Hypertensive Emergencies

Initial Management of Poisoned Patient

How to cite this article: Chandran J, Krishna B. Initial Management of Poisoned Patient. Indian J Crit Care Med 2019;23(Suppl 4):S234-S240.

Cardiovascular Hypertensive Crisis: Recent Evidence and Review of the Literature

Despite the high prevalence of hypertension (HTN), only a small proportion of the hypertensive patients will ultimately develop hypertensive crisis. In fact, some patients with hypertensive crisis do not report a history of HTN or previous use of antihypertensive medication. The majority of the patients with hypertensive crisis often report non-specific symptoms, whereas heart-related symptoms (dyspnea, chest pain, arrhythmias, and syncope) are less common. Hypertensive crises can be divided into hypertensive emergencies or hypertensive urgencies according to the presence or absence of acute target organ damage, respectively. This differentiation is an extremely useful classification in clinical practice since a different management is needed, which in turn has a significant effect on the morbidity and mortality of these patients. Therefore, it is very crucial for the physician in the emergency department to identify the hypertensive emergencies and to manage them through blood pressure lowering medications in order to avoid further target organ damage or deterioration. The aim of this narrative review is to summarize the recent evidence in an effort to improve the awareness, recognition, risk stratification, and treatment of hypertensive crisis in patients referred to the emergency department.

The management of acute hypertension in patients with renal dysfunction: labetalol or nicardipine?

STUDY OBJECTIVES

To compare the safety and efficacy of U.S. Food and Drug Administration (FDA)-recommended doses of labetalol and nicardipine for hypertension (HTN) management in a subset of patients with renal dysfunction (RD).

DESIGN

Randomized, open label, multicenter prospective clinical trial.

SETTING

Thirteen United States tertiary care emergency departments.

PATIENTS OR PARTICIPANTS

Subgroup analysis of the Evaluation of IV Cardene (Nicardipine) and Labetalol Use in the Emergency Department (CLUE) clinical trial. The subjects were 104 patients with RD (i.e., creatinine clearance < 75 mL/min) who presented to the emergency department with a systolic blood pressure (SBP) ≥ 180 mmHg on 2 consecutive readings and for whom the emergency physician felt intravenous antihypertensive therapy was desirable.

INTERVENTIONS

The FDA recommended doses of either labetalol or nicardipine for HTN management.

MEASUREMENTS

The number of patients achieving the physician's predefined target SBP range within 30 minutes of treatment.

RESULTS

Patients treated with nicardipine were within target range more often than those receiving labetalol (92% vs. 78%, P = 0.046). On 6 SBP measures, patients treated with nicardipine were more likely to achieve the target range on either 5 or all 6 readings than were patients treated with labetalol (46% vs. 25%, P = 0.024). Labetalol patients were more likely to require rescue medication (27% vs. 17%, P = 0.020). Adverse events thought to be related to either treatment group were not reported in the 30-minute active study period, and patients had slower heart rates at all time points after 5 minutes (P < 0.01).

CONCLUSIONS

In severe HTN with RD, nicardipine-treated patients are more likely to reach a target blood pressure range within 30 minutes than are patients receiving labetalol.

CLINICAL IMPLICATIONS

Within 30 minutes of administration, nicardipine is more efficacious than labetalol for acute blood pressure control in patients with RD.

Is pre-hospital treatment of chest pain optimal in acute coronary syndrome? The relief of both pain and anxiety is needed

BACKGROUND

Many patients who suffer from acute chest pain are transported by ambulance. It is not known how often treatment prior to hospital admission is optimal and how optimal pain-relieving treatment is defined. It is often difficult to delineate pain from anxiety.

AIM

To describe various aspects of chest pain in the pre-hospital setting with the emphasis on a) treatment and b) presumed acute coronary syndrome.

METHODS

In the literature search, we used PubMed and the appropriate key words. We included randomised clinical trials and observational studies.

