May Renal Resistive Index Be an Early Predictive Tool of Postoperative Complications in Major Surgery? Preliminary Results

Abstract

Background. Patients who undergo high-risk surgery represent a large amount of post-operative ICU-admissions. These patients are at high risk of experiencing postoperative complications. Renal Resistive Index was found to be related with renal dysfunction, hypertension, and posttraumatic hemorrhagic shock, probably due to vasoconstriction. We explored whether Renal Resistive Index (RRI), measured after awakening from general anesthesia, could have any relationship with postoperative complications. Methods. In our observational, stratified dual-center trial, we enrolled patients who underwent general anesthesia for high-risk major surgery. After awakening in recovery room (or during awakening period in subjects submitted to cardiac surgery) we measured RRI by echo-color-Doppler method. Primary endpoint was the association of altered RRI (>0.70) and outcome during the first postoperative week. Results. 205 patients were enrolled: 60 (29.3%) showed RRI > 0.70. The total rate of adverse event was 27 (18.6%) in RRI ≤ 0.7 group and 19 (31.7%) in RRI > 0.7 group (P = 0.042). Significant correlation between RRI > 0.70 and complications resulted in pneumonia (P = 0.016), septic shock (P = 0.003), and acute renal failure (P = 0.001) subgroups. Patients with RRI > 0.7 showed longer ICU stay (P = 0.001) and lasting of mechanical ventilation (P = 0.004). These results were confirmed in cardiothoracic surgery subgroup. RRI > 0.7 duplicates triplicates the risk of complications, both in general (OR 2.03 93 95% CI 1.02–4.02, P = 0.044) and in cardiothoracic (OR 2.62 95% CI 1.11–6.16, P = 0.027) population. Furthermore, we found RRI > 0.70 was associated with a triplicate risk of postoperative septic shock (OR 3.04, CI 95% 1.5–7.01; P = 0.002).

Renal Resistive Index: A Tool for Postoperative Intensive Care Unit-Outcome? A Pilot Observational Study

“…There is a general consensus about a cutoff range of RRI 0.70÷0.74 to define patients exposed to a significant risk of AKI or other adverse events after major surgery (10,11). In our sample the median value was a little lower (RRI 0.68) than the cutoff.…”

Factors for postoperative complications following pressure ulcer operation: stepwise multiple logistic regression analysis

“…Based on previous reports of risk factors related to surgery, we gathered information regarding the history of cardiac ischaemia , renal failure , ventilator use and tracheostomy , which are known to be associated with postoperative cardiopulmonary risk. A history of angina or myocardial infarction was considered cardiac ischaemia, and patients who were currently receiving dialysis were considered to have renal failure.…”

Renal Resistive Index: Response to Shock and its Determinants in Critically Ill Patients

“…High RRI can be caused by vasoconstriction, decreased vascular compliance, or capillary rarefaction, and is associated with renal arterial disease (4). RRI seems a promising tool to predict the development and reversibility of AKI in critically ill patients (5–7). Up to now, there are no studies in intensive care patients showing that RRI is increased in shock.…”