Tissue near infra red spectroscopy change is not correlated with patients' outcome in elective cardiac surgery.

BACKGROUND: Microcirculatory disturbances following cardiac surgery with cardiopulmonary bypass (CPB) are thought to be at the origin of organ dysfunction, although few studies have correlated microvascular alterations with outcome. We aimed to assess the microcirculation with near infrared spectroscopy (NIRS) and correlate NIRS parameters with intensive care length of stay and organ dysfunction. METHODS: Forty patients at increased risk of postoperative systemic inflammatory response syndrome after an elective cardiac surgery with CPB were included in this prospective observational study. Microcirculation of the thenar eminence was analysed by NIRS technology, through the tissue oxygen saturation (StO2 ) and the recovery slope after an ischaemic challenge. Organ dysfunction was assessed with the Sequential Organ Failure Assessment (SOFA) score. Microcirculation parameters were recorded at baseline, at different time points during the surgery and the first 48 postoperative hours. RESULTS: StO2 at baseline was 82% and decreased significantly until 77% at 2 h after CPB. Recovery slope values were 4.3% per second at baseline and decreased to 2.5% per second during CPB (P < 0.05). From 12 h after CPB time point, both parameters were not statistically different from baseline anymore. We found no correlation between microcirculatory parameters and mean arterial pressure, cardiac index, intensive care unit (ICU) length of stay or SOFA score. CONCLUSION: This study confirms, through a non-invasive technology, a significant but transient alteration of the microcirculation during elective cardiac surgery. However, as these microvascular alterations were not correlated with patient's outcome, NIRS-derived parameters seem to be of limited interest in the cardiac surgery setting.

Haemodynamic consequences of etomidate administration in elective cardiac surgery: a randomized double-blinded study.

BACKGROUND: The consequences of inhibition of cortisol synthesis by a single dose of etomidate on subsequent vasopressor drug usage and the duration of relative adrenal insufficiency (RAI) after cardiac surgery are not known. METHODS: This was a prospective, randomized, double-blinded controlled trial of 100 patients undergoing elective cardiac surgery and receiving either etomidate or propofol at induction of anaesthesia. A short corticotropin test was performed 12, 24, and 48 h after anaesthesia induction. RAI was defined as a response <250 nmol litre(-1). RESULTS: The mean (sd) norepinephrine infusion rate during the first 48 postoperative hours was 0.11 (0.01) and 0.11 (0.01) µg kg(-1) min(-1) in the etomidate and propofol groups, respectively (P=0.89). Time to norepinephrine withdrawal was similar between the groups. The incidence of RAI was higher in the etomidate group at 12 h (100% vs 41%, P<0.001) and 24 h (85% vs 25%, P<0.001). CONCLUSIONS: A single bolus of etomidate blunts the hypothalamic-pituitary-adrenal axis response for more than 24 h in patients undergoing elective cardiac surgery, but this was not associated with an increase in vasopressor requirements.

Cardiac risk assessment of asymptomatic patients by stress echocardiography before infrarenal aortic aneurysm surgery.

AIM: Aggressive cardiac assessment before aortic abdominal aneurysm (AAA) surgery is indicated for patients with symptomatic coronary artery disease (CAD). Assessment of intermediate and moderate risk patients is still under debate. The purpose of the study was to prospectively evaluate the effectiveness of stress echocardiography (SE) in the detection of CAD in patients undergoing AAA surgery who have no symptoms and/or signs of CAD, but who have risk factors for it. METHODS: Patients with 1 or more risk factors for CAD underwent SE. All patients with positive SE underwent coronary arteriography, and, when indicated, treatment. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for SE by comparing results to coronary arteriography. Moreover, major perioperative cardiac events were recorded. RESULTS: Ninety-one patients with AAA and risk factors for CAD were studied. SE was positive in 9 cases, including 7 presenting critical CAD on the basis of coronary arteriography. One major cardiac event (1.1%), a nonfatal myocardial infarction, occurred in 1 patient with positive SE and non-critical, single-vessel CAD. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SE proved to be 100%, 98%, 78%, 100%, and 92%, respectively. CONCLUSIONS: Positive SE should be considered a valid method for testing high-risk patients for CAD. The low rate of major cardiac events in this series suggests that cardiac assessment by SE and selective coronary arteriography prior to AAA surgery is effective in asymptomatic patients with one or more risk factors.