Object: Because critically ill patients often have peripheral circulatory disturbance, it is very important to evaluate the status of peripheral circulation as well as cardiac function. We evaluted peripheral circulation in critically ill patients by pulsed Doppler ultrasonography.
Methods: The subjects were 5 critically ill patients with the cold extremities. All of them were on mechanical ventilation in the intensive care unit. We measured the blood flow velocity of the radial artery before and during reactive hyperemia, which was induced by a 3-minute occlusion of the brachial artery by a tourniquet. Normal controls used for comparison were 10 healthy volunteers.
Results: Skin temperature of the examined upper extremity in the patient group was significantly lower than that in the control group (26.1 ± 2.4 oC versus 33.8 ± 1.6 oC, p<0.0001). Before reactive hyperemia, the mean blood flow velocity of the radial artery in the patient group was significantly lower than that in the control group (0.05 ± 0.03 m/sec versus 0.27 ± 0.11 m/sec, p=0.0011). Pulsatility index and resistance index in the patient group were significantlly higher than those in the control group (9.3 ± 4.4 versus 3.1 ± 1.7, 1.4 ± 0.3 versus 0.9 ± 0.3, respectively). The baseline blood flow in all of the patient group had the reverse flow. The mean velocity of the reactive hyperemic blood flow in the patient group was significantly increased, compated witth that at baseline (0.05 ± 0.03 m/sec to 0.21 ± 0.11 m/sec, p<0.05), while pulsatility index and resistance index were significantly decreased. The increase rate of the mean flow velocity in reactive hyperemia was similar for both groups.
Conclusion: The peripheral blood flow in criticallly ill patients with the cold extremities is significantly decreased, however the peripheral vascular responsiveness is maintained.