safety and efficacy of clevidipine in children is lacking. This manuscript aims to review the commonly used pharmacologic agents for perioperative BP control in children, discuss the role of calcium channel antagonists such as nicardipine, and outline the preliminary data regarding clevidipine in the pediatric population.

A tool predicting future mean arterial blood pressure values improves the titration of vasoactive drugs

BACKGROUND

Vasoactive drug infusion rates are titrated to achieve a desired effect, e.g., mean arterial blood pressure (MAP), rather than using infusion rates based on body weight. The purpose of this study is to evaluate a method to automatically identify a patient's sensitivity to sodium-nitroprusside, dobutamine or dopamine and to evaluate, whether an advisory system that predicts MAP 5 min in the future enhances a clinician's ability to titrate sodium-nitroprusside infusions.

METHODS

We used published models implemented in MATLAB to simulate the response of 100 individual patients to infusions of sodium-nitroprusside, dopamine and dobutamine. The simulated patient's sensitivity to the three drugs was identified using an adaptive filter approach, where MAP was altered in a binary stepwise fashion. Next, 9 nurses were asked to control the MAP of 6 of the simulated patients. For half of the patients, we used the identified sensitivity to predict and display MAP 5 min into the future.

RESULTS

Identifying each individual patient's sensitivity improved the accuracy of the MAP prediction by 75% for sodium-nitroprusside, 82% for dopamine and 52% for dobutamine over the MAP prediction based on an "average" patient's sensitivity. The advisory system shortened the median time to reach the desired MAP from 10.2 to 4.1 min, decreased the median number of infusion rate changes from 6 to 4, and resulted in a significant reduction of mental workload and effort.

DISCUSSION

Patient-specific drug sensitivity identifi- cation significantly improved the prediction of future MAP. By predicting and displaying the expected MAP 5 min in the future, the advisory system helped nurses titrate faster, reduced their perceived workload and might improve patient safety.

Strategies for managing perioperative hypertension

Acute perioperative hypertension is associated with a higher risk of perioperative myocardial ischemia, bleeding, stroke, and renal failure. The immediate concern of short-term antihypertensive therapy is to prevent excessive surgical bleeding from arterial anastomoses, myocardial ischemia, and neurologic complications while causing minimal adverse effects until oral therapy can be resumed. This article reviews perioperative hypertension emergencies/urgencies and various approaches for management.

Exploring an Optimum Intra/Postoperative Management Strategy for Acute Hypertension in the Cardiac Surgery Patient

An estimated 50% of patients undergoing routine cardiac surgery require intravenous antihypertensive therapy to manage life-threatening arterial bleeding, myocardial ischemia, or cardiac failure in the perioperative period. Managing hypertension in this setting can be challenging because of the need to reduce blood pressure while maintaining adequate end organ perfusion. Hypotensive episodes can increase the risk of cardiac complications and end organ hypoperfusion, particularly in patients whose underlying cardiovascular disease has altered autoregulation of blood flow. To decrease the risk of hypertensive or hypotensive episodes, blood pressure is monitored continuously, and short-acting intravenous antihypertensive agents are administered in an effort to target a mean arterial pressure generally within 20% of the patient's baseline value. Efforts to optimize end organ perfusion and avoid recognized adverse drug effects may influence the choice of antihypertensive agents. The ideal agent for postoperative hypertension should have a rapid onset of action, be highly vascular selective, and be rapidly reversible. In addition, it should be safe, with little risk of overshoot hypotension or adverse drug reaction. Precise management of arterial pressure in the perioperative period has the potential to improve clinical outcome by avoiding hypotensive episodes, ensuring adequate end organ perfusion, decreasing the risk of adverse drug effects, and serving as a bridge to definitive long-term therapy for essential hypertension.

