Журнал «Медицина неотложных состояний» 8 (55) 2013

The aim of thisstudy was to determinethe dynamicsof vascular toneusingtechniquescombinedcentralα2a-NMDA sedationwith fentanyl.

Materials and methods: In order to solve this problem in «S. P. Grigoyev Institute of Medical Radiology of Ukraine NAMS" was conducted the study, during 2013-2015. Research Design: a prospective cohort. All patients gave informed consent to the study. It was attended 105 patients with breast cancer. All patients were divided depending on the method of anesthesia into two groups. 1 (n = 46) - the first group, in which anesthesia was performed by standard method: induction by 40 mg of propofol 1% solution every 10 sec. to the onset of clinical anesthesia stage III₁ (1,5-2,5 mg/kg) and, after intubation and start of mechanical ventilation, continuous propofol infusion 6.12 mg / kg / h. Postoperative analgesia was performed at the patient's request with promedol 2 % -1 ml IM. 2 (n = 59) - the second group anesthesia was like in 1, with adding a in-step induction with dexmedetomidine - loading dose 0.7 mg / kg for 10 min and support dose 0.3 mg / kg / h. Postoperative analgesia was performed with naropin 3 mg/kg/day continuous infusion through catheter positioned near muscle graft.

Since reaction-on-pain closely related with vasomotor function, and the quickly awakening after anesthesia is closely related to pulmonary blood flow, state of local blood flow with pulmonary vascular resistance (PVR, 50-150 dynes * sec / cm^-5 ) was investigated thermodilutionally. Systemic blood flow was evaluated on the total peripheral vascular resistance (TPVR, 800-1500 dyn/sec * cm^-5) with the Fick method.

Results: In 1^st group, TPVR began to increase (р=0,0000284) from induction, with its maximum on 1^stp.o. day 2562,6+21,2dyn/sec * cm^-5(р=0,000375)/ TPVR began to decrease (р=0,0000847) on 3^rdp.o. day and returned to normal only on 10^thp.o. day (р=0,0000385). PVR increased ( p = 0.0000385 ) by 62.7% on 3^rdp.o. day, compared to base stage. On 28^thp.o. day PVR return to the normal limit , which was (p = 0.0000485 ) 42.9 % less compared to a 10^thp.o. day maximum (105,1+14,2dyn/sec * cm^-5).

In 2^nd group, TPVR had not significantdynamics (p = 0.089304) and fluctuatedwithin the normal range. PVR decreased by 29,9% (р=0,000394) during anesthesia and began to rise after ending of central α_2a -NMDA sedation, all time being in normal limits.

Implementation of the combined central α_2a -NMDA sedation with fentanyl led to immediate sympatholytic effect after its application. The duration of this effect is unknown due to lack of rebound increase in vascular tone after the expiration of sympathetic blockade, which might possibly be interpreted as a positive effect. In contrast to this, use of standard methods of analgesia led to detectable vasopressionintrinsical to narcotic analgesics. Its duration was three days, due to the wide use of parenteral analgesics for pain relief in the postoperative period.

Sympatholytic effect of α_2a -NMDA sedation with fentanyl resulted not only in decreasing of total peripheral vascular tone, but also caused a positive effect on the state of pulmonary blood flow by decreasing pulmonary resistance, thereby increasing the oxygenation process.

The maximum effect of increased pulmonary blood flow was observed in the first postoperative day with a smooth return to normal physiological limits, which concurred with functional activation of patients in the postoperative morning. In contrast to this, the application of a standard anesthesia along with an increase in overall vascular tone led to parallel deterioration of pulmonary blood flow. An interesting fact is a period of negative factors occurring - 3-10 p.o. days. It is hard to line direct connection with anesthesia, but because of the dynamics described above, we can make assumption of rebound effect due to redistribution of systemic blood flow.

Conclusions:

1. Sympatholytic effect of α_2a -NMDA sedation with fentanyl resulted decreasing of total peripheral vascular tone and pulmonary vascular resistance, thereby increasing the oxygenation process.2. The maximum effect of increased pulmonary blood flow was observed in the first postoperative day with a smooth return to normal physiological limits, which concurred with functional activation of patients in the postoperative period ;3. Standard anesthesia cause increase in overall vascular tone with parallel deterioration of pulmonary blood flow.

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