MSM 013 Assessing hypertension

“Nature tops the list of potent tranquilizers and stress reducers. The mere sound of moving water has been shown to lower blood pressure.”

-Patch Adams, M.D.

            Every year in the United States, more than 17 million people visit Emergency Departments with presenting complaints of hypertension.[1] These patients vary in age; however, many these patients are over the age of sixty-five. There are many different causes of hypertension that include lifestyle choices and genetics.

In a nutshell, hypertension can be caused by electrolyte imbalances, specifically pertaining to the kidneys inability to excrete equal amounts of sodium and potassium. These imbalances cause undue strain in the renal system and cause the blood pressure to elevate over time. These imbalances may exist in conjunction to, or independent of complications with the renin-angiotensin-aldosterone system. Angiotensin contributes to the diameter and patency of blood vessels, whereas aldosterone contributes to fluid balance and sodium levels in the body. An increase in aldosterone will cause a fluid imbalance in the patient, and will lead to hypertension. There are additional structural concerns in patients with hypertension that pertain to blood vessel structure and sympathetic nervous response as well.

There are times when patients presenting to EMS or the emergency department might see a patient with a presentation similar to the following:

“Patient is a 70-year-old Caucasian female with no specific complaint. Patient reports that she was at home and took her blood pressure with her home monitor, as she typically does once a week. The reported blood pressure was 160/100 and a heart rate of 98. EMS reports that the patient seemed anxious during their contact and report similar vital signs. Patient is presently resting comfortably in Room 10. Vital Signs: 172/104 HR: 110 RR: 22 SPO2: 98%RA.”

The first instinct of some EMS providers may be to see the patient’s systolic blood pressure and focus on that as the medical emergency. It is important to remember that this patient has no presenting complaint. The standard front-line assessment tools of cardiac monitoring, 12-lead EKG, blood glucose testing, and stroke assessments may be appropriate, but they do not necessarily address the immediate health concerns of the patient.

On a long enough timeline hypertension, especially if it is poorly controlled by medication can cause a compendium of health problems including left ventricular hypertrophy, MI and stroke. Luckily, stroke and MI are two arenas in which EMS excels. Yet we still tend to fall short when we assess patients with an exclusive presentation of hypertension. When addressing these patients, we must ask ourselves what might be the underlying condition, if indeed there is one. Patients with no reported history of hypertension may simply be poor historians, or they may not seek the care of a primary physician often enough to carry a diagnosis if hypertension. Additionally, if a patient is poor historian, it may become the responsibility of the EMS provider to extrapolate part of the patient’s history by reviewing a list of medications that the patient takes. Specifically, if a patient takes a beta-blocker such as Lopressor (metoprolol) or Coreg (carvedilol) the patient may have a history of hypertension. Often it may be reported that a patient “used to have” a history of hypertension, but the patient may feel that they no longer have the disease since they are medicated for it.

The patient’s history notwithstanding, the EMS provider must recognize the different clinical presentations of simple hypertension, symptomatic hypertension, and hypertensive crisis. Simple hypertension is consistent with the patient mentioned above. This patient has no specific complaint, or may complain of generalized malaise, and happens to have an elevated blood pressure in addition to this presentation. When assessing these patients, keep in mind that approximately one-third of adults in the United States have some degree of hypertension[2] and the presence of EMS at the patient’s home may independently raise the blood pressure transiently. Having 9-1-1 called to your house and having strangers evaluate your health can be stressful, after all.

The difference between symptomatic hypertension and a hypertensive crisis (or hypertensive emergency) may seem to be semantic to the EMS provider, but the difference in important. Severely elevated blood pressure is defined as a systolic blood pressure equal to or greater than 180 mmHg, and a diastolic blood pressure equal to or greater than 110 mmHg. Again, these vital signs alone do not denote the emergency. The patient may be hypertensive and the undue stress of the presenting emergency may transiently raise their blood pressure over these limits. However, if a patient presents symptoms such as a headache, blurry or double vision, or a gait abnormality, EMS should hold a high suspicion for a hypertensive emergency. The clinical separation of severe hypertension and a hypertensive crisis is end organ failure or dysfunction. End organ dysfunction may be difficult for an EMS provider to obtain, but if during the assessment, the patient mentions anuria (absent urination), the provider should hold a high index of suspicion for a hypertensive crisis.

Treatment of hypertensive crisis can vary from project to project depending on the availability of pharmacologic agents that the providers have at their disposal. However, in general treatment should be aimed at a guided reduction of blood pressure and relief of symptoms. Guided reduction of blood pressure refers to not dropping the patient’s blood pressure precipitously or quickly. Drugs like labetalol work well in this setting. Labetalol is a combination drug that has alpha-1 and nonselective beta adrenergic effects. The advantage of this combination is that labetalol can lower blood pressure at small doses (20mg every 10 minutes to desired effect, followed by a maintenance drip), and while the drug reduces systemic vascular resistance, the alpha effect of the drug allows for maintenance of peripheral, cerebral, and renal blood flow. A drug like Lopressor may reduce blood pressure at a dose of 5mg, however the beta-selective effects may require pharmacologic augmentation of the blood pressure if the systolic pressure is dropped too low.

There are other agents that may be employed for the management of hypertension such a nicardipine, nitroglycerin, esmolol, and nitroprusside, however these drugs are seldom seen in the EMS arena and more often carried by critical care services. These drugs and their indications will be addressed in a separate post. Overall, the management of hypertension in the pre-hospital environment can be summarized by aiming to reduce symptoms and otherwise supportive care. As always, make sure to thoroughly assess your patients and obtain as precise a medical history as possible. The history taking can make all the difference.

[1] https://www.cdc.gov/nchs/data/ahcd/nhamcs_emergency/2013_ed_web_tables.pdf

[2] http://www.aafp.org/afp/2010/0215/p470.html