The effect of moderate intraoperative blood loss and norepinephrine therapy on sublingual microcirculatory perfusion in patients having open radical prostatectomy

Abstract

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Microcirculatory tissue perfusion during general anaesthesia and noncardiac surgery

“…These contradictory observations may, in part, result from using different camera technologies and analysis methods. Further, studies reporting preserved FCD found either increased 20 or decreased 19 microvascular blood flow. In our study, preserved tRBCp and FCD indicate that microcirculatory tissue perfusion was not impaired under general anaesthesia before surgical incision -despite reduced microcirculatory flow (RBCv and PPV) and clinically important decreases in blood pressure and cardiac output.…”

“…Previous studies investigating the effects of general anaesthesia on sublingual microcirculatory tissue perfusion showed inconsistent results. Some studies found reduced 18,21 and others preserved 19,20 FCD under general anaesthesia compared with pre-induction baseline. These contradictory observations may, in part, result from using different camera technologies and analysis methods.…”

“…Previous studies also observed that sublingual microcirculatory tissue perfusion was maintained during noncardiac surgery, even during major abdominal surgery. 19,20,22 This may be surprising as one could assume that surgical trauma causes systemic inflammation, and thus, impairs microcirculatory tissue perfusion. However, microcirculatory tissue perfusion seems to be preserved during surgery -at least when macrocirculatory haemodynamics are maintained.…”

“…Therefore, we did not perform a formal sample size calculation. On the basis of previous studies investigating sublingual microcirculatory tissue perfusion in surgical patients, [18][19][20][21] we estimated that a total number of 120 patients (40 patients per group) would be sufficient to identify clinically meaningful changes in microcirculatory tissue perfusion. A sample size of 40 patients per group achieves 87% power to detect a medium effect size of 0.5 with a significance level of 5% using a two-sided paired t-test (calculated using PASS 2008; NCSS, Kaysville, Utah, USA).…”