Cutaneous microcirculation during operations with a cardiopulmonary bypass

Application of ultrasound microbubble contrast to evaluate the effect of sitaxentan on renal microvascular perfusion in beagles undergoing cardiopulmonary bypass

BACKGROUND & OBJECTIVE

We aimed to evaluate the effect of sitaxentan on renal microvascular perfusion via application of ultrasound microbubble contrast.

METHODS

Male beagles were randomly divided into: Sham, cardiopulmonary bypass (CPB) and sitaxentan-infused (Sit) groups (n = 6). The ascending slope rate (ASR), area under the curve (AUC), derived peak intensity, and time to peak (TTP) were obtained via ultrasound microbubble contrast before CPB (T1), after 1 h CPB (T2), at end of CPB (T3), and 2 h after CPB (T4).

RESULTS

Compared with the Sham group, the CPB group had lower ASR of the renal cortex and medulla at T2 - 4, higher AUC and TTP at T3 - 4, and lower derived peak intensity at T4. The ASR at T2 - 4 in the Sit group was lower, TTP was higher at T2 - 4, and AUC was higher at T3 - 4 (P < 0.05). Compared with the CPB group, the Sit group had higher ASR of the renal cortex and medulla at T3 - 4 and AUC and TTP at T3 - 4 (P < 0.05). Compared with that at T1, the ASR of the renal cortex and medulla at T2 - 4 in the CPB group was lower, and AUC and TTP were higher at T3 - 4. The ASR of the renal cortex and medulla at T2 - 4 in the Sit group was lower, TTP was higher at T2 - 4, and AUC was higher at T4 (P < 0.05).

CONCLUSIONS

Ultrasound microbubble contrast could be effectively used to evaluate renal microvascular perfusion peri-CPB in beagles, which was prone to decrease and could be improved via pretreatment with sitaxentan.

Theoretical and Practical Aspects in the Use of Bretschneider Cardioplegia

The race for an ideal cardioplegic solution has remained enthusiastic since the beginning of the modern cardiac surgery era. The Bretschneider solution, belonging to the “intracellular cardioplegic” group, is safe and practical in myocardial protection during ischemic time. Over time, some particular concerns have arisen regarding the effects on cardiac metabolism and postoperative myocardial functioning. This paper reviews the most important standpoints in terms of theoretical and practical analyses.

Impact of skeletonized harvesting of the internal thoracic artery on intrasternal microcirculation considering preparation quality

OBJECTIVES

Previous studies have demonstrated the impact of internal thoracic artery (ITA) harvesting on microcirculation in parasternal tissues. However, the impact of skeletonized ITA harvesting on intrasternal microcirculation is unknown. Intraskeletal tissue perfusion has been proven to be crucial for deep wound healing. Furthermore, the impact of different levels of surgical preparation quality on intrasternal microcirculation has not been investigated yet.

METHODS

Sternal microcirculation (sLDP) was monitored with a novel Laser Doppler Perfusion needle probe, while the ITA was skeletonized in a pig model. To mimic different levels of preparation quality, satellite veins were either coagulated or not during preparation. To show the effect of ideally avoiding any surgical manipulation on sLDP, the ITA was clipped in a third sham-harvested group.

RESULTS

sLDP was reduced highly significant to 71 [standard deviation (SD): 9]% (P < 0.001) after skeletonized harvesting of the ITA. Coagulation of the satellite veins as a detrimental surgical factor resulted in a significantly stronger reduction of sLDP to 56 (SD: 11)% (P < 0.05) compared to sLDP with non-coagulated satellite veins. ITA clipping reduced sLDP highly significant to 71 (SD: 8)% (P < 0.001) in the sham-operated group.

CONCLUSIONS

ITA harvesting markedly impairs microcirculation of the sternum but remains unavoidable when coronary artery bypass grafting should be performed. Nevertheless, excessive surgical damage and coagulation of satellite veins is avoidable and should be reduced to a minimum to minimize the risk of deep sternal wound healing complications.