Therapy Insight: how changes in renal function with increasing age affect cardiovascular drug prescribing

Age is well recognized as a powerful prognostic factor in the setting of cardiovascular disease. With the aging of the US population, it is projected that more than 50 million people will be aged over 65 years by the year 2020. This growing elderly population has increased rates of morbidity and mortality owing to cardiovascular disease; however, proven therapies for prevention and treatment are often underused in older patients, largely because physicians perceive them as being frail and have limited understanding of age-related unique adverse and therapeutic effects. Advancing age is associated with a number of physiologic and pathophysiologic changes that impact the toxic effects, efficacy and dosing of many medications. Decreases in lean muscle mass affect the volume of distribution, and reductions in hepatic function affect the metabolism of many medications. Age-related reductions in renal function might have the most profound impact on the safety profile and dosing of medications in elderly patients. The strong association between renal and cardiovascular disease makes recognition of renal dysfunction and appropriate dose adjustment particularly important in elderly patients with cardiovascular disease. This article reviews current approaches to the estimation of renal function, and unique considerations related to prescribing medication for elderly patients with concomitant renal and cardiovascular disease.

Initial experience with fenoldopam after cardiac surgery in neonates with an insufficient response to conventional diuretics

OBJECTIVE

Fenoldopam, a selective dopamine-1 receptor agonist, causes systemic vasodilation and increased renal blood flow and tubular sodium excretion. We hypothesized that urine output would improve when fenoldopam was added to conventional diuretic therapy after neonatal cardiopulmonary bypass.

DESIGN

Retrospective cohort study using a time-series design.

SETTING

Pediatric cardiac intensive care unit.

PATIENTS

All neonates who received fenoldopam to promote diuresis after cardiac surgery requiring cardiopulmonary bypass from February 2002 through December 2004.

INTERVENTIONS

Fenoldopam infusion for inadequate urine output despite conventional diuretics.

MEASUREMENTS

Demographics, diagnostic information, and surgical procedures were recorded. Urine output, fluid balance, inotrope scores, diuretic doses, and other clinical variables that may influence diuresis were recorded for the 24-hr period immediately preceding fenoldopam initiation and during the initial 24 hrs of drug administration.

MAIN RESULTS

A total of 25 neonates received fenoldopam to promote diuresis after the modified Norwood (n = 14), arterial switch (n = 4), or other operations (n = 7). Heart rate, conventional diuretic dosing, and fluid intake were similar during the 24-hr periods of conventional therapy and fenoldopam use (p = not significant for all), whereas inotrope scores decreased during the study (p = .021). There was a small but statistically significant increase in blood pressure during the 48-hr study period. Median urine output was 3.6 mL x kg(-1) x hr(-1) (range, 0.2-7.2 mL x kg(-1) x hr(-1)) during the 24-hr period of conventional therapy and 5.8 mL x kg(-1) x hr(-1) (range, 1.6-11.7 mL x kg(-1) x hr(-1)) during the initial 24 hrs of fenoldopam administration (Wilcoxon's signed-rank test, p = .001).

CONCLUSIONS

Fenoldopam may improve urine output in neonates who are failing to achieve an adequate negative fluid balance despite conventional diuretic therapy after cardiac surgery and cardiopulmonary bypass. This study is limited by its retrospective design and the possibility that urine output improved spontaneously during the treatment period. A randomized, placebo-controlled clinical trial will be required to confirm these findings.

Advances in the pathogenesis and management of hypertensive crisis

PURPOSE OF REVIEW

This review summarizes recent insights into to the pathophysiology of hypertensive crisis with the emphasis on newly discovered molecular mechanisms underlying hypertension and also updates current therapeutic options for treating hypertensive crisis in children.

RECENT FINDINGS

There is growing evidence that the renin-angiotensin system plays a key role in the pathogenesis of hypertensive crises. Recent studies have shown that oxidative stress and factors affecting endothelial function are also important. Treatment of hypertensive crisis still focuses on lowering of blood pressure in an expeditious but safe manner. There is growing experience with IV nicardipine, which is becoming a viable alternative to sodium nitroprusside in children.

SUMMARY

Current knowledge of hypertensive crisis emphasizes the need for additional animal and translational studies with the goal of identifying the underlying molecular pathogenesis and developing new therapies to optimize future treatment of hypertensive emergencies.