Dexmedetomidine versus remifentanil for sedation under monitored anesthetic care in complex endovascular aortic aneurysm repair: a single center experience with mid-term follow-up.

BACKGROUND: Sedation protocols in patients undergoing complex endovascular aortic aneurysm repair are not fully investigated. The aim of this study was to compare a dexmedetomidine (DEX) based sedation protocol with a remifentanil-based sedation protocol. METHODS: Seventy-nine consecutive patients undergoing complex endovascular aortic repair were enrolled and retrospectively analyzed. Forty-two received 0.03 mg/kg midazolam intravenous bolus with remifentanil (0.075-0.1 µg/kg/min for 10 minutes followed by continuous infusion 0.050-0.25 µg/kg/min) and 37 DEX (1 µg/kg over 10 minutes and continuous infusion 0.50-0.75 µg/kg/hour) to achieve an Observer Assessment of Alertness/Sedation Scale (OAAS) ≤4, a Richmond Agitation/Sedation Scale (RASS) ≤-2 and a Visual Analogic Scale (VAS) <4. The primary endpoint was patients' satisfaction. Secondary endpoints included assessment of sedation and pain, the incidence of perioperative hemodynamic or gas exchange imbalance, and 36 month-mortality. RESULTS: Remifentanil group showed a higher satisfaction rate than DEX (P<0.001). Patients on DEX were more sedated than remifentanil according to OAAS (3 [2-3] vs. 4 [3-4]; P=0.001) and RASS (-2[-3/-2] vs. -2[-2/-2]; P=0.001) with no difference in VAS (2 [1-3] vs. 2 [1-3]; P=0.41). DEX provides reliable sedation with lower patient's satisfaction. A higher number of patients were discharged from the recovery room on vasopressors in the DEX group compare with the remifentanil group (5 vs. 0; P=0.045, respectively). The two groups showed a non-significant difference in the survival rate at 36-month (DEX 67% vs. remifentanil 73%; (P=0.90). CONCLUSIONS: In this setting remifentanil provides reliable sedation with higher patient's satisfaction and less hemodynamic effect than DEX.

Dynamic arterial elastance measured with pressure recording analytical method, and mean arterial pressure responsiveness in hypotensive preload dependent patients undergoing cardiac surgery: A prospective cohort study.

BACKGROUND: Organ perfusion is a factor of cardiac output and perfusion pressure. Recent evidence shows that dynamic arterial elastance is a reliable index of the interaction between the left ventricle and the arterial system and, in turn, of left ventricular mechanical efficiency. A practical approach to the assessment of dynamic arterial elastance at the bedside is the ratio between pulse pressure variation and stroke volume variation, which might predict the effect of a fluid challenge on the arterial pressure in patients undergoing cardiac surgery. OBJECTIVE: To evaluate the ability of dynamic arterial elastance, measured by the pressure recording analytical method (PRAM), to predict the response of mean arterial pressure (MAP) to a fluid challenge. DESIGN: Prospective observational study. SETTING: Cardiac surgery patients in a university hospital. PATIENTS: Preload-dependent (pulse pressure variation ≥13%), hypotensive (MAP ≤65 mmHg) patients, without right ventricular dysfunction, at the end of cardiac surgery. INTERVENTIONS: A 250 ml fluid challenge infused over 3 min. MAIN OUTCOME MEASURES: A receiver-operating characteristic curve was generated to test the ability of the baseline (before fluid challenge) dynamic arterial elastance (primary endpoint) and all other haemodynamic variables (secondary endpoint) to predict MAP responsiveness (≥10% increase in MAP) after a fluid challenge. RESULTS: Of 270 patients undergoing cardiac surgery, 97 (35.9%) were preload-dependent, hypotensive and received a fluid challenge. Of these 97 patients, 50 (51%) were MAP responders (≥10% increase in MAP) and 47 (48%) were MAP nonresponders (<10% increase in MAP). Baseline dynamic arterial elastance (mean ±â€ŠSD) had an area under the curve of 0.64 ±â€Š0.06 [95% confidence interval (CI), 0.53 to 0.73; P = 0.017]. A dynamic arterial elastance at least 1.07 with a grey zone ranging between 0.9 and 1.5 had 86% sensitivity (95% CI, 73 to 94) and 45% specificity (95% CI, 30 to 60) in predicting MAP increase. CONCLUSION: In a hypotensive preload-dependent cardiac surgery cohort without right ventricular dysfunction, dynamic arterial elastance measured by PRAM can predict pressure response for values greater than 1.5 or less than 0.9.