Pattern Of Hemodynamic Changes Research Articles

Changes in muscle blood flow after smoking a cigarette determined by a new noninvasive method.

In 9 healthy subjects the effect of smoking one cigarette (nicotine content 0.9 mg) on blood pressure, heart rate and total and muscle blood flow in the forearm was measured. Blood flow was measured by a new noninvasive plethysmographic method that simultaneously gives quantitative data about total and muscle blood flow. Smoking the cigarette did not significantly affect blood pressure or heart rate. Total blood flow in the forearm did not change but the flow to the muscle was increased and resistance in this vascular bed was decreased. The pattern of haemodynamic changes in the forearm indicates that epinephrine may be the mediator of the circulatory effects of nicotine.

Acute Hemodynamic Effects of Levothyroxine Loading in Critically Ill Hypothyroid Patients

To evaluate the acute cardiovascular effects of high-dose levothyroxine sodium therapy, the hemodynamic findings in eight critically ill hypothyroid patients treated with high-dose levothyroxine were compared with those in two critically ill hypothyroid and nine critically ill euthyroid patients not receiving this therapy. The initial cardiac index was significantly lower in the hypothyroid group; all other hemodynamic values were similar to those of the euthyroid patients. Following levothyroxine loading, the free thyroxine index increased to normal while the free triiodothyronine index was unchanged; all patients had a significant rise in cardiac index but no consistent changes in the other hemodynamic values. Cardiac index correlated positively with heart rate (three patients) and/or stroke volume index (six patients). Increases in stroke volume index correlated with decreases in systemic vascular resistance (five patients), but not with increases in pulmonary artery wedge pressure. No consistent patterns of hemodynamic changes were observed in the untreated hypothyroid or the euthyroid patients.