Sublingual microcirculatory alterations during the immediate and early postoperative period: A systematic review and meta-analysis

Abstract

BACKGROUND: The incidence of postoperative microcirculatory flow alterations and their effect on outcome have not been studied extensively. OBJECTIVE: This systematic review and meta-analysis was designed to investigate the presence of sublingual microcirculatory flow alterations during the immediate and early postoperative period and their correlation with complications and survival. METHODS: A systematic search of PubMed, Scopus, Embase, PubMed Central, and Google Scholar was conducted for relevant articles from January 2000 to March 2021. Eligibility criteria were randomized controlled and non-randomized trials. Case reports, case series, review papers, animal studies and non-English literature were excluded. The primary outcome was the assessment of sublingual microcirculatory alterations during the immediate and early postoperative period in adult patients undergoing surgery. Risk of bias was assessed with the Ottawa-Newcastle scale. Standard meta-analysis methods (random-effects models) were used to assess the difference in microcirculation variables. RESULTS: Thirteen studies were included. No statistically significant difference was found between preoperative and postoperative total vessel density (p = 0.084; Standardized Mean Difference (SMD): –0.029; 95%CI: –0.31 to 0.26; I2 = 22.55%). Perfused vessel density significantly decreased postoperatively (p = 0.035; SMD: 0.344; 95%CI: 0.02 to 0.66; I2 = 65.66%), while perfused boundary region significantly increased postoperatively (p = 0.031; SMD: –0.415; 95%CI: –0.79 to –0.03; I2 = 37.21%). Microvascular flow index significantly decreased postoperatively (p = 0.028; SMD: 0.587; 95%CI: 0.06 to 1.11; I2 = 86.09%), while no statistically significant difference was found between preoperative and postoperative proportion of perfused vessels (p = 0.089; SMD: 0.53; 95%CI: –0.08 to 1.14; I2 = 70.71%). The results of the non-cardiac surgery post-hoc analysis were comparable except that no statistically significant difference in perfused vessel density was found (p = 0.69; SMD: 0.07; 95%CI: –0.26 to 0.39; I2 = 0%). LIMITATIONS: The included studies investigate heterogeneous groups of surgical patients. There were no randomized controlled trials. CONCLUSIONS: Significant sublingual microcirculatory flow alterations are present during the immediate and early postoperative period. Further research is required to estimate the correlation of sublingual microcirculatory flow impairment with complications and survival.

Association of effective circulating blood volume with sublingual RBC velocity and microvessel pressure difference in anesthetized individuals: A clinical investigation and computational fluid dynamics modeling

“…In clinical practice, a fluid challenge may increase the stressed volume (and thus Pmca and CO) until a certain point, but may not always improve microcirculatory perfusion. On the other hand, fluid overload increases CVP, which decreases venous return and retrogradely increases post-capillary venular pressure, impairing microcirculatory perfusion [39-41]. The association between the Pmca and Δp ranges in our study (Figure 3) further enhances the potential of Pmca to serve as a hemodynamic coherence monitoring tool.…”

Association of Preoperative Basal Inflammatory State, Measured by Plasma suPAR Levels, with Intraoperative Sublingual Microvascular Perfusion in Patients Undergoing Major Non-Cardiac Surgery

“…Preoperative CPR levels were not correlated with intraoperative sublingual microcirculation. Our findings suggest that basal inflammatory state, measured by suPAR, synergizes with operative trauma to mediate microvascular dysfunction, which in turn has been suggested to mediate postoperative complications [ 44 ]. The association between the level of preoperative systemic inflammation and intraoperative impairment of sublingual microvascular perfusion may be particularly important during prolonged anesthetic/surgical duration.…”

“…In a prospective observational study with 25 patients receiving standard perioperative care following major abdominal surgery, microcirculatory flow impairment was associated with higher rates of postoperative complications [ 48 ]. In addition, a recent systematic review and meta-analysis reported significant sublingual microcirculatory flow alterations during the immediate and early postoperative period [ 44 ]. However, the exact underlying mechanisms between chronic inflammation and microvascular impairment are not fully understood.…”

“…In these individuals, graded changes in vascular shear rate, even for brief periods, elicit progressive recruitment of both rolling and firmly adherent leukocytes [ 5 ]. The activated leukocytes cause oxidative and enzymatic degradation of the glycocalyx and further impair microvascular perfusion [ 6 , 44 ]. All these are consistent with our findings, which indicate a strong association between suPAR, microcirculatory flow impairment, and postoperative complications.…”

“…All these are consistent with our findings, which indicate a strong association between suPAR, microcirculatory flow impairment, and postoperative complications. Given that sublingual microcirculatory alterations occurring during surgery may be maintained during the immediate and early postoperative period [ 44 , 48 ], the role of chronic inflammation appears to be important in the development of postoperative complications.…”