Cardiovascular system intravenous

Midazolam Midazolam is water-soluble and can be administered intravenously, intramuscularly,13 buccally,14,15 and nasally.16,17 At physiologic pH, it becomes more lipophilic and can diffuse into the CNS. Compared to diazepam and lorazepam, it has fewer effects on the respiratory and cardiovascular systems. Its short half-life requires that it be re-dosed... 

The existing data indicate that, in humans, respiratory and hepatic effects result from inhalation exposure and that the liver, hematopoietic system and cardiovascular system are the target organs following intravenous injection of Thorotrast. Studies in animals have not reported effects in these... 

Another study of the effects of I on the cardiovascular systemic concluded that, in dogs anesthetized with sodium pentobarbital, the response of blood pressure to intravenous administration of I is a resultant of two separate effects a direct myocardial stimulation that was stopped with dichlorolsoproterenol and a stimulation of vascular smooth muscle that results in a slight increase in renal arterial pressure and a slight decrease in renal arterial flow. Neither atropine nor dichlorolsoproterenol affected these vascular effects. Injections of 1 into a jugular vein or a renal artery had no consistent effect on catecholamine concentrations in plasma taken from a femoral artery or a renal vein. In seven experiments in which I at 21-35 mg/kg was injected into a jugular vein, the mean blood pressure increased from 176/125 + 22/11... 

The use of propofol is associated with a feeling of well-being during early recovery and nausea and vomiting is less common in the postoperative period than with some other intravenous agents. Subanaesthetic doses of propofol have been used to treat early postoperative nausea and emesis. Cardiovascular system... 

At doses up to those causing hypnosis, no significant effects on the cardiovascular system are observed in healthy patients. However, in hypovolemic states, heart failure, and other diseases that impair cardiovascular function, normal doses of sedative-hypnotics may cause cardiovascular depression, probably as a result of actions on the medullary vasomotor centers. At toxic doses, myocardial contractility and vascular tone may both be depressed by central and peripheral effects, leading to circulatory collapse. Respiratory and cardiovascular effects are more marked when sedative-hypnotics are given intravenously. 

Marijuana has several effects on the cardiovascular system, and can increase resting heart rate and supine blood pressure and cause postural hypotension. It is associated with an increase in myocardial oxygen demand and a decrease in oxygen supply. Peripheral vasodilatation, with increased blood flow, orthostatic hypotension, and tachycardia, can occur with normal recreational doses of cannabis. High doses of THC taken intravenously have often been associated with ventricular extra beats, a shortened PR interval, and reduced T wave amplitude, to which tolerance readily develops and which are reversible on withdrawal. While the other cardiovascular effects tend to decrease in chronic smokers, the degree of tachycardia continues to be exaggerated with exercise, as shown by bicycle ergometry. 

Reduction of portal pressure. Vasopressin (anti-duiretic hormone, see p. 711), in addition to its action on the renal collecting ducts (through receptors), constricts smooth muscle (Vj receptors) in the cardiovascular system (hence its name), and particularly in splanchnic blood vessels, so reducing blood flow in the portal venous system. Unfortunately, coronary vasoconstriction can also occur, and treatment has to be withdrawn from 20% of patients because of myocardial ischaemia. Glyceryl trinitrate (transdermally, sublingually, or intravenously) reduces the cardiac risk and, advantageously, further reduces portal venous resistance and pressure. 

The cardiovascular system is more resistant to the toxic effects of local anesthetics than the nervous system. Mild circulatory depression can precede nervous system toxicity, but seizures are more likely to occur before circulatory collapse. The intravenous dose of lidocaine required to produce cardiovascular coUapse is seven times that which causes seizures. The safety margin for racemic bupivacaine is much lower. The stereospecific levorotatory isomers levobupivacaine and ropivacaine are less cardiotoxic, and have a higher safety margin than bupivacaine, but not lidocaine in the case of ropivacaine this may be at the expense of reduced anesthetic potency (14,15). Toxicity from anesthetic combinations is additive. 

Although intravenous infusion of epinephrine has pronounced effects on the cardiovascular system, iLs use in the treatment of heart block or circulatory collapse is limited because of its tendency to induce cardiac arrhythmia.s. It increases systolic pressure by increasing cardiac output, and it lowers diastolic pressure by causing an overall dccrea-c in peripheral resistance the net result is little change in mean hlood pressure. 

The actions of norepinephrine and epinephrine on the cardiovascular system may be quite different when both drugs are administered in small doses (0.1 to 4.0 pg/kg/min in a slow intravenous infusion), but are essentially the same when given in large doses. 

The toxic action of cocaine can be combated by barbital curatively (143) or preventively (144), but this is scarcely seen to be effective in the clinic (145). Steinhaus and Tatum (146), however, stated that pentobarbital in doses of 15 mg./kg., when given intravenously, affords protection against 100 mg./kg. of cocaine injected subcutaneously. The toxicity of cocaine injected into the venous system depends upon the speed with which it is introduced into the organism. If this speed is great the cardiovascular system is affected before the respiration, but if it is slow the contrary is seen, as is the case for subcutaneous injections. 

Denson DD, Behbehani MM, Gregg RV. Enantiomer-specific effects of an intravenously administered arrhythmogenic dose of bupivacaine on neurons of the nucleus tractus solitarius and the cardiovascular system in the anesthetized rat. Reg Anesth 1992 17 311-316. 

Inotropy was seen in dogs given a single intravenous dose of 1 mg/kg bw. An NOEL for inotropy was not identified. No adverse effects on the cardiovascular system were found in a two year dog oral toxicity study, although the routine tests performed in the study would not be expected to detect inotropy. 

---