Cardiovascular System

When given orally in sedative or hypnotic doses, the barbiturates do not produce significant overt cardiovascular effects except for a slight decrease in blood pressure and heart rate such as occurs in normal sleep. Cardiovascular reflexes are obtunded by partial inhibition of ganglionic transmission; this is most evident in patients with congestive heart failure or hypovolemic shock, whose reflexes already are operating maximally and in whom barbiturates can cause an exaggerated fall in blood pressure. Because barbiturates also impair reflex cardiovascular adjustments to inflation of the lung, positive-pressure respiration should be used cautiously and only when necessary to maintain adequate pulmonary ventilation in patients who are anesthetized or intoxicated with a barbiturate.

Intravenous anesthesia with barbiturates can increase the incidence of ventricular arrhythmias, especially when epinephrine and halothane also are present. Direct depression of cardiac contractility occurs only when doses several times those required to cause anesthesia are administered.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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