RESULTS

Four types of drug appear to be preferred: 1) narcotic analgesics, 2) nitrates, 3) beta-blockers and 4) benzodiazepines. Among narcotic analgesics, morphine has been associated with the relief of pain at the expense of side-effects. Alfentanil was reported to produce more rapid pain relief. Nitrates have been associated with the relief of pain with few side-effects. Beta-blockers have been reported to increase the relief of pain when added to morphine. The combination of beta-blockers and morphine has been reported to be as effective as beta-blockers alone in pain relief, but this combination therapy was associated with more side-effects. Experience from anxiety-relieving drugs such as benzodiazepines is limited. It is not known how these 4 drugs should be combined. The results indicate that various pain-relieving treatments might modify the disease.

CONCLUSION

Our knowledge of the optimal treatment of chest pain and associated anxiety in the pre-hospital setting is insufficient. Recommendations from existing guidelines are limited. Large randomised clinical trials are warranted.

Hypertensive Emergency in Aortic Dissection and Thoracic Aortic Aneurysm-A Review of Management

Over the last few decades, treatment for aortic dissection and thoracic aortic aneurysms has evolved significantly with improvement in outcomes. Treatment paradigms include medical, endovascular and surgical options. As aortic dissection presents as a hypertensive emergency, diligent control of BP is of utmost importance in order to reduce the progression of dissection with possible aortic branch malperfusion. Treatment should begin on arrival to the emergency department and continues in the intensive care unit, endovascular suite or the operating room. Novel antihypertensive medications with improved pharmacological profile and improved surgical techniques, have improved the prognosis of patients with aortic aneurysm and/or aortic dissection. Nevertheless, morbidity and mortality remain high and hypertensive emergency poses a significant challenge in aortic dissection and thoracic aortic aneurysms.

Management of hypertensive crises

Hypertensive emergencies are life-threatening conditions because their course is complicated with acute target organ damage. They can present with neurological, renal, cardiovascular, microangiopathic hemolytic anemia, and obstetric complications. After diagnosis, they require the immediate reduction of blood pressure (in <1 hour) with intravenous drugs such as sodium nitroprusside, administered in an intensive care unit. These patients present with a mean arterial pressure >140 mm Hg and grade III to IV retinopathy. Only occasionally do they have hypertensive encephalopathy, reflecting cerebral hyperperfusion, loss of autoregulation, and disruption of the blood-brain barrier. In hypertensive emergencies, blood pressure should be reduced about 10% during the first hour and another 15% gradually over the next 2 to 3 hours to prevent cerebral hypoperfusion. The exception to this management strategy is aortic dissection, for which the target is systolic blood pressure <120 mm Hg after 20 minutes. Oral antihypertensive therapy can usually be instituted after 6 to 12 hours of parenteral therapy. Hypertensive urgencies are severe elevations of blood pressure without evidence of acute and progressive dysfunction of target organs. They demand adequate control of blood pressure within 24 hours to several days with use of orally administered agents. The purpose of this review is to provide a rational approach to hypertensive crisis management.

Does sodium nitroprusside kill babies? A systematic review

OBJECTIVE

To determine whether sodium nitroprusside causes fetal death in pregnancies complicated with hypertension.

DATA SOURCES

Medical Literature Analysis and Retrieval System Online (MEDLINE; 1996 to 2003), Excerpta Medica (EMBASE; 1970 to 2003), Web of Science/Institute for Scientific Information (ISI; 1945 to 2003), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS; 1982 to 2003) and the Cochrane Library.

REVIEW METHODS

The medical subject headings used were "nitroprusside and pregnancy", "hypertension or eclampsia or preeclampsia" and "nitroprusside and pregnancy and hypertensive emergencies". The search was limited to humans and female gender, in all fields, publication types, languages and subsets. Articles were also identified by reviewing the references of articles and textbooks on hypertension and pregnancy.

RESULTS

The search located nine studies. The sum of all the publications yielded a total of 22 patients and 24 exposed fetuses (two pairs of twins). There were no randomized clinical trials and no prospective cohorts. All of the studies were observational in nature.

CONCLUSIONS

At present, there is insufficient evidence for definitive conclusions about any direct association between sodium nitroprusside use and fetal demise.

