[Prospective study on the influence of dobutamine on blood perfusion in free flap repair of diabetic foot wounds].

Objective: To investigate the influence of clinical administration of dobutamine on blood perfusion in free flap repair of diabetic foot wounds. Methods: A prospective self-controlled study was conducted. From January to November 2022, 20 patients with diabetic foot who met the inclusion criteria were hospitalized in the Department of Burns and Plastic Surgery of Affiliated Hospital of Zunyi Medical University, including 9 males and 11 females, aged from 44 to 75 years, with the foot wounds area ranging from 5 cm×4 cm to 20 cm×10 cm, which were repaired by free anterolateral thigh flaps. Heart rate (HR) and mean arterial pressure (MAP) were recorded before anesthesia induction, 10 minutes after vascular recanalization, when the target blood pressure (i.e., MAP being 6-10 mmHg (1 mmHg=0.133 kPa) higher than that before anesthesia induction) was reached after infusion of dobutamine, and 10 minutes after tracheal catheter removal. Additionally, indocyanine green, a contrast agent, was injected intravenously at 10 minutes after vascular recanalization and when the target blood pressure was reached after infusion of dobutamine to assess flap blood perfusion using infrared imager, and the area ratio of flaps with hyperperfusion and hypoperfusion was calculated. Other recorded variables included flap harvesting area, surgical duration, total fluid infusion amount, infusion dose and total usage of dobutamine, intraoperative adverse events, postoperative flap complications, and follow-up outcomes. Data were statistically analyzed with paired sample t test, analysis of variance for repeated measurement, Bonferroni method, and generalized estimating equation. Results: Compared with those before anesthesia induction, HR and MAP of patients were significantly decreased at 10 minutes after vascular recanalization (P<0.05), while HR and MAP of patients were significantly increased when the target blood pressure was reached after infusion of dobutamine (P<0.05). Compared with those at 10 minutes after vascular recanalization, HR and MAP of patients were significantly increased when the target blood pressure was reached after infusion of dobutamine and at 10 minutes after tracheal catheter removal (P<0.05). Compared with those when the target blood pressure was reached after infusion of dobutamine, HR and MAP of patients were significantly decreased at 10 minutes after tracheal catheter removal (P<0.05). The area ratio of flaps with hyperperfusion of patients was 0.63±0.11 when the target blood pressure was reached after infusion of dobutamine, which was significantly higher than 0.31±0.09 at 10 minutes after vascular recanalization (t=-9.92, P<0.05). The area ratio of flaps with hypoperfusion of patients was 0.12±0.05 when the target blood pressure was reached after infusion of dobutamine, which was significantly lower than 0.45±0.10 at 10 minutes after vascular recanalization (t=17.05, P<0.05). The flap harvesting area of patients was (174±35) cm², the surgical duration was (372±52) min, the total fluid infusion amount was (2 485±361) mL, the infusion dose of dobutamine was 3-13 μg·kg⁻¹·min⁻¹, and the total usage of dobutamine was 5.7 (2.1, 9.7) mg. Two patients showed a significant increase in MAP during the infusion of dobutamine compared with that at 10 minutes after vascular recanalization, but before reaching 6 mmHg higher than that before anesthesia induction, their HR had reached the maximum (over 130 beats/min). The HR gradually returned to around 90 beats/min after the infusion of dobutamine was stopped. On post operation day 2, one patient had partial necrosis at the distal part of the flap, which was repaired by transplantation of thin split-thickness skin graft from the opposite thigh. During the follow-up of 3 to 6 months after operation, all the flaps survived well, with soft texture and well-formed shape, and no adverse cardiovascular events of patients were reported. Conclusions: The administration of dobutamine in free flap repair of diabetic foot wounds can significantly improve the MAP of patients, expand the area of hyperperfusion, reduce the area of hypoperfusion, and enhance the flap viability, with promising short-term follow-up results, which is suitable for promotion in clinical applications.