Hypertension Overview and Causes

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Questions and Answers

What is the definition of hypertension?

A long-term condition with blood pressure elevated at or above 140 mmHg SBP and 90 mmHg DBP. (correct)

An acute medical emergency caused by stress.

A temporary increase in blood pressure due to physical activity.

A chronic condition with normal blood pressure levels.

Which of the following is NOT a mechanism that maintains normal blood pressure?

Activities of vascular endothelium

Activities of sympathetic nervous system

Activities of the digestive system (correct)

Activities of renal system

What percentage of hypertension cases is classified as secondary hypertension?

1-2%

15-20%

25-30%

5-10% (correct)

Which lifestyle change is recommended for managing hypertension?

Regular physical activity Signup and view all the answers

Which of the following is a common cause of primary hypertension?

Unhealthy eating patterns Signup and view all the answers

What is a symptom that can occur with very high blood pressure?

Severe headaches Signup and view all the answers

What is the role of antihypertensive drugs in the treatment of hypertension?

They are prescribed when lifestyle changes are insufficient to control blood pressure. Signup and view all the answers

Which of the following is NOT a symptom of hypertension?

Chronic fatigue not related to sleep Signup and view all the answers

Which class of medication prevents calcium from entering muscle cells of the heart and blood vessels?

Calcium channel blockers Signup and view all the answers

What is one of the main goals of preoperative investigations for patients with hypertension?

To identify and assess comorbid conditions Signup and view all the answers

Which of the following medication types should be continued in the perioperative period for patients with hypertension?

Beta-blockers Signup and view all the answers

What is the significance of a preoperative blood pressure reading of less than 180/100 mmHg?

It does not necessitate surgery postponement without other comorbidities Signup and view all the answers

Which medication is often prescribed for patients with hypertension, particularly in the perioperative period?

Statins Signup and view all the answers

Which class of medication helps to widen blood vessels and increase urine output by the kidneys?

Diuretics Signup and view all the answers

Which method is recommended for managing intraoperative hypotension in patients undergoing non-cardiac surgery?

Immediate fluid resuscitation Signup and view all the answers

What risk is greatly increased by severe hypertension (≥180/110 mmHg) before surgery?

Risk of surgical complications Signup and view all the answers

What is a potential consequence of intraoperative hypotension (IOH)?

Increased risk of renal failure Signup and view all the answers

Which patient demographic is correlated with a higher risk of IOH?

Older male patients Signup and view all the answers

What is suggested for patients who are nil by mouth after surgery?

Alternative routes for antihypertensive administration should be considered Signup and view all the answers

What is the recommended approach regarding long-term antihypertensives in the pre-anesthesia period?

Long-term antihypertensives should not be discontinued Signup and view all the answers

Which factor is primarily responsible for postoperative complications related to hypertension?

Preoperative diagnosis and evaluation Signup and view all the answers

What type of hypotension occurs after the induction of general anesthesia but before surgical incision?

Postinduction hypotension Signup and view all the answers

Why is supplementary oxygen recommended for high-risk patients post-anesthesia?

To reduce the risk of hypoxia and ischaemic episodes Signup and view all the answers

Which factor does NOT contribute to intraoperative hypotension (IOH)?

Higher pre-induction systolic arterial pressure Signup and view all the answers

What is the initial step in managing a 65-year-old man with a pre-assessment blood pressure of 190/100 who is scheduled for total knee replacement?

Standard anaesthetic assessment Signup and view all the answers

Which antihypertensive drug is recommended as a first-line treatment for elderly patients?

Thiazides Signup and view all the answers

In the context of hypertensive patients undergoing surgery, which anesthetic drug should be avoided during induction?

Ketamine Signup and view all the answers

What action should be taken if a patient's hypertension persists after assessment on the day of elective surgery?

Postpone surgery and initiate thiazide diuretic treatment Signup and view all the answers

What is a common side effect associated with the use of ACE inhibitors in treating hypertension?

100% hypertension Signup and view all the answers

Which of the following medications is recommended for long-term management of hypertension?

Calcium channel blockers Signup and view all the answers

During postoperative recovery, why is pain management particularly important for hypertensive patients?

Pain often leads to increased blood pressure Signup and view all the answers

Which class of drugs is typically avoided in first-line treatment due to side effects like lethargy and malaise?

Beta blockers Signup and view all the answers

Study Notes

Definition

Hypertension, or high blood pressure (HBP), is when blood pressure in arteries is consistently elevated.
Systolic blood pressure (SBP) of 140 mmHg or higher AND diastolic blood pressure (DBP) of 90 mmHg or higher indicates hypertension.

Etiology

Primary Hypertension: Elevated blood pressure without a known cause, accounting for the majority of cases.
Secondary Hypertension: Elevated blood pressure with a specific cause. Makes up 5-10% of all cases.

Pathophysiology

Normal blood pressure is maintained by the interplay of four mechanisms:
- Sympathetic nervous system
- Vascular endothelium
- Renal system
- Endocrine system

Causes of Primary Hypertension

Unhealthy eating habits (high sodium intake).
Lack of physical activity.
Excessive alcohol consumption.

Causes of Secondary Hypertension

Certain medications (immunosuppressants, NSAIDs).
Kidney disease.
Obstructive sleep apnea.
Renal vascular diseases.
Tobacco use (smoking, vaping, smokeless tobacco).