Managing Emergency Hypertension in Aortic Dissection and Aortic Aneurysm Surgery

From a disease that just a few decades ago carried an ominous prognosis, aortic dissection has become a highly treatable condition. Similar development has occurred in regard to the treatment of thoracic aortic aneurysms. Treatment options are medical, surgical, or endovascular. Aortic dissection always presents as a hypertensive emergency and requires parenteral antihypertensive agents to control blood pressure (BP) and prevent target organ damage. Diligent control of BP is of utmost importance in order to stop the progression of dissection with possible aortic branch malperfusion. Treatment for hypertensive emergency begins in the intensive care unit and continues during and after surgery. Improved surgical techniques as well as newer, safer agents that reduce BP to acceptable levels have reduced the risk of mortality and improved prognosis in the postoperative period. Nevertheless, mortality rates remain high, and successful management of aortic dissection and aortic aneurysm still poses a clinical challenge.

Nicardipine versus Nitroprusside Infusion as Antihypertensive Therapy in Hypertensive Emergencies

This prospective study compared the efficacy of nicardipine and nitroprusside for treating hypertensive emergencies by measuring haemodynamic indices and serum catecholamine levels. Patients admitted to the emergency department with a hypertensive crisis and acute pulmonary oedema received intravenous infusions of nitroprusside (starting dose 1 μg/kg per min, n = 20) or nicardipine (starting dose 3 μg/kg per min, n = 20). Both groups experienced significant declines in systolic and diastolic blood pressure after treatment, but there were no significant time-dependent differences between the groups. Heart rate decreased in the nicardipine group and increased in the nitroprusside group, but neither change was significant. Respiration rate decreased and capillary oxygen saturation rate increased after treatment in both groups. Adrenaline and noradrenaline levels decreased significantly after treatment in both groups; noradrenaline levels were significantly decreased in the nicardipine-treated group compared with the nitroprusside-treated group. Injectable nicardipine is easy to use and as effective as nitroprusside for treating hypertensive crisis with acute pulmonary oedema.

Tocolytic effects of intravenous nitroglycerin

Currently available tocolytic agents have shown partial or transient efficacy on uterine contractions delaying delivery for 24 or 48 h without reduction in perinatal morbidity and mortality. These facts led us to study a new tocolytic compound. A double-blind dose finding study of the nitroglycerin tocolytic effect during preterm labor was conducted using a continual reassessment method among six different doses (0.2-1.2 mg/h for 2 h) in pregnant women who were unresponsive, intolerant to salbutamol, or with a contraindication to this therapy. Twenty-five pregnant women were included. The probability of success in stopping uterine contractions reached, for the maximal dose (1.2 mg/h), only a 54% rate (95% CI: 29-79%). Twelve patients complained of headaches and 16 experienced a decrease in arterial blood pressure suggesting that it would not be safe to increase the dose in order to obtain a higher success rate. The present study suggests that nitroglycerin is not as effective as expected in controlling uterine contractions during severe preterm labor in patients where beta2 agonists cannot be used.

Severely increased blood pressure in the emergency department

Patients with severely increased blood pressure often present to the emergency department. Emergency physicians evaluate and treat hypertension in various contexts, ranging from the compliant patient with well-controlled blood pressure to the asymptomatic patient with increased blood pressure to the critically ill patient with increased blood pressure and acute target-organ deterioration. Despite extensive study and national guidelines for the assessment and treatment of chronically increased blood pressure, there is no clear consensus on the acute management of patients with severely increased blood pressure. In this article, we examine the broad spectrum of disease, from the asymptomatic to critically ill patient, and the dilemma it creates for the emergency physician in deciding how and when in the process to intervene.

Current concepts in the management of hypertensive crisis: emergencies and urgencies

Hypertensive emergencies and hypertensive urgencies represent a large percentage of major medical emergencies and have the potential of producing serious organ damage or death if not treated promptly and selectively. Several classifications of antihypertensive agents are discussed, with emphasis on selecting agents appropriate for patients' hypertension manifestations and comorbid situations. Epidemiology and evaluation of hypertension, as well as common pharmacokinetics of several common and new oral and parenteral antihypertensive agents, are described. Special nursing considerations of medication administration and gerontology concepts are included.

