Controlled Hypotension Flashcards
What is ‘controlled hypotension’?
The deliberate reduction in systemic blood pressure in order to
reduce blood loss
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 958.
What is traditionally regarded as the lowest mean
arterial pressure allowed when performing controlled
hypotension?
Although the actual number designated as the lowest allowable
pressure is determined on patient history and clinical status, the
generally accepted lowest value is 60 mmHg.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 959
What criteria should the anesthetist monitor in order
to ensure that the patient is perfusing tissues
adequately during controlled hypotension?
The urine output, arterial blood gases, and measures of cardiac
and cerebral perfusion pressure should be monitored and
maintained at normal levels during controlled hypotension.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 959.
What is the chief anesthetic concern when inducing
controlled hypotension in patients with chronic
hypertension?
Because patients with chronic hypertension typically require a
higher mean arterial pressure in order to maintain adequate
perfusion of vital organs. Controlled hypotension may place the
patient at risk for ischemia if the pressure is lower than the
patient can safely tolerate.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 959.
What are the advantages and disadvantages of
using fenoldapam for controlled hypotension?
Despite the decrease in arterial pressure, fenoldapam markedly
increases renal blood flow, urinary flow rate, urinary sodium
extraction, and creatinine clearance. It can produce tachycardia
and increases in intraocular pressure and should be used with
caution in patients with glaucoma.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 261.
What are the advantages and disadvantages of
using sodium nitroprusside to induce controlled
hypotension?
Sodium nitroprusside preserves cardiac output well, but can
result in reflex tachycardia, rebound hypertension, pulmonary
shunting, and carries the risk of cyanide toxicity.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 959.
What are the advantages and disadvantages of
using nitroglycerin to induce controlled hypotension?
Nitroglycerin preserves cardiac perfusion well, but can increase
intracranial pressure.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 959.
What are the advantages and disadvantages of
using esmolol to induce controlled hypotension?
It is useful for treating tachycardia, but can potentially result in
significant myocardial depression.
Nagelhout JJ, Plaus KL. Nurse Anesthesia. 5th ed. St. Louis,
MO: Elsevier Saunders Company; 2014: 959.
Which would be more suitable for producing
controlled hypotension, hydralazine or sodium
nitroprusside? Why?
Although numerous agents such as calcium channel blockers,
volatile agents, and hydralazine are acceptable for producing
controlled hypotension, the rapid onset and short duration of
action of sodium nitroprusside and nitroglycerin make them
most suitable for controlled hypotensive techniques.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 261.
What are the relative contraindications to performing
controlled hypotension?
Relative contraindications to performing controlled hypotension
include severe anemia, cardiovascular and cerebrovascular
disease, renal or hepatic insufficiency, uncontrolled glaucoma,
and hypovolemia. Chronic hypertension is not a relative
contraindication to controlled hypotension, but it warrants closer
monitoring of blood pressure. Because the alteration of
autoregulation of cerebral blood flow in chronically hypertensive
individuals, the mean arterial blood pressure should not be
lowered more than 20-30% below baseline.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 262.
