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Hypertension and hypotension

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Hypertension

Definition

Hypertension is characterised by a persistent pathological increase in arterial blood pressure.
(The Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7), 2003)

Blood pressure category (mm Hg)   systolic     diastolic
Normal < 120 and < 80
Pre-hypertension

120-139 or 80-90
Hypertension stage I 140-159   and/or   90-99
Hypertension stage II   ≥160 and/or ≥100

At least 20% of patients with hypertension do not know that their blood pressure is elevated.
In approximately 90% of the cases, no definitive cause of hypertension can be determined by modern diagnostic techniques.

Symptoms of hypertension

Hypertension symptoms are unspecific:
  • Headache, especially in the early morning
  • Epistaxis
  • Visual disturbances
  • Vertigo
  • Tinnitus
  • Nausea
  • Fatigue
  • Heart failure

The body reacts with a hypertrophy of blood vessels which favours atherosclerosis.
The cardiac muscle pumps against an increased resistance which also results in hypertrophy.
Consequences of the vascular damage to the heart are congestive heart failure, CHD and arrhythmias.
Vascular damage in other organs results in damage to the eyes, kidneys, etc.

Pursuant to the recommendations of the Joint National Committee on the Prevention, Detection and Treatment of High Blood Pressure, the term used in the past (hypertensive crisis) - which was defined as dangerous elevation of blood pressure with associated symptoms - is no longer used.
Today we distinguish between the terms "hypertensive emergency" and "hypertensive urgency" (Joint National Committee 2003).

Hypertensive urgency

Critical elevation of blood pressure (e.g. > 230/130mm/Hg) without symptoms of acute organ damage.
The absolute blood pressure height plays a subordinated role.
General clinical signs are rather unspecific.

Clinical symptoms of hypertensive urgency include the following:
  • Headache
  • Nosebleed
  • Disturbed vision
  • Vertigo
  • Tinnitus
  • Nausea
Treatment of hypertensive urgency
  • In hypertensive urgency, it is sufficient to discontinue dental treatment and control blood pressure after 30 minutes rest and lower it within 24 hours. Do not intent quick lowering of the blood pressure since the body's auto-regulatory mechanisms are changed and quick lowering may result in insufficient blood supply to the brain, the kidneys and the eyes.
  • Bring the patient in a sitting position.
  • Oxygen administration 4-6 L/min
  • Consult the patient's primary care physician and refer to an emergency department, if necessary.

Hypertensive emergency

Hypertensive emergency is defined as a dangerous increase in blood pressure associated with acute organ damage.
Here, the absolute blood pressure is not the decisive criterion but the re-occurrence or worsening of cerebral, cardiac or vascular life-threatening organ damage.
The general clinical signs are rather unspecific.

Clinical symptoms of hypertensive emergency may be
  • Nausea
  • Headache
  • Vertigo
  • Epistaxis
  • Palpitations
  • Angina pectoris
  • Dyspnoea
  • Neurological deficits (paraesthesia, paresis)
  • Disturbances of consciousness or even coma.


Cerebral complications
  • Hypertensive encephalopathy with a risk of stroke
  • Development of a cerebral oedema
Cardiac complications
  • acute left ventricular failure with pulmonary oedema
    The reason for this is a peripherally increased resistance (afterload)
  • Acute coronary syndromes (such as angina pectoris, myocardial infarction)
    The cardiac muscle works against high pressure which results in an increased oxygen consumption of the heart; at the same time, the high tension of the muscle walls makes the filling of the coronary arteries more difficult.


Treatment of hypertensive emergency

In case of hypertensive emergency the blood pressure should be decreased appropiately and the inpatient admission under monitoring should take place immediately evidence.de Hypertonie-Therapie.

Preparations of first choice:
  • Sublingual nitroglycerin
    Dosage: Have the patient chew 1 capsule or administer 2 puffs of the spray
    One capsule contains 0.8 mg, one puff 0.4 mg nitroglycerin.
    Nifedipin sublingual should not be used because of the danger of pronounced reflex tachycardias and a too rapid blood pressure lowering (Chest et Marik 2001)
  • Bring the patient in a sitting position
  • Oxygen administration 4-6 L/min
  • At the same time, call for emergency assistance.

Risk during dental treatment

An additional increase in blood pressure caused by treatment should be kept low

Risk reduction

  1. The psychic and physical strain on the patient should be reduced to a minimum.
  2. Hypertensive patients should rather be treated in the morning, not in the afternoon; the duration of the session should not be too long, if possible.
  3. Slow positional changes of hypertensive patients
    A possible adverse effect of many anti-hypertensive substances is orthostatic hypotension; therefore, the chair should be slowly brought to an upright position at the end of treatment session, and the patients should be supported when they get up until they have safely regained their balance.
  4. Pre-medication
    Very anxious patients may recieve low-dose diazepam (5mg) or oxazepam (30mg) an hour before treatment, and additionally the night before, if required.
  5. Use of an additional vasoconstrictor in local anaesthesia
    Higher quantities of a vasoconstrictor, or its accidental intravasal injection, can cause an increase in blood pressure within a short period of time.
    However, a strain-induced or pain-induced heavy increase in endogenous adrenaline release can exceed the little quantities of exogeneous adrenaline administered during dental treatment by far (Little 2000).
    Therefore, the advantages of local anaesthesia with a vasoconstrictor outweigh the supposed or potential risks and disadvantages.
    If local anaesthetics containing adrenaline are used, the amount of added adrenalin should be as low as possible (1:200,000). For a healthy adult, the maximum dose of adrenaline as a vasoconstrictor is 200 microgram; however, for patients with cardiovascular diseases, it is only up to 40 microgram (8mL of a solution 1:200,000). 22.5 microgram adrenaline, added to a local anaesthetic, were tolerated well by patients with cardiovascular diseases of various degrees of severity (Niwa. 2001).
  6. No local administration of vasoconstrictors
    Vasoconstrictors, however, should not be used in hypertensive patients for local haemostasis, neither should adrenaline-containing retraction cords be used.

Hypotension

Definitions

Chronic arterial hypotension
Systolic blood pressure < 100 mmHg.

Orthostatic hypotension
This occurs with impaired blood pressure regulation.
Typically, there are no complaints in a lying position.
Symptoms emerge only with a positional change, or when the patient sits upright.
While in a standing position, the patient experiences deranged blood pressure regulation leads to a fall in systolic blood pressure of at least 20 mm Hg within 3 minutes after getting up.
Venous blood is congested in the lower extremities.

Symptoms

  • Vertigo
  • Dizziness
  • visual blurring or flimmer before the eyes
  • Headache
  • Syncope possible
Consecutively:
  • Tachycardia
  • Paleness
  • Cold extremities
  • Sweating

Therapy of orthostatic syncope (fainting)

  • Lay the patient down
  • Elevate the patient's legs
  • Open windows (fresh air)
  • Etelifrin (e.g. Effortil®), an α- and β-adrenergic agonist
    Contraindications: arrhytmias, coronary heart disease, among others


sources

  • Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure (2003)   The seventh report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood press
  • Little JW (2000)   The impact on dentistry of recent advances in the management of hypertension   Oral Surg Oral Med Oral Pathol Oral Radiol Endod 90:591-9
  • Niwa H, Sugimura M, Satoh Y, Tanimoto A (2001)   Cardiovascular response to epinephrine-containing local anesthesia in patients with cardiovascular disease   Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001 92:6
  • Varon J, Marik PE (2001)   The diagnosis and management of hypertensive crises.    Chest 118:214-27