Signs and Symptoms

Most people with hypertension experience no symptoms.
Severe hypertension can lead to:
- Severe headaches.
- Chest pain.
- Dizziness.
- Difficulty breathing.
- Nausea and vomiting.
- Vision changes.
- Anxiety.
- Confusion.
- Nosebleeds.
- Abnormal heart rhythm.

Management and Treatment

Lifestyle modifications can help lower blood pressure:
- Heart-healthy diet low in salt.
- Regular physical activity.
- Maintaining a healthy weight or losing weight.
- Limiting alcohol intake.
- Quitting smoking.
- Adequate sleep (7-9 hours).
Medications are often needed in addition to lifestyle changes.
The choice of medication depends on individual health status and severity of hypertension.
Two or more medications are frequently more effective than a single drug.
Finding the optimal medication or combination takes time.
Factors to consider when deciding if medication is necessary:
- Blood pressure readings.
- Risk of developing complications (heart attacks, strokes).

Antihypertensive Medications

Angiotensin-converting enzyme (ACE) inhibitors: Help prevent blood vessel narrowing.
Angiotensin II receptor blockers: Also prevent blood vessel narrowing.
Calcium channel blockers: Block calcium entry into heart and blood vessel muscle cells, promoting relaxation and widening of blood vessels.
Diuretics: Increase urine production, removing excess fluid and salt, leading to wider blood vessels.
- Potassium-sparing diuretics
- Loop diuretics
- Thiazide diuretics
- Thiazide-type diuretics
Direct vasodilators: Directly dilate blood vessels.

Preoperative Hypertension Management

Assessment: Thorough assessment of hypertensive surgical patients, including accurate blood pressure measurements.
Preoperative Investigations:
- Serum electrolytes.
- Creatinine.
- Estimated glomerular filtration rate.
- Cholesterol.
- 12-lead electrocardiogram.
- Urinalysis.
Surgery should not be delayed solely due to pre-operative blood pressure readings below 180/100 mmHg unless other issues are present.
Severe Hypertension (≥180/110 mmHg) can increase surgical risks, requiring sufficient blood pressure control before surgery.
Oral hypertensive medications should be continued pre- and post-surgery.
Sympathetic blockers, such as beta-blockers, must be continued.
Statins are often prescribed for hypertensive patients and should be continued perioperatively.
Aspirin is recommended for low-risk patients undergoing non-cardiac surgery.

Intraoperative Hypotension (IOH)

Low arterial blood pressure during surgery is frequent in non-cardiac surgery under general anesthesia.
Cause is multifactorial and is associated with postoperative complications:
- Acute kidney injury.
- Myocardial injury.
- Death.
IOH is a modifiable risk factor for postoperative complications.
No universal definition for IOH.
IOH exists beyond surgery, with one-third of perioperative hypotensive episodes occurring post-anesthesia induction but before surgical incision.

Risk Factors for IOH

Older age.
Male sex.
Lower pre-induction systolic blood pressure.
General anesthesia with propofol.

Postoperative Care

Close monitoring after anesthesia to minimize and address postoperative complications.
Continue antihypertensive medications after surgery, considering alternative administration routes for NPO (nil by mouth) patients.
Close monitoring of patients with severe hypertension, alerting ward and anesthesia staff if management becomes challenging or uncontrolled.
Supplementary oxygen for high-risk patients to prevent hypoxia and reduce ischemic episodes.
Promote ongoing prevention of hypertensive triggers on the ward.

Conclusion

Hypertensive patients are at increased risk of complications during anesthesia, including hypertensive crisis, hypotension, and worsened end-organ damage.
Preoperative evaluation is crucial: Assess comorbidities and medications.
Long-term antihypertensives are generally recommended to be continued, with recent studies discouraging discontinuation.
Thorough pre-operative evaluation is essential to prevent per- and postoperative complications.

Summary

Definition and normal blood pressure.
Etiology (primary and secondary hypertension) and pathophysiology (blood pressure regulation).
Stages of hypertension.
Causes of hypertension.
Signs and symptoms of hypertension.
Management and treatment, including lifestyle changes and antihypertensive medications.
Antihypertensive drug classes and key considerations.
Peri-operative care for hypertensive patients (pre-operative assessment and investigation, intra-operative management, postoperative care).

Self Assessment

A 65-year-old patient is scheduled for a total knee replacement. His pre-assessment blood pressure is 190/100.
- Perform a standard anesthetic assessment.
- Gather history of hypertension and medication use.
- Determine if the blood pressure reading is a one-off or persistent.
- Check for evidence of end-organ damage.
- Repeat blood pressure measurements in a relaxed environment.
- Obtain an ECG.
- Order routine blood work.
- If the hypertension is new and persistent at this level, consider:
- Postponing surgery.
- Initiating a thiazide diuretic prior to rescheduling.
- Consulting with the patient's GP.
Commonly used antihypertensive medications:
- Long-term: Thiazide diuretics, ACE inhibitors, calcium channel blockers, beta-blockers.
- Acute: Beta-blockers, calcium channel blockers, alpha-2 blockers, vasodilators.
A 77-year-old patient presents in recovery with a blood pressure of 210/110 after a laparoscopic cholecystectomy.
This indicates severe postoperative hypertension.
Evaluate for potential causes: - Underlying medical conditions. - Surgical stress. - Medication interactions. - Pain.

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Description

This quiz covers the definition, etiology, and pathophysiology of hypertension, including primary and secondary forms. Participants will test their knowledge on the causes and mechanisms that maintain normal blood pressure. Understand the distinctions between primary and secondary hypertension and their respective triggers.