The diagnosis and management of hypertensive crises

Severe hypertension is a common clinical problem in the United States, encountered in various clinical settings. Although various terms have been applied to severe hypertension, such as hypertensive crises, emergencies, or urgencies, they are all characterized by acute elevations in BP that may be associated with end-organ damage (hypertensive crisis). The immediate reduction of BP is only required in patients with acute end-organ damage. Hypertension associated with cerebral infarction or intracerebral hemorrhage only rarely requires treatment. While nitroprusside is commonly used to treat severe hypertension, it is an extremely toxic drug that should only be used in rare circumstances. Furthermore, the short-acting calcium channel blocker nifedipine is associated with significant morbidity and should be avoided. Today, a wide range of pharmacologic alternatives are available to the practitioner to control severe hypertension. This article reviews some of the current concepts and common misconceptions in the management of patients with acutely elevated BP.

Diagnosis and management of hypertensive emergencies

It has been estimated that approximately 600,000 to 800,000 Americans will develop a hypertensive crisis (Calhoun and Oparil, 1990). Although such numbers represent only about 1% of the estimated 60 million Americans with hypertension, hypertensive crisis often constitutes a major medical emergency, necessitating a focused, assertive, and reasoned therapeutic intervention. When such patients are seen in the emergency department or in a physician's office with a critical elevation in blood pressure (BP), appropriate and efficacious management is essential to avoid catastrophic injury to vital target organs, including the central nervous system, the heart, and the kidneys. Delays in initiating effective therapy or, equally important, overzealous therapy leading to a too-rapid reduction in BP can produce severe complications involving these target organs. This article reviews the spectrum of clinical syndromes that comprise hypertensive emergencies, highlighting 2 to illustrate the complexities of clinical presentation and management. The newly advocated treatment guidelines based on the category of acute severe hypertension (including asymptomatic hypertensive urgencies) are also considered, as are therapeutic strategies utilizing currently available antihypertensive agents.

In vivo venodilator action of fenoldopam, a dopamine D(1)-receptor agonist

The effects of the dopamine D(1)-receptor agonist fenoldopam were compared with those of the D(2)-receptor agonist R(-)-propylnorapomorphine and vehicle on mean arterial pressure (MAP), mean circulatory filling pressure (MCFP, the driving force of venous return), arterial resistance (R(a)), venous resistance (R(v)), heart rate (HR) and cardiac output (CO) in groups of thiobutabarbitone-anaesthetized rats pre-treated with i.v. injection of mecamylamine (3.7 micromol kg(-1)) and continuously infused with noradrenaline (6.8 nmol kg(-1) min(-1)). The vehicle did not alter any haemodynamic variables. All doses of fenoldopam (0.5, 2 and 16 microgram kg(-1) min(-1)) reduced MAP, R(a) and R(v), and increased CO. At the highest dose, fenoldopam also increased HR and reduced MCFP. All doses of R(-)-propylnorapomorphine (0.5, 2 and 16 microgram kg(-1) min(-1)) increased MAP but did not significantly alter CO, R(v) and MCFP. Both R(a) and HR were increased by the highest dose of R(-)-propylnorapomorphine. Our results indicate that fenoldopam reduces MAP and MCFP, and markedly increases CO through reductions of arterial and venous resistances. The effects of fenoldopam in dilating arterial resistance and capacitance vessels were similar. In contrast, R(-)-propylnorapomorphine elevates MAP through an increase in arterial resistance but has minimal effects on CO, MCFP and venous resistance. Both drugs have a small direct, positive chronotropic action at the highest dose.

Hypertension in the elderly: don't treat too quickly!

In the asymptomatic patient without target organ damage who is seen with severely elevated BP, pseudohypertension is more often than not the cause. Rapid lowering of arterial pressure is unnecessary and even contraindicated. Nurses play an important role in the evaluation and the treatment of elderly patients with hypertension. Both research-based practice and thorough evaluation and monitoring are requisite for safe and effective treatment. Given the seriousness of the adverse effects and the lack of outcome data, the use of sublingual nifedipine capsules in hypertensive emergencies and pseudohypertension should be abandoned.