Hypotension
Dopamine is recommended for the correction of haemodynamic imbalance present in-
- Acute hypotension or shock associated with myocardial infarction, endotoxic septicaemia, trauma and renal failure.
- As an adjunct after open heart surgery, where there is persistent hypotension after correction of hypovolaemia.
- In chronic cardiac decompensation as in congestive failure.
Hypovolaemia should be corrected where necessary prior to treatment with dopamine hydrochloride. If a disproportionate rise in diastolic blood pressure (i.e. a marked decrease in pulse pressure) is observed, the infusion rate should be decreased and the patients observed carefully for further evidence of predominant vasoconstriction activity, unless such effect is desired. Dopamine hydrochloride infusion should be withdrawn gradually, to avoid unnecessary hypotension. Patients with a history of peripheral vascular disease (e.g. atherosclerosis, arterial embolism, Raynaud’s disease, cold injury, diabetic endarteritis and Buerger’s disease) should be closely monitored for any changes in color or temperature of the skin in the extremities. If ischemia occurs and is thought to be the result of vasoconstriction, the benefits of continued dopamine hydrochloride infusion should be weighed against the risk of possible necrosis. These changes may be reversed by either decreasing the rate or discontinuing the infusion. Dopamine hydrochloride in 5% dextrose solution should be infused into a large vein whenever possible to prevent the possibility of infiltration of perivascular tissue adjacent to the infusion site. Extravasations may cause necrosis and sloughing of the surrounding tissue. Ischaemia can be reversed by infiltration of the affected area with 10-15ml of saline containing 5 to 10mg Phentolamine mesylate. Dopamine hydrochloride should be used with extreme caution in patients inhaling cyclopropane or halogenated hydrocarbon anaesthetics due to the arterial arrhythmogenic potential. Dextrose solutions should be used with caution in patients with known subclinical or over diabetes mellitus.